Cytosine arabinoside and 6-thioguanine in the treatment of childhood acute myeloblastic leukemia

Pregnancy during therapy for childhood acute lymphoblastic leukemia: two case reports and a review of the literature

PURPOSE

The incidence and consequences of pregnancy during therapy for childhood acute lymphoblastic leukemia (ALL) are largely unknown. To explore the issues involved in this complication of ALL treatment, two recent cases are presented.

PATIENTS

Two 15-year-old girls with "high risk" ALL became pregnant while receiving maintenance therapy.

RESULTS

In one case, the patient experienced a spontaneous abortion at approximately 5 to 6 weeks gestation. The patient completed maintenance therapy and is in remission 8 months after the end of treatment. The second patient, known to be non-compliant during therapy, was found to be 5 months pregnant at the end of maintenance therapy. She developed HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count), was induced at approximately 34 weeks, and delivered an apparently normal baby girl. Both the patient and her baby continue to do well 10 months after delivery.

CONCLUSIONS

A variety of factors may influence the incidence of pregnancy during ALL therapy. Gonadal function, which is likely to return to normal during maintenance therapy, may also be affected by alterations in the dose intensity of treatment. Social factors may also alter the incidence of pregnancy. Adverse effects on the fetus are more likely to occur in the first trimester, depending on the drug or drugs used. Although all chemotherapies may have mutagenic and teratogenic effects, they do not invariably cause abnormalities. Survival of adolescents who become pregnant during treatment does not appear to be adversely affected when therapy is not modified or discontinued.

Bone-marrow transplantation for haematological malignancy in childhood

Twenty-three children with haematological malignancies and a poor prognosis underwent bone-marrow transplantation. Thirteen children had acute lymphoblastic leukaemia, eight had acute nonlymphoblastic leukaemia, one had chronic myeloid leukaemia and one had malignant histiocytosis. One child was in relapse at the time of transplant and 22 were in first or subsequent remission. Before transplantation all patients received cyclophosphamide (60 mg/kg) on two consecutive days followed by total body irradiation given as a single dose of 10 Gy at 0.18 Gy/min (one patient) or 0.07 Gy/min (three patients), or as a fractionated dose of 10-12 Gy at 0.07-0.1 Gy/min (19 patients). One child with malignant histiocytosis also received two doses of etoposide (5 mg/kg). Methotrexate was given after transplantation to prevent or modify graft-versus-host disease (GVHD). One patient who received a transplant in relapse died early from overwhelming bacterial sepsis. Twenty-two patients engrafted, and of these 11 developed acute GVHD; five developed chronic GVHD; seven developed interstitial pneumonitis, with four deaths; and five relapsed between three and 12 months after transplantation, with three deaths. Fifty-nine per cent (13/22) of patients who received a transplant during remission remain in continuous complete remission and 68% (15/22) have survived for a median of 18 months (range, four to 73 months). Bone-marrow transplantation that is undertaken during remission of disease offers a prolonged disease-free survival in selected childhood malignancies.

Results of a pilot study for the treatment of childhood acute nonlymphoblastic leukemia

Eighteen children with acute nonlymphoblastic leukemia were entered on a pilot protocol. The drugs used were vincristine, daunorubicin, cytosine arabinoside, and prednisolone for remission induction, high-dose cyclophosphamide together with vincristine and mercaptopurine for consolidation, and cycles of vincristine, prednisolone, mercaptopurine, methotrexate, and daunorubicin for maintenance therapy. Prophylactic central nervous system therapy (cranial radiotherapy 2400 rad and intrathecal methotrexate 10 mg/m2 for five doses) was given once remission had been achieved. Fourteen of the 18 children (78%) achieved complete remission (CR) and 50% of those achieving CR remain in CR for 35+ to 87+ months. Survival for all children ranges from 2 to 88+ months with 50% remaining alive for 36+ to 88+ months. The protocol was well tolerated with minimal side effects. These results together with those of other recently reported studies indicate an improving prognosis for acute nonlymphoblastic leukemia in childhood.

The treatment of acute myelocytic leukemia in patients 30 years of age and younger

The treatment of acute myelocytic leukemia in childhood and young adults has lagged behind that for acute lymphocytic leukemia. The studies described here were directed towards evaluating the role of intensive chemotherapy in the treatment of this illness. Intensive remission induction therapy combining cytosine arabinoside with an anthracycline antibiotic produced a complete remission rate comparable to that achieved in acute lymphocytic leukemia (45 of 49 patients or 92%). Intensive consolidation chemotherapy produced a median duration of complete remission of 160 weeks with 40% of patients projected to be in remission at 4 years. By contrast, the median duration of remission for patients treated with moderate consolidation/maintenance therapy was 23 weeks with only 10% of patients in remission at 4 years. These studies demonstrate that intensive chemotherapy can be administered to pediatric patients and young adults and that this approach to therapy produces a high remission rate with a 3 year median duration of remission.

Therapy of Acute Nonlymphocytic Leukemia in Children: A Review of 73 Patients

Since 1969, 73 children with acute nonlymphocytic leukemia have been admitted for evaluation and treatment at the Institute of Hematology of the University of Rome. Various drug regimens, basically including daunomycin and/or cytosine arabinoside, were employed both for induction and maintenance treatment. Overall, the incidence of complete remission was 63 %. The availability of intensive supportive measures starting in 1974 appears to be the most likely explanation for the higher response rate observed since then. Duration of remission and overall survival were disappointingly short owing to the high frequency of bone marrow relapse. Carefully controlled clinical studies will in the future be necessary to explore better methods of preventing leukemic relapse.

