High-dose thiotepa and etoposide-based regimens with autologous hematopoietic support for high-risk or recurrent CNS tumors in children and adults

A comprehensive understanding of thioTEPA metabolism in the mouse using UPLC-ESI-QTOFMS-based metabolomics

ThioTEPA, an alkylating agent with anti-tumor activity, has been used as an effective anticancer drug since the 1950s. However, a complete understanding of how its alkylating activity relates to clinical efficacy has not been achieved, the total urinary excretion of thioTEPA and its metabolites is not resolved, and the mechanism of formation of the potentially toxic metabolites S-carboxymethylcysteine (SCMC) and thiodiglycolic acid (TDGA) remains unclear. In this study, the metabolism of thioTEPA in a mouse model was comprehensively investigated using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) based-metabolomics. The nine metabolites identified in mouse urine suggest that thioTEPA underwent ring-opening, N-dechloroethylation, and conjugation reactions in vivo. SCMC and TDGA, two downstream thioTEPA metabolites, were produced from thioTEPA from two novel metabolites 1,2,3-trichloroTEPA (VII) and dechloroethyltrichloroTEPA (VIII). SCMC and TDGA excretion were increased about 4-fold and 2-fold, respectively, in urine following the thioTEPA treatment. The main mouse metabolites of thioTEPA in vivo were TEPA (II), monochloroTEPA (III) and thioTEPA-mercapturate (IV). In addition, five thioTEPA metabolites were detected in serum and all shared similar disposition. Although thioTEPA has a unique chemical structure which is not maintained in the majority of its metabolites, metabolomic analysis of its biotransformation greatly contributed to the investigation of thioTEPA metabolism in vivo, and provides useful information to understand comprehensively the pharmacological activity and potential toxicity of thioTEPA in the clinic.

Fludarabine allows dose reduction for total body irradiation in pediatric hematopoietic stem cell transplantation

PURPOSE

To examine, in the setting of total body irradiation (TBI) for the preparation of pediatric hematopoietic stem cell transplantation (HSCT), whether TBI dose can be reduced without compromising the efficacy of a regimen consisting of fludarabine and radiotherapy; and whether there is any increased risk of pulmonary toxicity due to the radiosensitizing effect of fludarabine.

METHODS AND MATERIALS

A total of 52 pediatric patients with hematologic malignancies received TBI-based conditioning regimens in preparation for allogeneic HSCT. Twenty-three patients received 12 Gy in 4 daily fractions in combination with cyclophosphamide, either alone or with other chemotherapeutic and biologic agents. Twenty-nine patients received 9 Gy in 3 fractions in conjunction with fludarabine and melphalan. Clinical and radiation records were reviewed to determine engraftment, pulmonary toxicity (according to Radiation Therapy Oncology Group criteria), transplant-related mortality, recurrence of primary disease, and overall survival.

RESULTS

The two groups of patients had comparable pretransplant clinical characteristics. For the 12-Gy and 9-Gy regimens, the engraftment (89% and 93%; p = 0.82), freedom from life-threatening pulmonary events (65% and 79%; p = 0.33), freedom from relapse (60% and 73%; p = 0.24), and overall survival (26% and 47%; p = 0.09) were not statistically different.

CONCLUSIONS

The addition of fludarabine and melphalan seems to allow the dose of TBI to be lowered to 9 Gy without loss of engraftment or antitumor efficacy.

Use of high-dose chemotherapy in front-line therapy of childhood malignant glioma

Brain tumors are the second most common cancer in pediatric patients and the main cause from death of malignant tumors in this age group. High-grade or malignant glioma, among which anaplastic astrocytomas and glioblastoma are the most prevalent histotypes, represent 10% of pediatric brain tumors and, taken as a whole, are the second most frequent malignant histotype after medulloblastoma. Apart from complete excision followed by full-dose local radiotherapy, chemotherapy appears to provide some benefit to the final outcome. Different trials have explored the role of high-dose chemotherapy that, theoretically, could give an advantage to these patients by overcoming the blood-brain barrier, cell chemoresistance and inducing a wider number of responses. However, it is still doubtful if more responses translate into better outcome and it is not fully understood which patients can experience a true benefit from this treatment strategy. New protocols under evaluation include new agents with specific biological targets, multiple cycles of high-dose chemotherapy, and vaccination, as an immunotherapeutic approach.

