A Study Comparing QLS32015 Monotherapy Versus Pomalidomide, Dexamethasone (Pd) or Selinexor, Dexamethasone (Sd) in Participants With Relapsed or Refractory Multiple Myeloma

Overall Response (Partial Response [PR] or Better)

Overall response (PR or better) is defined as participants who have a PR or better prior to subsequent antimyeloma therapy in accordance with the IMWG 2016 criteria.

Time frame: Up to 4 years

Very Good Partial Response (VGPR) or Better Response

VGPR or better (Stringent Complete Response \[sCR\]+Complete Response \[CR\]+VGPR) is defined as participants who achieve a VGPR or better response prior to subsequent antimyeloma therapy in accordance with the IMWG 2016 criteria.

Time frame: Up to 4 years

Complete Response (CR) or Better Response

CR or better response is defined as participants who achieve a CR or better response prior to subsequent antimyeloma therapy in accordance with the IMWG 2016 criteria

Time frame: Up to 4 years

Duration of Response (DOR)

DOR is defined as the time interval between the date of initial documentation of a response (PR or better) to the date of first documented evidence of progressive disease according to the IMWG 2016 response criteria or death due to any cause, whichever

Time frame: Up to 4 years

Minimal Residual Disease (MRD) Negativity

MRD negativity is defined as participants who achieve MRD negativity at a threshold of 10\^-5 at any timepoint after the date of randomization and before disease progression or start of subsequent antimyeloma therapy