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ABSTRACTWe evaluated the immunogenicity of 300 mg Tixagevimab-Cilgavimab in immunocompromised children and adolescents who weighed 20 to >40 kg. Six to 18-year-old participants were divided into two groups by body weight and received 300 mg (20 to <40 kg) and 600 mg (≥40 kg) Tixagevimab-Cilgavimab, respectively. Anti-SARS-CoV-2 receptor-binding domain IgG concentrations and pseudovirus neutralizing antibody (NAb) titers were measured at 4, 12, and 24 weeks after administration and compared with reference data from healthy Thai children at 2 weeks after three BNT162b2 vaccinations. Of 59 participants, 49.2% were female, with a median (IQR) age of 12 (9, 15) years; 16 (27.1%) had cancer. NAb titers (95% CI) for the ancestral Wuhan strain were comparatively high for both dosing regimens (16363.2 [13765.9, 19450.5] vs 17768.3 [15539.5, 20316.9] in 20 to <40 kg and ≥40 kg participants, respectively) and significantly higher than reference titers (P < 0.001 for both). NAb titers for Omicron BA.4/5 were on par with the reference for both dosing regimens. Adverse events were mild, well tolerated, and slightly more prevalent in ≥40 kg participants who received full-dose Tixagevimab–Cilgavimab. Minimal waning in anti-RBD IgG concentrations, comparable to the reference, was observed at 12 and 24 weeks after Tixagevimab-Cilgavimab administration for both regimens. We concluded that half-dose Tixagevimab-Cilgavimab in 20 to <40 kg participants generated equivalent antibodies to standard doses in ≥40 kg participants and significantly higher antibodies than three-dose BNT162b2 vaccination. Further study of monoclonal long-acting antibodies in larger cohorts and <6-year-old children are warranted.

In patients with non-transfusion-dependent β-thalassaemia, haemoglobin concentrations lower than 10 g/dL are associated with a higher risk of morbidity, mortality, and impaired quality of life. No drugs are specifically approved for anaemia management in patients with non-transfusion-dependent β-thalassaemia, other than transfusion therapy administered infrequently in accordance with patients’ needs. We assessed the efficacy and safety of luspatercept versus placebo in patients with non-transfusion-dependent β-thalassaemia.

IMPORTANCE: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child’s life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. OBJECTIVES: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. DESIGN, SETTING, AND PARTICIPANTS: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. MAIN OUTCOMES AND MEASURES: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. RESULTS: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle–income countries and HICs, 17.92 [95% CI, 12.94-24.80], and for lower-middle–income countries vs upper-middle–income countries and HICs, 5.74 [95% CI, 4.30-7.68]). CONCLUSIONS AND RELEVANCE: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs.

Supplemental Digital Content is available in the text.Mediastinal germ cell tumor (MGCT), which accounts for 1% to 3% of extragonadal germ cell tumors, has unique manifestations; it is associated with several types of hematologic malignancy, particularly myeloid neoplasm. The aim of this study was to report the 10-year incidence, clinical characteristics, and outcomes of MGCT at Thailand’s national pediatric tertiary referral center. This retrospective study included patients diagnosed with MGCT at the Department of Pediatrics, Siriraj Hospital during 2005 to 2014. Eight patients (all male) were diagnosed with MGCT. Five of 8 patients were found to have hematologic abnormalities. Three patients were diagnosed with acute myeloid leukemia (AML) (one patient with M1, another having M7, and the other with M0). Another patient had mixed MGCT with mediastinal myeloid sarcoma (MMS). The other patient had malignancy-associated hemophagocytic lymphohistiocytosis syndrome (M-HLH). Isochromosome 12p was detected in 3 patients (AML [2], mixed MGCT/MMS [1]). Four of 5 patients with hematologic abnormalities died of hematologic abnormalities or treatment complication (AML [3], M-HLH [1]). One patient with mixed MGCT/MMS survived with chemotherapy. All patients with AML and MMS were nonseminomatous MGCT and the onset of myeloid malignancies were within 1 year after the diagnosis of MGCT. Associated hematologic malignancies should be suspected in MGCT with abnormal blood count or hematologic symptoms. Isochromosome 12p was the most common cytogenetic finding in MGCT-associated myeloid malignancies patients. Those with nonseminomatous MGCT should have their blood count carefully monitored especially during the first year after the diagnosis of MGCT. Better treatment alternatives for MGCT with associated hematologic malignancies are warranted to ameliorate adverse outcomes.

