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Cochrane COVID-19 Study Register
Study record
Mukae 2022First Published: 2022 May 26Updated Date: 2022 May 26

A Randomized Phase 2/3 Study of Ensitrelvir, a Novel Oral SARS-CoV-2 3C-like Protease Inhibitor, in Japanese Patients With Mild-to-Moderate COVID-19 or Asymptomatic SARS-CoV-2 Infection: results of the Phase 2a Part

  1. Study Type
  2. Interventional
  1. Study Aim
  2. Treatment and Management
  1. Study Design
  2. Parallel/Crossover
  1. Intervention Assignment
  2. Randomised
Reference record

A Randomized Phase 2/3 Study of Ensitrelvir, a Novel Oral SARS-CoV-2 3C-like Protease Inhibitor, in Japanese Patients With Mild-to-Moderate COVID-19 or Asymptomatic SARS-CoV-2 Infection: results of the Phase 2a Part

Mukae H, Yotsuyanagi H, Ohmagari N, Doi Y, Imamura T, Sonoyama T, Fukuhara T, Ichihashi G, Sanaki T, Baba K, Takeda Y, Tsuge Y, Uehara T
Unpublished article (preprint)
Report Results
For the treatment of coronavirus disease 2019 (COVID-19), antiviral agents that can achieve rapid severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reduction are warranted. This double-blind, phase 2a part of a phase 2/3 study assessed the efficacy and safety of ensitrelvir, a novel oral SARS-CoV-2 3C-like protease inhibitor, in Japanese patients with mild-to-moderate COVID-19 or asymptomatic SARS-CoV-2 infection. Sixty-nine patients enrolled from 56 sites were randomized (1:1:1) to orally receive 5-day ensitrelvir fumaric acid (375 mg on day 1 followed by 125 mg daily or 750 mg on day 1 followed by 250 mg daily) or placebo and followed up until day 28. The primary outcome was change from baseline in SARS-CoV-2 viral titer. A total of 16, 14, and 17 patients in the ensitrelvir 125 mg, ensitrelvir 250 mg, and placebo groups, respectively, were included in the intention-to-treat population (mean age: 38.8, 40.4, and 38.0 years, respectively). On day 4, the change from baseline in SARS-CoV-2 viral titer (log10 50% tissue culture infectious dose/mL) in patients with positive viral titer and viral RNA at baseline was greater with ensitrelvir 125 mg (mean [standard deviation], -2.42 [1.42]; P = 0.0712) and 250 mg (-2.81 [1.21]; P = 0.0083) versus placebo (-1.54 [0.74]), and ensitrelvir treatment reduced SARS-CoV-2 RNA by -1.4 to -1.5 log10 copies/mL versus placebo. All adverse events were mild to moderate. Ensitrelvir treatment demonstrated rapid SARS-CoV-2 clearance and was well tolerated in patients with mild-to-moderate COVID-19 or asymptomatic SARS-CoV-2 infection (Japan Registry of Clinical Trials identifier: jRCT2031210350). [Preprints are preliminary reports of work that have not been peer reviewed. Refer to the original preprint or preprint server for specific information about the individual preprint.]