Temelimab versus placebo in patients with post-COVID condition

Introduction More than 400 million individuals are estimated to have been affected by post-COVID condition or long COVID. This condition can lead to significantly decreased quality of life and increased individual and societal costs. Temelimab, a monoclonal IgG4 backbone antibody targeting HERV-W ENV, may be a potential treatment for post-COVID. Methods In this randomized, double-blind trial, which consisted of a 24-week treatment period, we enrolled adults who had fatigue and persistent symptoms due to post-COVID and were positive for HERV-W-ENV. Participants were randomized (1:1) to receive 54 mg/kg Temelimab or placebo IV once monthly. The primary endpoint was the decline in fatigue (defined as a 3-point decrease on the PROMIS Fatigue SF 7a scale) from baseline to Week 24. Secondary endpoints included changes in cognition, anxiety, depression, functional impairment, quality of life, safety and tolerability of Temelimab. Results A total of 203 individuals participated in this study, 72% women, mean age 46 (standard deviation, SD 10) years. The mean initial PROMIS Fatigue SF 7a score was 26.8 (SD 3.4) in the Temelimab group and 27.1 (SD 3.8) in the placebo group. At 24 weeks, there was no difference between Temelimab (3.2 points decrease in the PROMIS score) and placebo (3.8 points decrease). Secondary outcomes also did not show differences between the Temelimab and placebo groups. Conclusion In adults with persistent symptoms due to post-COVID condition, the use of Temelimab did not show improvement in fatigue compared to placebo (Funded by GeNeuro SA; ClinicalTrials.gov number NCT05497089). Ethics and dissemination National authorities for clinical trials on medicinal products and ethical approval was obtained in all participating countries in Europe. Trial registration numbers ClinicalTrials.gov number (NCT05497089), EudraCT (2022-000618-32). Protocol version v5.0, date 23 February 2024; CCER Geneva IRB: 2022-00658.