Phase I study of combination topotecan and carboplatin in pediatric solid tumors

Advances in the Management of Neuroblastoma

Neuroblastoma is a malignant tumor of neuroblasts, immature nerve cells found in several areas of the body. It usually affects children under age of 5. As usual, the tumor has ability to grow rapidly and to expand vastly which ultimately leads to death. Mostly, management decisions can be drawn by the prediction of the stage of the disease as well as age at the time of its diagnosis. There are four main stages of neuroblastoma, and treatment is according to the low and high risk of the disease. Several cytotoxic agents along with other therapies (antibody therapy, gene therapy, and even immunological therapies, antiangiogenic therapy, etc.) are used. Immunotherapy also has an important treatment option used nowadays for neuroblastoma. The discovery of major neuroblastoma-predisposition gene anaplastic lymphoma kinase cause somatic transformation or gene strengthening in diagnosed neuroblastoma. Promising new antiangiogenic strategies have also been introduced for the treatment of neuroblastoma with multiple mylomas. To manage numerous myelomas and cancers, including neuroblastoma, bone marrow transplantation and peripheral blood stem cell transplantation may be used.

Topotecan/carboplatin regimen for refractory/recurrent rhabdomyosarcoma in children: Report from the AIEOP Soft Tissue Sarcoma Committee

INTRODUCTION

From 2002 to 2011, the Italian Soft Tissue Sarcoma Committee explored a combination of topotecan and carboplatin as a second-line strategy for children with resistant or relapsing rhabdomyosarcoma.

METHODS

Patients received two blocks of topotecan 2 mg/m2 on days 1, 2, and 3, and carboplatin 250 mg/m2 on days 4 and 5, followed by alternating blocks of topotecan-cyclophosphamide and carboplatin-etoposide for a total of six courses with 3-week intervals. Tumor response was assessed after two cycles, and local control was implemented when feasible.

RESULTS

A total of 38 patients were included in this study: 18/38 had alveolar rhabdomyosarcoma (RMS), 10/38 had metastatic disease at diagnosis, 8/38 had tumor progression during first-line chemotherapy, 21/38 had locoregional relapses, and 9/38 had distant relapses. Thirty-two patients could be assessed for tumor response to topotecan-carboplatin, and 9 (28%) showed a complete or partial response. Twenty-four patients experienced grade IV hematologic toxicity, while transient grade 1 tubulopathy, grade 3 mucositis, transient grade 2 nephrotoxicity, and a grade 2 decline in cardiac function occurred in one patient each. The 5-year overall and progression-free survival rates were 17% and 14%, respectively.

CONCLUSION

the prognosis for children with resistant or relapsing RMS remains unsatisfactory. The topotecan-carboplatin regimen was well-tolerated. Though in case of late relapse the response rate was similar to those reported for other regimes, the result achieved remains unsatisfactory. New approaches, possibly including target agents, seem more attractive for future studies.

Periocular topotecan for vitreous seeds in retinoblastoma

Purpose:

Refractory or recurrent vitreous seeds account for a large proportion of failure of eye salvage in retinoblastoma. The purpose of this study is to evaluate the efficacy of periocular topotecan (POT) in the management of vitreous seeds in retinoblastoma.

Methods:

Retrospective, interventional study of patients with retinoblastoma with vitreous seeds who received POT concurrent with intravenous chemotherapy (IVC).

Results:

Thirty-eight eyes of 35 patients received POT. Five eyes (13%) belonged to International Classification of Retinoblastoma group C, 23 eyes (61%) belonged to group D, and 10 eyes (26%) belonged to group E. Primary treatment included IVC with a combination of carboplatin, etoposide, and vincristine for a mean of 6 cycles (median 6; range 6–9). Concurrent to IVC from the fourth cycle onward, all patients received POT. Focal vitreous seeds were present in 20 eyes (53%) which received a mean of 3 injections (median 3; range 1–7). Diffuse vitreous seeds were present in 18 eyes (47%) which received a mean of 4 injections (median 5; range 1–7). At a mean follow-up of 8.5 months (median 5 months; range 1–15 months), regression of focal and diffuse vitreous seeds was achieved in 16 eyes (80%) and 8 eyes (44%), respectively. In all, 24 eyes (63%) had complete remission of vitreous seeds with POT given concurrently with IVC. Eye salvage was possible in 19 eyes (95%) with focal vitreous seeds and 12 eyes (68%) with diffuse VS. Enucleation was necessary for persistent vitreous seeds and viable tumor in five eyes (13%), viable tumor alone in one eye (0.02%), and recurrent vitreous seeds in one eye (0.02%). None of the patients developed systemic metastasis.

