Hydroxyurea and 6-mercaptopurine in the treatment of chronic granulocytic leukemia

Evolving modalities of treatment with interferon alfa-2b for Ph1-positive chronic myelogenous leukaemia

We have administered interferon alfa-2b, alone or in combination with chemotherapy, to 126 Ph1-positive chronic myelogenous leukaemia patients. Of 71 early chronic phase (CP) patients (less than 12 months from diagnosis), 41 (58%) obtained a complete haematological response (CHR). Daily interferon was more effective than intermittent administration. In previously untreated patients, the response was significantly influenced by risk status at diagnosis. Thirty-four out of 71 (48%) patients improved cytogenetically, the median of Ph1+ mitoses declining from 100% to 66% with complete Ph1-suppression in one case. Of 46 late CP patients (greater than 12 months from diagnosis), 32 (70%) achieved CHR with interferon alone or combined with chemotherapy. All 10 patients with disease well controlled by chemotherapy obtained stable CHR with interferon alone. Of 36 partial responders to conventional chemotherapy, 22 (61%) obtained CHR on interferon plus low-dose hydroxyurea. Ph1 mosaicism was reached by 16 (35%) late CP patients (median Ph1+ cells 75%). Of nine accelerated phase patients on interferon plus chemotherapy, one attained CHR, and two responded partially. At a median follow up of 36 months, of 41 CHR patients in early CP, 15 are controlled on interferon, 12 have had autologous bone marrow transplantation (BMT), and two allogeneic BMT. Blastic transformation (BT) has occurred in eight of 41 CHR patients (19%) versus 17 of 30 (57%) non-responders and partial responders to interferon. At a median follow up of 22 months, of 32 late CP patients obtaining CHR, 26 remain on interferon, one had allogeneic BMT, one had autologous BMT, and one developed BT (versus five out of 14 with less than CHR). These studies confirm the haematological and cytogenetic efficacy of interferon in CML and indicate that the disease status at the start of treatment is critical in determining the success of therapy.

Treatment of terminal-phase chronic myelogenous leukemia with intermediate-dose cytarabine and hydroxyurea

We used intermediate doses of Ara-C (IDAra-C) in the treatment of 15 patients with chronic myelogenous leukemia (CML) in blast crisis and, combined with hydroxyurea, in 20 CML patients in accelerated phase. Patients with blastic CML received intensive 5-day courses of IDAra-C 600 mg/m2 every 12 h as a 2-h infusion. Of 15 patients, three achieved complete response (CR) and three partial response (PR), for an overall response rate of 40 per cent. All patients developed severe leukopenia and thrombocytopenia, and two died in hypoplasia. Except nausea and vomiting requiring medication, other nonhematologic toxicities were uncommon. Median response duration was 4 months (range 1 to 7 months). Survival was 5 months for responders and 1.5 months for nonresponders. Patients with CML in accelerated phase were treated with two-day courses of IDAra-C 600 mg/m2 every 12 h by 2-h infusion, every two-three weeks. Daily hydroxyurea 1-1.5 g/day was administered between courses. Of 20 patients, 15 (75 per cent) achieved a good PR with rapid improvement of the symptoms of disease acceleration. The median duration of response was 11 months (range 3 to 38 months); duration was over 24 months in five patients. The median survival from the start of IDAra-C was 13 months for responders and 3.5 months for nonresponders. We conclude that IDAra-C is an effective approach for CML in terminal phase. Its use in 5-day induction courses for blast crisis CML has a response rate comparable to that achieved with high-dose Ara-C. In patients in accelerated phase, the combination of short courses of IDAra-C with hydroxyurea is a well-tolerated treatment able to improve substantially the clinical and hematologic symptoms of disease progression.