Phase II study of gemcitabine in children with solid tumors of mesenchymal and embryonic origin

The triad in current neuroblastoma challenges: Targeting antigens, enhancing effective cytotoxicity and accurate 3D in vitro modelling

Neuroblastoma is an embryonic tumour originating from neural crest cells and accounts for nearly 15 % of all childhood cancer deaths. Despite the implementation of intense multimodal therapy for neuroblastoma, half of the high-risk cohort will relapse with metastatic foci resistant to conventional therapies. There is an urgent need for novel precision medicine approaches to improve patient survival and ensure healthy post-treatment lives for these children. Immunotherapy holds promise for such therapeutics; however, developing effective options has been disappointing despite decades of research. The immunosuppressive tumour-immune microenvironment presents a significant challenge amplified with low mutational burden in neuroblastoma, even with the new discovered tumour antigens. Innovative, practical, and comprehensive approaches are crucial for designing and testing immunotherapies capable of passing clinical trials. Replacing animal models with physiologically relevant in vitro systems will expedite this process and provide new insights into exploitable tumour-immune cell interactions. This review examines this three-pronged approach in neuroblastoma immunotherapy: tumour antigen discovery, immunomodulation, and 3D in vitro tumour models, and discusses current and emerging insights into these strategies to address neuroblastoma immunotherapy challenges.

The Histone Deacetylase Inhibitor Entinostat/Syndax 275 in Osteosarcoma

The prognosis for metastatic osteosarcoma (OS) is poor and has not changed in several decades. Therapeutic paradigms that target and exploit novel molecular pathways are desperately needed. Recent preclinical data suggests that modulation of the Fas/FasL pathway may offer benefit in the treatment of refractory osteosarcoma. Fas and FasL are complimentary receptor-ligand proteins. Fas is expressed in multiple tissues, whereas FasL is restricted to privilege organs, such as the lung. Fas expression has been shown to inversely correlate with the metastatic potential of OS cells; tumor cells which express high levels of Fas have decreased metastatic potential and the ones that reach the lung undergo cell death upon interaction with constitutive FasL in the lung. Agents such as gemcitabine and the HDAC inhibitor, entinostat/Syndax 275, have been shown to upregulate Fas expression on OS cells, potentially leading to decreased OS pulmonary metastasis and improved outcome. Clinical trials are in development to evaluate this combination as a potential treatment option for patients with refractory OS.

Exploiting Signaling Pathways and Immune Targets Beyond the Standard of Care for Ewing Sarcoma

Ewing sarcoma (ES) family of tumors includes bone and soft tissue tumors that are often characterized by a specific translocation between chromosome 11 and 22, resulting in the EWS-FLI1 fusion gene. With the advent of multi-modality treatment including cytotoxic chemotherapy, surgery, and radiation therapy, the prognosis for patients with ES has substantially improved. However, a therapeutic plateau is now reached for both localized and metastatic disease over the last two decades. Burdened by the toxicity limits associated with the current frontline systemic therapy, there is an urgent need for novel targeted therapeutic strategies. In this review, we discuss the current treatment paradigm of ES, and explore preclinical evidence and emerging treatments directed at tumor signaling pathways and immune targets.

Pharmacotherapeutic Management of Wilms Tumor: An Update

Although differences exist in treatment and risk-stratification strategies for children with Wilms tumor (WT) between the European [International Society of Paediatric Oncology (SIOP)] and American [Children's Oncology Group (COG)] study groups, outcomes are very similar, with an overall survival of > 85%. Future strategies aim to de-intensify treatment and reduce toxicity for children with a low risk of relapse and intensify treatment for children with high-risk disease. For metastatic WT, response of lung nodules to chemotherapy is used as a marker to modify treatment intensity. For recurrent WT, a unified approach based on the use of agents that were not used for primary therapy is being introduced. Irinotecan is being explored as a new strategy in both metastatic and relapsed WT. Introduction of biology-driven approaches to risk stratification and new drug treatments has been slower in WT than in some other childhood cancers. While several new biological pathways have been identified recently in WT, their individual rarity has hampered their translation into clinical utility. Identification of robust prognostic factors requires extensive international collaborative studies because of the low proportion who relapse or die. Molecular profiling studies are in progress that should ultimately improve both risk classification and signposting to more targeted therapies for the small group for whom current therapies fail. Accrual of patients with WT to early-phase trials has been low, and the efficacy of these new agents has so far been very disappointing. Better in vitro model systems to test mechanistic dependence are needed so available new agents can be more rationally prioritized for recruitment of children with WT to early-phase trials.

