Randomized phase II window trial of two schedules of irinotecan with vincristine in patients with first relapse or progression of rhabdomyosarcoma: a report from the Children's Oncology Group

Roadmap for the next generation of Children's Oncology Group rhabdomyosarcoma trials

Clinical trials conducted by the Intergroup Rhabdomyosarcoma (RMS) Study Group and the Children's Oncology Group have been pivotal to establishing current standards for diagnosis and therapy for RMS. Recent advancements in understanding the biology and clinical behavior of RMS have led to more nuanced approaches to diagnosis, risk stratification, and treatment. The complexities introduced by these advancements, coupled with the rarity of RMS, pose challenges to conducting large-scale phase 3 clinical trials to evaluate new treatment strategies for RMS. Given these challenges, systematic planning of future clinical trials in RMS is paramount to address pertinent questions regarding the therapeutic efficacy of drugs, biomarkers of response, treatment-related toxicity, and patient quality of life. Herein, the authors outline the proposed strategic approach of the Children's Oncology Group Soft Tissue Sarcoma Committee to the next generation of RMS clinical trials, focusing on five themes: improved novel agent identification and preclinical to clinical translation, more efficient trial development and implementation, expanded opportunities for knowledge generation during trials, therapeutic toxicity reduction and quality of life, and patient engagement.

Single cell transcriptomic profiling identifies tumor-acquired and therapy-resistant cell states in pediatric rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a pediatric tumor that resembles undifferentiated muscle cells; yet the extent to which cell state heterogeneity is shared with human development has not been described. Using single-cell/nucleus RNA sequencing from patient tumors, patient-derived xenografts, primary in vitro cultures, and cell lines, we identify four dominant muscle-lineage cell states: progenitor, proliferative, differentiated, and ground cells. We stratify these RMS cells/nuclei along the continuum of human muscle development and show that they share expression patterns with fetal/embryonal myogenic precursors rather than postnatal satellite cells. Fusion-negative RMS (FN-RMS) have a discrete stem cell hierarchy that recapitulates fetal muscle development and contain therapy-resistant FN-RMS progenitors that share transcriptomic similarity with bipotent skeletal mesenchymal cells. Fusion-positive RMS have tumor-acquired cells states, including a neuronal cell state, that are not found in myogenic development. This work identifies previously underappreciated cell state heterogeneity including unique treatment-resistant and tumor-acquired cell states that differ across RMS subtypes.

Event-free survival in relapsed and refractory rhabdomyosarcoma treated on cooperative group phase II trials: A report from the Children's Oncology Group

BACKGROUND

Novel therapies are needed for relapsed and refractory rhabdomyosarcoma (RRMS). Phase II clinical trials in RRMS have typically utilized radiologic response as the primary activity endpoint, an approach that poses several limitations in RRMS. In this analysis, we aimed to estimate an event-free survival (EFS) endpoint for RRMS that could be used as a benchmark for future studies.

PROCEDURE

We performed a retrospective study of patients with RRMS enrolling on 13 single-agent phase II Children's Oncology Group and legacy group trials from 1997 to 2016. All included trials used radiographic response as their primary activity endpoint. Six-month EFS was estimated from time of trial enrollment with 95% confidence intervals. Clinical characteristics, including trial of enrollment, sex, age, race, histology, number of prior chemotherapies, and radiographic response were evaluated for their impact on 6-month EFS.

RESULTS

We identified 175 patients across 13 trials. The 6-month EFS was 16.8% (11.6%-22.8%). No differences were seen in 6-month EFS based on age, sex, race, or histology. There were nonsignificant trends toward improved 6-month EFS for patients with less than or equal to two prior lines of therapy versus higher than two, for patients enrolled on trials that achieved their primary radiographic response endpoint versus trials that did not, and for patients who achieved complete or partial response compared to those achieving stable disease.

CONCLUSIONS

The prognosis of RRMS enrolled on single-agent phase II trials is poor. This pooled 6-month EFS of RRMS on single-agent trials may be used as a RRMS-specific benchmark for future single-agent phase II trials.

Frontline and Relapsed Rhabdomyosarcoma (FAR-RMS) Clinical Trial: A Report from the European Paediatric Soft Tissue Sarcoma Study Group (EpSSG)

The Frontline and Relapsed Rhabdomyosarcoma (FaR-RMS) clinical trial is an overarching, multinational study for children and adults with rhabdomyosarcoma (RMS). The trial, developed by the European Soft Tissue Sarcoma Study Group (EpSSG), incorporates multiple different research questions within a multistage design with a focus on (i) novel regimens for poor prognostic subgroups, (ii) optimal duration of maintenance chemotherapy, and (iii) optimal use of radiotherapy for local control and widespread metastatic disease. Additional sub-studies focusing on biological risk stratification, use of imaging modalities, including [18F]FDG PET-CT and diffusion-weighted MRI imaging (DWI) as prognostic markers, and impact of therapy on quality of life are described. This paper forms part of a Special Issue on rhabdomyosarcoma and outlines the study background, rationale for randomisations and sub-studies, design, and plans for utilisation and dissemination of results.

The Capacity of Drug-Metabolising Enzymes in Modulating the Therapeutic Efficacy of Drugs to Treat Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a rare soft tissue sarcoma (STS) that predominantly affects children and teenagers. It is the most common STS in children (40%) and accounts for 5-8% of total childhood malignancies. Apart from surgery and radiotherapy in eligible patients, standard chemotherapy is the only therapeutic option clinically available for RMS patients. While survival rates for this childhood cancer have considerably improved over the last few decades for low-risk and intermediate-risk cases, the mortality rate remains exceptionally high in high-risk RMS patients with recurrent and/or metastatic disease. The intensification of chemotherapeutic protocols in advanced-stage RMS has historically induced aggravated toxicity with only very modest therapeutic gain. In this review, we critically analyse what has been achieved so far in RMS therapy and provide insight into how a diverse group of drug-metabolising enzymes (DMEs) possess the capacity to modify the clinical efficacy of chemotherapy. We provide suggestions for new therapeutic strategies that exploit the presence of DMEs for prodrug activation, targeted chemotherapy that does not rely on DMEs, and RMS-molecular-subtype-targeted therapies that have the potential to enter clinical evaluation.

Current Role of Topoisomerase I Inhibitors for the Treatment of Mesenchymal Malignancies and Their Potential Future Use as Payload of Sarcoma-Specific Antibody-Drug Conjugates

BACKGROUND

Topoisomerase I is an enzyme that plays a crucial part in DNA replication and transcription by the relaxation of supercoiled double-stranded DNA. Topoisomerase I inhibitors bind to the topoisomerase I cleavage complex, thereby stabilizing it and preventing the religation of the DNA strands, leading to DNA damage, cell cycle arrest, and apoptosis. Various topoisomerase I inhibitors have been evaluated in solid tumors, and irinotecan and topotecan have been approved for the treatment of epithelial malignancies. None of them have been approved for sarcoma, a diverse group of rare solid tumors with an unmet need for effective treatments.

SUMMARY

Topoisomerase I inhibitors have been evaluated in preclinical studies as single agents or in combination in solid tumors, some of which have included sarcomas where activity was observed. Clinical trials evaluating topoisomerase I inhibitors for the treatment of sarcoma have shown limited efficacy as monotherapy. In combination with other cytotoxic agents, topoisomerase I inhibitors have become part of clinical routine in selected sarcoma subtypes. Regimens such as irinotecan/vincristine/temozolomide are used in relapsed rhabdomyosarcoma, irinotecan/temozolomide and vincristine/topotecan/cyclophosphamide are commonly given in refractory Ewing sarcoma, and topotecan/carboplatin showed some activity in advanced soft tissue sarcoma. This review provides an overview of key studies with topoisomerase I inhibitors for the treatment of sarcoma. Topoisomerase I inhibitors are currently also being assessed as "payloads" for antibody-drug conjugates (ADCs), allowing for the targeting of specific antigen-expressing tumor cells and the delivery of the inhibitor directly to the tumor cells with the potential of enhancing therapeutic efficacy while minimizing systemic toxicity. Here, we also provide a brief overview on topoisomerase I-ADCs.

KEY MESSAGE

Topoisomerase I inhibitors are an important component of some systemic therapies for selected sarcomas and have potent cytotoxic properties and pharmacological characteristics that make them relevant candidates as payloads for the development of sarcoma-specific ADCs. ADCs are antibody-based targeted agents allowing for efficient and specific delivery of a given drug to the tumor cell. Topoisomerase I-ADCs are a novel targeted delivery approach which may have the potential to improve the therapeutic index of topoisomerase I inhibitors in the treatment of sarcoma and warrants investigation in a broad variety of mesenchymal malignancies.

