Talquetamab-Induced Dysgeusia Successfully Treated With Photobiomodulation Therapy

Multiple myeloma is a malignancy characterized by clonal proliferation of plasma cells in the bone marrow. The treatment of patients with relapsed or refractory multiple myeloma remains a challenge. Talquetamab is a recently approved drug, a first-in-class GPRC5D-targeting T-cell redirecting bispecific antibody, for treatment of patients with triple-class exposed relapsed/refractory multiple myeloma. Patients who underwent drug therapy have experienced oral side effects such as xerostomia and dysgeusia. This report describes the case of a 61-year old man with triple-class exposed refractory multiple myeloma who developed talquetamab-related dysgeusia that was successfully treated with photobiomodulation (PBM). The patient began to complain of loss of taste three days after the administration of talquetamab. PBM was performed every 48 h with 25 J/cm² per treatment field using the Therapy EC device (DMC; model number: #75153; red: 660 nm ±10 nm; infrared: 808 nm ±10 nm; fixed power of 100 mW ±20%; beam area of 0.04 cm², and irradiance of 2.5 W/cm²) during the talquetamab escalation phase. The application of laser was performed in 78 points distributed throughout the oral cavity. After 7 days/third session of PBM, the patient displayed a significant improvement in sensitivity to tastes, mainly salty and bitter. After 7 weeks of follow-up, there was a slight reduction in sensibility to salty and no change in other tastes. The current clinical report demonstrated the potential effectiveness of a PBM protocol developed for the treatment of talquetamab-related dysgeusia. The management of this oral side effect using PBM could prevent treatment interruption and improve the patients' quality of life.