FLT3 kinase internal tandem duplication (ITD) mutations are common in acute myeloid leukemia (AML) and are associated with poor clinical outcomes. Although initial responses to FLT3 tyrosine kinase inhibitors (TKIs) are observed in FLT3-ITD−positive patients, subsequent relapse often occurs upon acquisition of secondary FLT3 kinase domain (KD) mutations, primarily at residues D835 and F691. Using biochemical assays, we determined that crenolanib, a novel TKI, demonstrates type I properties and is active against FLT3 containing ITD and/or D835- or F691-activating mutations. Potent activity was observed in FLT3-ITD−positive AML cell lines. Crenolanib delayed the outgrowth of MV4-11 cells in a xenograft mouse model, whereas in combination with the type II TKI sorafenib, a significant decrease in leukemic burden (P < .001) and prolonged survival (P < .01) was observed compared with either type I or II TKI alone. Crenolanib was active against Ba/F3 cells harboring FLT3-ITD and secondary KD mutations and sorafenib-resistant MOLM-13 cells containing FLT3-ITD/D835Y both in vitro and in vivo. In addition, crenolanib inhibited drug-resistant AML primary blasts with FLT3-ITD and D835H/Y mutations. These preclinical data demonstrate that crenolanib is effective against FLT3-ITD containing secondary KD mutations, suggesting that crenolanib may be a useful therapeutic agent for TKI-naive and drug-resistant FLT3-ITD−positive AML.

FLT3 kinase internal tandem duplication (ITD) mutations are common in acute myeloid leukemia (AML) and are associated with poor clinical outcomes. Although initial responses to FLT3 tyrosine kinase inhibitors (TKIs) are observed in FLT3-ITD−positive patients, subsequent relapse often occurs upon acquisition of secondary FLT3 kinase domain (KD) mutations, primarily at residues D835 and F691. Using biochemical assays, we determined that crenolanib, a novel TKI, demonstrates type I properties and is active against FLT3 containing ITD and/or D835- or F691-activating mutations. Potent activity was observed in FLT3-ITD−positive AML cell lines. Crenolanib delayed the outgrowth of MV4-11 cells in a xenograft mouse model, whereas in combination with the type II TKI sorafenib, a significant decrease in leukemic burden (P< .001) and prolonged survival (P< .01) was observed compared with either type I or II TKI alone. Crenolanib was active against Ba/F3 cells harboring FLT3-ITD and secondary KD mutations and sorafenib-resistant MOLM-13 cells containing FLT3-ITD/D835Y both in vitro and in vivo. In addition, crenolanib inhibited drug-resistant AML primary blasts with FLT3-ITD and D835H/Y mutations. These preclinical data demonstrate that crenolanib is effective against FLT3-ITD containing secondary KD mutations, suggesting that crenolanib may be a useful therapeutic agent for TKI-naive and drug-resistant FLT3-ITD−positive AML.

Introduced in 1988 by Kaneko and colleagues, selective ophthalmic arterial infusion of chemotherapeutic drug has recently gained more interest among retinoblastoma experts worldwide. The report showed that the procedure could be repeated up to 12 treatments without serious side effects. We report a 4-year-old girl with bilateral retinoblastoma. The left eye was enucleated for the group E disease. The right eye started with 3 retinal tumors (group C) was treated with systemic chemotherapy plus local therapy. Seven months after the last cycle of chemotherapy, the tumor recurred close to the fovea. Systemic chemotherapy was reinitiated without success. To avoid aggressive cryotherapy and external-beam radiotherapy, selective ophthalmic arterial infusion of chemotherapeutic drugs was performed for 15 sessions. The tumor responded partially without evidence of drug-induced retinal toxicity by the electroretinogram. Minor irregularities of the inner wall of supraclinoid portion of the internal carotid artery were observed only at the sixth session. Narrowing of the vascular lumen occurred on the last 2 sessions. We demonstrate that this technique when performed repeatedly could result in the anatomic changes of the small blood vessel. Careful follow-up is necessary for early detection of any serious consequences.

•This is the first report on targeted T cell therapy against retinoblastoma (RB).•A novel GD2-specific CAR T with safety switch effectively killed RB.•Repetitive antigen exposure, the tumor cells gradually lost GD2 expression and increased PD-L1 expression.•The first report on RB tumor evolvement after targeted T cell therapy.

Siritanaratkul: Novartis: Research Funding; Jansen-Cilag: Research Funding; Roche: Research Funding; Pfizer: Research Funding. Wood:Celgene: Consultancy; AMAG: Consultancy; Ionis Pharmaceuticals: Consultancy; Ionis Pharmaceuticals: Consultancy; World Care Clinical: Consultancy; Biomed Informatics: Consultancy; Vifor: Consultancy; Apopharma: Consultancy; Biomed Informatics: Consultancy; Vifor: Consultancy; Apopharma: Consultancy; World Care Clinical: Consultancy; AMAG: Consultancy; Celgene: Consultancy. Viprakasit:Agios: Consultancy; Mersanger: Consultancy; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene Corporation: Consultancy, Research Funding; Faculty of Medicine, Siriraj Hospital, Mahidol University: Employment; Shire: Research Funding.