Pilot study of tandem high-dose chemotherapy and autologous stem cell transplantation with a novel combination of regimens in patients with poor risk lymphoma

In an effort to improve the outcome of poor-risk lymphoma patients, we evaluated a novel regimen of tandem high-dose chemotherapy (THDC) with autologous stem cell transplantation. A total of 41 patients (median age 40 years, range 15-68 years) with poor-risk non-Hodgkin's lymphoma and Hodgkin's disease were enrolled. THDC consisted of melphalan (180 mg/m2) and escalating dose mitoxantrone (30-50 mg/m2) (MMt) for the first conditioning regimen, and thiotepa (500 mg/m2), carboplatin (800 mg/m2), and escalating dose etoposide phosphate (400-850 mg/m2), (ETCb) as the second regimen. In all, 31 patients (76%) completed both transplants, with a median time between transplants of 55 days (range 26-120). The maximum tolerated dose was determined as 40 mg/m2 for mitoxantrone and 550 mg/m2 for etoposide phosphate. The overall toxic death rate was 12%. Following high-dose chemotherapy, 10 of 24 evaluable patients (42%) were in CR. The two-year overall survival and event-free survival is 67% (95% CI, 52-81%) and 45%, (95% CI, 29-61%) for the 41 patients enrolled; and 69% (95% CI, 525-586%) and 48% (95% CI, 30-67%) for the 31 patients completing both transplants. This THDC regimen is feasible but with notable toxicity in heavily pretreated patients; its role in the current treatment of high-risk lymphoma remains to be determined.

Sequential chemotherapy, high-dose thiotepa, circulating progenitor cell rescue, and radiotherapy for childhood high-grade glioma

Childhood malignant gliomas are rare, but their clinical behavior is almost as aggressive as in adults, with resistance to therapy, rapid progression, and not uncommonly, dissemination. Our study protocol incorporated sequential chemotherapy and high-dose thiotepa in the preradiant phase, followed by focal radiotherapy and maintenance with vincristine and lomustine for a total duration of one year. The induction treatment consisted of two courses of cisplatin (30 mg/m2) plus etoposide (150 mg/m2) x 3 days and of vincristine (1.4 mg/m2) plus cyclophosphamide (1.5 g/m2) plus high-dose methotrexate (8 g/m2), followed by high-dose thiotepa (300 mg/m2 x 3 doses), with harvesting of peripheral blood progenitor cells after the first cisplatin/etoposide course. From August 1996 to March 2003, 21 children, 14 females and 7 males, with a median age of 10 years were enrolled, 18 presenting with residual disease after surgery. Histologies were glioblastoma multiforme in 10, anaplastic astrocytoma in nine, and anaplastic oligodendroglioma in two; sites of origin were supratentorial areas in 17, spine in two, and posterior fossa in two. Of the 21 patients, 12 have died (10 after relapse, with a median time to progression for the whole series of 14 months; one with intratumoral bleeding at 40 months after diagnosis; and one affected by Turcot syndrome for duodenal cancer relapse). Four of 12 relapsed children had tumor dissemination. At a median follow-up of 57 months, overall survival and progression-free survival at four years were 43% and 46%, respectively. Sequential and high-dose chemotherapy can be afforded in front-line therapy of childhood malignant glioma without excessive morbidity and rather encouraging results.

A pilot trial of tandem autologous peripheral blood progenitor cell transplantation following high-dose thiotepa and carboplatin in children with poor-risk central nervous system tumors

This is a pilot study performed to determine the maximum tolerated number of courses of high-dose thiotepa and carboplatin with autologous peripheral blood progenitor cell (PBPC) transplantation in poor-risk pediatric central nervous system (CNS) tumor patients. Twelve patients were enrolled and a total of 24 PBPC transplants were performed. The median age was 7.7 years. All patients had CNS tumors: 4 relapsed CNS PNET, 2 high-risk PNET in first remission, 2 relapsed/progressive brainstem tumor, 2 relapsed/progressive anaplastic astrocytoma, 1 relapsed GBM, and 1 recurrent ependymoma. The regimen consisted of thiotepa 250 mg/m2/day x 3 days and carboplatin 400 mg/m2/day x 3 days. No toxic deaths occurred. All patients were hospitalized for a median duration of 17 days. The median number of CD34 cells infused was 5.4 x 10(6)/kg (2.1-29.7 x 10(6)/kg) per course. Median time to ANC > 0.5 x 10(9)/L was 9 days, and platelets > 20 x 10(9)/L was 13.5 days. Four patients came off protocol after only one course of PBPC (2 had tumor progression, 2 parental choice); 4 patients underwent two, and 4 patients three courses of PBPC. Major nonhematologic complications were mucositis that necessitated infusion of narcotics (11/24 courses), fever of unknown origin (12/24), documented infection (9/24), and hemorrhagic cystitis (3/24). TPN was administered during 22 of 24 courses with a median duration of 15 days. It isfeasible to administer 2-3 courses of tandem high-dose thiotepa and carboplatin with PBPC transplant with prompt engraftment and manageable toxicities in pediatric CNS tumor patients.

