Incidence of second primary malignancies in patients with multiple myeloma receiving anti-CD38 monoclonal antibodies: A systematic review and meta-analysis.

Anti-CD38 monoclonal antibodies (mAbs) are commonly used for treating newly diagnosed and relapsed/refractory (r/r) multiple myeloma (MM). However, concerns have been raised about the occurrence of second primary malignancies (SPMs) in patients receiving anti-CD38 mAbs. Assessing the safety data for rare adverse events like SPMs is challenging because individual clinical trials are typically focused on the primary endpoint. Therefore, we conducted a meta-analysis of randomized controlled trials (RCTs) published between January 2005 and April 2022, including patients with newly diagnosed or r/r MM. Our aim was to compare SPM rate with the use of anti-CD38 mAb-based regimens with other anti-myeloma regimens. After a median follow-up of 35.3 months (range: 8.2-56.2), we found that exposure to anti-CD38 mAbs was associated with an increased risk of developing SPMs compared to the control group (6.8% vs. 5.2%; Peto odds ratio [OR]: 1.53 [95% confidence interval (CI): 1.20-1.95]; I2= 0%, p-value for heterogeneity= 0.44). This increased risk was primarily driven by non-melanoma cutaneous cancers (92 vs. 47; Peto OR: 1.77 [95% CI: 1.25-2.51]; I2 = 0%, p-value for heterogeneity = 0.54). However, there was no significant difference in the incidence of solid tumors (including malignant melanoma) (OR: 1.28 [95% CI: 0.85-1.95]) or hematologic SPMs (OR: 1.86; [95% CI: 0.81-4.27]). In conclusion, the use of anti-CD38 mAb-based combination regimens is associated with a higher risk of non-invasive cutaneous SPMs, but not solid tumors or hematologic SPMs. The increased occurrence of non-invasive cutaneous SPMs may be due to enhanced monitoring resulting from longer treatment duration with anti-CD38 mAbs.

A population level analysis of second hematological malignancies in chronic lymphocytic leukemia/small lymphocytic lymphoma survivors in the era of targeted therapies.

With improvement in survival after chronic lymphocytic leukemia (CLL) diagnosis, the real-world burden of second hematological malignancies (SHM) has not been comprehensively assessed in recent era. We analyzed risk, incidence, and outcomes of SHM in CLL patients between 2000 and 2019 using SEER database. CLL patients had greater risk for hematological malignancies than general population [SIR, standardized incidence ratio (95% CI):2.58 (2.46-2.70); p < 0.05]. The risk for subsequent lymphoma increased by 1.75 folds in 2015-2019 compared to 2000-2004. The duration, after CLL diagnosis, of maximum risk for SHM decreased as 60-119 months for time-period 2000-2004, 6-11 months for 2005-2009 to 2-5 months for 2010-2014 and 2015-2019. Incidence of SHM was 2.5% in CLL survivors (1736/70,346) with lymphoid SHM being more common than myeloid SHM, and DLBCL being the most common pathology (n = 610, 35% of all SHM). Male sex, age ≤65 years at CLL diagnosis, and chemotherapy treatment were associated with higher risk for SHM. The median gap between CLL and SHM diagnoses was 46 months. The median survival for de-novo-AML, t-MN, CML, and aggressive NHL was 63, 86, 95, and 96 months respectively. Although SHM remains rare, there is increased risk in recent era, likely due to improved survival in CLL patients, necessitating active surveillance strategies.

A validated composite comorbidity index predicts outcomes of CAR T-cell therapy in patients with diffuse large B-cell lymphoma.

Chimeric antigen receptor T-cell therapy (CART) has extended survival of patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). However, limited durability of response and prevalent toxicities remain problematic. Identifying patients who are at high risk of disease progression, toxicity, and death would inform treatment decisions. Although the cumulative illness rating scale (CIRS) has been shown to correlate with survival in B-cell malignancies, no prognostic score has been independently validated in CART recipients. We retrospectively identified 577 patients with relapsed/refractory DLBCL indicated for CART at 9 academic centers to form a learning cohort (LC). Random survival forest modeling of overall survival (OS) and progression-free survival (PFS) was performed to determine the most influential CIRS organ systems and severity grades. The presence of a severe comorbidity (CIRS score ≥ 3) in the respiratory, upper gastrointestinal, hepatic, or renal system, herein termed "Severe4," had the greatest impact on post-CART survival. Controlling for other prognostic factors (number of prior therapies, Eastern Cooperative Oncology Group performance status, BCL6 translocation, and molecular subtype), Severe4 was strongly associated with shorter PFS and OS in the LC and in an independent single-center validation cohort (VC). Severe4 was also a significant predictor of grade ≥3 cytokine release syndrome in the LC, while maintaining this trend in the VC. Thus, our results indicate that adverse outcomes for patients with DLBCL meant to receive CART can be predicted using a simplified CIRS-derived comorbidity index.

