Early plasma therapy may help prevent severe COVID-19 in patients over age 65: study

TORONTO -- A new study has found that administering convalescent plasma with a high concentration of antibodies against COVID-19 early on in mildly ill older adults may help reduced the progression of the disease.

The study, conducted by Argentina-based non-profit Fundación Infant, found that convalescent plasma therapy could "significantly reduce" the need for oxygen support among COVID-19 patients over 65 years old if administered within 72 hours after the onset of symptoms.

Lead investigator of the study, Dr. Fernando Polack, said in a press release the findings suggest a new approach for the treatment of older COVID-19 patients and could help address an "important gap" in the therapies currently available.

"There is a paucity of therapies today to prevent progression of mild cases to severe illness and no clear pathway for keeping these patients out of hospitals, where capacity continues to be stretched. Our results provide a roadmap for an early intervention among individuals at higher risk, allowing us to expect a better prognosis for patients while reducing the need for oxygen support and hospitalization," Polack said.

The findings were published Wednesday in the New England Journal of Medicine.

Convalescent plasma is a century-old medical concept that uses the protein-rich blood of a recovered patient as a treatment for sick patients, providing antibodies to fight the virus. It was previously used during the Ebola, MERS and SARS outbreaks.

While convalescent plasma has previously been studied to help treat the progression of early coronavirus infections, attempts to treat older, hospitalized COVID-19 patients with the therapy have been unsuccessful. Researchers behind this new study suggest that is because the plasma needs to be administered earlier in the course of illness and at a higher concentration of antibodies.

The study says that if these conditions are met, plasma therapy "could decrease the possibility that patients will require oxygen by half."

TRIAL DESIGN, OVERSIGHT AND OUTCOMES

The study was conducted as a "randomized, double-blind, placebo-controlled trial" between June 4 and Oct. 25, 2020. The study looked at 160 coronavirus patients who were age 75 or older with no coexisting health conditions, or between 65 and 74 years of age with at least one pre-existing condition.

According to the press release, an independent data and safety monitoring committee oversaw the study, and it was funded by a grant from the Bill & Melinda Gates Foundation and the Fundación Infant Pandemic Fund.

Eligible patients were given 250 ml of convalescent plasma with an IgG titer of 1:1000 or higher against the SARS-CoV-2 spike protein, or a placebo less than 72 hours after the onset of COVID-19 symptoms. The trial used convalescent plasma obtained from volunteers that have recovered from COVID-19 infections.

Of the 160 patients studied, researchers found that severe respiratory disease developed in 13 of 80 patients (16 per cent) who received convalescent plasma and in 25 of 80 patients (31 per cent) who received the placebo.

According to the study, the development of severe respiratory disease in the convalescent plasma group was 15 days longer than that in the placebo group.

Researchers reported that administering convalescent therapy within 72 hours of COVID-19 diagnosis reduced the risk of progression to severe respiratory disease by 48 per cent, while plasma with IgG titers of 1:3200 or higher reduced the risk of severe COVID-19 by 73 per cent.

The study noted that the administration of convalescent plasma was "not associated with any solicited adverse events" or any "serious side effects." However, additional clinical trials to support the efficacy and safety of the treatment are ongoing.

Researchers say their findings "underscore the need to return to the classic approach of treating acute viral infections early" as access to convalescent plasma is easy and affordable in many low and middle-income countries struggling with COVID-19 outbreaks and hospital capacity.

With a per-patient cost of US$186.25 for plasma infusion in Buenos Aires, the study notes that convalescent plasma could be a "potentially inexpensive alternative" to other therapies in helping treat COVID-19.

Dr. Keith Klugman, director of the Pneumonia Program at the Bill & Melinda Gates Foundation, said in the release that plasma therapy will also aid these regions who may not receive vaccines for some time.

"Effective ways that can be made available quickly to prevent the hospitalization of COVID-19 patients are critical to saving lives because it will take some time for new vaccines to reach everyone who needs them," Klugman said.

"In addition to indicating the efficacy of a tool that could be implementable and affordable in lower-income countries, the study provides key insights about the immune response to COVID-19 that could help with development of other medical interventions," he added.

Convalescent plasma is currently not available in Canada as research continues.