Real-World Effectiveness and Optimal Dosage of Favipiravir for Treatment of COVID-19: Results from a Multicenter Observational Study in Thailand

Abstract

Favipiravir is a broad-spectrum oral antiviral agent that shows in vitro activity against SARS-CoV-2. Presently, data on the real-world effectiveness and optimal dosage of favipiravir for treating COVID-19 are limited. We conducted a retrospective observational study of hospitalized adult patients with COVID-19 at five tertiary care hospitals in Thailand. We reviewed patient charts to obtain all necessary data. Among 247 COVID-19 patients, 63 (23.0%) received ≥1 dose of favipiravir. Of these 63 patients, 61.9% were male with a median age of 48 years (range 22–85 years), 27.0% required an O2 nasal cannula, 9.5% required non-invasive ventilation and/or high-flow O2 therapy, and 6.4% required invasive mechanical ventilation and/or ECMO. The median baseline NEWS2 score was 5 (0–16). The Day-7 clinical improvement rate [95%CI] was 66.7% [53.7–78.0%] in all patients, 92.5% [75.7–99.1%] in patients who did not require O2 supplementation, and 47.2% [0.4–64.5%] in patients who required O2 supplementation. No life-threatening adverse events were identified. The 28-day mortality rate was 4.8%. A multivariate analysis revealed three poor prognostic factors for Day-7 clinical improvement (odds ratio (95%CI); p-value): older age (0.94 (0.89–0.99); p = 0.04), a higher baseline NEWS2 score (0.64 (0.47–0.88); p = 0.006), and a lower favipiravir loading dose (≤45 mg/kg/day) (0.04 (0.005–0.4); p = 0.006). In conclusion, our study reports the promising effectiveness of favipiravir for treating COVID-19 patients. In addition to older age and a high baseline NEWS2 score, a low loading dose of favipiravir (≤45 mg/kg/day) was also identified as a poor prognostic factor for early clinical improvement. Further studies to explore the optimal dose and the optimal timing of drug initiation for favipiravir should be performed.

Favipiravir—Tautomeric and Complexation Properties in Solution

“…This has posed a need for vital scientific breakthroughs, which include innovative approaches to developing vaccines and antiviral drugs. The Japanese anti-influenza drug favipiravir [ 13 , 14 , 15 , 16 , 17 , 18 ] has shown promising results in the treatment of the disease in China, India, Russia and other countries [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ], either alone [ 26 , 27 , 28 , 29 , 30 ] or in combination [ 31 , 32 , 33 , 34 , 35 , 36 ] with other antiviral compounds.…”

Remdesivir versus Favipiravir in Hospitalized Patients with Moderate to Severe COVID-19 Pneumonia: A Propensity Score-Matched Retrospective Cohort Study

“…In a retrospective observational study, patients treated with favipiravir exhibited a Day-7 clinical improvement rate of 66% and a 4.8% 28-day mortality rate. 16 Real-world data analysis in Thailand demonstrated that favipiravir monotherapy outperformed supportive treatment, shortening recovery time in early symptomatic COVID-19 patients and reducing the 28-day mortality risk in severe COVID-19. 17 Whereas, in mild to moderate COVID-19, there was no difference in the time to sustained clinical recovery between patients who received favipiravir compared with placebo.…”

Mexican Delphi Consensus to Use Favipiravir in Patients with COVID 19 (Expert Panel)

“…The objective of this panel is to generate a consensus on the use of Favipiravir in Mexican patients with COVID 19 infection, identifying needs and opportunities in the universe of patients who to date do not have established guidelines or standard treatment present in the country. Identifying the group of patients who can benefit from antiviral treatment in the early stage and reduce the morbidity and mortality presented in the pandemic [13][14][15][16][17].…”