Photobiomodulation to minimize talquetamab-associated dysgeusia and xerostomia in multiple myeloma: a brief report of four cases

Abstract

BACKGROUND: Talquetamab, a GPRC5D-targeting bispecific antibody, produces high response rates in relapsed/refractory multiple myeloma (RRMM) but is frequently associated with oral adverse effects, most commonly dysgeusia and xerostomia, which can impair nutrition and quality of life. No evidence-based supportive-care intervention has been established for these effects. METHODS: We describe four adults with RRMM who received photobiomodulation (PBM) concomitantly with talquetamab, using a dual-wavelength (660/808 nm) protocol individualized to symptom evolution and patient availability. Dysgeusia and xerostomia were assessed prospectively at each session through structured clinical interview and oral examination, with severity graded for each patient; no formal psychophysical gustatory testing or sialometry was performed. This descriptive, uncontrolled case series was designed to report the feasibility and tolerability of PBM rather than its efficacy. RESULTS: All four patients developed dysgeusia during talquetamab treatment. Two had grade 1, intermittent hypogeusia; two had grade 2 dysgeusia with complete taste loss (ageusia). No patient developed oral mucositis or clinically significant oral pain. All four patients reported xerostomia, with reduced salivary film and whitish, viscous saliva on examination; salivary flow was not measured quantitatively. All patients also received xylitol-based mouthwash and saliva substitutes from the start of talquetamab as concomitant standard supportive care. PBM was well tolerated, with no PBM-related adverse events, and no patient discontinued talquetamab because of oral toxicity. CONCLUSIONS: This series demonstrates the feasibility and tolerability of PBM delivered alongside talquetamab in four patients. Given the small, uncontrolled sample and concurrent supportive interventions, no conclusion can be drawn regarding the efficacy of PBM for talquetamab-associated dysgeusia or xerostomia. Controlled studies with objective, validated outcome measures are needed.