Topotecan and etoposide in the treatment of relapsed high-risk neuroblastoma: results of a phase 2 trial

Dendrimer Nanodevices and Gallic Acid as Novel Strategies to Fight Chemoresistance in Neuroblastoma Cells

Human neuroblastoma (NB), a pediatric tumor inclined to relapse, after an initial response to therapy, usually develops resistance. Since several chemotherapeutics exert anticancer effect by increasing reactive oxygen species (ROS), NB cells overproduce antioxidant compounds becoming drugs-resistant. A strategy to sensitize NB cells to chemotherapy involves reducing their antioxidant defenses and inducing ROS overproduction. Concerning this, although affected by several issues that limit their clinical application, antioxidant/pro-oxidant polyphenols, such as gallic acid (GA), showed pro-oxidant anti-cancer effects and low toxicity for healthy cells, in several kind of tumors, not including NB. Herein, for the first time, free GA, two GA-dendrimers, and the dendrimer adopted as GA reservoir were tested on both sensitive and chemoresistant NB cells. The dendrimer device, administered at the dose previously found active versus sensitive NB cells, induced ROS-mediated death also in chemoresistant cells. Free GA proved a dose-dependent ROS-mediated cytotoxicity on both cell populations. Intriguingly, when administered in dendrimer formulations at a dose not cytotoxic for NB cells, GA nullified any pro-oxidant activity of dendrimer. Unfortunately, due to GA, nanoformulations were inactive on NB cells, but GA resized in nanoparticles showed considerable ability in counteracting, at low dose, ROS production and oxidative stress, herein induced by the dendrimer.

Clinical outcomes and prognostic factors to predict treatment response in high risk neuroblastoma patients receiving topotecan and cyclophosphamide containing induction regimen: a prospective multicenter study

BACKGROUND

Neuroblastoma is the most common extra-cranial solid tumor among children. Despite intensive treatment, patients with advanced disease mostly experience dismal outcomes. Here, we proposed the use of topotecan and cyclophosphamide containing induction regimen as an upfront therapy to high risk neuroblastoma patients.

METHODS

Patients with high risk neuroblastoma undergoing ThaiPOG high risk neuroblastoma protocol from 2016 to 2017 were studied. All patients received 6 cycles of induction regimen consisting of 2 cycles topotecan (1.2 mg/m²/day) and cyclophosphamide (400 mg/m²/day) for 5 days followed by cisplatin (50 mg/m²/day) for 4 days combined with etoposide (200 mg/m²/day) for 3 days on the third and fifth cycles and cyclophosphamide (2100 mg/m²/day) for 2 days combined with doxorubicin (25 mg/m²/day) and vincristine (0.67 mg/m²/day) for 3 days on the fourth and sixth cycles. Treatment response after the 5th cycle before surgery and treatment-related toxicities after each topotecan containing induction cycle were evaluated. Relevant prognostic factors were analyzed to measure the treatment response among those patients.

RESULTS

In all, 107 high risk neuroblastoma patients were enrolled in the study. After the 5th cycle of induction regimen, the patients achieved complete response (N = 2), very good partial response (N = 40), partial response (N = 46) and mixed response (N = 19). None of the patients experienced stable disease or disease progression. The most significant prognostic factor was type of healthcare system. The most common adverse effect was febrile neutropenia followed by mucositis, diarrhea and elevated renal function.

CONCLUSION

The topotecan and cyclophosphamide containing induction regimen effectively provides favorable treatment response. The regimen is well tolerated with minimal toxicity among patients with high risk neuroblastoma in Thailand.

A systematic review of re-induction chemotherapy for children with relapsed high-risk neuroblastoma

BACKGROUND

Despite aggressive multimodal therapy, >50% of children with high-risk neuroblastoma (HRNB) relapse. Survival after relapse is rare, and no consensus currently exists on the most effective therapy.

OBJECTIVE

To conduct a systematic review of the literature on effectiveness of re-induction chemotherapy in children with relapsed HRNB.

METHODS

Database searches were performed to identify studies looking at response to 1st line chemotherapy for children >12 months at diagnosis with first relapse of HRNB. Studies not reporting separate outcomes for HRNB patients or of refractory patients only were excluded. Two independent reviewers extracted the data and assessed study quality using a modified Newcastle-Ottawa tool.

