The World’s Largest Meta-Analysis Using Real-World Favipiravir Data Demonstrates Significant Clinical Improvements and Promote Enhanced Viral Clearance in Mild-to-Moderate COVID-19 Patients

A series of recently published large-scale and independent meta-analyses have confirmed Favipiravir to be effective against mild to moderate COVID-19

DE – April 28th, 2022 – Cellvera, a US biopharmaceutical company, today reports a summary of recent studies demonstrating the efficacy of Favipriavir against several SARS-CoV-2 variants, including Delta and Omicron, and findings from the world’s largest meta-analysis. Cellvera, a company focused on discovering, developing, and commercializing antiviral therapies across a broad spectrum of infectious diseases, holds directly, or through its affiliates worldwide exclusive worldwide rights to Avigan 200mg (Favirpiravir) and higher strength formulations of the drug branded Qifenda 400MG and 800MG, a broad-spectrum oral antiviral treatment that targets COVID-19 and at least 12 other infectious diseases. Cellvera has developed and introduced the drug in several global markets since the start of the pandemic.

  • The world’s largest meta-analysis conclusively revealed that Favipiravir significantly improved viral clearance rates in mild to moderate patients versus control groups 14 days after onset of symptoms (relative risk [RR] = 1.16; 95% confidence interval [CI]: 1.04, 1.30; P = 0.008) [1]
  • The same study also examined clinical improvements in mild-to-moderate patient studies and found that Favipiravir was “significantly superior” to control groups in reducing the length of hospital stay (MD: −1.52; 95% CI: −2.82−0.23; P = 0.02)1
  • These results are consistent with an earlier independent systematic review and meta-analysis of favipiravir.2 Mild to moderate patients receiving Favipiravir exhibited significantly improved viral clearance on day 7 after treatment (odds ratio [OR] = 2.49; 95% CI = 1.19-5.22; P = 0.02)2
  • Favipiravir was also associated with superior clinical improvement to comparative therapy after seven days (OR = 1.60, 95% CI = 1.03–2.40, p = 0.04) and 14 days (OR = 3.03. 95% CI = 1.17–7.80, p = 0.02)
  • The efficacy against COVID-19, the above studies confirmed the safety of Favipiravir in line with the other studies and real-world observations

Favipiravir is a selective inhibitor of viral RNA-dependent RNA polymerase (RdRP) with potent antiviral activity against single-stranded RNA viruses, including coronaviruses. It targets the protein needed for the coronavirus to replicate, making it impossible for the virus to copy itself. The broad-spectrum antiviral drug is effective against 12 families of viruses, including Coronaviruses (COVID, MERS, SARS), Filoviruses (EBOLA, MARBURG), Flaviviruses (ZIKA, WEST NILE, DENGUE), RABIES, NOROVIRUS, and many others.

As novel strains of the SARS-CoV-2 virus continue to emerge, preliminary studies on SARS-COV-2 variants—Omicron and Delta—have shown that Favipiravir maintains its antiviral activity, demonstrating the inability of viruses to form resistance to Favipiravir even with prolonged exposure of virus-infected cells to the drug.[2]3 Favipiravir remains an invaluable asset for emergency preparedness strategies against this constantly evolving COVID-19 virus and other potential future pandemics. 

On the international stage, the Thailand Disease Control Department (DDC) recently announced its official position on Favipiravir, stating that “the drug was effective in treating mild and moderate symptoms and numerous patients are given Favipiravir recovered and were discharged from hospitals.4 In patients administered Favipiravir, the clinical improvement rate was 79% after 14-days of monitoring, compared to a 32.2% improvement rate in the control group.

Cellvera recently announced their support of the UK government and the University of Oxford in their national priority platform trials of COVID-19 treatments. Platform Randomised Trial of Treatments in the Community for Epidemic and Pandemic Illnesses (PRINCIPLE) is one of the world’s most extensive trials currently in a community setting, seeking treatments for outpatient use. In April 2021, the University of Oxford announced that Favipiravir would be investigated in the UK; a trial was set up with the intention that drugs shown to have a clinical benefit could be rapidly introduced into routine National Health Service (NHS) care. However, except for Favipiravir, the other three drugs selected for this trial were discontinued due to futility within weeks, with a continued expansion of the number of patients being administered Favipiravir.

Since 2014, Favirpiravir has been extensively studied and evaluated in 40 clinical trials before the COVID-19 pandemic. In some prior trials, like PRESECO in the US, Favipiravir did not demonstrate efficacy due to insufficient dosage available to patients or late treatment. At the same time, the mounting evidence from the world’s large meta-analysis points to a proven efficacy of Favipiravir against SARS-COV-2 and its variances. However, Favipiravir continues to demonstrate significant clinical improvements and promotes enhanced viral clearance in mild-to-moderate COVID-19 patients as the data from several clinical trials showed that:

  • No viral resistance to Favipiravir, even with prolonged exposure of virus-infected cells to the drug.
  • Favipiravir maintains its antiviral activity against SARS-COV-2 variants—Omicron and Delta⁴.
  • Favipiravir was significantly superior to control groups in reducing the length of hospital stay; it also improved viral clearance rates in mild to moderate patients versus control groups 14 days after onset of symptoms.
  • More than 70% of mild to moderate patients experienced relief of symptoms on day 3, clinical improvement, and remission on day 7, and more than 90% achieved full recovery by day 14.
  • COVID-19 patients with hypertension and diabetes experienced a significant decrease in fever reduction and cough relief when treated with favipiravir compared to the standard of care.

About Cellvera

Cellvera is a biopharmaceutical company focused on discovering, developing, and commercializing oral therapies and monitoring tools to address the unmet medical needs of patients with life-threatening viral diseases. Cellvera is focused on the clinical and commercial development of orally available, potent, and selective nucleotide prodrugs for difficult-to-treat, life-threatening viral infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, dengue virus, hepatitis C virus (HCV) and respiratory syncytial virus (RSV).

Driven to Discover. Cellvera’s team includes PhDs in computational biology, biochemistry, chemistry, and senior software engineers.

For more information:


1. Deng, W., Yang, C., Yang, S., Chen, H., Qiu, Z., & Chen, J. (2022). Expert review of anti-infective therapy, 20(4), 555–565.

2. Manabe, Toshie; Kambayashi, Dan; Akatsu, Hiroyasu; Kudo, Koichiro. BMC Infect Dis ; 21(1): 489, 2021 May 27.

3. Anti-coronavirus Avifavir drug is effective against delta, omicron strains — developer. CORONAVIRUS PANDEMIC 28 DEC 2021. Data retrieved 17 APRIL 2022.

4. Anti-coronavirus Avifavir drug is effective against delta, omicron strains — developer. CORONAVIRUS PANDEMIC 28 DEC 2021.

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