Approval decision delay seen as positive for Karyopharm
- The Food and Drug Administration pushed back the deadline for an approval decision by three months for Karyopharm Therapeutics' experimental cancer drug — and investors celebrated the delay.
- The drugmaker gave the agency additional clinical information on selinexor's accelerated approval application as a late-line treatment for relapsed refractory multiple myeloma, leading the FDA to revise its scheduled decision date from April 6 to July 7, the company said Thursday.
- While such a delay might typically be viewed negatively, multiple Wall Street analysts welcomed the later deadline. They reasoned the FDA information request, which followed a negative advisory committee vote last month on the drug, suggests regulators "remain open to the possibility" of granting an OK, RBC Capital Markets' Brian Abrahams wrote. Karyopharm's stock opened 15% higher Friday morning.
The company provided few specifics on the development, leaving several sell-side analysts to speculate on exactly what additional data Karyopharm gave reviewers. That could be important, as the FDA advisory panel voted 8-5 last month to recommend the FDA wait for results from an ongoing Phase 3 study called BOSTON, before reaching a final decision.
Top-line data from that late-stage study is expected in late 2019 or 2020, pending progression-free survival events, the company noted last month. Its primary completion date is listed for June 2020, according to a federal clinical trials database.
Analysts from Jefferies and SVB Leerink both suspect the company has now given interim data from that late-stage study to the agency, noting company leaders have previously said interim data from BOSTON exists.
But Karyopharm didn't specifically confirm that Friday in response to questions from BioPharma Dive, saying the additional data was from ongoing studies.
"The FDA requested existing clinical data from ongoing selinexor studies which Karyopharm submitted earlier this week as an amendment to the selinexor NDA," the company stated to BioPharma Dive.
The company also noted in its March 14 statement that the advisory committee vote provides non-binding recommendations, and approval remains the FDA's call. Still, the agency usually follows the advice of its panels.
Karyopharm is seeking an accelerated approval for selinexor in combination with dexamethasone for heavily pretreated multiple myeloma patients who have gone through at least three prior therapies. Selinexor is a selective inhibitor of nuclear export that specifically blocks XPO1.
The BOSTON study is testing selinexor along with dexamethasone and Velcade (bortezomib) in a wider range of multiple myeloma patients.
According to Wall Street analysts, a delayed approval decision could actually be good news for Karyopharm.
"It indicates the negative views at the AdCom did not translate to a 'done deal' as most concluded," Jefferies analyst Maury Raycroft wrote to investors in a March 15 note.
Briefing documents prepared by FDA staff for the advisory panel meeting, however, raised several concerns with the drug that could remain hurdles to approval. In particular, FDA reviewers questioned whether the efficacy shown was sufficient to outweigh the risks of treatment, and noted the lack of a control arm made it difficult to isolate selinexor's treatment effect from dexamethasone.
Shares in the Newton, Massachusetts-based company climbed to trade at roughly $5 apiece Friday. However, that's still about one-third of its trading value from a year ago.
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