RESULTS

Nine studies were identified fitting the inclusion criteria. All except one were single arm cohorts, and two were retrospective database reviews from single centres. One was a multicentre randomised controlled trial. All used a version of the validated International Neuroblastoma Response Criteria with 8 recording best ever response and 1 at a specified time, and 5 had central review. The proportion of relapsed patients varied from 24 to 100% with 30-93% receiving upfront myeloablative therapy. The response rate varied from 6 to 64%; however, because of heterogeneity, studies were not directly comparable, and no single treatment emerged as the most effective re-induction therapy.

CONCLUSIONS

To date, there is no clear superior re-induction therapy for 1st relapse of HRNB. Randomised controlled trials with separate arms for relapsed versus refractory disease are needed to determine optimal re-induction chemotherapy to act as a backbone for testing newer targeted agents.

Glutathione-mediated antioxidant response and aerobic metabolism: two crucial factors involved in determining the multi-drug resistance of high-risk neuroblastoma

Neuroblastoma, a paediatric malignant tumor, is initially sensitive to etoposide, a drug to which many patients develop chemoresistance. In order to investigate the molecular mechanisms responsible for etoposide chemoresistance, HTLA-230, a human MYCN-amplified neuroblastoma cell line, was chronically treated with etoposide at a concentration that in vitro mimics the clinically-used dose. The selected cells (HTLA-Chr) acquire multi-drug resistance (MDR), becoming less sensitive than parental cells to high doses of etoposide or doxorubicin. MDR is due to several mechanisms that together contribute to maintaining non-toxic levels of H₂O₂. In fact, HTLA-Chr cells, while having an efficient aerobic metabolism, are also characterized by an up-regulation of catalase activity and higher levels of reduced glutathione (GSH), a thiol antioxidant compound. The combination of such mechanisms contributes to prevent membrane lipoperoxidation and cell death. Treatment of HTLA-Chr cells with L-Buthionine-sulfoximine, an inhibitor of GSH biosynthesis, markedly reduces their tumorigenic potential that is instead enhanced by the exposure to N-Acetylcysteine, able to promote GSH synthesis.

Collectively, these results demonstrate that GSH and GSH-related responses play a crucial role in the acquisition of MDR and suggest that GSH level monitoring is an efficient strategy to early identify the onset of drug resistance and to control the patient's response to therapy.

Irinotecan-temozolomide with temsirolimus or dinutuximab in children with refractory or relapsed neuroblastoma (COG ANBL1221): an open-label, randomised, phase 2 trial

BACKGROUND

Outcomes for children with relapsed and refractory neuroblastoma are dismal. The combination of irinotecan and temozolomide has activity in these patients, and its acceptable toxicity profile makes it an excellent backbone for study of new agents. We aimed to test the addition of temsirolimus or dinutuximab to irinotecan-temozolomide in patients with relapsed or refractory neuroblastoma.

METHODS

For this open-label, randomised, phase 2 selection design trial of the Children's Oncology Group (COG; ANBL1221), patients had to have histological verification of neuroblastoma or ganglioneuroblastoma at diagnosis or have tumour cells in bone marrow with increased urinary catecholamine concentrations at diagnosis. Patients of any age were eligible at first designation of relapse or progression, or first designation of refractory disease, provided organ function requirements were met. Patients previously treated for refractory or relapsed disease were ineligible. Computer-based randomisation with sequence generation defined by permuted block randomisation (block size two) was used to randomly assign patients (1:1) to irinotecan and temozolomide plus either temsirolimus or dinutuximab, stratified by disease category, previous exposure to anti-GD2 antibody therapy, and tumour MYCN amplification status. Patients in both groups received oral temozolomide (100 mg/m² per dose) and intravenous irinotecan (50 mg/m² per dose) on days 1-5 of 21-day cycles. Patients in the temsirolimus group also received intravenous temsirolimus (35 mg/m² per dose) on days 1 and 8, whereas those in the dinutuximab group received intravenous dinutuximab (17·5 mg/m² per day or 25 mg/m² per day) on days 2-5 plus granulocyte macrophage colony-stimulating factor (250 μg/m² per dose) subcutaneously on days 6-12. Patients were given up to a maximum of 17 cycles of treatment. The primary endpoint was the proportion of patients achieving an objective (complete or partial) response by central review after six cycles of treatment, analysed by intention to treat. Patients, families, and those administering treatment were aware of group assignment. This study is registered with ClinicalTrials.gov, number NCT01767194, and follow-up of the initial cohort is ongoing.

