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18 patients with early stage, previously untreated B-CLL were given interferon alfa (IFN alpha) 2a. 3 MU thrice weekly, subcutaneously. The peripheral lymphocyte count decreased in all patients. Response was delayed in three patients until they had received a median of 5 months therapy, one of whom had an initial transient increase in lymphocytes. Two patients normalized their blood lymphocyte counts, but neither achieved complete remission (CR). Responses were transient in eight patients lasting a median of 5 months (3-21). Binding anti-IFN alpha antibodies were present in 9/17 patients tested (53%). Low titre binding antibodies (< 533 IBU/ml) were not associated with LHR, but high titre antibodies (> 4401 IBU/ml) were. Two of 12 patients assessed had a > 3 g/l increase in baseline serum IgG levels during IFN alpha therapy, one of whom reverted to pretreatment levels in association with LHR. Haematological toxicity was moderate, other than in two patients, one of whom developed autoimmune haemolytic anaemia and the other thrombocytopenia. We conclude that IFN alpha lowers the lymphocyte count in early stage CLL, that the response may be delayed and that anti-IFN alpha antibodies may play a role in a proportion of those in whom the response is transient.

Eleven patients with acute myeloid leukaemia (AML) in first complete remission (CR) were treated with alfa-2a-interferon (for short ‘interferon’) maintenance therapy, at a dose of 3 MU twice to thrice weekly subcutaneously. Adjustments were made to maintain neutrophil counts > 1 × 10⁹/1 and platelet counts > 100 × 10⁹/1· A transient fall in haemoglobin, neutrophil and platelet counts was noted in all 9 evaluable patients. Median time to nadir was 7 weeks. Initial dosage reductions were necessary in 5 patients, 3 of whom were later able to tolerate the starting dose. No episodes of infection or bleeding were documented during therapy and no red cell or platelet transfusions were necessary. At the time of writing (median follow-up of 31 weeks), 7 patients continue in CR, 6 of whom remain on interferon. One patient discontinued interferon on developing sicca syndrome. Other than in this patient, side effects were minor. Mean dose administered was 6.7 MU/patient/week. We conclude that low-dose IFN maintenance therapy is well tolerated in older patients with AML in first CR.

Eighteen patients with early stage, previously untreated B-cell chronic lymphocytic leukemia (B-CLL) were given recombinant interferon-a2a (IFN-a2a) 3 MU thrice weekly, subcutaneously. The peripheral lymphocyte count decreased in all patients, but responses were transient in 8, lasting a median of 5 months (range, 3-21). Binding anti-IFN-a antibodies were present in 9/17 patients tested (53%). These were first detected at a median of 7 months (range 2-17). Low-titer antibodies [titers <530 IFN binding units (IBUVml)] were not associated with loss of hematological response (LHR), but high-titer antibodies (>4,400 IBU/ml) were. Of the 8 patients who lost response, 3 were antibody positive, 3 were negative, and 2 were of unknown antibody status at the time of LHR. We conclude that IFN-a2a lowers the lymphocyte count in early-stage CLL, that the response may be delayed, and that anti-IFN-a antibodies may play a role in some of those in whom the response is transient.*1' CLL is characterized by the progressive accumulation of lymphocytes, usually of B-cell origin. Reports of earlier trials of IFN-a in CLL<2> indicated that it had only limited activity, but these focused mainly on previously treated patients, many with advanced disease. The present study investigated the role of recombinant IFN-a2a (Roferon, Roche) in previously untreated patients with early stage B-cell CLL.The 10 males and 8 females in our study had a median age at entry of 60, and all were in Binet stage A. The median peripheral absolute lymphocyte count was 25 x 109 before treatment (range 10-95). IFN-a2a was injected subcutaneously, at a dose of 3 Mu, thrice weekly.

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