Clinical Characteristics and Outcomes of COVID-19 Patients Receiving Compassionate Use Leronlimab.

BACKGROUND: Leronlimab, a monoclonal antibody blocker of CCR5 originally developed to treat HIV-1 infection, was administered as an open label compassionate use therapeutic for COVID-19. METHODS: 23 hospitalized severe/critical COVID-19 patients received 700mg leronlimab subcutaneously, repeated after seven days in 17/23 patients still hospitalized. 18/23 received other experimental treatments, including convalescent plasma, hydroxychloroquine, steroids, and/or tocilizumab. 5/23 received leronlimab after blinded placebo-controlled trials of remdesivir, sarilumab, selinexor, or tocilizumab. Outcomes and results were extracted from medical records. RESULTS: Mean age was 69.5±14.9 years. 20/23 had significant co-morbidities. At baseline, 22/23 were receiving supplemental oxygen (3/23 high flow, 7/23 mechanical ventilation). Blood showed markedly elevated inflammatory markers (ferritin, D-dimer, C-reactive protein) and elevated neutrophil:lymphocyte ratio. By day 30 after initial dosing, 17/23 were recovered, 2/23 were still hospitalized, and 4/23 had died. Of the 7 intubated at baseline, 4/7 were fully recovered off oxygen, 2/7 were still hospitalized, and 1/7 had died. CONCLUSIONS: Leronlimab appeared safe and well tolerated. The high recovery rate suggested benefit, and those with lower inflammatory markers had better outcomes. Some but not all patients appeared to have dramatic clinical responses, indicating that unknown factors may determine responsiveness to leronlimab. Routine inflammatory and cell prognostic markers did not markedly change immediately after treatment, although IL-6 tended to fall. In some persons C-reactive protein clearly dropped only after the second leronlimab dose, suggesting that a higher loading dose might be more effective. Future controlled trials will be informative.