Genetic staging of unresectable or metastatic neuroblastoma in infants: a Pediatric Oncology Group study.

BACKGROUND: Current staging systems for unresectable or metastatic neuroblastoma do not reliably predict responses to chemotherapy in infants under 1 year of age. Previous studies have indicated that the DNA content, or ploidy, of malignant neuroblasts can discriminate between good and poor responders in this group of patients, but the clinical utility of ploidy assessment has remained in question. PURPOSE: We tested, in a prospective nonrandomized study, the hypothesis that neuroblast ploidy could be used as the sole guide for treatment selection in infants with unresectable or metastatic tumors and could differentiate between those who would respond to our previous standard regimen and those who would benefit from an immediate switch to another therapy. METHODS: One hundred seventy-seven infants were enrolled in this trial. Five of these infants were subsequently excluded (two ineligible, two lacking ploidy information, and one protocol violation); therefore, 172 patients were included in the study. One hundred thirty infants with hyperdiploid tumors (DNA index > 1.0; better prognosis in retrospective studies) were treated with a well-tolerated regimen of cyclophosphamide (150 mg/m2 per day orally or intravenously on days 1-7) and doxorubicin (35 mg/m2 intravenously on day 8). Forty-two infants with diploid tumors (DNA index = 1.0; worse prognosis in retrospective studies) received cisplatin (90 mg/m2 intravenously on day 1) and teniposide (100 mg/ m2 intravenously on day 3) after an initial course of cyclophosphamide plus doxorubicin. Statistical end points were response and long-term survival. In addition, we assessed within each ploidy group (i.e., patients with hyperdiploid tumors and those with diploid tumors) the prognostic significance of NMYC gene copy number, tumor stage, and other variables commonly measured in this disease. RESULTS: Of the 127 assessable infants with hyperdiploid tumors, 115 (91%) had complete responses--85 after receiving five courses of cyclophosphamide plus doxorubicin and 30 after receiving further therapy including cisplatin plus teniposide. The 3-year survival estimate for the entire hyperdiploid group was 94% (95% confidence interval [CI] = 89%-98%). Nineteen (46%) of 41 assessable infants with diploid tumors were complete responders. The overall 3-year survival estimate for this group was 55% (95% CI = 39%-70%). Prognostic factor analysis indicated that NMYC gene amplification and an elevated serum lactate dehydrogenase level were statistically significant markers of higher risk disease within the diploid group (two-sided P values of .005 and .003, respectively). Only NMYC was predictive in the hyperdiploid group (P = .003). CONCLUSION: Use of a prognostic staging system based on tumor cell ploidy, augmented with the NMYC gene copy number and serum level of lactate dehydrogenase, would very likely improve the treatment of infants with unresectable or metastatic neuroblastoma. Patients with diploid tumors characterized by an amplified NMYC locus represent a particularly unfavorable risk group that may benefit from innovative new therapies.

Phase I study of escalating targeted doses of carboplatin combined with ifosfamide and etoposide in treatment of newly diagnosed pediatric solid tumors.

BACKGROUND: The combination of carboplatin, ifosfamide, and etoposide has shown promising activity in a variety of relapsed childhood solid tumors but has not been studied in newly diagnosed patients. PURPOSE: The tolerance for and activity of escalating targeted doses of carboplatin combined with ifosfamide and etoposide (ICE) were assessed in children with advanced germ cell tumors or other rare solid tumors for which no standard therapy exists. METHODS: Fifteen children with newly diagnosed solid tumors received ICE chemotherapy. Individualized carboplatin doses were calculated to achieve a target area under the concentration x time curve (AUC) and adjusted for the glomerular filtration rate (estimated by 99mTc-labeled diethylene-triamine pentaacetic acid clearance). Cohorts of at least three patients received carboplatin at an initial target AUC of 6 mg.min/mL, with escalations of 2 mg.min/mL in subsequent cohorts. Carboplatin was given on day 1, followed by ifosfamide at 2 g/m2 per day and etoposide at 100 mg/m2 per day on days 2 through 4. All patients received at least two courses of therapy in the absence of progressive disease, and as many as eight courses could be given. RESULTS: The 15 patients received a total of 46 assessable courses of ICE. Myelosuppression was the dominant toxicity; 30 courses (67%) resulted in hospitalization for febrile neutropenia. Neutropenia was dose limiting at the carboplatin target AUC of 12 mg.min/mL. One complete and eight partial responses were seen in the 14 assessable patients; two additional patients had at least partial responses documented at surgery or autopsy. Six patients are without evidence of disease at a median of 548 days after diagnosis. CONCLUSION: ICE chemotherapy, with the carboplatin dose based on a target AUC of 10 mg.min/mL, is tolerable and has significant activity in a variety of rare malignancies, including extragonadal germ cell tumors. IMPLICATIONS: The combination of carboplatin, etoposide, and ifosfamide holds promise in the treatment of rare pediatric malignancies.

