DIPG Harbors Alterations Targetable by MEK Inhibitors, with Acquired Resistance Mechanisms Overcome by Combinatorial Inhibition.

The survival of children with diffuse intrinsic pontine glioma (DIPG) remains dismal, with new treatments desperately needed. In a prospective biopsy-stratified clinical trial, we combined detailed molecular profiling and drug screening in newly established patient-derived models in vitro and in vivo. We identified in vitro sensitivity to MEK inhibitors in DIPGs harboring MAPK pathway alterations, but treatment of patient-derived xenograft models and a patient at relapse failed to elicit a significant response. We generated trametinib-resistant clones in a BRAFG469V model through continuous drug exposure and identified acquired mutations in MEK1/2 with sustained pathway upregulation. These cells showed hallmarks of mesenchymal transition and expression signatures overlapping with inherently trametinib-insensitive patient-derived cells, predicting sensitivity to dasatinib. Combined trametinib and dasatinib showed highly synergistic effects in vitro and on ex vivo brain slices. We highlight the MAPK pathway as a therapeutic target in DIPG and show the importance of parallel resistance modeling and combinatorial treatments for meaningful clinical translation. SIGNIFICANCE: We report alterations in the MAPK pathway in DIPGs to confer initial sensitivity to targeted MEK inhibition. We further identify for the first time the mechanism of resistance to single-agent targeted therapy in these tumors and suggest a novel combinatorial treatment strategy to overcome it in the clinic. This article is highlighted in the In This Issue feature, p. 587.

Antitumor activity without on-target off-tumor toxicity of GD2-chimeric antigen receptor T cells in patients with neuroblastoma.

The reprogramming of a patient's immune system through genetic modification of the T cell compartment with chimeric antigen receptors (CARs) has led to durable remissions in chemotherapy-refractory B cell cancers. Targeting of solid cancers by CAR-T cells is dependent on their infiltration and expansion within the tumor microenvironment, and thus far, fewer clinical responses have been reported. Here, we report a phase 1 study (NCT02761915) in which we treated 12 children with relapsed/refractory neuroblastoma with escalating doses of second-generation GD2-directed CAR-T cells and increasing intensity of preparative lymphodepletion. Overall, no patients had objective clinical response at the evaluation point +28 days after CAR-T cell infusion using standard radiological response criteria. However, of the six patients receiving ≥108/meter2 CAR-T cells after fludarabine/cyclophosphamide conditioning, two experienced grade 2 to 3 cytokine release syndrome, and three demonstrated regression of soft tissue and bone marrow disease. This clinical activity was achieved without on-target off-tumor toxicity. Targeting neuroblastoma with GD2 CAR-T cells appears to be a valid and safe strategy but requires further modification to promote CAR-T cell longevity.

A tailored molecular profiling programme for children with cancer to identify clinically actionable genetic alterations.

BACKGROUND: For children with cancer, the clinical integration of precision medicine to enable predictive biomarker-based therapeutic stratification is urgently needed. METHODS: We have developed a hybrid-capture next-generation sequencing (NGS) panel, specifically designed to detect genetic alterations in paediatric solid tumours, which gives reliable results from as little as 50 ng of DNA extracted from formalin-fixed paraffin-embedded (FFPE) tissue. In this study, we offered an NGS panel, with clinical reporting via a molecular tumour board for children with solid tumours. Furthermore, for a cohort of 12 patients, we used a circulating tumour DNA (ctDNA)-specific panel to sequence ctDNA from matched plasma samples and compared plasma and tumour findings. RESULTS: A total of 255 samples were submitted from 223 patients for the NGS panel. Using FFPE tissue, 82% of all submitted samples passed quality control for clinical reporting. At least one genetic alteration was detected in 70% of sequenced samples. The overall detection rate of clinically actionable alterations, defined by modified OncoKB criteria, for all sequenced samples was 51%. A total of 8 patients were sequenced at different stages of treatment. In 6 of these, there were differences in the genetic alterations detected between time points. Sequencing of matched ctDNA in a cohort of extracranial paediatric solid tumours also identified a high detection rate of somatic alterations in plasma. CONCLUSION: We demonstrate that tailored clinical molecular profiling of both tumour DNA and plasma-derived ctDNA is feasible for children with solid tumours. Furthermore, we show that a targeted NGS panel-based approach can identify actionable genetic alterations in a high proportion of patients.