High-dose thiotepa and etoposide in children with poor-prognosis brain tumors

BACKGROUND

Outcome data were analyzed for 27 patients who were affected with recurrent or newly diagnosed high-risk brain tumors and who underwent high-dose chemotherapy with triethylenethiophosphoramide (thiotepa) and etoposide in addition to autologous stem cell transplantation between May 1992 and September 2002.

METHODS

Fifteen males and 12 females (median age, 11 years) were included in the study. Twelve patients had newly diagnosed high-risk brain tumors, and 15 patients had recurrent brain tumors. The conditioning regimen consisted of thiotepa 900 mg/m2 and etoposide 1500 mg/m2 over 3 days starting on Day -5. Stem cell rescue was performed using bone marrow (BM) in 8 patients, peripheral blood stem cells (PBSCs) in 18 patients, and BM and PBSCs in 1 patient.

RESULTS

For the BM group, neutrophil (PMN) engraftment was achieved on Day +14 (median value), whereas platelet (PLT) engraftment was achieved on Day +68 (median value). One patient did not achieve PLT engraftment. For the PBSC group, the PMN engraftment was achieved on Day +10.0 (median value), and the PLT engraftment was achieved on Day +15.5 (median value). Transplantation-related toxicity (evaluated using the Bearman score) included Grade 2-3 mucositis in 16 patients, Grade 1 kidney toxicity in 6 patients, Grade 1 liver toxicity in 6 patients, and Grade 2 liver toxicity in 1 patient. Transplantation-related mortality was observed in 1 patient (3.6%), who died of Candida pneumonia. The 3-year overall survival (OS) rate was 44.6%, and the 3-year event-free survival (EFS) rate was 31%. There was a statistically significant difference in OS and EFS rates for patients who underwent ASCT and achieved complete remission compared with patients who had measurable disease.

CONCLUSIONS

The results of the current study suggest that high-dose chemotherapy followed by ASCT may be beneficial for patients who achieve complete remission before ASCT, whereas for other patients, new strategies are required.

High-dose chemotherapy with autologous stem cell rescue in children with retinoblastoma

Children with metastatic retinoblastoma are considered to have a poor prognosis after conventional chemotherapy. We used high-dose chemotherapy (HDC) with peripheral hematopoietic stem cell transplantation in such patients in an attempt to improve their survival. Four patients with bone marrow metastases and one child with extraorbital disease were treated with HDC after achieving complete remission by enucleation and conventional chemotherapy. The child with extraorbital tumor was the only one to receive local irradiation. The conditioning regimen included thiotepa (900 mg/m(2)), etoposide (40 mg/kg) and carboplatin (1.5 g/m(2)) in four patients, and BCNU (300 mg/m(2)), cyclophosphamide (6.8 g/m(2)) and etoposide (1.6 g/m(2)) in one child. Hematologic recovery occurred without delay in all patients. The main toxicities were diarrhea, mucositis and infectious complications. No toxic deaths or any major late toxicities were observed. The child treated with the BCNU regimen developed a meningeal relapse 10 months after HDC, which was partially resected and treated with conventional chemotherapy, but not with radiotherapy. He is in complete remission (CR) 105 months off treatment. The other patients are in CCR for 107, 57, 9 and 8 months after HDC. HDC with thiotepa, etoposide and carboplatin may represent a curative option for children with extrabulbar or disseminated retinoblastoma responsive to chemotherapy. It may control occult CNS disease. The necessity to irradiate these children and the curative potential of this strategy for patients with bulky CNS disease remain to be determined.

High-dose chemotherapy with autologous stem cell rescue for brain tumors

The use of high-dose chemotherapy with stem cell rescue for malignant brain tumors is reviewed. Promising results have been reported in patients with medulloblastomas, supratentorial PNET's and high-grade astrocytomas. Results thus far have been disappointing for ependymomas and brain stem gliomas. The role of this treatment strategy for other chemotherapy-sensitive tumors such as oligodendrogliomas and central nervous system germ cell tumors has yet to be determined.

