Psoriatic Arthritis

Smoking is another important modifiable environmental factor. Smoking generally has an adverse impact on treatment. In a post hoc analysis of pooled data from phase 2 and 3 trials and a long-term extension study involving 914 patients with PsA and 372 patients with ankylosing spondylitis who received tofacitinib (a Janus kinase inhibitor) or placebo, Ogdie and coworkers assessed the impact of smoking on treatment efficacy and safety. The efficacy rates were generally similar in current/past smokers and never-smokers. The incidence rates of treatment-emergent adverse events were higher in current/past smokers compared with never-smokers. Thus, in contrast to tumor necrosis factor inhibitors, smoking status may not have an impact on tofacitinib efficacy. However, current/past smokers experienced increased rates of adverse events.

Secukinumab, an anti-interleukin (IL)-17A antibody, is an established treatment for PsA and is approved for use as fixed-dose (150/300 mg) subcutaneous injections. The efficacy and safety of weight-based intravenous (IV) therapy is unknown. Kivitz and colleagues recently reported the results of the phase 3 INVIGORATE-2 trial, in which 381 patients with active PsA and either plaque psoriasis or nail psoriasis were randomly assigned to receive IV secukinumab or placebo with crossover to IV secukinumab at week 16. They demonstrated that at week 16, IV secukinumab significantly improved the American College of Rheumatology 50 response rate (ACR50) compared with placebo (31.4% vs 6.3%; adjusted P < .0001). Improvements were observed as early as week 4 and were sustained through week 52. No new safety signals were reported. Thus, IV secukinumab is a safe and efficacious treatment for PsA. This mode of administration of secukinumab is a welcome addition to the PsA therapeutic armamentarium.

There are many targeted therapies available for PsA. However, data on comparative effectiveness is lacking. Kristensen and associates reported the results of an interim analysis of the PRO-SPIRIT real-world study that included 1192 patients with PsA across six countries who initiated or switched to a new biologic or targeted synthetic disease-modifying antirheumatic drug. They showed that at 3 months, ixekizumab significantly improved clinical disease activity in patients with PsA compared with IL-12/23 inhibitors and IL-23 inhibitors. The improvements in the joints were similar to those with TNF inhibitors and JAK inhibitors, but the improvement in psoriasis was higher. Thus, ixekizumab leads to rapid response to active skin and musculoskeletal disease activity in PsA. Comparative data on treatment persistence as well as adverse events are required.

Smoking is another important modifiable environmental factor. Smoking generally has an adverse impact on treatment. In a post hoc analysis of pooled data from phase 2 and 3 trials and a long-term extension study involving 914 patients with PsA and 372 patients with ankylosing spondylitis who received tofacitinib (a Janus kinase inhibitor) or placebo, Ogdie and coworkers assessed the impact of smoking on treatment efficacy and safety. The efficacy rates were generally similar in current/past smokers and never-smokers. The incidence rates of treatment-emergent adverse events were higher in current/past smokers compared with never-smokers. Thus, in contrast to tumor necrosis factor inhibitors, smoking status may not have an impact on tofacitinib efficacy. However, current/past smokers experienced increased rates of adverse events.

Secukinumab, an anti-interleukin (IL)-17A antibody, is an established treatment for PsA and is approved for use as fixed-dose (150/300 mg) subcutaneous injections. The efficacy and safety of weight-based intravenous (IV) therapy is unknown. Kivitz and colleagues recently reported the results of the phase 3 INVIGORATE-2 trial, in which 381 patients with active PsA and either plaque psoriasis or nail psoriasis were randomly assigned to receive IV secukinumab or placebo with crossover to IV secukinumab at week 16. They demonstrated that at week 16, IV secukinumab significantly improved the American College of Rheumatology 50 response rate (ACR50) compared with placebo (31.4% vs 6.3%; adjusted P < .0001). Improvements were observed as early as week 4 and were sustained through week 52. No new safety signals were reported. Thus, IV secukinumab is a safe and efficacious treatment for PsA. This mode of administration of secukinumab is a welcome addition to the PsA therapeutic armamentarium.

There are many targeted therapies available for PsA. However, data on comparative effectiveness is lacking. Kristensen and associates reported the results of an interim analysis of the PRO-SPIRIT real-world study that included 1192 patients with PsA across six countries who initiated or switched to a new biologic or targeted synthetic disease-modifying antirheumatic drug. They showed that at 3 months, ixekizumab significantly improved clinical disease activity in patients with PsA compared with IL-12/23 inhibitors and IL-23 inhibitors. The improvements in the joints were similar to those with TNF inhibitors and JAK inhibitors, but the improvement in psoriasis was higher. Thus, ixekizumab leads to rapid response to active skin and musculoskeletal disease activity in PsA. Comparative data on treatment persistence as well as adverse events are required.

Smoking is another important modifiable environmental factor. Smoking generally has an adverse impact on treatment. In a post hoc analysis of pooled data from phase 2 and 3 trials and a long-term extension study involving 914 patients with PsA and 372 patients with ankylosing spondylitis who received tofacitinib (a Janus kinase inhibitor) or placebo, Ogdie and coworkers assessed the impact of smoking on treatment efficacy and safety. The efficacy rates were generally similar in current/past smokers and never-smokers. The incidence rates of treatment-emergent adverse events were higher in current/past smokers compared with never-smokers. Thus, in contrast to tumor necrosis factor inhibitors, smoking status may not have an impact on tofacitinib efficacy. However, current/past smokers experienced increased rates of adverse events.

Secukinumab, an anti-interleukin (IL)-17A antibody, is an established treatment for PsA and is approved for use as fixed-dose (150/300 mg) subcutaneous injections. The efficacy and safety of weight-based intravenous (IV) therapy is unknown. Kivitz and colleagues recently reported the results of the phase 3 INVIGORATE-2 trial, in which 381 patients with active PsA and either plaque psoriasis or nail psoriasis were randomly assigned to receive IV secukinumab or placebo with crossover to IV secukinumab at week 16. They demonstrated that at week 16, IV secukinumab significantly improved the American College of Rheumatology 50 response rate (ACR50) compared with placebo (31.4% vs 6.3%; adjusted P < .0001). Improvements were observed as early as week 4 and were sustained through week 52. No new safety signals were reported. Thus, IV secukinumab is a safe and efficacious treatment for PsA. This mode of administration of secukinumab is a welcome addition to the PsA therapeutic armamentarium.

There are many targeted therapies available for PsA. However, data on comparative effectiveness is lacking. Kristensen and associates reported the results of an interim analysis of the PRO-SPIRIT real-world study that included 1192 patients with PsA across six countries who initiated or switched to a new biologic or targeted synthetic disease-modifying antirheumatic drug. They showed that at 3 months, ixekizumab significantly improved clinical disease activity in patients with PsA compared with IL-12/23 inhibitors and IL-23 inhibitors. The improvements in the joints were similar to those with TNF inhibitors and JAK inhibitors, but the improvement in psoriasis was higher. Thus, ixekizumab leads to rapid response to active skin and musculoskeletal disease activity in PsA. Comparative data on treatment persistence as well as adverse events are required.

Over the past two decades, the treatment of active psoriatic arthritis (PsA) has been transformed by targeted biologic therapies. In this ReCAP, Dr Eric Ruderman, from the Feinberg School of Medicine at Northwestern University, reports on the safety and efficacy of several approved therapies.

Dr Ruderman first discusses different treatment options, including TNF inhibitors, which have been the standard first-line therapy for nearly two decades. He also reports that other agents, including Il-12/23 inhibitors abatacept, apremilast, and a number of JAK inhibitors, have shown efficacy for patients who don’t respond well or are intolerant to TNF inhibitors.

In recent years, various specific IL-23 inhibitors have been approved to treat psoriasis and, most recently, psoriatic arthritis in psoriasis. Guselkumab, risankizumab, and tildrakizumab were approved to treat the skin disease.

In psoriatic arthritis, guselkumab and risankizumab have also been approved. These drugs have shown more efficacy than the IL-12/23 inhibitor, according to Ruderman, and show a lower risk for infection compared with some of the other agents.

--

Eric M. Ruderman, MD, Professor, Department of Medicine, Division of Rheumatology, Northwestern University Feinberg School of Medicine; Associate Division Chief, Clinical Affairs, Department of Rheumatology, Northwestern Medical Group, Chicago, Illinois

Eric M. Ruderman, MD, has disclosed the following relevant financial relationships:

Serve(d) as a director, officer, partner, employee, advisor, consultant, or trustee for: AbbVie; Amgen; Bristol Myers Squibb; Janssen; Lilly; Merck; Novartis; NS Pharma; UCB

Over the past two decades, the treatment of active psoriatic arthritis (PsA) has been transformed by targeted biologic therapies. In this ReCAP, Dr Eric Ruderman, from the Feinberg School of Medicine at Northwestern University, reports on the safety and efficacy of several approved therapies.

