Hypofractionated re-irradiation for diffuse intrinsic pontine glioma.

BACKGROUND: Re-irradiation (reRT) increases survival in locally recurrent diffuse intrinsic pontine glioma (DIPG). There is no standard dose and fractionation for reRT, but conventional fractionation (CF) is typically used. We report our institutional experience of reRT for DIPG, which includes hypofractionation (HF). METHODS: We reviewed pediatric patients treated with brainstem reRT for DIPG at our institution from 2012 to 2022. Patients were grouped by HF or CF. Outcomes included steroid use, and overall survival (OS) was measured from both diagnosis and start of reRT. RESULTS: Of 22 patients who received reRT for DIPG, two did not complete their course due to clinical decline. Of the 20 who completed reRT, the dose was 20-30 Gy in 2-Gy fractions (n = 6) and 30-36 Gy in 3-Gy fractions (n = 14). Median age was 5 years (range: 3-14), median interval since initial RT was 8 months (range: 3-20), and 12 received concurrent bevacizumab. Median OS from diagnosis was 18 months [95% confidence interval: 17-24]. Median OS from start of reRT for HF versus CF was 8.2 and 7.5 months, respectively (p = .20). Thirteen (93%) in the HF group and three (75%) in the CF group tapered pre-treatment steroid dose down or off within 2 months after reRT due to clinical improvement. There was no significant difference in steroid taper between HF and CF (p = .4). No patients developed radionecrosis. CONCLUSION: reRT with HF achieved survival duration comparable to published outcomes and effectively palliated symptoms. Future investigation of this regimen in the context of new systemic therapies and upfront HF is warranted.

A multi-institutional feasibility study of intra-arterial chemotherapy in children with retinoblastoma. A Children's Oncology Group study (COG ARET12P1).

BACKGROUND: Intra-arterial chemotherapy (IA) as a treatment to salvage the eye with advanced retinoblastoma is increasingly utilized based on successes reported by institutions around the world mainly through retrospective studies. OBJECTIVE: To study the feasibility of delivering melphalan directly into the ophthalmic artery in a multi-institutional prospective study in children with newly diagnosed unilateral group D retinoblastoma. METHODS: The Children's Oncology Group (COG) initiated study ARET12P1 in 2014 and was open to nine institutions. Eligible patients older than six months of age were enrolled. The feasibility of delivering three injections of melphalan into the ophthalmic artery every 28 days was assessed. RESULTS: Nine institutions participated in this trial. Fourteen patients were enrolled, two of whom were unevaluable for feasibility. Four patients experienced a feasibility failure. In two patients, the ophthalmic artery could not be accessed for the second IA injection, in one the artery could not be accessed for the first injection, and one patient experienced grade 4 hypotension during the procedure. CONCLUSION: Delivery of prescribed therapy within the context of this study did not meet the feasibility goals of the study with only a 67% feasibility success rate. These results should caution centers that plan to initiate this treatment and suggest investment in training to achieve technical expertise or referral to centers with expertise.

RB1 circulating-tumor DNA in the blood of Retinoblastoma patients increases in untreated patients.

PURPOSE: Circulating tumor DNA (ctDNA) in plasma has been identified in many cancers, including retinoblastoma at diagnosis. We have previously shown that with treatment (enucleation or ophthalmic artery chemosurgery (OAC)) all ctDNA disappears; and if there is persistent plasma ctDNA after treatment metastases develop. The purpose of this study was to determine how the ctDNA RB1 variant allele frequency (VAF) changes in patients with retinoblastoma who have delayed treatment. METHODS: Circulating tumor DNA RB1 was detected and VAF was measured at diagnosis and again prior to any intervention at some time later ranging from 2 to 28 days. RESULTS: Four patients with five ctDNA RB1 mutations were detected at diagnosis and VAF was increased on re-evaluation of the same RB1 mutations in ctDNA. CONCLUSION: In this small cohort, every patient (4) and every RB1 mutation (5) plasma level VAF% increased when measured at two time periods before treatment was instituted suggesting that growing tumors demonstrate increasing plasma ctDNA.

Slipped capital femoral epiphyses: A major on-target adverse event associated with FGFR tyrosine kinase inhibitors in pediatric patients.

Fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitors (TKIs) are increasingly being used off label in pediatrics. Long-term safety data are limited, and serious toxicities unique to pediatrics may emerge. In a retrospective analysis of patients less than 18 years of age with recurrent/refractory FGFR altered gliomas treated with FGFR TKIs at MSKCC (n = 7), we observed slipped capital femoral epiphyses in three of seven patients along with increased linear growth velocity. Clinicians should closely monitor bone health and have a low index of suspicion for serious orthopedic complications including slipped capital femoral epiphyses and inform patients of related risks as part of consent when treating with FGFR TKIs.

Lack of complete response pretransplant is not associated with inferior overall survival for stage 4a metastatic retinoblastoma.

BACKGROUND: Stage 4a metastatic retinoblastoma (RB) is curable with intensive multimodality therapy including myeloablative chemotherapy with autologous stem cell transplant (HDC-ASCT) and involved field radiation therapy (IFRT). To our knowledge, no data exist on the impact of (a) pre-ASCT disease status, and (b) IFRT to sites of metastatic disease post ASCT on survival. PROCEDURE: We retrospectively reviewed patients with stage 4a metastatic RB who underwent induction chemotherapy followed by HDC-ASCT, with or without IFRT, to residual tumor sites at Memorial Sloan Kettering Cancer Center (MSKCC) (n = 24). RESULTS: The degree of postinduction response prior to ASCT did not affect outcome, with 5-year overall survival (OS) of 68% and 86% in patients who achieved complete response (CR) and very good partial response (VGPR)/partial response (PR) prior to ASCT, respectively. IFRT administered post ASCT in patients with possible residual bony metastatic disease increases the likelihood of developing osteosarcoma in the radiation field. CONCLUSION: OS for patients with stage 4a metastatic RB treated with ASCT with VGPR or PR to pretransplant chemotherapy was not significantly different from patients with CR. In addition, IFRT does not seem to be required for bony disease control and increased the likelihood of developing osteosarcoma.

Chemotherapy-induced thrombocytopenia in pediatric oncology: Scope of the problem and opportunities for intervention.

BACKGROUND: Chemotherapy-induced thrombocytopenia (CIT) is a known hematologic complication of oncology treatment. This single-institution study examines the degree with which CIT impacts specific pediatric solid tumor cohorts reflected by platelet transfusion burden and treatment modifications. PROCEDURE: Data regarding clinically relevant CIT were obtained via a retrospective chart review of pediatric solid tumor patients treated at Memorial Sloan Kettering Cancer Center from 2013 to 2020. Patients were stratified based on histologic diagnoses as well as chemotherapy regimen. CIT impact was assessed through platelet transfusion means, chemotherapy dose reductions, and treatment delays. RESULTS: A total of 150 patients were included with mean age 10.3 [0.2-21.0]. Patients receiving therapy for high-risk neuroblastoma and localized Ewing sarcoma, both of which included high-dose cyclophosphamide and doxorubicin, required the most platelet transfusions over the treatment course, with a mean of 13 and 9, respectively. Reduced relative dose intensity (RDI), due in part to CIT, was greatest for the patients receiving therapy for high-risk and intermediate-risk rhabdomyosarcoma. Fifty-six percent of high-risk patients experienced a reduced RDI during the final two cycles of treatment and 69% of intermediate-risk patients experienced one during the final four cycles of treatment. CONCLUSIONS: The impact of CIT varied by the administered chemotherapy regimens and dose intensity of chemotherapy agents. This study demonstrated that CIT causes both marked platelet transfusion burden as well as treatment reduction and delay within certain solid tumor cohorts. This can lend to future studies aimed at reducing the burden of CIT and targeting the most at-risk populations.

Low-grade glioma: A rare second tumor in retinoblastoma survivors.

Retinoblastoma survivors with a germline RB1 mutation are at elevated risk for secondary (nonocular) malignancy, but their risk for low-grade glioma (LGG) is unknown. We performed a retrospective review of the Memorial Sloan Kettering Cancer Center and the NCI databases that revealed that three of the 837 5-year survivors of hereditary retinoblastoma were diagnosed with an LGG and a fourth patient (but unilateral and without a germline mutation) was identified at another center. Retinoblastoma survivors may be at increased risk for LGG.

