Treatment
toxicity
DISEASE PROGRESSION
All patients received subcutaneous elranatamab 76 mg QW on a 28-d cycle with a two step-up priming dose regimen of 12 mg on day 1 and 32 mg on day 4 during the first week, with the exception of the first four patients enrolled in the study who received a single priming dose of 44 mg on day 1 before receiving the full dose of 76 mg starting on day 8. These first four patients were enrolled before the protocol was amended to include the 12/32 mg step-up regimen. Hospitalization was required for 48 h following the first step-up dose and for 24 h after the second step-up dose. Premedication with acetaminophen (650 mg or equivalent), diphenhydramine (25 mg or equivalent) and dexamethasone (20 mg or equivalent) was required before each step-up dose and before the first full dose of elranatamab. Patients who received QW dosing for at least six cycles and achieved a PR or better (≥PR) persisting for at least 2 months had their dosing interval changed to Q2W. Dose reductions and interruptions were permitted for toxicity. Elranatamab treatment was to be continued until disease progression, unacceptable toxicity or withdrawal of consent.