Raptor Pharmaceutical says that its late-stage study of a new therapy designed to treat people with a rare genetic disease hit its primary endpoint. But even though the biotech company ($RPTP) says the study of the drug met that crucial goal, putting it on a path to a regulatory filing, its stock plunged 28% by the end of the day.
RP103 is designed to give nephropathic cystinosis patients a drug that would only have to be taken every 12 hours, a big step up from Cystagon, the standard therapy which has to be downed four times a day. Investigators for Raptor say that the drug proved non-inferior among the 41 patients recruited for the study, setting up a planned regulatory filing at the FDA.
Researchers reported 7 serious adverse events, but said that only one could be "possibly related" to the experimental drug. That adverse event was resolved along with the others, says Raptor, and all the patients finished the study.
"We are obviously very excited to have successfully met our primary endpoint of this study," said Christopher Starr, CEO of Raptor. Starr may be less happy with the company's stock performance. Shares of the Novato, CA-based developer had dropped to $5.00 by 4:30 EST Monday, down from Friday's close of $6.96.
- here's the Raptor release