Common queries in managing rhabdomyosarcoma in low- and middle-income countries: An Indo-North American collaboration

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma among children and adolescents. The management of RMS involves risk stratification of the patients based on various clinicopathological characteristics. The multimodality treatment approach requires chemotherapy, surgery, and/or radiation. The treatment of RMS necessitates the involvement of multiple disciplines, such as pathology, pediatric oncology, surgery, and radiation oncology. The disease heterogeneity, molecular testing, evolving treatment regimens, and limited resources are some of the challenges faced by clinicians while treating a patient with RMS in low- and middle-income countries (LMICs). In this review, we endeavor to bring experts from varying fields to address clinicians' common questions while managing a child or adolescent with RMS in LMICs. This review is most applicable to level 2 centers in LMICs as per the levels of services described by the Adapted Treatment Regimens Working Group of the Pediatric Oncology in Developing Countries committee of the International Society of Pediatric Oncology.

Regorafenib plus Vincristine and Irinotecan in Pediatric Patients with Recurrent/Refractory Solid Tumors: An Innovative Therapy for Children with Cancer Study

PURPOSE

This phase Ib study defined the safety, MTD, and recommended phase II dose (RP2D) of regorafenib combined with vincristine and irinotecan (VI). Secondary objectives were evaluation of antitumor activity and pharmacokinetics (PK) of regorafenib and irinotecan.

PATIENTS AND METHODS

Patients aged 6 months to <18 years with relapsed/refractory solid malignancies [≥50% with rhabdomyosarcoma (RMS)] received regorafenib (starting dose 72 mg/m2/day) concomitantly or sequentially with vincristine 1.5 mg/m2 on days 1 and 8, and irinotecan 50 mg/m2 on days 1-5 (21-day cycle). Adverse events (AE) and tumor response were assessed. PK (regorafenib and irinotecan) were evaluated using a population PK model.

RESULTS

We enrolled 21 patients [median age, 10 years; 12, RMS; 5, Ewing sarcoma (EWS)]. The MTD/RP2D of regorafenib in the sequential schedule was 82 mg/m2. The concomitant dosing schedule was discontinued because of dose-limiting toxicities in 2 of 2 patients treated. Most common grade 3/4 (>30% of patients) AEs were neutropenia, anemia, thrombocytopenia, and leukopenia. The overall response rate was 48% and disease control rate [complete response (CR)/partial response/stable disease/non-CR/non-progressive disease] was 86%. Median progression-free survival was 7.0 months [95% confidence interval (CI), 2.9-14.8] and median overall survival was 8.7 months (95% CI, 5.5-16.3). When combined with VI, regorafenib PK was similar to single-agent PK in children and adults (treated with regorafenib 160 mg/day).

CONCLUSIONS

Regorafenib can be combined sequentially with standard dose VI in pediatric patients with relapsed/refractory solid tumors with appropriate dose modifications. Clinical activity was observed in patients with RMS and EWS (ClinicalTrials.gov NCT02085148).

Survival outcomes including salvage therapy of adult head and neck para-meningeal rhabdomyosarcoma: a multicenter retrospective study from Japan

BACKGROUND

Rhabdomyosarcoma is the most common soft tissue sarcoma in children, but rare in adults. Para-meningeal rhabdomyosarcoma in head and neck (PM-HNRMS) is less applicable for surgery due to the anatomic reason. PM-HNRMS has a poor prognosis in children. However, its clinical outcomes remain unclear in adults due to the rarity. Further, there is almost no detailed data about salvage therapy.

METHODS

We retrospectively examined the adult patients with PM-HNRMS treated at institutions belonging to the Kyushu Medical Oncology Group from 2009 to 2022. We evaluated the overall survival (OS) and progression-free survival (PFS) of the patients who received a first-line therapy. We also reviewed the clinical outcomes of patients who progressed against a first-line therapy and received salvage therapy.

RESULTS

Total 11 patients of PM-HNRMS received a first-line therapy. The characteristics were as follows: median age: 38 years (range 25 - 63 years), histology (alveolar/spindle): 10/1, and risk group (intermediate/high): 7/4. As a first-line therapy, VAC and ARST0431-based regimen was performed in 10 and 1 patients, respectively. During a first-line therapy, definitive radiation for all lesions were performed in seven patients. The median PFS was 14.2 months (95%CI: 6.0 - 25.8 months): 17.1 months (95%CI: 6.0 - not reached (NR)) for patients with stage I-III and 8.5 months (95%CI: 5.2 - 25.8 months) for patients with stage IV. The 1-year and 3-year PFS rates were 54.5% and 11.3% for all patients. Median OS in all patients was 40.8 months (95%CI: 12.1 months-NR): 40.8 months (95%CI: 12.1 - NR) for patients with stage I-III and NR for patients with stage IV. The 5-year OS rate was 48.5% for all patients. Among seven patients who received salvage therapy, three are still alive, two of whom remain disease-free for over 4 years after completion of the last therapy. Those two patients received multi-modal therapy including local therapy for all detected lesions.

CONCLUSION

The cure rate of adult PM-HNRMS is low in spite of a first-line therapy in this study. Salvage therapy might prolong the survival in patients who received the multi-modal therapy including local therapy for all detected lesions.

Current topics and management of head and neck sarcomas

Given the low incidence, variety of histological types, and heterogeneous biological features of head and neck sarcomas, there is limited high-quality evidence available to head and neck oncologists. For resectable sarcomas, surgical resection followed by radiotherapy is the principle of local treatment, and perioperative chemotherapy is considered for chemotherapy-sensitive sarcomas. They often originate in anatomical border areas such as the skull base and mediastinum, and they require a multidisciplinary treatment approach considering functional and cosmetic impairment. Moreover, head and neck sarcomas may exhibit different behaviour and characteristics than sarcomas of other areas. In recent years, the molecular biological features of sarcomas have been used for the pathological diagnosis and development of novel agents. This review describes the historical background and recent topics that head and neck oncologists should know about this rare tumour from the following five perspectives: (i) epidemiology and general characteristics of head and neck sarcomas; (ii) changes in histopathological diagnosis in the genomic era; (iii) current standard treatment by histological type and clinical questions specific to head and neck; (iv) new drugs for advanced and metastatic soft tissue sarcomas; and (v) proton and carbon ion radiotherapy for head and neck sarcomas.

Pediatric DDR inhibitor combinations: Are WEE1 there yet?

A phase 2 study of the WEE1 inhibitor adavosertib in combination with irinotecan in children demonstrates an intriguing positive signal of efficacy in neuroblastoma, a pediatric tumor characterized by replication stress. Further pediatric development of adavosertib and related compounds targeting DNA damage response will be challenged by appropriate patient selection, fit‐for‐filing trial design, and ongoing access to agents, likely to be predicated on success in adult malignancy.

Alveolar rhabdomyosarcoma has superior response rates to vinorelbine compared to embryonal rhabdomyosarcoma in patients with relapsed/refractory disease: A meta-analysis

BACKGROUND

Patients with alveolar rhabdomyosarcoma (ARMS) have inferior outcomes compared to patients with embryonal rhabdomyosarcoma (ERMS) and more effective chemotherapy options are needed for these patients. Vinorelbine is a semisynthetic vinca alkaloid that has clinical activity in relapsed rhabdomyosarcoma (RMS) when used alone or in combination with cyclophosphamide.

AIMS

The goal of our study was to evaluate whether RMS histology subtype influences response rate to vinorelbine alone or in combination.

MATERIALS & METHODS

Five Phase 2 trials that enrolled RMS patients were included in the meta-analysis. Two studies evaluated vinorelbine alone, two studies evaluated vinorelbine in combination with low dose oral cyclophosphamide, and one study evaluated vinorelbine and intravenous cyclophosphamide in combination with temsirolimus or bevacizumab. All RMS patients had relapsed or refractory disease and had received at least one prior therapy. Response was reported according to RECIST1.1 and was defined as a complete or partial response. Response data was obtained from published results or from trial principal investigator. RMS NOS patients were grouped with ERMS patients for this analysis. Summary estimates comparing differences between ARMS and ERMS response rates were generated using a random-effects model to account for heterogeneity among the studies.

