Fujifilm Toyama Chemical has announced plans to terminate subject enrolment in the Phase III clinical trial of Avigan tablet (favipiravir) for treating Covid-19 patients in Japan. 

Enrolment of early-onset Covid-19 patients with disease progression risk is currently underway in the trial. Fujifilm intends to halt subject enrolment by the end of this month.

The company attributed the termination of new subject enrolment to the spread of the Omicron variant of the SARS-CoV-2 virus. 

The company noted that even if trials progressed according to the existing trial protocol, it would be hard to establish the efficacy of Avigan in preventing symptoms from becoming severe and continuing the placebo control trial would not benefit trial participants.

The double-blind, placebo-controlled trial is analysing the efficacy of Avigan to avert progression to severe disease in individuals infected with Covid-19. 

The ratio of subjects whose symptoms became severe will be the primary endpoint of the trial.

Compared to other viral strains, Omicron has reduced rates of symptom severity and most of the patients being enrolled in the trial were infected by this strain.

In accordance with the trial protocol, the clinical data of the subjects enrolled in the trial will be evaluated in the future. 

To date, serious adverse events that are directly linked to the investigational drug were not observed in the trial.

In April last year, Fujifilm started the Phase III trial of Avigan tablet in Japan for the treatment of Covid-19 patients.

An anti-influenza drug, Avigan received domestic manufacturing and marketing approval in the country in 2014 for treating infection caused by new or re-emerging influenza viruses.