A Phase II, Open-Label Study of an Accelerated Infusion Rate of Daratumumab in Patients With Relapsed and Refractory Multiple Myeloma

Introduction/background: Daratumumab is an anti-CD38 monoclonal antibody initially approved as a single agent for the treatment of relapsed and refractory multiple myeloma. The infusion-related reactions (IRRs) commonly seen with intravenous daratumumab have been managed by prolonging the first infusion, temporarily stopping/slowing the rate if reactions occur and using adequate pre- and post-infusion medications. Several retrospective studies have evaluated shorter infusions after ≥ 2 prior doses administered at the standard rates. Although the shorter infusions were well-tolerated, patients in these reports were given heterogeneous daratumumab regimens and had often already received multiple doses at the longer standard rates.

Patients and methods: CMRG-009 is a prospective study designed to demonstrate the safety of accelerated daratumumab infusions commencing with the second dose. After an initial dose on Cycle 1 Day consisting of 8 mg/kg over 4 hours, all subsequent doses were given over 90 minutes.

Results: No grade 3 IRRs were observed with the 90-minutes infusions. Both the safety profile and anti-myeloma effects were otherwise similar to those observed with other single agent daratumumab studies using longer infusion times.

Conclusion: This is the first formal prospective trial using infusion times shorter than the standard schedule directly after an initial 4-hours dose. This rapid infusion protocol has resulted in more efficient resource utilization and has become the standard protocol for the use in all intravenous daratumumab regimens in Canada. This approach has been particularly helpful in shortening chair time during the COVID-19 pandemic and providing a useful alternative in jurisdictions without access to subcutaneous daratumumab.