RESULTS

One hundred fifty-six enrolled patients evaluable for response were included in the meta-analysis, 85 ARMS, 64 ERMS and 7 RMS-NOS. The combined effect generated from the random-effects model demonstrated a 41% increase (p = 0.001, 95% CI; 0.21-0.60) in response to vinorelbine as a single agent or in combination in patients with ARMS compared to patients with ERMS. There was no significant difference in the rate of progressive disease between patients with ARMS compared to ERMS (p = 0.1, 95%CI; -0.26-0.02).

DISCUSSION

Vinorelbine is an active agent for the treatment of relapsed or refractory RMS and a meta-analysis of Phase 2 studies shows that radiographic responses in patients with ARMS were significantly higher than ERMS or RMS-NOS.

CONCLUSION

These data support further investigation of vinorelbine in newly diagnosed patients with RMS particularly those with alveolar histology.

Platinum-Based Regimens Are Active in Advanced Pediatric-Type Rhabdomyosarcoma in Adults and Depending on HMGB1 Expression

Rhabdomyosarcoma (RMS) in adults is a rare and aggressive disease, which lacks standard therapies for relapsed or advanced disease. This retrospective study aimed to describe the activity of BOMP-EPI (bleomycin, vincristine, methotrexate and cisplatin alternating with etoposide, cisplatin and ifosfamide), an alternative platinum-based regimen, in adult patients with relapsed/metastatic RMS. In the study, 10 patients with RMS with a median age at diagnosis of 20.8 years and a female/male distribution of 6/4 received a mean of 2.5 cycles of BOMP-EPI. The best RECIST response was a complete response in 1/10 (10%) patients, a partial response in 5/10 (50%), stable disease in 3/10 (30%) and progression in 1/10 (10%). With a median follow-up in the alive patients from the start of therapy of 30.5 months (15.7-258), all patients progressed with a median progression-free survival of 8.47 months (95% CI 8.1-8.8), and 7/10 patients died with a median overall survival of 24.7 months (95% CI 13.7-35.6). BOMP-EPI was an active chemotherapy regimen in adults with pediatric-type metastatic RMS, with outcomes in terms of survival that seem superior to what was expected for this poor-prognosis population. Low HMGB1 expression level was identified as a predictive factor of better response to this treatment.

Irinotecan dose schedule for the treatment of Ewing sarcoma

Irinotecan and temozolomide achieve objective responses in patients with Ewing sarcoma that recurs after initial therapy. Optimal dose schedules have not been defined. We reviewed published series of patients treated with irinotecan and temozolomide for Ewing sarcoma that recurred after initial therapy. We compared objective response rates for patients who received 5-day irinotecan treatment schedules to response rates for patients who achieved 10-day irinotecan treatment schedules. Among 89 patients treated with a 10-day irinotecan schedule, there were 47 objective responses (53%). Among 180 patients treated with a 5-day irinotecan schedule, there were 52 responses (29%). In the treatment of recurrent Ewing sarcoma, investigators should consider the use of a 10-day schedule for administration of irinotecan.

Use of Porcine Urinary Bladder Matrix in Socket Reconstruction After Pediatric Orbital Exenteration

Reconstruction options after orbital exenteration can be challenging, time-consuming, and require intensive postoperative care. Engineered dermal acellular matrices offer a quick and easy option for wound healing that has proven to be successful in various settings. Specifically, the porcine urinary bladder matrix has demonstrated success in periocular and orbital wound healing. This report describes a pediatric patient who underwent repair with porcine urinary bladder matrix after orbital exenteration for recurrent alveolar rhabdomyosarcoma. The patient did not require any additional reconstructive procedures. To our knowledge, this is the youngest patient to receive a porcine urinary bladder matrix after exenteration.

Economic Evaluation of a Tumour-Agnostic Therapy: Dutch Economic Value of Larotrectinib in TRK Fusion-Positive Cancers

BACKGROUND

Larotrectinib is the first tumour-agnostic therapy that has been approved by the European Medicines Agency. Tumour-agnostic therapies are indicated for a multitude of tumour types. The economic models supporting reimbursement submissions of tumour-agnostic therapies are complex because of the multitude of indications per model.

OBJECTIVE

The objective of this paper was to evaluate the cost effectiveness of larotrectinib compared with standard of care in patients with cancer with tropomyosin receptor kinase fusion-positive tumour types in the Netherlands.

METHODS

A previously constructed cost-effectiveness model with a partitioned survival approach was adapted to the Dutch setting, simulating costs and effects of treatment in patients with tropomyosin receptor kinase fusion-positive cancer. The cost-effectiveness model conducts a naïve comparison of larotrectinib to a weighted comparator standard-of-care arm. Dutch specific resource use and costs were implemented and inflated to reflect 2019 euros. The analysis includes a lifetime horizon and a societal perspective.

RESULTS

Larotrectinib versus Dutch standard of care resulted in 5.61 incremental (QALYs) and €232,260 incremental costs, leading to an incremental cost-effectivenes ratio of €41,424/QALY. The probabilistic sensitivity analysis reveals a 88% chance of larotrectinib being cost effective compared with the pooled comparator standard-of-care arm at the applicable €80,000/QALY willingness-to-pay threshold in the Netherlands.

CONCLUSIONS

The incremental cost-effectivenes ratio was well below the applicable threshold for diseases with a high burden of disease in the Netherlands (€80,000). At this threshold, larotrectinib was estimated to be a cost-effective treatment for patients with tropomyosin receptor kinase fusion-positive cancer compared with current standard of care in the Netherlands.

Vincristine, Irinotecan, and Temozolomide in Patients With Relapsed/Refractory Neuroblastoma

Purpose

The combination of irinotecan, temozolomide and vincristine has been proposed as an effective salvage regimen for some pediatric malignancies. Thus, we sought to evaluate this combination for patients with relapsed and refractory neuroblastoma (NB).

Patients and Methods

In this retrospective study, forty-six patients with relapsed or refractory NB were treated with the combination of vincristine (1.5 mg/m² i.v. day 1), irinotecan (50 mg/m²/day i.v. days 1–5) and temozolomide (100 mg/m²/day p.o. days 1–5) (VIT) during the period 2011–2019. All toxicities were documented.

Results

A total of 251 cycles (median 6 cycles/patient) were administered. A complete response (CR) was achieved in 5 patients, partial response (PR) in 27 patients, stable disease (SD) in 8 patients, and progression disease (PD) in 6 patients, with an overall objective response rate (CR+PR) of 69.6%. Eighteen patients developed diarrhea with Grade 3 or less. Grade 1-2 hematologic toxicity occurred in 10 patients. Grade 3-4 hematologic toxicity developed in 32 patients. VIT was an effective regimen for different metastatic sites. UGT1A*28 genotyping performed in 7 patients revealed wild type. Diarrhea occurred in 4 of them.

Conclusion

The shorter, 5-day VIT regimen is an active and well-tolerated salvage regimen in relapse/refractory NB.

Rising drug cost impacts on cost-effectiveness of 2 chemotherapy regimens for intermediate-risk rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

The Children's Oncology Group clinical trial for intermediate risk rhabdomyosarcoma randomized participants to a combination of vincristine, dactinomycin, and cyclophosphamide (VAC) alone or VAC alternating with vincristine plus irinotecan (VAC/VI). Clinical outcomes were similar, but toxicity profiles differed. This study estimates the cost differences between arms from the health care system's perspective.

METHODS

A decision-analytic model was used to estimate the incremental cost-effectiveness ratio (ICER) of VAC versus VAC/VI. Protocol-required or recommended medications and laboratory studies were included. Costs were obtained from national databases or supporting literature and inflated to 2019 US dollars. Demographic and outcome data were obtained from the clinical trial and directed chart reviews. Life-years (LY) were estimated from life-expectancy tables and discounted by 3% annually. Probabilistic sensitivity analyses and alternative clinical scenarios identified factors driving costs.

RESULTS

Mean direct medical costs of VAC and VAC/VI were $164,757 and $102,303, respectively. VAC was associated with an additional 0.97 LY and an ICER of $64,386/LY compared with VAC/VI. The ICER was sensitive to survival estimations and to alternative clinical scenarios including outpatient cyclophosphamide delivery (ICER $49,037/LY) or substitution of alternative hematopoietic growth factor schedules (ICER $73,191-$91,579/LY). Applying drug prices from 2012 decreased the total costs of VAC by 20% and VAC/VI by 15% because of changes in dactinomycin and pegfilgrastim prices.

