Ocular Adverse Events Associated With Belantamab Mafodotin In Patients With Multitple Myeloma

Ocular adverse events (OAEs) are common with belantamab mafodotin (belamaf) treatment in transplant-ineligible patients (pts) with newly diagnosed multiple myeloma. We present how OAEs evaluation may determine  belamaf dosing so as to prervent ocular toxicity.

Department of Clinical Therapeutics, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece

Health Data Specialists, Dublin, Ireland

Aktina Center, Ophthalmology Center, Athens, Greece

The ongoing phase 1/2 BelaRd study comprises 2 Parts. Part 1 (36 pts) evaluates the safety/tolerability of belamaf 2.5/1.9/1.4 mg/kg and established the recommended phase 2 dose of 1.9 mg/kg q8w/q12w. Best corrected visual acuity (BCVA) and OAEs (as graded with the Keratopathy Visual Acuity scale; Grade 0-4) were measured and described every 4 weeks during the treatment period (median 28.4 months). Belamaf dosing was permitted when OAEs are Grade 0-1. Dry eye disease and vision-related function were assessed with the Ocular Surface Disease Index (OSDI).

Most patients (32/36; 88.9%) were switched to the q12w schedule due to OAEs. Following an infusion at Grade 0 / Grade 1, Grade ≥2 OAEs were observed in 29.7%/48.8% of the subsequent ocular exams, while the median between-dose interval was 10.4/13.0 weeks. Dosing belamaf when Grade <2 or Grade ≥2 dry eye, blurred vision, or visual impairment was observed, resulted in subsequent Grade ≥2 ocular symptoms in 33.5%/80.5% of assessments and a median dosing interval of 12.4/14.7 weeks. Among 875 OSDI exams across cohorts, 40-46% reported ocular symptoms for “all/most/half of the time”, while the respective proportion for daily functioning impairment was only 5-10%.

In order to reduce peak toxicities, manifesting even with the extended dosing interval, belamaf dose reduction should be considered. Severe keratopathy is rare, with a limited role in guiding dosing, as a discordance between BCVA and keratopathy was seldom observed. Although ocular symptoms were often reported, only a minor impairment in eyesight-related functioning was observed.