Dr Ruderman first discusses different treatment options, including TNF inhibitors, which have been the standard first-line therapy for nearly two decades. He also reports that other agents, including Il-12/23 inhibitors abatacept, apremilast, and a number of JAK inhibitors, have shown efficacy for patients who don’t respond well or are intolerant to TNF inhibitors.

In recent years, various specific IL-23 inhibitors have been approved to treat psoriasis and, most recently, psoriatic arthritis in psoriasis. Guselkumab, risankizumab, and tildrakizumab were approved to treat the skin disease.

In psoriatic arthritis, guselkumab and risankizumab have also been approved. These drugs have shown more efficacy than the IL-12/23 inhibitor, according to Ruderman, and show a lower risk for infection compared with some of the other agents.

--

Eric M. Ruderman, MD, Professor, Department of Medicine, Division of Rheumatology, Northwestern University Feinberg School of Medicine; Associate Division Chief, Clinical Affairs, Department of Rheumatology, Northwestern Medical Group, Chicago, Illinois

Eric M. Ruderman, MD, has disclosed the following relevant financial relationships:

Serve(d) as a director, officer, partner, employee, advisor, consultant, or trustee for: AbbVie; Amgen; Bristol Myers Squibb; Janssen; Lilly; Merck; Novartis; NS Pharma; UCB

Over the past two decades, the treatment of active psoriatic arthritis (PsA) has been transformed by targeted biologic therapies. In this ReCAP, Dr Eric Ruderman, from the Feinberg School of Medicine at Northwestern University, reports on the safety and efficacy of several approved therapies.

Dr Ruderman first discusses different treatment options, including TNF inhibitors, which have been the standard first-line therapy for nearly two decades. He also reports that other agents, including Il-12/23 inhibitors abatacept, apremilast, and a number of JAK inhibitors, have shown efficacy for patients who don’t respond well or are intolerant to TNF inhibitors.

In recent years, various specific IL-23 inhibitors have been approved to treat psoriasis and, most recently, psoriatic arthritis in psoriasis. Guselkumab, risankizumab, and tildrakizumab were approved to treat the skin disease.

In psoriatic arthritis, guselkumab and risankizumab have also been approved. These drugs have shown more efficacy than the IL-12/23 inhibitor, according to Ruderman, and show a lower risk for infection compared with some of the other agents.

--

Eric M. Ruderman, MD, Professor, Department of Medicine, Division of Rheumatology, Northwestern University Feinberg School of Medicine; Associate Division Chief, Clinical Affairs, Department of Rheumatology, Northwestern Medical Group, Chicago, Illinois

Eric M. Ruderman, MD, has disclosed the following relevant financial relationships:

Serve(d) as a director, officer, partner, employee, advisor, consultant, or trustee for: AbbVie; Amgen; Bristol Myers Squibb; Janssen; Lilly; Merck; Novartis; NS Pharma; UCB

Therapeutic drug monitoring (TDM) — the practice of using laboratory testing to measure blood levels of drugs — has garnered growing interest among rheumatologists in managing patients on disease-modifying antirheumatic drugs (DMARDs), but that hasn’t exactly translated to widespread practice.

While TDM has made some inroads with patients taking monoclonal antibodies, specifically infliximab, its uptake has encountered a number of headwinds, not the least of which is a lack of evidence and clinical guidelines, uneven access and standards of assays, and even an uncertainty about how to interpret laboratory results.

“In some fields, such as neurology, TDM is accepted for antiepileptics,” Michelle Petri, MD, MPH, director of the Johns Hopkins Lupus Center, Baltimore, told Medscape Medical News. “In rheumatology, though, TDM is underutilized and not adequately championed by the American College of Rheumatology.”

Johns Hopkins University

Duke University

Reactive vs Proactive TDM

Among the few trials that examined TDM in rheumatology patients are the NOR-DRUM A and B trials in Norway. Marthe Brun, MD, PhD, a rheumatologist at the Center for Treatment of Rheumatic and Musculoskeletal Diseases at Diakonhjemmet Hospital in Oslo, Norway, and a coauthor of the NOR-DRUM trials, told Medscape Medical News that the trials found an overall benefit to TDM during infliximab maintenance therapy. The trials included not only patients with inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, and spondyloarthritis) but also patients with inflammatory bowel disease and psoriasis, Brun said.

Nicolas Tourrenc

Brun explained that two types of TDM exist: Reactive and proactive. “Reactive TDM is when you use it to find the reason for a patient having a flare or disease worsening,” she told Medscape Medical News. “Proactive TDM would be regular testing to keep a patient within a therapeutic range to avoid flare because of low drug concentrations.”

Gastroenterologists are more inclined than rheumatologists and dermatologists to use reactive TDM, she said. “There have been no recommendations regarding proactive TDM because of the lack of data.”

In Europe, Wallace noted that European Alliance of Associations for Rheumatology (EULAR) recommendations consider the use of TDM in specific clinical scenarios, such as when treatment fails or to evaluate immunogenicity of a reaction, but they are limited. The American College of Rheumatology (ACR) does not have any recommendations for the use of TDM.

Based on the NOR-DRUM trials, rheumatologists in Norway have published their own guidelines for TDM for infliximab in rheumatologic disease, but they are in Norwegian and have not yet been taken up by EULAR, Brun noted. Publication of those recommendations in English is pending, she said.

“But for other subcutaneously administered TNF inhibitors, there’s a lack of data,” Brun added.
 

The State of the Evidence

NOR-DRUM A did not support the use of proactive TDM in the 30-week induction period as a way to improve disease remission in patients with chronic immune-mediated inflammatory disease. NOR-DRUM B, which evaluated TDM over a year, found the approach was more likely to lead to sustained disease control for that period.

Brun’s group recently published an analysis of the trials. “We did not find an overall effect during the initial phase of the treatment, the first 30 weeks,” she told Medscape Medical News.

“Then we looked at subgroups, and we found that the patients that developed antidrug antibodies [ADAs] had an effect, and ADA are associated with poorer outcomes as well as infusion reactions for patients treated with infliximab.

“So, it’s probably a benefit to be able to detect these ADA early before the patient experiences a disease flare or infusion reaction,” Brun added. “It facilitates for the clinician to take action to, for example, increase the dosing or switch therapy.”

However, the quality of the data supporting TDM in rheumatology is limited, Balevic said. “There’s very good observational data, but we have very few clinical trials that actually leverage TDM,” he said.

NOR-DRUM is the exception, he said. “Ideally, we need more of these dose-optimization trials to help guide clinical practice,” he said. But it stands alone.

Wallace noted several take-home messages from the NOR-DRUM trials, namely that using TDM to prevent ADA may be more effective during the maintenance phase of treatment than the induction phase. However, he said, the evidence is still emerging.

“It’s reasonable to say that we’re at an early stage of the evidence,” he said. “If you look at the large trials that have been done in rheumatology, they’ve combined patients with many different types of conditions, and a lot of our recommendations in rheumatology are disease-specific — in rheumatoid arthritis, in vasculitis. There’s a lack of data in specific diseases to guide or examine what the role of TDM might be.”

In the meantime, no fewer than four clinical trials evaluating TDM with tumor necrosis factor (TNF) inhibitors in rheumatologic diseases are ongoing or have completed but not yet released results, according to Wallace. Three Adalimumab Drug Optimization in Rheumatoid Arthritis trials are underway: The first is evaluating drug tapering vs disease activity score; the second is testing low or usual drug concentration; and the third is studying switches to etanercept or a non-TNF inhibitor drug (abatacept, rituximab, tocilizumab, or sarilumab) in patients failing treatment. Another trial called Tocilizumab Drug Levels to Optimized Treatment in RA is randomizing patients with high drug levels to dose maintenance or dose reduction. All four trials are sponsored by the Reade Rheumatology Research Institute, Amsterdam, the Netherlands.

Until clearer answers emerge from clinical trials, a number of barriers to and questions about the potential for TDM in rheumatology persist.
 

Barriers to Wider Use of TDM

“The biggest barrier with TDM is simply just a lack of what to do with the data,” Balevic said. “The clinician needs clear-cut guidance on what to do with the drug level. So, in other words, what is the target concentration for the drug? And if that target is not the goal, how should that dose be adjusted?”

The optimal drug levels, particularly for the older conventional synthetic DMARDs, simply have not been validated by clinical trials, he said.

“Different studies may report different target drug levels, and this could be due to different underlying population, or a different matrix — a measure of whole blood vs plasma — or even the timing of the sample,” he said. Balevic led a pharmacokinetic study earlier this year that proposed an algorithm for determining the number of missed hydroxychloroquine doses.

“This really goes back to the clinician needing to draw on a lot of pharmacology training to interpret the literature,” Balevic added.

That gets to the need for more education among rheumatologists, as Brun pointed out. “The physician needs to be educated about therapeutic ranges, when to assess concentrations of drug antibodies, and how to react to the results,” Brun said.

