This study will evaluate safety, pharmacokinetics (PK), clinical activity and pharmacodynamics (PD) of RO7851624 in participants with RRMM who are triple-class exposed (treated with proteasome inhibitors \[PIs\], immunomodulators \[IMiDs\], and anti-cluster of differentiation 38 \[anti-CD38\] monoclonal antibodies), and have limited remaining standard treatment options due to refractoriness, intolerance, or multiple prior therapies.
Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.
Life expectancy of at least 12 weeks.
Diagnosis of multiple myeloma per International Myeloma Working Group (IMWG) criteria.
Measurable disease.
Treatment with any chemotherapeutic agent, or treatment with any other anti-cancer agent (investigational or otherwise) with insufficient washout prior to first dose of study treatment.
Autologous stem cell transplant (SCT) with insufficient time prior to first dose of study treatment.
Prior allogeneic SCT.
Prior solid organ transplantation.