Favipiravir is intended to be provided for free in 20 countries inclusive of Indonesia, Iran, Saudi Arabia and Turkey, for treatment of COVID-2019 infections. In April 2020, FUJIFILM Corporation reported that it allocated additional capacity at its FUJIFILM Wako Pure Chemical Co Ltd facility in Japan, for production of pharmaceutical intermediates used to manufacture favipiravir. This is expected to provide quicker access to the drug, for treatment of COVID-2019 infections. Fujifilm also established strategic partnerships with domestic and overseas companies for diverse manufacturing processes to source raw materials and pharmaceutical substances   .
In May 2020, FUJIFILM Toyama Chemical initiated a phase III trial of favipiravir verses hydroxycholorquine and azithromycin and zinc verses standard care in patients hospitalised with COVID-19 infections (NCT04373733; EudraCT2020-001449-38; CW002). The open-label randomised trial intends to enrol 450 patients in the UK  .
In May 2020, Health Canada approved the clinical trial application (CTA) of Appili Therapeutics for initiating the prophylactic phase II trial of favipiravir as a preventive measure against COVID-2019 infections  . Earlier, in the same month, Appili Therapeutics had filed the CTA with Health Canada to initiate the prophylactic phase II trial to evaluate favipiravir as a preventive measure against COVID-2019 infections in Canada. The primary endpoint of the trial is safety and efficacy of favipiravir in the prevention of COVID-2019 infections  .
In April 2020, FUJIFILM Corporation initiated a phase II proof-of-concept trial to evaluate the safety and efficacy of favipiravir with standard of care (SoC) or SoC alone in patients with COVID-2019 infections (NCT04358549; FAVI-COV-US201). The primary endpoint of the trial is to determine the time to viral clearance in 29 days. The open-label, randomizsd, controlled trial intends to enrol approximately 50 pateints in the US   .
As at April 2020, clinical development for treatment of COVID-2019 infections was underway in Middle East  .
Results from clinical studies in COVID-2019 infections in China released in April 2020 were generally positive, with mild side effects experienced in some patients. Earlier, in March 2020, the drug was approved for clinical development in COVID-2019 infections, in China  .
In March 2020, FUJIFILM Toyama Chemical initiated a phase III trial in Japan, to assess the safety and efficacy of favipiravir, for patients afflicted with COVID-2019 infections   .
As of March 2020, Zhejiang Hisun Pharmaceutical conducted a clinical trial in collaboration with Third People's Hospital of Shenzhen in 80 patients with COVID-2019 infections and results were released   .
As of March 2020, Zhejiang Hisun Pharmaceutical conducted a clinical trial in collaboration with Zhongnan Hospital in 120 patients with COVID-2019 infections and results were released   .
Influenza virus infection (oral formulation)
in March 2014, Toyama Chemical announced that favipiravir (Avigan® tablet 200mg) had been approved in Japan for the treatment of influenza virus infections. The product has subsequently been launched  .
In July 2015, FUJIFILM Holdings Corporation revealed that the Taiwanese Centres for Disease Control (CDC) has decided to import and stockpile favipiravir, prior to grating approval for the manufacturing and marketing of the drug in Taiwan. The Taiwanese CDC has commissioned Standard Chemical & Pharmaceutical Company to import favipiravir  .
Toyama Chemical initiated phase III development of favipiravir in Japan in October 2009. The trail in Japan was an international joint trial that involved samples in Taiwan   . The company, in June 2010, completed a phase II study that evaluated the safety and efficacy of two doses of favipiravir, in subjects with influenza virus infection (JapicCTI080505). The study was initiated in January 2008 in Japan  .
In February 2015, MDVI, in collaboration with MediVector, completed a phase III trial that evaluated the safety and efficacy of favipiravir in adult patients with uncomplicated influenza (FAVOR Flu; T705US317; U1111-1147-8470; NCT02008344). The randomised, double-blind, placebo-controlled trial was initiated in December 2013. The United States Department of Defense's BioDefense Therapeutics reported that the first patient had been enrolled in the US in January 2014  . Enrolment of a total of 1161 patients was completed in February 2015 in the US, Argentina, Brazil, Canada, Colombia, Dominican Republic, El Salvador, Guatemala, Mexico, Peru and Puerto Rico    .
In March 2015, FUJIFILM Pharmaceuticals completed a phase III trial that assessed the safety and efficacy of favipiravir in adult patients with uncomplicated influenza (FAVOR; T705US316; EudraCT 2013-002149-13; NCT02026349). The randomised, double-blind, placebo-controlled trial was initiated in January 2014 and enrolled 860 patients in the US, Australia, Belgium, Bulgaria, Hungary, the Netherlands, New Zealand, Poland, Russia, South Africa, Spain, Sweden, Turkey and Ukraine   .
