Recombinant urate oxidase for the prophylaxis or treatment of hyperuricemia in patients With leukemia or lymphoma.

PURPOSE: To improve the control of hyperuricemia in patients with leukemia or lymphoma, we tested a newly developed uricolytic agent, recombinant urate oxidase (SR29142; Rasburicase; Sanofi-Synthelabo, Inc, Paris, France), which catalyzes the oxidation of uric acid to allantoin, a highly water-soluble metabolite readily excreted by the kidneys. PATIENTS AND METHODS: We administered Rasburicase intravenously, at 0.15 or 0.20 mg/kg, for 5 to 7 consecutive days to 131 children, adolescents, and young adults with newly diagnosed leukemia or lymphoma, who either presented with abnormally high plasma uric acid concentrations or had large tumor cell burdens. Blood levels of uric acid, creatinine, phosphorus, and potassium were measured daily. The pharmacokinetics of Rasburicase, the urinary excretion rate of allantoin, and antibodies to Rasburicase were also studied. RESULTS: At either dosage, the recombinant enzyme produced a rapid and sharp decrease in plasma uric acid concentrations in all patients. The median level decreased by 4 hours after treatment, from 9.7 to 1 mg/dL (P =.0001), in the 65 patients who presented with hyperuricemia, and from 4.3 to 0.5 mg/dL (P =.0001) in the remaining 66 patients. Despite cytoreductive chemotherapy, plasma uric acid concentrations remained low throughout the treatment (daily median level, 0.5 mg/dL). The urinary excretion rate of allantoin increased during Rasburicase treatment, peaking on day 3. Serum phosphorus concentrations did not change significantly during the first 3 days of treatment, decreased significantly by day 4 in patients presenting with hyperuricemia (P =.0003), and fell within the normal range in all patients by 48 hours after treatment. Serum creatinine levels decreased significantly after 1 day of treatment in patients with or without hyperuricemia at diagnosis (P =.0003 and P =.02, respectively) and returned to normal range in all patients by day 6 of treatment. Toxicity was negligible, and none of the patients required dialysis. The mean plasma half-lives of the agent were 16.0 +/- 6.3 (SD) hours and 21.1 +/- 12.0 hours, respectively, in patients treated at dosages of 0.15 or 0.20 mg/kg. Seventeen of the 121 assessable patients developed antibodies to the enzyme. CONCLUSION: Rasburicase is safe and highly effective for the prophylaxis or treatment of hyperuricemia in patients with leukemia or lymphoma.

Neurodevelopmental outcome of infants with acute lymphoblastic leukemia: a Children's Cancer Group report.

BACKGROUND: Infants diagnosed with acute lymphoblastic leukemia (ALL) are considered the patient subgroup at the highest risk for central nervous system (CNS) disease, both at presentation and as an isolated extramedullary relapse. In addition, they are highly vulnerable to adverse developmental sequelae from CNS-directed therapy. METHODS: Thirty patients younger than 12 months at diagnosis (12 males, 18 females) in first hematologic remission were evaluated after completion of ALL therapy (mean age = 62.1 months; standard deviation = 17.2 months; range = 38-102 months). CNS-directed treatment included very high dose infusions of methotrexate (MTX) and intrathecal cytarabine and MTX. Three patients had meningeal leukemia that required additional therapy. Children were administered the McCarthy Scales of Children's Abilities, and parents completed a sociodemographic questionnaire to obtain information about occupation and education. RESULTS: Mean scores on all 6 cognitive and motor indices of the McCarthy Scales were in the average range (Verbal = 52.0; Perceptual = 53.6; Quantitative = 49.6; General Cognitive Index [GCI] = 102.1; Memory = 49.2; Motor = 51.0). Score distributions for each neurodevelopmental index were comparable to age-based population standards. One patient obtained a GCI that exceeded 2 standard deviations above the mean; none scored more than 2 standard deviations below. There was no report of developmental disabilities or neurologic disorders for any of the patients. Risk factors, including age at diagnosis, gender, additional CNS-directed treatment, and family socioeconomic status, were not associated with developmental outcome. CONCLUSIONS: Test findings indicated a generally positive neurodevelopmental outcome for ALL patients diagnosed in infancy who were treated with very high dose MTX as CNS-directed therapy. Combined with the reduction in the isolated CNS relapse rate achieved by the Children's Cancer Group (CCG) clinical trial CCG-107, the results of this study represent a substantial improvement in neurodevelopmental outcome for very young patients compared with infants treated for ALL in the past.

Treatment outcome and prognostic factors for infants with acute lymphoblastic leukemia treated on two consecutive trials of the Children's Cancer Group.