Which ADAs to identify is also problematic. “For antidrug antibodies, it’s especially challenging because there are so many assay formats in use, and it’s a bit complicated to analyze these antidrug antibodies,” Brun said. “There’s no consensus on what calibrators to use, and there’s no standardization of how to report the results, so you can’t really compare results from different assays. You need to know what your laboratory is using and how to interpret results from that particular assay, so that’s a challenge.”

Variability in drug tolerance also exists across assays, Wallace noted. “One of the challenges that have come up in the discussion of therapeutic drug monitoring is understanding what the target level is,” he said. “Defining what the target level might be for a specific condition is not something that’s well understood.”

Breaking down the science, he noted that an ADA can bind to a monoclonal antibody, forming an immune complex that avoids detection. Drug-sensitive assays may detect high concentrations of ADAs but miss low or moderate concentrations. Drug-tolerant assays may be more likely to detect low concentrations at ADAs, but the clinical significance is unclear.
 

Cost and Patient Trust as Barriers

“The costs vary a lot from assay to assay,” Brun said. “Some commercial assays can be really expensive.” In Norway, a dedicated lab with its own in-house assays helps to keep costs down, she said.

But that’s not the case in the United States, where insurance coverage can be a question mark, Shivani Garg, MD, a rheumatologist at the University of Wisconsin (UW)-Madison and director of the UW-Madison Health Lupus and Lupus Nephritis Clinics, told Medscape Medical News. “A lot of insurances are covering therapeutic drug monitoring, but for the high-deductible plans, there should be a way to offer these important tests to patients at a lower cost or figure out a way for coverage for those patients so that they can show that there are benefits of therapeutic drug monitoring without being sent a really big bill,” she said.

UW Health

Who May Benefit Most From TDM?

In the NOR-DRUM trials, patients at risk of developing ADA early on, before a disease flare or infusion reaction, seemed to benefit most from TDM. But who are those patients?

“We looked at risk factors for developing antidrug antibodies, and we found that patients with high disease activity when starting treatment, smokers, and patients with rheumatoid arthritis had a higher risk than other patients, as did patients who are not using concomitant immunosuppressive therapy,” Brun said.

“During treatment, we also found that low serum drug levels and drug holidays above 11 weeks were also risk factors,” she added.

The NOR-DRUM researchers also evaluated genetic risk factors and found that patients with the HLA-DQ2 gene variant were also at increased risk of developing ADA.

While NOR-DRUM evaluated only infliximab, some of its lessons may be applied to other DMARDs, Brun said. “We think that for other subcutaneously administered TNF inhibitors, you would probably see the same effect of proactive TDM, but we currently do not have data on that,” she said. A study similar to the NOR-DRUM design will evaluate this in Norway, Brun added.

She explained why the findings with infliximab may extend to adalimumab, which may be the second most immunogenic TNF inhibitor after infliximab. “The administration is different; it’s administered more often than infliximab; that would also make the results more uncertain to generalize to the other treatments, but I would guess there are also benefits of using TDM in other treatments.”
 

Potential Risks for TDM

Wallace has noted that TDM, with the current state of evidence, carries a number of potential risks. “The potential risks might be that you unnecessarily discontinue a medication because you detected an antibody, or the level seems low and you’re not able to get it higher, but the patient is otherwise doing fine,” he said. “You might end up increasing doses of the medicine that would put the patient at potentially increased risk of infection, as well as obviously more costs.”

That would also lead to more utilization of resources and costs, he said. “Some of those reasons are why there has been hesitation with therapeutic drug monitoring,” Wallace added.

A number of questions also surround the use of biosimilars and ADA levels, Wallace said. While a review of clinical trials found no meaningful differences in terms of immunogenicity between biosimilars and reference products, it did note discrepancies in how the agents were evaluated.
 

What DMARDs Are Most Suitable for TDM?

Petri said TDM would be useful for monitoring patients on mycophenolate mofetil. “A trough level can at least tell us if a patient is taking it,” she said. “Tacrolimus, used for lupus nephritis, has well-accepted peak and trough trends due to widespread use in transplant.”

Drugs with a wide variability in pharmacokinetics may also be suitable for TDM, Balevic said. That would include hydroxychloroquine, azathioprine, mycophenolate, or even cyclophosphamide. Drugs that have a narrow therapeutic index, such as tacrolimus, cyclosporine, or again, cyclophosphamide, might also be amenable to TDM, he said.
 

Why Do TDM?

“The two main reasons why somebody would go on to detect drug levels: The first may be to assess medication adherence, and this applies virtually to any drug that rheumatologists use; the second reason is to optimize dozing, either for efficacy purposes or to prevent toxicity,” Balevic said.

“When it comes to optimizing dosing, you should really think about TDM as one tool in our toolbelt,” he said.

Dose is “just a surrogate,” he said. “When we prescribe a drug, what truly matters is the amount of active unbound drug at the site of action. That’s what’s responsible for a drug’s pharmacologic effect.”

However, the same dose, or even the same weight-based dose, does not necessarily mean similar patients will achieve the same amount of exposure to the drug, but TDM can help determine that, he said.
 

What’s Next

Studies into the use of TDM in rheumatology are ongoing. Brun said her group is currently conducting a cost-effective analysis from the NOR-DRUM trials.

“There’s going to be more studies coming out in the next few years, looking at what impact the use of therapeutic drug monitoring might have on outcomes,” Wallace said.

“As we accumulate more and more evidence, we might see organizations like ACR and EULAR start to weigh in more on whether or not therapeutic drug monitoring can or should be used.”

Petri, Brun, and Garg had no relevant disclosures. Wallace disclosed financial relationships with Amgen, Alexion, BioCryst, Boehringer Ingelheim, Bristol Myers Squibb, Medpace, Novartis, Sanofi, Viela Bio, Visterra, Xencor, and Zenas. Balevic disclosed relationships with the National Institutes of Health, the Childhood Arthritis and Rheumatology Research Alliance, and UCB.
 

A version of this article appeared on Medscape.com.

Therapeutic drug monitoring (TDM) — the practice of using laboratory testing to measure blood levels of drugs — has garnered growing interest among rheumatologists in managing patients on disease-modifying antirheumatic drugs (DMARDs), but that hasn’t exactly translated to widespread practice.

While TDM has made some inroads with patients taking monoclonal antibodies, specifically infliximab, its uptake has encountered a number of headwinds, not the least of which is a lack of evidence and clinical guidelines, uneven access and standards of assays, and even an uncertainty about how to interpret laboratory results.

“In some fields, such as neurology, TDM is accepted for antiepileptics,” Michelle Petri, MD, MPH, director of the Johns Hopkins Lupus Center, Baltimore, told Medscape Medical News. “In rheumatology, though, TDM is underutilized and not adequately championed by the American College of Rheumatology.”

Johns Hopkins University

Duke University

Reactive vs Proactive TDM

Among the few trials that examined TDM in rheumatology patients are the NOR-DRUM A and B trials in Norway. Marthe Brun, MD, PhD, a rheumatologist at the Center for Treatment of Rheumatic and Musculoskeletal Diseases at Diakonhjemmet Hospital in Oslo, Norway, and a coauthor of the NOR-DRUM trials, told Medscape Medical News that the trials found an overall benefit to TDM during infliximab maintenance therapy. The trials included not only patients with inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, and spondyloarthritis) but also patients with inflammatory bowel disease and psoriasis, Brun said.

Nicolas Tourrenc

Brun explained that two types of TDM exist: Reactive and proactive. “Reactive TDM is when you use it to find the reason for a patient having a flare or disease worsening,” she told Medscape Medical News. “Proactive TDM would be regular testing to keep a patient within a therapeutic range to avoid flare because of low drug concentrations.”

Gastroenterologists are more inclined than rheumatologists and dermatologists to use reactive TDM, she said. “There have been no recommendations regarding proactive TDM because of the lack of data.”

In Europe, Wallace noted that European Alliance of Associations for Rheumatology (EULAR) recommendations consider the use of TDM in specific clinical scenarios, such as when treatment fails or to evaluate immunogenicity of a reaction, but they are limited. The American College of Rheumatology (ACR) does not have any recommendations for the use of TDM.

Based on the NOR-DRUM trials, rheumatologists in Norway have published their own guidelines for TDM for infliximab in rheumatologic disease, but they are in Norwegian and have not yet been taken up by EULAR, Brun noted. Publication of those recommendations in English is pending, she said.

“But for other subcutaneously administered TNF inhibitors, there’s a lack of data,” Brun added.
 

The State of the Evidence

NOR-DRUM A did not support the use of proactive TDM in the 30-week induction period as a way to improve disease remission in patients with chronic immune-mediated inflammatory disease. NOR-DRUM B, which evaluated TDM over a year, found the approach was more likely to lead to sustained disease control for that period.

Brun’s group recently published an analysis of the trials. “We did not find an overall effect during the initial phase of the treatment, the first 30 weeks,” she told Medscape Medical News.