Feasibility of four consecutive high-dose chemotherapy cycles with stem-cell rescue for patients with newly diagnosed medulloblastoma or supratentorial primitive neuroectodermal tumor after craniospinal radiotherapy: results of a collaborative study

PURPOSE

This study was designed to determine the feasibility and safety of delivering four consecutive cycles of high-dose cyclophosphamide, cisplatin, and vincristine, each followed by stem-cell rescue, every 4 weeks, after completion of risk-adapted craniospinal irradiation to children with newly diagnosed medulloblastoma or supratentorial primitive neuroectodermal tumor (PNET).

PATIENTS AND METHODS

Fifty-three patients, 19 with high-risk disease and 34 with average-risk disease, were enrolled onto this study. After surgical resection, high-risk patients were treated with topotecan in a 6-week phase II window followed by craniospinal radiation therapy and four cycles of high-dose cyclophosphamide (4,000 mg/m2 per cycle), with cisplatin (75 mg/m2 per cycle), and vincristine (two 1.5-mg/m2 doses per cycle). Support with peripheral blood stem cells or bone marrow and with granulocyte colony-stimulating factor was administered after each cycle of high-dose chemotherapy. Treatment of average-risk patients consisted of surgical resection and craniospinal irradiation, followed by the same chemotherapy given to patients with high-risk disease. The expected duration of the chemotherapy was 16 weeks, with a cumulative cyclophosphamide dose of 16,000 mg/m2 and a planned dose-intensity of 1,000 mg/m2/wk.

RESULTS

Fifty of the 53 patients commenced high-dose chemotherapy, and 49 patients completed all four cycles. The median length of chemotherapy cycles one through four was 28, 27, 29, and 28 days, respectively. Engraftment occurred at a median of 14 to 15 days after infusion of stem cells or autologous bone marrow. The intended dose-intensity of cyclophosphamide was 1,000 mg/m2/wk; the median delivered dose-intensity was 1,014, 1,023, 974, and 991 mg/m2/wk for cycles 1 through 4, respectively; associated median relative dose-intensity was 101%, 102%, 97%, and 99%. No deaths were attributable to the toxic effects of high-dose chemotherapy. Early outcome analysis indicates a 2-year progression-free survival of 93.6% +/- 4.7% for the average-risk patients. For the high-risk patients, the 2-year progression-free survival is 73.7% +/- 10.5% from the start of therapy and 84.2% +/- 8.6% from the start of radiation therapy.

CONCLUSION

Administering four consecutive cycles of high-dose chemotherapy with stem-cell support after surgical resection and craniospinal irradiation is feasible in newly diagnosed patients with medulloblastoma/supratentorial PNET with aggressive supportive care. The early outcome results of this approach are very encouraging.

A phase I study of high-dose BCNU, etoposide and escalating-dose thiotepa (BTE) with hematopoietic progenitor cell support in adults with recurrent and high-risk brain tumors

This phase I dose-escalation study was performed to determine the tolerability of three-drug combination high-dose BCNU (B) (450 mg/m2), escalating-dose thiotepa (500-800 mg/m2) and etoposide (1200 mg/m2) in divided doses over four days in 22 adults with malignant primary brain tumors. Patients received G-CSF and hematopoeitic support with peripheral blood progenitor cells (PBPC) (n = 18) or both PBPC and marrow (n = 4). The maximum tolerated dose of thiotepa with acceptable toxicity was determined as 800 mg/m2. The 100-day mortality rate was 9% (2/22). Grade III/IV toxicities included mucositis (71%), diarrhea (29%), nausea/vomiting (19%), and hepatic toxicity (14%). Neurological toxicities occurred in 24% and included seizures (two patients) and encephalopathy (three patients). Encephalopathy was transient in two patients and progressive in one patient. All patients had neutropenic fever. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 10 days (range 8-30 days). Platelet engraftment >20 x 10(9)/l occurred after 11 days (range 9-65 days). In the eighteen patients supported solely with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.78, p = 0.001) and platelet engraftment (rho = -0.76, p = 0.002). Overall, 11% of evaluable patients (2/18) had a complete response to BTE. Median time to tumor progression (TTP) was 9 months, with an overall median survival of 17 months. BCNU (450 mg/m2), thiotepa (800 mg/m2) and etoposide (1200 mg/m2) in divided doses over four days is a tolerable combination HDC regimen, the efficacy of which warrants further investigation in adults with optimally resected chemoresponsive brain tumors.