Mark McClellan, Margaret Hamburg, Robert Califf and Scott Gottlieb are former commissioners of the Food and Drug Administration.

President Trump last week called on those who have recovered from covid-19 to donate their blood plasma as a potential treatment for help stem the pandemic. More work has yet to be done to demonstrate that such a therapy is safe and effective, but if so, it could help millions of patients with the novel coronavirus both here and abroad.

The United States could desperately use such a treatment. The nation continues to struggle with high rates of hospitalizations and tragic deaths. While vaccine development continues, it’s important to advance every promising treatment option to improve the odds for those who become sick.

Blood plasma — also known as convalescent plasma — has been used as a therapy for infectious diseases for a century, including against the flu in 1918 as well as SARS, Ebola, meningitis and measles. While it doesn’t work for all infections, the idea is to use one person’s successful defense system of antibodies to bolster the immune response of a newly infected person.

The United States has been the leading global supplier of plasma products. Now, we’re also the world’s leading supplier of coronavirus cases, with around 60,000 a day. If convalescent plasma does help, it could help mitigate the impact of the pandemic.

But if this is going to work, we need to do it right. We need a concerted effort to collect blood plasma, along with clinical trials to determine when its benefits outweigh the risks so we can treat the right people at the right time. With that evidence in hand, we need to maintain a highly synchronized distribution system to get the plasma to the right health-care facilities in a timely and equitable way.

The good news is the work is already underway. A broad coalition of medical and research institutions, blood centers, life science and technology companies, philanthropic organizations and covid-19 survivor groups has already come together to launch a campaign. This group, called The Fight Is In Us, is working to drive awareness and recruit plasma donors across the country.

This effort should be coupled with serious studies to figure out whether and when plasma works. Thousands of covid-19 patients have been treated with plasma, but we are not much closer to definitively answering those questions. Its use makes common sense, and preliminary studies are promising, but we won’t know how to best use convalescent plasma products until we complete randomized clinical trials in which some people are treated and others receive usual care.

Consider the confusion surrounding the use of hydroxychloroquine as a treatment for covid-19. Early studies without randomization gave contradictory results. We couldn’t tell if hydroxychloroquine had an effect or if differences in the mortality rates were due to something else.

Subsequent randomized trials showed no meaningful benefit and, in some trials, significant side effects and worse outcomes, enabling us to conclude hydroxychloroquine isn’t providing an advantage and allowing us to focus attention on more promising treatments.

Randomization might sound arbitrary, but we have only a limited supply of plasma, and we don’t yet know if it’s the plasma or something else that might make a patient better or worse. Maintaining clear and consistent standards for proving the safety and effectiveness of treatments will be critical in building trust in both treatments and an eventual vaccine.

The federal government’s ACTIV program, part of Operation Warp Speed, is standing up trials of promising treatments, including convalescent plasma and synthetic antibodies that work through mechanisms similar to plasma to neutralize the virus. But only a small fraction of covid-19 patients are currently able to participate in the plasma trials.

The Recovery trial in Britain has shown how to do these evaluations at the scale and speed required. By keeping enrollment and participation simple for patients and busy clinicians, while giving patients access to all the care that we know works, Recovery has made it easy for thousands of sick patients who wish to do so to participate in studies to learn what else works for them, and for future patients. Recovery showed that steroids worked in some patients, and that hydroxychloroquine generally didn’t. It’s studying convalescent plasma now, but there are far more patients who could participate in similar trials in the United States.

Given the urgency of the covid-19 crisis, we need to create new pathways for quickly advancing promising therapies while clearly determining whether they’re safe and effective. We can’t waste precious time and put people at risk by treating them with therapies that don’t work or miss opportunities to collect data and determine when a treatment is beneficial. A coordinated campaign such as The Fight Is In Us plus expanded clinical trials give us an opportunity to secure these opportunities for patients.

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