AnaptysBio’s investigational drug, rosnilimab, has shown promising results in a Phase 2b trial for rheumatoid arthritis (RA). The drug demonstrated efficacy comparable to JAK inhibitors but with a better safety and tolerability profile, achieving significant reductions in disease activity and pain over six months. Furthermore, the drug’s effects were durable for at least two months after treatment cessation.
This news holds substantial potential for individuals with moderate-to-severe RA. Current treatment options often involve cycling through various therapies without achieving sustained low disease activity, a key factor in slowing disease progression. Rosnilimab’s efficacy, coupled with its monthly subcutaneous administration and favorable safety profile, offers a potential solution to this challenge. The durability of response also suggests the possibility of extended dosing intervals during maintenance, potentially improving patient adherence and quality of life.
In the 424-patient trial, rosnilimab demonstrated JAK-like efficacy in achieving low disease activity (LDA) and remission as measured by the Clinical Disease Activity Index (CDAI), as well as ACR70 response. By week 28, LDA rates ranged from 34% to 72% across different doses and patient subgroups (biologic/targeted synthetic DMARD-naïve or experienced). Importantly, the trial’s strict continuation criteria may underestimate the true efficacy, as patients showing significant improvement were excluded from the later stages of the study. The safety data was encouraging, with no treatment-related serious adverse events, malignancies, or systemic hypersensitivity reported. Adverse events were generally mild to moderate, with a low discontinuation rate due to adverse events. Translational data further supports the clinical findings, indicating rosnilimab’s distinct mechanism of action in restoring immune homeostasis.
Rosnilimab’s positive Phase 2b results pave the way for further clinical development. The potential for a best-in-disease profile, combining efficacy with a favorable safety profile and convenient dosing, positions rosnilimab as a potential game-changer in the RA treatment landscape. Pending further clinical trials and regulatory approvals, this therapy could offer a new and improved treatment option for patients seeking long-term disease control and improved quality of life. The company is also conducting a Phase 2 study of rosnilimab in ulcerative colitis, with initial data expected in Q4 2025.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