A multi-national, randomised, double-blind, placebo-controlled phase II trial of favipiravir was completed in May 2012 (T705aUS204; NCT01068912). The trial, which was initiated in February 2010 by Toyama Chemical, assessed the safety and efficacy of two dosing regimens of favipiravir in patients aged 55 to 80 years who had uncomplicated influenza. A total of 530 patients were recruited in the US, Chile, Paraguay, Peru, South Africa, Australia and New Zealand. Favipiravir demonstrated a significantly rapid clearance of virus, compared with placebo; the compound was also well tolerated and no adverse events were reported    . However, as of August 2015, no recent reports of development for favipiravir have been identified in Chile and Paraguay.
Results of a phase II trial showed that twice daily dosing of favipiravir demonstrated statistically significant decreases in time to alleviation of influenza symptoms. Based on these positive top-line results, MediVector plans to initiate phase III studies in November 2013  .
In February 2013, FUJIFILM Pharmaceuticals completed the phase I/II trial that evaluated the safety and pharmacokinetics of different regimens of favipiravir in healthy volunteers and in patients with uncomplicated influenza (NCT01728753). The randomised, double-blind, placebo-controlled trial enrolled 550 participants in the US  .
Favipiravir has undergone phase I development in the US for the treatment of influenza   . In March 2013, FUJIFILM Pharmaceuticals USA completed a phase I trial to determine the pharmacokinetics of favipiravir (T705aUS109; NCT01419457). The open-label, parallel-assignment, multiple dose trial enrolled 36 healthy volunteers and patients with hepatic impairment, in the US by invitation. Toyama Chemical initiated the trial in August 2011  .
Preclinical studies in mice have demonstrated the efficacy of oral favipiravir  .
Influenza virus infection (injection formulation)
FUJIFILM, Zhejiang Hisun Pharmaceutical, the China-Japan Friendship Clinic and the National Engineering Research Center for the Emergency Drug signed a memorandum in October 2018 and are planning to develop injection formulation of favipiravir for serious influenza infections in China  .
Ebola virus infection
In April 2016, Institut National de la Santé Et de la Recherche Médicale initiated the phase II FORCE trial to assess the safety, tolerance and efficacy of favipiravir high dose in male survivour of Ebola virus disease (EVD) with Ebola virus (EBOV) RNA, in semen (C15-101; NCT02739477). The dose-escalation, open-label, single-group trial will enrol approximately 18 patients in Guinea  .
In December 2014, the French Institut National de la Santé Et de la Recherche Médicale (INSERM) initiated the phase I JIKI trial to assess the efficacy of favipiravir in patients with Ebola virus disease (C14-63; NCT02329054). Mortality assessed at day 14 is the defined primary endpoint of the trial. The open-label trial is expected to enrol approximately 225 patients in Guinea  . INSERM conducted the trial with funding from the EU. Interim efficacy and safety results were released by FUJIFILM in March 2015  .
MediVector, under a contract with Medical Countermeasure Systems and BioDefense Therapeutics of United States Department of Defense, plans to submit an IND application to the FDA for supporting clinical trials in Africa. The trials are designed to evaluate the safety and antiviral activity of favipiravir against Ebola virus infections  .
In October 2014, FUJIFILM announced that the National Agency for Medicines and Health Products Safety (ANSM) has reported that favipiravir in combination with another unapproved drug was successfully used to treat an Ebola infected patient in France. The company also reported that it has supplied the drug to the University Hospital Frankfurt for the treatment of another patient in Germany. FUJIFILM also stated that the Government of France and Guinea are planning a medium scale clinical trial to evaluate the efficacy of favipiravir for the treatment of Ebola virus infections; and the company intends to supply the drug for these trials   . Later in the same month, FUJIFILM announced that the company intended to initiate production of the drug, for supply in clinical trials  .
BioDefense Therapeutics reported in January 2014 that it is testing the efficacy of favipiravir against the Ebola virus, as well as other viruses considered threats to service members  .
In February 2018, Toyama Chemical initiated a phase III trial to evaluate the efficacy and safety of favipiravir against ixodid tick-borne infectious disease, severe fever with thrombocytopenia syndrome (SFTS) (JapicCTI183872). The open label trial intends to enrol patients in Japan   .
In preclinical models, favipiravir was demonstrated to be efficacious against severe fever with thrombocytopenia syndrome  .
Favipiravir label in Japan mentions that the drug should be contraindicated for women who are pregnant or may possibly be pregnant, and in women of childbearing potential and men whose partner is of childbearing potential should be advised to use contraception. The label also indicates to have a precautionary statement about the early-embryo toxicity and teratogenicity of favipiravir to be provided in the WARNING section of the package insert  .