No Difference in Survival or Long-Term Disease Outcomes in Palifermin-Treated Patients with Hematologic Malignancies Undergoing Hematopoietic Stem Cell Transplantation.

Background: Oral mucositis is an adverse effect of myeloablative therapy which has serious clinical and economic consequences as well as a negative impact upon quality of life. The duration and severity of oral mucositis can be reduced by administering palifermin to patients with hematological malignancies receiving myeloablative therapy and undergoing hematopoietic stem cell transplantation (HSCT). However, we still require additional data on the long-term disease outcomes of patients treated with palifermin. Therefore we present here the long-term, safety data for palifermin-treated HSCT patients followed up for approximately 60 months after the last palifermin dose.

Methods: The long-term safety data were collected during the follow-up phase of 4 parent trials where patients had received at least one dose of palifermin or placebo. Study assessments included overall survival (OS), progression-free survival (PFS), and secondary malignancies. Assessments were made at 6-month intervals during year 1 and annually thereafter until death or loss to follow-up. Kaplan-Meier curves for overall survival and PFS were calculated and the treatment groups were compared using stratified log-rank test.

Results: Altogether 662 patients were randomized to treatment and received either palifermin or placebo (421 palifermin, 241 placebo); 538 patients entered the follow-up study (342 palifermin, 196 placebo). The median follow-up time for patients alive at last visit was 49.8 months (palifermin N=290) and 49.5 months (placebo N=169). There were 131 (32%) and 72 (30%) deaths in the palifermin and placebo groups, respectively. The overall survival curves were similar for both groups (p=0.717). Disease progression occurred in 167 (41%) palifermin- and 87 (36%) placebo-treated patients; the difference in PFS between the two groups was non-significant (p=0.280). Secondary malignancies were observed in 8% of patients in both groups: the incidence of secondary hematologic malignancies was 4% (palifermin: 14/342) versus 5% (placebo: 10/196) while the incidence of solid tumors was 2% in both groups.

Conclusion: The results of this 60-month follow-up study indicate that long-term disease outcomes are not affected by administering palifermin to patients with hematological malignancies who are receiving myeloablative therapy and undergoing HS. There was no difference in OS and PFS between the palifermin and placebo groups. Furthermore there was no difference in the incidence of secondary malignancies between the two patient groups. The incidence of secondary hematologic malignancies and solid tumors was low, comparable between groups, and within the expected range for this patient population.