CONCLUSIONS

Neither arm was clearly more cost-effective. Pharmaceutical pricing and location of treatment drove costs and may inform future treatment decisions. Rising pharmaceutical costs added $30,000 per patient, a finding important for future drug-pricing policy decisions.

LAY SUMMARY

Two chemotherapy regimens recently tested side-by-side for rhabdomyosarcoma had similar tumor outcomes, but different side effects. The health care costs of each regimen were compared; neither was clearly more cost-effective. However, the costs of each treatment changed dramatically with choices of supportive medicines and location of treatment. Costs of treatment rose by 15% to 20% because of rising US drug costs not associated with the clinical trial.

An overview of current results with the vincristine-irinotecan-temozolomide combination with or without bevacizumab in pediatric, adolescence and adult solid tumors

Malignant tumors in young patients present a significant therapeutic challenge for physicians, partially due to their rarity and a relative lack of data, at least compared to adult tumors. As a result, there is an urgent need to explore new possible therapeutic regimens, either by introducing novel agents or by exploring combinations of existing agents. Vincristine, Temozolomide and Irinotecan are chemotherapeutic drugs which have emerged over the last six decades as monotherapy or as part of therapeutic regimens in various solid tumors. Combining these agents can yield strong synergistic effects, as suggested by preclinical data and results from clinical trials. Furthermore, adding novel molecules, such as anti-VEGF factor Bevacizumab to the aforementioned regimens, has shown efficacy in a limited number of trials, which are thoroughly analyzed throughout this review. Data presented throughout this paper suggest that VIT(b) regimen should be further explored in solid tumors in pediatric and adolescent patients.

Randomized Phase II Trial of Vincristine-Irinotecan With or Without Temozolomide, in Children and Adults With Relapsed or Refractory Rhabdomyosarcoma: A European Paediatric Soft tissue Sarcoma Study Group and Innovative Therapies for Children With Cancer Trial

PURPOSE

The VIT-0910 trial was conducted to evaluate efficacy and safety of the vincristine-irinotecan combination with and without temozolomide (VIT and VI, respectively) in relapsed or refractory rhabdomyosarcoma (RMS).

METHODS

In this randomized European phase II trial, patients age 0.5-50 years received 21-day cycles combining vincristine (1.5 mg/m² once a day on day 1 and day 8) and irinotecan (50 mg/m² once a day from day 1 to day 5) with and without temozolomide (125 mg/m² once a day from day 1 to day 5 and 150 mg/m² once a day from cycle 2), until progression or unacceptable toxicity. The primary end point was objective response rate after two cycles. Secondary end points included best response, progression-free survival, overall survival, and adverse events. A Simon 2-stage design was initially planned to separately analyze 40 patients/arm. After amendment, the trial sample size was increased to 120 and a comparison between arms, adjusted for confounding factors, was added to the statistical plan (ClinicalTrials.gov, NCT01355445).

RESULTS

Overall, 120 patients (60 per arm) were recruited in 37 European centers. The median age was 11 years (range, 0.75-45); 89% of patients had a relapsed RMS. The objective response rate was 44% (24 of 55 evaluable patients) for VIT versus 31% (18 of 58) for VI (adjusted odds ratio, 0.50; 95% CI, 0.22 to 1.12; P = .09). The VIT arm achieved significantly better overall survival (adjusted hazard ratio, 0.55; 95% CI, 0.35 to 0.84; P = .006) compared with VI, with consistent progression-free survival results (adj-hazard ratio, 0.68; 95% CI, 0.46 to 1.01; P = .059). Overall, patients experienced adverse events ≥ grade 3 more frequently with VIT than VI (98% v 78%, respectively; P = .009), including a significant excess of hematologic toxicity (81% v 61%; P = .025).

CONCLUSION

The addition of temozolomide to VI improved chemotherapy efficacy for patients with relapsed RMS, with manageable increase in toxicity. VIT is considered the new standard treatment in these patients in the European paediatric Soft Tissue Sarcoma Group and will be the control arm in the next randomized trial.

More Than Meets the Eye? A Cautionary Tale of Malignant Ectomesenchymoma Treated as Low-risk Orbital Rhabdomyosarcoma

Malignant ectomesenchymoma (MEM) is a rare multiphenotypic tumor comprised of mesenchymal and neuroectodermal components. MEM is typically diagnosed in infants and younger children and outcomes are variable. The current approach for treating MEM includes targeting the more aggressive mesenchymal component of the tumor, which is often rhabdomyosarcoma. Here, we describe a case of an orbital tumor initially diagnosed and treated as low-risk rhabdomyosarcoma. Local failure prompting a second biopsy revealed neuronal differentiation consistent with a diagnosis of MEM. Intensifying therapy and local radiotherapy led to a long-term cure. This case offers a cautionary tale that while outcomes for MEM were similar to matched rhabdomyosarcoma cohorts when treated on conventional Intergroup Rhabdomyosarcoma Study Group (IRSG) III/IV protocols, treating MEM using a decreased intensity low-risk rhabdomyosarcoma regimen may not be sufficient.

Programmed cell death, redox imbalance, and cancer therapeutics

Cancer cells are disordered by nature and thus featured by higher internal redox level than healthy cells. Redox imbalance could trigger programmed cell death if exceeded a certain threshold, rendering therapeutic strategies relying on redox control a possible cancer management solution. Yet, various programmed cell death events have been consecutively discovered, complicating our understandings on their associations with redox imbalance and clinical implications especially therapeutic design. Thus, it is imperative to understand differences and similarities among programmed cell death events regarding their associations with redox imbalance for improved control over these events in malignant cells as well as appropriate design on therapeutic approaches relying on redox control. This review addresses these issues and concludes by bringing affront cold atmospheric plasma as an emerging redox controller with translational potential in clinics.

Anlotinib, Vincristine, and Irinotecan for Advanced Ewing Sarcoma After Failure of Standard Multimodal Therapy: A Two-Cohort, Phase Ib/II Trial

BACKGROUND

Both protracted irinotecan and antiangiogenesis therapy have shown promising efficacy against Ewing sarcoma (EWS).

METHODS

Patients diagnosed with recurrent or refractory EWS were enrolled and further categorized into cohort A (≥16 years) or cohort B (<16 years). In the dose-defining phase Ib portion, anlotinib was given daily at a fixed dose, while a 3+3 design with dose de-escalation was used to determine the dose of irinotecan. The next dose-expanding phase II portion employed a conventional two-stage study design model. The primary endpoint was objective response rate at 12 weeks (ORR12w ).

RESULTS

A total of 41 patients finally received the treatment regimen, including 29 in cohort A and 12 in cohort B. For cohort A, the first five patients were treated at the initial level of 20 mg/m2 /d d × 5 × 2, and two of them subsequently a dose-limiting toxicity (DLT). An additional six patients were then treated at 15 mg/m2 without any DLT, and the RP2D was determined. Notably, 23 out of 24 patients in cohort A were available for response evaluation at 12 weeks. ORR12w was determined to be 62.5%. For cohort B, no DLT was observed in the first six patients at the initial dose level. At last, 12 patients were included in cohort B. The ORR12w was 83.3%. The most frequently observed grade 3/4 adverse events were leukopenia (28.5%), neutropenia (24.4%), anemia (8.7%), and diarrhea (3.7%).

CONCLUSION

The combination of vincristine, irinotecan, and anlotinib demonstrated an acceptable toxicity profile and promising clinical efficacy in patients with advanced EWS.

IMPLICATIONS FOR PRACTICE

This is the first trial to evaluate an irinotecan-based regimen in combination with antiangiogenesis tyrosine kinase inhibitors in Ewing sarcoma (EWS). A 3+3 design with dose de-escalation was used to determine the most appropriate dose of irinotecan in each cohort. The next dose-expanding phase II portion employed a conventional two-stage study design model. The objective response rate was 62.5% for adults and 83.3% for children. Median overall survival was not matured. This study shows that the combination of vincristine, irinotecan, and anlotinib demonstrates an acceptable toxicity profile and promising clinical efficacy in patients with advanced EWS.

GEIS-SEHOP clinical practice guidelines for the treatment of rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most frequent soft tissue sarcoma (STS) in children and adolescents. In Spain the annual incidence is 4.4 cases per million children < 14 years. It is an uncommon neoplasm in adults, but 40% of RMS are diagnosed in patients over 20 years of age, representing 1% of all STS in this age group. RMS can appear anywhere in the body, with some sites more frequently affected including head and neck, genitourinary system and limbs. Assessment of a patient with suspicion of RMS includes imaging studies (MRI, CT, PET-CT) and biopsy. All patients with RMS should receive chemotherapy, either at diagnosis in advanced or metastatic stages, or after initial resection in early local stages. Local control includes surgery and/or radiotherapy depending on site, stage, histology and response to chemotherapy. This guide provides recommendations for diagnosis, staging and treatment of this neoplasm.

