Sanofi and Regeneron announce positive topline results from Phase 3 studies with sarilumab in patients with rheumatoid arthritis

Sanofi and Regeneron have announced that a Phase 3 study of sarilumab, an investigational, fully-human IL6 receptor antibody, met its co-primary efficacy endpoints of a greater improvement in signs and symptoms of rheumatoid arthritis (RA) at 24 weeks, and physical function at 12 weeks compared to placebo.

The study evaluated the efficacy and safety of two subcutaneous sarilumab doses versus placebo, added to non-biologic disease modifying anti-rheumatic drugs (DMARD) therapy in RA patients who were inadequate responders to or intolerant of TNF-alpha inhibitors (TNF-IR).

Both sarilumab doses showed clinically relevant statistically significant to the placebo

The trial enrolled 546 TNF-IR patients who were randomised to one of three treatment groups self-administered subcutaneously every other week: sarilumab 200 milligrams (mg), sarilumab 150 mg, or placebo, in addition to DMARD therapy. Both sarilumab groups showed clinically relevant and statistically significant improvements compared to the placebo group in both co-primary endpoints:

1. Improvement in signs and symptoms of RA at 24 weeks, as measured by the American College of Rheumatology (ACR20) score of 20%improvement, were as follows: 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.
2. Improvement in physical function, as measured by change from baseline in the Health Assessment Question-Disability Index (HAQ-DI) at week 12. 

The most frequently reported adverse events included infections  and injection site reactions.Serious infections were uncommon. Reduction in neutrophil count was the most common lab abnormality.

Two additional trials from the Phase 3 programmealso met their primary endpoints:

• SARIL-RA-EASY enrolled 217 patients and was designed to evaluate the technical performance and usability of the sarilumab autoinjector device. There were no product technical failures with the auto-injector, the primary endpoint of the study.
• SARIL-RA-ASCERTAIN was a 202-patient safety calibrator study, designed to assess the safety of two subcutaneous doses of sarilumab and tocilizumab infusion in combination with DMARDs in patients with RA who were TNF-IR. There were no clinically meaningful differences between the treatment groups in serious adverse events and serious infections.

Detailed results from all three trials will be presented at future medical congresses.