Licoricidin enhances gemcitabine-induced cytotoxicity in osteosarcoma cells by suppressing the Akt and NF-κB signal pathways

Osteosarcoma (OS) is the most common bone malignancy in children and adolescents. Combined treatments of anti-cancer drugs can remarkably improve chemotherapeutic outcomes. Gemcitabine and licoricidin both have potential anti-tumor activity in several cancers. However, the combined therapeutic efficiency of gemcitabine and licoricidin for OS has not been explored. Here, we found that licoricidin or gemcitabine inhibited OS cell viability in a dose-dependent manner. Cotreatment with licoricidin and gemcitabine enhanced gemcitabine-induced cytotoxicity in OS cells. Licoricidin suppressed activation of the Akt and nuclear factor-kappa B (NF-κB) pathways. Gemcitabine had no effect on Akt signal, but facilitated the activation of NF-κB signal in OS cells. Moreover, combined treatment of licoricidin and gemcitabine markedly curbed the activation of Akt and NF-κB pathways in OS cells. Inhibition of the Akt and NF-κB pathways enhanced gemcitabine-induced cytotoxicity in OS cells. In vivo assay further manifested that licoricidin enhanced gemcitabine-induced cytotoxicity in tumor xenograft models of OS via inactivation of the Akt and NF-κB pathways. In conclusion, licoricidin enhanced gemcitabine-induced cytotoxicity in OS cells by inactivation of the Akt and NF-κB pathways in vitro and in vivo.

Redox active metals and H2O2 mediate the increased efficacy of pharmacological ascorbate in combination with gemcitabine or radiation in pre-clinical sarcoma models

Soft tissue sarcomas are a histologically heterogeneous group of rare mesenchymal cancers for which treatment options leading to increased overall survival have not improved in over two decades. The current study shows that pharmacological ascorbate (systemic high dose vitamin C achieving ≥ 20 mM plasma levels) is a potentially efficacious and easily integrable addition to current standard of care treatment strategies in preclinical models of fibrosarcoma and liposarcoma both in vitro and in vivo. Furthermore, enhanced ascorbate-mediated toxicity and DNA damage in these sarcoma models were found to be dependent upon H₂O₂ and intracellular labile iron. Together, these data support the hypothesis that pharmacological ascorbate may represent an easily implementable and non-toxic addition to conventional sarcoma therapies based on taking advantage of fundamental differences in cancer cell oxidative metabolism.

•

Ascorbate sensitizes sarcoma cells to radiation- or chemo-therapy by a mechanism involving redox active metal ions and H₂O₂.

•

Pharmacological ascorbate in combination with radio-chemo-therapy decreases sarcoma disease burden in murine xenografts.

•

Ascorbate-mediated DNA damage is dependent on intracellular redox active iron.

A phase I/II study of gemcitabine during radiotherapy in children with newly diagnosed diffuse intrinsic pontine glioma

The purpose of this phase I/II, open-label, single-arm trial is to investigate the safety, tolerability, maximum tolerated dose and preliminary efficacy of the potential radiosensitizer gemcitabine, administered concomitantly to radiotherapy, in children with newly diagnosed diffuse intrinsic pontine glioma (DIPG). Six doses of weekly gemcitabine were administered intravenously, concomitantly to 6 weeks of hyperfractionated radiotherapy. Successive cohorts received increasing doses of 140, 175 and 200 mg/m² gemcitabine, respectively, following a 3 + 3 dose-escalation schedule without expansion cohort. Dose-limiting toxicities (DLT) were monitored during treatment period. Clinical response was assessed using predefined case report forms and radiological response was assessed using the modified RANO criteria. Quality of life (QoL) was assessed using PedsQL questionnaires. Between June 2012 and December 2016, nine patients were enrolled. Treatment was well tolerated, and no DLTs were observed up to the maximum dose of 200 mg/m². All patients experienced reduction of tumor-related symptoms. QoL tended to improve during treatment. PFS and MOS were 4.8 months (95% CI 4.0–5.7) and 8.7 months (95% CI 7.0–10.4). Classifying patients according to the recently developed DIPG survival prediction model, intermediate risk patients (n = 4), showed a PFS and MOS of 6.4 and 12.4 months, respectively, versus a PFS and MOS of 4.5 and 8.1 months, respectively, in high risk patient (n = 5). Gemcitabine up to 200 mg/m²/once weekly, added to radiotherapy, is safe and well tolerated in children with newly diagnosed DIPG. PFS and MOS were not significantly different from literature.

