A phase I/II study of adoptive SARS-CoV-2-specific T cells in immunocompromised hosts with or at risk of severe COVID-19 infection.

BACKGROUND: Post-transplant or hematological cancer patients have a higher risk of mortality after infection with ancestral and early variants of severe acute respiratory syndrome (SARS)-CoV-2. Adoptive cell therapy (ACT) with virus-specific T cells (VSTs) could augment endogenous T cell immunity to avoid disease deterioration before viral clearance. METHODS: We established a third-party SARS-CoV-2-specific T cell (COVID-T) bank in 2020 (NCT04351659) using convalescent and/or vaccinated donors. In a phase I/II study (NCT04457726), 13 adult and pediatric patients, acutely positive for SARS-CoV-2 and predicted to have a high chance of mortality, were recruited from September 2021 to February 2022. Twelve patients received a single dose of COVID-T cells, matched on at least 1 HLA. RESULTS: A dose of either 75,000 or 150,000 IFN-γ+CD3+ cells/m2 SARS-COV-2-specific T cells did not cause cytokine release syndrome, acute respiratory distress syndrome, or graft-versus-host disease. In the 8 patients who had detectable donor SARS-COV-2-specific T cells after ACT, none progressed to severe disease or died with COVID-19. In contrast, among the other four patients without evidence of donor micro-chimerism, two died of COVID-19. CONCLUSIONS: Long-acting third-party VSTs from convalescent or vaccinated donors could be expediently produced and might be clinically useful in future pandemics, particularly before global vaccination is implemented.

Larotrectinib followed by selitrectinib in a novel DCTN1-NTRK1 fusion undifferentiated pleomorphic sarcoma.

INTRODUCTION: Neurotrophic receptor tyrosine kinase fusions cause overexpression or activation of kinase and are believed to confer oncogenic potential in some non-rhabdomyosarcoma soft tissue sarcomas. TRK inhibitors have recently been shown to induce responses in these tumours though current experience with these agents is still limited. CASE REPORT: We report a case of an adolescent with treatment-refractory non-rhabdomyosarcoma soft tissue sarcomas, carrying a novel DCTN1-NTRK1 gene fusion whose progressive disease was treated with multi-kinase and TRK inhibitors.Management and outcome: Our patient was started on pan-TRK inhibitor larotrectinib, as his disease progressed after chemotherapy, radiation therapy and surgery, based on next-generation sequencing test showing DCTN1-NTRK1 gene fusion. He responded quickly to larotrectinib with the improvement of symptoms and reduction of masses. However, this response was short-lived due to the development of acquired solvent front resistance mutation. This patient did not respond to next-generation TRK inhibitor selitrectinib and eventually succumbed to his disease. DISCUSSION: The initial rapid and drastic response of our patient to larotrectinib was not sustained due to the development of acquired resistance. This case emphasizes the need for upfront and periodic next-generation sequencing testing to guide treatment of patients with refractory non-rhabdomyosarcoma soft tissue sarcomas.

Adolescent with facial swelling.

BackgroundA previously well 15-year-old girl presented with a 2-month history of facial swelling that progressively worsened to involve the neck. There was associated dyspnoea, orthopnoea, headache and throat discomfort. Two weeks before presentation, the patient had an episode of fever for 5 days. On examination, vital signs were within normal limits. Swelling, plethora and venous distension of the face and neck were apparent (figure 1).

Neuroblastoma patient-derived cultures are enriched for a mesenchymal gene signature and reflect individual drug response.

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient-derived cell cultures (PDCs) from chemo-naïve and post-treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo-response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal-type gene expression signature and showed upregulation of pro-angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard-of-care cytotoxics at human Cmax -equivalent concentrations, MYCN-amplified and non-MYCN-amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients' responses, and correlated with gene signatures of chemosensitivity. In this translational proof-of-concept study, early-phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug-response testing.

