ABSTRACT
BackgroundEnisamium (trade name Amizon(R) MAX) is an orally available therapeutic that inhibits influenza A virus and SARS-CoV-2 replication and improves influenza patient recovery. We aimed to evaluate the clinical efficacy of enisamium treatment combined with standard care compared to standard care plus treatment with a placebo control in adult, hospitalized patients with moderate COVID-19 requiring external oxygen. This trial was registered with ClinicalTrials.gov under NCT04682873. MethodsThe study was a phase three, multi-center, double-blind, randomized, placebo-controlled trial conducted in 14 clinical centers. Hospitalized patients aged [≥]18 years with laboratory-confirmed SARS-CoV-2 infection were eligible. Patients were randomly assigned to receive either enisamium (500 mg per dose, 4 times a day) or a placebo. The treatment lasted [≤]7 days in case of early discharge from the hospital, or loss of the patients ability to swallow due to the need for ventilation. All patients received standard of care as deemed necessary by the investigator and the health status of each patient. All patients received standard of care as deemed necessary by the investigator and each patients health status. The primary outcome was an improvement of at least two points on an 8-point, modified WHO severity rating (SR) scale within 29 days of randomization. The primary and safety outcomes were analyzed in accordance to the intention-to-treat (ITT) principle. FindingsA total of 592 patients were enrolled and randomized between May 2020 and March 2021. Only patients with a baseline SR of 4 (285 subjects or 48.1%) were included in the ITT analysis. Patients with a baseline SR of 5 were excluded as the interim analysis did not show relevant differences between the enisamium group and placebo in this sub-group. The patients with a baseline SR of 4 were divided into two groups: 142 (49.8%) were assigned to the enisamium group and 143 (50.2%) to the placebo group. No differences were observed between the safety or patient tolerability profiles of the enisamium and placebo treatment. Analysis of the ITT population showed that if patients were treated within 4 days of the onset of COVID-19 symptoms, the median time to improvement was 8 for the enisamium group and 13 days for the placebo group (p = 0.0051). For patients treated within 7 days of the onset of COVID-19 symptoms, the median time to improvement was 10 days for the enisamium group and 11 days for the placebo group (p = 0.0035). Comparison of groups using a stratified one-sided Logrank criterion (adjustment using stratification by age categories: "<40 years", "40-<65 years" and "[≥]65 years") showed statistically significant differences between the groups (p = 0.00945, one-sided). InterpretationEnisamium is safe to use in COVID-19 patients. In COVID-19 patients that did not require supplementary oxygen (SR = 5), standard treatment was sufficient to aid recovery and enisamium did not offer significant clinical benefits. However, we found that standard care combined with enisamium offers a significant clinical benefit when given to patients with moderate COVID-19 requiring supplementary oxygen (SR = 4), if enisamium is given within 7 days of the onset of symptoms. These data suggest that enisamium therapy can be used as therapy against SARS-CoV-2 infection in these patients. FundingFarmak JSC, Wellcome Trust, and Royal Society.
ABSTRACT
Pandemic SARS-CoV-2 causes a mild to severe respiratory disease called Coronavirus Disease 2019 (COVID-19). Control of SARS-CoV-2 spread will depend on vaccine-induced or naturally acquired protective herd immunity. Until then, antiviral strategies are needed to manage COVID-19, but approved antiviral treatments, such as remdesivir, can only be delivered intravenously. Enisamium (laboratory code FAV00A, trade name Amizon(R)) is an orally active inhibitor of influenza A and B viruses in cell culture and clinically approved in countries of the Commonwealth of Independent States. Here we show that enisamium can inhibit SARS-CoV-2 infections in NHBE and Caco-2 cells. In vitro, the previously identified enisamium metabolite VR17-04 directly inhibits the activity of the SARS-CoV-2 RNA polymerase. Docking and molecular dynamics simulations suggest that VR17-04 prevents GTP and UTP incorporation. To confirm enisamiums antiviral properties, we conducted a double-blind, randomized, placebo-controlled trial in adult, hospitalized COVID-19 patients, which needed medical care either with or without supplementary oxygen. Patients received either enisamium (500 mg per dose) or placebo for 7 days. A pre-planned interim analysis showed in the subgroup of patients needing supplementary oxygen (n = 77) in the enisamium group a mean recovery time of 11.1 days, compared to 13.9 days for the placebo group (log-rank test; p=0.0259). No significant difference was found for all patients (n = 373) or those only needing medical care (n = 296). These results thus suggest that enisamium is an inhibitor of SARS-CoV-2 RNA synthesis and that enisamium treatment shortens the time to recovery for COVID-19 patients needing oxygen. Significance statementSARS-CoV-2 is the causative agent of COVID-19. Although vaccines are now becoming available to prevent SARS-CoV-2 spread, the development of antivirals remains necessary for treating current COVID-19 patients and combating future coronavirus outbreaks. Here, we report that enisamium, which can be administered orally, can prevent SARS-CoV-2 replication and that its metabolite VR17-04 can inhibit the SARS-CoV-2 RNA polymerase in vitro. Moreover, we find that COVID-19 patients requiring supplementary oxygen, recover more quickly than patients treated with a placebo. Enisamium may therefore be an accessible treatment for COVID-19 patients.
