LONG-TERM RESULTS WITH 2'DEOXYCOFORMYCIN IN HAIRY-CELL LEUKEMIA

We have treated 159 patients with hairy cell leukemia (HCL) with 2'deo xycoformycin (DCF) in a phase II study that started in 1986. 151 patie nts had typical HCL and 8 HCL-variant. Ages ranged from 30 to 81 years . Most patients had previously received interferon-alpha, splenectomy or both and 23 had DCF as first line; all had active disease. In the f irst 40 patients DCF was given at 4mg/m(2) weekly for 4 weeks and ever y 2 weeks thereafter and in the remainder every 2 weeks until maximal response. Three patients died early on and were non-evaluable for resp onse. The response rates in 148 patients with typical HCL were: CR 74. 3%, PR 22.3% and NR 3.4%. None of the HCL-variants achieved CR; 4 had PR and 4 NR. The median number of DCF injections to CR was 9. Lymphope nia and neutropenia were seen in 52% and 34%, respectively, but 72% of patients started treatment with low leucocyte counts. 27% had infecti ous complications of which 6% were life threatening. The disease free interval of the first 105 remitters (CR + PR) was 84% at 4 years with no significant difference between CR (86%) and PR (77%). There have be en 12 relapses at a median time of 22 months (range 6-60 months) since stopping DCF; of these, 5 had massive abdominal lymphadenopathy, a fe ature seen also in 4 of the 5 primary non-responders. There were 13 de aths but 7 were unrelated to HCL. The 5-year survival from starting DC F in 110 patients with typical HCL was 88% and 97% if we exclude non-H CL deaths. We conclude that DCF has improved significantly the remissi on rate, disease free interval and survival in HCL. Longer follow-up w ill determine whether some of the patients can be considered cured.