Modification of belantamab mafodotin dosing to balance efficacy and tolerability in the DREAMM-7 and DREAMM-8 trials.

abstractBelantamab mafodotin (belamaf) combined with standard therapies demonstrated significant progression-free survival (PFS) and overall survival benefits in DREAMM-7 and PFS benefit in DREAMM-8 in relapsed/refractory multiple myeloma. Belamaf dose modifications managed adverse events, including belamaf-related ocular events. Ocular events included ocular adverse reactions (eg, dry eyes, photophobia, eye irritation) and protocol-mandated ophthalmic examination findings. Protocol-recommended dose modifications for ocular events were driven by ophthalmic examination findings and included belamaf dose delays until resolution and reductions. We used descriptive analyses to evaluate the impact of dose modifications on managing ocular events and treatment efficacy. In patients with normal baseline vision who were receiving treatment, dose modifications extended belamaf dosing intervals to a median of 8 to 12 weeks by 9 months; the prevalences of reduced vision to bilateral 20/50 or worse and ocular adverse reactions were highest in the first 3 months and remained low at later time points. The median time to resolution after grade ≥2 ophthalmic examination findings was 12 weeks. Rates of belamaf discontinuations due to ocular events were low. Almost all responders (partial response or better) required dose modifications. Most patients achieved a response before an extended (>2 cycles) dose delay; most who had not, subsequently achieved or deepened their response. In DREAMM-7 and DREAMM-8, the median PFS in patients with ≥1 dose delay of ≥12 weeks was 36.6 months and not reached, respectively. Ocular events were common but effectively managed with dose modifications, allowing for patients to remain on treatment and derive robust efficacy benefit. The trials were registered at www.clinicaltrials.gov as #NCT04246047 (DREAMM-7) and #NCT04484623 (DREAMM-8).