Phase I and Phase II Objective Response Rates are Correlated in Pediatric Cancer Trials: An Argument for Better Clinical Trial Efficiency

Although many phase I trials report tumor response, formal analysis of efficacy is deferred to phase II. We reviewed paired phase I and II pediatric oncology trials to ascertain the relationship between phase I and II objective response rate (OR%). Single-agent phase I trials were paired with corresponding phase II trials (comparable study drug, dosing schedule, and population). Phase I trials without efficacy data or a matching phase II trial were excluded. OR% was tabulated for all trials, and phase II authors' subjective conclusions regarding efficacy were documented; 35 pairs of trials were analyzed. The correlation between phase I and II OR% was 0.93. Between phase II studies with a "positive" conclusion versus a "negative" one, there was a statistically significant difference in mean phase I OR% (32.0% vs. 4.5%, P<0.001). Thirteen phase II studies were undertaken despite phase I OR% of 0%; only 1 had a "positive" conclusion, and none exceeded OR% of 15%. OR% are highly correlated between phase I and II pediatric oncology trials. Although not a formal measure of drug efficacy, phase I OR% may provide an estimate of phase II response, inform phase II study design, and should be given greater consideration.

Using canine osteosarcoma as a model to assess efficacy of novel therapies: can old dogs teach us new tricks?

Since its domestication more than 10,000 years ago, the dog has been the animal that most intimately shares our work and homelife. Interestingly, the dog also shares many of our diseases including cancer such as osteosarcoma. Like the human, osteosarcoma is the most common bone malignancy of the dog and death from pulmonary metastasis is the most common outcome. The incidence of this spontaneous bone neoplasm occurs ten times more frequently that it does so in children with about 8,000-10,000 cases estimated to occur in dogs in the USA. Because there is no "standard of care" in veterinary medicine, the dog can also serve us by being a model for this disease in children. Although the most common therapy for the dog with osteosarcoma is amputation followed by chemotherapy, not all owners choose this route. Consequently, novel therapeutic interventions can be attempted in the dog with or without chemotherapy that could not be done in humans with osteosarcoma due to ethical concerns. This chapter will focus on the novel therapies in the dog that have been reported or are in veterinary clinical trials at the author's institution. It is hoped that collaboration between veterinary oncologists and pediatric oncologists will lead to the development of novel therapies for (micro- or macro-) metastatic osteosarcoma that improve survival and might ultimately lead to a cure in both species.

Personalizing colon cancer therapeutics: targeting old and new mechanisms of action

The use of pharmaceuticals for colon cancer treatment has been increasingly personalized, in part due to the development of new molecular tools. In this review, we discuss the old and new colon cancer chemotherapeutics, and the parameters that have been shown to be predictive of efficacy and safety of these chemotherapeutics. In addition, we discuss how alternate pharmaceuticals have been developed in light of a potential lack of response or resistance to a particular chemotherapeutic.

What is new in rhabdomyosarcoma management in children?