Retinoblastoma management in 13q deletion syndrome patients using super-selective chemotherapies and other cancer-directed interventions.

BACKGROUND: This study aimed to identify best practices for treating 13q deletion syndrome (13q-) patients with retinoblastoma in the era of super-selective ophthalmic artery chemosurgery (OAC) and intravitreal injection therapy (IVIT). METHODS: Retrospective study of 21 eyes from 14 patients with retinoblastoma and 13q- who were treated at Memorial Sloan Kettering Cancer Center (MSKCC) between May 2006 and May 2020, with a mean follow up of 3.7 years. Ocular survival, patient survival, and treatment toxicities were assessed. RESULTS: Nine of the 12 eyes that underwent OAC/IVIT at MSKCC have been progression free for at least 1 year since their last treatments. Fifteen out of 26 OAC cycles resulted in grade 3-4 hematologic toxicity. There was one death from sepsis in the setting of intravenous chemotherapy (IVC) for metastatic disease that occurred after OAC/IVIT therapy. The 2-year Kaplan-Meier ocular survival estimate for the whole cohort was 75% and for the eyes that received OAC or IVIT at MSKCC 83%. For OAC hematologic toxicities, one platelet transfusion and two filgrastim doses were administered, and one patient was hospitalized for neutropenic fevers. CONCLUSIONS: The majority of 13q- eyes treated with OAC/IVIT-based regimens can be cured, and there were no deaths related to complications from OAC or IVIT. 13q- Patients did have increased risk of systemic treatment complications, even from super-selective chemotherapies. Despite these toxicities, only one patient developed febrile neutropenia, one patient required a blood product transfusion, and two patients received filgrastim for both OAC and IVC complications. PRÉCIS: Children with 13q deletion syndrome with retinoblastoma managed with intra-arterial and intravitreal chemotherapy have excellent patient and ocular survival with acceptable toxicity.

Phase 1 study of pomalidomide in children with recurrent, refractory, and progressive central nervous system tumors: A Pediatric Brain Tumor Consortium trial.

BACKGROUND: Central nervous system (CNS) malignancies are the most common solid tumors among children, and novel therapies are needed to help improve survival. Pomalidomide is an immunomodulatory agent that displays antiangiogenic and cytotoxic activity, making it an appropriate candidate to explore in pediatric CNS tumors. METHODS: A phase 1 first in pediatric trial of pomalidomide was conducted in children with recurrent, progressive, and refractory CNS tumors. The primary objective was to determine the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) when given orally once daily for 21 consecutive days of a 28-day cycle. Once the MTD was established, 12 additional patients were enrolled on expansion cohorts based on age and steroid use. RESULTS: Twenty-nine children were enrolled and 25 were evaluable for dose-limiting toxicity (DLT). The MTD was 2.6 mg/m2 (dose level 2). Four DLTs were observed in three patients at dose level 3 (3.4 mg/m2 ) includeding grade 3 diarrhea, grade 3 thrombocytopenia, grade 3 lung infection, and grade 4 neutropenia. The most common adverse events were grade 1 and 2 myelosuppression. One patient with an oligodendroglioma had stable disease for nine cycles, and a second patient with an anaplastic pleomorphic xanthoastrocytoma achieved a sustained partial response. Immunologic analyses suggested that pomalidomide triggers immunomodulation. CONCLUSIONS: The MTD of pomalidomide is 2.6 mg/m2 . It was well tolerated, and immune correlates showed a serum immune response. These data led to an industry-sponsored phase 2 trial of pomalidomide monotherapy in children with recurrent brain tumors (NCT03257631).

General cancer screening practices among adult survivors of retinoblastoma: Results from the Retinoblastoma Survivor Study.

We assessed breast, cervical, and colorectal cancer screening practices in adult retinoblastoma (Rb) survivors and non-Rb controls. We found that most Rb survivors adhered to general population cancer screening recommendations. Rates did not differ among Rb survivors and non-Rb controls, or among survivors by laterality, even though bilateral survivors reported higher levels of concern about future health and cancer risk. Older age, being overweight/obese, and lack of recent contact with medical personnel were independently associated with decreased utilization of Pap smear among female Rb survivors. Future studies are warranted to determine whether these associations might provide an opportunity for intervention.

