The overactive bladder treatment mirabegron (Myrbetriq) is one of three new drugs to be linked to cases of drug-associated antineutrophil cytoplasmic antibody–associated vasculitis (DA-AAV) according to pharmacovigilance data.
The other two drugs are the antiviral agent sofosbuvir (Sovaldi) and the tyrosine kinase inhibitor nintedanib (Ofev), which is indicated for chronic fibrosing interstitial lung diseases (ILDs) with a progressive phenotype.
The study findings also strengthen previously suspected associations, Arthritis & Rheumatology. This includes associations between hydralazine, propylthiouracil, thiamazole, minocycline, and carbimazole to name a few more of the 15 drugs where associations were found., of Caen (France) University Hospital and coauthors report in
“These data imply specific prescriber attention to these drugs and argue for experimental studies on AAV pathophysiology with [the] recent drugs,” Dr. Deshayes and colleagues wrote.
Identifying whether AAV could be due to drug treatment is important as there have been suggestions that this may confer a better prognosis than for primary AAV. In addition, “withdrawal of the culprit drug” may be enough to treat the patient in milder cases, the researchers suggested.
That said, the researchers acknowledged that it can be difficult to attribute AAV to a specific drug, particularly as data are often from case reports or small series of patients and, until now, research had considered older medications.
To update current knowledge and include newer treatments, Dr. Deshayes and associates took data from the World Health Organization pharmacovigilance database (VigiBase) and performed a retrospective analysis.
They collected data on all adverse drug reactions (ADRs) reported using the Medical Dictionary for Drug Regulatory Activities preferred term ‘anti-neutrophil’ cytoplasmic antibody positive vasculitis’ from its introduction in 2006 up until November 2020.
Drugs used in the management of AAV, such as azathioprine, cyclophosphamide, leflunomide, and methotrexate, among others, were not included in the analysis “due to potential indication bias,” they explained.
Among 483 individual “deduplicated” case safety reports, most cases of DA-AAV were reported in women (71.2% of cases) and the median age at onset was 62 years. The median time to develop AAV after drug initiation was 9 months.
DA-AAV was considered serious in almost all (98%) of the reported cases, meaning that it was life-threatening, had resulted in or had prolonged hospital treatment, caused significant or persistent disability or other anomalies such as birth defects, or resulted in the death of the individual. With regard to the latter, DA-AAV was reported as fatal in 8.9% of cases.
The highest rates of reported DA-AAV were seen in people treated with the antihypertensive drug hydralazine, the antithyroid drugs propylthiouracil, thiamazole, and carbimazole, the antibiotic minocycline, mirabegron, sofosbuvir, and nintedanib.
A further seven drugs were also linked to cases of AAV, bringing the total to list to 15 drugs associated with overreporting of AAV. This included the heavy metal antagonist penicillamine, the influenza vaccine, the gout medication allopurinol, the anti-tuberculosis drug rifampin, the antiviral agent peginterferon alfa-2b, the anti-asthma drug montelukast, and the anti-cholesterol agent rosuvastatin.
Dr. Deshayes and coauthors pointed out that the associations do not imply causality. The data mining approach used allowed for the “automated detection of drug safety signals associated with rare events such as AAV,” they said.
There are limitations, they acknowledged, which are common to studies that use pharmacovigilance data. For one, “notoriety bias” could be at play. This is where there is an “increased number of reports after safety alerts in the media.” Missing data, “including delay between the introduction of the drug and AAV,” could be a factor, as could “bias related to its retrospective and declarative design.”
The study received no commercial funding. All study authors declared no competing interests.