Clinical relevance of tumor cell ploidy and N-myc gene amplification in childhood neuroblastoma: a Pediatric Oncology Group study.

We assessed tumor cell DNA content (ploidy) and N-myc gene copy number as predictors of long-term disease-free survival in 298 children with neuroblastoma. Diploid tumor stem lines were identified in 101 patients (34%), clonal hyperdiploid abnormalities in 194 (65%), and hypodiploid stem lines in three (1%). In children with widely disseminated tumors at diagnosis (stage D), ploidy had a highly age-dependent influence on prognosis. Among infants (less than 12 months) treated with cyclophosphamide-doxorubicin, hyperdiploidy was closely associated with long-term disease-free survival (greater than 90% of cases), while diploidy invariably predicted early treatment failure (P less than .001). Similarly, in children 12 to 24 months of age who were treated with cisplatin-teniposide and cyclophosphamide-doxorubicin, diploidy uniformly predicted early failure, whereas half of the children with hyperdiploidy achieved long-term disease-free survival (P less than .001). There was no relationship between ploidy and treatment outcome in children older than 24 months with stage D tumors who had a very low probability of long-term disease-free survival (less than 10%). N-myc gene amplification was detected in 37 (25%) of the 147 tumors tested, with the remainder showing single-copy levels of the gene. N-myc gene amplification was more frequent in diploid than in hyperdiploid tumors (23 of 57 v 14 of 87, P = .001) and predicted a high likelihood of early treatment failure. In children younger than 2 years with disseminated neuroblastoma, tumor cell ploidy and N-myc gene copy number provide complementary prognostic information that will distinguish patients who can be cured on current regimens from those who require new treatment strategies.

Secondary acute myeloid leukemia in children previously treated with alkylating agents, intercalating topoisomerase II inhibitors, and irradiation.

PURPOSE: Patient records were reviewed to identify cases of secondary acute myeloid leukemia (AML) with clinical and cytogenetic features characteristic of classic epipodophyllotoxin-related AML in patients whose prior treatment for cancer did not include these agents. PATIENTS AND METHODS: Four cases of secondary AML with chromosomal abnormalities involving bands 11q23 and 21q22, in the absence of prior treatment with etoposide or teniposide, were identified among patients treated at St Jude Children's Research Hospital between January 1980 and April 1992. RESULTS: The four identified patients were initially treated for rhabdomyosarcoma, non-Hodgkin's lymphoma (n = 2), and Hodgkins' disease. Prior chemotherapy included relatively low cumulative doses of doxorubicin (median, 150 mg/m2; range, 120 to 375 mg/m2) and cyclophosphamide (median, 3,100 mg/m2; range, 2,250 to 11,400 mg/m2). All four patients had received radiation therapy: 59.4 Gy to the right middle ear for rhabdomyosarcoma; 15 Gy and 12 Gy to the abdomen and right lower quadrant, respectively, for non-Hodgkin's lymphoma; 27 Gy to the right orbit for non-Hodgkin's lymphoma; and 36.6 Gy to the mantle-paraaortic-spleen regions plus 20.4 Gy inverted-Y radiation at relapse for Hodgkin's disease. Secondary AML was diagnosed a median of 38 months after initial diagnosis (range, 14 to 55). Leukemic cell translocations involved band 11q23 in two cases and band 21q22 in two. Although all patients obtained a complete remission (CR), only one remains disease-free (at 34 months), following an allogeneic bone marrow transplant. CONCLUSION: Intercalating topoisomerase II inhibitors (doxorubicin, dactinomycin), when combined with alkylating agents and irradiation, may cause secondary AML.

