Fig. 1: RMC-113 inhibits SARS-CoV-2 infection in vitro and in human ALOs with a high genetic barrier to resistance.

a Chemical structure of RMC-113. b Rescue assay for virus-induced cell lethality. RMC-113 (10 μM) was incubated with Vero E6-eGFP cells for 20 h followed by SARS-CoV-2 infection. eGFP signal measured at 96 hpi indicates cell survival. c and d Fluorescence images (c) and corresponding graph (d) of Vero-eGFP cells rescued from SARS-CoV-2-induced lethality by RMC-113 (Belgium-GHB-03021 strain, MOI = 0.05). Original magnification, ×5 (c). e and j, Dose response to RMC-113 of SARS-CoV-2 infection [black, USA-WA1/2020 strain, MOI = 0.05 (e), 1 (j)] and cell viability (blue) in Calu-3 cells (e) or ALO-derived monolayer supernatants (j) via plaque and alamarBlue assays at 24 (e) or 48 (j) hpi, respectively. f and i, Schematics of the experiments shown in g (f) and j, k, l (i), respectively. Figure was created in BioRender. Karim, M. (2025) https://biorender.com/2yx5sx9. g, Vero E6-TMPRSS2 cells were infected with rSARS-CoV-2-nLuc virus (MOI = 0.05) and passaged daily under RMC-113 (0.1–0.3 μM) or DMSO over nine passages. Viral titers were measured by plaque assays. h, Dose response to RMC-113 of rSARS-CoV-2-nLuc virus harvested after nine passages under RMC-113 or DMSO via luciferase assays. k Dose response to RMC-113 of SARS-CoV-2 (MOI = 1) nucleocapsid copy number in ALO lysates measured by RT-qPCR assays at 48 hpi. l Confocal IF microscopy images of F-actin (violet), nucleocapsid (green), and DAPI (blue) in uninfected and SARS-CoV-2–infected ALOs, pretreated with DMSO or RMC-113 (5 μM) at 24 hpi. Representative merged images at x40 magnification are shown. Scale bars: 50 μm. Data shown are representative of independent experiments (c, d, j, l) or represent combined results from two (n = 2; e, g, h) or three (n = 3; k) independent experiments. Data in e, h, j, and k are relative to DMSO. Means ± SD are shown. Source data are provided as a Source Data file.