Results from the UK Children's Cancer and Leukaemia Group study of extracranial germ cell tumours in children and adolescents (GCIII).

BACKGROUND: For extracranial malignant germ cell tumours (MGCTs) in the UK, the GCII study used carboplatin-based chemotherapy (JEb) and demonstrated equivalent survival to cisplatin-containing protocols. GCIII, a single-arm observational study, used new risk stratification, replaced consolidation chemotherapy with a standard number of cycles and introduced surveillance for all stage I MGCTs. Pure teratomas were registered to understand their natural history. METHODS: Patients with MGCTs were stratified to three risk groups - low risk (LR), intermediate risk (IR) and high risk (HR), using stage and prognostic factors. Patients with alpha fetoprotein (AFP) >10,000 kU/L, stage IV disease (except testis <5 years and all germinomas) or stage II-IV mediastinal tumour were classified HR. Stage I tumours (LR) received chemotherapy only if disease progressed. IR and HR patients received 4 and 6 JEB cycles, respectively. Carboplatin dose was calculated using glomerular filtration rate to give an area under the curve of 7.9 ml/m2.min. RESULTS: Eighty-six patients with MGCTs were enrolled from 2005 to 2009: 59% female, median age, 5.7 years. Twenty-five patients were LR, 21 IR and 38 HR. Seven LR patients had disease progression; all were successfully treated with chemotherapy. Overall survival (OS) for the whole group was 97%; 5-year event-free survival for JEb-treated patients was 92%, and OS, 95%. JEb was well tolerated with no observed significant hearing or renal side-effects. There was no discernible difference in carboplatin dose whether calculated by body surface area or creatinine clearance. Forty-seven patients with teratoma were managed with surgery and one had malignant transformation. CONCLUSION: Carboplatin-based chemotherapy as part of a risk-stratified approach leads to excellent survival in paediatric MGCTs, minimising potential burden of long-term effects.

What do families want to improve in the management of paediatric febrile neutropenia during anti-cancer treatment? Report of a patient/public involvement group.

BACKGROUND: This study reports how parents and young people who had an experience offebrile neutropenia (FN) improved the design of a trial to inform the management of this condition. Five parents, a young person who had completed treatment and three clinician-researchers contributed. METHODS: The group was formed after an invitation on social media and met via video conference. Many participants were from an existing childhood-cancer parent-involvement group. The initial questions asked during discussion were about the importance of the topic, the views on the need for a trial, which important outcomes should be measured and the practical aspects which would make it easier or more difficult for people to take part in it. The conversation occurred for an entire afternoon, was audio and video recorded, transcribed, analysed and checked by those involved. The fifth parent added to this via email. RESULTS: The group altered the trial structure by proposing randomising of each child to one of the two management methods through the whole of their anti-cancer treatment, rather than randomising the study sites or the child at each visit. They felt that even if people declined taking part in the study in the first weeks of diagnosis, their views might change and they should be allowed to consent later. They also proposed methods of collecting important patient and family data, enriching the medical information gained in the study. Active follow-up, negotiated for each individual family, was also suggested. CONCLUSION: Trials for improving the management of FN in children and young people who are undergoing anti-cancer treatments should consider individual-patient randomisation, collection of 'quality of life' and 'experience of care' aspects using digital and paper-based methods, engage families in shared decision-making about management options and ensure adequate supportive information is available and accessible to all patients regardless of background, geographical location or age.

Triple therapy of vincristine, bleomycin and etoposide for children with Kaposi sarcoma: Results of a study in Malawian children.