Phase I study of escalating targeted doses of carboplatin combined with ifosfamide and etoposide in children with relapsed solid tumors.

PURPOSE: The tolerance of escalating targeted doses of carboplatin combined with ifosfamide (IFOS)/etoposide (VP-16) (ICE) was assessed in children with recurrent solid tumors. PATIENTS AND METHODS: To reduce interpatient variability in carboplatin systemic exposure, 45 children were treated with doses individualized to a target area under the serum concentration versus time curve (AUC) based on renal function, using technetium 99-diethyl-enetriamine pentaacetic acid (99mTc-DTPA) clearance to estimate glomerular filtration rate (GFR). Cohorts of at least three patients received carboplatin at an initial target AUC of 2 mg/mL x min, with escalations of 1 mg/mL x min in subsequent cohorts. Courses consisted of carboplatin on day 1 followed by IFOS 2 g/m2 plus VP-16 100 mg/m2 on days 2 and 3. Patients received at least two courses, with a maximum of eight courses possible in the absence of progressive disease. When only moderate toxicity occurred after escalation to 5 mg/mL x min, a third dose of IFOS plus VP-16 was added. After three patients were treated at this level, carboplatin escalation proceeded. RESULTS: Neutropenia and thrombocytopenia were the dominant toxicities in the 43 assessable patients. At the target AUC of 8 mg/mL x min, 13 of 20 cycles were associated with febrile neutropenia. For phase II trials, we recommend a carboplatin target AUC of 6 mg/mL x min with three doses of IFOS and VP-16 for patients with prior craniospinal irradiation or high-dose cisplatin (CDDP)/VP-16, or 7 mg/mL x min for patients without such histories. There were two complete responses (CRs), 13 partial responses (PRs), and 17 objective responses (ORs). CONCLUSION: The ICE regimen shows promising activity in pediatric solid tumors. The clear relationship between hematologic toxicity and carboplatin systemic exposure supports the use of targeted dosing in further trials of ICE chemotherapy.

Impact of intensified therapy on clinical outcome in infants and children with neuroblastoma: the St Jude Children's Research Hospital experience, 1962 to 1988.

To gauge the impact of intensified therapy on the survival of infants (younger than 1 year, n = 129) and children (greater than or equal to 1 year of age, n = 275) with neuroblastoma, we analyzed the results of eight successive clinical trials comparing various combinations of antineoplastic drugs, surgery, and radiotherapy. Changes in treatment did not affect the survival of children with involved noncontiguous lymph nodes or distant metastatic disease until the combination of cisplatin and teniposide (CDDP/VM26) was added to a basic regimen of cyclophosphamide and doxorubicin (CTX/DOX). The resulting 4-year survival was 28% +/- 5% (SE) compared with 7% +/- 2% for previous treatments (P less than .001 by the log-rank test). The 4-year survival of infants with metastatic disease was improved by administering CTX/DOX to all patients, reserving CDDP/VM26 for those whose disease was resistant to the former combination: 82% +/- 6% versus 45% +/- 8% in earlier studies; P less than .001. In the subset of infants whose tumors had disseminated to bone or bone marrow at diagnosis, this therapeutic approach increased the probability of long-term survival from 48% +/- 10% to 85% +/- 9% (P = .01). The small group of children over 1 year of age with localized unresectable tumors also fared significantly better with the switch to CTX/DOX chemotherapy (4-year survival, 93% +/- 7% v 42% +/- 13%; P = .02). Multivariate analysis indicated that young age, limited-disease stage, nonadrenal primary site, and intensified treatment were independent predictors of a more favorable outcome. We conclude that substantial advances in the treatment of neuroblastoma have occurred over the past 25 years at this institution. The current overall 4-year survival probability of 57% +/- 4% compares favorably with estimates for most other common solid tumors of childhood.

Therapeutic effects and pharmacokinetics of recombinant human granulocyte-macrophage colony-stimulating factor in childhood cancer patients receiving myelosuppressive chemotherapy.