FINDINGS

Between Feb 22, 2013, and March 23, 2015, 36 patients from 27 COG member institutions were enrolled on this groupwide study. One patient was ineligible (alanine aminotransferase concentration was above the required range). Of the remaining 35 patients, 18 were randomly assigned to irinotecan-temozolomide-temsirolimus and 17 to irinotecan-temozolomide-dinutuximab. Median follow-up was 1·26 years (IQR 0·68-1·61) among all eligible participants. Of the 18 patients assigned to irinotecan-temozolomide-temsirolimus, one patient (6%; 95% CI 0·0-16·1) achieved a partial response. Of the 17 patients assigned to irinotecan-temozolomide-dinutuximab, nine (53%; 95% CI 29·2-76·7) had objective responses, including four partial responses and five complete responses. The most common grade 3 or worse adverse events in the temsirolimus group were neutropenia (eight [44%] of 18 patients), anaemia (six [33%]), thrombocytopenia (five [28%]), increased alanine aminotransferase (five [28%]), and hypokalaemia (four [22%]). One of the 17 patients assigned to the dinutuximab group refused treatment after randomisation; the most common grade 3 or worse adverse events in the remaining 16 patients evaluable for safety were pain (seven [44%] of 16), hypokalaemia (six [38%]), neutropenia (four [25%]), thrombocytopenia (four [25%]), anaemia (four [25%]), fever and infection (four [25%]), and hypoxia (four [25%]); one patient had grade 4 hypoxia related to therapy that met protocol-defined criteria for unacceptable toxicity. No deaths attributed to protocol therapy occurred.

INTERPRETATION

Irinotecan-temozolomide-dinutuximab met protocol-defined criteria for selection as the combination meriting further study whereas irinotecan-temozolomide-temsirolimus did not. Irinotecan-temozolomide-dinutuximab shows notable anti-tumour activity in patients with relapsed or refractory neuroblastoma. Further evaluation of biomarkers in a larger cohort of patients might identify those most likely to respond to this chemoimmunotherapeutic regimen.

FUNDING

National Cancer Institute.

Ruthenium(II) polypyridyl complexes with 1,8-naphthalimide group as DNA binder, photonuclease, and dual inhibitors of topoisomerases I and IIα

Two ruthenium(II) polypyridyl complexes containing 1,8-naphthalimide group as DNA binders, photonucleases, and inhibitors of topoisomerases I and IIα are evaluated. The binding properties of [Ru(phen)₂(pnip)]²⁺ {1; phen=1,10-phenanthroline; pnip=12-[N-(p-phenyl)-1,8-napthalimide]- imidazo[4',5'-f] [1,10]phenanthroline} and [Ru(bpy)₂(pnip)]²⁺ (2; bpy=2,2'-bipyridine) with calf thymus DNA increases with increasing the bulkiness and hydrophobic character of ancillary ligands, although the two complexes possess high affinities for DNA via intercalation. Moreover, photoirradiation (λ=365nm) of the two complexes are found to induce strand cleavage of closed circular pBR322 plasmid DNA via singlet oxygen mechanism, while complex 1 displays more effective photocleavage activity than complex 2 under the same conditions. Topoisomerase inhibition and DNA strand passage assay reflect that complexes 1 and 2 are efficient dual poisons of topoisomerases I and IIα.

Additional Therapies to Improve Metastatic Response to Induction Therapy in Children With High-risk Neuroblastoma

Children with high-risk neuroblastoma who fail to achieve adequate metastatic response after induction chemotherapy have dismal outcome and new therapeutic strategies are needed. However, timing of introduction of novel agents still remains under discussion. Given an increase in number of phase I-II studies of molecularly targeted drugs in neuroblastoma, it is crucial to determine, as early as possible, which patients may be suitable candidates for new therapeutic strategies. This single-center retrospective analysis of patients with high-risk neuroblastoma showed that the addition of conventional chemotherapy improved the quality of metastatic response only for the group of patients with partial response. It is therefore proposed to develop stratification criteria for those patients very unlikely to benefit from a plethora of additional lines of treatment, but might benefit from introduction of novel agents.

