P13: CAN PATIENT-REPORTED OCULAR SYMPTOMS GUIDE DOSE MODIFICATIONS IN PATIENTS WITH RELAPSED/REFRACTORY MULTIPLE MYELOMA RECEIVING BELANTAMAB MAFODOTIN?

Introduction: Belantamab mafodotin (belamaf) is a B-cell maturation antigen (BCMA)-targeting antibody-drug conjugate approved as a monotherapy for triple-class refractory adult patients with relapsed/refractory multiple myeloma (RRMM). This hypothesis generating post hoc analysis of DREAMM-2 trial (NCT03525678) data examined relationships between corneal exam findings, best-corrected visual acuity (BCVA) changes and direct patient-reported ocular symptoms per the Ocular Surface Disease Index (OSDI) questionnaire. This approach may provide insight into relationships between corneal exam findings, BCVA, ocular symptoms, impact on quality of life to determine if BCVA decline and symptoms can guide dosing. Surrogate marker identification for results from corneal exam findings would help providers determine if dosing adjustments are necessary. Methods: Snellen chart BCVA assessment and corneal eye exams were performed on all patients receiving belamaf (2.5 mg/kg, q3w) by ECPs at baseline (BL) and before each dose. Corneal exam findings (keratopathy) and BCVA were assessed per protocol-defined criteria. Grade (GR) assessment, relative to BL, was based on the worst finding in the worse eye. Patient-reported ocular symptoms and vision-related functioning, as per the OSDI, were used to evaluate the impact of treatment-related ocular toxicity. The OSDI patient-reported outcome questionnaire assesses eye symptoms/effects on vision-related function and was performed in all patients before each belamaf dose. Items 1–5 address the frequency of eye-related symptoms and items 6–9 address functional limitation frequency. OSDI was considered positive, clinically meaningful and potentially treatment associated when at least one question 1–5 (sensitivity to light, gritty/painful eyes, blurred or poor vision) was reported as experienced “all of the time” and at least one question 6–9 (driving at night, reading, working with PC or watching TV) was reported as experienced “most of the time.” Results: GR 3–4 (severe) keratopathy was observed 5% of the time in patients not reporting frequent ocular symptoms measured by the OSDI questionnaire (no items 1–9 ≥ “most of the time”). In patients who reported no items 1–5 “all of the time” AND no items 6–9 ≥ “most of the time” (OSDI negative), GR 3–4 keratopathy was observed 6.5% of the time (Table). In patients who reported “no deterioration from BL” for any OSDI eye-related symptoms or functional limitations, GR 3–4 keratopathy was observed ~3%–7% of the time and GR 0–2 (mild) keratopathy ~23%–34% of the time. Similar results were observed in patients with BL BCVA ≤20/30 who reported “no deterioration from BL” for any eye-related adverse events (AEs) or functional limitations (GR 3–4 keratopathy: ~2%–6% of the time; GR 0–2 keratopathy: ~19%–28% of the time); patients with worse BL visual acuity (BCVA >20/30) who reported “no deterioration” for items 1–9 had lower incidence of GR 3–4 (~0%–1%) and GR 0–2 keratopathy (~3%–8%). Conclusions: These results suggest that hematologists/oncologists may be able to use ocular symptoms and the OSDI tool as potential surrogate markers for eye exam results to help determine whether dosing changes are needed. Validation with other belamaf dose regimens is ongoing. Funding Source: GSK(205678) Encore statement: Previously presented as Poster 2746 at the American Society of Hematology Annual Meeting, 11–14 December 2021; submitted with permission and on behalf of the original authors.