Host metabolome predicts the severity and onset of acute toxicities induced by CAR T-cell therapy.

Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy is a highly effective treatment option for patients with relapsed/refractory large B-cell lymphoma. However, widespread use is deterred by the development of clinically significant acute inflammatory toxicities, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), that induce significant morbidity and require close monitoring. Identification of host biochemical signatures that predict the severity and time-to-onset of CRS and ICANS may assist patient stratification to enable timely mitigation strategies. Here, we report pretreatment host metabolites that are associated with CRS and ICANS induced by axicabtagene ciloleucel or tisagenlecleucel therapy. Both untargeted metabolomics analysis and validation using targeted assays revealed a significant association between the abundance of specific pretreatment biochemical entities and an increased risk and/or onset of clinically significant CRS (q < .1) and ICANS (q < .25). Higher pretreatment levels of plasma glucose and lower levels of cholesterol and glutamate were associated with a faster onset of CRS. In contrast, low baseline levels of the amino acids proline and glycine and the secondary bile acid isoursodeoxycholate were significantly correlated with clinically significant CRS. Lower concentration of the amino acid hydroxyproline was associated with higher grade and faster onset of ICANS, whereas low glutamine was negatively correlated with faster development of ICANS. Overall, our data indicate that the pretreatment host metabolome has biomarker potential in determining the risk of clinically significant CRS and ICANS, and may be useful in risk stratification of patients before anti-CD19 CAR T-cell therapy.

Treatment outcomes with purine nucleoside analog alone or with rituximab for hairy cell leukemia at first relapse.

INTRODUCTION: Frontline treatment of hairy cell leukemia (HCL) with a single course of the purine nucleoside analog (PNA) produces a high rate of complete remission (CR) with prolonged durations. At the time of relapse, although treatment guidelines recommend re-treatment with a PNA alone or in combination with rituximab (R), practice patterns vary and data supporting each approach are limited. METHODS: We conducted a multisite outcomes analysis of patients treated for HCL between 1995 and 2018 at six US medical centers. All patients were treated with frontline PNA and subsequently required treatment with a PNA alone (PNA) or with R (+R). RESULTS: Of the 88 patients analyzed, 56 (63.6%) received second-line PNA and 22 (36.4%) received a PNA + R. Baseline characteristics of both groups were similar. There was no difference in median PFS [67 months (95% CI 43.8 non-reached (NR)) vs. 65 months (95% CI 60-NR)] or 5-year OS [98% (95% CI 0.94-1) vs. 94% (95% CI 0.83-1), p = .104] in the PNA versus PNA + R cohorts, respectively. CONCLUSION: To our knowledge, this is the largest study evaluating the role of R in treatment of relapsed HCL and suggests that there is no advantage to the addition of R to PNA therapy at the time of first re-treatment.

Critically Ill Patients Treated for Chimeric Antigen Receptor-Related Toxicity: A Multicenter Study.

