Karyopharm flags a PhII overall survival failure for lead drug selinexor in acute myeloid leukemia

Michael G. Kauffman, Karyopharm

Investigators for Karyopharm $KPTI say that it’s clear at the interim analysis stage that its lead drug selinexor has failed a Phase II test for overall survival in acute myeloid leukemia.

The company called it after finding that 13% in the selinexor arm demonstrated a complete response with or without full hematologic recovery, compared to 3% of patients on the physician’s choice control arm. And those complete responders will have a chance to continue treatment with the drug.

The biotech’s shares dropped 16% in after-market trading. But that came after a 25% spike earlier in the day.

What happened?

“After indications of durable responses achieved with selinexor in DLBCL in AACR titles generating upside, this PM KPTI announced d/c of the SOPRA AML study,” noted Jefferies analyst Brian Abrahams. “We had limited expectations for sel in AML given prior data, challenging indication, and high bar for success, and good safety provides comfort for other indications.”

“SOPRA is a robust, well-conducted trial and the response rates achieved with single-agent selinexor in this heavily pretreated older population have been encouraging,” said Hagop Kantarjian, chair of the Department of Leukemia, The University of Texas MD Anderson Cancer Center.  “Importantly, the safety profile was as expected and the recommended Phase 2 dose was generally well-tolerated.  Unfortunately, as is common in AML, the higher response rates observed with single-agent selinexor versus physician’s choice did not translate into extended survival in the overall population of these frail and heavily pretreated patients.”

That leaves the Newton, MA-based biotech focused on multiple myeloma. Last fall Karyopharm reported that it was adding 120 patients to its single-arm multiple myeloma study after touting results for patients who had failed multiple other therapies. Top-line data is slated for next year and the biotech believes it can take the results straight to the FDA.

Karyopharm CEO Michael G. Kauffman had this to say:

While we are disappointed with the overall outcome, we are pleased that 60mg of single-agent selinexor dosed twice per week was well-tolerated and carried no increased risk of sepsis or febrile neutropenia.  At Karyopharm, our primary focus remains the advancement of selinexor in relapsed or refractory multiple myeloma, where we believe we have a clear path to regulatory approval.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
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Atlas Venture Cambridge, MA

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