Twenty-five children with refractory solid tumors were given recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) in escalated doses of 60 to 1,500 micrograms/m2 as 2-hour intravenous infusions, beginning 24 hours after myelosuppressive treatment with cisplatin and etoposide. Tolerance to rhGM-CSF was exceptional even at dose levels that exceeded the maximum-tolerated dosage (MTD) reported for adults. The agent produced dose-related increases in platelet and neutrophil counts, resulting in significantly shorter durations of severe neutropenia and thrombocytopenia (P less than .01 for each analysis). At the higher dosages (greater than or equal to 750 micrograms/m2), treatment with rhGM-CSF reduced the median number of days of antibiotic therapy for fever and neutropenia by approximately one half. We conclude that rhGM-CSF is well tolerated by leukopenic children in doses as high as 1,500 micrograms/m2. An MTD was not reached in this study. The ability of the growth factor to reduce severe neutropenia and thrombocytopenia suggests it will have an important role in the management of childhood solid tumors.

Prognostic significance of age, MYCN oncogene amplification, tumor cell ploidy, and histology in 110 infants with stage D(S) neuroblastoma: the pediatric oncology group experience--a pediatric oncology group study.

PURPOSE: Although a high rate of spontaneous regression is observed in infants with stage D(S) neuroblastoma (NB), survival is not uniform. To determine the prognostic relevance of age at diagnosis, therapy, and tumor biology in infants with stage D(S) NB, we reviewed the Pediatric Oncology Group (POG) experience. PATIENTS AND METHODS: A review of patients diagnosed with stage D(S) NB registered on POG protocols was performed. Survival according to age at diagnosis, treatment, and tumor biology was determined. RESULTS: Between 1987 and 1996, 110 infants with stage D(S) NB had an estimated 3-year survival rate of 85% +/- 4%; survival rate was 71% +/- 8% for infants 2 months of age or younger, and 68% +/- 12%, 44% +/- 33%, and 33% +/- 19% for patients with diploid, MYCN-amplified, and unfavorable histology tumors, respectively. Survival rates were similar for patients who received adjuvant chemotherapy versus those who did not (82% +/- 5% v 93% +/- 6%, respectively; P = .187). Furthermore, there was no statistical difference in survival rate for patients who underwent complete resection of their primary tumor compared with those who underwent partial resection or biopsy only (90% +/- 5% v 78% +/- 7%, respectively; P = .083). CONCLUSION: Our review confirmed that the survival of infants with stage D(S) NB is excellent. However, subsets of patients with poor prognosis can be identified by young age and unfavorable biologic factors. More effective therapy is needed for the group of stage D(S) infants who show unfavorable clinical and biologic features.

Late effects of treatment in survivors of childhood acute myeloid leukemia.

PURPOSE: To investigate the incidence of and risk factors for late sequelae of treatment in patients who survived for more than 10 years after the diagnosis of childhood acute myeloid leukemia (AML). PATIENTS AND METHODS: Of 77 survivors (median follow-up duration, 16. 7 years), 44 (group A) had received chemotherapy, 18 (group B) had received chemotherapy and cranial irradiation, and 15 (group C) had received chemotherapy, total-body irradiation, and allogeneic bone marrow transplantation. Late complications, tobacco use, and health insurance status were assessed. RESULTS: Growth abnormalities were found in 51% of survivors, neurocognitive abnormalities in 30%, transfusion-acquired hepatitis in 28%, endocrine abnormalities in 16%, cataracts in 12%, and cardiac abnormalities in 8%. Younger age at the time of diagnosis or initiation of radiation therapy, higher dose of radiation, and treatment in groups B and C were risk factors for the development of academic difficulties and greater decrease in height Z: score. In addition, treatment in group C was a risk factor for a greater decrease in weight Z: score and the development of growth-hormone deficiency, hypothyroidism, hypogonadism, infertility, and cataracts. The estimated cumulative risk of a second malignancy at 20 years after diagnosis was 1.8% (95% confidence interval, 0.3% to 11.8%). Twenty-two patients (29%) were smokers, and 11 (14%) had no medical insurance at the time of last follow-up. CONCLUSION: Late sequelae are common in long-term survivors of childhood AML. Our findings should be useful in defining areas for surveillance of and intervention for late sequelae and in assessing the risk of individual late effects on the basis of age and history of treatment.

Direct translation of a protracted irinotecan schedule from a xenograft model to a phase I trial in children.

