France-based Sanofi and US-based Regeneron Pharmaceuticals have reported positive results with sarilumab in the first Phase III rheumatoid arthritis registration trial.
In the SARIL-RA-MOBILITY Phase III clinical study, sarilumab treatment plus methotrexate (MTX) improved disease signs and symptoms as well as physical function, and inhibited progression of joint damage in adult patients with active rheumatoid arthritis who were inadequate responders to MTX therapy.
The Phase III clinical study enrolled approximately 1,200 patients. The 52-week study evaluated three groups of patients who received, in combination with methotrexate, either a 200mg or 150mg dose of sarilumab, or placebo.
When compared with the placebo group, both sarilumab groups demonstrated clinically relevant and statistically significant improvements in all three co-primary endpoints.
In the SARIL-RA-MOBILITY trial, there was a higher incidence of treatment emergent side effects leading to withdrawal in the sarilumab treatment groups compared with placebo.
The most frequently reported adverse events were infections, as well as increase in LDL cholesterol and transaminases.
Infections were reported with a higher incidence in the sarilumab groups compared with placebo, all in combination with MTX.
A dose dependent decrease in mean neutrophil counts was observed in patients treated with sarilumab.
The safety findings were consistent with those observed in prior investigational studies with sarilumab.
Sanofi sarilumab global project head Tanya M Momtahen noted that irreversible joint damage can be a consequence for patients suffering from rheumatoid arthritis, and this is accompanied by reduced physical function.
"This remains a major concern for rheumatoid arthritis patients. We are encouraged by these Phase 3 results and the impact sarilumab demonstrated on inhibition of progression of structural damage assessed radiographically in this study," Momtahen added.
The SARIL-RA-MOBILITY Phase III clinical trial demonstrated efficacy at both doses of sarilumab, each administered every other week.
Sarilumab, which was developed using Regeneron's VelocImmune antibody technology, is the first fully-human monoclonal antibody directed against the IL-6 receptor (IL-6R).
It is currently under clinical development and its safety and efficacy have not been fully evaluated by any regulatory authority.
Image: X-ray of a hand affected by rheumatoid arthritis. Photo courtesy of Braegel.