Efficacy of Tixagevimab-Cilgavimab Prophylaxis for COVID-19 in Patients with Hematologic Cancer

Long-Acting Monoclonal Antibody Combination was Safe and Effective

By Peter A. McCullough, MD, MPH

My very frail patients with hematologic malignancies such as chronic myeloid and lymphocytic leukemias have asked me if there are safer alternatives than COVID-19 vaccination. This study by Salvini and colleagues demonstrated that fortunately later in the pandemic with the milder Omicron strains despite being highly prevalent, rarely resulted serious COVID-19 illness. The study group was 100% vaccinated with one of the failed vaccine products, however the time from the last injection was not reported and the authors failed to disclose prior infection as a proxy for natural immunity. The investigators must have lost faith in the vaccines and hence the decision to give the long-acting tixagevimab-cilgavimab monoclonal antibody combination.

“At data cutoff (March 1, 2023), the rate of breakthrough infections was 28 of 130 (21%) among patients exposed to tixagevimab-cilgavimab vs 28 of 74 (38%) in the control group (P = .01). The incidence of COVID-19 was 13.8 per 10000 person-days in the tixagevimab-cilgavimab group vs 28.0 in the control arm (hazard ratio [HR], 0.47; 95%CI, 0.27-0.81; P = .01). Administration of tixagevimab-cilgavimab was associated with a significant reduction in the incidence of severe or critical COVID-19 (1.4 vs 4.0 per 10 000 person days; HR, 0.18; 95% CI, 0.03-0.99; P = .0495). Need for hospitalization was also significantly lower in patients receiving prophylactic tixagevimab-cilgavimab (1.3 vs 4.0 per 10 000 person-days; HR, 0.19; 95% CI, 0.04-0.91; P = .04) (Table).”