FDA delays approval of Sanofi and Regeneron's RA candidate sarilumab

The US Food and Drug Administration issued a Complete Response Letter (CRL) regarding the Biologics License Applications (BLA) for sarilumab, an investigational interleukin-6 receptor (IL-6R) antibody for the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA).

Friday was the day that the FDA was scheduled to announce its decision on the approval or otherwise of the drug, which is being developed by French pharma major Sanofi (Euronext: SAN) and US partner Regeneron Pharmaceuticals (Nasdaq: REGN). The companies have previously predicted that the drug could be a blockbuster with sales in excess of $1 billion a year. The Evaluate group has forecast that 2020 sales will hit $1.8 billion.

Sanofi’s shares closed up 3.7% at 71.43 euros on Friday, though this was more likely a result of a positive reaction to the firm’s third-quarter financial results that were reported the same day. Regeneron’s shares slipped 2.6% to $355.83 by close, but recovered slightly to $360.00 after-hours.