Successful treatment of a metastatic hepatocellular malignant neoplasm, not otherwise specified with chemotherapy and liver transplantation.

Hepatocellular malignant neoplasm, not otherwise specified (HCN-NOS) is a provisional entity describing a subset of rare malignant pediatric liver tumors with overlapping features of hepatoblastoma and hepatocellular carcinoma. We present a case illustration of metastatic HCN-NOS successfully treated with a backbone of hepatoblastoma chemotherapy, pulmonary metastastectomy, and liver transplantation, along with a literature review of the clinical outcomes of HCN.

A high-density microfluidic bioreactor for the automated manufacturing of CAR T cells.

The manufacturing of autologous chimaeric antigen receptor (CAR) T cells largely relies either on fed-batch and manual processes that often lack environmental monitoring and control or on bioreactors that cannot be easily scaled out to meet patient demands. Here we show that human primary T cells can be activated, transduced and expanded to high densities in a 2 ml automated closed-system microfluidic bioreactor to produce viable anti-CD19 CAR T cells (specifically, more than 60 million CAR T cells from donor cells derived from patients with lymphoma and more than 200 million CAR T cells from healthy donors). The in vitro secretion of cytokines, the short-term cytotoxic activity and the long-term persistence and proliferation of the cell products, as well as their in vivo anti-leukaemic activity, were comparable to those of T cells produced in a gas-permeable well. The manufacturing-process intensification enabled by the miniaturized perfusable bioreactor may facilitate the analysis of the growth and metabolic states of CAR T cells during ex vivo culture, the high-throughput optimization of cell-manufacturing processes and the scale out of cell-therapy manufacturing.

A Review of CAR-T Therapy in Pediatric and Young Adult B-Lineage Acute Leukemia: Clinical Perspectives in Singapore.

Approximately 10-15% of pediatric B-cell acute lymphoblastic leukemia (B-ALL) are high risk at diagnosis or relapsed/ refractory. Prior to the availability of chimeric antigen receptor T-cell (CAR-T) in Singapore and the region, the treatment options for these paediatric and young adults are conventional salvage chemotherapy or chemo-immunotherapy regimens as a bridge to allogeneic total body irradiation-based hematopoietic stem cell transplantation (allo-HSCT). This results in significant acute and long-term toxicities, with suboptimal survival outcomes. Finding a curative salvage therapy with fewer long-term toxicities would translate to improved quality-adjusted life years in these children and young adults. In this review, we focus on the burden of relapsed/refractory pediatric B-ALL, the limitations of current strategies, the emerging paradigms for the role of CAR-T in r/r B-ALL, our local perspectives on the health economics and future direction of CAR-T therapies in pediatric patients.

Exploiting frequent and specific expression of PRL3 in pediatric solid tumors for first-in-child use of PRL3-zumab humanized antibody.

Phosphatase of regenerating liver 3 (PRL3) is a specific tumor antigen overexpressed in a broad range of adult cancer types. However, its physiological expression in pediatric embryonal and mesenchymal tumors and its association with clinical outcomes in children is unknown. We sought to profile the expression of PRL3 in pediatric tumors in relation to survival outcomes, expression of angiogenesis markers, and G-protein-coupled receptor (GPCR)-mitogen-activated protein kinase (MAPK) signaling targets. PRL3-zumab, a first-in-class humanized antibody, was administered in a dose escalation schedule in a first-in-child clinical trial to study toxicity, pharmacokinetics, and clinical outcomes. Among 64 pediatric tumors, PRL3 was most frequently expressed in neuroblastoma (100%), rhabdomyosarcoma and non-rhabdomyosarcoma soft tissue sarcomas (71%), and renal sarcomas (60%) but absent in paired normal tissues. PRL3 was expressed in 75% of relapsed tumors and associated with shorter median event-free survival. Microarray profiling of PRL3-positive tumors showed elevation of angiogenin, TIMP1 and TIMP2, and GPCR-MAPK signaling proteins that commonly interacted with PRL3. The first use of PRL3-zumab in a pediatric patient saw no adverse events. A 28.6% reduction in maximum target lesion diameter was achieved when PRL3-zumab was administered concurrently with hypofractionated radiation. These findings support wider exploration of PRL3 expression in embryonal and mesenchymal tumors and further clinical application of PRL3-zumab in pediatric patients.

