Long-Term Safety Outcomes in Patients with Hematological Malignancies Undergoing Autologous Hematopoietic Stem Cell Transplantation Treated with Palifermin to Prevent Oral Mucositis

The purpose of our study was to compare long-term safety outcomes (overall survival, disease progression, and incidence of secondary malignancies) between palifermin and placebo in the prevention of oral mucositis in patients with hematological malignancies undergoing autologous hematopoietic stem cell transplantation (HSCT). Patients were enrolled between 1997 and 2005 into 4 phase I to III studies (3 double-blind placebo-controlled and 1 open-label) conducted at 31 sites in Australia, Europe, and the United States. Survival outcomes (overall survival, progression-free survival) were compared using hazard ratios (HRs) estimated with a Cox model that included treatment group, baseline age, disease type, Eastern Cooperative Oncology Group performance status, country, and presence of prior radiotherapy as covariates. The incidence of secondary malignancies was compared with a chi-square test. A total of 672 patients were randomized into the studies (428 palifermin and 244 placebo). The median follow-up time for subjects alive at last visit was 7.9 years (range, .1 to 14.9) for palifermin and 8.8 years (range, .1 to 14.8) for placebo. Palifermin-treated patients had overall survival (HR, 1.01; 95% confidence interval [CI], .78 to 1.31; P = .921) and progression-free survival times (HR, 1.04; 95% CI, .83 to 1.31; P = .733) that were comparable with placebo-treated patients. Secondary malignancies were reported by 13% of palifermin-treated patients versus 11% of placebo patients (P = .477). Breakdown into secondary hematological malignancies (7% versus 6%) or solid tumors (6% versus 6%) did not suggest any differences between the treatment groups. After a follow-up of up to 15 years, comparable long-term safety outcomes (overall survival, progression-free survival, and incidence of secondary malignancies) were observed for palifermin- and placebo-treated patients undergoing autologous HSCT.