Conclusion:

POT administered concurrent with IVC is safe and effective in the initial management of vitreous seeds.

Outcomes of Patients With Relapsed Hepatoblastoma Enrolled on Children's Oncology Group (COG) Phase I and II Studies

Data are limited regarding outcomes of patients treated for relapsed hepatoblastoma. We reviewed enrollment patterns and outcomes of patients with hepatoblastoma on Children's Oncology Group (COG) phase I/II studies. The medical literature was searched for reports of COG phase I/II studies using PUBMED as well as an inventory from the COG publications office searching manuscripts published from 2000 to 2014. Seventy-one patients with relapsed hepatoblastoma were enrolled on 23 separate COG phase I/II studies. Four studies collected α-fetoprotein (AFP) data, but none utilized AFP decline in assessing response. Most studies enrolled few patients with relapsed hepatoblastoma: 7 studies enrolled 1 patient, and another 7 studies enrolled 2 patients each. Only 9 studies enrolled 3 or more patients with relapsed hepatoblastoma. Four responses were reported. Dedicated strata and/or focus on 1 or 2 studies with compelling biological or clinical rationale for hepatoblastoma may improve accrual (and statistical significance of response data) of patients with relapsed hepatoblastoma. Prospective study of AFP decline versus RECIST response could help determine the optimal method of assessing response to identify potentially beneficial treatments in hepatoblastoma.

A novel trial of topotecan, ifosfamide, and carboplatin (TIC) in children with recurrent solid tumors

BACKGROUND

Ifosfamide, carboplatin, and etoposide (ICE) in children with refractory or recurrent solid tumors and lymphomas has resulted in good overall response rates (ORR). Etoposide, a topoisomerase-II inhibitor, however, has been associated with a significant increase in secondary leukemia. The rationale for substituting topotecan, a topoisomerase-I inhibitor, for etoposide in this regimen, a topoisomerase-II inhibitor, includes its limited toxicity profile and decreased leukemogenicity. Furthermore, topotecan in combination with both alkylators and platinating agents are additive and/or synergistic against a variety of solid tumors.

PROCEDURE

Patients with relapsed/refractory solid tumors received ifosfamide (9 g/m² ) and carboplatin (area under the curve: 3 mg/ml/min). Topotecan was also administered at 0.5 mg/m² /day × 3 days (N = 12) and in a small cohort (N = 3) at 0.75 mg/m² /day.

RESULTS

Fifteen patients were entered onto study. Two patients developed seizures/encephalitis secondary to ifosfamide. One patient had dose-limiting thrombocytopenia secondary to TIC that resolved with supportive care. Patients received a median of three cycles (1-3) of TIC. Of the 14 evaluable patients for response, 4/14 had a complete response (CR), 2/14 had a partial response (PR), and 1/14 patients had stable disease (SD). The ORR (CR + PR) was 43%.

CONCLUSION

TIC chemotherapy is feasible and tolerable in children and adolescents with refractory/recurrent solid tumors and lymphomas and results in a 43% excellent ORR in this poor-risk group of patients. A larger cohort of patients, especially in Wilms tumor and central nervous system (CNS) tumors, should be studied in the future to attempt to confirm these preliminary findings. Pediatr Blood Cancer 2015;62:274-278. © 2014 Wiley Periodicals, Inc.

Relapsed hepatoblastoma

Successful treatment of recurrent hepatoblastoma (HB) relies largely on surgical resection. When tumors are responsive, chemotherapy can be used to render patients resectable. Various chemotherapeutic regimens studied in small numbers of patients on phase I/II trials have shown few responses. The best available data indicate that doxorubicin, if not given during intial treatment, and irinotecan are the most active agents in recurrent HB. Stem cell transplantation and radiation therapy have been reported in several patients with unclear successes. Advances in therapy for relapsed patients require concentrating enrollment in one or two phase I/II trials utilizing agents with promising preclinical data.

Subconjunctival carboplatin and systemic topotecan treatment in preclinical models of retinoblastoma

BACKGROUND

The authors demonstrated previously that the combination of topotecan (TPT) and carboplatin (CBP) was more effective than current chemotherapeutic combinations used to treat retinoblastoma in an orthotopic xenograft model. However, systemic coadministration of these agents is not ideal, because both agents cause dose-limiting myelosuppression in children.

