People who fight off COVID-19 carry a powerful memento in their blood: antibodies that are primed to wipe out the disease. By lending these trained immune soldiers to other patients, survivors might be able to knock out three cases of COVID for the price of one.
Antibody-rich blood plasma from people who have overcome COVID-19 is now helping to jumpstart immune defenses in patients struggling with the disease at UAB Hospital. Recently, UAB physicians treated three patients as part of an expanded-access clinical trial in collaboration with the Mayo Clinic, says Sonya Heath, M.D., professor of medicine in the Division of Infectious Diseases at the University of Alabama at Birmingham.
“The idea behind convalescent plasma is to take a donation from someone who had COVID-19 and recovered, and the immune response they developed may be able to help the patients who are treated with that plasma,” Heath said; she is the principal investigator at UAB for the study, which received expedited approval from the Food and Drug Administration in early April. Heath is working with Todd McCarty, M.D., assistant professor in the Division of Infectious Diseases, on the effort.
Could see benefit within 72 hours
Patients who are potential candidates for the trial include anyone hospitalized with COVID-19 “who is not getting better,” Heath said. Symptoms include shortness of breath, fast respiratory rate and “showing signs they are declining in terms of their ability to oxygenate,” Heath said. “We believe that, the earlier we treat people, the more effective this will be.” She expects to see a benefit within about 72 hours of treatment’s beginning, Heath added.
Convalescent plasma therapy has proved effective during previous outbreaks of severe respiratory infections, including SARS in 2003, H1N1 in 2009 and MERS in 2012. There are indications that the experimental treatment works for COVID-19 as well. In early April, the journal Proceedings of the National Academies of Sciences published a small study from China, in which 10 adults with severe COVID-19 received the therapy. Within three days of their transfusions, the patients’ symptoms had improved rapidly. After a week, virus levels in the patients’ blood were undetectable and lung damage had improved. No severe adverse effects were reported.
The Mayo Clinic trial being conducted at UAB is not a placebo-controlled trial, Heath says.
“Everyone who enrolls gets plasma, and we are using this to treat patients with COVID-19 who are hospitalized on the floor or in ICU,” Heath said. “By contributing the clinical outcomes of all these patients along with other hospitals, we will be able to identify any benefit from this treatment, as well as any potential side effects, more quickly. Hopefully that will help us in the summer and fall, and next winter, be more specific with the way we use this potential treatment.”
Donors needed
The plasma that UAB has used comes from a local blood bank — the hospital has partnered with LifeSouth and the Red Cross.
“We put in requests for the blood samples we need to match to the patient,” Heath said. Just like typical blood transfusions, convalescent plasma must match the recipient’s blood type. The good news is that a single donation should be able to be used to treat two patients, Heath says.
“We have referred about eight to 10 COVID-recovered patients to our local blood banks with help from Audrey Lloyd, a UAB Infectious Disease fellow, and are working on expanding the supply of plasma to treat COVID patients,” Heath said. “But we need more donors.”
Donors must have a confirmed diagnosis of COVID-19 and have been symptom-free for 28 days.
“Most people who are interested in donating plasma will probably be eligible,” Heath said.
Two new studies starting soon — including convalescent plasma as prevention
Heath also is the principal investigator on two new convalescent plasma therapy studies that will open at UAB in the next few weeks. Both are in collaboration with Johns Hopkins University, she says.
“One is treatment of outpatients with COVID-19, and the other is trying to prevent COVID-19 in people who have been exposed,” she said. This “post-exposure prophylaxis” study, Heath said, “means you’ve been exposed to someone with COVID-19 for a long period of time — someone in your house, for example, and you haven’t been wearing a mask and are susceptible to getting COVID. We would treat you with the plasma in the hope this would prevent you from developing the symptoms related to COVID infection.”
The goal, Heath says, is to quickly enroll participants in both those studies. Although the studies will last for 12-16 months, “we will have pre-defined timepoints that allow us to look at the data along the way.”
Although convalescent plasma is a new idea to most people, “we have a long history of treating people with intravenous antibodies,” Heath said. “People in immunocompromised states often receive what is called IV IG — intravenous immunoglobulin. They are getting antibodies from other people to keep their immune systems strong. That has a long and safe history. This time, we’re just saying your immunoglobulin has to come from someone who has recovered from COVID-19, and that protection may be transferrable.”
Research leads the way
While Heath and McCarty treat patients in the hospital, Heath and a research collaborator are working in the lab to better understand the mechanisms involved. Randall Davis, M.D., professor in the UAB Division of Hematology and Oncology, is studying the quality of the donor’s antibody response as a factor in treatment success.
“The science that goes on behind the scenes in these types of clinical trials is very important,” Heath said. “That provides the building blocks we need as we are trying to understand how to make a vaccine or new therapies. As we learn more about these treatments, we can try to duplicate the best antibody response either through a vaccine or through COVID-specific monoclonal antibody development.”
“We want to do this work not only for our patients but also for the benefit of many more people,” Heath said. “We will be able to understand the benefits and risks and find answers much faster to improve the lives of those affected by COVID-19.”
(Courtesy of UAB)
