Convalescent Plasma Therapy Linked to Potential Survival Benefit for Patients With Hematologic Cancers and COVID-19

The administration of convalescent plasma therapy was found to be associated with a survival benefit in patients with hematologic cancers and COVID-19, according to a cohort study published in JAMA Oncology.

Findings from the study indicated that within 30-days of COVID-19 diagnosis, 223 deaths (23.1%) occurred among the patient population. The crude mortality rate within 30 days of diagnosis was significantly lower among patients who received convalescent plasma (13.3%) compared with patients who didn’t receive convalescent plasma (24.8%). The association of improved 30-day mortality after treatment with convalescent plasma was found to be statistically significant after the research team adjusted the overall comparison (HR, 0.60; 95% CI, 0.37-0.97; P = .03) and the propensity score–matched comparison (HR, 0.52; 95% CI, 0.29-0.92; P = .03).

“This cohort study found that convalescent plasma therapy was associated with a survival benefit in patients with hematologic cancers and COVID-19,” wrote the investigators. “If this finding should hold up in prospective clinical trials, convalescent plasma would be, to our knowledge, the first COVID-19 intervention with a survival benefit in this high-risk population.”

The COVID-19 and Cancer Consortium seeks to understand the clinical impact of COVID-19 on patients with cancer. Investigators analyzed data from hospitalized adult patients who had a current or previous diagnosis of hematologic cancer and suspected or confirmed COVID-19.

Overall, 966 patients with a mean age of 65 years, of whom 55.8% were male, had a primary or secondary hematologic cancer and were evaluable based on eligibility criteria. The majority of patients had lymphoid malignancies (86.0%) while a minority of patients myeloid malignancies (14.7%). A total of 143 patients received convalescent plasma treatment, while 823 were enrolled in the untreated control cohort. Fifty-three percent of the population received systemic anticancer treatment within 3 months of COVID-19 diagnosis. Targeted therapies were the most commonly received treatment option for patients enrolled on the study.

Patients who received convalescent plasma were more likely to require aggressive care, with investigators noting that 53.1% required intensive care unit admission and 31.5% required mechanical ventilatory support. Additionally, complications such as bleeding (11.2%), sepsis (40.6%), respiratory failure (69.2%), and congestive heart failure (7.0%) were more frequent in those who received convalescent plasma.

For patients who were admitted to the intensive care unit (n = 338), the crude mortality rate among patients who received convalescent plasma was significantly lower than those who didn’t receive convalescent plasma for both the overall comparison (HR, 0.30; 95% CI, 0.16-0.56) and the propensity score–matched comparison (HR, 0.40; 95% CI, 0.20-0.80). The crude mortality rate was also significantly lower for patients who needed mechanical ventilatory support (n = 227) and received convalescent plasma in both the overall comparison (HR, 0.23; 95% CI, 0.10-0.50) and the propensity score–matched comparison (HR, 0.32; 95% CI, 0.14- 0.72).

There are several limitations associated with this research, specifically beginning with its retrospective design and the number of variables left unmeasured, including “the exact timing of convalescent plasma administration with respect to the date of COVID-19 diagnosis, the antibody titers and levels in the plasma that was administered, and whether repeat dosing was used.” Moreover, the investigative team suggests that results should be interpreted with caution due to the potential that residual confounding remains.

“Prospective randomized trials evaluating convalescent plasma in patients with hematologic cancers with attention to administration timing and consideration of repeated dosing are recommended,” the investigators concluded.

Reference

Thompson MA, Henderson JP, Shah PK, et al. Association of convalescent plasma therapy with survival in patients with hematologic cancers and COVID-1. JAMA Oncol. Published online ahead of print, June 17, 2021. doi:10.1001/jamaoncol.2021.1799