Differential Effect of Supersaturated Calcium Phosphate Rinse and Palifermin on Oral Mucositis Induced By Conditioning with Fludarabine, Busulfan and TBI or Melphalan

Introduction: Oral mucositis (OM) is a common, debilitating complication of conditioning regimens for hematopoietic stem cell transplantation (HSCT). Supersaturated calcium phosphate rinse (SCPR) and palifermin have shown efficacy in preventing OM. However, whether their efficacy differs is unknown. We compared the efficacy of SCPR and palifermin in HSCT patients receiving myeloablative conditioning. Methods: A comprehensive review of our institutional database was performed to identify patients who received myeloablative-conditioning between 2008 and 2012. Two cohorts were identified and analyzed separately. All patients in the first cohort received 400 cGy of total body irradiation and the majority received Fludarabine 250 mg/m2 and Busulfan 12.8 mg/m2 (FBT). All patients in the second cohort received melphalan 200 mg/m2. The incidence and grade of OM were assessed in both groups using the WHO grading system. Results: A total of 247 consecutive patients were identified. In the FBT cohort, 26 patients received SCPR and 122 patients received palifermin for OM prophylaxis. In the Melphalan cohort, 68 patients received SCPR and 31 patients received palifermin for OM prophylaxis. In the FBT cohort, the incidence of grade 3 or 4 OM was significantly lower in the palifermin compared to SCPR group (57% vs 100%, OR=0.19, p<0.0001). The overall incidence of OM was lower in the palifermin compared to SCPR group (86% vs 100%, OR=0.42, p=0.06). In the melphalan cohort, the incidence of grade 3 or 4 OM was significantly lower in the SCPR compared to the palifermin group (12% vs 35%, OR=0.24, p=0.008). The overall incidence of OM was lower in the SCPR compared to the palifermin group (28% vs 58%, OR=0.28, p=0.005). Conclusion: While palifermin is more effective than SCPR in preventing FBT-induced OM, SCPR appears more effective in preventing melphalan-induced OM. These findings challenge the current accepted biological model that views OM as a universal outcome regardless of the causative agent. We propose individualized selection of OM prophylactic agent based on the type of conditioning therapy.