Selinexor and Backbone Treatments of Multiple Myeloma Patients (STOMP)

This study will independently assess the efficacy and safety of 11 combination therapies in 12 arms, in dose-escalation/-evaluation and expansion phases, for the treatment of patients with relapsed/refractory multiple myeloma (RRMM) and newly diagnosed multiple myeloma (NDMM). The combinations to be evaluated are: Arm 1: Selinexor + dexamethasone + pomalidomide (SPd) Arm 2: Selinexor + dexamethasone + bortezomib (SVd); enrollment complete Arm 3: Selinexor + dexamethasone + lenalidomide (SRd) in RRMM; enrollment complete Arm 4: Selinexor + dexamethasone + pomalidomide + bortezomib (SPVd) Arm 5: Selinexor + dexamethasone + daratumumab (SDd); enrollment complete Arm 6: Selinexor + dexamethasone + carfilzomib (SKd) Arm 7: Selinexor + dexamethasone + lenalidomide (SRd) in NDMM Arm 8: Selinexor + dexamethasone + ixazomib (SNd) Arm 9: Selinexor + dexamethasone + pomalidomide + elotuzumab (SPEd) Arm 10: Selinexor + dexamethasone + belantamab mafodotin (SBd) Arm 11: Selinexor + dexamethasone + pomalidomide + daratumumab (SDPd) Arm 12: Selinexor + dexamethasone + mezigdomide (SMd) Selinexor pharmacokinetics: PK Run-in (Days 1-14): Starting in protocol version 8.0, patients enrolled to any arm in the Dose Escalation Phase (i.e., Arm 4 [SPVd], Arm 6 [SKd], Arm 8 [SNd], Arm 9 [SPEd], Arm 10 [SBd], and Arm 11 [SDPd]) will also first be enrolled to a pharmacokinetics (PK) Run-in period until 9 patients have been enrolled to this period to evaluate the PK of selinexor before and after co-administration with a strong CYP3A4 inhibitor. This run-in period does not apply to Arm 12 (SMd).