Association of CYP3A4/5 genotypes and expression with the survival of patients with neuroblastoma

Neuroblastoma (NB) is a rare pediatric disease in Lebanon for which poor prognosis remains a major challenge. Genetic polymorphism of genes coding for drug‑metabolizing enzymes may influence the response of a patient to chemotherapy. This study investigates a possible association between CYP3A4/5 polymorphism and expression levels and survival in NB patients. All patients with stage III and IV NB diagnosed between 1993 and 2012 in three major hospitals in Beirut were included (n=27). Demographic information and survival time were obtained from medical records. CYP3A4 and CYP3A5 genotypes and expression levels were determined in archival tumors by polymerase chain reaction (PCR) and restriction fragment length polymorphism and quantitative PCR, respectively. Additionally, MYCN amplification was assessed. A Cox proportional hazards model was used to evaluate potential associations, adjusting for MYCN amplification. A statistically significant increase in the risk of mortality was observed in patients with MYCN amplification [hazard ratio (HR) 4.11, 95% confidence interval (CI) 1.14‑14.80]. Patients with CYP3A5 expression levels above the median had a lower risk of mortality (HR 0.61, 95% CI 0.21‑1.74) and patients with CYP3A4 expression levels above the median had a higher risk of mortality (HR 2.00, 95% CI 0.67‑5.90). CYP3A5*3/*3 homozygote mutants had a 4.3‑fold increase in the risk of mortality compared with that of homozygote wild‑type or heterozygote mutants (HR 4.30, 95% CI 0.56‑33.30). Carriers of the CYP3A4*1B mutant allele had a 52% lower risk of mortality compared with that of non‑carriers (HR 0.48, 95% CI 0.06‑3.76). Although the results of the present study did not achieve statistical significance, associations were observed, which indicates that CYP3A4 and CYP3A5 may modulate the clinical outcome of NB. Further studies with larger sample sizes are required to characterize the effects of the polymorphism and expression levels of CYP3A4/5 on the survival of patients with NB.

Molecular profiling of childhood cancer: Biomarkers and novel therapies

BACKGROUND

Technological advances including high-throughput sequencing have identified numerous tumor-specific genetic changes in pediatric and adolescent cancers that can be exploited as targets for novel therapies.

SCOPE OF REVIEW

This review provides a detailed overview of recent advances in the application of target-specific therapies for childhood cancers, either as single agents or in combination with other therapies. The review summarizes preclinical evidence on which clinical trials are based, early phase clinical trial results, and the incorporation of predictive biomarkers into clinical practice, according to cancer type.

MAJOR CONCLUSIONS

There is growing evidence that molecularly targeted therapies can valuably add to the arsenal available for treating childhood cancers, particularly when used in combination with other therapies. Nonetheless the introduction of molecularly targeted agents into practice remains challenging, due to the use of unselected populations in some clinical trials, inadequate methods to evaluate efficacy, and the need for improved preclinical models to both evaluate dosing and safety of combination therapies.

GENERAL SIGNIFICANCE

The increasing recognition of the heterogeneity of molecular causes of cancer favors the continued development of molecularly targeted agents, and their transfer to pediatric and adolescent populations.

Treatment with topotecan plus cyclophosphamide in children with first relapse of neuroblastoma

BACKGROUND

Reports of responses and toxicities of salvage therapies for relapsed neuroblastoma are rare and often confounded by effects of additional treatments. Our objective was to describe the outcomes and toxicities for a topotecan and cyclophosphamide (TOPO/CTX) regimen for first relapse or progression of high-risk neuroblastoma.

METHODS

We retrospectively reviewed charts of relapsed or refractory neuroblastoma patients treated between 1999 and 2009 with our standard-of-care outpatient TOPO/CTX (0.75 and 250 mg/m(2) /day × 5 days q3-4 weeks).

RESULTS

Twenty-seven patients received 343 cycles of TOPO/CTX (median 10 cycles per patient, range 1-32). Most patients (N = 25) had undergone autologous stem cell transplantation. Seventeen (63%) patients had an objective response (CR + PR + MR). The 3-year progression-free survival (PFS) after relapse was 11 ± 6% and 3-year overall survival (OS) after relapse was 33 ± 9%. The median PFS was 1.2 years and the median OS was 2.3 years. Five patients are alive with follow-up of 3.1-5.5 years. Shorter time from diagnosis to relapse (6-18 months) was associated with shorter OS. The majority of patients experienced chemotherapy delays, transfusions, and febrile neutropenia, including eight bacterial infections. The mean number of hospitalized days was less than one per cycle.

