Safety
Abatacept’s known side effects include respiratory infections that are occasionally serious, allergic reactions and, very rarely, malignancies. Researchers identified no new safety concerns and found that adding abatacept to standard treatment was safe and generally well tolerated by trial patients.
During the double-blind period, the abatacept and placebo groups had similar rates of adverse events, including serious ones and events leading to discontinuation. Each group had four patients with serious adverse events. Infections occurred in 25.3% of abatacept patients and 42.5% of placebo patients. Serious infections occurred in 14.5% of abatacept patients and 6.3% of the switch group. No malignancies occurred in either group. One death in the placebo arm was due to an unexplained acute respiratory event.
During the open-label period, the observed safety profile was similar, the researchers report.
What’s Next
Despite promising results, the trial sponsor has decided to forgo regulatory approval for abatacept for non-DM patients, Dr. Aggarwal says.
Despite this decision, findings from the trial have advanced the field, Dr. Aggarwal maintains. “We have proved that targeting an interaction between B and T cells and preventing activation of the T cells gets efficacy in myositis and is safe,” he explains. “That means future novel therapies that target T cells or the interaction between B and T cells could be very lucrative in myositis.” This knowledge could be used to find other novel therapeutic targets.
In the meantime, as rheumatologists in both academic centers and general practices continue to see some patients with IIM, abatacept might help a portion of them. “Based on this trial, abatacept is a reasonable option for patients with myositis, especially necrotizing myopathy, once they are failing their initial lines of treatment,” Dr. Aggarwal notes.
Deborah Levenson is a writer and editor based in College Park, Md.
References
- Aggarwal R, Lundberg IE, Song YW, et al. Efficacy and safety of subcutaneous abatacept plus standard treatment for active idiopathic inflammatory myopathy: Phase III randomized, controlled trial. Arthritis Rheumatol, 2024 Nov 28, Online ahead of print.
- Tjärnlund A, Tang Q, Wick C, et al. Abatacept in the treatment of adult dermatomyositis and polymyositis: A randomised, phase IIb treatment delayed-start trial. Ann Rheum Dis. 2018 Jan;77(1):55-62.
Disclosures
Dr. Aggarwal has received grants or contracts from Boehringer Ingelheim, Bristol Myers Squibb, EMD Serono and Q32. He has received consulting fees from Actigraph, Alexion, ANI Pharmaceutical, Argenx, AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Cabaletta Bio, Capella, Corbus, CSL Behring, EMD Serono, Galapagos, Horizontal Therapeutics, I-Cell, Janssen, Kezar, Kyverna, Merck, Octapharma, Pfizer, Roivant, Sanofi and Teva.