Radiosurgery, reirradiation, and brachytherapy

Radiosurgery and brachytherapy are potentially useful treatment techniques that are sparingly applied in pediatric oncology. They are often used in the setting of reirradiation for recurrent or metastatic tumors. Reirradiation in children with recurrent tumors is complicated by the tolerance of critical organs and the potential risks for overall long-term dose-dependent complications. We review the current literature available in support of reirradiation and the use of radiosurgery and brachytherapy in pediatric patients.

Prioritization of Novel Agents for Patients with Rhabdomyosarcoma: A Report from the Children's Oncology Group (COG) New Agents for Rhabdomyosarcoma Task Force

Rhabdomyosarcoma is the most common soft tissue sarcoma diagnosed in children and adolescents. Patients that are diagnosed with advanced or relapsed disease have exceptionally poor outcomes. The Children’s Oncology Group (COG) convened a rhabdomyosarcoma new agent task force in 2020 to systematically evaluate novel agents for inclusion in phase 2 or phase 3 clinical trials for patients diagnosed with rhabdomyosarcoma, following a similar effort for Ewing sarcoma. The task force was comprised of clinicians and basic scientists who collectively identified new agents for evaluation and prioritization in clinical trial testing. Here, we report the work of the task force including the framework upon which the decisions were rendered and review the top classes of agents that were discussed. Representative agents include poly-ADP-ribose polymerase (PARP) inhibitors in combination with cytotoxic agents, mitogen-activated protein kinase (MEK) inhibitors in combination with type 1 insulin-like growth factor receptor (IGFR1) inhibitors, histone deacetylase (HDAC) inhibitors, and novel cytotoxic agents.

Relapsed Rhabdomyosarcoma

Relapsed rhabdomyosarcoma (RMS) represents a significant therapeutic challenge. Nearly one-third of patients diagnosed with localized RMS and over two-thirds of patients with metastatic RMS will experience disease recurrence following primary treatment, generally within three years. Clinical features at diagnosis, including primary site, tumor invasiveness, size, stage, and histology impact likelihood of relapse and prognosis post-relapse. Aspects of initial treatment, including extent of surgical resection, use of radiotherapy, and chemotherapy regimen, are also associated with post-relapse outcomes, as are features of the relapse itself, including time to relapse and extent of disease involvement. Although there is no standard treatment for patients with relapsed RMS, several general principles, including tissue biopsy confirmation of diagnosis, assessment of post-relapse prognosis, determination of the feasibility of additional local control measures, and discussion of patient goals, should all be part of the approach to care. Patients with features suggestive of a favorable prognosis, which include those with botryoid RMS or stage 1 or group I embryonal RMS (ERMS) who have had no prior treatment with cyclophosphamide, have the highest chance of achieving long-term cure when treated with a multiagent chemotherapy regimen at relapse. Unfortunately, patients who do not meet these criteria represent the majority and have poor outcomes when treated with such regimens. For this group, strong consideration should be given for enrollment on a clinical trial.

Phase 1 trial of olaratumab monotherapy and in combination with chemotherapy in pediatric patients with relapsed/refractory solid and central nervous system tumors

Olaratumab is a monoclonal antibody that specifically binds to platelet-derived growth factor receptor alpha (PDGFRα) and blocks receptor activation. We conducted a phase 1 trial to evaluate the safety of olaratumab and determine a recommended dose in combination with three different chemotherapy regimens in children. Patients <18 years with relapsed/refractory solid or central nervous system tumors were enrolled to two dose levels of olaratumab. Patients received olaratumab monotherapy at 15 mg/kg (Part A) or 20 mg/kg (Part B) on Days 1 and 8 of the first 21-day cycle, followed by olaratumab combined with standard fixed doses of chemotherapy with doxorubicin, vincristine/irinotecan, or high-dose ifosfamide by investigator choice for subsequent 21-day cycles. In Part C, patients received olaratumab 20 mg/kg plus assigned chemotherapy for all cycles. Parts A-C enrolled 68 patients across three chemotherapy treatment arms; olaratumab in combination with doxorubicin (N = 16), vincristine/irinotecan (N = 26), or ifosfamide (N = 26). Three dose-limiting toxicities (DLTs) occurred during olaratumab monotherapy (at 15 mg/kg, grade [G] 4 alanine aminotransferase [ALT]; at 20 mg/kg, G3 lung infection and G3 gamma-glutamyl transferase). One DLT occurred during vincristine/irinotecan with olaratumab 20 mg/kg therapy (G3 ALT). Treatment-emergent adverse events ≥G3 in >25% of patients included neutropenia, anemia, leukopenia, lymphopenia, and thrombocytopenia. Pharmacokinetic profiles of olaratumab with chemotherapy were within the projected range based on adult data. There was one complete response (rhabdomyosarcoma [Part B vincristine/irinotecan arm]) and three partial responses (two rhabdomyosarcoma [Part A doxorubicin arm and Part C doxorubicin arm]; one pineoblastoma [Part B vincristine/irinotecan arm]). Olaratumab was tolerable and safely administered in combination with chemotherapy regimens commonly used in children and adolescents.

Survival outcomes of patients with localized FOXO1 fusion-positive rhabdomyosarcoma treated on recent clinical trials: A report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

BACKGROUND

The objective of this analysis was to evaluate the clinical factors influencing survival outcomes in patients with localized (clinical group I-III), FOXO1 fusion-positive rhabdomyosarcoma (RMS).

METHODS

Patients with confirmed FOXO1 fusion-positive RMS who were enrolled on 3 completed clinical trials for localized RMS were included in the analytic cohort. Outcomes were analyzed using the Kaplan-Meier method to estimate event-free survival (EFS) and overall survival (OS), and the curves were compared using the log-rank test. A Cox proportional hazards regression model was used to perform multivariate analysis of prognostic factors that were significant in the univariate analysis.

RESULTS

The estimated 4-year EFS and OS of 269 patients with localized, FOXO1 fusion-positive RMS was 53% (95% CI, 47%-59%) and 69% (95% CI, 63%-74%), respectively. Univariate analysis revealed that several known favorable clinical characteristics, including age at diagnosis between 1 and 9 years, complete surgical resection, tumor size ≤5 cm, favorable tumor site, absence of lymph node involvement, confinement to the anatomic site of origin, and PAX7-FOXO1 fusion, were associated with improved outcomes. Multivariate analysis identified older age (≥10 years) and large tumor size (>5 cm) as independent, adverse prognostic factors for EFS within this population, and patients who had both adverse features experienced substantially inferior outcomes.

CONCLUSIONS

Patients with localized, FOXO1 fusion-positive RMS can be further risk stratified based on clinical features at diagnosis, and older patients with large primary tumors have the poorest prognosis.

Treatment strategy and long-term outcomes of primary intracranial rhabdomyosarcoma: a single-institution experience and systematic review

OBJECTIVE

Primary intracranial rhabdomyosarcoma (PIRMS) is rare, and the effects of the treatment strategy on overall survival (OS) are unclear. This study aimed to evaluate risk factors pertinent to OS and to propose an optimal treatment strategy.

METHODS

Clinical data of patients with PIRMS treated at Beijing Tiantan Hospital and from the English-language literature between 1946 and 2018 were reviewed. A literature review was performed via Ovid, MEDLINE, Embase, PubMed, Web of Science, and Cochrane databases using the terms "rhabdomyosarcoma," "intracranial," "cerebral," and "brain." Previously published data were processed and used according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

There were 8 males (66.7%) and 4 females with PIRMS at our institution, with a mean age of 24.3 years. Gross-total resection was achieved in 4 patients (33.3%), and adjuvant radiation and chemotherapy were administered in 5 (45.5%) and 3 (27.3%) patients, respectively. After a mean follow-up period of 13.7 months, all patients developed local-regional recurrence and died of the disease. Twenty-nine cases (14 female and 15 male) were reported in the literature with a median age of 9.0 years. After a mean follow-up duration of 18.6 months, 13 patients (44.8%) developed recurrences, 7 patients (24.1%) had extracranial metastasis, and 14 patients (48.3%) died. In the pooled cases, adjuvant radiation (hazard ratio [HR] 0.089, 95% confidence interval [CI] 0.027-0.288, p < 0.001) and age < 10 years (HR 0.227, 95% CI 0.077-0.666, p = 0.007) were independent predictors of good local-regional progression-free survival (LR-PFS). Adjuvant radiation therapy (HR 0.301, 95% CI 0.110-0.828, p = 0.020) and age < 10 years (HR 0.359, 95% CI 0.131-0.983, p = 0.046) were significant predictors for favorable OS in the multivariate model.