CONCLUSIONS

TOPO/CTX was well tolerated and resulted in response rates and PFS similar to those reported for patients treated on COG 9462. Our study provides additional toxicity, historical endpoints, and time-to-progression data against which new agents and combination therapies using TOPO/CTX as a backbone can be measured.

Current and future strategies for relapsed neuroblastoma: challenges on the road to precision therapy

More than half of the patients with high-risk neuroblastoma (NB) will relapse despite intensive multimodal therapy, with an additional 10% to 20% refractory to induction chemotherapy. Management of these patients is challenging, given disease heterogeneity, resistance, and organ toxicity including poor hematological reserve. This review will discuss the current treatment options and consider novel therapies on the horizon. Cytotoxic chemotherapy regimens for relapse and refractory NB typically center on the use of the camptothecins, topotecan and irinotecan, in combination with agents such as cyclophosphamide and temozolomide, with objective responses but poor long-term survival. I-meta-iodobenzylguanidine therapy is also effective for relapsed patients with meta-iodobenzylguanidine-avid disease, with objective responses in a third of cases. Immunotherapy with anti-GD2 has recently been incorporated into upfront therapy, but its role in the relapse setting remains uncertain, especially for patients with bulky disease. Future cell-based immunotherapies and other approaches may be able to overcome this limitation. Finally, many novel molecularly targeted agents are in development, some of which show specific promise for NB. Successful incorporation of these agents will require combinations with conventional cytotoxic chemotherapies, as well as the development of predictive biomarkers, to ultimately personalize approaches to patients with "targetable" molecular abnormalities.

Escalating topotecan in combination with treosulfan has acceptable toxicity in advanced pediatric sarcomas

Patients with advanced pediatric sarcomas have a poor prognosis and novel combination therapies are needed to improve the response rates. Hematological and organ related toxicities have been observed when administering topotecan in combination with, e.g., high dose thiotepa. This study evaluates the toxicity of escalating doses of topotecan alone or in combination with thiotepa or treosulfan. We compared the toxicity including death of complication (DOC) of topotecan alone or in combination with thiotepa or treosulfan in advanced pediatric sarcomas (n = 12). Ten of 12 patients (0.83) suffered from advanced tumors of the Ewing family (i.e., bone or marrow metastases or relapse <24 month after diagnosis, including one neuroepithelial tumor of the kidney) and two from alveolar rhabdomyosarcoma stage IV (0.17). Median age was 15 years (range 5-28). Ratio of female to male was 1:1. Two patients received topotecan alone (1.25 mg/m(2) q 5d and 1.5 mg/m(2) q 5d), three patients received four courses of topotecan (2 mg/m(2) q d 1-5) in combination with thiotepa (100 mg/m(2) q d 1-5), and seven patients received topotecan (2 mg/m(2) q d 1-5) in combination with treosulfan (10g/m(2) q d 3-5). Overall toxicity was not different between all three groups; mean scores were 1.6, 1.8, and 1.7 according to WHO grading (Scale 0-4). Organ related toxicity ranged between 0 and 4 and was not different as well. DOC was 0/2, 1/3, and 0/7 patients respectively. Escalating therapy with topotecan in combination with treosulfan has acceptable toxicity and warrants further investigation in advanced pediatric sarcomas.

Ten challenges in the management of neuroblastoma

Neuroblastoma is a complex disease with many contradictions and challenges. It is, by and large, a cancer of babies and preschool children, but it does occur, albeit increasingly rarely, in older children, adolescents and young adults. The prognosis is very variable, with outcome related to age, stage and molecular pathology. Neuroblastoma may behave in an almost benign way, with spontaneous regression in some infants, but the majority of older patients have high-risk disease, which is usually fatal, despite best current treatments. As a rare disease, international collaboration is essential to run clinical trials of adequate statistical power to answer important questions in a reasonable time frame. High-risk disease requires multimodality therapy including chemotherapy, surgery and radiotherapy as well as biological and immunological treatments for optimal outcomes. Innovative treatment approaches, sometimes associated with appreciable toxicity, offer hope for the future but, despite parental wishes, cannot be generally implemented without adequate assessment in clinical trials.