A phase I trial of the CDK 4/6 inhibitor palbociclib in pediatric patients with progressive brain tumors: A Pediatric Brain Tumor Consortium study (PBTC-042).

BACKGROUND: Disruption of cell-cycle regulators is a potential therapeutic target for brain tumors in children and adolescents. The aim of this study was to determine the maximum tolerated dose (MTD) and describe toxicities related to palbociclib, a selective cyclin-dependent kinase 4/6 (CDK4/6) inhibitor in pediatric patients with progressive/refractory brain tumors with intact retinoblastoma protein. METHODS: Palbociclib was administered orally starting at 50 mg/m2 daily for the first 21 days of a 28-day course. Dose escalation was according to the Rolling-6 statistical design in less heavily (stratum I) and heavily pretreated (stratum II) patients, and MTD was determined separately for each group. Pharmacokinetic studies were performed during the first course, and pharmacodynamic studies were conducted to evaluate relationships between drug levels and toxicities. RESULTS: A total of 21 patients were enrolled on stratum I and 14 patients on stratum II. The MTD for both strata was 75 mg/m2 . Palbociclib absorption (mean Tmax between 4.9 and 6.6 h) and elimination (mean half-life between 11.3 and 19.5 h) were assessed. The most common toxicity was myelosuppression. Higher palbociclib exposure was associated with grade 3/4 neutropenia and leukopenia. Dose limiting toxicities included grade 4 neutropenia and grade 3 thrombocytopenia and dehydration. No patients had an objective response to palbociclib therapy. CONCLUSIONS: Palbociclib was safely administered to children and adolescents at a dosage of 75 mg/m2 for 21 consecutive days followed by seven days of rest in both strata. Future studies will establish its optimal utilization in pediatric patients with brain tumors.

Response assessment in paediatric high-grade glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group.

Response criteria for paediatric high-grade glioma vary historically and across different cooperative groups. The Response Assessment in Neuro-Oncology working group developed response criteria for adult high-grade glioma, but these were not created to meet the unique challenges in children with the disease. The Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group, consisting of an international panel of paediatric and adult neuro-oncologists, clinicians, radiologists, radiation oncologists, and neurosurgeons, was established to address issues and unique challenges in assessing response in children with CNS tumours. We established a subcommittee to develop response assessment criteria for paediatric high-grade glioma. Current practice and literature were reviewed to identify major challenges in assessing the response of paediatric high-grade gliomas to various treatments. For areas in which scientific investigation was scarce, consensus was reached through an iterative process. RAPNO response assessment recommendations include the use of MRI of the brain and the spine, assessment of clinical status, and the use of corticosteroids or antiangiogenics. Imaging standards for brain and spine are defined. Compared with the recommendations for the management of adult high-grade glioma, for paediatrics there is inclusion of diffusion-weighted imaging and a higher reliance on T2-weighted fluid-attenuated inversion recovery. Consensus recommendations and response definitions have been established and, similar to other RAPNO recommendations, prospective validation in clinical trials is warranted.

Recommendations for Long-Term Follow-up of Adults with Heritable Retinoblastoma.

