Karyopharm Initiates STOMP Clinical Trial of Oral Selinexor in Multiple Myeloma

Karyopharm Therapeutics Inc.

, a clinical-stage pharmaceutical company, announced today the initiation of the Selinexor and Backbone Treatments of Multiple Myeloma Patients, (STOMP) study. STOMP is a multi-center, Phase 1b/2 study of selinexor and other standard therapies in patients with multiple myeloma (MM). Selinexor, the company's lead, novel, oral Selective Inhibitor of Nuclear Export/SINE™ compound, will be evaluated in combination with low-dose dexamethasone in independent cohorts with bortezomib (Velcade®), lenalidomide (Revlimid®) and pomalidomide (Pomalyst®). Selinexor and low dose dexamethasone is already being combined with carfilzomib (Kyprolis®) in an Investigator Sponsored MM Trial, where promising preliminary data were presented at the American Society of Hematology (ASH) 2014 Annual Meeting. Selinexor has received orphan drug designation from both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for MM. "The activity demonstrated to-date in multiple myeloma with selinexor and low-dose dexamethasone, as well as the combination of selinexor and low-dose dexamethasone with carfilzomib, is encouraging and we look forward to further evaluating the activity of selinexor-based combinations in patients with multiple myeloma whose disease has relapsed following, or is refractory to, various agents," said Sharon Shacham, PhD, MBA, President and Chief Scientific Officer of Karyopharm. "Despite the availability of new therapies for multiple myeloma, nearly all patients eventually relapse and eventually succumb to this disease. We hope the selinexor/low-dose dexamethasone regimen in combination with existing therapies will improve the outcomes for these patients." This multi-arm Phase 1b/2 study will evaluate the safety and efficacy of selinexor and low-dose dexamethasone at 60mg and 20mg, respectively, twice weekly or 80mg and 40mg, respectively, once weekly in separate combinations with either bortezomib, lenalidomide or pomalidomide. 220 patients with MM whose disease has relapsed after one or more prior therapies are expected to enroll in STOMP and overall response rate (ORR) is the primary endpoint of the study. STOMP was designed based on both preclinical combination data as well as from Karyopharm's ongoing Phase 1/2 study of selinexor with low-dose dexamethasone in combination with the proteasome inhibitor carfilzomib in relapsed/refractory multiple myeloma. Phase 1/2 data demonstrating the activity of selinexor with low-dose dexamethasone in combination with carfilzomib were presented at ASH 2014. In this ongoing study conducted by investigators at the University of Chicago, the first three patients, all of whom had MM refractory to carfilzomib and dexamethasone, were treated with selinexor, dexamethasone and carfilzomib achieved at least partial responses. Further clinical updates from this ongoing study are expected at the ASH 2015 annual meeting.