METHODS

To overcome the toxicity associated with systemic TPT and CBP, the authors explored subconjunctival delivery of TPT or CBP in an orthotopic xenograft model and in a genetic mouse model of retinoblastoma (Chx10-Cre;Rb(lox/lox);p107(-/-);p53(lox/lox)). The effects of combined subconjunctival CBP (CBP(subcon)) and systemic TPT (TPT(syst)) were compared with the effects of combined TPT(subcon) and CBP(syst.) at clinically relevant dosages.

RESULTS

Pharmacokinetic and tumor-response studies, including analyses of ocular and hematopoietic toxicity, revealed that CBP(subcon)/TPT(syst) was more effective and had fewer side effects than TPT(subcon)/CBP(syst).

CONCLUSIONS

For the first time, retinoblastoma was ablated and long-term vision was preserved in a mouse model by using a clinically relevant chemotherapy regimen. These results eventually may be translated into a clinical trial for children with this debilitating cancer.

Phase 1 study of oxaliplatin and irinotecan in pediatric patients with refractory solid tumors: a children's oncology group study

BACKGROUND

For this report, the authors estimated the maximum tolerated dose (MTD) and investigated the toxicities of oxaliplatin combined with irinotecan in children with refractory solid tumors.

METHODS

Oxaliplatin was administered on Days 1 and 8 in combination with irinotecan on Days 1 through 5 and Days 8 through 12 of a 21-day cycle. An oral cephalosporin was administered daily to ameliorate irinotecan-associated diarrhea. Pharmacokinetic studies of oxaliplatin and uridine diphosphate glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) genotyping were performed.

RESULTS

Thirteen patients were enrolled. Dose-limiting diarrhea (n = 3), serum lipase elevation (n = 3), serum amylase elevation (n = 2), colitis, abdominal pain, and headache (n = 1 each) occurred at the first dose level (oxaliplatin at a dose of 60 mg/m(2); irinotecan at a dose of 20 mg/m(2)). Only 1 of 7 patients who received reduced doses of both agents (40 mg/m(2)/dose oxaliplatin; 15 mg/m(2)/dose irinotecan) experienced a dose-limiting toxicity (DLT): diarrhea. When the oxaliplatin dose was re-escalated (60 mg/m(2)) with irinotecan at a dose of 15 mg/m(2), 2 of 3 patients had a DLT (1 episode of diarrhea, 1 episode of hypokalemia). Myelosuppression was minimal. One patient had a complete response, and another patient had stable disease for 6 cycles of therapy. The median oxaliplatin area under the concentration versus time curve (AUC(0-->infinity)) was 5.9 microg . hour/mL (range, 1.8-7.6 microg . hour/mL). The frequency of the 6/6, 6/7, and 7/7 UGT1A1 promoter genotypes was 5 of 10, 4 of 10, and 1 of 10, respectively.

CONCLUSIONS

The oxaliplatin MTD was 40 mg/m(2) per dose on Days 1 and 8 in combination with irinotecan 15 mg/m(2) per dose on Days 1-5 and Days 8-12. There was some evidence of antitumor activity; however, severe toxicity, both expected (diarrhea) and unexpected (elevation in pancreatic enzymes), was observed.

Topotecan treatment and its toxic effects on hematologic parameters and trace elements

The aim of this study was to investigate the effects of topotecan, a topoisomerase I-inhibiting anticancer agent, on hematologic parameters and serum levels of trace elements. The study was conducted on three groups consisting of 16 and 18 rabbits in the study groups and 15 rabbits in the control group. Rabbits in group I (n = 16) received high-dose topotecan intravenously (i.v.; 0.5 mg/kg once daily), while rabbits in group II (n = 18) received low-dose topotecan i.v. (0.25 mg/kg once daily) for 3 days. The 15 rabbits comprising the control group did not receive topotecan. Serum samples were collected from each rabbit on the first day, before the treatment, and on the 15th day of treatment. Erythrocytes, hemoglobin, white blood cell count, thrombocyte count, and trace elements such as selenium, copper, lead, zinc, and cobalt were analyzed. Hemoglobin levels and erythrocyte counts were lower in both study groups than in the control group. However, thrombocyte and leukocyte counts were similar in all three groups (p > 0.005). Serum trace element levels (copper, lead, zinc, and cobalt) did not differ significantly between groups. However, serum selenium levels were significantly lower in both study groups than the control group (p < 0.001). The results revealed that topotecan treatment causes a decrease in erythrocyte counts and hemoglobin levels due to bone marrow suppression, and these effects must be taken into account during treatment. In addition, selenium supplementation might be helpful in cancer patients receiving topotecan to increase the effect of the chemotherapeutic agent.