5-day/5-drug myeloablative outpatient regimen for resistant neuroblastoma

5-day/5-drug (5D/5D) is a novel high-dose regimen administered with autologous hematopoietic SCT (HSCT). It was designed to maximize cytoreduction via high dosing of synergistically interacting agents, while minimizing morbidity in patients with resistant neuroblastoma (NB) and ineligible for clinical trials due to myelosuppression from previous therapy. 5D/5D comprises carboplatin 500 mg/m(2)/day on days 1-2, irinotecan 50 mg/m(2)/day on days 1-3, temozolomide 250 mg/m(2)/day on days 1-3, etoposide 200 mg/m(2)/day on days 3-5 and cyclophosphamide 70 mg/kg/day on days 4-5. HSCT is on day 8. Sixteen patients received 21 courses. Treatment was in the outpatient clinic. Responses were noted against progressive disease (PD) that had developed while patients were off, or receiving only low-dose, chemotherapy but not against PD that emerged despite high-dose chemotherapy. Responses were also seen in patients with PD or stable disease after (131)I-metaiodobenzylguanidine therapy. Grade 3 toxicities were limited to transient elevations in liver enzymes (three courses) and hyponatremia (one course). Bacteremia occurred in 2/21 (10%) courses. Hematological recovery allowed patients to be enrolled on clinical trials. In conclusion, 5D/5D (including HSCT) spares vital organs, entails modest morbidity, shows activity against resistant NB and helps patients meet eligibility requirements for formal clinical trials.

Treatment and outcomes of patients with relapsed, high-risk neuroblastoma: results of German trials

BACKGROUND

The prognosis of high-risk neuroblastoma patients has improved over the last decades. However, many patients experience relapse after successful initial treatment. We retrospectively analyzed the long-term outcome of relapsed patients of three consecutive national neuroblastoma trials.

METHODS

Patients were included when they fulfilled all of the following criteria: Age at diagnosis being 1 year or older, first diagnosis between 1990 and 2007, stage 4 disease or stage 3 neuroblastoma with MYCN amplification, and relapse or progression after successful first-line autologous stem cell transplantation (ASCT).

RESULTS

A total of 451 high-risk neuroblastoma patients 1 year or older underwent ASCT during first-line treatment, 253 experienced recurrence of disease, 158 received salvage chemotherapy, and 23 of them finally underwent a second ASCT. These 23 patients had a better median survival (2.08 years) and 3-year survival rate from recurrence (43.5 ± 10.9%) compared to 74 patients who had no second chemotherapy (median survival 0.24 years, 3-year survival rate 4.0 ± 2.6%) and 135 patients who underwent second-line chemotherapy but did not undergo second ASCT (median survival of 0.89 years, 3-year survival rate 9.6 ± 2.8%, P < 0.001). By February 2010, 3/23 patients were in complete remission, 3/23 in very good partial remission, 1/23 in partial remission, 14/23 patients died of disease after successful second ASCT, and 2/23 died of complications due to second ASCT.

CONCLUSION

Intensive second-line therapy is feasible. A small subgroup of relapsed high-risk neuroblastoma patients may benefit from intensive relapse chemotherapy and second ASCT. The potential of long-term survival justifies clinical trials on intensive second-line treatment.

High-dose carboplatin-irinotecan-temozolomide: treatment option for neuroblastoma resistant to topotecan

BACKGROUND

We report a retrospective study of a novel regimen for neuroblastoma (NB) resistant to standard induction or salvage chemotherapy which now routinely includes topotecan.

PATIENTS AND METHODS

Forty-five patients received carboplatin (500 mg/m(2)/day, 2×)-irinotecan (50 mg/m(2)/day, 5×)-temozolomide (250 mg/m(2)/day, 5×) (HD-CIT). Only one course was planned. Patients with thrombocytopenia indicative of poor bone marrow (BM) reserve resulting from extensive prior therapy received peripheral blood stem cells (PBSCs) post-HD-CIT.

RESULTS

Modest acute toxicity allowed outpatient treatment. Low-grade diarrhea was common; there was no mucositis, nephrotoxicity, or cardiotoxicity. Myelosuppression was prolonged but uncomplicated. The absolute neutrophil count reached 500/µl on days 20-30 (median, 25) in 25 patients with satisfactory BM reserve, and on days 9-14 (median, 11) post-PBSC infusion. Anti-NB activity was common against refractory (non-progressing) disease or new relapse occurring off therapy (68% objective response rate), but not against disease progressing on therapy. Seven of 26 patients treated for refractory NB are progression-free and in complete remission following subsequent therapy, including anti-G(D2) immunotherapy, at ≥ 29+ months post-HD-CIT.