“Then we looked at subgroups, and we found that the patients that developed antidrug antibodies [ADAs] had an effect, and ADA are associated with poorer outcomes as well as infusion reactions for patients treated with infliximab.

“So, it’s probably a benefit to be able to detect these ADA early before the patient experiences a disease flare or infusion reaction,” Brun added. “It facilitates for the clinician to take action to, for example, increase the dosing or switch therapy.”

However, the quality of the data supporting TDM in rheumatology is limited, Balevic said. “There’s very good observational data, but we have very few clinical trials that actually leverage TDM,” he said.

NOR-DRUM is the exception, he said. “Ideally, we need more of these dose-optimization trials to help guide clinical practice,” he said. But it stands alone.

Wallace noted several take-home messages from the NOR-DRUM trials, namely that using TDM to prevent ADA may be more effective during the maintenance phase of treatment than the induction phase. However, he said, the evidence is still emerging.

“It’s reasonable to say that we’re at an early stage of the evidence,” he said. “If you look at the large trials that have been done in rheumatology, they’ve combined patients with many different types of conditions, and a lot of our recommendations in rheumatology are disease-specific — in rheumatoid arthritis, in vasculitis. There’s a lack of data in specific diseases to guide or examine what the role of TDM might be.”

In the meantime, no fewer than four clinical trials evaluating TDM with tumor necrosis factor (TNF) inhibitors in rheumatologic diseases are ongoing or have completed but not yet released results, according to Wallace. Three Adalimumab Drug Optimization in Rheumatoid Arthritis trials are underway: The first is evaluating drug tapering vs disease activity score; the second is testing low or usual drug concentration; and the third is studying switches to etanercept or a non-TNF inhibitor drug (abatacept, rituximab, tocilizumab, or sarilumab) in patients failing treatment. Another trial called Tocilizumab Drug Levels to Optimized Treatment in RA is randomizing patients with high drug levels to dose maintenance or dose reduction. All four trials are sponsored by the Reade Rheumatology Research Institute, Amsterdam, the Netherlands.

Until clearer answers emerge from clinical trials, a number of barriers to and questions about the potential for TDM in rheumatology persist.
 

Barriers to Wider Use of TDM

“The biggest barrier with TDM is simply just a lack of what to do with the data,” Balevic said. “The clinician needs clear-cut guidance on what to do with the drug level. So, in other words, what is the target concentration for the drug? And if that target is not the goal, how should that dose be adjusted?”

The optimal drug levels, particularly for the older conventional synthetic DMARDs, simply have not been validated by clinical trials, he said.

“Different studies may report different target drug levels, and this could be due to different underlying population, or a different matrix — a measure of whole blood vs plasma — or even the timing of the sample,” he said. Balevic led a pharmacokinetic study earlier this year that proposed an algorithm for determining the number of missed hydroxychloroquine doses.

“This really goes back to the clinician needing to draw on a lot of pharmacology training to interpret the literature,” Balevic added.

That gets to the need for more education among rheumatologists, as Brun pointed out. “The physician needs to be educated about therapeutic ranges, when to assess concentrations of drug antibodies, and how to react to the results,” Brun said.

Which ADAs to identify is also problematic. “For antidrug antibodies, it’s especially challenging because there are so many assay formats in use, and it’s a bit complicated to analyze these antidrug antibodies,” Brun said. “There’s no consensus on what calibrators to use, and there’s no standardization of how to report the results, so you can’t really compare results from different assays. You need to know what your laboratory is using and how to interpret results from that particular assay, so that’s a challenge.”

Variability in drug tolerance also exists across assays, Wallace noted. “One of the challenges that have come up in the discussion of therapeutic drug monitoring is understanding what the target level is,” he said. “Defining what the target level might be for a specific condition is not something that’s well understood.”

Breaking down the science, he noted that an ADA can bind to a monoclonal antibody, forming an immune complex that avoids detection. Drug-sensitive assays may detect high concentrations of ADAs but miss low or moderate concentrations. Drug-tolerant assays may be more likely to detect low concentrations at ADAs, but the clinical significance is unclear.
 

Cost and Patient Trust as Barriers

“The costs vary a lot from assay to assay,” Brun said. “Some commercial assays can be really expensive.” In Norway, a dedicated lab with its own in-house assays helps to keep costs down, she said.

But that’s not the case in the United States, where insurance coverage can be a question mark, Shivani Garg, MD, a rheumatologist at the University of Wisconsin (UW)-Madison and director of the UW-Madison Health Lupus and Lupus Nephritis Clinics, told Medscape Medical News. “A lot of insurances are covering therapeutic drug monitoring, but for the high-deductible plans, there should be a way to offer these important tests to patients at a lower cost or figure out a way for coverage for those patients so that they can show that there are benefits of therapeutic drug monitoring without being sent a really big bill,” she said.

UW Health

Who May Benefit Most From TDM?

In the NOR-DRUM trials, patients at risk of developing ADA early on, before a disease flare or infusion reaction, seemed to benefit most from TDM. But who are those patients?

“We looked at risk factors for developing antidrug antibodies, and we found that patients with high disease activity when starting treatment, smokers, and patients with rheumatoid arthritis had a higher risk than other patients, as did patients who are not using concomitant immunosuppressive therapy,” Brun said.

“During treatment, we also found that low serum drug levels and drug holidays above 11 weeks were also risk factors,” she added.

The NOR-DRUM researchers also evaluated genetic risk factors and found that patients with the HLA-DQ2 gene variant were also at increased risk of developing ADA.

While NOR-DRUM evaluated only infliximab, some of its lessons may be applied to other DMARDs, Brun said. “We think that for other subcutaneously administered TNF inhibitors, you would probably see the same effect of proactive TDM, but we currently do not have data on that,” she said. A study similar to the NOR-DRUM design will evaluate this in Norway, Brun added.

She explained why the findings with infliximab may extend to adalimumab, which may be the second most immunogenic TNF inhibitor after infliximab. “The administration is different; it’s administered more often than infliximab; that would also make the results more uncertain to generalize to the other treatments, but I would guess there are also benefits of using TDM in other treatments.”
 

Potential Risks for TDM

Wallace has noted that TDM, with the current state of evidence, carries a number of potential risks. “The potential risks might be that you unnecessarily discontinue a medication because you detected an antibody, or the level seems low and you’re not able to get it higher, but the patient is otherwise doing fine,” he said. “You might end up increasing doses of the medicine that would put the patient at potentially increased risk of infection, as well as obviously more costs.”

That would also lead to more utilization of resources and costs, he said. “Some of those reasons are why there has been hesitation with therapeutic drug monitoring,” Wallace added.

A number of questions also surround the use of biosimilars and ADA levels, Wallace said. While a review of clinical trials found no meaningful differences in terms of immunogenicity between biosimilars and reference products, it did note discrepancies in how the agents were evaluated.
 

What DMARDs Are Most Suitable for TDM?

Petri said TDM would be useful for monitoring patients on mycophenolate mofetil. “A trough level can at least tell us if a patient is taking it,” she said. “Tacrolimus, used for lupus nephritis, has well-accepted peak and trough trends due to widespread use in transplant.”

Drugs with a wide variability in pharmacokinetics may also be suitable for TDM, Balevic said. That would include hydroxychloroquine, azathioprine, mycophenolate, or even cyclophosphamide. Drugs that have a narrow therapeutic index, such as tacrolimus, cyclosporine, or again, cyclophosphamide, might also be amenable to TDM, he said.
 

Why Do TDM?

“The two main reasons why somebody would go on to detect drug levels: The first may be to assess medication adherence, and this applies virtually to any drug that rheumatologists use; the second reason is to optimize dozing, either for efficacy purposes or to prevent toxicity,” Balevic said.

“When it comes to optimizing dosing, you should really think about TDM as one tool in our toolbelt,” he said.

Dose is “just a surrogate,” he said. “When we prescribe a drug, what truly matters is the amount of active unbound drug at the site of action. That’s what’s responsible for a drug’s pharmacologic effect.”

However, the same dose, or even the same weight-based dose, does not necessarily mean similar patients will achieve the same amount of exposure to the drug, but TDM can help determine that, he said.
 

What’s Next

Studies into the use of TDM in rheumatology are ongoing. Brun said her group is currently conducting a cost-effective analysis from the NOR-DRUM trials.

“There’s going to be more studies coming out in the next few years, looking at what impact the use of therapeutic drug monitoring might have on outcomes,” Wallace said.

“As we accumulate more and more evidence, we might see organizations like ACR and EULAR start to weigh in more on whether or not therapeutic drug monitoring can or should be used.”

Petri, Brun, and Garg had no relevant disclosures. Wallace disclosed financial relationships with Amgen, Alexion, BioCryst, Boehringer Ingelheim, Bristol Myers Squibb, Medpace, Novartis, Sanofi, Viela Bio, Visterra, Xencor, and Zenas. Balevic disclosed relationships with the National Institutes of Health, the Childhood Arthritis and Rheumatology Research Alliance, and UCB.
 

