Characterization of ocular adverse events in patients receiving belantamab mafodotin (belamaf) for >= 12 months: post-hoc analysis of DREAMM-2 study in relapsed/refractory multiple myeloma (RRMM)

Context Belamaf is approved for the treatment of adult patients with RRMM. Ocular symptoms (e.g., dry eye, blurred vision), eye examination findings including keratopathy (superficial punctate keratopathy and/or microcyst-like epithelial changes), and visual acuity changes are common with belamaf. Objective To study the safety profile of belamaf 2.5 mg/kg Q3W in patients treated for ≥12 months in the DREAMM-2 study. Methods Patients with RRMM who had ≥3 prior therapies and were refractory to an immunomodulatory agent and proteasome inhibitor and refractory and/or intolerant to an anti-CD38 monoclonal antibody received single-agent belamaf. Eye examinations were conducted at baseline and prior to each dose. Dose modifications were based on the most severe Keratopathy and Visual Acuity Scale grading. Recovery was defined as grade 1 exam findings/no exam findings and ≤1-line decline in BCVA vs baseline; patient-reported ocular symptoms were graded per the Common Terminology Criteria for Adverse Events v4.03. Results At 13-month follow-up, 14 patients (15%) received ≥12 months of treatment. All experienced ≥1 ocular event (maximum grade: 2 [14%]; 3 [79%]; 4 [7%]) and required ≥2 dose delays, with dose reduction to 1.92 mg/kg in 12 patients (86%). Dose modifications permitted ocular event recovery; belamaf was resumed in all 14 patients. Patients had a mean of 3.6 dose delays (median: 3.5; range: 2–6) with a median duration of 41 days (range: 4–212); 10 patients (71%) had dose delays >63 days. Long delays did not appear to negatively impact clinical response to belamaf: 12 patients (86%) had a clinical response (≥partial response; 11 patients [79%] ≥6 months). All 14 patients had keratopathy. Ocular symptoms occurred in 13 patients (93%); blurred vision, 57%; dry eye, 36%; visual acuity reduced, 21%; and photophobia, 21%. No patients had permanent complete vision loss. Conclusions Dose modification managed ocular symptoms, decreased eye examination findings, and allowed patients the clinical benefit gained from continuing belamaf treatment. Funding GSK (Study 205678, NCT03525678). Drug linker technology licensed from Seagen Inc.; mAb produced using POTELLIGENT Technology licensed from BioWa. Presented at 26th Congress of the European Hematology Association (Lonial et al., 2021); submitted with permission of original authors.