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Researchers Expand Clinical Trials Investigating Convalescent Plasma Therapy for COVID-19

It’s hoped the long-used approach, which would use antibody-rich infusions, can either reduce disease symptoms or prevent infections after exposure to SARS-CoV-2

Parallel to COVID-19 vaccination efforts, physicians and researchers at UC San Diego Health, with collaborators across the country, are conducting a pair of clinical trials to assess whether convalescent plasma (CP) therapy can either mitigate symptoms in outpatients with the viral disease or perhaps prevent it after a known exposure.

plasma sample.

Convalescent plasma therapy uses the plasma portion of blood—a yellowish fluid consisting of water, salts and enzymes. The plasma is enriched with antibodies derived from COVID-19 survivors.

“Convalescent plasma has already been proven to be safe,” said Dr. Edward Cachay, principal investigator for the trial at UC San Diego assessing the prophylactic or prevention potential of CP. “Now, we want to test whether such a therapy, like vaccines, can protect you and others.”

In both randomized, double-blind clinical trials, participants will receive one intravenous infusion of either blood plasma containing high concentrations of antibodies for COVID-19 derived from survivors of the disease or a placebo plasma without COVID-19 antibodies. Participants will be monitored over four weeks for onset or progression of COVID-19, including symptom checks and laboratory testing for the virus and antibodies.

“We’ll also be looking for evidence of long-term immunity at three months after infusion in both those receiving convalescent or placebo plasma,” said Cachay, an infectious disease specialist at UC San Diego Health and professor of medicine at the School of Medicine.

Before the emergence of antibiotics, CP was frequently used to prevent and treat a host of bacterial and viral infections, including diphtheria, scarlet fever and pertussis. It was used during the 1918 influenza pandemic with reported good effect.

In general, CP treatment has proven safe, but its effectiveness has varied with disease and among individuals. Studies of CP therapies for Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS) and the 2009 H1N1 influenza showed measurable reductions of mortality (compared to placebo or no therapy), but efforts to treat Ebola virus infections during the 2014-16 outbreak in West Africa were inconclusive.

Both of the new clinical trials are nationwide, overseen by Johns Hopkins University researchers, with multiple trial sites. The trials are recruiting 1,100 participants. The prophylactic trial at UC San Diego Health launched in July 2020, and has enrolled 31 of the 151 participants recruited so far.

“We have learned from more than 400,000 transfusions of COVID-19 convalescent plasma that it is safe for most people and that the time and dose of infusion matters. There is emergent evidence that convalescent plasma works best when infused as early as possible in the disease process.

“There is no earlier stage than that of trying to stem coronavirus after a high-risk exposure. This is the basis of our post-exposure prophylaxis clinical trial. Our strategy seeks to prevent the exposed individual from becoming ill, and also prevent further COVID-19 transmission. Thus, we hope intervention effectively complements other efforts to curve down the COVID-19 pandemic.”

To qualify for the prevention trial, participants must be at least 18 years old, been exposed to COVID-19 within the previous 96 hours and not experiencing any known symptoms of the disease. You can also call 619-537-9426 to see if you qualify.

Enrolled participants will receive up to $575 in compensation over the course of trial participation.

Persons interested in participating in either of the trials should visit the COVID-19 Plasma Trial website or call (619) 537-9426 to take an eligibility survey and submit their contact information to the recruitment team.