Treatment with convalescent plasma vastly improved the survival rate of patients hospitalized for COVID-19 who also had hematologic malignances that compromise the immune system, according to new data released by the COVID-19 and Cancer Consortium (CCC19).
Patients who received convalescent plasma from donors who had recovered from COVID-19 had a death rate of 13.3% compared to 24.8% for those who did not receive it.
The difference was more striking with patients admitted to intensive care units, where patients treated with convalescent plasma had a death rate of 15.8% compared to 46.9% for those who weren't.
The researchers released the study's findings ahead of publication in a peer-reviewed medical journal because of its potential clinical implications and the urgency of sharing information about effective COVID-19 treatments.
"Despite the inevitable limitations of retrospective data, gathering enough case reports was really only possible through a large and comprehensive registry such as ours. We find these results compelling and certainly hope that they will be quickly investigated in a prospective clinical trial," said corresponding author Jeremy Warner, MD, MS, FASCO, associate professor of Medicine at Vanderbilt University Medical Center (VUMC).
The study compared the 30-day mortality of hospitalized adults with both a hematologic malignancy and a COVID-19 diagnosis from 71 medical centers that participate in the international CCC19 consortium. The analysis was conducted on 143 patients who received convalescent plasma and 823 who did not
Hematologic malignancies, such as chronic lymphocytic leukemia and multiple myeloma, are associated with defects in immunity, which can be exacerbated with treatments for the cancers, putting patients with these blood cancers at additional risk for infections and infectious disease severity. Prior small case reports had noted improvements when these patients have been administered convalescent plasma as a treatment for COVID-19, but this study is the first retrospective cohort study to indicate a benefit when compared to non-recipients.
"Given that patients with hematologic malignancies have consistently higher mortality rates from COVID-19, we suspect our findings, along with other similar cases, support the biological plausibility of using convalescent plasma to improve survival in patients with hematologic cancers. Further research will study this hypothesis generating data and will likely change treatment practice," said the study's lead author, Michael Thompson, MD, PhD, an oncologist and hematologist with Advocate Aurora Health and Advocate Aurora Research Institute.
Jeffrey Henderson, MD, PhD, associate professor of Medicine and Molecular Microbiology at Washington University, contributed equally as a lead author of the study.
The COVID-19 and Cancer Consortium (CCC19) was formed in early 2020 to rapidly collect data as part of an effort to understand the unique effects the coronavirus has on cancer patients. Its genesis began with a Twitter exchange, and the study on convalescent plasma also originated with a Twitter discussion between Thompson and co-author Michael Joyner, professor of Anesthesiology at the Mayor Clinic, who is leading a national program sponsored by the U.S. government to coordinate the collection and distribution of COVID-19 convalescent plasma for the treatment of individuals with severe or life-threatening disease.
Todd Rice, MD, MSc, associate professor of Medicine at VUMC, and Wesley Self, MD, MPH, associate professor of Emergency Medicine, are leading another national program -- a randomized controlled trial to test whether convalescent plasma can help hospitalized patients with COVID-19. The research is funded by a $34 million grant from the National Center for Advancing Translational Sciences, part of the National Institutes of Health.
The trial, called Passive Immunity Trial for Our Nation (PassItOn) received initial support from the Dolly Parton COVID-19 Research Fund.
"These results from the CCC19 study on patients with hematologic malignancies are really interesting and open the possibility that benefit from convalescent plasma may vary depending on underlying medical conditions," said Rice.
Self added: "These results will help us understand which types of patients may benefit from COVID-19 convalescent plasma and how to perform subgroup analyses in ongoing trials, including PassItOn."
PassItOn is one of two clinical trials of convalescent plasma funded through Operation Warp Speed, a collaborative initiative across federal agencies to advance development, manufacturing and distribution of COVID-19 vaccines, therapeutics and diagnotics.
"It is scientifically very satisfying to demonstrate that the idea of using sera from the convalescent patients that was probably first used during the 1916 New York outbreak of poliomyelitis, and then also during the 1918 Spanish influenza, is so useful in saving lives during COVID-19, the first great pandemic of this century," said Sanjay Mishra, PhD, MS, a staff scientist at VUMC, project manager of CCC19 and a co-author of the study.
CCC19 participants include cancer centers across the North and South America. Vanderbilt-Ingram Cancer Center, Advocate Aurora Health in Wisconsin and Illinois, Sylvester Comprehensive Cancer Center in Miami, Fred Hutchinson Cancer Research Center in Seattle and Dana-Farber Cancer Institute in Boston are the five founding institutional members. For more information about CCC19, visit https://ccc19.org.