A Study Evaluating the Prophylactic Use of Tocilizumab to Prevent Cytokine Release Syndrome With Ramantamig Administration in Participants With Relapsed/Refractory Multiple Myeloma

The purpose of this study is to find out whether giving a single dose of tocilizumab before treatment with ramantamig can help prevent or reduce the severity of cytokine release syndrome (CRS) within 28 days from ramantamig, compared to participants who receive placebo. CRS is an acute inflammatory reaction that can occur during treatment and may be associated with flu-like or other systemic symptoms, such as fever and tiredness.

Inclusion criteria: * Documented diagnosis of multiple myeloma (MM) as defined by the criteria: a. MM diagnosis according to the international myeloma working group (IMWG) diagnostic criteria; b. Measurable disease at screening as assessed by local laboratory as defined in the protocol * Received at least 1 prior lines of antimyeloma therapy * Relapsed or refractory disease as defined: a. Relapsed disease is defined as an initial response to prior treatment, followed by confirmed progressive disease (PD) by the IMWG response criteria greater than (\>) 60 days after cessation of treatment.; b. Refractory disease is defined as failure to achieve a response (that is, partial response or better) or confirmed PD by the IMWG response criteria during previous treatment or less than or equal to (\