Implementation of Universal Newborn Screening for Severe Combined Immunodeficiency in Singapore While Continuing Routine Bacille-Calmette-Guerin Vaccination Given at Birth.

Introduction: Severe Combined Immunodeficiency (SCID) is generally fatal if untreated; it predisposes to severe infections, including disseminated Bacille-Calmette-Guerin (BCG) disease from BCG vaccination at birth. However, delaying BCG vaccination can be detrimental to the population in tuberculosis-endemic regions. Early diagnosis of SCID through newborn screening followed by pre-emptive treatment with anti-mycobacterial therapy may be an alternative strategy to delaying routine BCG vaccination. We report the results of the first year of newborn SCID screening in Singapore while continuing routine BCG vaccination at birth. Method: Newborn screening using a T-cell receptor excision circle (TREC) assay was performed in dried blood spots received between 10 October 2019 to 9 October 2020 using the Enlite Neonatal TREC kit. Patients with low TREC had lymphocyte subset analysis and full blood count performed to determine the severity of lymphopenia and likelihood of SCID to guide further management. Results: Of the 35888 newborns screened in 1 year, no SCID cases were detected, while 13 cases of non-SCID T-cell lymphopenia (TCL) were picked up. Using a threshold for normal TREC to be >18 copies/µL, the retest rate was 0.1% and referral rate to immunologist was 0.04%. Initial low TREC correlated with low absolute lymphocyte counts (ALC), and subsequent normal ALC corresponded with increases in TREC, thus patients with normal first CD3+ T cell counts were considered to have transient idiopathic TCL instead of false positive results. 7/13 (54%) had secondary TCL (from sepsis, Trisomy 21 with hydrops and stoma losses or chylothorax, extreme prematurity, or partial DiGeorge Syndrome) and 6/13 (46%) had idiopathic TCL. No cases of SCID were diagnosed clinically in Singapore during this period and for 10 months after, indicating that no cases were missed by the screening program. 8/9 (89%) of term infants with abnormal TREC results received BCG vaccination within the first 6 days of life when TREC and ALC were low. No patients developed BCG complications after a median follow-up of 17 months. Conclusion: Newborn screening for SCID can be implemented while continuing routine BCG vaccination at birth. Patients with transient TCL and no underlying primary immunodeficiency are able to tolerate BCG vaccination.

Rapid production of clinical-grade SARS-CoV-2 specific T cells.

Objectives: To determine whether the frequencies of SARS-CoV-2-specific T cells are sufficiently high in the blood of convalescent donors and whether it is technically feasible to manufacture clinical-grade products overnight for T-cell therapy and assessment of COVID-19 immunity. Methods: One unit of whole blood or leukapheresis was collected from each donor following standard blood bank practices. The leukocytes were stimulated using overlapping peptides of SARS-CoV-2, covering the immunodominant sequence domains of the S protein and the complete sequence of the N and M proteins. Thereafter, functionally reactive cells were enriched overnight using an automated device capturing IFNγ-secreting cells. Results: From 1 × 109 leukocytes, a median of 0.98 × 106 (range 0.56-2.95) IFNγ + T cells were produced from each of the six donors, suggesting a high frequency of SARS-CoV-2 reactive T cells in their blood, even though only one donor had severe COVID-19 requiring mechanical ventilation whereas the other five donors had minor symptoms. A median of 57% of the enriched T cells were IFNγ+ (range 20%-74%), with preferential enrichment of CD56+ T cells and effector memory T cells. TCRVß-spectratyping confirmed distinctively tall oligoclonal peaks in final products. With just six donors, the probability that a recipient would share at least one HLA allele with one of the donors is >88% among Caucasian, >95% among Chinese, >97% among Malay, and >99% among Indian populations. Conclusions: High frequencies of rapid antigen-reactive T cells were found in convalescent donors, regardless of severity of COVID-19. The feasibility of clinical-grade production of SARS-CoV-2-specific T cells overnight for therapeutics and diagnostics is revealed.