A version of this article appeared on Medscape.com.

Therapeutic drug monitoring (TDM) — the practice of using laboratory testing to measure blood levels of drugs — has garnered growing interest among rheumatologists in managing patients on disease-modifying antirheumatic drugs (DMARDs), but that hasn’t exactly translated to widespread practice.

While TDM has made some inroads with patients taking monoclonal antibodies, specifically infliximab, its uptake has encountered a number of headwinds, not the least of which is a lack of evidence and clinical guidelines, uneven access and standards of assays, and even an uncertainty about how to interpret laboratory results.

“In some fields, such as neurology, TDM is accepted for antiepileptics,” Michelle Petri, MD, MPH, director of the Johns Hopkins Lupus Center, Baltimore, told Medscape Medical News. “In rheumatology, though, TDM is underutilized and not adequately championed by the American College of Rheumatology.”

Johns Hopkins University

Duke University

Reactive vs Proactive TDM

Among the few trials that examined TDM in rheumatology patients are the NOR-DRUM A and B trials in Norway. Marthe Brun, MD, PhD, a rheumatologist at the Center for Treatment of Rheumatic and Musculoskeletal Diseases at Diakonhjemmet Hospital in Oslo, Norway, and a coauthor of the NOR-DRUM trials, told Medscape Medical News that the trials found an overall benefit to TDM during infliximab maintenance therapy. The trials included not only patients with inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, and spondyloarthritis) but also patients with inflammatory bowel disease and psoriasis, Brun said.

Nicolas Tourrenc

Brun explained that two types of TDM exist: Reactive and proactive. “Reactive TDM is when you use it to find the reason for a patient having a flare or disease worsening,” she told Medscape Medical News. “Proactive TDM would be regular testing to keep a patient within a therapeutic range to avoid flare because of low drug concentrations.”

Gastroenterologists are more inclined than rheumatologists and dermatologists to use reactive TDM, she said. “There have been no recommendations regarding proactive TDM because of the lack of data.”

In Europe, Wallace noted that European Alliance of Associations for Rheumatology (EULAR) recommendations consider the use of TDM in specific clinical scenarios, such as when treatment fails or to evaluate immunogenicity of a reaction, but they are limited. The American College of Rheumatology (ACR) does not have any recommendations for the use of TDM.

Based on the NOR-DRUM trials, rheumatologists in Norway have published their own guidelines for TDM for infliximab in rheumatologic disease, but they are in Norwegian and have not yet been taken up by EULAR, Brun noted. Publication of those recommendations in English is pending, she said.

“But for other subcutaneously administered TNF inhibitors, there’s a lack of data,” Brun added.
 

The State of the Evidence

NOR-DRUM A did not support the use of proactive TDM in the 30-week induction period as a way to improve disease remission in patients with chronic immune-mediated inflammatory disease. NOR-DRUM B, which evaluated TDM over a year, found the approach was more likely to lead to sustained disease control for that period.

Brun’s group recently published an analysis of the trials. “We did not find an overall effect during the initial phase of the treatment, the first 30 weeks,” she told Medscape Medical News.

“Then we looked at subgroups, and we found that the patients that developed antidrug antibodies [ADAs] had an effect, and ADA are associated with poorer outcomes as well as infusion reactions for patients treated with infliximab.

“So, it’s probably a benefit to be able to detect these ADA early before the patient experiences a disease flare or infusion reaction,” Brun added. “It facilitates for the clinician to take action to, for example, increase the dosing or switch therapy.”

However, the quality of the data supporting TDM in rheumatology is limited, Balevic said. “There’s very good observational data, but we have very few clinical trials that actually leverage TDM,” he said.

NOR-DRUM is the exception, he said. “Ideally, we need more of these dose-optimization trials to help guide clinical practice,” he said. But it stands alone.

Wallace noted several take-home messages from the NOR-DRUM trials, namely that using TDM to prevent ADA may be more effective during the maintenance phase of treatment than the induction phase. However, he said, the evidence is still emerging.

“It’s reasonable to say that we’re at an early stage of the evidence,” he said. “If you look at the large trials that have been done in rheumatology, they’ve combined patients with many different types of conditions, and a lot of our recommendations in rheumatology are disease-specific — in rheumatoid arthritis, in vasculitis. There’s a lack of data in specific diseases to guide or examine what the role of TDM might be.”

In the meantime, no fewer than four clinical trials evaluating TDM with tumor necrosis factor (TNF) inhibitors in rheumatologic diseases are ongoing or have completed but not yet released results, according to Wallace. Three Adalimumab Drug Optimization in Rheumatoid Arthritis trials are underway: The first is evaluating drug tapering vs disease activity score; the second is testing low or usual drug concentration; and the third is studying switches to etanercept or a non-TNF inhibitor drug (abatacept, rituximab, tocilizumab, or sarilumab) in patients failing treatment. Another trial called Tocilizumab Drug Levels to Optimized Treatment in RA is randomizing patients with high drug levels to dose maintenance or dose reduction. All four trials are sponsored by the Reade Rheumatology Research Institute, Amsterdam, the Netherlands.

Until clearer answers emerge from clinical trials, a number of barriers to and questions about the potential for TDM in rheumatology persist.
 

Barriers to Wider Use of TDM

“The biggest barrier with TDM is simply just a lack of what to do with the data,” Balevic said. “The clinician needs clear-cut guidance on what to do with the drug level. So, in other words, what is the target concentration for the drug? And if that target is not the goal, how should that dose be adjusted?”

The optimal drug levels, particularly for the older conventional synthetic DMARDs, simply have not been validated by clinical trials, he said.

“Different studies may report different target drug levels, and this could be due to different underlying population, or a different matrix — a measure of whole blood vs plasma — or even the timing of the sample,” he said. Balevic led a pharmacokinetic study earlier this year that proposed an algorithm for determining the number of missed hydroxychloroquine doses.

“This really goes back to the clinician needing to draw on a lot of pharmacology training to interpret the literature,” Balevic added.

That gets to the need for more education among rheumatologists, as Brun pointed out. “The physician needs to be educated about therapeutic ranges, when to assess concentrations of drug antibodies, and how to react to the results,” Brun said.

Which ADAs to identify is also problematic. “For antidrug antibodies, it’s especially challenging because there are so many assay formats in use, and it’s a bit complicated to analyze these antidrug antibodies,” Brun said. “There’s no consensus on what calibrators to use, and there’s no standardization of how to report the results, so you can’t really compare results from different assays. You need to know what your laboratory is using and how to interpret results from that particular assay, so that’s a challenge.”

Variability in drug tolerance also exists across assays, Wallace noted. “One of the challenges that have come up in the discussion of therapeutic drug monitoring is understanding what the target level is,” he said. “Defining what the target level might be for a specific condition is not something that’s well understood.”

Breaking down the science, he noted that an ADA can bind to a monoclonal antibody, forming an immune complex that avoids detection. Drug-sensitive assays may detect high concentrations of ADAs but miss low or moderate concentrations. Drug-tolerant assays may be more likely to detect low concentrations at ADAs, but the clinical significance is unclear.
 

Cost and Patient Trust as Barriers

“The costs vary a lot from assay to assay,” Brun said. “Some commercial assays can be really expensive.” In Norway, a dedicated lab with its own in-house assays helps to keep costs down, she said.

But that’s not the case in the United States, where insurance coverage can be a question mark, Shivani Garg, MD, a rheumatologist at the University of Wisconsin (UW)-Madison and director of the UW-Madison Health Lupus and Lupus Nephritis Clinics, told Medscape Medical News. “A lot of insurances are covering therapeutic drug monitoring, but for the high-deductible plans, there should be a way to offer these important tests to patients at a lower cost or figure out a way for coverage for those patients so that they can show that there are benefits of therapeutic drug monitoring without being sent a really big bill,” she said.

UW Health

Who May Benefit Most From TDM?

In the NOR-DRUM trials, patients at risk of developing ADA early on, before a disease flare or infusion reaction, seemed to benefit most from TDM. But who are those patients?

“We looked at risk factors for developing antidrug antibodies, and we found that patients with high disease activity when starting treatment, smokers, and patients with rheumatoid arthritis had a higher risk than other patients, as did patients who are not using concomitant immunosuppressive therapy,” Brun said.

“During treatment, we also found that low serum drug levels and drug holidays above 11 weeks were also risk factors,” she added.

The NOR-DRUM researchers also evaluated genetic risk factors and found that patients with the HLA-DQ2 gene variant were also at increased risk of developing ADA.

While NOR-DRUM evaluated only infliximab, some of its lessons may be applied to other DMARDs, Brun said. “We think that for other subcutaneously administered TNF inhibitors, you would probably see the same effect of proactive TDM, but we currently do not have data on that,” she said. A study similar to the NOR-DRUM design will evaluate this in Norway, Brun added.

