Virios Therapeutics has reported topline data from its Phase IIb clinical trial of antiviral combination therapy, IMC-1, to treat fibromyalgia (FM).

Named FORTRESS, the placebo-controlled, double-blind trial assessed the safety and efficacy of oral IMC-1. 

It enrolled 425 female subjects aged 18 to 65 years with FM. These subjects were randomised into a 1:1 ratio to receive either IMC-1 or a matching placebo. 

Decline in pain as evaluated by the variation from baseline to week 14 in the diary Numerical Rating Scale (NRS) weekly average of average pain severity scores reported by the subject daily was the trial’s prespecified primary endpoint.

The trial also evaluated the potential of IMC-1 to boost fatigue and sleep disturbance symptoms and improvements in complete global health status and participant function.

According to the findings, the trial failed to meet statistical significance on the primary efficacy endpoint. 

No improvement was seen in subjects following treatment with IMC-1 versus placebo during the trial’s first half when the Delta variant was prevalent.

During the study’s second half, when the Omicron variant was dominant, subjects who received IMC-1 had a statistically significant improvement in the primary endpoint at week 14.

On the crucial secondary PROMIS Fatigue assessment and the Fibromyalgia Impact Questionnaire-Revised (FIQR) symptoms domain score, improvements were reported.

In the trial, IMC-1 was found to be well-tolerated.

A lead candidate of the company, IMC-1 is a fixed dose cocktail of famciclovir and celecoxib. 

The treatment could potentially suppress the replication of the herpes virus.

Virios Therapeutics chairman and CEO Greg Duncan said: “We were surprised by the overall primary efficacy result from this study, as we believe this approach continues to have scientific validity and the potential to provide FM patients with a much-needed, well-tolerated therapeutic option. 

“We believe the interplay between different Covid-19 strains and herpes virus activation may be contributing to the differential response we observed in patients enrolled in 2021 versus 2022.” 

In August this year, the company dosed the first participant in the exploratory long Covid trial of IMC-2.