BACKGROUND: Kaposi sarcoma (KS) is the most common paediatric cancer in human immunodeficiency virus (HIV) endemic countries of sub-Saharan Africa, but there is little research on management and outcomes. METHODS: Children with KS at Queen Elizabeth Central Hospital, Blantyre, Malawi treated between August 2012 and March 2015 with six courses of vincristine, bleomycin and etoposide combination chemotherapy, including antiretroviral therapy (ART) if HIV infected, were studied and outcomes compared with previously reported results. FINDINGS: Fifty-six children were included; 38 (68%) were male; and 48 (86%) were HIV positive, of whom 36 (77%) were on ART at diagnosis. Median age at diagnosis was 8 years (interquartile range [IQR] 3-12) and median follow-up was 16.9 months (IQR 3.4-36.4). Quality of life improved in 45 (80%) children; the median Lansky Score increased from 80% pre-treatment to 100% post-treatment. Eighteen (32%) children had complete response to treatment. At 12 months, overall survival was 71% (95% confidence interval [CI] 56-82) and event-free survival (event = death, loss to follow-up or relapse) was 50% (95% CI 36-63). At 1 year, the risk of loss to follow-up was 13.4%. In a previous, same-site, randomized controlled study of vincristine monotherapy, vincristine and bleomycin, or oral etoposide, oral etoposide monotherapy had the best outcome with survival at 12 month of 66% (95% CI 46-80) and event-free survival of 52% (95% CI 33-68); however, loss to follow-up was not reported. CONCLUSION: Overall survival, event-free survival and quality of life appear to have improved with this three-agent combination chemotherapy; however larger, randomized studies are needed to determine optimal management.

The use of anthracyclines in the treatment of endemic Burkitt lymphoma.

Burkitt lymphoma is the most common malignancy in children in Malawi, the world's poorest country, where there is a long history of treating this disease using a 28-day cyclophosphamide-based protocol. Stage III/IV disease has had poor outcomes. In an attempt to improve the outcome for higher stage disease, anthracyclines were added to the existing protocol. The disease-free (DFS) and overall survival (OS) of 58 children with cytologically confirmed Burkitt lymphoma admitted during 2012-2014 and treated using this protocol were calculated. Six (10%) children had stage I disease, ten (17%) stage II and 42 stage III or IV (73%). Overall 12-month DFS (OS) was 68·5% (72·9%); for stage I disease 100% (100%), stage II 56·2% (60%), stage III/IV 66·3% (72·2%). The DFS was significantly improved from the previous protocol (P = 8 × 10-4 ). The addition of doxorubicin to stage III and IV disease resulted in a markedly improved DFS. Anthracyclines are deliverable in resource-poor settings and possibly improve the survival of children with Burkitt lymphoma.

Relapsed or poorly responsive nodular lymphocyte predominant Hodgkin lymphoma in children and adolescents - a report from the United Kingdom's Children's Cancer and Leukaemia Study Group.

There is a paucity of data on the treatment outcome in children with relapsed or poorly responsive nodular lymphocyte predominant Hodgkin lymphoma (nLPHL). This retrospective report evaluates the treatment outcome in a national cohort of children with relapsed or poorly responsive nLPHL. A total of 37 patients, 22 with relapsed and 15 with poorly responding disease, are the subjects of this report. Of the 22 patients with relapsed nLPHL, 11 had relapsed after primary excision biopsy, 10 after chemotherapy and 1 after chemotherapy and involved field radiotherapy. The majority had localized disease at relapse. The median time to relapse was 8 months after chemotherapy and 11 months after excision biopsy. Seven of the 15 patients with poorly responding nLPHL had variant histology. Three patients with initial poor response did not receive any further treatment and have had no disease progression. Transformation to diffuse large B cell lymphoma, in addition to evolution from typical to variant nLPHL occurred in one patient each. Thirty-four patients have been successfully re-treated with second chemotherapy or radiotherapy. Multiple relapses were uncommon but treatable. Relapse or poorly responsive nLPHL is fully salvageable with either additional chemotherapy and or radiotherapy.

Outcome is unchanged by adding vincristine upfront to the Malawi 28-day protocol for endemic Burkitt lymphoma.