OBJECTIVES: To report the epidemiology, treatments, and outcomes of adult patients admitted to the ICU after cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome. DESIGN: Retrospective cohort study. SETTING: Nine centers across the U.S. part of the chimeric antigen receptor-ICU initiative. PATIENTS: Adult patients treated with chimeric antigen receptor T-cell therapy who required ICU admission between November 2017 and May 2019. INTERVENTIONS: Demographics, toxicities, specific interventions, and outcomes were collected. RESULTS: One-hundred five patients treated with axicabtagene ciloleucel required ICU admission for cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome during the study period. At the time of ICU admission, the majority of patients had grade 3-4 toxicities (66.7%); 15.2% had grade 3-4 cytokine release syndrome and 64% grade 3-4 immune effector cell-associated neurotoxicity syndrome. During ICU stay, cytokine release syndrome was observed in 77.1% patients and immune effector cell-associated neurotoxicity syndrome in 84.8% of patients; 61.9% patients experienced both toxicities. Seventy-nine percent of patients developed greater than or equal to grade 3 toxicities during ICU stay, however, need for vasopressors (18.1%), mechanical ventilation (10.5%), and dialysis (2.9%) was uncommon. Immune Effector Cell-Associated Encephalopathy score less than 3 (69.7%), seizures (20.2%), status epilepticus (5.7%), motor deficits (12.4%), and cerebral edema (7.9%) were more prevalent. ICU mortality was 8.6%, with only three deaths related to cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome. Median overall survival time was 10.4 months (95% CI, 6.64-not available mo). Toxicity grade or organ support had no impact on overall survival; higher cumulative corticosteroid doses were associated to decreased overall and progression-free survival. CONCLUSIONS: This is the first study to describe a multicenter cohort of patients requiring ICU admission with cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome after chimeric antigen receptor T-cell therapy. Despite severe toxicities, organ support and in-hospital mortality were low in this patient population.

Influence of Killer Immunoglobulin-Like Receptors and Somatic Mutations on Transplant Outcomes in Acute Myeloid Leukemia.

Natural killer (NK) cells are regulated by killer immunoglobulin-like receptor (KIR) interactions with human leukocyte antigen class I ligands. Various models of NK cell alloreactivity have been associated with outcomes after allogeneic hematopoietic cell transplant (alloHCT), but results have varied widely. We hypothesized that somatic mutations in acute myeloid leukemia (AML) in the context of KIR profiles may further refine their association with transplant outcomes. In this single-center, retrospective, observational study, 81 AML patients who underwent matched-related donor alloHCT were included. Post-HCT outcomes were assessed based on mutational status and KIR profiles with the Kaplan-Meier method and log-rank test. On multivariable analysis those with any somatic mutations and C1/C2 heterozygosity had less acute graft-versus-host disease (GvHD) (hazard ratio [HR], 0.32; 95% confidence interval [CI], 0.14-0.75; P = .009), more relapse (HR, 3.02; 95% CI, 1.30-7.01; P = .010), inferior relapse-free survival (RFS; HR, 2.22; 95% CI, 1.17-4.20; P = .014), and overall survival (OS; HR, 2.21; 95% CI, 1.17-4.20; P = .015), whereas those with a missing KIR ligand had superior RFS (HR, 0.53; 95% CI, 0.30-0.94; P = .031). The presence of a somatic mutation and donor haplotype A was also associated with less acute GvHD (HR, 0.38; 95% CI, 0.16-0.92; P = .032), more relapse (HR, 2.72; 95% CI, 1.13-6.52; P = .025), inferior RFS (HR, 2.11; 95% CI, 1.07-4.14; P = .030), and OS (HR, 2.20; 95% CI, 1.11-4.38; P = .024). Enhanced NK cell alloreactivity from more KIR activating signals (donor B haplotype) and fewer inhibitory signals (recipient missing KIR ligand or C1 or C2 homozygosity) may help mitigate the adverse prognosis associated with some AML somatic mutations. These results may have implications for improving patient risk stratification prior to transplant and optimizing donor selection.

HIV-associated Burkitt lymphoma: outcomes from a US-UK collaborative analysis.

Data addressing prognostication in patients with HIV related Burkitt lymphoma (HIV-BL) currently treated remain scarce. We present an international analysis of 249 (United States: 140; United Kingdom: 109) patients with HIV-BL treated from 2008 to 2019 aiming to identify prognostic factors and outcomes. With a median follow up of 4.5 years, the 3-year progression-free survival (PFS) and overall survival (OS) were 61% (95% confidence interval [CI] 55% to 67%) and 66% (95%CI 59% to 71%), respectively, with similar results in both countries. Patients with baseline central nervous system (CNS) involvement had shorter 3-year PFS (36%) compared to patients without CNS involvement (69%; P < .001) independent of frontline treatment. The incidence of CNS recurrence at 3 years across all treatments was 11% with a higher incidence observed after dose-adjusted infusional etoposide, doxorubicin, vincristine, prednisone, cyclophosphamide (DA-EPOCH) (subdistribution hazard ratio: 2.52; P = .03 vs other regimens) without difference by CD4 count 100/mm3. In multivariate models, factors independently associated with inferior PFS were Eastern Cooperative Oncology Group (ECOG) performance status 2-4 (hazard ratio [HR] 1.87; P = .007), baseline CNS involvement (HR 1.70; P = .023), lactate dehydrogenase >5 upper limit of normal (HR 2.09; P < .001); and >1 extranodal sites (HR 1.58; P = .043). The same variables were significant in multivariate models for OS. Adjusting for these prognostic factors, treatment with cyclophosphamide, vincristine, doxorubicin, and high-dose methotrexate, ifosfamide, etoposide, and high-dose cytarabine (CODOX-M/IVAC) was associated with longer PFS (adjusted HR [aHR] 0.45; P = .005) and OS (aHR 0.44; P = .007). Remarkably, HIV features no longer influence prognosis in contemporaneously treated HIV-BL.

