P-202: Characterization of ocular adverse events in patients receiving Belantamab Mafadotin for ≥12 months: post-hoc analysis of DREAMM-2 study in relapsed/refractory Multiple Myeloma

Abstract

<h3>Background</h3> The B-cell maturation antigen–targeting antibody–drug conjugate belantamab mafodotin (belamaf; GSK2857916) is approved for the treatment of adult patients with heavily pretreated relapsed or refractory multiple myeloma (RRMM). Ocular symptoms (eg, 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. This post-hoc analysis characterizes the safety profile of belamaf 2.5 mg/kg Q3W in patients treated for ≥12 months in the DREAMM-2 study. <h3>Methods</h3> Patients with RRMM who had ≥3 prior therapies, including an immunomodulatory agent and proteasome inhibitor, 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, which considers corneal exam findings and best corrected visual acuity (BCVA) changes from baseline. Recovery was defined as Grade 1 exam finding/no exam finding, and ≤1-line decline in BCVA vs baseline. Patient-reported ocular symptoms were graded per Common Terminology Criteria for Adverse Events version 4.03. <h3>Results</h3> At 13-month follow-up, the clinical benefit rate (≥minimal response) in patients receiving belamaf 2.5 mg/kg (n=97) was 36%; 14 patients (15%) had received ≥12 months of treatment. All 14 patients 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, so belamaf was resumed in all 14 patients. Patients had a mean of 3.6 dose delays (median: 3.5; range: 2–6). Median duration of dose delays was 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 (86%) had a clinical response (≥partial response; 11 [79%] for ≥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. <h3>Conclusions</h3> In this subset of patients receiving belamaf treatment for ≥12 months, dose modification was effective in managing ocular symptoms and decreasing findings at eye examination, and allowed patients the clinical benefit gained from continuing treatment with belamaf. The safety profile of belamaf will be further characterized in ongoing analyses and studies. <h3>Funding</h3> GlaxoSmithKline (Study 205678, NCT03525678). Drug linker technology licensed from Seagen Inc.; mAb produced using POTELLIGENT Technology licensed from BioWa. © 2021 European Hematology Association, Inc. Reused with permission. This abstract was accepted and previously presented at the 2021 EHA Annual Meeting. All rights reserved.