Phase III study of SAR 153191 (sarilumab) meets endpoints in rheumatoid arthritis- Sanofi/Regeneron Pharma

Sanofi and Regeneron Pharmaceuticals announced results from a pivotal Phase III study, SARIL-RA-TARGET, of SAR 153191 (sarilumab), showing the study met both its co-primary endpoints of improvements in signs and symptoms of rheumatoid arthritis (RA) and improvements in physical function, as well as secondary efficacy endpoints.

The co-primary endpoints were:

1. Improvement in physical function at week 12, as measured by mean change from baseline in the Health Assessment Questionnaire-Disability Index (HAQ-DI). The change from baseline to week 12 in HAQ-DI was -0.49, -0.50, and -0.29 in the sarilumab 200 mg, sarilumab 150 mg and placebo groups, respectively
2. Improvements in signs and symptoms of RA at week 24, as measured by the proportion of patients achieving an ACR20 response. These were 61% in the sarilumab 200 mg group; 56% in the sarilumab 150 mg group; and 34% in the placebo group, all in combination with DMARD therapy.

Amongst the secondary endpoints, the proportion of patients achieving an ACR50 response at week 24 were 41% in the sarilumab 200 mg group, 37% in the sarilumab 150 mg group and 18% in the placebo group. Additionally the proportion of patients achieving an ACR70 response at week 24 were 16% in the sarilumab 200 mg group, 20% in the sarilumab 150 mg group and 7% for placebo. Treatment-emergent adverse events were more frequent in the sarilumab groups (65 and 66% in sarilumab 200 mg and 150 mg vs 50% in placebo groups, respectively). The results were presented at the American College of Rheumatology (ACR) Annual Meeting.

Comment: Sarilumab is in the same class as Actemra/RoActemra (tocilizumab) from Roche/Genentech and is in competition with another fully human anti-IL-6R antibody, Johnson & Johnson/GlaxoSmithKline's sirukumab, a subcutaneous injection, which is also in Phase III for rheumatoid arthritis and other autoimmune diseases. Sarilumab is likely to be positioned for those who fail to respond adequately to DMARD or anti-TNF agents.