Treatment of retinoblastoma: Current status and future perspectives

Treatment of retinoblastoma must be individualized. Most patients with unilateral, non-metastatic retinoblastoma can be cured with enucleation alone. In patients with histologic risk factors, adjuvant chemotherapy is recommended, with the addition of orbital radiation for patients with trans-scleral involvement or tumor present at the level of the cut end of the optic nerve. Patients with metastases require intensive chemotherapy and consolidation with autologous hematopoietic stem cell rescue. Patients with bilateral or multifocal disease represent a major challenge. Cure of the disease is the first priority, but the therapeutic approach also has to consider eye and vision preservation. The approach is conservative, and only eyes with very advanced disease are enucleated upfront. Patients are treated with chemotherapy and intensive focal treatments, with the aim of delaying or avoiding radiation therapy and enucleation. For patients with early intraocular stage (Reese-Ellsworth groups I-III and International Groups A-B), the two-drug combination of vincristine and carboplatin is recommended. Patients with more advanced intraocular disease (Reese-Ellsworth groups IV-V and International Groups C-D) require more intensive chemotherapy. Standard of care for these patients incorporates etoposide into the regimen. Effective agents with good intraocular penetration, such as topotecan, are being investigated. Because most failures are secondary to progression of the vitreous seeds, subconjunctival carboplatin is added in cases with poor response of the vitreous tumors. Patients must be monitored very closely, with examinations under anesthesia every 4 to 6 weeks, and focal treatments are applied during the procedure. These include cryotherapy for small anterior tumors, thermotherapy and laser photocoagulation for small posterior tumors, and brachytherapy for larger tumors. New treatment approaches under development include the refinement of periocular chemotherapy administration using slow-release devices, the use of suicide gene therapy with local delivery of the herpes simplex thyrosine kinase gene (followed by systemic administration of ganciclovir), and the development of small-molecule inhibitors of the MDMX-p53 interaction.

Population pharmacokinetic analysis of topotecan in pediatric cancer patients

PURPOSE

To characterize the population pharmacokinetics of topotecan lactone in children with cancer and identify covariates related to topotecan disposition.

PATIENTS AND METHODS

The study population consisted of 162 children in seven clinical trials receiving single agent topotecan as a 30-min infusion. A population approach via nonlinear mixed effects modeling was used to conduct the analysis.

RESULTS

A two-compartment model was fit to topotecan lactone plasma concentrations (n = 1874), and large pharmacokinetic variability was observed among studies, among individuals, and within individuals. We conducted a covariate analysis using demographics, biochemical data, trial effects, and concomitant drugs. The most significant covariate was body surface area, which explained 54% of the interindividual variability for topotecan systemic clearance. Interoccasion variability was considerable in both clearance and volume (20% and 22%, respectively), but was less than interindividual variability in both variables. Other covariates related to clearance were concomitant phenytoin, calculated glomerular filtration rate, and age (<0.5 years). Including them in the model reduced the interindividual variability for topotecan clearance by an additional 48% relative to the body surface area-normalized model. The full covariate model explained 76% and 50% of interindividual variability in topotecan clearance and volume, respectively.

CONCLUSIONS

We developed a descriptive and robust population pharmacokinetic model which identified patient covariates that account for topotecan disposition in pediatric patients. Additionally, dosing topotecan based on the covariate model led to a more accurate and precise estimation topotecan systemic exposure compared with a fixed dosing approach, and could be a tool to assist clinicians to individualize topotecan dosing.

Methylation of CASP8, DCR2, and HIN-1 in neuroblastoma is associated with poor outcome

PURPOSE

Epigenetic aberrations have been shown to play an important role in the pathogenesis of most cancers. To investigate the clinical significance of epigenetic changes in neuroblastoma, we evaluated the relationship between clinicopathologic variables and the pattern of gene methylation in neuroblastoma cell lines and tumors.