CONCLUSIONS

Due to the rarity of the disease, a poor outcome of PIRMS was demonstrated based on the pooled cohort. Use of radiation was associated with improved outcomes and should be considered to improve OS/LR-PFS. Further study is required to identify the optimal treatment regimen.Systematic review no.: CRD42019121249 (crd.york.ac.uk/PROSPERO/).

VIVA (vinorelbine, ifosfamide, vincristine, actinomycin-D): A new regimen in the armamentarium of systemic therapy for high-risk rhabdomyosarcoma

The study reports the treatment feasibility, and secondly efficacy, of a novel chemotherapy regimen, which adds vinorelbine to the ifosfamide-vincristine-actinomycin-D combination (VIVA regimen), used in four patients with high-risk rhabdomyosarcoma. All patients received nine cycles of the VIVA regimen followed by maintenance chemotherapy with vinorelbine and cyclophosphamide. All patients experienced significant hematological toxicity, but no other major complications (in particular neurotoxicity) or required treatment dose modifications. We observed a major response after three cycles in all patients, and they remained alive after a median follow up of 11 months from diagnosis.

Management of Refractory Pediatric Sarcoma: Current Challenges and Future Prospects

Paediatric sarcomas are a heterogeneous group of disorders constituting bone sarcoma and various soft tissue sarcomas. Almost one-third of these presents with metastasis at baseline and another one-third recur after initial curative treatment. There is a huge unmet need in this cohort in terms of curative options and/or prolongation of survival. In this review, we have discussed the current treatment options, challenges and future strategies of managing relapsed/refractory paediatric sarcomas. Upfront risk-adapted treatment with multidisciplinary management remains the main strategy to prevent future recurrence or relapse of the disease. In the case of limited local and/or systemic relapse or late relapse, initial multimodality management can be administered. In treatment-refractory cases or where cure is not feasible, the treatment options are limited to novel therapeutics, immunotherapeutic approach, targeted therapies, and metronomic therapies. A better understanding of disease biology, mechanism of treatment refractoriness, identifications of driver mutation, the discovery of novel targeted therapies, cellular vaccine and adapted therapies should be explored in relapsed/refractory cases. Close national and international collaboration for translation research is needed to fulfil the unmet need.

Up-regulation of GLI1 in vincristine-resistant rhabdomyosarcoma and Ewing sarcoma

Background

The clinical significance of GLI1 expression either through canonical Hedgehog signal transduction or through non-canonical mechanisms in rhabdomyosarcoma (RMS) or Ewing sarcoma (EWS) is incompletely understood. We tested a role for Hedgehog (HH) signal transduction and GL11 expression in development of vincristine (VCR) resistance in RMS and EWS.

Methods

We characterized baseline expression and activity of HH pathway components in 5 RMS (RD, Rh18, Ruch-2, Rh30, and Rh41) and 5 EWS (CHLA9, CHLA10, TC32, CHLA258, and TC71) cell lines. We then established VCR-resistant RMS and EWS cell lines by exposing cells to serially increasing concentrations of VCR and determining the IC₅₀. We defined resistance as a ≥ 30-fold increase in IC₅₀ compared with parental cells. We determined changes in gene expression in the VCR-resistant cells compared with parental cells using an 86-gene cancer drug resistance array that included GLI1 and tested the effect of GLI1 inhibition with GANT61 or GLI1 siRNA on VCR resistance.

Results

We found evidence for HH pathway activity and GLI1 expression in RMS and EWS cell lines at baseline, and evidence that GLI1 contributes to survival and proliferation of these sarcoma cells. We were able to establish 4 VCR-resistant cell lines (Ruch-2VR, Rh30VR, Rh41VR, and TC71VR). GLI1 was significantly up-regulated in the Rh30VR, Rh41VR, and TC71VR cells. The only other gene in the drug resistance panel that was significantly up-regulated in each of these VCR-resistant cell lines compared with their corresponding parental cells was the GLI1 direct target and multidrug resistance gene, ATP-binding cassette sub-family B member 1 (MDR1). We established major vault protein (MVP), which was up-regulated in both vincristine-resistant alveolar RMS cell lines (Rh30VR and Rh41VR), as another direct target of GLI1 during development of drug resistance. Treatment of the VCR-resistant cell lines with the small molecule inhibitor GANT61 or GLI1 siRNA together with VCR significantly decreased cell viability at doses that did not reduce viability individually.

Conclusions

These experiments demonstrate that GLI1 up-regulation contributes to VCR resistance in RMS and EWS cell lines and suggest that targeting GLI1 may benefit patients with RMS or EWS by reducing multidrug resistance.

Current and Future Treatment Strategies for Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children, and can be subcategorized histologically and/or based on PAX-FOXO1 fusion gene status. Over the last four decades, there have been no significant improvements in clinical outcomes for advanced and metastatic RMS patients, underscoring a need for new treatment options for these groups. Despite significant advancements in our understanding of the genomic landscape and underlying biological mechanisms governing RMS that have informed the identification of novel therapeutic targets, development of these therapies in clinical trials has lagged far behind. In this review, we summarize the current frontline multi-modality therapy for RMS according to pediatric protocols, highlight emerging targeted therapies and immunotherapies identified by preclinical studies, and discuss early clinical trial data and the implications they hold for future clinical development.

A Perspective on Polo-Like Kinase-1 Inhibition for the Treatment of Rhabdomyosarcomas

Rhabdomyosarcomas are the most common pediatric soft tissue sarcoma and are a major cause of death from cancer in young patients requiring new treatment options to improve outcomes. High-risk patients include those with metastatic or relapsed disease and tumors with PAX3-FOXO1 fusion genes that encode a potent transcription factor that drives tumourigenesis through transcriptional reprogramming. Polo-Like Kinase-1 (PLK1) is a serine/threonine kinase that phosphorylates a wide range of target substrates and alters their activity. PLK1 functions as a pleiotropic master regulator of mitosis and regulates DNA replication after stress. Taken together with high levels of expression that correlate with poor outcomes in many cancers, including rhabdomyosarcomas, it is an attractive therapeutic target. This is supported in rhabdomyosarcoma models by characterization of molecular and phenotypic effects of reducing and inhibiting PLK1, including changes to the PAX3-FOXO1 fusion protein. However, as tumor re-growth has been observed, combination strategies are required. Here we review preclinical evidence and consider biological rationale for PLK1 inhibition in combination with drugs that promote apoptosis, interfere with activity of PAX3-FOXO1 and are synergistic with microtubule-destabilizing drugs such as vincristine. The preclinical effects of low doses of the PLK1 inhibitor volasertib in combination with vincristine, which is widely used in rhabdomyosarcoma treatment, show particular promise in light of recent clinical data in the pediatric setting that support achievable volasertib doses predicted to be effective. Further development of novel therapeutic strategies including PLK1 inhibition may ultimately benefit young patients with rhabdomyosarcoma and other cancers.

Challenges and Opportunities for Childhood Cancer Drug Development

Cancer in children is rare with approximately 15,700 new cases diagnosed in the United States annually. Through use of multimodality therapy (surgery, radiation therapy, and aggressive chemotherapy), 70% of patients will be "cured" of their disease, and 5-year event-free survival exceeds 80%. However, for patients surviving their malignancy, therapy-related long-term adverse effects are severe, with an estimated 50% having chronic life-threatening toxicities related to therapy in their fourth or fifth decade of life. While overall intensive therapy with cytotoxic agents continues to reduce cancer-related mortality, new understanding of the molecular etiology of many childhood cancers offers an opportunity to redirect efforts to develop effective, less genotoxic therapeutic options, including agents that target oncogenic drivers directly, and the potential for use of agents that target the tumor microenvironment and immune-directed therapies. However, for many high-risk cancers, significant challenges remain.

Randomized Phase II Trial of Bevacizumab or Temsirolimus in Combination With Chemotherapy for First Relapse Rhabdomyosarcoma: A Report From the Children's Oncology Group

PURPOSE

The primary aim of this clinical trial was to prioritize bevacizumab or temsirolimus for additional investigation in rhabdomyosarcoma (RMS) when administered in combination with cytotoxic chemotherapy to patients with RMS in first relapse with unfavorable prognosis.

