Interferon in the treatment of hairy cell leukemia

Abstract

An ongoing multicenter study has confirmed earlier observations that interferon alfa-2b (Intron A, Schering Corp., Kenilworth, NJ) is effective in the treatment of hairy cell leukemia (HCL). The 212 evaluable subjects in this trial received 2 X 10(6) U/m2 of interferon alfa-2b subcutaneously, on an outpatient basis, three times a week for 1 year. Of this group, 166 had previously undergone splenectomy, and 94 had received chemotherapy; 96% had more than 50% hairy cells in the bone marrow. Objective responses (complete, partial, and minor) were recorded in 89% of the study group and were characterized by a marked reduction in infections as well as in the need for transfusions. Complete response, defined as a normal complete blood count (CBC) and less than 5% hairy cells in the marrow, was achieved in 4% of the subjects. Partial responses (normal CBC) were attained in 74%, and minor responses (normalization of subnormal hematocrits or granulocyte or platelet counts) in 11%. Normalization of CBC usually did not occur until after 2 to 5 months of therapy. Results were comparable in splenectomized and nonsplenectomized patients. After 1 year of treatment, the responders were randomized to continue therapy for 6 months or to stop treatment and remain under observation. Preliminary findings have shown no significant differences in the incidence or time to progression of disease in the two groups, but additional data will be required before conclusions can be reached with regard to the need for maintenance therapy. Overall, the results of this study indicate that interferon alfa-2b is well tolerated, produces durable responses, and dramatically improves the quality of life in a high percentage of patients with progressive HCL.

The biology of hairy cell leukemia

“…In 1984 Quesada et a1 first reported that monotherapy with partially purified natural leucocyte IFN-a was able to induce remissions in HCL (11). This report was subsequently corroborated in larger studies establishing IFN as the gold standard for HCL treatment (12,(160)(161)(162)(163)(164)(165)(166)(167)(168)(169)(170)(171). The different IFN species were used in doses of 10 -20 x lo6 IU/week divided into 3 or 7 doses administered either by s.c or i.m.…”

“…injections often on an outpatient basis. The IFN employed was recombinant IFN-a (12,(160)(161)(162)(163)(164)(167)(168)(169)(170), recombinant IFN-P (171) and lymphoblastoid IFN (165,166), whereas IFN-y had noor only questionable effect (172) ( Table 3). Also patients with T-HCL seemed to respond (173), whereas some rare HCL variants have showed a poor response (82,83).…”

“…exposure to foreign antigens, altered cells, lymphocyte mitogens, virus particles, and intracellular bacterias. Clinical trials in HCL have been performed with both naturally occurring mixtures of IFN (11, 165,166) and highly purified single recombinant IFN species (12,(160)(161)(162)(163)(164)(167)(168)(169)(170)(171), and no major differences have been found between the effects and side-effects of the different type I IFN.…”

The Complete Spleen

“…For many years, splenectomy and a interferon Spiegel, 1987;Thompson and Fefer, 1987;Fahey et aI., 1987) were the standard treatment approaches to HCL. The majority of patients on a interferon are known to relapse after stopping therapy (Jaiyesimi et aI.…”

Human lymphoblastoid interferon as initial therapy in hairy cell leukaemia: a multicentre study in non‐splenectomized patients

“…After that. an increasing number of patients were treated with alpha-IFN, either recombinant or lymphoblastoid (Flandrin et al, 1987: Quesada et al 1986: Worman et al 1987: Thompson & Fefer. 1987: Pralle et al 1987: Damasio et al 1987Glaspy et al 1987).…”