Sarilumab plus standard of care vs standard of care for the treatment of severe COVID-19: a phase 3, randomized, open-labeled, multi-center study (ESCAPE study).

Background: Among interleukin-6 inhibitors suggested for use in COVID-19, there are few robust evidences for the efficacy of sarilumab. Herein, we evaluated the efficacy and safety of sarilumab in severe COVID-19. Methods: In this phase 3, open-labeled, randomized clinical trial, conducted at 5 Italian hospitals, adults with severe COVID-19 pneumonia (excluding mechanically ventilated) were randomized 2:1 to receive intravenous sarilumab (400 mg, repeatable after 12 h) plus standard of care (SOC) (arm A) or to continue SOC (arm B). Randomization was web-based. As post-hoc analyses, the participants were stratified according to baseline inflammatory parameters. The primary endpoint was analysed on the modified Intention-To-Treat population, including all the randomized patients who received any study treatment (sarilumab or SOC). It was time to clinical improvement of 2 points on a 7-points ordinal scale, from baseline to day 30. We used Kaplan Meier method and log-rank test to compare the primary outcome between two arms, and Cox regression stratified by clinical center and adjusted for severity of illness, to estimate the hazard ratio (HR). The trial was registered with EudraCT (2020-001390-76). Findings: Between May 2020 and May 2021, 191 patients were assessed for eligibility, of whom, excluding nine dropouts, 176 were assigned to arm A (121) and B (55). At day 30, no significant differences in the primary endpoint were found (88% [95% CI 81-94] in arm A vs 85% [74-93], HR 1.07 [0.8-1.5] in arm B; log-rank p = 0.50). After stratifying for inflammatory parameters, arm A showed higher probability of improvement than B without statistical significance in the strata with C reactive protein (CRP) < 7 mg/dL (88% [77-96] vs 79% [63-91], HR 1.55 [0.9-2.6]; log-rank p = 0.049) and in the strata with lymphocytes <870/mmc (90% [79-96]) vs (73% [55-89], HR 1.53 [0.9-2.7]; log-rank p = 0.058). Overall, 39/121 (32%) AEs were reported in arm A and 14/55 (23%) in B (p = 0.195), while serious AEs were 22/121 (18%) and 7/55 (11%), respectively (p = 0.244). There were no treatment-related deaths. Interpretation: The efficacy of sarilumab in severe COVID-19 was not demonstrated both in the overall and in the stratified for severity analysis population. Exploratory analyses suggested that subsets of patients with lower CRP values or lower lymphocyte counts might have had benefit with sarilumab treatment, but this finding would require replication in other studies. The relatively low rate of concomitant corticosteroid use, could partially explain our results. Funding: This study was supported by INMI "Lazzaro Spallanzani" Ricerca Corrente Linea 1 on emerging and reemerging infections, funded by Italian Ministry of Health.