PURPOSE: In a preclinical model of neuroblastoma, administration of irinotecan daily 5 days per week for 2 consecutive weeks ([qd x 5] x 2) resulted in greater antitumor activity than did a single 5-day course with the same total dose. We evaluated this protracted schedule in children. PATIENTS AND METHODS: Twenty-three children with refractory solid tumors were enrolled onto a phase I study. Cohorts received irinotecan by 1-hour intravenous infusion at 20, 24, or 29 mg/m(2) (qd x 5) x 2 every 21 days. RESULTS: The 23 children (median age, 14.1 years; median prior regimens, two) received 84 courses. Predominant diagnoses were neuroblastoma (n = 5), osteosarcoma (n = 5), and rhabdomyosarcoma (n = 4). The dose-limiting toxicity was grade 3/4 diarrhea and/or abdominal cramps in six of 12 patients treated at 24 mg/m(2), despite aggressive use of loperamide. The maximum-tolerated dose (MTD) on this schedule was 20 mg/m(2)/d. Five patients had partial responses and 16 had disease stabilization. On day 1, the median systemic exposure to SN-38 (the active metabolite of irinotecan) at the MTD was 106 ng-h/mL (range, 41 to 421 ng-h/mL). CONCLUSION: This protracted schedule is well tolerated in children. The absence of significant myelosuppression and encouraging clinical responses suggest compellingly that irinotecan be further evaluated in children using the (qd x 5) x 2 schedule, beginning at a dose of 20 mg/m(2). These results imply that data obtained from xenograft models can be effectively integrated into the design of clinical trials.

Late effects in survivors of infant leukemia.

Little is known about the incidence of and risk factor for late effects of infant leukemia. We evaluated 19 children with acute lymphoblastic leukemia and 15 with acute myeloid leukemia who were diagnosed at age 12 months or younger and have survived for more than 5 years after the diagnosis (median length of follow-up, 13 years; range, 5.7-29 years). Ten patients received chemotherapy alone (group A), 17 received chemotherapy and CNS-directed radiation therapy (CRT) (group B), and seven received chemotherapy, CRT and bone marrow transplantation (group C). The most frequently observed late sequelae included problems in growth (66% of survivors), learning (50%), hypothyroidism (15%), and pubertal development (12%). Cataract, cardiac and hearing abnormalities occurred in 6% of patients. Only eight patients (24%) survive without late effects. In comparison to patients in group A, patients in groups B and C had a higher incidence of having at least one late complication (P = 0.009), a greater decrease in height Z score at 5 years after diagnosis (P = 0.023), and a higher incidence of academic difficulties (P = 0.004). The estimated odds of academic difficulties increased by 18% (P = 0.032) for each month younger in age at the time of CRT. These results indicate that late sequelae are common in longterm survivors of infant leukemia and are often related to CRT and the patient's age at the time of CRT.

Interleukin-2 gene-modified allogeneic tumor cells for treatment of relapsed neuroblastoma.

Tumor cells that have been genetically modified to express immunostimulatory genes will induce effective antitumor responses in a range of syngeneic animal models. For human applications, transduced autologous tumor cell lines are often difficult or impossible to prepare, so that there are strong incentives for substituting a standardized allogeneic tumor cell line. However, such lines may be inferior immunogens if they differ from host tumors in the antigens they express. We have evaluated the safety, immunostimulatory, and antitumor activity of an interleukin-2-secreting allogeneic neuroblastoma cell line in 12 children with relapsed stage IV neuroblastoma. They received two to four subcutaneous injections of cells in a dose-escalating schedule, up to a maximum of 10(8) cells per injection. There was induration and pruritus at the injection site, and skin biopsies revealed mild panniculitis with CD3+ cells surrounding scanty residual tumor cells. There was a limited but significant peripheral monocytosis. No patient showed any increase in direct cytotoxic effector function against the immunizing cell line, but 3 patients had a rise in the frequency of neuroblastoma-reactive cytotoxic T lymphocyte precursor cells. One child had > 90% tumor response (PR), 7 had stable disease, and 4 had progressive disease in response to vaccine alone. Although these results offer some encouragement for the continued pursuit of allogeneic vaccine strategies in human cancer, the antitumor immune responses we observed are inferior to those obtained in an earlier immunization study using autologous neuroblastoma cells. Hence, we suggest that this earlier approach remains preferable, its difficulties notwithstanding.

Detection of MYCN gene amplification in neuroblastoma by fluorescence in situ hybridization: a pediatric oncology group study.