She explained why the findings with infliximab may extend to adalimumab, which may be the second most immunogenic TNF inhibitor after infliximab. “The administration is different; it’s administered more often than infliximab; that would also make the results more uncertain to generalize to the other treatments, but I would guess there are also benefits of using TDM in other treatments.”
 

Potential Risks for TDM

Wallace has noted that TDM, with the current state of evidence, carries a number of potential risks. “The potential risks might be that you unnecessarily discontinue a medication because you detected an antibody, or the level seems low and you’re not able to get it higher, but the patient is otherwise doing fine,” he said. “You might end up increasing doses of the medicine that would put the patient at potentially increased risk of infection, as well as obviously more costs.”

That would also lead to more utilization of resources and costs, he said. “Some of those reasons are why there has been hesitation with therapeutic drug monitoring,” Wallace added.

A number of questions also surround the use of biosimilars and ADA levels, Wallace said. While a review of clinical trials found no meaningful differences in terms of immunogenicity between biosimilars and reference products, it did note discrepancies in how the agents were evaluated.
 

What DMARDs Are Most Suitable for TDM?

Petri said TDM would be useful for monitoring patients on mycophenolate mofetil. “A trough level can at least tell us if a patient is taking it,” she said. “Tacrolimus, used for lupus nephritis, has well-accepted peak and trough trends due to widespread use in transplant.”

Drugs with a wide variability in pharmacokinetics may also be suitable for TDM, Balevic said. That would include hydroxychloroquine, azathioprine, mycophenolate, or even cyclophosphamide. Drugs that have a narrow therapeutic index, such as tacrolimus, cyclosporine, or again, cyclophosphamide, might also be amenable to TDM, he said.
 

Why Do TDM?

“The two main reasons why somebody would go on to detect drug levels: The first may be to assess medication adherence, and this applies virtually to any drug that rheumatologists use; the second reason is to optimize dozing, either for efficacy purposes or to prevent toxicity,” Balevic said.

“When it comes to optimizing dosing, you should really think about TDM as one tool in our toolbelt,” he said.

Dose is “just a surrogate,” he said. “When we prescribe a drug, what truly matters is the amount of active unbound drug at the site of action. That’s what’s responsible for a drug’s pharmacologic effect.”

However, the same dose, or even the same weight-based dose, does not necessarily mean similar patients will achieve the same amount of exposure to the drug, but TDM can help determine that, he said.
 

What’s Next

Studies into the use of TDM in rheumatology are ongoing. Brun said her group is currently conducting a cost-effective analysis from the NOR-DRUM trials.

“There’s going to be more studies coming out in the next few years, looking at what impact the use of therapeutic drug monitoring might have on outcomes,” Wallace said.

“As we accumulate more and more evidence, we might see organizations like ACR and EULAR start to weigh in more on whether or not therapeutic drug monitoring can or should be used.”

Petri, Brun, and Garg had no relevant disclosures. Wallace disclosed financial relationships with Amgen, Alexion, BioCryst, Boehringer Ingelheim, Bristol Myers Squibb, Medpace, Novartis, Sanofi, Viela Bio, Visterra, Xencor, and Zenas. Balevic disclosed relationships with the National Institutes of Health, the Childhood Arthritis and Rheumatology Research Alliance, and UCB.
 

A version of this article appeared on Medscape.com.

Key clinical point: The presence of clinical or subclinical dactylitis represented a more active and severe form of psoriatic arthritis (PsA), characterized by increased disease activity, swollen joint counts (SJCs), and tender joint counts (TJCs).

Major finding: PsA with dactylitis (clinical or subclinical) vs without dactylitis was associated with higher median disease activity index in PsA (DAPSA) scores (25.5 vs 16.1; P < .01), SJCs (4 vs 2; P < .001), and TJCs (4 vs 3; P < .01). PsA with subclinical dactylitis vs without dactylitis was associated with even higher DAPSA scores (27.2 vs 16.1; P < .05), SJCs (4.5 vs 2; P < .01), and TJCs (5 vs 3; P < .05).

Study details: This case-control study included 223 patients with PsA who were stratified on the basis of the presence of dactylitis (clinical or subclinical) or its absence at baseline.

Disclosures: This study was supported by the Youth Clinical Research Project of Peking University First Hospital and other sources. No conflicts of interest were reported.

Source: Song Z, Geng Y, Zhang X, Deng X, Zhang Z. Subclinical dactylitis represents a more active phenotype of psoriatic arthritis. Joint Bone Spine. Published online September 24, 2024. Source

Key clinical point: The presence of clinical or subclinical dactylitis represented a more active and severe form of psoriatic arthritis (PsA), characterized by increased disease activity, swollen joint counts (SJCs), and tender joint counts (TJCs).

Major finding: PsA with dactylitis (clinical or subclinical) vs without dactylitis was associated with higher median disease activity index in PsA (DAPSA) scores (25.5 vs 16.1; P < .01), SJCs (4 vs 2; P < .001), and TJCs (4 vs 3; P < .01). PsA with subclinical dactylitis vs without dactylitis was associated with even higher DAPSA scores (27.2 vs 16.1; P < .05), SJCs (4.5 vs 2; P < .01), and TJCs (5 vs 3; P < .05).

Study details: This case-control study included 223 patients with PsA who were stratified on the basis of the presence of dactylitis (clinical or subclinical) or its absence at baseline.

Disclosures: This study was supported by the Youth Clinical Research Project of Peking University First Hospital and other sources. No conflicts of interest were reported.

Source: Song Z, Geng Y, Zhang X, Deng X, Zhang Z. Subclinical dactylitis represents a more active phenotype of psoriatic arthritis. Joint Bone Spine. Published online September 24, 2024. Source

Key clinical point: The presence of clinical or subclinical dactylitis represented a more active and severe form of psoriatic arthritis (PsA), characterized by increased disease activity, swollen joint counts (SJCs), and tender joint counts (TJCs).

Major finding: PsA with dactylitis (clinical or subclinical) vs without dactylitis was associated with higher median disease activity index in PsA (DAPSA) scores (25.5 vs 16.1; P < .01), SJCs (4 vs 2; P < .001), and TJCs (4 vs 3; P < .01). PsA with subclinical dactylitis vs without dactylitis was associated with even higher DAPSA scores (27.2 vs 16.1; P < .05), SJCs (4.5 vs 2; P < .01), and TJCs (5 vs 3; P < .05).

Study details: This case-control study included 223 patients with PsA who were stratified on the basis of the presence of dactylitis (clinical or subclinical) or its absence at baseline.

Disclosures: This study was supported by the Youth Clinical Research Project of Peking University First Hospital and other sources. No conflicts of interest were reported.

Source: Song Z, Geng Y, Zhang X, Deng X, Zhang Z. Subclinical dactylitis represents a more active phenotype of psoriatic arthritis. Joint Bone Spine. Published online September 24, 2024. Source

Key clinical point: Guselkumab administered every 4 weeks (Q4W) or every 8 weeks (Q8W) yielded better clinical outcomes than placebo in patients with psoriatic arthritis (PsA), without any new safety concerns.

Major findings: At week 24, a higher proportion of patients receiving guselkumab Q4W (60%) and Q8W (51%) vs placebo (30%) achieved a ≥ 20% improvement in the American College of Rheumatology (ACR)20 response. The response rates increased through week 52 (69%-78) and were consistent at week 100 (76%-80%) across all the groups. Similar trends were observed for ACR50, with no new safety signals.

Study details: This post hoc analysis of the phase 3 trials DISCOVER-1 and DISCOVER-2 included 1002 biologic-naive patients with PsA who received 100 mg guselkumab Q4W, 100 mg guselkumab at weeks 0 and 4 and then Q8W, or placebo through week 24 with crossover to 100 mg guselkumab Q4W.

Disclosure: The study was sponsored by Janssen-Cilag Ltd. Four authors were employees of Johnson & Johnson. Several authors received research grants, consulting fees, or had ties with various sources.

Source: Mease P, Korotaeva T, Shesternya P, et al. Guselkumab in biologic-naïve patients with active psoriatic arthritis in Russia: A post hoc analysis of the DISCOVER-1 and -2 randomized clinical trials. Rheumatol Ther. Published online September 25, 2024. Source

Key clinical point: Guselkumab administered every 4 weeks (Q4W) or every 8 weeks (Q8W) yielded better clinical outcomes than placebo in patients with psoriatic arthritis (PsA), without any new safety concerns.

Major findings: At week 24, a higher proportion of patients receiving guselkumab Q4W (60%) and Q8W (51%) vs placebo (30%) achieved a ≥ 20% improvement in the American College of Rheumatology (ACR)20 response. The response rates increased through week 52 (69%-78) and were consistent at week 100 (76%-80%) across all the groups. Similar trends were observed for ACR50, with no new safety signals.