Optimal management of rhabdomyosarcoma requires establishing the correct pathologic diagnosis, histologic sub-type, primary site, extent of disease (Stage), and extent of resection (Group). Based on these features, cooperative groups in North America and Europe have defined risk-adapted treatments that include surgery, chemotherapy, and usually radiotherapy. This article focuses on recent findings that can impact or have already impacted rhabdomyosarcoma treatment guidelines and highlights controversies that should be addressed in order to improve outcome for children with rhabdomyosarcoma. Rhabdomyosarcoma is currently sub-classified in children based on histology into the favorable embryonal/botryoid/spindle cell types and the unfavorable alveolar form. Risk group assignment depends in part on histologic sub-type. Alveolar rhabdomyosarcoma is sometimes associated with chromosomal translocations, which impact clinical behavior. An important ongoing debate is whether molecular diagnostic tools to identify chromosomal translocations and/or define gene expression profiles should be used to sub-classify rhabdomyosarcoma rather than histology. Clinical trials continue to evaluate retrospective as well as prospective cohorts in order to carefully determine the impact of histology versus biologic features on outcome in the context of specific therapeutic regimens. Most rhabdomyosarcoma recurrences involve the primary site or adjacent region. Cooperative groups continue to investigate new approaches to local control in order to reduce local recurrences and sequelae associated with local therapy. Delaying primary resection until after chemotherapy has started appears to increase the number of tumors that can be completely resected with acceptable morbidity in some primary sites. Radiation dose reductions following delayed primary resection have been investigated. Although outcomes appear similar to the conventional approach of full-dose radiotherapy without delayed primary resection, long-term effects of the two approaches have not been rigorously compared. Early evidence suggests that newer methods of delivering radiotherapy, including intensity-modulated radiotherapy (IMRT), proton beam radiotherapy, and brachytherapy maintain efficacy but may reduce long-term sequelae compared with 3-dimensional conformal radiotherapy. Chemotherapy regimens defined by the cooperative groups vary by risk group. The most commonly used regimens include vincristine and dactinomycin in combination with an alkylating agent, either cyclophosphamide or ifosfamide. In order to improve outcomes, recent clinical trials have introduced new chemotherapeutic agents (e.g. topotecan, carboplatin, or epirubicin) into the treatment regimens. However, outcomes have not been significantly impacted. Novel chemotherapy administration schedules have been tested in patients with metastatic rhabdomyosarcoma, including interval compressed dosing or maintenance therapy, and may be promising. Molecularly targeted agents are currently under investigation in combination with chemotherapy for patients with recurrent or metastatic rhabdomyosarcoma. It is hoped that these novel agents will benefit all patients with rhabdomyosarcoma in the future.

Combination therapy targeting the Chk1 and Wee1 kinases shows therapeutic efficacy in neuroblastoma

Neuroblastoma is uniquely sensitive to single-agent inhibition of the DNA damage checkpoint kinase Chk1, leading us to examine downstream effectors of this pathway and identify mitotic regulator Wee1 as an additional therapeutic target in this disease. Wee1 was overexpressed in both neuroblastoma cell lines and high-risk patient tumors. Genetic or pharmacologic abrogation of Wee1 signaling results in marked cytotoxicity in 10 of 11 neuroblastoma cell lines with a median IC(50) of 300 nmol/L for the Wee1-selective small-molecule inhibitor MK-1775. Murine tumor lines derived from mice that were either heterozygous or homozygous for MycN were particularly sensitive to single-agent inhibition of Wee1 (IC(50)s of 160 and 62 nmol/L, respectively). Simultaneous pharmacologic inhibition of Chk1 and Wee1 acted in a synergistic fashion to further impede neuroblastoma cell growth in vitro, in a manner greater than the individual inhibitors either alone or combined with chemotherapy. Combination Chk1 and Wee1 inhibition also revealed in vivo efficacy in neuroblastoma xenografts. Taken together, our results show that neuroblastoma cells depend on Wee1 activity for growth and that inhibition of this kinase may serve as a therapeutic for patients with neuroblastoma.

Gemcitabine, docetaxel, and bevacizumab in relapsed and refractory pediatric sarcomas

BACKGROUND

The outcome for patients with relapsed and refractory pediatric sarcomas remains dismal. Novel agents are needed to improve overall survival in these patients.

OBSERVATIONS

We present 3 patients with relapsed/refractory sarcomas treated with gemcitabine, docetaxel, and bevacizumab in 3-week cycles. The combination was well tolerated with minimal toxicity. Two patients had a partial response and the third patient had stable disease for >6 months.

CONCLUSIONS

These results are limited by small patient numbers but this strategy should be evaluated in prospective clinical trials.

