One of the world’s biggest trials of COVID-19 therapies released its long-awaited interim results yesterday—and they’re a letdown. None of the four treatments in the Solidarity trial, which enrolled more than 11,000 patients in 400 hospitals around the globe, increased survival—not even the much-touted antiviral drug remdesivir. Scientists at the World Health Organization (WHO) released the data as a preprint on medRxiv last night, ahead of its planned publication in The New England Journal of Medicine.
Yet scientists praised the unprecedented study itself and the fact that it helped bring clarity about four existing, ”repurposed” treatments that each held some promise against COVID-19. “It's disappointing that none of the four have come out and shown a difference in mortality, but it does show why you need big trials,” says Jeremy Farrar, director of the Wellcome Trust. “We would love to have a drug that works, but it’s better to know if a drug works or not than not to know and continue to use it,” says WHO’s chief scientist, Soumya Swaminathan.
In the absence of approved, effective treatments for COVID-19, some hospitals have been treating patients with severe COVID symptoms with blood plasma from recovering patients. The blood of recovered patients contains antibodies that act against the coronavirus. While plasma hasn’t yet shown a benefit in randomized trials, some small retrospective studies suggest it may reduce illness severity and reduce hospitalization time.
This week in mBio, an open-access journal of the American Society for Microbiology, researchers report that antibody levels in the blood of COVID-19 patients drop rapidly during the weeks after their bodies have cleared the virus and symptoms have subsided. If convalescent plasma is ultimately shown to have a clear benefit, the authors concluded, then it needs to be collected during a specific window of time after recovery. However, recovering patients can’t donate blood until at least 14 days after symptoms have subsided, to give the body time to clear viral particles.
“We don’t want to transfuse the virus, just transfuse the antibodies,” said Andrés Finzi, Ph.D., at the University of Montreal, in Canada. “But at the same time, our work shows that the capacity of the plasma to neutralize viral particles is going down during those first weeks.”