Phase 1/2 Study of ISB 1442 in Relapsed/Refractory Multiple Myeloma

The study will be conducted in two phases: * Phase 1: Dose escalation in R/R MM * Phase 2: Dose expansions in select R/R MM Participants will be treated at escalating dose levels in Phase 1 (dose-escalation phase) of the study. Once the safety of ISB 1442 is confirmed and a Recommended Phase 2 Dose (RP2D) is established in Phase 1 for a given indication, Phase 2 will be initiated for that indication. Participants will receive ISB 1442, until disease progression, unacceptable toxicity, or any criterion for stopping the study drug or withdrawal from the trial occurs.