Randomization and statistical power: paramount in trial reproducibility (even for rare cancers)

This article comments on the importance of randomization and statistical power in clinical trials.

Synergistic interaction between cisplatin and gemcitabine in neuroblastoma cell lines and multicellular tumor spheroids

The efficacy and mechanism of action of cisplatin and gemcitabine were investigated in a panel of neuroblastoma cell lines and multicellular tumor spheroids. In neuroblastoma spheroids, the combination of cisplatin and gemcitabine induced a complete cytostasis at clinical relevant concentrations. A synergistic effect was observed when cells were coincubated with both drugs or preincubated with gemcitabine first. These administration sequences resulted in NASS cells in decreased ERCC1 and XPA expression, two key proteins of the NER DNA repair system, and increased platinum adduct formation in DNA. Most of these phenomena were not observed in SJNB8 cells which might explain the lack of synergy between cisplatin and gemcitabine in SJNB8 cells. Our results showed favorable interactions between cisplatin and gemcitabine in 4 out of 5 cell lines. Therefore, we feel that inclusion of gemcitabine into cisplatin-containing regiments might be a promising new strategy for the treatment of neuroblastoma.

Oxaliplatin, irinotecan, and gemcitabine: a novel combination in the therapy of progressed, relapsed, or refractory tumors in children

Therapeutic options for unresectable neuroendocrine carcinomas and relapsed or refractory solid tumors are still limited in pediatric patients. We present a retrospective review of 12 children (3 to 16 y) in a case series treated with a novel combination of oxaliplatin, irinotecan, and gemcitabine (triple therapy). We defined its feasibility in a mainly outpatient setting and assessed its toxicity and effectiveness. Three patients with unresectable neuroendocrine carcinomas received triple therapy as first-line treatment; 9 children with relapsed or refractory solid tumors of different entities were assigned after failure of standard treatment protocols. The treatment schedule comprised oxaliplatin (85 mg/m²), irinotecan (175 mg/m²), and gemcitabine (1,000 mg/m²), the latter to be repeated on day 8. A median of 7 cycles was applied. Nine of 12 patients showed hematotoxicity 0-III degrees. Gastrointestinal toxicity I-II degrees were handled satisfactorily by supportive drugs. Tumor response was defined as partial response in 1 of 12 children, stable disease in 8 of 12 children, and progressive disease in 3 of 12 children with a median time of disease control of 7 months. We regard triple therapy as a well-tolerated outpatient treatment option offering children a high quality of life and showing considerable effectiveness in delaying tumor progress.

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.

Integrating pharmacogenetics into gemcitabine dosing--time for a change?

Increasing the efficacy of anticancer agents and avoiding toxic effects is a critical issue in clinical oncology. Identifying biomarkers that predict clinical outcome would ensure improved patient care. Gemcitabine is widely used to treat various solid tumors as a single agent or in combination with other drugs. The therapeutic index of gemcitabine is narrow, and abnormal pharmacokinetics leading to changes in plasma exposure is a major cause of adverse effects. A number of biomarkers have been proposed to predict efficacy of gemcitabine, focusing on molecular determinants of response identified at the tumor level. Genetic and functional deregulations that affect the disposition of a drug could be the reason for life-threatening adverse effects or treatment failure. In particular, deregulation of cytidine deaminase, the enzyme responsible for detoxification of most nucleotide analogs, should be examined. Identifying and validating biomarkers for pharmacogenetic testing before administration of gemcitabine is a step towards personalized medicine.

Aerosol gemcitabine: preclinical safety and in vivo antitumor activity in osteosarcoma-bearing dogs

BACKGROUND

Osteosarcoma is the most common skeletal malignancy in the dog and in young humans. Although chemotherapy improves survival time, death continues to be attributed to metastases. Aerosol delivery can provide a strategy with which to improve the lung drug delivery while reducing systemic toxicity. The purpose of this study is to assess the safety of a regional aerosol approach to chemotherapy delivery in osteosarcoma-bearing dogs, and second, to evaluate the effect of gemcitabine on Fas expression in the pulmonary metastasis.