The cytosine arabinoside (Ara-C) syndrome

Four patients with non-Hodgkin lymphoma and two with acute lymphocytic leukemia (ages 4 and 4 months to 16 years 6 months) exhibited a unique reaction to intravenously administered cytosine arabinoside (Ara-C) given alone as a part of the previously reported LSA2-L2 treatment protocol. The syndrome was characterized by fever, myalgia, bone pain, and occasionally by chest pain, maculopapular rash, and conjunctivitis. Each of the eleven episodes of this syndrome occurred within 6-12 hours of drug infusion and always abated after cessation of Ara-C. Prior to the reaction, patients had been on therapy for an average of 13.5 months during which they were exposed to 2298-5387 mg/m2 (mean of 3200 mg/m2) of Ara-C. The high incidence of this syndrome (50% of our patients on the LSA2-L2 regimen and 33% of those receiving Ara-C) has not been previously reported. Considering the prolonged exposure to Ara-C and our inability to document infections in the patients or pyrogens contaminating the drug lots, the most likely explanation for this syndrome is a hypersensitivity reaction to Ara-C. Prevention of these symptoms with corticosteroids supports this contention and provides a reasonable alternative to discontinuing Ara-C.

Natural history of central nervous system acute leukemia in adults

Central nervous system (CNS) involvement occurred in 45 of 222 (20.3%) leukemic adults achieving bone marrow (BM) complete remission (CR), including 12 of 23 (52%) acute undifferentiated leukemia (AUL), 12 of 32 (39%) lymphoma leukemia, 5 of 26 (19%) acute lymphoblastic leukemia, and 16 of 142 (11%) acute myelogenous leukemia. Risk factors for CNS disease were lactic dehydrogenase (LDH) greater than or equal to 25,000/mm3. AUL morphology, age less than 20 years, and extramedullary involvement were most significant. Pattern of CNS involvement varied with morphology. Survival after CNS relapse depended most on BM status and symptoms. Duration of CNS CR was longest for asymptomatic patients with low CSF cell counts. Also important were duration of first BM CR, ease of achievement of initial BM CR, and leukocyte count (original and at most closely antecedent BM involvement), reflecting the common origin of BM and CNS leukemic cells. Central nervous system relapse generally did not shorten BM CR or survival, although early primary CNS relapse was associated with early BM relapse.

Acute nonlymphocytic leukemia

The discovery of cytosine arabinoside, and then the anthrocycline antibiotics, 6-thioguanine, vincristine, cyclophosphamide, and other drugs, has added to the armamentarium of known effective agents. The use of combination chemotherapy, the recognition of the need during induction for virtual marrow aplasia to obtain a remission, and recognition of the predilection of the disease for the central nervous system requiring prophylaxis constitute major advances. The impediment to long-term survival is the lack of effective maintenance therapy.

Improved survival in young children with acute granulocytic leukemia treated with combination therapy using cyclophosphamide, oncovin, cytosine arabinoside, and prednisone

Seven of 17 children (41%) under 5 years of age with acute granulocytic leukemia (AGL) treated with either cytosine arabinoside-cytoxan (CA-CYT) or Mini-COAP (CA-CYT with vincristine sulfate [VCR] and prednisone) have been in continuous complete remission 4 years or more. CA and CYT were each given in the dosage of 120 mg/m2 intravenously, daily in 3 divided doses, for 4 days. Induction consisted of two courses given at intervals of 2 weeks; during maintenance the courses were repeated at intervals of 4 weeks. In the Mini-COAP regimen, standard 28-day VCR-prednisone therapy was superimposed on CA-CYT induction and 4-day VCR-prednisone pulses were superimposed on CA-CYT maintenance. Transient moderate to severe myelosuppression was frequent; other manifestations of toxicity were mild. Administration of drugs at home was feasible in many instances. Mini-COAP was proved to be an effective therapeutic regimen for young children with AGL and should be considered as initial therapy.

Improved remission induction rate with D-ZAPO but unimproved remission duration with addition of immunotherapy to chemotherapy in previously untreated children with ANLL

In 163 children with acute nonlymphocytic leukemia (ANLL), a D-ZAPO induction program consisting of daunomycin, 5-azacytidine, cytosine arabinoside, prednisone, and vincristine resulted in a remission rate of 71.8%. Immunologic therapy was employed during maintenance with the aim of prolonging remission and improving survival. The administration of immunotherapy consisting of a mixture of bacillus Calmette-Guérin (BCG) and allogenic acute myelomonocytic leukemic cells injected intradermally on day 14 of each of the first three monthly cycles of 6-thioguanine for ten days, 5-azacytidine and cytosine arabinoside for four days, and vincristine for one day did not improve remission duration or survival compared to that due to chemotherapy alone. Important prognostic factors identified in this study included a remission induction rate significantly better for females than males (P = 0.04), for children between the ages of 5 and 10 years compared to those greater than this age group (P = 0.01), and a prolonged remission duration (P = 0.04), and survival (P less than 0.01) for patients with initial white blood counts of less than 20 x 10(9)/liter.