PURPOSE: Infants represent a very poor risk group for acute lymphoblastic leukemia (ALL). We report treatment outcome for such patients treated with intensive therapy on consecutive Children's Cancer Group (CCG) protocols. PATIENTS AND METHODS: Between 1984 and 1993, infants with newly diagnosed ALL were enrolled onto CCG-107 (n = 99) and CCG-1883 (n = 135) protocols. Postconsolidation therapy was more intensive on CCG-1883. On both studies, prophylactic treatment of the CNS included both high-dose systemic chemotherapy and intrathecal therapy, in contrast to whole-brain radiotherapy, which was used in earlier studies. RESULTS: Most patients (>95%) achieved remission with induction therapy. The most frequent event was a marrow relapse (46 patients on CCG-107 and 66 patients on CCG- 1883). Four-year event-free survival was 33% (SE = 4.7%) on CCG-107 and 39% (SE = 4.2%) on CCG- 1883. Both studies represent an improvement compared with a 22% (SE = 5.1%) event-free survival for historical controls. Four-year cumulative probabilities of any marrow relapse or an isolated CNS relapse were, respectively, 49% (SE = 5%) and 9% (SE = 3%) on CCG-107 and 50% (SE = 5%) and 3% (SE = 2%) on CCG-1883, compared with 63% (SE = 6%) and 5% (SE = 3%) for the historical controls. Independent adverse prognostic factors were age less than 3 months, WBC count of more than 50,000/microL, CD10 negativity, slow response to induction therapy, and presence of the translocation t(4;11). CONCLUSION: Outcome for infants on CCG-107 and CCG- 1883 improved, compared with historical controls. Marrow relapse remains the primary mode of failure. Isolated CNS relapse rates are low, indicating that intrathecal chemotherapy combined with very-high-dose systemic therapy provides adequate protection of the CNS. The overall unsatisfactory outcome observed for the infant ALL population warrants the future use of novel alternative therapies.

Pharmacology and phase I trial of high-dose oral leucovorin plus 5-fluorouracil in children with refractory cancer: a report from the Children's Cancer Study Group.

Because of the synergy seen in adult trials when 5-fluorouracil is combined with leucovorin, we initiated a Phase I trial of this combination in children's refractory cancer. Leucovorin, an equal mixture of the (6R,S)-diastereoisomers, was administered p.o. for 6 consecutive days as 4 equal doses at 0, 1, 2, and 3 h totaling 500 mg/m2/day. 5-Fluorouracil was given daily on days 2 to 6 as an i.v. bolus immediately following the last dose of leucovorin. The leucovorin dose was held constant while the 5-fluorouracil dose was escalated in cohorts of patients from 300 mg/m2/day to its maximally tolerated dose. Thirty-five patients (19 with acute leukemia and 16 with solid tumors) were evaluable for toxicity. The maximally tolerated dose of FUra was 450 mg/m2/day for 5 treatments for patients with solid tumors and 650 mg/m2/day for 5 treatments for the children with leukemia. The dose-limiting toxicities were myelosuppression and stomatitis. Other side effects included transient, mild elevations of serum transaminases, mild nausea, vomiting, and diarrhea. The pharmacokinetics of high-dose p.o. leucovorin was studied in 23 children. There was considerable interpatient variability in the plasma concentrations of total bioactive folates (TBAF), (6S)-leucovorin, and (6S)-5-methyltetrahydrofolic acid. The maximum plasma concentration (Cmax) of TBAF was 821 +/- 97 (SE) nM, occurring at a median of 8 h; the Cmax of (6S)-leucovorin was 77 +/- 11 nM, occurring at 4 h. The TBAF concentration fell to 146 +/- 42 nM by 24 h. (6S)-5-Methyltetrahydrofolic acid accounted for 90 +/- 7% of the TBAF at the Cmax. The plasma concentration of (6R)-leucovorin, the unnatural isomer, was equal to that of TBAF. Thus, p.o. leucovorin reduced the 5-fold excess of (6R)-leucovorin over TBAF seen after i.v. doses. The relative amounts of the three major plasma species were approximately the same as in adults, even though the Cmax of each compound was lower.

Transient acute hepatotoxicity of high-dose methotrexate therapy during childhood.

Serial liver-enzyme determinations were performed on 36 children with acute lymphoblastic leukemia who were randomized to receive either conventional intrathecal methotrexate (MTX) therapy with cranial irradiation, or an investigational high-dose MTX regimen consisting of 10 courses of 33,600 mg/m2 over 24 hours, with high-dose leucovorin rescue. Both groups of patients received intermittent low-dose oral MTX during maintenance therapy. Serum transaminase elevations in the group of conventionally treated patients were infrequent and moderate in severity (less than 300 IU/liter). In the investigational group, however, the majority of patients had severe, acute increases in SGPT (greater than 300 IU/liter), with peaks up to 1000 to 2000 IU/liter. The incidence and severity of acute transaminasemia were directly proportional to the number of high-dose MTX courses received: courses 1, 2, 3, 4, 5, and 6 caused transaminase elevations in 31%, 50%, 50%, 73%, 100%, and 100% of courses, respectively, and 0%, 14%, 20%, 44%, 55%, and 92%, respectively, were over 300 IU/liter. Patients in both treatment groups developed a pattern of increasing serum alkaline phosphatase concentrations after initiation of low-dose oral MTX therapy; isoenzyme analysis indicated that this effect was osseous rather than hepatic. Serum bilirubin was rarely elevated. Transaminases returned to normal within 1 to 2 weeks after each high-dose MTX treatment, and with follow-up for as long as 7 years, no patient has developed clinical evidence of residual liver disease, after 3 years of high-dose MTX therapy and multiple other antileukemia drugs. The acute hypertransaminasemia frequently observed after high-dose MTX therapy is transient and reversible, and, in children, does not appear to result in chronic liver disease.