PURPOSE: To generate recommendations for long-term follow-up of adult survivors of heritable retinoblastoma. DESIGN: We convened a meeting of providers from retinoblastoma centers around the world to review the state of the science and to evaluate the published evidence. PARTICIPANTS: Retinoblastoma is a rare childhood cancer of the retina. Approximately 40% of retinoblastoma cases are heritable, resulting from a germline mutation in RB1. Dramatic improvements in treatment and supportive care have resulted in a growing adult survivor population. However, survivors of heritable retinoblastoma have a significantly increased risk of subsequent malignant neoplasms, particularly bone and soft tissue sarcomas, uterine leiomyosarcoma, melanomas, and radiotherapy-related central nervous system tumors, which are associated with excess morbidity and mortality. Despite these risks, no surveillance recommendations for this population currently are in place, and surveillance practices vary widely by center. METHODS: Following the Institute of Medicine procedure for clinical practice guideline development, a PubMed, EMBASE, and Web of Science search was performed, resulting in 139 articles; after abstract and full-text review, 37 articles underwent detailed data abstraction to quantify risk and evidence regarding surveillance, if available. During an in-person meeting, evidence was presented and discussed, resulting in consensus recommendations. MAIN OUTCOME MEASURES: Diagnosis and mortality from subsequent neoplasm. RESULTS: Although evidence for risk of subsequent neoplasm, especially sarcoma and melanoma, was significant, evidence supporting routine testing of asymptomatic survivors was not identified. Skin examination for melanoma and prompt evaluation of signs and symptoms of head and neck disease were determined to be prudent. CONCLUSIONS: This review of the literature confirmed some of the common second cancers in retinoblastoma survivors but found little evidence for a benefit from currently available surveillance for these malignancies. Future research should incorporate international partners, patients, and family members.

Pineoblastoma in children less than six years of age: The Head Start I, II, and III experience.

BACKGROUND: We report the outcomes of patients with pineoblastoma and trilateral retinoblastoma syndrome enrolled on the Head Start (HS) I-III trials. METHODS: Twenty-three children were enrolled prospectively between 1991 and 2009. Treatment included maximal surgical resection followed by five cycles of intensive chemotherapy and consolidation with marrow-ablative chemotherapy and autologous hematopoietic cell rescue (HDCx/AuHCR). Irradiation following consolidation was reserved for children over six years of age or those with residual tumor at the end of induction. RESULTS: Median age was 3.12 years (range, 0.44-5.72). Three patients withdrew from the study treatment and two patients experienced chemotherapy-related death. Eight patients experienced progressive disease (PD) during induction chemotherapy and did not proceed to HDCx/AuHCR. Ten patients received HDCx/AuHCR; eight experienced PD post-consolidation. Seven patients received craniospinal irradiation (CSI) with a median dose of 20.7 Gy (range, 18-36 Gy) with boost(s) (median dose 27 Gy; range, 18-36 Gy); three received CSI as adjuvant therapy (two post-HDCx/AuHCR) and four upon progression/recurrence. The five-year progression-free survival (PFS) and overall survival (OS) were 9.7% (95% confidence intervals [CI]: 2.6%-36.0%) and 13% (95% CI: 4.5%-37.5%), respectively. Only three patients survived beyond five years. Favorable OS prognostic factors were CSI (hazard ratio [HR] = 0.30 [0.11-0.86], P = 0.025) and HDCx/AuHCR (HR = 0.40 [0.16-0.99], P = 0.047). CONCLUSIONS: Within the HS I-III trials, CSI and HDCx/AuHCR were statistically associated with improved survival. The high PD rate during later induction cycles and following consolidation chemotherapy warrants consideration of fewer induction cycles prior to consolidation and the potential intensification of consolidation with multiple cycles of marrow-ablative chemotherapy and irradiation.

Whole-body magnetic resonance imaging as surveillance for subsequent malignancies in preadolescent, adolescent, and young adult survivors of germline retinoblastoma: An update.

BACKGROUND: Germline retinoblastoma (Rb) survivors are at lifelong risk for developing subsequent malignancies (SMNs). Optimal surveillance modalities are needed to detect SMN at an early stage in this high-risk cohort. We investigated the use of rapid whole-body magnetic resonance imaging (WB-MRI) as a noninvasive screening modality in this cohort. PROCEDURE: WB-MRI was performed in asymptomatic preadolescent, adolescent, or young adult survivors of germline Rb from February 1, 2008 to December 31, 2018 at a tertiary cancer center. We calculated sensitivity and specificity of WB-MRI and rate of false-positive findings requiring additional evaluation. RESULTS: Overall, 110 WB-MRI were performed in 47 germline Rb survivors (51% female; median age at initial WB-MRI: 15.5 years [range 8-25.3]). Patients received 1-10 annual WB-MRI examinations (median: two). Thirteen patients had an abnormal WB-MRI; three findings were deemed to be likely benign and were not evaluated further. Ten patients required dedicated imaging and three required biopsy; two patients were diagnosed with localized high-grade osteosarcoma, while the other eight had benign findings. One patient was diagnosed with secondary osteosarcoma 3 months after normal WB-MRI. In total, there were 96 true negatives, 11 false positives, two true positives, and one false negative. The sensitivity of WB-MRI in this cohort was 66.7% (95% confidence interval [CI], 14.2-96.0) and the specificity was 89.7% (95% CI, 83.6-93.7). CONCLUSIONS: Based on our 10-year experience, surveillance WB-MRI appears to have limited utility as a surveillance modality for SMN in germline Rb survivors. Alternate screening modalities should be investigated.