To assess the utility of fluorescence in situ hybridization (FISH) for analysis of MYCN gene amplification in neuroblastoma, we compared this assay with Southern blot analysis using tumor specimens collected from 232 patients with presenting characteristics typical of this disease. The FISH technique identified MYCN amplification in 47 cases, compared with 39 by Southern blotting, thus increasing the total number of positive cases by 21%. The major cause of discordancy was a low fraction of tumor cells (< or =30% replacement) in clinical specimens, which prevented an accurate estimate of MYCN copy number by Southern blotting. With FISH, by contrast, it was possible to analyze multiple interphase nuclei of tumor cells, regardless of the proportion of normal peripheral blood, bone marrow, or stromal cells in clinical samples. Thus, FISH could be performed accurately with very small numbers of tumor cells from touch preparations of needle biopsies. Moreover, this procedure allowed us to discern the heterogeneous pattern of MYCN amplification that is characteristic of neuroblastoma. We conclude that FISH improves the detection of MYCN gene amplification in childhood neuroblastomas in a clinical setting, thus facilitating therapeutic decisions based on the presence or absence of this prognostically important biologic marker.

Etoposide pharmacokinetics and pharmacodynamics after acute and chronic exposure to cisplatin.

PURPOSE: The objectives of this study were to determine etoposide pharmacokinetics after both acute and chronic exposure to cisplatin and to evaluate the relationship between etoposide systemic exposure and toxicity in children with neuroblastoma. PATIENTS AND METHODS: Seventeen children with newly diagnosed stage C or D neuroblastoma were given continuous infusions of 780 mg/m2 etoposide over 72 hours as part of multiagent chemotherapy. Etoposide pharmacokinetic parameters were estimated on three occasions in each patient: (1) 21 days after the first cisplatin dose (etoposide was given immediately after cyclophosphamide; cumulative cisplatin dose, 90 mg/m2), (2) 2 days after the third cisplatin dose (cumulative cisplatin dose, 270 mg/m2), and (3) 21 days after the final cisplatin dose (etoposide again immediately after cyclophosphamide; cumulative cisplatin dose, 360 mg/m2). Toxicity was scored on the basis of transfusion requirements and need for hospitalization. RESULTS: Etoposide systemic clearance decreased acutely when administered 2 days after cisplatin (median of 15.5 ml/min/m2) compared with both the first study (20.0 ml/min/m2) and the third study (19.7 ml/min/m2; p < 0.001). The decrease in clearance resulted in a median 31% increase in etoposide area under the concentration-time curve (AUC) compared with the first study and a 36% increase compared with the third study. Toxicity scores were higher after the second study than after the first or third study (p = 0.01), and etoposide AUC was significantly correlated with toxicity score (p = 0.006). Neither etoposide renal clearance nor catechol excretion differed significantly among the courses. CONCLUSION: There was an acute decrease in etoposide systemic clearance when etoposide immediately followed cisplatin. No persistent decrease in etoposide clearance was noted after a cumulative dose of 360 mg/m2 cisplatin. Etoposide AUC was positively correlated with toxicity in a multidrug regimen.

Local tumor control in rhabdomyosarcoma following low-dose irradiation: comparison of group II and select group III patients.