PATIENTS AND METHODS

Patients were randomly assigned to receive bevacizumab on day 1 or temsirolimus on days 1, 8, and 15 of each 21-day treatment cycle, together with vinorelbine on days 1 and 8, and cyclophosphamide on day 1 for a maximum of 12 cycles. Local tumor control with surgery and/or radiation therapy was permitted after 6 weeks of treatment. The primary end point was event-free survival (EFS). Radiographic response was assessed at 6 weeks. The study had a phase II selection that was design to detect a 15% difference between the two regimens (α = .2; 1-β = 0.8; two sided test).

RESULTS

Eighty-seven of 100 planned patients were enrolled when the trial was closed after the second interim analysis after 46 events occurred in 68 patients with sufficient follow-up. The O'Brien Fleming boundary at this analysis corresponded to a two-sided P value of .058 with an observed two-sided P value of .003 favoring temsirolimus. The 6-month EFS for the bevacizumab arm was 54.6% (95% CI, 39.8% to 69.3%) and 69.1% (95% CI, 55.1% to 83%) for the temsirolimus arm. Objective response rates were 28% (95% CI, 13.7% to 41.3%) and 47% (95% CI, 31.5% to 63.2%) for the bevacizumab and temsirolimus arms, respectively (P = .12) and, 28% of patients on bevacizumab and 11% on temsirolimus had progressive disease at 6 weeks.

CONCLUSION

Patients who received temsirolimus had a superior EFS compared with bevacizumab. Temsirolimus has been selected for additional investigation in newly diagnosed patients with intermediate-risk RMS.

Successful use of frameless stereotactic radiosurgery for treatment of recurrent brain metastases in an 18-month-old child

There are very few reported cases of stereotactic radiosurgery (SRS) delivered in children under 3 years of age. We report an 18-month-old boy with metastatic recurrence of undifferentiated round cell sarcoma to the brain which was treated with chemotherapy, resection and robotic frameless SRS. Frameless SRS was delivered without technical difficulties, acute adverse events, or clinical sequelae 1.5 months post-radiation. Longer term follow-up will be needed to evaluate local tumor control and effects on neurocognitive development, endocrine function and growth. This report adds to the literature of the few reported cases of successfully attempted SRS in very young children.

Rhabdomyosarcoma diagnosed in the first year of life: Localized, metastatic, and relapsed disease. Outcome data from five trials and one registry of the Cooperative Weichteilsarkom Studiengruppe (CWS)

BACKGROUND

Rhabdomyosarcoma (RMS) diagnosed during the first year of life is reported to have poor outcome. Little is known about treatment and outcome data of relapsed disease (RD).

METHODS

Characteristics, treatment, and outcome of 155 patients ≤ 12 months registered within the Cooperative Weichteilsarkom Studiengruppe (CWS) between 1981 and 2016 were evaluated.

RESULTS

Localized disease (LD) was diagnosed in 144 patients and metastatic disease (MD) in 11. The histological diagnosis was alveolar (RMA) (n = 38, 23/25 examined patients PAX7/3:FOXO1-positive), embryonal (RME) (n = 100), botryoid (n = 10), anaplastic (n = 1), and spindle-cell RMS (n = 6). Multimodal treatment including conventional (age-adjusted) chemotherapy (CHT) (n = 150), resection (n = 137), and radiotherapy (RT) (n = 37) was administered. Complete remission was achieved in 129 of 144 patients with LD. RD occurred in 51 infants at a median age of 1.7 years (range, 0.3-8.8). Sixty-three percent of patients with RMA suffered RD, in contrast to 28% of patients with RME. Relapse treatment consisted of conventional CHT (n = 48), resection (n = 28), and RT (n = 21). The pattern of relapse and best resection were significant prognostic factors for patients with RD (P = 0.000 and P = 0.002). Late effects occurred as secondary malignancies in 6%, long-term toxicity in 21%, and resection-related impairment in 33% of the 105 surviving patients. The 5-year event-free survival and overall survival for infants with initial LD were 51% and 69%, 14% and 14% for patients with initial MD and 39% and 41% for relapsed patients, respectively.

CONCLUSION

Multimodal treatment including microscopically complete resection is strongly recommended to achieve a good prognosis in LD and RD of infants with RMS.

Risk-based treatment for patients with first relapse or progression of rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

The purpose of this study was to evaluate risk and response-based multi-agent therapy for patients with rhabdomyosarcoma (RMS) at first relapse.

METHODS

Patients with RMS and measurable disease at first relapse with unfavorable-risk (UR) features were randomized to a 6-week phase 2 window with 1 of 2 treatment schedules of irinotecan with vincristine (VI) (previously reported). Those with at least a partial response to VI continued to receive 44 weeks of multi-agent chemotherapy including the assigned VI regimen. UR patients who did not have measurable disease at study entry, did not have a radiographic response after the VI window, or declined VI window therapy received 31 weeks of multi-agent chemotherapy including tirapazamine (TPZ) at weeks 1, 4, 10, 19, and 28. Favorable-risk (FR) patients received 31 weeks of the same multi-agent chemotherapy without VI and TPZ.

RESULTS

One hundred thirty-six eligible patients were enrolled. For 61 patients not responding to VI, the 3-year failure-free survival (FFS) and overall survival (OS) rates were 17% (95% confidence interval [CI], 8%-29%) and 24% (13%-37%), respectively. For 30 UR patients not treated with VI, the 3-year FFS and OS rates were 21% (8%-37%) and 39% (20%-57%), respectively. FR patients had 3-year FFS and OS rates of 79% (47%-93%) and 84% (50%-96%), respectively. There were no unexpected toxicities.

CONCLUSIONS

Patients with UR RMS at first relapse or disease progression have a poor prognosis when they are treated with this multi-agent therapy, whereas FR patients have a higher chance of being cured with second-line therapy.

Addition of Vincristine and Irinotecan to Standard Therapy in a Patient With Refractory High-risk Hepatoblastoma Achieving Long-term Relapse-free Survival

Children with metastatic hepatoblastoma have a poor prognosis, even with dose intensification of cisplatin and doxorubicin. Vincristine and irinotecan have demonstrated activity in high risk disease. This report describes a 3-year-old girl with metastatic hepatoblastoma with unresectable disease after 5 cycles of cisplatin, 5-fluorouracil, vincristine, and doxorubicin who had a complete response of her metastatic disease to vincristine and irinotecan (intravenous and oral forms), allowing surgical resection of her liver disease. She remains in remission 48 months since therapy completion.

Management of recurrent Ewing sarcoma: challenges and approaches

Although many patients with newly diagnosed Ewing sarcoma can become long-term survivors, relapse remains an important clinical problem for which there is no standard approach. Several prognostic factors have been identified, and these may help guide patient counseling and therapy decisions. A variety of chemotherapy regimens have produced responses in patients with recurrent Ewing sarcoma, but no comparative studies have been completed to show superiority of any one particular approach. In addition, the optimum length of therapy for salvage regimens and use of local control measures remains unknown. The likelihood of cure remains low and the gaps in our knowledge are great, and so enrollment on clinical trials should be strongly encouraged for these patients when feasible. Because Ewing sarcoma is relatively rare, some pediatric and adult oncologists may be less familiar with the management of relapsed patients. In this review, we address common questions facing the clinician and patient, and provide an update on new strategies for therapy.

Addition of Vincristine and Irinotecan to Vincristine, Dactinomycin, and Cyclophosphamide Does Not Improve Outcome for Intermediate-Risk Rhabdomyosarcoma: A Report From the Children's Oncology Group

Purpose Intermediate-risk rhabdomyosarcoma (RMS) includes patients with either nonmetastatic, unresected embryonal RMS (ERMS) with an unfavorable primary site or nonmetastatic alveolar RMS (ARMS). The primary aim of this study was to improve the outcome of patients with intermediate-risk RMS by substituting vincristine and irinotecan (VI) for half of vincristine, dactinomycin, and cyclophosphamide (VAC) courses. All patients received a lower dose of cyclophosphamide and earlier radiation therapy than in previous trials. Patients and Methods Patients were randomly assigned at study entry to either VAC (cumulative cyclophosphamide dose, 16.8 g/m²) or VAC/VI (cumulative cyclophosphamide dose, 8.4 g/m²) for 42 weeks of therapy. Radiation therapy started at week 4, with individualized local control plans permitted for patients younger than 24 months. The primary study end point was event-free survival (EFS). The study design had an 80% power (5% one-sided α-level) to detect an improved long-term EFS from 65% (with VAC) to 76% (with VAC/VI). Results A total of 448 eligible patients were enrolled in the study. At a median follow-up of 4.8 years, the 4-year EFS was 63% with VAC and 59% with VAC/VI ( P = .51), and 4-year overall survival was 73% for VAC and 72% for VAC/VI ( P = .80). Within the ARMS and ERMS subgroups, no difference in outcome by treatment arm was found. Severe hematologic toxicity was less common with VAC/VI therapy. Conclusion The addition of VI to VAC did not improve EFS or OS for patients with intermediate-risk RMS. VAC/VI had less hematologic toxicity and a lower cumulative cyclophosphamide dose, making VAC/VI an alternative standard therapy for intermediate-risk RMS.