CONCLUSIONS

HD-CIT is appealing as salvage or consolidative therapy because of anti-NB activity and modest non-hematologic toxicity. PBSC support is unnecessary when BM reserve is intact. The wide antineoplastic activity of its three components and their potential for activity against disease in the central nervous system support applicability to other cancers.

Do pharmacokinetic polymorphisms explain treatment failure in high-risk patients with neuroblastoma?

PURPOSE

Neuroblastoma is the most common extracranial solid tumour in childhood. It accounts for 15% of all paediatric oncology deaths. In the last few decades, improvement in treatment outcome for high-risk patients has not occurred, with an overall survival rate <30-40%. Many reasons may account for such a low survival rate. The aim of this review is to evaluate whether pharmacogenetic factors can explain treatment failure in neuroblastoma.

METHODS

A literature search based on PubMed's database Medical Subject Headings (MeSH) was performed to retrieve all pertinent publications on current treatment options and new classes of drugs under investigation. One hundred and fifty-eight articles wer reviewed, and relevant data were extracted and summarised.

RESULTS AND CONCLUSIONS

Few of the large number of polymorphisms identified thus far showed an effect on pharmacokinetics that could be considered clinically relevant. Despite their clinical relevance, none of the single nucleotide polymorphisms (SNPs) investigated can explain treatment failure. These findings seem to reflect the clinical context in which anti-tumour drugs are used, i.e. in combination with multimodal therapy. In addition, many pharmacogenetic studies did not assess (differences in) drug exposure, which could contribute to explaining pharmacogenetic associations. Furthermore, it remains unclear whether the significant activity of new drugs on different neuroblastoma cell lines translates into clinical efficacy, irrespective of resistance or myelocytomatosis viral related oncogene, neuroblastoma derived (MYCN) amplification. Elucidation of the clinical role of pharmacogenetic factors in the treatment of neuroblastoma demands an integrated pharmacokinetic-pharmacodynamic approach to the analysis of treatment response data.

Gefitinib in combination with oral topotecan and cyclophosphamide in relapsed neuroblastoma: pharmacological rationale and clinical response

AIM

Activity and toxiciy of gefitinib in combination with topotecan and cyclophosphamide (CPA) were evaluated in a case-series of relapsed neuroblastoma (NB) patients. The in vitro activity of the combination was also assessed.

PROCEDURE

Gefitinib (250 mg/day), topotecan (0.8 mg/m(2)/day), and CPA (50 mg/m(2)/day) (GTC) were administered orally for 14 consecutive days out of 28 days. Antitumor activity of gefitinib as single agent and in combination with either topotecan or CPA was assessed in a panel of NB cell lines.

RESULTS

Ninety-two courses were given in 10 patients. Grade 4 neutropenia was observed in 7/92 courses (8%) and grade 4 thrombocytopenia in 8/92 (9%). Two patients had a grade 2 liver toxicity, four a grade 1/2 skin toxicity, and two a grade 1/2 diarrhea. Dose reduction of topotecan and/or CPA was required in eight patients. After four courses, three patients were in partial response (PR) and four with a stable disease (SD), while three experienced a progressive disease (PD). Time to progression (TTP) was 9 months (range, 1-27). After a median follow-up of 16 months (range 5-54), seven patients are died of disease (DOD) and three alive with disease (AWD). All but one patient discontinued oral chemotherapy because of a PD, whilst one patient stopped chemotherapy after 27 months with a SD. In vitro, gefitinib was synergistic with topotecan and additive with CPA.

CONCLUSION

The GTC combination was well tolerated and the TTP was encouraging. These promising results, also supported by in vitro evidence, should be further confirmed in a phase II study.

Targeting DNA topoisomerase II in cancer chemotherapy

Recent molecular studies have expanded the biological contexts in which topoisomerase II (TOP2) has crucial functions, including DNA replication, transcription and chromosome segregation. Although the biological functions of TOP2 are important for ensuring genomic integrity, the ability to interfere with TOP2 and generate enzyme-mediated DNA damage is an effective strategy for cancer chemotherapy. The molecular tools that have allowed an understanding of the biological functions of TOP2 are also being applied to understanding the details of drug action. These studies promise refined targeting of TOP2 as an effective anticancer strategy.