Another COVID-19 convalescent plasma trial ends prematurely

The NIH announced that it is ending a clinical trial evaluating the safety and effectiveness of COVID-19 convalescent plasma in ED patients with mild to moderate symptoms.

After an interim analysis of the Clinical Trial of COVID-19 Convalescent Plasma of Outpatients (C3PO), an independent data and safety monitoring board “determined that while the convalescent plasma intervention caused no harm, it was unlikely to benefit this group of patients,” an NIH press release said.

This is the second COVID-19 convalescent plasma trial to end prematurely. In January, recruitment for the convalescent plasma arm of the RECOVERY trial was closed after an independent board determined there was no evidence the treatment benefited patients with COVID-19.

According to the NIH, C3PO was being conducted at 47 hospitals across the United States. The recruitment goal was 900 participants; 511 had been recruited before the decision was made to stop the clinical trial.

The study investigators were examining how adults who presented to the ED within 1 week of mild to moderate COVID-19 symptoms responded to a convalescent plasma injection from an adult who had recovered from COVID-19. None of the C3PO participants, who also had at least one risk factor associated with severe COVID-19, “were ill enough” to be hospitalized at time of ED presentation, the NIH said.

After receiving either COVID-19 convalescent plasma or placebo, investigators tracked C3PO participants to determine whether they needed additional emergency or urgent care, were hospitalized or died within 15 days of entering the trial. The recent analysis of C3PO did not demonstrate a significant difference in the proportion of patients who experienced these outcomes, according to the NIH. Even if the trial continued, it was “highly unlikely” to show that convalescent plasma prevents progression from mild to severe illness in this population, the release said.

Separately, a meta-analysis of randomized controlled trials that was recently published in JAMA also found no statistically significant benefit of convalescent plasma compared with control in patients with COVID-19. However, data published in The New England Journal of Medicine in January suggested high-titer convalescent plasma might benefit patients with COVID-19 who are not on mechanical ventilation.

In August, the FDA had authorized the use of convalescent plasma for hospitalized patients with COVID-19 amid questions about its usefulness. At the time, then FDA Commissioner Stephen M. Hahn, MD, said the agency was “encouraged” by initial data showing that patients with COVID-19 who received convalescent plasma early enough in their illness were less likely to die.

References:

Janiaud P, et al. JAMA. 2021;doi:10.1001/jama.2021.2747.

NIH. NIH halts trial of COVID-19 convalescent plasma in emergency department patients with mild symptoms. https://www.nih.gov/news-events/news-releases/nih-halts-trial-covid-19-convalescent-plasma-emergency-department-patients-mild-symptoms. Accessed March 3, 2021.