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CytoDyn Inc. – Leronlimab (severe)

Leronlimab (PRO 140) is a CCR5 antagonist with the potential for multiple therapeutic indications, such as HIV, cancer, and unwelcome immune reactions [1].

The cytokine storm observed in patients with COVID-19 promotes the development of acute respiratory distress syndrome (ARDS). A distinctive feature of ARDS is the accumulation of neutrophils within the lungs. Leronlimab (PRO 140) can potentially inhibit the migration of regulatory T cells into the damaged tissue, which can modulate the innate immune response against pathogens and, most importantly, mitigate the migration of macrophages and the release of pro-inflammatory cytokines into the lungs. Following compassionate care treatment of critically ill COVID-19 patients with the CCR5-blocking antibody leronlimab, complete CCR5 receptor occupancy on macrophage and T cells, rapid reduction of plasma IL-6, restoration of the CD4/CD8 ratio, and a significant decrease in SARS-CoV-2 plasma viremia were observed [2].

CytoDyn Inc. has initiated a Phase 2b/3, randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of Leronlimab in 390 patients with severe or critical COVID-19. The estimated primary completion date is December 31, 2020, while full results are expected in April 2021 [3].


  1. Hutchings, C. J. (2020). A review of antibody-based therapeutics targeting G protein-coupled receptors: an update. Expert Opinion on Biological Therapy, 1-11.
  2. Disruption of the CCL5/RANTES-CCR5 Pathway Restores Immune Homeostasis and Reduces Plasma Viral Load in Critical COVID-19 (preprint)
  3. Study to Evaluate the Efficacy and Safety of Leronlimab for Patients With Severe or Critical Coronavirus Disease 2019 (COVID-19)