A Karyopharm Therapeutics multiple myeloma drug candidate faces longer odds for speedy FDA approval after the agency’s staff raised questions about the therapy’s efficacy and safety.

Staff concerns about Karyopharm drug selinexor were detailed in briefing documents posted Friday afternoon, ahead of an advisory committee meeting scheduled for Tuesday. Such panels are convened to assess the risks and benefits of new drugs, and to vote on whether to recommend approval.

Shares of Newton, MA-based Karyopharm (NASDAQ: KPTI) sank more than 43 percent on the news, closing at $5.07 on Friday.

Karyopharm developed selinexor to treat the most serious cases of… Read more »