Karyopharm tanks as sepsis scares plague its cancer contender

Karyopharm ($KPTI) is switching up a Phase II trial on its lead cancer drug after spotting an alarming rate of sepsis in the treatment arm, a move that spooked investors worried the safety issue could affect other ongoing studies.

The Massachusetts biotech is developing selinexor, an oral treatment Karyopharm believes can treat a wide range of solid and hematological tumors. But a spike in dangerous infections have forced the company to alter the dosing in the drug's most advanced trial, a Phase II study in older patients with acute myeloid leukemia.

Looking at interim safety data from the trial, Karyopharm noted 8 cases of sepsis among the 7 patients getting selinexor compared to just two in the pair of patients in the control group. The company observed a similar trend among AML patients in separate Phase I study, evidence enough to scale back the Phase II dose of selinexor by about 35%, Karyopharm said. Moving forward, management believes the new dose can deliver on efficacy while stemming the rate of toxic infection, and the amended protocol will delay final results from the Phase II study until the end of next year.

Investors were less confident in the plan, however, sending Karyopharm's shares down more than 25% Monday morning. The company has lost roughly half of its market value since the start of the year.

Karyopharm pulled off a $109 million IPO in late 2013 on the back of selinexor's potential, and the drug remains on track in registration trials on diffuse large B cell lymphoma and Richter's transformation, a form of leukemia. The company recently kicked off a study pitting selinexor against multiple myeloma, and Karyopharm next plans to launch a late-stage trial of the drug on liposarcoma.

- read the announcement