A Potential Role For Apparent Diffusion Coefficient in the Diagnosis of Trilateral Retinoblastoma.

We attempted to investigate the potential role for apparent diffusion coefficient (ADC) to diagnose trilateral retinoblastoma (TRb) by retrospectively reviewing brain magnetic resonance images of retinoblastoma patients. Observations: The median ADC measured 620.95 for TRb (n=6) and 1238.5 for normal pineal gland in bilateral retinoblastoma (n=8). Monitoring ADC trends aided in establishing the appropriate diagnoses in 3 patients (2 TRb, 1 benign pineal cyst). Conclusions: Our results provide baseline reference data and describe the importance of downward trending ADC which should prompt consideration of TRb. Unchanged high/nonrestricted values (>1000) may distinguish those with benign pineal tissue and obviate invasive neurosurgical procedures.

Impact of enucleation on adult retinoblastoma survivors' quality of life: A qualitative study of survivors' perspectives.

OBJECTIVES: Retinoblastoma is the most common primary intraocular tumor of childhood with >95% survival rates in the US. Traditional therapy for retinoblastoma often included enucleation (removal of the eye). While much is known about the visual, physical, and cognitive ramifications of enucleation, data are lacking about survivors' perception of how this treatment impacts overall quality of life. METHODS: Qualitative analysis of an open-ended response describing how much the removal of an eye had affected retinoblastoma survivors' lives and in what ways in free text, narrative form. RESULTS: Four hundred and four retinoblastoma survivors who had undergone enucleation (bilateral disease = 214; 52% female; mean age = 44, SD = 11) completed the survey. Survivors reported physical problems (n = 205, 50.7%), intrapersonal problems (n = 77, 19.1%), social and relational problems (n = 98, 24.3%), and affective problems (n = 34, 8.4%) at a mean of 42 years after diagnosis. Three key themes emerged from survivors' responses; specifically, they (1) continue to report physical and intrapersonal struggles with appearance and related self-consciousness due to appearance; (2) have multiple social and relational problems, with teasing and bullying being prominent problems; and (3) reported utilization of active coping strategies, including developing more acceptance and learning compensatory skills around activities of daily living. SIGNIFICANCE OF RESULTS: This study suggests that adult retinoblastoma survivors treated with enucleation continue to struggle with a unique set of psychosocial problems. Future interventions can be designed to teach survivors more active coping skills (e.g., for appearance-related issues, vision-related issues, and teasing/bullying) to optimize survivors' long-term quality of life.

Selumetinib in paediatric patients with BRAF-aberrant or neurofibromatosis type 1-associated recurrent, refractory, or progressive low-grade glioma: a multicentre, phase 2 trial.

