Late versus early administration of convalescent plasma in hospitalized patients with covid-19: Results from the randomized open label clinical trial capsid

ABSTRACT

Background: Several observational studies suggested efficacy of COVID-19 convalescent plasma (CCP) but the results of several randomized clinical trials of CCP are not consistent. The trials differ in treatment schedules in terms of timing, volume and antibody content of CCP as well as enrolled patient populations and endpoints. The CAPSID was designed at the beginning of the pandemic and assessed the efficacy of neutralizing antibody containing high-dose COVID-19 convalescent plasma (CCP) in hospitalized patients with severe COVID-19. Methods: Patients (n=105) in 13 hospitals in Germany were randomized to either receive standard treatment and three units of CCP on days 1, 3 and 5 (total dose 846 ml) (n=53) or standard treatment alone (n=52). Patients in the control group with progress on day 14 could receive CCP (crossover group;n=7) on days 15, 17 and 19. The primary outcome was a dichotomous composite outcome of survival and no longer fulfilling criteria of severe COVID-19 on day 21. For Cross over patients a propensity matching with patients of the plasma group was performed. Results: Neutralizing antibodies were present at baseline in 18.2% of CCP and 19.2% of control group patients. In the ITT analysis the primary outcome occurred in 43.4% of patients in the CCP and 32.7% in the control group (p=0.32). The CCP group showed a trend for shorter times to clinical improvement (40 days, p=0.27) and discharge from hospital (20 days, p=0.24). Among those in the CCP group who received a higher or lower cumulative amount of neutralizing antibodies the primary outcome occurred in 56.0% and 32.1% of patients The high titer group showed significantly shorter intervals to clinical improvement or hospital discharge and a better overall survival (p=0.02). None of the patients in the crossover group (CG) achieved clinical improvement and survived. Comparing the CG to 14 CCP patients matched by baseline characteristics resulted in worse OS in the CG group (p=0.02) while comparison with 6 day 14 matched patients showed equal OS. Interpretation: CCP added to standard treatment did not result in a significant difference in the primary and secondary outcomes. A pre-defined subgroup analysis showed a signal of benefit for CCP among those who received a larger amount of neutralizing antibodies. A progress on day 14 is an indicator for poor outcome in COVID-19. Late administration of CCP is not supported by our results.