Yet other research that was presented at the American Society of Hematology (ASH) Annual Meeting in December 2020 made the case for giving convalescent plasma to hospitalized COVID-19 patients.3 Of 15 patients, including 6 with hematological malignancies, all showed improvement after receiving the antibodies. The team from Tulane University in New Orleans, Louisiana, also found evidence for a correlation that’s becoming standard practice — those who received it earlier showed the best improvement.
The fact that there is a growing number of studies showing a benefit of plasma for COVID-19 patients who have blood cancers isn’t surprising for many oncologists like S. Vincent Rajkumar, MD, a Mayo Clinic professor of medicine who was not part of team that conducted the review study that came out as a preprint in November 2020. It makes sense that COVID-19 patients with myeloma and leukemia would respond well to convalescent plasma therapy because they have low antibody levels to begin with due to their cancer status or chemotherapy treatment. “I would have anticipated that they would have responded even better than the general population because they have few other ways of making antibodies,” he said.
Dr Rajkumar, who’s also editor-in-chief of Blood Cancer Journal, said he hopes the emerging data will help convalescent plasma shed its image as a “controversial treatment.” Not only is there more specialized evidence for cancer patients, improvements in administering the treatment is helping shape the medical field’s view of it. “In the early days of pandemic, much of [the] plasma wasn’t tested to see if it had enough antibody levels,” he said, “It was the luck of the draw. Some would get a batch with sufficient antibody levels, and some would get a batch with very low antibody levels, so it was hard to judge the benefit.” Now, the quality has been standardized, and physicians know to give it early. “That was an important learning curve,” he said.
For oncologists who are used to administering immunoglobulin replacement therapy to help patients with low levels of antibodies, giving them convalescent plasma feels like a logical next step, added Jeffrey P. Henderson, MD, PhD, associate professor of medicine and molecular microbiology at Washington University School of Medicine in St. Louis, Missouri. “It’s not a jump from what the usual practice is. It’s a familiar kind of intervention,” he said.
Yet the Mayo Clinic data are helpful to clinicians because they provide extra reassurance that the therapy won’t harm patients. Although more studies are being conducted around the world, Dr Henderson said enough evidence has accumulated for doctors to consider giving convalescent plasma to patients with hematologic malignancies.
Despite the consensus that giving the treatment earlier is better, the case reports also fill a critical knowledge gap by showing that patients are still likely to improve if they get it later than recommended. “This population might have a longer window to benefit,” said Dr Henderson.
Eventually, Dr Rajkumar predicted, monoclonal antibodies (mAbs) will supplant convalescent plasma to become the standard of care. In November 2020, the FDA authorized the emergency use of 2 kinds of these therapies for mild-to-moderate COVID-19 cases, yet the mAbs are not yet widely available. ”With monoclonal antibody therapy, you know the exact amounts that are being administered. And we have clear randomized controlled trial data on efficacy,” he said. “Convalescent plasma data is mostly from uncontrolled studies and case reports.”
In the meantime, Senefeld hopes his review paper will give clinicians data on convalescent plasma that they can discuss with patients. “When you approach a patient with an experimental therapy, it’s a daunting task,” he said. “We wanted to get this information out quickly so clinicians had a better understanding of the available literature describing the use of convalescent plasma and had something that could be shared with patients.”
- Senefeld JW, Klassen SA, Ford SK, et al. Therapeutic use of convalescent plasma in COVID-19 patients with immunodeficiency. medRxiv preprint. Published November 10, 2020. doi:10.1101/2020.11.08.20224790
- Simonovich VA, Burgos Pratx LD, Scibona P, et al. A randomized trial of convalescent plasma in Covid-19 severe pneumonia. New Eng J Med. Published November 24, 2020. doi:10.1056/NEJMoa2031304
- Ibrahim M, Pal P, Niu A, et al. COVID-19 convalescent plasma decreased oxygen requirement and hospital stay in COVID-19 hospitalized patients including those with hematological malignancies: a report of 16 patients. Presented at: the 62nd American Society of Hematology (ASH) Annual Meeting and Exposition; December 5-9, 2020. Abstract 101.