Real-world effectiveness of prophylactic tixagevimab-cilgavimab monoclonal antibodies on incidence and severity of COVID-19 infection in patients with cancer.

Abstract

e18843 Background: Mortality rate secondary to COVID-19 in patients with cancer is estimated to be > 10% after vaccination, with an increased risk of infection and hospitalization The FDA granted emergency use approval for pre-exposure prophylaxis with tixagevimab-cilgavimab (Evusheld)based on preliminary results from the PROVENT trial conducted before the emergence of the Omicron variant. However, there are limited real-world studies investigating the impact of Evusheld on COVID-19 in patients with cancer, especially after Omicron became the most common circulating variant in the US in Nov 2021. We assessed the impact of Evusheld on the incidence and severity of COVID-19 at our institution. Methods: We conducted a retrospective descriptive study in our institution on patients with cancer who received Evusheld between Dec 2021 and Mar 2022 with a 6 month follow-up. Primary outcome was incidence of COVID-19. Secondary outcomes included rate of hospitalization related to COVID-19 and associated mortality. Results: Of the 228 patients included in this study, 90% were White with a median age of 67 years, 67% had a hematologic malignancy, 98% were vaccinated against COVID-19, and 72.8% received the recommended 300mg dosing during the study period. Thirty-one patients (13.6%) developed COVID-19, with an average time to diagnosis of 43 days from receiving Evusheld, of whom 26 (83%) were symptomatic. Infected patients were of an average age of 60 years with a BMI of 26, and only a minority (3.2%) had prior COVID-19. Most had hematologic malignancies (77.4%), with the most common being non-Hodgkin lymphoma. Most were receiving chemotherapy (68%) at the time of diagnosis. Third of the affected patients received ani-CD20 treatment (32%). Most received only 150 mg dose (80.6%) of Evusheld. 8(33%) patients with hematological malignancy and 3 (42%) with solid malignancy received Paxlovid after diagnosis. All patients who had COVID-19 were previously vaccinated, with the majority receiving 3 doses (64.5%). Five (16%) patients were hospitalized for COVID-19, of whom 4 had hematological malignancy; one with hematological malignancy required mechanical ventilation and died. Conclusions: Overall, the incidence of COVID-19 following Evusheld was higher than in the PROVENT trial. This could be attributed to the ineffectiveness of Evusheld against new variants. Infections appeared to be more common and severe in patients with hematologic malignancies. [Table: see text]