The Impact of Growth Factor Utilization on Infection Risk in Patients Receiving Bispecific Monoclonal Antibodies.

BackgroundBispecific monoclonal antibodies (BsAbs) are utilized in patients with relapsed or refractory multiple myeloma (MM) and light chain amyloidosis (AL amyloidosis) but are associated with high rates of neutropenia and infection. Granulocyte colony stimulating factors (G-CSF) offer a potential means to mitigate infection risk and maintain BsAb treatment, however their use alongside BsAbs is not well defined.MethodsThis single-center, retrospective chart review included adult patients with MM or AL amyloidosis who received teclistamab, talquetamab, or elranatamab at Dana-Farber Cancer Institute from 2022 to 2025. The primary outcome was to assess the rate of infections in patients with or without concomitant G-CSF therapy. The secondary outcomes were to compare the infection characteristics and relative dose intensities of BsAbs in patients with or without concomitant G-CSF therapy and to describe the efficacy of G-CSF therapy.ResultsInfection rates were comparable in patients that received G-CSF (60% with G-CSF vs. 41% without; p=0.055). Relative BsAb dose intensity was similar in patients that received G-CSF (95.2% with G-CSF vs. 100% without; p=0.23). G-CSF was effective in resolving grade 3 (89%) and grade 4 (75%) neutropenia, with a median time to resolution of 7 days, and same day administration with BsAb occurred in 69% of patients.ConclusionsG-CSF administration resulted in comparable infection rates and treatment intensity relative to those not receiving G-CSF. G-CSF was effective in resolving neutropenia, often permitting same-day BsAb administration. These findings support the feasibility and utility of G-CSF during BsAb therapy to minimize infection-related complications and treatment deviations.