Two international phase 3 randomized trials ofaccording to reports published in the New England Journal of Medicine.
The Long-Acting Cabotegravir and Rilpivirine after Oral Induction for HIV-1 Infection (FLAIR) study and the Long-Acting Cabotegravir and Rilpivirine for Maintenance of HIV-1 Suppression (ATLAS) study looked at a separate facet of the use of a monthly therapeutic injection as a replacement for daily oral HIV therapy.
The FLAIR trial (ClinicalTrials.gov number,) was a phase 3, randomized, open-label study in which adults with HIV-1 infection who had not previously received antiretroviral therapy were given 20 weeks of daily oral induction therapy with dolutegravir–abacavir–lamivudine. Those patients with an HIV-1 RNA level of less than 50 copies per milliliter after 16 weeks were then randomly assigned (1:1) to continue their current oral therapy or switch to oral cabotegravir plus rilpivirine for 1 month followed by monthly intramuscular injections of long-acting cabotegravir, an HIV-1 integrase strand-transfer inhibitor, and rilpivirine, a nonnucleoside reverse-transcriptase inhibitor.
At week 48, an HIV-1 RNA level of 50 copies per milliliter or higher was found in 6 of 283 patients (2.1%) who received the long-acting therapy and in 7 of 283 (2.5%) who received oral therapy, which met the criterion for noninferiority for the primary endpoint. An HIV-1 RNA level of less than 50 copies per milliliter at week 48 was found in 93.6% of patients who received long-acting therapy and in 93.3% who received oral therapy, which also met the criterion for noninferiority, according topublished in the New England Journal of Medicine.
Injection site reactions were reported in 86% of the long-acting therapy patients, 4 of whom withdrew from the trial for injection-related reasons. Grade 3 or higher adverse events and events that met liver-related stopping criteria occurred in 11% and 2%, respectively, of those who received long-acting therapy and in 4% and 1% of those who received oral therapy.
An assessment of treatment satisfaction at 48 weeks showed that 91% of the patients who switched to long-acting therapy preferred it to their daily oral therapy.
The ATLAS trial (ClinicalTrials.gov number,) was a phase 3, open-label, multicenter, noninferiority trial involving patients who had plasma HIV-1 RNA levels of less than 50 copies per milliliter for at least 6 months while taking standard oral antiretroviral therapy. These patients were randomized (308 in each group) to the long-acting cabotegravir plus rilpivirine injection therapy or daily oral therapy.
At 48 weeks, HIV-1 RNA levels of 50 copies per milliliter or higher were found in five participants (1.6%) receiving long-acting therapy and in three (1.0%) receiving oral therapy, which met the criterion for noninferiority for the primary endpoint, according toreported in the New England Journal of Medicine.
HIV-1 RNA levels of less than 50 copies per milliliter at week 48 occurred in 92.5% of patients on long-acting therapy and in 95.5% of those receiving oral therapy, which also met the criterion for noninferiority for this endpoint. Three patients in the long-acting therapy group had virologic failure, compared with four participants who received oral therapy.
Adverse events were more common in the long-acting–therapy group and included injection-site pain, which occurred in 231 recipients (75%) of long-acting therapy. This was mild or moderate in most cases, according to the authors. However, 1% of the participants in this group withdrew because of it. Overall, serious adverse events were reported in no more than 5% of participants in each group.
Together, the ATLAS and the FLAIR trials show that long-acting intramuscular injection therapy is noninferior to oral therapy as both an early regimen for HIV treatment, as well as for later, maintenance dosing. The use of long-acting therapy may improve patient adherence to treatment, according to both sets of study authors.
The ATLAS and FLAIR trials were funded by ViiV Healthcare and Janssen. The authors of both studies reported ties to pharmaceutical associations, and some authors are employees of the two funding sources.