Researchers at UCSF are leading a clinical trial to test whether blood plasma therapy, a treatment touted by the Trump Administration in August as a “major therapeutic breakthrough,” is effective for treating hospitalized COVID-19 patients.
The therapy involves treating infected patients with plasma collected from people who have recovered from COVID-19. Most people who recover from the disease develop proteins produced by the immune system known as antibodies, which can fight off SARS-CoV-2, the virus that causes COVID-19. The antibodies are found in a portion of the blood called plasma, and scientists are hoping that infusing the convalescent plasma into COVID-19 patients can help fend off an infection.
The Food and Drug Administration issued an emergency authorization in August to expand convalescent plasma treatment of hospitalized COVID-19 patients — a day after President Donald Trump accused the agency of delaying enrollment in COVID-19 clinical trials. The timing led some to believe the announcement was politically motivated.
A panel of the National Institutes of Health later said there is insufficient evidence to show that the treatment is effective against the disease.
Now, Professor Annie Leutkemeyer of UCSF is co-leading a study in collaboration with Zuckerberg San Francisco General Hospital and Vitalant Research Institute involving 50 participants, using the gold standard for assessing therapies — a randomized controlled trial involving a control group and another receiving the actual treatment. The study will test whether convalescent plasma can reduce the chances of death or reliance on mechanical ventilators for hospitalized COVID-19 patients, and the researchers will pool the data with other studies to ensure that the results are robust.
“[Convalescent plasma] is one of the oldest strategies that we have had in infectious diseases,” Leutkemeyer said at a news conference on Wednesday. “It predates the antibiotic era. And it was used in other viral diseases with varying levels of success.”
Past research between 1918 and 1925 suggests that patients infected with the Spanish flu who received convalescent plasma were less likely to die. While research shows that the convalescent plasma treatments for the severe acute respiratory syndrome and the middle east respiratory syndrome caused by other coronaviruses may be effective, the data is not robust enough for definitive conclusions.
In the case of COVID-19, Leutkemeyer said recent observational studies, which do not involve assigning participants in controlled experiments, showed encouraging results.
“Observational studies are very useful and they’re informative. They can tell us about safety and about trends towards efficacy,” she said. “But randomized trials will always be preferred to establish true benefits. We have a number of cases throughout the history of modern medicine where observational studies really suggested that various treatments would be effective.” But the results did not always translate to randomized controlled trials.
Leutkemeyer said three randomized controlled trials of convalescent plasma for treating COVID-19 patients were stopped early and none of them yielded conclusive evidence, although there were some positive results.
There remain unanswered questions regarding convalescent plasma as a therapy for COVID-19 patients, Leutkemeyer said. For one, what type of patients may yield the most benefit from the treatment? And would the administration of remdesivir and steroids, drugs proven effective for some patients, diminish the potential benefits of convalescent plasma?
“While I know it’s frustrating for all of us to still have unanswered questions, every once in a while, I have a moment when I have to say: ‘It’s been six months and it’s pretty amazing with what we have come up with — the massive mobilization of the research community both in the U.S. and internationally, and the barriers that have been knocked down to get work [done] that would have taken me months or years to get done,’” Leutkemeyer said.
Scientists have made home runs in finding effective treatments for COVID-19 like remdesivir and steroids, she said.
“I am very heartened by the speed and the progress that we’ve had so far … but we all know the maximum amount of suffering that’s going on and the impact that the virus has had,” Leutkemeyer said. “Now is not a time to let up on those efforts.”