PURPOSE: To determine whether low-dose irradiation (i.e., approximately 40 Gy at 1.5-1.8 Gy/fraction), which is associated with > or = 90% local control in children with initially resected rhabdomyosarcoma and microscopic residual [Intergroup Rhabdomyosarcoma (IRS) group II disease], achieves comparable results in children with locally advanced rhabdomyosarcoma (IRS group III) left with microscopic disease after induction chemotherapy with or without delayed surgery. METHODS AND MATERIALS: Among 103 patients entered on five successive studies between 1968 and 1991, 24 had evidence of microscopic residual disease after initial surgical resection (IRS group II) and received low-dose irradiation. Initial chemotherapy was used in 79 with IRS group III disease. In 28 of these 79 group III patients, chemotherapy alone (n = 16) or in combination with delayed surgery (n = 12) reduced disease to microscopic levels prior to the start of radiotherapy based upon which they received low-dose irradiation. All have a minimum 2-year follow-up and median age of 4 years. Primary tumor sites among the 24 with group II disease included: orbit (5), parameningeal (2), nonparameningeal head and neck (3), genitourinary: nonbladder/prostate (5), extremity (4), and other (5). Irradiation dose ranged from 32-50 Gy, with a median and modal dose of 40 Gy. Primary tumor sites among the 28 with group III disease selectively treated with low-dose irradiation included: orbit (1), parameningeal (6), nonparameningeal head and neck (4), genitourinary: bladder/prostate (12) and nonbladder/prostate (1), extremity (1), and other (3). Irradiation dose ranged from 33-52 Gy, with a median and modal dose of 40 Gy. RESULTS: Local disease control has been maintained in 23 of 24 patients (96%) with group II disease. Local control occurred in eight of nine (89%) group II patients receiving < 40 Gy and in all 15 receiving > or = 40 Gy (p = 0.26). Twenty (83%) are alive and free of disease. Twenty-two of the 28 patients (79%) with group III disease treated with low-dose irradiation have maintained continuous local control of disease which was not statistically different from the group II patients (p = 0.08). Local control occurred in 7 of 11 (64%) group III patients receiving < 40 Gy vs. 15 of 17 (88%) receiving > or = 40 Gy (p < = 0.14). Nineteen (68%) are alive and free of disease. Survival in these group III patients is significantly worse than that of the group II patients, with 19 (68%) alive and free of disease (p = 0.04). CONCLUSION: Children with locally advanced rhabdomyosarcoma (IRS group III) who have only microscopic disease after induction chemotherapy with or without delayed surgery have a high likelihood of achieving local control with low-dose irradiation. For this group, data suggest treatment to a dose level of at least 40 Gy.

Effect of HLA class I or class II incompatibility in pediatric marrow transplantation from unrelated and related donors.

The degree of histoincompatibility that can be tolerated, and the relative importance of matching at individual HLA class I and class II locus in bone marrow transplantation (BMT) has not been established. We hypothesized that matching for HLA-DR may not be more important than matching for HLA-A or HLA-B in selection of a donor for successful BMT. We retrospectively analyzed the outcomes of 248 consecutive pediatric patients who received allogeneic BMT from related donors (RD, n = 119) or unrelated donors (URD, n = 129). HLA-A and HLA-B were serologically matched, and HLA-DRB1 were identical by DNA typing in 69% of donor-recipient pairs. Most patients (89%) had hematologic malignancies; the rest had aplastic anemia or a congenital disorder. One HLA-A antigen mismatch was associated with a decrease in survival (p = 0.003) and a delay in granulocyte engraftment (p = 0.02) in recipients of RD marrow; as well as a decrease in survival (p = 0.02) and the development of severe acute graft-versus-host disease (GVHD) (p = 0.03) in recipients of URD marrow. One HLA-B antigen mismatch was associated with a decrease in the survival (p = 0.05) and the development of severe GVHD (p = 0.0007) in recipients of RD marrow. One HLA-DRB1 allele mismatch was associated only with a decrease in the survival (p = 0.0003) of recipients of RD marrow. Results of this study suggest that disparity in HLA-A and HLA-B antigens may not be better tolerated than disparity in HLA-DR allele in allogeneic BMT. Further studies are warranted to confirm our results.

Formation and stability of vincristine-tubulin complex in kidney cytosols. Role of GTP and GTP hydrolysis.

Vincristine-tubulin complex formed in the 100,000 g fraction of mouse kidney dissociated rapidly at 37 degrees in the absence of guanosine-5'-triphosphate (GTP). In the presence of 2 mM GTP, there was a substantial (2.8-fold) increase in complex stability; NaF (100 mM) but not beta-glycerophosphate (1 mM) also reduced the rate of dissociation. Further, complex was stabilized by other ribonucleoside-5'-triphosphates (but not their respective 5'-monophosphates), and a nonhydrolyzable analogue of GTP. Stability of the VCR-tubulin complex formed in cytosol from kidney and separated from unbound VCR and GTP by gel filtration was influenced by the concentration of GTP. These results appear not to be a consequence of denaturation of tubulin during incubation, as VCR binding activity remained constant under experimental conditions both in the presence and after the removal of GTP. Further, the rate of formation of the VCR-tubulin complex in kidney was also influenced by the concentration of GTP and was increased by the addition of NaF. In the absence of added GTP, virtually no complex was isolated. ATP, CTP, or ITP has little effect on complex formation, suggesting that the effect may be GTP specific. These data suggest that the destabilizing activity in cytosols prepared from mouse kidney, and the failure to form a stable VCR-tubulin complex in kidney, are in part the consequence of rapid hydrolysis of GTP by a pyrophosphohydrolase. Direct measurement of the hydrolysis of GTP showed that the activity in kidney (9.26 nmol/min/mg protein) was 9.3-fold greater than in tumor extracts.