BACKGROUND: Paediatric low-grade glioma is the most common CNS tumour of childhood. Although overall survival is good, disease often recurs. No single universally accepted treatment exists for these patients; however, standard cytotoxic chemotherapies are generally used. We aimed to assess the activity of selumetinib, a MEK1/2 inhibitor, in these patients. METHODS: The Pediatric Brain Tumor Consortium performed a multicentre, phase 2 study in patients with paediatric low-grade glioma in 11 hospitals in the USA. Patients aged 3-21 years with a Lansky or Karnofsky performance score greater than 60 and the presence of recurrent, refractory, or progressive paediatric low-grade glioma after at least one standard therapy were eligible for inclusion. Patients were assigned to six unique strata according to histology, tumour location, NF1 status, and BRAF aberration status; herein, we report the results of strata 1 and 3. Stratum 1 comprised patients with WHO grade I pilocytic astrocytoma harbouring either one of the two most common BRAF aberrations (KIAA1549-BRAF fusion or the BRAFV600E [Val600Glu] mutation). Stratum 3 comprised patients with any neurofibromatosis type 1 (NF1)-associated paediatric low-grade glioma (WHO grades I and II). Selumetinib was provided as capsules given orally at the recommended phase 2 dose of 25 mg/m2 twice daily in 28-day courses for up to 26 courses. The primary endpoint was the proportion of patients with a stratum-specific objective response (partial response or complete response), as assessed by the local site and sustained for at least 8 weeks. All responses were reviewed centrally. All eligible patients who initiated treatment were evaluable for the activity and toxicity analyses. Although the trial is ongoing in other strata, enrolment and planned follow-up is complete for strata 1 and 3. This trial is registered with ClinicalTrials.gov, number NCT01089101. FINDINGS: Between July 25, 2013, and June 12, 2015, 25 eligible and evaluable patients were accrued to stratum 1, and between Aug 28, 2013, and June 25, 2015, 25 eligible and evaluable patients were accrued to stratum 3. In stratum 1, nine (36% [95% CI 18-57]) of 25 patients achieved a sustained partial response. The median follow-up for the 11 patients who had not had a progression event by Aug 9, 2018, was 36·40 months (IQR 21·72-45·59). In stratum 3, ten (40% [21-61]) of 25 patients achieved a sustained partial response; median follow-up was 48·60 months (IQR 39·14-51·31) for the 17 patients without a progression event by Aug 9, 2018. The most frequent grade 3 or worse adverse events were elevated creatine phosphokinase (five [10%]) and maculopapular rash (five [10%]). No treatment-realted deaths were reported. INTERPRETATION: Selumetinib is active in recurrent, refractory, or progressive pilocytic astrocytoma harbouring common BRAF aberrations and NF1-associated paediatric low-grade glioma. These results show that selumetinib could be an alternative to standard chemotherapy for these subgroups of patients, and have directly led to the development of two Children's Oncology Group phase 3 studies comparing standard chemotherapy to selumetinib in patients with newly diagnosed paediatric low-grade glioma both with and without NF1. FUNDING: National Cancer Institute Cancer Therapy Evaluation Program, the American Lebanese Syrian Associated Charities, and AstraZeneca.

A multicenter study of patients with multisystem Langerhans cell histiocytosis who develop secondary hemophagocytic lymphohistiocytosis.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the presence of abnormal CD1a-positive (CD1a+ )/CD207+ histiocytes. Hemophagocytic lymphohistiocytosis (HLH) represents a spectrum of hyperinflammatory syndromes typified by the dysregulated activation of the innate and adaptive immune systems. Patients with LCH, particularly those with multisystem (MS) involvement, can develop severe hyperinflammation mimicking that observed in HLH. Nevertheless, to the authors' knowledge, little is known regarding the prevalence, timing, risk factors for development, and outcomes of children and young adults who develop HLH within the context of MS-LCH (hereafter referred to LCH-associated HLH). METHODS: To gain further insights, the authors conducted a retrospective, multicenter study and collected data regarding all patients diagnosed with MS-LCH between 2000 and 2015. RESULTS: Of 384 patients with MS-LCH, 32 were reported by their primary providers to have met the diagnostic criteria for HLH, yielding an estimated 2-year cumulative incidence of 9.3% ± 1.6%. The majority of patients developed HLH at or after the diagnosis of MS-LCH, and nearly one-third (31%) had evidence of an intercurrent infection. Patient age <2 years at the time of diagnosis of LCH; female sex; LCH involvement of the liver, spleen, and hematopoietic system; and a lack of bone involvement each were found to be independently associated with an increased risk of LCH-associated HLH. Patients with MS-LCH who met the criteria for HLH had significantly poorer 5-year survival compared with patients with MS-LCH who did not meet the criteria for HLH (69% vs 97%; P < .0001). CONCLUSIONS: Given its inferior prognosis, further efforts are warranted to enhance the recognition and optimize the treatment of patients with LCH-associated HLH.