EXPERIMENTAL DESIGN

Methylation-specific PCR was used to evaluate the gene methylation status of 19 genes in 14 neuroblastoma cell lines and 8 genes in 70 primary neuroblastoma tumors. Associations between gene methylation, established prognostic factors, and outcome were evaluated. Log-rank tests were used to identify the number of methylated genes that was most predictive of overall survival.

RESULTS

Epigenetic changes were detected in the neuroblastoma cell lines and primary tumors, although the pattern of methylation varied. Eight of the 19 genes analyzed were methylated in >70% of the cell lines. Epigenetic changes of four genes were detected in only small numbers of cell lines. None of the cell lines had methylation of the other seven genes analyzed. In primary neuroblastoma tumors, high-risk disease and poor outcome were associated with methylation of DCR2, CASP8, and HIN-1 individually. Although methylation of the other five individual genes was not predictive of poor outcome, a trend toward decreased survival was seen in patients with a methylation phenotype, defined as > or =4 methylated genes (P = 0.055).

CONCLUSION

Our study indicates that clinically aggressive neuroblastoma tumors have aberrant methylation of multiple genes and provides a rationale for exploring treatment strategies that include demethylating agents.

A strategy for controlling potential interactions between natural health products and chemotherapy: a review in pediatric oncology

The high prevalence of complementary and alternative medicine use including natural health products (NHPs) in the pediatric oncology population is well established. The potential for concurrent use of NHPs with conventional chemotherapy necessitates physician awareness regarding the potential risks and benefits that might come from this coadministration. Knowledge of interactions between NHPs and chemotherapy is poorly characterized; however, an understanding of potential mechanisms of interaction by researchers and clinicians is important. Concerns regarding the use of antioxidants during chemotherapy are controversial and evidence exists to support both adherents and detractors in this debate. Our review addresses issues regarding potential interactions between NHPs and chemotherapies used in pediatric oncology from a pharmacokinetic and pharmacodynamic perspective. Examples of combinations of NHP and chemotherapies are briefly presented in addition to a strategy to avoid (or induce) a possible interaction between a NHP and chemotherapy. In conclusion, more clinical research is needed to substantiate or preclude the use of NHPs in the treatment of cancer and especially in combination with chemotherapy.

Phase I study of the combination of topotecan and irinotecan in children with refractory solid tumors

PURPOSE

We have shown in xenograft studies that the antitumor activities of topotecan and irinotecan are highly schedule- and dose-dependent, with a high frequency of response at low, protracted dose schedules. Preclinical and clinical data suggest that topotecan and irinotecan have different antitumor activities and mechanisms of resistance, and non-overlapping toxicities, providing a rationale for their combination. Combining both agents may increase the amount of camptothecin delivered to the tumor, without additive toxicity.

METHODS

We conducted a phase I study in children with refractory solid tumors to determine the maximum tolerated dose (MTD) of irinotecan when administered with a targeted systemic exposure (TSE) of topotecan and to define the dose-limiting toxicity (DLT) of this combination. Irinotecan was administered IV over 60 min followed by topotecan over 30 min daily for 5 days for two consecutive weeks. We initially fixed the topotecan-TSE to 80+/-10 ng*h/ml and investigated the ability to escalate irinotecan (starting dose 16 mg/m2/d). Topotecan and irinotecan pharmacokinetics were determined.

RESULTS

Eleven patients (median age 10 years) were enrolled. Owing to DLT, irinotecan was de-escalated to 12 (level -1; n = 3) and 9 (level -2; n = 3) mg/m2/day, and topotecan-TSE was reduced to 60+/-10 ng*h/ml (level -3; n = 2). DLTs were neutropenia (n = 8), typhlitis (n = 5), and skin rash (n = 1). MTD could not be reached. Median (range) irinotecan and topotecan lactone systemic clearances were 50.3 (16.6-76.2) l/h/m2 and 27.6 (14.7-55.9) l/h/m2, respectively. The pharmacokinetics profile of each agent was similar to that seen in previous single agent studies. One patient with neuroblastoma and one with rhabdomyosarcoma had a partial and a complete response, respectively.

CONCLUSION

Despite promising antitumor activity, the combination of topotecan and irinotecan given on a protracted schedule does not warrant further development in children due to unacceptable toxicity.