Brexucabtagene autoleucel for the treatment of relapsed/refractory mantle cell lymphoma.

Introduction: The therapeutic options for mantle cell lymphoma (MCL) include traditional chemo-immunotherapy for newly diagnosed cases, and targeted treatments including the bruton tyrosine kinase inhibitors in the relapsed/refractory (R/R) disease setting. The advent of commercially available chimeric antigen receptor (CAR) T-cell therapy in the last three years has dramatically improved the outcomes of patients with R/R large B-cell lymphoma.Areas covered: This review is an in-depth evaluation and appraisal of brexucabtagene autoleucel (brexu-cel), the first anti-CD19 CAR T-cell therapy to be approved for patients with R/R MCL, after the results of a Phase II (ZUMA-2) trial.Expert opinion: In the absence of head-to-head comparison studies with Btk inhibitors, up-front use of brexu-cel in patients with high-risk MCL and poor prognostic features may be advantageous, possibly even before exposure to Btk inhibitor, and further study of this approach is warranted. While data on long-term outcomes of CAR T-cell therapy in MCL patients are needed, brexu-cel has shown remarkable clinical activity and its regulatory approval has immediate practice-changing implications in this highly aggressive malignancy.

Late occurrence of progressive multifocal leukoencephalopathy after anti-CD19 chimeric antigen receptor T-cell therapy.

Progressive multifocal leukoencephalopathy (PML) is a life-threatening infection of the central nervous system in immunocompromised patients, with an established predilection in non-Hodgkin's lymphoma and stem cell transplant recipients. In the era of chimeric antigen receptor T-cell therapy (CAR T-cell), the occurrence of new-onset neurological symptoms and encephalopathy in this patient population can be attributed to a variety of factors, including therapy-related neurotoxicity or disease progression. PML has not been implicated as a common cause of encephalopathy in CAR T-cell therapy recipients, and the identification of such rare infections is important to guide prognosis and treatment decisions. We hereby report the first case of late occurrence of PML, over one year after CAR T-cell therapy, for a patient with relapsed large B-cell lymphoma.

Outcomes and factors impacting use of axicabtagene ciloleucel in patients with relapsed or refractory large B-cell lymphoma: results from an intention-to-treat analysis.

Data on real-world outcomes of axicabtagene ciloleucel (axi-cel) therapy for relapsed/refractory large B-cell lymphoma (R/R LBCL) are limited. In this intent to treat (ITT) analysis, we reviewed records of 38 consecutive patients with R/R LBCL for whom axi-cel was intended. Twenty-seven (71%) patients received axi-cel and 11 (29%) did not. Patients in the non-axi-cel group had a higher hematopoietic cell transplantation comorbidity index (HCT-CI) (median 4 vs. 2, p = .04). Median overall survival for the ITT, axi-cel and non-axi-cel group was 10 (95% CI, 3.7 to 13), 13 (95% CI, 7.7 to N.R.) and 1 (95% CI, 0.4 to 3.7) month(s) respectively. Factors limiting axi-cel use were disease progression, sepsis, manufacturing failure and socioeconomic barrier in 6 (55%), 3 (27%), 1 (9%) and 1 (9%) patient(s) respectively. Additional strategies are needed to ensure all LBCL patients for whom chimeric antigen receptor (CAR) T-cell therapy is prescribed can receive this treatment.

Comorbidities Predict Inferior Survival in Patients Receiving Chimeric Antigen Receptor T Cell Therapy for Diffuse Large B Cell Lymphoma: A Multicenter Analysis.

