Study shows that 19 out of 25 COVID-19 patients improved with convalescent plasma treatment

reviewed by Emily Henderson, B.Sc.May 13, 2020

The first results of the country’s convalescent plasma transfusion trial were published, showing that 19 of 25 patients improved with treatment, and 11 were discharged from the hospital. On March 28, the Houston Methodist became the first academic medical center in the nation to transfuse plasma from recovered patients with COVID-19 to two critically ill patients.

With no adverse side effects caused by plasma transfusion, the study concluded that convalescent plasma is a safe treatment option for patients with severe COVID-19 disease. To date, this is the largest cohort in the world evaluated for outcomes related to convalescent plasma transfusion for COVID-19.

While medical scientists around the world rushed to test new drugs and treatments against the COVID-19 killer virus, convalescent serum therapy emerged as one of the most promising strategies. With no proven treatments or cures for COVID-19 patients, now was the time in our history to move fast. “

James M. Musser, M.D., Ph.D., Chairman, Houston Methodist Department of Pathology and Genomic Medicine

The patients were first treated under the FDA Emergency Use Guidelines (eIND) and then received FDA approval on April 3 to open the trial to more patients as a new investigational drug (IND). This extraordinarily fast FDA approval opened access to convalescent plasma treatment for patients with COVID-19.

The centennial therapeutic approach dates back to at least 1918 to combat the Spanish flu and, more recently, was used with some success during the 2003 SARS pandemic, the 2009 H1N1 influenza pandemic, and the 2015 Ebola outbreak in Africa. After an early study in the COVID-19 pandemic where a handful of critically ill patients in China showed improvement. An interdisciplinary team of Houston Methodist medical scientists and health workers quickly targeted the COVID-19 virus with convalescent serum therapy.

Given the urgency of finding effective treatments for COVID-19, a preliminary report has been released that has not yet been peer-reviewed on the prepress server. medRxiv. The manuscript, titled “Treatment of COVID-19 Patients with Convalescent Plasma in Houston, Texas,” has been submitted for peer review to a leading medical journal. This preprint is not the final version of the article. Musser is the corresponding author in the study. Eric Salazar, M.D., Ph.D., an assistant professor of pathology and genomic medicine at the Houston Methodist Research Institute, is the lead investigator who led the project to treat critically ill patients with COVID-19 with convalescent plasma.

Additional findings during this trial revealed that the results of plasma therapy patients were very similar to the recently published results of patients treated with compassionate use of the antiviral drug Remdesivir. The research team also concluded that any observed complications were consistent with the reported findings for COVID-19 disease progression and not caused by plasma transfusions. The overall study findings were consistent with several other small case studies on the use of convalescent plasma for severe COVID-19 that have been recently reported.

Finally, although convalescent plasma therapy administered first-line by the Houston Methodist was implemented for emergency treatment, the study authors acknowledge the significant need for controlled clinical trials to determine their therapeutic efficacy. A randomized controlled trial is currently being considered by the Houston Methodist, where they would also look more closely at variables such as timing of transfusion after onset of symptoms, number and volume of transfusions adjusted for patient biometry, antibody levels in the donor plasma and numerous other parameters necessary to effectively evaluate how to optimize this therapy. This would help to address some questions, even if patients would have better results if plasma transfusions were administered before the onset of symptoms.

Not all plasma recipients transfused so far at Houston Methodist were part of this first trial. Since the end of March, when the first patients received a convalescent plasma infusion, the Houston Methodist has treated 74 critically ill patients with COVID-19, 50 of whom have been discharged from the hospital and are recovering. More than 150 recovered COVID-19 infected people donated their plasma, and many of them continued to do so frequently.