Topotecan Combination Chemotherapy in Two New Rodent Models of Retinoblastoma

Chemotherapy combined with laser therapy and cryotherapy has improved the ocular salvage rate for children with bilateral retinoblastoma. However, children with late-stage disease often experience recurrence shortly after treatment. To improve the vision salvage rate in advanced bilateral retinoblastoma, we have developed and characterized two new rodent models of retinoblastoma for screening chemotherapeutic drug combinations. The first model is an orthotopic xenograft model in which green fluorescent protein- or luciferase-labeled human retinoblastoma cells are injected into the eyes of newborn rats. The second model uses a replication-incompetent retrovirus (LIA-E(E1A)) encoding the E1A oncogene. Clonal, focal tumors arise from mouse retinal progenitor cells when LIA-E(E1A) is injected into the eyes of newborn p53-/- mice. Using these two models combined with pharmacokinetic studies and cell culture experiments, we have tested the efficacy of topotecan combined with carboplatin and of topotecan combined with vincristine for the treatment of retinoblastoma. The combination of topotecan and carboplatin most effectively halted retinoblastoma progression in our rodent models and was superior to the current triple drug therapy using vincristine, carboplatin, and etoposide. Vincristine had the lowest LC50 in culture but did not reduce tumor growth in our preclinical retinoblastoma models. Taken together, these data suggest that topotecan may be a suitable replacement for etoposide in combination chemotherapy for the treatment of retinoblastoma.

Pharmacokinetic model-predicted anticancer drug concentrations in human tumors

In an era when molecular and targeted anticancer therapeutics is a major focus and when understanding drug dynamics in tumor is critical, it seems advantageous to be able to relate drug concentrations in tumors to corresponding biological end points. To that end, a novel method, based on physiologically based hybrid pharmacokinetic models, is presented to predict human tumor drug concentrations. Such models consist of a forcing function, describing the plasma drug concentration-time profile, which is linked to a model describing drug disposition in tumors. The hybrid models are originally derived from preclinical data and then scaled to humans. Integral to the scale-up procedure is the ability to derive human forcing functions directly from clinical pharmacokinetic data. Three examples of this approach are presented based on preclinical investigations with carboplatin, topotecan, and temozolomide. Translation of these preclinical hybrid models to humans used a Monte Carlo simulation technique that accounted for intrasubject and intersubject variability. Different pharmacokinetic end points, such as the AUC tumor, were extracted from the simulated human tumor drug concentrations to show how the predicted drug concentrations might be used to select drug-dosing regimens. It is believed that this modeling strategy can be used as an aid in the drug development process by providing key insights into drug disposition in tumors and by offering a foundation to optimize drug regimen design.

A phase I and pharmacodynamic study of fludarabine, carboplatin, and topotecan in patients with relapsed, refractory, or high-risk acute leukemia

PURPOSE

A novel regimen designed to maximize antileukemia activity of carboplatin through inhibiting repair of platinum-DNA adducts was conducted in poor prognosis, acute leukemia patients.

EXPERIMENTAL DESIGN

Patients received fludarabine (10 to 15 mg/m(2) x 5 days), carboplatin (area under the curve 10 to 12 by continuous infusion over 5 days), followed by escalated doses of topotecan infused over 72 hours (fludarabine, carboplatin, topotecan regimen). Twenty-eight patients had acute myelogenous leukemia (7 untreated secondary acute myelogenous leukemia, 11 in first relapse, and 10 in second relapse or refractory), 1 patient had refractory/relapsed acute lymphoblastic leukemia, and 2 patients had untreated chronic myelogenous leukemia blast crisis. Six patients had failed an autologous stem cell transplant. Patients ranged from 19 to 76 (median 54) years. Measurement of platinum-DNA adducts were done in serial bone marrow specimens.

RESULTS

Fifteen of 31 patients achieved bone marrow aplasia. Clinical responses included 2 complete response, 4 complete response with persistent thrombocytopenia, and 2 partial response. Prolonged myelosuppression was observed with median time to blood neutrophils >/=200/microl of 28 (0 to 43) days and time to platelets >/=20,000/microl (untransfused) of 40 (24 to 120) days. Grade 3 or greater infections occurred in all of the patients, and there were 2 infection-related deaths. The nonhematologic toxicity profile was acceptable. Five patients subsequently received allografts without early transplant-related mortality. Maximum tolerated dose of fludarabine, carboplatin, topotecan regimen was fludarabine 15 mg/m(2) x 5, carboplatin area under the curve 12, and topotecan 2.55 mg/m(2) over 72 hours. An increase in bone marrow, platinum-DNA adduct formation between the end of carboplatin infusion and 48 hours after the infusion correlated with bone marrow response.