Chimeric antigen receptor T cell (CAR-T) therapy is approved for treatment of relapsed/refractory (R/R) diffuse large B cell lymphoma (DLBCL). Here we evaluate whether comorbidities, calculated using the Cumulative Illness Rating Scale (CIRS), predict survival for these patients. A retrospective chart review was performed at 4 academic institutions. All patients who underwent leukapheresis for commercial CAR-T therapy for R/R DLBCL were included. CIRS scores were calculated at the time of leukapheresis. High comorbidity was defined as either CIRS ≥7 or the presence of severe impairment (CIRS 3/4 in ≥1 system; CIRS-3+). Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method, and differences in curves were detected by the log-rank test. A total of 130 patients were analyzed, 56.9% with CIRS ≥7 and 56.2% with CIRS-3+. After a median follow-up of 13 months, the median PFS was 6.7 months, and the median OS was not reached. On univariable analysis, Eastern Cooperative Oncology Group (ECOG) performance status (PS) was associated with inferior PFS (hazard ratio [HR], 1.45; 95% confidence interval [CI], 1.03-2.05; P = .03) and OS (HR, 1.76; 95% CI, 1.17-2.64; P = .007). Higher CIRS (CIRS ≥7 or CIRS-3+) was associated with inferior OS (HR, 2.12; 95%, CI, 1.06-4.22; P = .03) and a nonsignificant trend in worse PFS (HR, 1.45; 95% CI, .87-2.44; P = .16). In multivariable analyses, CIRS ≥7 or CIRS-3+ and ECOG PS maintained independent prognostic significance. Comorbidities as determined by CIRS and ECOG PS predict inferior survival in patients receiving CAR-T therapy for R/R DLBCL.

The association of D-dimers with mortality, intensive care unit admission or acute respiratory distress syndrome in patients hospitalized with coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis.

AIM: To determine if D-dimers are elevated in individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection who have adverse clinical outcomes including all-cause mortality, intensive care unit (ICU) admission or acute respiratory distress syndrome (ARDS). METHODS: We conducted a systematic review and meta-analysis of the published literature in PubMed, Embase and Cochrane databases through April 9, 2020 for studies evaluating D-dimer levels in SARS-COV-2 infected patients with and without a composite clinical endpoint, defined as the presence of all-cause of mortality, Intensive care unit (ICU) admission or acute respiratory distress syndrome (ARDS). A total of six studies were included in the meta-analysis. RESULTS: D-dimers were significantly increased in patients with the composite clinical end point than in those without (SMD, 1.67 ug/ml (95% CI, 0.72-2.62 ug/ml). The SMD of the studies (Tang et al, Zhou et al, Chen et al), which used only mortality as an outcome measure was 2.5 ug/mL (95% CI, 0.62-4.41 ug/ml). CONCLUSION: We conclude that SARS-CoV-2 infected patients with elevated D-dimers have worse clinical outcomes (all-cause mortality, ICU admission or ARDS) and thus measurement of D-dimers can guide in clinical decision making.

Burkitt lymphoma in the modern era: real-world outcomes and prognostication across 30 US cancer centers.

We examined adults with untreated Burkitt lymphoma (BL) from 2009 to 2018 across 30 US cancer centers. Factors associated with progression-free survival (PFS) and overall survival (OS) were evaluated in univariate and multivariate Cox models. Among 641 BL patients, baseline features included the following: median age, 47 years; HIV+, 22%; Eastern Cooperative Oncology Group (ECOG) performance status (PS) 2 to 4, 23%; >1 extranodal site, 43%; advanced stage, 78%; and central nervous system (CNS) involvement, 19%. Treatment-related mortality was 10%, with most common causes being sepsis, gastrointestinal bleed/perforation, and respiratory failure. With 45-month median follow-up, 3-year PFS and OS rates were 64% and 70%, respectively, without differences by HIV status. Survival was better for patients who received rituximab vs not (3-year PFS, 67% vs 38%; OS, 72% vs 44%; P < .001) and without difference based on setting of administration (ie, inpatient vs outpatient). Outcomes were also improved at an academic vs community cancer center (3-year PFS, 67% vs 46%, P = .006; OS, 72% vs 53%, P = .01). In multivariate models, age ≥ 40 years (PFS, hazard ratio [HR] = 1.70, P = .001; OS, HR = 2.09, P < .001), ECOG PS 2 to 4 (PFS, HR = 1.60, P < .001; OS, HR = 1.74, P = .003), lactate dehydrogenase > 3× normal (PFS, HR = 1.83, P < .001; OS, HR = 1.63, P = .009), and CNS involvement (PFS, HR = 1.52, P = .017; OS, HR = 1.67, P = .014) predicted inferior survival. Furthermore, survival varied based on number of factors present (0, 1, 2 to 4 factors) yielding 3-year PFS rates of 91%, 73%, and 50%, respectively; and 3-year OS rates of 95%, 77%, and 56%, respectively. Collectively, outcomes for adult BL in this real-world analysis appeared more modest compared with results of clinical trials and smaller series. In addition, clinical prognostic factors at diagnosis identified patients with divergent survival rates.

