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The urgent need for safe and effective treatments for COVID-19 has fueled the launch of many parallel complex studies of cellular therapies with small to modest enrolment projections. By pooling data from multiple studies that are similar, we can increase the ability to achieve sufficient power to determine effectiveness more quickly through meta-analysis. A scoping review of registered clinical trials using cell-based interventions for COVID-19 was conducted to identify candidate studies for meta-analysis that could support an accelerated regulatory review. ClinicalTrials.gov and WHO International Clinical Trials Registry Platform were searched April 23, 2020. Trials were included if they utilized cell or cell-derived products to treat or prevent COVID-19. Fifty-four registered cellular therapy trials were identified and included for analysis. Studies of mesenchymal stromal cells (MSCs; 41 studies; 1129 subjects projected to receive cells) and natural killer (NK) cells (5 studies; 135 projected to received cells) were observed most commonly. A subset of studies are controlled (34 studies, or 63%), including 27 studies of MSCs and 3 of NK cells. While heterogeneity in study design exists, the cumulative projected enrolment of patients from similar studies appears sufficient to allow the detection of meaningful differences in clinically important outcomes such as mortality, admission to intensive care and need for mechanical ventilation by September 2020—sooner than any individual study could determine effectiveness. MSCs are the predominant cell type in registered trials for severe or critical COVID-19 and represent the most promising candidates for future meta-analysis. Sufficient pooled sample size to detect clinically important reductions in multiple outcomes, including mortality, is anticipated by September 2020, but may require accessing supplementary data to align outcome reporting. Regulatory approval, funding and implementation by cell manufacturing partners will be accelerated by our framework for rapid meta-analysis. • Effective therapies are lacking for severe and critical COVID-19. • Many registered cell-based clinical trials are expected to be completed in 2020. • Pooling of data from similar controlled trials in real-time meta-analysis is feasible. • A framework for accelerated evidence synthesis could expedite treatment approval. [ABSTRACT FROM AUTHOR]

Background: Despite advances in treatment, acute myocardial infarction (MI) is still associated with significant morbidity and mortality, especially in patients with extensive damage and scar formation. Based on some promising preclinical studies, there is interest in the use of mesenchymal stromal cells (MSCs) to promote cardiac repair after acute MI. However, there is a need for a systematic review of this evidence to summarize the efficacy and safety of MSCs in preclinical models of MI. This will better inform the translation of MSC therapy for acute MI and guide the design of a future clinical trial. Methods/design: A systematic literature search of MEDLINE, Embase, and BIOSIS Previews will be conducted. We will identify comparative preclinical studies (randomized and non-randomized) of myocardial infarction that include animals given MSC therapy versus a vehicle/placebo. The primary outcome will be left ventricular ejection fraction. Secondary and tertiary outcomes will include death, infarct size, measures of cardiac function, biochemical outcomes, and MSC retention and differentiation. Risk of bias will be assessed using the Cochrane Risk of Bias Tool. Subgroup analyses will be performed to measure how various sources of preclinical study heterogeneity affect the direction and magnitude of the primary outcome. We will meta-analyze data using inverse variance random effects modeling. Discussion: This systematic review of preclinical evidence will provide a summary of the efficacy and safety of MSCs in animal models of MI. The results will help determine whether sufficient evidence exists to conduct a clinical trial in humans and inform its design. [ABSTRACT FROM AUTHOR]

Evidence regarding the extent that mesenchymal stromal cells (MSCs) may improve clinical outcomes in patients with coronavirus disease 2019 (COVID-19) has been limited by marked inter-study heterogeneity, inconsistent product characterization and appreciable risk of bias (RoB). Given the evolution of treatment options and trajectory of the pandemic, an updated analysis of high-quality evidence from randomized controlled trials is needed for a timely and conclusive understanding of the effectiveness of MSCs. A systematic literature search through March 30, 2022, identified all English language, full-text randomized controlled trials examining the use of MSCs in the treatment of COVID-19. Eight studies were identified (316 patients, 165 administered MSCs and 151 controls). Controls evolved significantly over time with a broad range of comparison treatments. All studies reported mortality at study endpoint. Random effects meta-analysis revealed that MSCs decreased relative risk of death (risk ratio, 0.63, 95% confidence interval, 0.42–0.94, P = 0.02, I2 = 14%) with no significant difference in absolute risk of death. MSCs decreased length of hospital stay and C-reactive protein levels and increased odds of clinical improvement at study endpoint compared with controls. Rates of adverse events and severe adverse events were similar between MSC and control groups. Only two (25%) studies reported all four International Society for Cell & Gene Therapy criteria for MSC characterization. Included studies had low (n = 7) or some (n = 1) concerns regarding RoB. MSCs may reduce risk of death in patients with severe or critical COVID-19 and improve secondary clinical outcomes. Variable outcome reporting, inconsistent product characterization and variable control group treatments remain barriers to higher-quality evidence and may constrain clinical usage. A master protocol is proposed and appears necessary for accelerated translation of higher-quality evidence for future applications of MSC therapy. Forest plot demonstrating significantly decreased relative risk of death at study endpoint in patients administered MSCs (experimental) compared with patients not administered MSCs (control). Control groups received standard of care for COVID-19 at the time of hospital admission, which varied depending on the institution. [Display omitted] [ABSTRACT FROM AUTHOR]

Mesenchymal stem/stromal cells (MSCs) and their secreted products are a promising therapy for COVID-19 given their immunomodulatory and tissue repair capabilities. Many small studies were launched at the onset of the pandemic, and repeated meta-analysis is critical to obtain timely and sufficient statistical power to determine efficacy. All English-language published studies identified in our systematic search (up to February 3, 2021) examining the use of MSC-derived products to treat patients with COVID-19 were identified. Risk of bias (RoB) was assessed for all studies. Nine studies were identified (189 patients), four of which were controlled (93 patients). Three of the controlled studies reported on mortality (primary analysis) and were pooled through random-effects meta-analysis. MSCs decreased the risk of death at study endpoint compared with controls (risk ratio, 0.18; 95% confidence interval [CI], 0.04 to 0.74; P =.02; I 2 = 0%), although follow-up differed. Among secondary outcomes, interleukin-6 levels were most commonly reported and were decreased compared with controls (standardized mean difference, –0.69; 95% CI, –1.15 to –0.22; P =.004; I 2 = 0%) (n = 3 studies). Other outcomes were not reported consistently, and pooled estimates of effect were not performed. Substantial heterogeneity was observed between studies in terms of study design. Adherence to published ISCT criteria for MSC characterization was low. In two of nine studies, RoB analysis revealed a low to moderate risk of bias in controlled studies, and uncontrolled case series were of good (3 studies) or fair (2 studies) quality. Use of MSCs to treat COVID-19 appears promising; however, few studies were identified, and potential risk of bias was detected in all studies. More controlled studies that report uniform clinical outcomes and use MSC products that meet standard ISCT criteria should be performed. Future iterations of our systematic search should refine estimates of efficacy and clarify potential adverse effects. [ABSTRACT FROM AUTHOR]