CONCLUSIONS

Fludarabine, carboplatin, topotecan regimen is a promising treatment based on potential pharmacodynamic interactions, which merits additional study in poor prognosis, acute leukemia patients.

A phase II study of topotecan with vincristine and doxorubicin in children with recurrent/refractory neuroblastoma

BACKGROUND

A Phase II trial in children with advanced neuroblastoma was carried out in five Italian institutions to evaluate the antitumor activity and tolerability of topotecan followed by vincristine and doxorubicin.

METHODS

Children older than age 1 year with Stage III or Stage IV neuroblastoma, all of whom had been treated previously with chemotherapy and were diagnosed with either refractory or recurrent disease, were treated with topotecan at an intravenous dose of 1.5 mg/m(2) (the dose was 0.75 mg/m(2) for patients who were treated within 1 year of previous megatherapy) per day for 5 days followed by 48-hour intravenous infusions of 2 mg/m(2) vincristine and 45 mg/m(2) doxorubicin. Cycles of therapy were repeated every 3 weeks.

RESULTS

Twenty-five patients (2 with Stage III disease and 23 with Stage IV disease; 19 with refractory disease and 6 with recurrent disease) were treated with a total of 115 cycles. Four patients had complete responses, 12 patients had partial responses, 4 patients had minor responses or stable disease, and 5 patients had tumor progression. The overall response rate (including complete and partial responses) was 64% (95% confidence interval, 43-82%). Fifteen patients were alive at the time of the current report and were progression free at 4-16 months (median, 9 months) after the first course of this treatment. Toxicity generally was limited to the hematopoietic system. Dose-limiting toxicity was observed in only 1 patient (Grade 4 liver toxicity). There were no deaths due to infectious or toxic causes.

CONCLUSIONS

The topotecan-vincristine-doxorubicin combination was active and well tolerated in previously treated patients with advanced neuroblastoma.

Advances in the diagnosis and treatment of neuroblastoma

Neuroblastoma, a childhood neoplasm arising from neural crest cells, is characterized by a diversity of clinical behavior ranging from spontaneous remission to rapid tumor progression and death. To a large extent, outcome can be predicted by the stage of disease and the age at diagnosis. However, the molecular events responsible for the variability in response to treatment and the rate of tumor growth remain largely unknown. Over the past decade, transformation-linked genetic changes have been identified in neuroblastoma tumors that have contributed to the understanding of tumor predisposition, metastasis, treatment responsiveness, and prognosis. The Children's Oncology Group recently developed a Neuroblastoma Risk Stratification System that is currently in use for treatment stratification purposes, based on clinical and biologic factors that are strongly predictive of outcome. This review discusses the current risk-based treatment approaches for children with neuroblastoma and recent advances in biologic therapy.

[Topotecan for pediatric patients with resistant and recurrent solid tumors]

BACKGROUND

Topotecan is a cytotoxic drug isolated from the Camptotheca acuminata tree (from China). It is able to block the enzyme DNA topoisomerase I and has recently been used in the treatment of pediatric cancer.

OBJECTIVES

To evaluate our preliminary experience with topotecan in the second line treatment of refractory solid tumors in the pediatric age group. PATIENTS AND MEHTODS: We performed a retrospective study of 10 patients with various recurrent solid tumors resistant to first line treatment who were treated with topotecan alone or in association with other chemotherapeutic agents.

RESULTS

Ten patients with recurrent solid tumors or tumors that were refractory to conventional treatment (two neuroblastomas, three rhabdomyosarcoma, two PNET/Ewing's sarcoma, one anaplastic astrocytoma, one soft tissue sarcoma and one synovial sarcoma) were included. Five patients showed favorable responses (two had complete responses, two had partial responses and one had stable disease). Five patients showed no response. All patients showed grade II-IV hematological toxicity.

CONCLUSIONS

In our experience, topotecan is beneficial in some refractory or recurrent solid tumors, especially neuroblastomas and soft tissue sarcomas. Myelosuppression was tolerable with the use of granulocyte colony-stimulating factors. Patients with a complete response to topotecan could benefit from high-dose chemotherapy and autologous stem cell rescue therapy.