Potential Cause Identified for Rare Side Effect in Syfovre Injection

Apellis Pharmaceuticals Inc. (APLS, -2.26%) experienced a significant boost in premarket trading on Wednesday, with shares jumping 30%. This surge followed the company’s announcement of the discovery of a potential cause for a rare but serious side effect related to its Syfovre injection, designed to treat age-related macular degeneration.

According to a release issued by Apellis on Tuesday, structural variations were detected in a specific filter needle that is used to extract the treatment from the vial during the preparation of the injection. The company clarified that while a direct link between these needles and the reported cases of retinal vasculitis (inflammation of the retinal vessels) has not been established, it is recommending healthcare professionals to employ an alternative needle already in circulation.

To date, there have been eight confirmed cases of retinal vasculitis associated with the use of Syfovre. Apellis noted that two of these patients are currently suffering from severe vision impairment, which is unlikely to be resolved.

Despite the recent setback, Apellis shares have experienced a 40.5% decline since the beginning of the year. In comparison, the S&P 500 (SPX, -0.28%) has achieved a gain of 14.3%.