METHODS

We examined the systemic and local effects of aerosol gemcitabine on lung and pulmonary metastasis in this relevant large-animal tumor model using serial laboratory and arterial blood gas analysis and histopathology and immunohistochemistry, respectively.

RESULTS AND CONCLUSIONS

Six hundred seventy-two 1-h doses of aerosol gemcitabine were delivered. The treatment was well tolerated by these subjects with osteosarcoma (n = 20). Aerosol-treated subjects had metastatic foci that demonstrated extensive, predominately central, intratumoral necrosis. Fas expression was decreased in pulmonary metastases compared to the primary tumor (p = 0.008). After aerosol gemcitabine Fas expression in the metastatic foci was increased compared to lung metastases before treatment (p = 0.0075), and even was higher than the primary tumor (p = 0.025). Increased apoptosis (TUNEL) staining was also detected in aerosol gemcitabine treated metastasis compared to untreated controls (p = 0.028). The results from this pivotal translational study support the concept that aerosol gemcitabine may be useful against pulmonary metastases of osteosarcoma. Additional studies that evaluate the aerosol route of administration of gemcitabine in humans should be safe and are warranted.

Phase II study of gemcitabine combined with oxaliplatin in relapsed or refractory paediatric solid malignancies: An innovative therapy for children with Cancer European Consortium Study

AIM

To assess objective response rates after 4 cycles of gemcitabine in combination with oxaliplatin in children and adolescents with relapsed or refractory solid tumours.

METHODS

This multicentre, non-randomised Phase II study included five strata: neuroblastoma, osteosarcoma, medulloblastoma and other CNS tumours strata with two-stage Simon designs and a miscellaneous, extra-cranial solid tumour stratum with descriptive design. Eligibility criteria included: age 6 months to 21 years; measurable, relapsed or refractory solid malignancy; no more than one previous salvage therapy. Gemcitabine was administered intravenously at 1000 mg/m(2) over 100 min followed by oxaliplatin at 100mg/m(2) over 120 min on Day 1 of a 14-d cycle. Tumour response was assessed every 4 cycles according to WHO criteria.

RESULTS

Ninety-three out of 95 patients enrolled in 25 centres received treatment: 12 neuroblastoma; 12 osteosarcoma; 14 medulloblastoma; 13 other CNS tumours and 42 miscellaneous non-CNS solid tumours. Median age was 11.7 years (range, 1.3-20.8 years). Tumour control (CR+PR+SD) at 4 cycles was obtained in 30/93 evaluable patients (32.3%; 95% confidence interval (CI), 22.9-42.7%), including four PR: 1/12 patients with osteosarcoma, 1/12 with medulloblastoma, 1/12 with rhabdomyosarcoma and 1/4 with other sarcoma. Five out of 12 eligible patients with neuroblastoma experienced stable disease. During a total of 481 treatment cycles (median 4, range 1-24 per patient), the most common treatment-related toxicities were haematologic (leukopenia, neutropenia, thrombocytopenia) and neurological (dysesthesia, paresthesia).

CONCLUDING STATEMENT

The gemcitabine-oxaliplatin combination administered in a bi-weekly schedule has acceptable safety profile with limited activity in children with relapsed or refractory solid tumours.

Enhanced anticancer effect of gemcitabine by genistein in osteosarcoma: the role of Akt and nuclear factor-kappaB

Genistein, a nontoxic flavonoid compound, has potent antitumor activity in various cancer cell lines. This study was designed to investigate whether combination therapy with gemcitabine and genistein enhances antitumor efficacy in osteosarcoma cell lines (MG-63 and U2OS). Our results show that significant reduction in cell viability and corresponding induction of apoptosis were observed with combination treatment in both cell lines. On the molecular level, we found that gemcitabine alone can activate nuclear factor kappaB (NF-kappaB) in osteosarcoma, suggesting the potential mechanism of acquired chemoresistance. In contrast, genistein reversed the cancer's resistance to gemcitabine through the downregulation of NF-kappaB activity and the suppression of Akt. These findings suggest that the combination of gemcitabine and genistein enhanced the antitumor efficacy by abrogating the Akt/NF-kappaB pathway. The marked ability to induce apoptosis with a combination of gemcitabine and genistein suggests that this could be a rational and novel approach for osteosarcoma preclinical and clinical trials.

