Top-line data from a Phase III trial of Regeneron/Sanofi’s fully human monoclonal antibody sarilumab show that the drug significantly improved signs and symptoms of rheumatoid arthritis compared to placebo.

The drugmakers said both doses assessed in the SARIL-RA-TARGET study showed “clinically relevant and statistically significant improvements” versus the placebo arm on the co-primary endpoints of improving symptoms of the disease and physical function.

Improvement in signs and symptoms of RA at 24 weeks, as measured by the American College of Rheumatology score of 20 percent improvement (ACR20), were: 61% in the sarilumab 200mg group; 56% in the sarilumab 150mg group; and 34% in the placebo group, all in combination with DMARD therapy.

On the safety side no warning signals were raised, the most frequently reported side effects including infections (30%, 22% and 27% in the 200mg, 150mg and placebo groups, respectively) and injection site reactions (8%, 7%, 1% in the 200mg, 150mg and placebo groups, respectively). Serious infections were uncommon, the firms said.

A US regulatory submission is planned for the fourth quarter of this year.