Background: Effective treatments are still needed to reduce the severity of symptoms, time of hospitalization, and mortality of COVID-19. SARS-CoV-2 specific memory T-lymphocytes obtained from convalescent donors recovered can be used as passive cell immunotherapy. Methods: Between September and November 2020 a phase 1, dose-escalation, single centre clinical trial was conducted to evaluate the safety and feasibility of the infusion of CD45RA À memory T cells containing SARS-CoV-2 specific T cells as adoptive cell therapy against moderate/severe cases of COVID-19. Nine participants with pneumonia and/or lymphopenia and with at least one human leukocyte antigen (HLA) match with the donor were infused. The first three subjects received the lowest dose (1 £ 10 5 cells/kg), the next three received the intermediate dose (5 £ 10 5 cells/kg) and the last three received the highest dose (1 £ 10 6 cells/ kg) of CD45RA À memory T cells. Clinicaltrials.gov registration: NCT04578210. Findings: All participants' clinical status measured by National Early Warning Score (NEWS) and 7-category point ordinal scales showed improvement six days after infusion. No serious adverse events were reported. Inflammatory parameters were stabilised post-infusion and the participants showed lymphocyte recovery two weeks after the procedure. Donor microchimerism was observed at least for three weeks after infusion in all patients. Interpretation: This study provides preliminary evidence supporting the idea that treatment of COVID-19 patients with moderate/severe symptoms using convalescent CD45RA À memory T cells is feasible and safe. Funding: Clinical Trial supported by Spanish Clinical Research Network PT17/0017/0013. Co-funded by European Regional Development Fund/European Social Fund. CRIS CANCER Foundation Grant to AP-M and Agencia Valenciana de Innovaci on Grant AVI-GVA COVID-19-68 to BS.

Limited information is available regarding SARS-CoV-2 infections in children with underlying diseases. A retrospective study of children less than 15 years old with primary or secondary immunosuppression infected with SARS-CoV-2 during March 2020 was performed. In this series, 8 immunocompromised patients with COVID-19 disease are reported, accounting for 15% of the positive cases detected in children in a reference hospital. The severity of the symptoms was mild-moderate in the majority with a predominance of febrile syndrome, with mild radiological involvement and in some cases with mild respiratory distress that required oxygen therapy. The rational and prudent management of these patients is discussed, evaluating possible treatments and options for hospitalization or outpatient follow-up. Conclusion: In our experience, monitoring of children with immunosuppression and COVID-19 disease can be performed as outpatients if close monitoring is possible. Hospitalization should be assessed when high fever, radiological involvement, and/or respiratory distress are present. What is Known: • SARS-CoV-2 infection is usually mild in children. What is New: • Outcome of immunosuppressed children with COVID-19 is generally good, with a mild-moderate course.

Introduction Data regarding real-world impact on cancer clinical research during COVID-19 are scarce. We analysed the impact of the COVID-19 pandemic on the conduct of paediatric cancer phase I-II trials in Europe through the experience of the Innovative Therapies for Children with Cancer (ITCC). Methods A survey was sent to all ITCC-accredited Early-Phase Clinical Trial Hospitals including questions about impact on staff activities, recruitment, patient care, supply of investigational products and legal aspects, between 1/March and 30/April/2020. Results Thirty-one out of 53 hospitals from 12 countries participated. Challenges reported included staff constraints (30% drop), reduction in planned monitoring activity (67% drop of site initiation visits and 64% of monitoring visits) and patient recruitment (61% drop compared to 2019). The percentage of phase I, phase II trials and molecular platforms closing to recruitment in at least one site was 48.5%, 61.3% and 64.3%, respectively. Additionally, 26% of sites had restrictions on performing trial assessments due to local contingency plans. Almost half of the units suffered impact upon pending contracts. Most hospitals (65%) are planning on improving organizational and structural changes. Conclusion The study reveals a profound disruption of paediatric cancer early phase clinical research due to the COVID-19 pandemic across Europe. Reported difficulties affected both patient care and monitoring activity. Efforts should be made to reallocate resources to avoid lost opportunities for patients and to allow the continued advancement of oncology research. Identified adaptations to clinical trial procedures may be integrated to increase preparedness of clinical research to futures crises.

IntroductionLynch syndrome (LS) and constitutional mismatch repair deficiency (CMMRD) are hereditary cancer syndromes associated with mismatch repair (MMR) deficiency. Tumours show microsatellite instability (MSI), also reported at low levels in non-neoplastic tissues. Our aim was to evaluate the performance of high-sensitivity MSI (hs-MSI) assessment for the identification of LS and CMMRD in non-neoplastic tissues.Materials and methodsBlood DNA samples from 131 individuals were grouped into three cohorts: baseline (22 controls), training (11 CMMRD, 48 LS and 15 controls) and validation (18 CMMRD and 18 controls). Custom next generation sequencing panel and bioinformatics pipeline were used to detect insertions and deletions in microsatellite markers. An hs-MSI score was calculated representing the percentage of unstable markers.ResultsThe hs-MSI score was significantly higher in CMMRD blood samples when compared with controls in the training cohort (p<0.001). This finding was confirmed in the validation set, reaching 100% specificity and sensitivity. Higher hs-MSI scores were detected in biallelic MSH2 carriers (n=5) compared with MSH6 carriers (n=15). The hs-MSI analysis did not detect a difference between LS and control blood samples (p=0.564).ConclusionsThe hs-MSI approach is a valuable tool for CMMRD diagnosis, especially in suspected patients harbouring MMR variants of unknown significance or non-detected biallelic germline mutations.

Purpose The COVID-19 pandemic has forced healthcare stakeholders towards challenging decisions. We analyse the impact of the pandemic on the conduct of phase I-II trials for paediatric cancer during the first month of state of alarm in Spain. Methods A questionnaire was sent to all five ITCC-accredited Spanish Paediatric Oncology Early Phase Clinical Trial Units, including questions about impact on staff activities, recruitment, patient care, supply of investigational products, and legal aspects. Results All units suffered personnel shortages and difficulties in enrolling patients, treatment continuity, or performing trial assessments. Monitoring activity was frequently postponed (73%), and 49% of ongoing trials interrupted recruitment. Only two patients could be recruited during this period (75% reduction in the expected rate). Conclusions The COVID-19 crisis has significantly impacted clinical research practice and access to innovation for children with cancer. Structural and functional changes are under way to better cope with the expected future restrictions.