BACKGROUND: We previously reported a 28-day treatment protocol for children with endemic Burkitt lymphoma (BL) which included four doses of cyclophosphamide (CPM), intrathecal methotrexate and hydrocortisone (IT MTX/HC) at Queen Elizabeth Central Hospital (QECH) in Malawi which resulted in an Event-Free Survival (EFS) of 50% at 1 year. METHODS: In an attempt to improve survival whilst maintaining acceptable toxicity, brevity, low-cost and a standard treatment for all patients, four doses of vincristine (VCR) at 1.5 mg/m(2) were added to the backbone of CPM 40 mg/kg on day 1 and 60 mg/kg on days 8,18 and 28 and IT MTX /HC 12.5 mg on days 1,8,18 and 28. RESULTS: Seventy cytology confirmed cases of BL, 42 males and 28 females with a median age of 80 years, were treated with this protocol between January 2010 and April 2012. Four percent had St Jude Stage I disease; 29% Stage II; 30% Stage III and 37% Stage IV. Disease site in order of frequency was face (64%); abdomen (47%); CSF (26%) and paraspinal (17%). There were two on-treatment deaths. Sixty-three percent required antibiotics and 19% required blood transfusion. Eighty-one percent of patients achieved complete clinical remission at day 28. Overall predicted EFS at 1 year was 48%; 100% in Stage I, 83% in Stage II, 24% in Stage III and 32% in Stage IV disease. EFS was significantly worse in patients with Stage III/IV disease (P = 0.002) and paraplegia (P = 0.002). CONCLUSION: The addition of vincristine to the Malawi 28 day BL treatment protocol did not improve survival.

Kaposi's sarcoma in children: an open randomised trial of vincristine, oral etoposide and a combination of vincristine and bleomycin.

INTRODUCTION: Kaposi's sarcoma (KS) is a common childhood cancer in places where HIV is endemic and access to antiretroviral therapy (ART) is delayed. Despite this there are no randomised trials to compare and assess chemotherapeutic regimens. METHOD: An open label, randomised trial comparing intravenous vincristine alone, vincristine and bleomycin and oral etoposide, was carried out in children with Kaposi's sarcoma in the Queen Elizabeth Central Hospital, Blantyre, Malawi. HIV infected children were given ART after 2-3 courses of chemotherapy if they were not already on treatment. Neither HIV nor widespread KS are curable and treatment is aimed at disease reduction and improved quality of life. Tumour reduction was assessed by measuring the size of sentinel KS nodules and quality of life (QoL) by using the Lansky score. Follow up was until death or for one year. FINDINGS: 92 children were enrolled of whom 46% were naïve to ART; 10 (11%) were HIV negative. Survival was not influenced by age or gender but was better in the oral etoposide and the vincristine and bleomycin groups. P=0.0045. The group receiving oral etoposide had a better quality of life. Toxicity was not significant, and any drop in haemoglobin or white cell count could have been causally related to HIV infection rather than cytotoxic therapy. CONCLUSION: Oral etoposide is a safe, effective treatment to contain KS and improve QoL which can be achieved without many visits to the hospital and intravenous injections.

The contribution of infections to neonatal deaths in England and Wales.

This study used anonymized death certificate data to determine the contribution of specific infections to neonatal deaths in England and Wales between 2003 and 2005. Infection was recorded in 11% of deaths, with two-thirds occurring in premature neonates. Group B Streptococcus was indicated in 32% of death certificates that specified a bacterial infection and in 11% of all infection-related deaths.

Hereditary leiomyomatosis and renal cell carcinoma: very early diagnosis of renal cancer in a paediatric patient.

Hereditary leiomyomatosis and renal cell cancer is a hereditary cancer syndrome in which affected individuals are at risk for cutaneous and uterine leiomyomas, and renal cancer. Previous reports have stressed the aggressiveness of the renal tumours, often with early metastasis, despite small primary tumour size. Almost all the previously reported patients were adults, and different studies showed variability in penetrance for the renal tumours. We report a patient in whom renal cancer was detected at the age of 11 years at his first routine screening imaging after he was found to carry a fumarate hydratase gene mutation (c.1189G > A) transmitted from his mother. This report serves to emphasize the need to improve guidelines for screening of at risk individuals, including the necessity for predictive genetic testing and early institution of tumour surveillance in childhood.