Erin Jamula

The efficacy of convalescent plasma for coronavirus disease 2019 (COVID-19) is unclear. Although most randomized controlled trials have shown negative results, uncontrolled studies have suggested that the antibody content could influence patient outcomes. We conducted an open-label, randomized controlled trial of convalescent plasma for adults with COVID-19 receiving oxygen within 12 d of respiratory symptom onset ( NCT04348656 ). Patients were allocated 2:1 to 500 ml of convalescent plasma or standard of care. The composite primary outcome was intubation or death by 30 d. Exploratory analyses of the effect of convalescent plasma antibodies on the primary outcome was assessed by logistic regression. The trial was terminated at 78% of planned enrollment after meeting stopping criteria for futility. In total, 940 patients were randomized, and 921 patients were included in the intention-to-treat analysis. Intubation or death occurred in 199/614 (32.4%) patients in the convalescent plasma arm and 86/307 (28.0%) patients in the standard of care arm-relative risk (RR) = 1.16 (95% confidence interval (CI) 0.94-1.43, P = 0.18). Patients in the convalescent plasma arm had more serious adverse events (33.4% versus 26.4%; RR = 1.27, 95% CI 1.02-1.57, P = 0.034). The antibody content significantly modulated the therapeutic effect of convalescent plasma. In multivariate analysis, each standardized log increase in neutralization or antibody-dependent cellular cytotoxicity independently reduced the potential harmful effect of plasma (odds ratio (OR) = 0.74, 95% CI 0.57-0.95 and OR = 0.66, 95% CI 0.50-0.87, respectively), whereas IgG against the full transmembrane spike protein increased it (OR = 1.53, 95% CI 1.14-2.05). Convalescent plasma did not reduce the risk of intubation or death at 30 d in hospitalized patients with COVID-19. Transfusion of convalescent plasma with unfavorable antibody profiles could be associated with worse clinical outcomes compared to standard care.

BACKGROUND: The anti-CD20 monoclonal antibody rituximab has immune-modulatory effects similar to intravenous immunoglobulin (IVIG). We performed a systematic review and meta-analysis to determine the efficacy and safety of rituximab in autoimmune diseases that are also treated with IVIG. STUDY DESIGN AND METHODS: The most common indications for immune modulation with IVIG, as identified from a 2012 regional audit in Canada, were chronic inflammatory demyelinating polyneuropathy (CIDP), immune thrombocytopenia (ITP), myasthenia gravis, multifocal motor neuropathy, Guillain-Barré syndrome, systemic lupus erythematosus (SLE), Sjogren's syndrome, and pemphigus vulgaris. We searched MEDLINE, EMBASE, and the Cochrane Library until July 2016 for studies evaluating rituximab in each of these conditions. The primary outcome in our meta-analysis was clinical response at 6 months as defined by disease-specific criteria in randomized trials. We also calculated pooled proportions of responders within disease types from observational studies. RESULTS: Ninety-five rituximab studies were identified: 86 were observational studies in patients with ITP (n = 1746), SLE (n = 1047), pemphigus vulgaris (n = 564), Sjogren's syndrome (n = 138), myasthenia gravis (n = 66), and CIDP (n = 31) and nine were randomized controlled trials (n = 992) in patients with ITP, SLE, and Sjogren's syndrome that compared rituximab with placebo plus standard of care. Among randomized trials, response rates were higher with rituximab (relative risk, 1.38; 95% confidence interval [CI], 1.05-1.83). The pooled proportion of rituximab responses ranged from 94% (95% CI, 88%-98%) for pemphigus vulgaris to 48% (95% CI, 30%-66%) for CIDP. Rituximab was generally well tolerated in observational studies although in the randomized trials, adverse events were more common in the rituximab group. CONCLUSION: Rituximab is an immune-modulating agent with biologic activity across many autoimmune conditions. Our data support the use of comparative trials with broad eligibility criteria to evaluate rituximab as an alternative to IVIG in autoimmune diseases.