FLARE: Favipiravir +/- Lopinavir: A RCT of Early Antivirals

  • End date
    Dec 31, 2021
  • participants needed
  • sponsor
    University College, London
Updated on 8 May 2021
antiviral drugs


The current pandemic of SARS-CoV-2 causing COVID-19 disease is an unprecedented global emergency. COVID-19 appears to be a disease with an early phase where the virus replicates, coinciding with first presentation of symptoms, followed by a later 'inflammatory' phase which results in severe disease in some individuals. It is known from other rapidly progressive infections such as sepsis and influenza that early treatment with antimicrobials is associated with better outcome. Antiviral medications are most likely to be effective when administered soon after infection. There is therefore an urgent need to study subjects who have recently developed symptoms, or have recently been tested positive with or without symptoms, and who can be sampled frequently to understand changes in viral load. This cohort will allow us to collect detailed trajectory data on early disease and understand how pharmacological interventions may affect this. The objective of the FLARE trial is to assess whether early antiviral therapy with either favipiravir + Lopinavir/ritonavir (LPV/r), LPV/r or favipiravir is associated with a decrease in viral load compared with placebo. The hypothesis is that this holds for COVID-19 and that early antiviral treatment may prevent progression to the later phase of the disease.


FLARE is a phase IIA randomised, double-blind, 2x2 factorial placebo-controlled, interventional trial in which 240 participants, aged 18 years ( 18 years) to 70 years old inclusive will be recruited. Participants will be adults who have developed the early symptoms of COVID-19 within the first 5 days, or tested positive for SARS-CoV-2 within the first 7 days of symptom onset, or not presenting symptoms but tested positive within the last 48 hours (date/time of test must be within 48 hours of enrolment).

Eligible participants will be randomised 1:1:1:1 to receive one of the following


Favipiravir + Lopinavir/ritonavir (LPV/r) (both active); Favipiravir active + Lopinavir/ritonavir (LPV/r) placebo; Favipiravir placebo + Lopinavir/ritonavir (LPV/r) active; Favipiravir placebo + Lopinavir/ritonavir (LPV/r) placebo;

All participants will be enrolled and followed up for 28 days. A saliva sample for virological analysis and safety blood samples will be collected at baseline, as well as a diagnostic nose and throat swab, if the participant hasn't been tested for COVID-19 yet. Following randomisation, participants will take trial medication for 7 days and during this period will take a daily saliva sample and complete a symptoms diary including four daily temperature measurements.

Participants will have two follow-up visits at Day 7 and Day 14 where they will be assessed and undergo blood tests for toxicity and pharmacokinetic assessment (on Day 7 only) and provide stool samples. Participants will have a telephone follow up three (3) weeks after their last day of treatment (Day 7) and further information will be collected through a questionnaire.

Condition *COVID-19, Covid-19
Treatment Favipiravir, Favipiravir Placebo, Lopinavir/ Ritonavir, Lopinavir/ Ritonavir Placebo
Clinical Study IdentifierNCT04499677
SponsorUniversity College, London
Last Modified on8 May 2021


Yes No Not Sure

Inclusion Criteria

Any adult with the following
Symptoms compatible with COVID-19 disease (Fever >37.8oC on at least one occasion AND either cough and/ or anosmia) within the first 5 days of symptom onset
OR ANY symptoms compatible with COVID-19 disease (may include, but are not limited to fever, cough, shortness of breath, malaise, myalgia, headache, coryza) and tested positive for SARS-CoV-2 within the first 7 days of symptom onset
OR no symptoms but tested positive for SARS-CoV-2 within the last 48 hours (date/time of test must be within 48 hours of enrolment)
Male or female aged 18 years to 70 years old inclusive at screening
Willing and able to take daily saliva samples
Able to provide full informed consent and willing to comply with trial-related procedures

Exclusion Criteria

Known hypersensitivity to any of the active ingredients or excipients in favipiravir and matched placebo, and in lopinavir/ritonavir and matched placebo
Chronic liver disease at screening (known cirrhosis of any aetiology, chronic hepatitis (e.g. autoimmune, viral, steatohepatitis), cholangitis or any known elevation of liver aminotransferases with AST or ALT > 3 X ULN)
Chronic kidney disease (stage 3 or beyond) at screening: eGFR < 60 ml/min/1.73m2
HIV infection, if untreated, detectable viral load or on protease inhibitor therapy
Any clinical condition which the investigator considers would make the participant unsuitable for the trial
Concomitant medications known to interact with favipiravir and matched placebo, and with lopinavir/ritonavir and matched placebo, and carry risk of toxicity for the participant
Current severe illness requiring hospitalisation
Pregnancy and/ or breastfeeding
Eligible female participants of childbearing potential and male participants with a partner of childbearing potential not willing to use highly effective contraceptive measures during the trial and within the time point specified following last trial treatment dose
Participants enrolled in any other interventional drug or vaccine trial (co-enrolment in observational studies is acceptable)
Considering the importance of early treatment of COVID-19 to impact viral load, the absence of chronic liver/ kidney disease will be confirmed verbally by the participant during pre-screening and Screening/Baseline visit. Safety blood samples will be collected at Screening/Baseline visit (Day 1) and test results will be examined as soon as they become available within 24 hours
Participants who have received the COVID-19 vaccine
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