Vincristine, irinotecan, and temozolomide treatment for refractory/relapsed pediatric solid tumors: A single center experience

BACKGROUND

Although the survival of pediatric cancer has increased dramatically in the last decades, the survival of refractory, relapsed, and metastatic cases is still dismal. The combination of irinotecan and temozolomide has shown activity against refractory/relapsed pediatric solid tumors.

METHOD

Thirty-four children with refractory/relapsed solid tumors who had previously been heavily pretreated and who were given vincristine, irinotecan, and temozolomide as third- or further line chemotherapy during 2004-2015 were evaluated.

RESULTS

Patients were diagnosed with Ewing sarcoma (n = 15), rhabdomyosarcoma (n = 8), neuroblastoma (n = 8), osteosarcoma (n = 2), and Wilms' tumor (n = 1). Thirty patients presented with disease progression on therapy and the other four presented with relapsing. A total of 141 cycles were administered. Radiotherapy was used in 17 patients and surgery in 4 as local therapy. Among all patients, 6 had complete response, 3 had partial response, 14 had stable disease, and 11 had progressive disease. The objective response was 26.4% (complete response + partial response) and median survival duration was six months. The first and second year overall survival rates were 22.3% and 16.8%. The objective response in Ewing sarcoma patients was 40%. Diarrhea was the most common toxicity and 14 (10%) courses were associated with grade 3-4 diarrhea.

CONCLUSIONS

In heavily pretreated patients with refractory/relapsed solid tumors, the vincristine, irinotecan, and temozolomide regimen seemed promising in Ewing sarcoma patients and was well tolerated.

Is there a role for salvage re-irradiation in pediatric patients with locoregional recurrent rhabdomyosarcoma? Clinical outcomes from a multi-institutional cohort

BACKGROUND AND PURPOSE

Limited data exist detailing the role of salvage reirradiation following local-regional recurrence (LR) in previously irradiated pediatric patients with rhabdomyosarcoma (RMS).

MATERIALS AND METHODS

We evaluated outcomes and prognostic factors in a multi-institutional cohort of 23 patients with LR-only (N = 19) or LR with distant failure (N = 4) RMS managed with (N = 12) or without (N = 11) re-irradiation who were treated from 1996 to 2012.

RESULTS

At a median follow-up of 4.6 years from LR, 7 (30%) patients were alive and 5 (22%) had no evidence of disease. Median OS and PFS from LR were 19.3 and 16.9 months, respectively. LFFS and DFFS at 3 years from relapse were 54% and 56%, respectively. Salvage re-irradiation occurred in 12 (52%) patients, with 9 (75%) receiving resection before re-irradiation. Patients classified as low-risk at diagnosis with favorable primary tumor location had improved 3-year PFS 80% (95% CI 51.6-100%) vs. 47.1% (95% CI 27.3-81.2%), p = 0.066], and OS 80% [(95% CI 22.4-100%) vs. 47.1% (95% CI 27.3-81.3%), p = 0.051] following LR. Median LFFS and OS in unirradiated vs. re-irradiated patients was 12.4 vs. 19.6 (p = 0.1) and 18.8 vs. 26.1 months (p = 0.46). No patients experienced ≥grade 4 acute toxicity from re-irradiation. LR failure was a component of cancer-related death in 60% vs. 40% of the unirradiated and re-irradiated group (p = 0.02).

CONCLUSION

Salvage re-irradiation appears tolerable with acceptable morbidity and may reduce the risk of subsequent LR as a component of death in patients with LR RMS.

SN-38 Conjugated Gold Nanoparticles Activated by Ewing Sarcoma Specific mRNAs Exhibit In Vitro and In Vivo Efficacy

The limited delivery of chemotherapy agents to cancer cells and the nonspecific action of these agents are significant challenges in oncology. We have previously developed a customizable drug delivery and activation system in which a nucleic acid functionalized gold nanoparticle (Au-NP) delivers a drug that is selectively activated within a cancer cell by the presence of an mRNA unique to the cancer cell. The amount of drug released from sequestration to the Au-NP is determined by both the presence and the abundance of the cancer cell specific mRNA in a cell. We have now developed this technology for the potent, but difficult to deliver, topoisomerase I inhibitor SN-38. Herein, we demonstrate both the efficient delivery and selective release of SN-38 from gold nanoparticles in Ewing sarcoma cells with resulting efficacy in vitro and in vivo. These results provide further preclinical validation for this novel cancer therapy and may be extendable to other cancers that exhibit sensitivity to topoisomerase I inhibitors.

Consensus and controversies regarding the treatment of rhabdomyosarcoma

Optimal treatment of rhabdomyosarcoma (RMS) requires multidisciplinary approach, incorporating chemotherapy with local control. Although current therapies are built on cooperative group trials, a comprehensive standard of care to guide clinical decision making has been lacking, especially for relapsed patients. Therefore, we assembled a panel of pediatric and adolescent and young adult sarcoma experts to develop treatment guidelines for managing RMS and to identify areas in which further research is needed. We created algorithms incorporating evidence-based care for patients with RMS, emphasizing the importance of clinical trials and close integration of all specialties involved in the care of these patients.

VIncristine, irinotecan, and temozolomide in children and adolescents with relapsed rhabdomyosarcoma

BACKGROUND

The combination of vincristine, irinotecan, and temozolomide (VIT) is often used to treat children and adolescents with relapsed rhabdomyosarcoma (RMS); however, the outcome of these patients has not been previously described.

PROCEDURES

We sought to determine the response rate (RR) and progression-free survival (PFS) for patients with relapsed RMS treated with VIT by retrospective review of patients treated at five tertiary care hospitals. Prior treatment with irinotecan was permitted.

RESULTS

Among 19 patients with a median age of 8 years (range 2-17 years), 12 (63%) were males and 12 (63%) had embryonal histology. Median time to relapse from initial diagnosis was 16 months (range 2.8-45 months). VIT was used as first, second, third, or fourth line of therapy in four (21%), seven (37%), six (32%), and two (10%) patients, respectively. Four patients received VIT as adjuvant therapy following radiation and/or surgery. Therefore, among 15 evaluable patients, the best response to VIT was 0 (complete response, CR), 0 (partial response, PR), 4 (stable disease, SD), and 11 (progressive disease, PD) for an overall clinical benefit rate (CR + PR + SD) of 26.7% (95% CI: 7.8-55.1%). After a median follow-up of 8 months, 2 (10%) patients were alive without disease, 3 (16%) were alive with disease, and 14 (74%) patients died of PD. PFS at 3 months was 23% (95% CI: 5.7-46.7%).

CONCLUSIONS

VIT therapy in combination with adequate local control is associated with some disease control in patients with first relapse RMS and may be another reasonable option to offer patients as salvage therapy.

Rhabdomyosarcoma, Ewing Sarcoma, and Other Round Cell Sarcomas

Several recent advances have been made in the diagnosis and therapy of malignant small round cell tumors that affect children, particularly in rhabdomyosarcoma, Ewing sarcoma, and other round cell sarcomas. These advances have provided new insights into the pathologic, histologic, and genomic characterization of specific tumor subtypes, which has led to the identification of novel therapeutic targets and improved stratification of risk. This has, in turn, led to improved efficacy in clinical trials of new drug combinations, thereby increasing the survival of patients with newly diagnosed and refractory or recurrent round cell sarcomas. Here, we review the progress that has been made using genomics to identify novel pathologic genomic rearrangements, as well as therapeutic targets. We also describe how clinical and molecular factors have helped refine risk stratification and therapies that have led to improved clinical outcomes in patients with round cell sarcomas.