Oral Care™ kit as a prophylaxis for talquetamab-associated toxicities in patients with Relapsed/Refractory multiple myeloma

Abstract

Abstract Background: Talquetamab, a GPRC5D×CD3 bispecific antibody, has shown promising efficacy in relapsed/refractory multiple myeloma (RRMM) but is associated with a high incidence of mucocutaneous toxicities, particularly oral events such as dysgeusia, xerostomia, and dysphagia. These adverse effects can significantly impair nutritional intake, treatment adherence, and overall quality of life. Current management is largely reactive and supportive, with no standardized prophylactic interventions. While emerging strategies such as topical corticosteroids, nutritional agents, and photobiomodulation are under investigation, real-world data on preventive care remain limited. We evaluated the potential benefit of an Oral Care™ Kit made available by (un)cancer LLC —comprising toothpaste containing 10% nanohydroxyapatite with xylitol, mouthwash and lozenges containing xylitol, chapstick, and enamel-protective agents—as a prophylactic measure to reduce talquetamab-associated toxicities. Methods: In this retrospective study, we analyzed 16 RRMM patients treated with talquetamab at Moffitt Cancer Center between February 2025 and June 2025. Eight patients received the Oral Care™ Kit starting on cycle 1 day 1, while the remaining eight did not and were selected as control as they received therapy during the same time span. Treatment assignment was non-randomized, and patient selection for each group was voluntary. The comparator group was treated during the same time period to minimize temporal bias. Patients in the intervention group were instructed to use the kit's contents daily. Toxicity data (oral, skin, and nail), as well as weight metrics (baseline, post-ramp-up, after first full dose at 30), were collected. Bridging therapy status, baseline height, and weight were also recorded. Weight change was used as a proxy for nutritional impact. Continuous variables were summarized using both mean and median values, while categorical variables were reported as frequencies and percentages. Statistical comparisons were performed using the Kruskal–Wallis test for continuous variables and Fisher's exact test for categorical variables. Results: Baseline characteristics were comparable between the two groups, including age, gender, race, ethnicity, performance status, prior CAR-T therapy, prior autologous stem cell transplant (ASCT), presence of high-risk cytogenetics, number of prior lines of therapy, and baseline albumin levels. Of the eight patients who received the Oral Care™ Kit, seven reported using it. Among those, four found the toothpaste helpful, while one patient each reported benefit from the lozenges and mouthwash. Oral toxicities were common in both groups: 7 of 8 patients (88%) in the kit group and 6 of 8 patients (75%) in the non-kit group experienced at least one oral adverse event. In the kit group, toxicities were primarily dysgeusia (6/7), with three cases also reporting dry mouth, one of which included dysphagia and another stomatitis. One patient in the kit group experienced dysphagia and oral erythema. In contrast, all six patients with oral toxicities in the non-kit group experienced dysgeusia, with additional symptoms including dry mouth (n=1), dry mouth and anorexia (n=1), and anorexia (n=1) and dysphagia (n=1). Median baseline height (171.0 cm vs. 164.8 cm, p=0.207) and weight (83.1 kg vs. 70.0 kg, p=0.294) were not significantly different between non-kit and kit groups, respectively. Weight loss after ramp-up was comparable between groups (median: -3.5% non-kit vs. -3.4% kit, p=0.600). However, after one full treatment cycle, patients in the kit group experienced greater weight loss (median: -6.9% vs. -1.2%; mean: -6.8% vs. -0.9%, p=0.083). Conclusion: Oral toxicities were common in both the kit and non-kit groups, with dysgeusia being the most frequently reported symptom. While the overall profile of oral events differed slightly between groups, no clear pattern of benefit associated with the Oral Care™ Kit was observed. Weight loss after one full treatment cycle appeared greater in the kit group, although the difference did not reach statistical significance. Given the small sample size and non-randomized design, these findings should be interpreted with caution. Further prospective studies are needed to identify effective strategies for managing talquetamab-associated toxicities.