A Randomised -Controlled Phase 2 trial of Molnupiravir in Unvaccinated and Vaccinated Individuals with Early SARS-CoV-2

BackgroundMolnupiravir was licensed for treating high-risk patients with COVID-19 based on data from unvaccinated adults. AGILE CST-2 (NCT04746183) Phase II reports safety and virological efficacy of molnupiravir in vaccinated and unvaccinated individuals. MethodsAdult out-patients with PCR-confirmed SARS-CoV-2 infection within five days of symptom onset were randomly assigned 1:1 to receive molnupiravir (800mg twice daily for five days) or placebo. The primary outcome was time to swab PCR-negativity, compared using a Bayesian model for estimating the probability of a superior virological response (Hazard Ratio>1) for molnupiravir over placebo. Secondary outcomes included change in viral titre at day 5, safety and tolerability, clinical progression and patient reported outcome measures. We analysed outcomes after the last participant reached day 29. FindingsOf 180 participants randomised (90 molnupiravir, 90 placebo), 50% were vaccinated. Infections with SARS-CoV-2 variants Delta (40%), Alpha (21%), Omicron (21%) and EU1 (16%) were represented. The median time to negative-PCR was 8 versus 11 days for molnupiravir and placebo (HR=1{middle dot}30, 95% CrI 0{middle dot}92-1{middle dot}71, p=0{middle dot}07 by Logrank and p=0{middle dot}03 by Breslow-Gehan tests). Although small numbers precluded subgroup analysis, no obvious differences were observed between vaccinated and unvaccinated participants. Using a two-point prior the probability of molnupiravir being superior to placebo (HR>1) was 75{middle dot}4%, which was just below our defined threshold of 80% for establishing superiority. Using an uninformative continuous prior, the probability of HR>1 was 94{middle dot}7%. As an exploratory analysis, the change in viral titre on day 5 (end of treatment) was significantly greater with molnupiravir compared with placebo. A total of 4 participants reported severe adverse events (grade 3+), 3 of whom were in the placebo arm. InterpretationWe found molnupiravir to be well-tolerated, with evidence for high probability of antiviral efficacy in a population of vaccinated and unvaccinated individuals infected with a broad range of viral variants. FundingFunded by Ridgeback Biotherapeutics and UK National Institute for Health and Care Research infrastructure funding. The AGILE platform infrastructure is supported by the Medical Research Council (grant number MR/V028391/1) and the Wellcome Trust (grant number 221590/Z/20/Z).

Pharmacokinetics of β-d-N4-hydroxycytidine, the active metabolite of prodrug molnupiravir, in non-plasma compartments of patients with SARS-CoV-2 infection

{beta}-d-N4-hydroxycytidine (NHC), the parent nucleoside of molnupiravir, a COVID-19 antiviral, was quantified at sites of SARS-CoV-2 transmission in twelve patients enrolled in AGILE CST-2 (NCT04746183). Saliva, nasal and tear concentrations were 3, 21 and 22% that of plasma. Saliva and nasal NHC concentrations were significantly correlated with plasma (p<0.0001).

An open label, adaptive, phase 1 trial of high-dose oral nitazoxanide in healthy volunteers: an antiviral candidate for SARS-CoV-2

Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe COVID-19, but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is an FDA approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modelling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase 1 trial in healthy adult participants was undertaken with high dose nitazoxanide. Participants received 1500mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose and schedule. Intensive pharmacokinetic sampling was undertaken day 1 and 5 with Cmin sampling on day 3 and 7. Fourteen healthy participants were enrolled between 18th February and 11th May 2021. All 14 doses were completed by 10/14 participants. Nitazoxanide was safe and well tolerated with no significant adverse events. Moderate gastrointestinal disturbance (loose stools) occurred in 8 participants (57.1%), with urine and sclera discolouration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on first dose and maintained throughout. Nitazoxanide administered at 1500mg BID with food was safe and well tolerated and a phase 1b/2a study is now being initiated in COVID-19 patients.

Optimal dose and safety of molnupiravir in patients with early SARS-CoV-2: a phase 1, dose-escalating, randomised controlled study

BackgroundAGILE is a phase Ib/IIa platform for rapidly evaluating COVID-19 treatments. In this trial (NCT04746183) we evaluated the safety and optimal dose of molnupiravir in participants with early symptomatic infection. MethodsWe undertook a dose-escalating, open-label, randomised-controlled (standard-of-care) Bayesian adaptive phase I trial at the Royal Liverpool and Broadgreen Clinical Research Facility. Participants (adult outpatients with PCR-confirmed SARS-CoV-2 infection within 5 days of symptom onset) were randomised 2:1 in groups of 6 participants to 300mg, 600mg and 800mg doses of molnupiravir orally, twice daily for 5 days or control. A dose was judged unsafe if the probability of 30% or greater dose-limiting toxicity (the primary outcome) over controls was higher than 25%. Secondary outcomes included safety, clinical progression, pharmacokinetics and virologic responses. ResultsOf 103 volunteers screened, 18 participants were enrolled between 17 July and 30 October 2020. Molnupiravir was well tolerated at 400, 600 or 800mg doses with no serious or severe adverse events. Overall, 4 of 4 (100%), 4 of 4 (100%) and 1 of 4 (25%) of the participants receiving 300, 600 and 800mg molnupiravir respectively, and 5 of 6 (83%) controls, had at least one adverse event, all of which were mild ([≤]grade 2). The probability of [≥]30% excess toxicity over controls at 800mg was estimated at 0.9%. ConclusionMolnupiravir was safe and well tolerated; a dose of 800mg twice-daily for 5 days was recommended for Phase II evaluation.