This article originally appeared on the Bloomberg School of Public Health website.
Researchers from the Johns Hopkins Bloomberg School of Public Health supported the first blood center in the U.S. to be granted full FDA approval to provide convalescent plasma to immunocompromised COVID-19 patients who are unable to make their own antibodies to fight the virus that causes COVID-19.
OneBlood, a nonprofit blood center serving much of the southeastern United States, announced last month that it had worked with several partners, including Johns Hopkins and the Mayo Clinic, to provide data to the FDA to prove that convalescent plasma is a safe and effective treatment for immunocompromised COVID-19 patients.
Arturo Casadevall, a Bloomberg Distinguished Professor and chair of the Department of Molecular Microbiology and Immunology (MMI) at the Bloomberg School, and David Sullivan, an infectious diseases physician and professor in MMI, have been focused on COVID-19 convalescent plasma (CCP) since early 2020—just as the pandemic began. In February 2020, Casadevall published a Wall Street Journal op-ed highlighting the benefits of using antibodies in the blood of recovered patients to treat others at risk of infection. He co-led the national and international COVID-19 Convalescent Plasma Project, which mobilized convalescent plasma to save lives in those hospitalized.
Image caption: Arturo Casadevall and David Sullivan
Image credit: Bloomberg School of Public Health
Casadevall and Sullivan were leaders on the outpatient study "Early Outpatient Treatment for Covid-19 with Convalescent Plasma," with colleagues from the Johns Hopkins School of Medicine, published in the New England Journal of Medicine in 2022. The paper detailed findings of a national multi-site randomized control trial that showed that CCP safely reduced hospitalizations in early outpatient treatment. A week after the results were publicly shared in a pre-print publication in 2021, the FDA authorized CCP therapy for emergency use in immunocompromised outpatients. Previously, CCP had been only authorized for use in hospitalized patients.
The outpatient study was recognized as a 2023 Top Ten Clinical Research Achievement Award by the Clinical Research Forum.
For Sullivan and Casadevall, this full FDA approval—the first ever for convalescent plasma, and based in part on their CCP research and expertise—is a blueprint to use convalescent plasma in future pandemics. Here, Sullivan and Casadevall discuss their recommendation to explore the use of convalescent plasma at scale in public health preparedness planning for future disease outbreaks and pandemics.
Why is the FDA's approval significant?
David Sullivan: The FDA formally approved the Biologic License Application for polyclonal CCP for the immunosuppressed. Full FDA approval for CCP is hugely impactful for immunocompromised patients who are unable to generate on their own sufficient antibodies to fight COVID-19. The approval will make high quality convalescent plasma more available. This approval also paves the way for convalescent plasma to be used as a treatment for future infectious disease outbreaks, epidemics, and pandemics, after we've established effectiveness for other pathogens.
What is high titer convalescent plasma?
Sullivan: People who have recovered from the coronavirus and/or who have been vaccinated for COVID-19 have developed antibodies to the virus that remain in the plasma portion of their blood. COVID-19 convalescent plasma with a high level of antibodies may be used to help people diagnosed with COVID-19 who have a weakened immune system. The current high titer antibody levels are more than 20 times the levels FDA allowed under the 2021 emergency allowance.
COVID-19 convalescent plasma therapy is used to prevent or treat severe or life-threatening complications from COVID-19. It helps by providing antibodies the immune system can't make or can't make fast enough.
How many people does "immunocompromised patients" refer to?
Arturo Casadevall: Three percent of the U.S. population is 10 million immunocompromised people. We're talking about a significant number of people who could be positively impacted by this recent FDA approved treatment.
To compare, what percentage of COVID-19 cases impacted patients who are immunocompromised?
Casadevall: Twenty percent of all COVID-19 hospitalized cases involved immunocompromised patients.
How is convalescent plasma different from monoclonal antibodies which have failed due to evolving variants?
Sullivan: Recently collected plasma (within six months of transfusion), qualified with high antibody levels, has hundreds of diverse antibodies which have been proven to neutralize future variants of concern. In this way convalescent plasma is better able to keep up with the variants than vaccines or monoclonal antibodies.
What did you learn from your work with convalescent plasma during the pandemic?
Casadevall: For the next pandemic or infectious-disease emergency, we recommend preparing having outpatient facilities ready to treat high-risk, immunocompromised patients. We would immediately try to identify who is most at risk, and then plan to secure convalescent plasma for these specific populations.
How will this FDA approval help advance CCP in use in future pandemics?
Sullivan: OneBlood is now able to provide high titer CCP from people who have recovered from COVID-19 for use by individuals who are immunocompromised and unable to make their own antibodies. CCP will need to be tested to determine if it is effective against other, different pathogens. If it can, treatment can be replicated by doctors and hospitals throughout the country for future pandemics. This approval is a big deal. It's exciting, and it gives us hope as we plan and prepare for future pandemics. I'd like to think we played a small part in moving the needle in terms of emergency preparedness for future outbreaks and pandemics.
Johns Hopkins research into convalescent plasma as a COVID-19 treatment was supported by a Bloomberg Philanthropies and State of Maryland private-public initiative, Department of Defense funding, National Institutes of Health NIAID and NCATS grants, and funding from the Mental Wellness Foundation, Moriah Fund, Octapharma, HealthNetwork and Shear Family Foundation.