Real-world Experience of Imatinib in Pediatric Chronic Phase Chronic Myeloid Leukemia: A Single-center Experience From India.

INTRODUCTION: Chronic myeloid leukemia (CML) is an uncommon malignancy in children in which tyrosine kinase inhibitors (TKIs) have significantly improved outcome in recent years. PATIENTS AND METHODS: We performed a retrospective analysis of CML patients (≤ 18 years old) presenting to our center between January 2005 and December 2018 with respect to baseline demographics, response to imatinib, and real-world management of those with a suboptimal response. RESULTS: A total of 124 patients were diagnosed with CML with 99 (80%) in the chronic phase. There was a male preponderance (males:females = 3.1:1) with a median age of 13 years. The common presenting clinical features were splenomegaly (90.9%) and fever (51.5%) with a median leukocyte count of 165 × 103/µL. The proportion of patients attaining a complete hematologic response (CHR) at 3 months, a complete cytogenetic response (CCyR) at 12 months, and a major molecular response at 12 months were 79.7%, 54.1%, and 50.9%, respectively. At a median follow-up of 67.4 months, the 5-year overall survival rate and the event-free survival (EFS) rate were 92% ± 3% and 64% ± 6%, respectively. Failure to achieve CCyR at 12 months was associated with poor EFS beyond 1 year (hazard ratio = 2.865, P = .044). Among 15 patients not achieving CHR at 3 months, dose escalation of imatinib resulted in the attainment of CHR in 13 (87%) patients. Seven patients in the cohort had a loss of the established response to imatinib because of documented poor compliance. CONCLUSION: Imatinib remains the frontline treatment of choice in CML with a reasonable outcome in children, especially when financial affordability, availability of second-generation TKIs, and poor compliance still remain major challenges in management. Dose escalation of imatinib remains an option in patients with a suboptimal response.

Percutaneous mitral commissurotomy versus surgical commissurotomy for rheumatic mitral stenosis: a systematic review and meta-analysis of randomised controlled trials.

AIM: Patients with severe mitral stenosis (MS) and their clinicians typically choose percutaneous transvenous mitral commissurotomy (PTMC) over surgical commissurotomy (SC). However, the durability of PTMC relative to SC is uncertain. We compared the efficacy, safety and durability of PTMC with SC for the treatment of MS. METHODS: We searched EMBASE, MEDLINE and WHO ICTRP registers for randomised controlled trials (RCTs) comparing PTMC, and open and/or closed mitral commissurotomy. The principal outcomes were rate of re-intervention and symptomatic improvement as inferred from the surrogate measures of immediate postprocedural mitral valve area (MVA), MVA at ≥6 month follow-up, incidence of mitral regurgitation (MR) and restenosis. We calculated weighted mean differences (WMD) for continuous outcomes, relative risks (RR) for binary outcomes and pooled outcomes using random-effects models and assessed the quality of evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS: Seven RCTs with 553 patients proved eligible. Pooled estimates showed no convincing difference in the risk of restenosis or re-intervention (15/100 fewer with PTMC, 95% CI (-20 to +8); quality of evidence: moderate) or in symptoms as inferred from immediate MVA (WMD 0.15, 95% CI (-0.18 to 0.48): very low), from the incidence of postprocedural severe MR (3/100 more with PTMC, 95% CI (-1 to +10): moderate) or from MVA at 30 months. CONCLUSION: Until data demonstrating convincing superiority of SC over PTMC become available, our results support the current practice of recommending PTMC to young patients with MS and favourable valve morphology, as it is associated with lower peri-procedural morbidity. PROSPERO REGISTRATION NUMBER: PROSPERO 2017 (CRD42017079512).