Phase II study of intermediate-dose cytarabine in patients with relapsed or refractory Ewing sarcoma: a report from the Children's Oncology Group

BACKGROUND

Patients with relapsed or refractory Ewing sarcoma have a poor outcome with conventional therapies. Cytarabine decreases EWS/FLI1 protein levels in Ewing sarcoma cells and has demonstrated preclinical activity against Ewing sarcoma in vitro and in vivo. The purpose of this phase II clinical trial was to estimate the response rate of intermediate-dose cytarabine in patients with relapsed or refractory Ewing sarcoma.

PROCEDURE

Patients with a histologic diagnosis of Ewing sarcoma were eligible if they were <30 years of age, had relapsed or refractory measurable disease, and met standard organ function requirements. Patients received cytarabine 500 mg/m(2)/dose intravenously over 2 hr every 12 hr for 10 doses with cycles repeated every 21 days. Response was assessed according to RECIST criteria.

RESULTS

Ten patients (median age 20 years; 7 males) were treated. Only five patients had documented EWS/FLI1 translocated tumors. No objective responses were seen. One patient had stable disease for 5 cycles before developing progressive disease. All patients evaluable for hematologic toxicity developed grade 4 neutropenia and thrombocytopenia during protocol therapy. Patients were not able to receive therapy according to the planned 21-day cycles, with a median interval of 26.5 days.

CONCLUSIONS

Cytarabine at the dose and schedule utilized in this trial resulted in hematologic toxicity that limited delivery of this therapy. This regimen also had minimal activity in this patient population.

Gemcitabine and docetaxel in metastatic sarcoma: past, present, and future

Objective. In the era of oral molecular kinase inhibitors, cytotoxic chemotherapy agents are somewhat overlooked, but remain the backbone of treatment for most cancers. Patients with non-gastrointestinal stromal tumor sarcomas, such as leiomyosarcoma, liposarcoma, and undifferentiated high-grade pleomorphic sarcoma (formerly called malignant fibrous histiocytoma), have received doxorubicin and ifosfamide as the backbone of their treatment for over 15 years or more. The goal of this article is to review the data that have led to the use of gemcitabine and docetaxel as a useful combination for patients with metastatic sarcomas, and to comment on possible synergy of the combination. Methods and results. The literature regarding the use of gemcitabine, docetaxel, or both, is reviewed, with emphasis on patients with metastatic sarcoma. Results. Activity of gemcitabine and docetaxel is observed in leiomyosarcoma and undifferentiated high-grade pleomorphic sarcoma. There is apparent schedule dependence of the combination in other cancers; it is unclear if schedule matters in patients with sarcomas. The dose and schedule of gemcitabine and docetaxel examined in phase II studies are probably too high for routine practice. Conclusions. The combination of gemcitabine and docetaxel is an effective option for patients with metastatic sarcoma, increasing the armamentarium for the practicing oncologist in treating this heterogeneous group of diseases. Given the low response rate to docetaxel as a single agent, it is likely that there is true clinical synergy of the combination. Disclosure of potential conflicts of interest is found at the end of this article.

Implementing Good Clinical Practice in Two Noncommercial Phase II Studies in Children with Cancer

BACKGROUND

In noncommercial clinical drug research the implementation of the principles of Good Clinical Practice (GCP) has been criticized for introducing unnecessary bureaucracy at the expense of scientific activity, especially when small populations such as children or patients with orphan diseases are concerned.

PATIENTS AND METHODS

From May 2003 to September 2005, we conducted two prospective open-label multicenter phase II studies in pediatric oncology. Aside from medical questions, these studies set out to explore the requirements according to the essential standards of the ICH-GCP Guideline in anticipation of the implementation of the EU Regulation in German Drug Law in August 2004; the latter, prospective investigation was initiated by the Coordinating Center for Clinical Trials (KKS).

RESULTS

The main GCP requirements were systematically reviewed and critically discussed by focusing mainly on the situation of noncommercial pediatric drug research.

CONCLUSION

While putting GCP into practice in academic research increases costs, the challenge will be to apply these guidelines to good effect, for better quality and increased evidence.