Karyopharm Therapeutics Inc. announced that it has entered into a clinical trial collaboration and supply agreement with Bristol-Myers Squibb to evaluate the company's proprietary investigational cereblon E3 ligase modulator (CELMoD??) agent mezigdomide in combination with Karyopharm's selinexor, an approved first-in-class inhibitor of Exportin 1 (XPO1), plus dexamethasone in patients with relapsed/refractory multiple myeloma. This trial will evaluate mezigdomide In combination with selinexor doses of either 40mg or 60mg plus dexamethasone In patients who have prior exposure to immunomodulatory (IMiD®?) drug agents, proteasome inhibitors, and anti-CD38 monoclonal antibody treatment. All patients must have received at least two prior lines of therapy, and either have progressed after or are not eligible to receive CAR-T or bispecific antibody treatment.

The primary endpoints of this trial are to assess the objective response rate (ORR) and the clinical benefit rate (CBR). Key secondary endpoints include progression-free survival (PFS), overall survival (OS) and duration of response (DOR). In addition, the trial will evaluate dynamic changes in T-cell populations and activity as patients undergo treatment.

Under the terms of the agreement with Bristol Myers Squibb, Karyopharm will sponsor the trial as a new arm of Karyopharm's Phase 1b/2 STOMP trial and Bristol Myers Squibb will supply the study's clinical drug mezigdomide.