ted duration of response was longer. The response rate in IFN-refractory patients treated with NIPENT was similar to that in NIPENT-treated frontline patients. At a median follow-up duration of 46 months, there was no statistically significant difference in survival between hairy cell leukemia patients initially treated with NIPENT and those initially treated with IFN. However, no definite conclusions regarding survival can be made from these results because they are complicated by the fact that the majority of IFN patients crossed over to NIPENT treatment.
In the Phase 3 SWOG study, 25 patients with hairy cell leukemia died during treatment or follow-up: 18 patients had last received NIPENT (3 of whom had crossed over from IFN), and 7 patients had last received IFN (1 of whom crossed over from NIPENT). Eleven of the 25 deaths occurred within 60 days of the last dose of treatment. Of these, hairy cell leukemia was cited by the investigators as a contributory cause for 1 death in the NIPENT group and 3 deaths in the IFN group. Additionally, infection contributed to the deaths of 3 patients in the NIPENT group and 2 patients in the IFN group. Approximately 4% of hairy cell leukemia patients, in each arm, died more than 60 days after the last dose of either treatment and there was no outstanding cause of death among these patients.
FRONTLINE IFN-REFRACTORYa
eva luable eva luable SWOG 8691b NCI Phase 2
Parameter NIPENT IFN Crossover Studies
N = 138 N=130 N=79 N=44
Response Rates (%)
eva luable CR 84 18 85 58
PR 6 24 4 28
Intent-to-Treat N=170 N=170
CR 68 14
PR 5 18
Median Time to Response (months)
CR 6.6 11.5 6.0 4.2
PR 4.0 6.2 5.8 —
Median Duration of Response (months)
CR NR 8.3 NR >7.7c (CALGB) >15.2c (MDA)
PR NR 15.2 NR —
% Estimated to be in Response After 24 Months
&nb