Escalating sequential high-dose carboplatin and etoposide with autologous marrow support in children with relapsed solid tumors.

Thirty patients with relapsed pediatric solid tumors received high-dose carboplatin and etoposide with autologous marrow support in a dose-escalation trial. These patients had received extensive prior treatment, which included both cisplatin and etoposide in 25 cases. Six patient cohorts received carboplatin in doses of 1200-2100 mg/m2 and etoposide in doses of 960-1500 mg/m2. All courses were associated with severe neutropenia and thrombocytopenia. The median times from bone marrow infusion to granulocyte recovery (> 0.5 x 10(9)/l) and platelet recovery (> 50 x 10(9)/l) were 33 and 28 days, respectively, with similar findings for all dosage levels. The frequency of non-hematologic toxicities was generally low, although hyponatremia (Na+ < 129 mEq/l) was seen in one-third of the courses. Hepatoxicity was dose-limiting and was significantly associated with the cumulative prior cisplatin dose (p = 0.006). There were four toxic deaths (CNS hemorrhage, alfa-streptococcal sepsis, Candida sepsis, and enterocolitis). Eleven patients received a second course of therapy; toxicity profiles and times to hematologic recovery were similar for the two courses. Clinical responses were observed at all dosage levels. Eleven of 26 evaluable patients achieved a clinical response (one complete, 10 partial). The majority of responses were in patients with neuroblastoma (six of 16) or Hodgkin's disease (two of three). For phase II clinical trials, we recommend dosages of 2100 mg/m2 of carboplatin and 1500 mg/m2 of etoposide for children with prior cumulative cisplatin exposure < 960 mg/m2. This carboplatin dose represents a three- to four-fold increase over pediatric doses tolerated without bone marrow support.

Allogeneic bone marrow transplantation for infants with acute leukemia or myelodysplastic syndrome.

The objective of this study is to investigate the outcome of children 24 months of age or younger (infants) at the time of allogeneic bone marrow transplantation (BMT) for acute leukemia or myelodysplasia. We analyzed the survival rate, prognostic factors, incidences of late sequelae, and immune reconstitution in 22 infants who underwent allogeneic BMT. The 5-year event-free survival estimate was 45.5% (95% confidence interval (CI), 24.4% to 63.3%). Six patients died of transplant-related complications and six died of disease relapse. Remission status at the time of BMT was the most important prognostic factor (P = 0.005): no patient who received a transplant while their disease was not in remission survived, whereas the 5-year survival estimate for infants who underwent BMT during remission was 56% (95% CI, 31% to 75%). Long-term outcomes in the 10 infant survivors were compared with those of 10 older controls matched for diagnosis, disease status at the time of BMT, calendar year at the time of BMT, and source of stem cells. Immune function 1 year after transplantation and the incidences and spectra of late sequelae were similar for both groups during a median of 3.5 years (range, 1.5 to 7.2 years) of follow-up.

Bone marrow transplantation for therapy-induced acute myeloid leukemia in children with previous lymphoid malignancies.

Twenty-one children who developed therapy-related acute myeloid leukemia after treatment for acute lymphoblastic leukemia received allogeneic bone marrow transplants between January 1990 and June 1997. All had previously received epipodophyllotoxin-containing regimens and 11 had cytogenetic abnormalities involving 11q23. Induction chemotherapy was given to 13 patients and eight patients went directly to BMT. Eleven received marrow from matched siblings, eight from matched unrelated donors and two from haploidentical family members. Conditioning regimens included cyclophosphamide (CY), cytarabine, and total body irradiation. Four patients are alive disease-free between 1118 and 1825 days post-BMT resulting in a 3-year DFS of 19%. Ten patients relapsed at a median of 150 days (range 30-664 days) post-BMT and all eventually died of disease. Seven patients died of regimen-related toxicity. The outlook for patients with therapy-related AML/MDS remains poor and more effective therapy is needed.