Bamlanivimab/Etesevimab Associated With Increased 30-Day Risk of Hospitalisation, Death in Patients With SARS‑CoV‑2 P.1 Variant

July 13, 2021

By Shazia Qureshi

VIRTUAL -- July 13, 2021 -- In outpatients with the P.1 (Gamma) variant of severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) who were at high risk of disease progression, treatment with bamlanivimab plus etesevimab led to a higher 30-day risk of hospitalisation or death compared with treatment with casirivimab plus imdevimab, compared to an observational study presented at the 31st European Congress of Clinical Microbiology & Infectious Diseases (ECCMID).

“SARS-CoV-2 variants of concern are of public interest because of their extensive mutations in the spike protein, that could lead to antigenic changes detrimental to neutralising monoclonal antibodies therapies and vaccine protection,” explained Marco Falcone, MD, University of Pisa, Pisa, Italy. “In patients infected by the SARS-CoV-2 P.1 variant bamlanivimab/etesevimab should be avoided because of a high risk of failure.”

The current study included 165 outpatients from 2 Italian hospitals who were positive for SARS-CoV-2 between March 20 and May 10, 2021, and were at high risk for disease progression. The bamlanivimab/etesevimab combination was administered to 73 opatients, 53 of whom were diagnosed with the Alpha (B.1.1.7) variant and 20 with the Gamma (P.1) variant. The other 92 patients received the casirivimab/imdevimab combination (69 with the Alpha variant and 23 with the Gamma variant).

A one-time infusion with the neutralising monoclonal antibodies was administered within 10 days of symptom onset, and patients underwent polymerase chain reaction (PCR) testing for SARS-CoV-2 and a physical exam once a week for 4 weeks.

Among patients infected with the Gamma (P.1) variant, a higher proportion of those who had received bamlanivimab/etesevimab experienced hospitalisation or death within 30 days of treatment infusion -- the primary endpoint -- compared with patients who had received casirivimab/imdevimab (55% vs 17.4%; P = .013). However, among patients with the Alpha (B.1.1.7) variant, no differences were found between the 2 treatments for the primary endpoint (5.7% vs 4.3%; P = 1.0).

A multivariate Cox-regression analysis found 2 risk factors associated with reaching the primary endpoint: infection with the Gamma (P.1) variant (hazard ratio [HR] = 9.84; PP = .003).

“Knowing which variant of SARS-CoV-2 is the cause of a patient’s COVID-19 [coronavirus 2019] may allow for more appropriate use of therapy with neutralising monoclonal antibodies therapies,” said Dr. Falcone.
[Presentation title: Clinical Efficacy of Bamlanivimab/Etesevimab and Casirivimab/Imdevimab Against SARS-CoV-2 Variants of Concern. Abstract 4716]