Clinical relevance of screening checklists for detecting cancer predisposition syndromes in Asian childhood tumours.

Assessment of cancer predisposition syndromes (CPS) in childhood tumours is challenging to paediatric oncologists due to inconsistent recognizable clinical phenotypes and family histories, especially in cohorts with unknown prevalence of germline mutations. Screening checklists were developed to facilitate CPS detection in paediatric patients; however, their clinical value have yet been validated. Our study aims to assess the utility of clinical screening checklists validated by genetic sequencing in an Asian cohort of childhood tumours. We evaluated 102 patients under age 18 years recruited over a period of 31 months. Patient records were reviewed against two published checklists and germline mutations in 100 cancer-associated genes were profiled through a combination of whole-exome sequencing and multiplex ligation-dependent probe amplification on blood-derived genomic DNA. Pathogenic germline mutations were identified in ten (10%) patients across six known cancer predisposition genes: TP53, DICER1, NF1, FH, SDHD and VHL. Fifty-four (53%) patients screened positive on both checklists, including all ten pathogenic germline carriers. TP53 was most frequently mutated, affecting five children with adrenocortical carcinoma, sarcomas and diffuse astrocytoma. Disparity in prevalence of germline mutations across tumour types suggested variable genetic susceptibility and implied potential contribution of novel susceptibility genes. Only five (50%) children with pathogenic germline mutations had a family history of cancer. We conclude that CPS screening checklists are adequately sensitive to detect at-risk children and are relevant for clinical application. In addition, our study showed that 10% of Asian paediatric solid tumours have a heritable component, consistent with other populations.

Advances in paediatric cancer treatment.

Four out of five children diagnosed with cancer can be cured with contemporary cancer therapy. This represents a dramatic improvement since 50 years ago when the cure rate of childhood cancer was <25% in the pre-chemotherapy era. Over the past ten years, while improvement in overall survival (OS) has been marginal, progress in pediatric oncology lies with adopting risk-adapted therapeutic approach. This has been made possible through identifying clinical and biologic prognostic factors with rigorous research and stratifying patients using these risk factors, and subsequently modifying therapy according to risk group assignment. This review provides a perspective for eight distinct pediatric malignancies, in which significant advances in treatment were made in the last decade and are leading to changes in standard of care. This includes four hematologic malignancies [acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL)] and four solid tumors [medulloblastoma (MB), low grade glioma (LGG), neuroblastoma (NB) and Ewing sarcoma (ES)]. Together, they comprise 60% of childhood cancer. Improved patient outcome is not limited to better survival, but encompasses reducing both short and long-term treatment-related complications which is as important as cure, given the majority of childhood cancer patients will become long-term survivors. Risk-adapted approach allows treatment intensification in the high-risk cohort while therapy can be de-escalated in the low-risk to minimize toxicity and late sequelae without compromising survival. Advances in medical research technology have also led to a rapid increase in the understanding of the genetics of childhood cancer in the last decade, facilitating identification of molecular targets that can potentially be exploited for therapeutic benefits. As we move into the era of targeted therapeutics, searching for novel agents that target specific genetic lesions becomes a major research focus. We provide an overview of seven novel agents (bevacizumab, bortezomib, vorinostat, sorafenib, tipifarnib, erlotinib and mTOR inhibitors), which have been most frequently pursued in childhood cancers in the last decade, as well as reporting the progress of clinical trials involving these agents.