Study details: This post hoc analysis of the phase 3 trials DISCOVER-1 and DISCOVER-2 included 1002 biologic-naive patients with PsA who received 100 mg guselkumab Q4W, 100 mg guselkumab at weeks 0 and 4 and then Q8W, or placebo through week 24 with crossover to 100 mg guselkumab Q4W.

Disclosure: The study was sponsored by Janssen-Cilag Ltd. Four authors were employees of Johnson & Johnson. Several authors received research grants, consulting fees, or had ties with various sources.

Source: Mease P, Korotaeva T, Shesternya P, et al. Guselkumab in biologic-naïve patients with active psoriatic arthritis in Russia: A post hoc analysis of the DISCOVER-1 and -2 randomized clinical trials. Rheumatol Ther. Published online September 25, 2024. Source

Key clinical point: Guselkumab administered every 4 weeks (Q4W) or every 8 weeks (Q8W) yielded better clinical outcomes than placebo in patients with psoriatic arthritis (PsA), without any new safety concerns.

Major findings: At week 24, a higher proportion of patients receiving guselkumab Q4W (60%) and Q8W (51%) vs placebo (30%) achieved a ≥ 20% improvement in the American College of Rheumatology (ACR)20 response. The response rates increased through week 52 (69%-78) and were consistent at week 100 (76%-80%) across all the groups. Similar trends were observed for ACR50, with no new safety signals.

Study details: This post hoc analysis of the phase 3 trials DISCOVER-1 and DISCOVER-2 included 1002 biologic-naive patients with PsA who received 100 mg guselkumab Q4W, 100 mg guselkumab at weeks 0 and 4 and then Q8W, or placebo through week 24 with crossover to 100 mg guselkumab Q4W.

Disclosure: The study was sponsored by Janssen-Cilag Ltd. Four authors were employees of Johnson & Johnson. Several authors received research grants, consulting fees, or had ties with various sources.

Source: Mease P, Korotaeva T, Shesternya P, et al. Guselkumab in biologic-naïve patients with active psoriatic arthritis in Russia: A post hoc analysis of the DISCOVER-1 and -2 randomized clinical trials. Rheumatol Ther. Published online September 25, 2024. Source

Key clinical point: In patients with psoriatic arthritis (PsA), tofacitinib demonstrated higher efficacy than placebo, regardless of smoking status; however, current or past smokers experienced increased rates of adverse events.

Major finding: At 3 months, 10 mg tofacitinib showed higher rates of a ≥ 50% improvement in the American College of Rheumatology response than placebo in current or past smokers (odds ratio [OR], 3.01; 95% CI, 1.43-6.33) and never smokers (OR, 6.53; 95% CI, 3.46-12.33). The incidence rates of treatment-emergent adverse events were higher in current or past smokers vs never smokers (adjusted incidence rate, 263.2 vs 208.9); 5 mg tofacitinib had comparable outcomes.

Study details: This post hoc analysis pooled data from phase 2 and 3 trials and a long-term extension study, involving 914 patients with PsA and 372 patients with ankylosing spondylitis who received tofacitinib (5 or 10 mg twice daily) or placebo, while considering their smoking status.

Disclosures: This study was sponsored by Pfizer. Four authors declared being current or former employees or shareholders of Pfizer. Other authors declared having ties with various sources.

Source: Ogdie A, Kristensen LE, Soriano ER, et al. Efficacy and safety of tofacitinib in patients with psoriatic arthritis or ankylosing spondylitis by cigarette smoking status. Rheumatol Ther. Published online September 25, 2024. Source

Key clinical point: In patients with psoriatic arthritis (PsA), tofacitinib demonstrated higher efficacy than placebo, regardless of smoking status; however, current or past smokers experienced increased rates of adverse events.

Major finding: At 3 months, 10 mg tofacitinib showed higher rates of a ≥ 50% improvement in the American College of Rheumatology response than placebo in current or past smokers (odds ratio [OR], 3.01; 95% CI, 1.43-6.33) and never smokers (OR, 6.53; 95% CI, 3.46-12.33). The incidence rates of treatment-emergent adverse events were higher in current or past smokers vs never smokers (adjusted incidence rate, 263.2 vs 208.9); 5 mg tofacitinib had comparable outcomes.

Study details: This post hoc analysis pooled data from phase 2 and 3 trials and a long-term extension study, involving 914 patients with PsA and 372 patients with ankylosing spondylitis who received tofacitinib (5 or 10 mg twice daily) or placebo, while considering their smoking status.

Disclosures: This study was sponsored by Pfizer. Four authors declared being current or former employees or shareholders of Pfizer. Other authors declared having ties with various sources.

Source: Ogdie A, Kristensen LE, Soriano ER, et al. Efficacy and safety of tofacitinib in patients with psoriatic arthritis or ankylosing spondylitis by cigarette smoking status. Rheumatol Ther. Published online September 25, 2024. Source

Key clinical point: In patients with psoriatic arthritis (PsA), tofacitinib demonstrated higher efficacy than placebo, regardless of smoking status; however, current or past smokers experienced increased rates of adverse events.

Major finding: At 3 months, 10 mg tofacitinib showed higher rates of a ≥ 50% improvement in the American College of Rheumatology response than placebo in current or past smokers (odds ratio [OR], 3.01; 95% CI, 1.43-6.33) and never smokers (OR, 6.53; 95% CI, 3.46-12.33). The incidence rates of treatment-emergent adverse events were higher in current or past smokers vs never smokers (adjusted incidence rate, 263.2 vs 208.9); 5 mg tofacitinib had comparable outcomes.

Study details: This post hoc analysis pooled data from phase 2 and 3 trials and a long-term extension study, involving 914 patients with PsA and 372 patients with ankylosing spondylitis who received tofacitinib (5 or 10 mg twice daily) or placebo, while considering their smoking status.

Disclosures: This study was sponsored by Pfizer. Four authors declared being current or former employees or shareholders of Pfizer. Other authors declared having ties with various sources.

Source: Ogdie A, Kristensen LE, Soriano ER, et al. Efficacy and safety of tofacitinib in patients with psoriatic arthritis or ankylosing spondylitis by cigarette smoking status. Rheumatol Ther. Published online September 25, 2024. Source

Key clinical point: In patients with active psoriatic arthritis (PsA), intravenous secukinumab every 4 weeks demonstrated rapid and sustained efficacy, along with a safety profile consistent with that of subcutaneous secukinumab.

Major finding: At week 16, intravenous secukinumab vs placebo significantly improved the American College of Rheumatology 50 response rate (31.4% vs 6.3%; adjusted P < .0001). Improvements were observed as early as week 4 (P < .0005) and were sustained through week 52, regardless of whether patients continued intravenous secukinumab (58.0%) or switched from placebo to intravenous secukinumab (64.0%). No new safety signals were reported.

Study details: In this phase 3 INVIGORATE-2 trial, 381 patients with active PsA and either plaque psoriasis or nail psoriasis were randomly assigned to receive intravenous secukinumab or placebo with crossover to intravenous secukinumab at week 16.

Disclosures: This study was supported by Novartis. Five authors declared being employees of and owning stocks in Novartis. Several authors declared having ties with various sources, including Novartis.

Source: Kivitz A, Sedova L, Churchill M, et al. Efficacy and safety of intravenous secukinumab for the treatment of active psoriatic arthritis: Results from the randomized, placebo-controlled phase III INVIGORATE-2 study. Arthritis Rheumatol. Published online September 19, 2024. Source

Key clinical point: In patients with active psoriatic arthritis (PsA), intravenous secukinumab every 4 weeks demonstrated rapid and sustained efficacy, along with a safety profile consistent with that of subcutaneous secukinumab.

Major finding: At week 16, intravenous secukinumab vs placebo significantly improved the American College of Rheumatology 50 response rate (31.4% vs 6.3%; adjusted P < .0001). Improvements were observed as early as week 4 (P < .0005) and were sustained through week 52, regardless of whether patients continued intravenous secukinumab (58.0%) or switched from placebo to intravenous secukinumab (64.0%). No new safety signals were reported.

Study details: In this phase 3 INVIGORATE-2 trial, 381 patients with active PsA and either plaque psoriasis or nail psoriasis were randomly assigned to receive intravenous secukinumab or placebo with crossover to intravenous secukinumab at week 16.

Disclosures: This study was supported by Novartis. Five authors declared being employees of and owning stocks in Novartis. Several authors declared having ties with various sources, including Novartis.

Source: Kivitz A, Sedova L, Churchill M, et al. Efficacy and safety of intravenous secukinumab for the treatment of active psoriatic arthritis: Results from the randomized, placebo-controlled phase III INVIGORATE-2 study. Arthritis Rheumatol. Published online September 19, 2024. Source

Key clinical point: In patients with active psoriatic arthritis (PsA), intravenous secukinumab every 4 weeks demonstrated rapid and sustained efficacy, along with a safety profile consistent with that of subcutaneous secukinumab.

