FDA delays selinexor NDA decision, but Karyopharm rockets

US drugmaker Karyopharm Therapeutics (Nasdaq: KPTI) saw its shares soar nearly 30% in pre-market trading on Friday, despite revealing that the US Food and Drug Administration has extended the Prescription Drug User Fee Act (PDUFA) action date for the New Drug Application (NDA) for selinexor.

The NDA, which is currently under Priority Review by the FDA, is seeking accelerated approval for selinexor in combination with dexamethasone for the treatment of patients with relapsed refractory multiple myeloma who have received at least three prior therapies and whose disease is refractory to at least one proteasome inhibitor (PI), one immunomodulatory agent (IMiD), and one anti-CD38 monoclonal antibody. The previously disclosed April 6, 2019 PDUFA date has been extended by three months to July 6, 2019.

On February 26, 2019, the FDA's Oncologic Drugs Advisory Committee (ODAC) met to discuss the selinexor NDA and voted 8 to 5 recommending that the FDA wait for the results from Karyopharm's randomized, open-label, Phase III BOSTON study evaluating selinexor in patients with relapsed or refractory multiple myeloma, before making a final decision regarding approval.