Major finding: At week 16, intravenous secukinumab vs placebo significantly improved the American College of Rheumatology 50 response rate (31.4% vs 6.3%; adjusted P < .0001). Improvements were observed as early as week 4 (P < .0005) and were sustained through week 52, regardless of whether patients continued intravenous secukinumab (58.0%) or switched from placebo to intravenous secukinumab (64.0%). No new safety signals were reported.

Study details: In this phase 3 INVIGORATE-2 trial, 381 patients with active PsA and either plaque psoriasis or nail psoriasis were randomly assigned to receive intravenous secukinumab or placebo with crossover to intravenous secukinumab at week 16.

Disclosures: This study was supported by Novartis. Five authors declared being employees of and owning stocks in Novartis. Several authors declared having ties with various sources, including Novartis.

Source: Kivitz A, Sedova L, Churchill M, et al. Efficacy and safety of intravenous secukinumab for the treatment of active psoriatic arthritis: Results from the randomized, placebo-controlled phase III INVIGORATE-2 study. Arthritis Rheumatol. Published online September 19, 2024. Source

Key clinical point: In biologic-naive patients with active psoriatic arthritis (PsA), guselkumab administered every 8 weeks (Q8W) led to consistent patient-level improvements in joint disease activity, which persisted for 2 years.

Major finding: Guselkumab maintained high rates of minimal clinically important improvements (MCII) in the clinical Disease Activity Index for PsA (cDAPSA; 94%-99%), with improvements of ≥ 5.7 from baseline through week 52 with a dosing of 100 mg guselkumab Q8W. Among those achieving MCII by week 24, maintenance rates were 69.2% for the cDAPSA and 89.0% for the Psoriatic Arthritis Disease Activity Score at 100 weeks post-achievement.

Study details: This post hoc analysis of the phase 3 DISCOVER-2 trial included 248 biologic-naive patients with active PsA who received 100 mg guselkumab Q8W for 100 weeks.

Disclosures: This study was supported by Janssen Research & Development, LLC. Several authors disclosed holding stock or stock options; receiving grants, payment, honoraria, or consulting fees; or having other ties with various sources, including Janssen.

Source: Mease PJ, Baraliakos X, Chandran V, et al. Persistent patient-level effect of guselkumab at consecutive 8-week dosing visits and over time in patients with active psoriatic arthritis: Post hoc analysis of a 2-year, phase 3, randomized, controlled study. ACR Open Rheumatol. Published online October 4, 2024. Source

Key clinical point: In biologic-naive patients with active psoriatic arthritis (PsA), guselkumab administered every 8 weeks (Q8W) led to consistent patient-level improvements in joint disease activity, which persisted for 2 years.

Major finding: Guselkumab maintained high rates of minimal clinically important improvements (MCII) in the clinical Disease Activity Index for PsA (cDAPSA; 94%-99%), with improvements of ≥ 5.7 from baseline through week 52 with a dosing of 100 mg guselkumab Q8W. Among those achieving MCII by week 24, maintenance rates were 69.2% for the cDAPSA and 89.0% for the Psoriatic Arthritis Disease Activity Score at 100 weeks post-achievement.

Study details: This post hoc analysis of the phase 3 DISCOVER-2 trial included 248 biologic-naive patients with active PsA who received 100 mg guselkumab Q8W for 100 weeks.

Disclosures: This study was supported by Janssen Research & Development, LLC. Several authors disclosed holding stock or stock options; receiving grants, payment, honoraria, or consulting fees; or having other ties with various sources, including Janssen.

Source: Mease PJ, Baraliakos X, Chandran V, et al. Persistent patient-level effect of guselkumab at consecutive 8-week dosing visits and over time in patients with active psoriatic arthritis: Post hoc analysis of a 2-year, phase 3, randomized, controlled study. ACR Open Rheumatol. Published online October 4, 2024. Source

Key clinical point: In biologic-naive patients with active psoriatic arthritis (PsA), guselkumab administered every 8 weeks (Q8W) led to consistent patient-level improvements in joint disease activity, which persisted for 2 years.

Major finding: Guselkumab maintained high rates of minimal clinically important improvements (MCII) in the clinical Disease Activity Index for PsA (cDAPSA; 94%-99%), with improvements of ≥ 5.7 from baseline through week 52 with a dosing of 100 mg guselkumab Q8W. Among those achieving MCII by week 24, maintenance rates were 69.2% for the cDAPSA and 89.0% for the Psoriatic Arthritis Disease Activity Score at 100 weeks post-achievement.

Study details: This post hoc analysis of the phase 3 DISCOVER-2 trial included 248 biologic-naive patients with active PsA who received 100 mg guselkumab Q8W for 100 weeks.

Disclosures: This study was supported by Janssen Research & Development, LLC. Several authors disclosed holding stock or stock options; receiving grants, payment, honoraria, or consulting fees; or having other ties with various sources, including Janssen.

Source: Mease PJ, Baraliakos X, Chandran V, et al. Persistent patient-level effect of guselkumab at consecutive 8-week dosing visits and over time in patients with active psoriatic arthritis: Post hoc analysis of a 2-year, phase 3, randomized, controlled study. ACR Open Rheumatol. Published online October 4, 2024. Source

Key clinical point: Secukinumab led to clinical improvements across all psoriatic arthritis (PsA) domains, achieving minimal disease activity and demonstrating a favorable 4-year safety profile in biologic-naive patients, those with previous treatment failure, and those with or without comorbidities.

Major finding: During the 48-month follow-up, secukinumab significantly reduced the proportion of patients with active tender joints, swollen joints, enthesitis, and dactylitis (all P < .01). Overall, 50% of patients achieved remission or low disease activity in PsA, with higher rates of minimal disease activity in biologic-naive vs non-naive patients (76.9% vs 66.2%; P < .01) and in those without comorbidities vs those with over three comorbidities (78.8% vs 48.7%; P < .001). Only 5.9% of patients discontinued treatment due to adverse events.

Study details: This 4-year prospective observational study included 685 patients with PsA who received secukinumab; 32.9% were biologic-naive and 74.2% had at least one comorbidity.

Disclosures: This study did not receive financial support from any pharmaceutical company. The authors declared no conflicts of interest.

Source: Ramonda R, Lorenzin M, Chimenti MS, et al. Four-year effectiveness, safety and drug retention rate of secukinumab in psoriatic arthritis: A real-life Italian multicenter cohort. Arthritis Res Ther. 2024;26:172. Source

Key clinical point: Secukinumab led to clinical improvements across all psoriatic arthritis (PsA) domains, achieving minimal disease activity and demonstrating a favorable 4-year safety profile in biologic-naive patients, those with previous treatment failure, and those with or without comorbidities.

Major finding: During the 48-month follow-up, secukinumab significantly reduced the proportion of patients with active tender joints, swollen joints, enthesitis, and dactylitis (all P < .01). Overall, 50% of patients achieved remission or low disease activity in PsA, with higher rates of minimal disease activity in biologic-naive vs non-naive patients (76.9% vs 66.2%; P < .01) and in those without comorbidities vs those with over three comorbidities (78.8% vs 48.7%; P < .001). Only 5.9% of patients discontinued treatment due to adverse events.

Study details: This 4-year prospective observational study included 685 patients with PsA who received secukinumab; 32.9% were biologic-naive and 74.2% had at least one comorbidity.

Disclosures: This study did not receive financial support from any pharmaceutical company. The authors declared no conflicts of interest.

Source: Ramonda R, Lorenzin M, Chimenti MS, et al. Four-year effectiveness, safety and drug retention rate of secukinumab in psoriatic arthritis: A real-life Italian multicenter cohort. Arthritis Res Ther. 2024;26:172. Source

Key clinical point: Secukinumab led to clinical improvements across all psoriatic arthritis (PsA) domains, achieving minimal disease activity and demonstrating a favorable 4-year safety profile in biologic-naive patients, those with previous treatment failure, and those with or without comorbidities.

Major finding: During the 48-month follow-up, secukinumab significantly reduced the proportion of patients with active tender joints, swollen joints, enthesitis, and dactylitis (all P < .01). Overall, 50% of patients achieved remission or low disease activity in PsA, with higher rates of minimal disease activity in biologic-naive vs non-naive patients (76.9% vs 66.2%; P < .01) and in those without comorbidities vs those with over three comorbidities (78.8% vs 48.7%; P < .001). Only 5.9% of patients discontinued treatment due to adverse events.

Study details: This 4-year prospective observational study included 685 patients with PsA who received secukinumab; 32.9% were biologic-naive and 74.2% had at least one comorbidity.

Disclosures: This study did not receive financial support from any pharmaceutical company. The authors declared no conflicts of interest.

Source: Ramonda R, Lorenzin M, Chimenti MS, et al. Four-year effectiveness, safety and drug retention rate of secukinumab in psoriatic arthritis: A real-life Italian multicenter cohort. Arthritis Res Ther. 2024;26:172. Source