AIM ImmnunoTech has released topline results from a Phase II trial evaluating its Ampligen (rintatolimod) drug in people with post-Covid fatigue.

Results showed that the drug failed to meet its primary endpoint of significant change from baseline at 13 weeks in the PROMIS fatigue score.

The US-based company said that although Ampligen did not meet the primary endpoint, the “initial analysis revealed that subjects in the Ampligen group had experienced lower levels of fatigue at multiple time points during the treatment phase when compared to the placebo group”.

The two-arm, placebo-controlled Phase II AMP-518 trial (NCT05592418) enrolled 80 patients with post-Covid fatigue. Secondary and ad hoc endpoint analysis found that the difference in change from baseline in the PROMIS fatigue score between Ampligen and placebo groups was reached or approached statistical significance at several time points during the treatment phase.

Another secondary endpoint, a six-minute walk test, revealed a higher impact of Ampligen on distance travelled in six minutes at week 13 compared to the placebo. AIM’s CEO Thomas E Equels stated that the “Ampligen group outperformed the placebo group in PROMIS measures of fatigue in 12 of the 13 weeks tracked.” Adding that the company plans to use the six-minute walk test results to inform future trial design.

Out of the 80 patients enrolled in the trial, 66 patients completed the study. The primary reasons for discontinuation from treatment included withdrawal by the subject, lost to follow-up, and adverse events.

Six participants in the Ampligen group observed mild treatment-emergent adverse events (TEAEs). Two subjects either discontinued or interrupted treatment in the Ampligen group due to TEAEs. Ten and four participants observed TEAEs in the treatment and placebo groups, respectively.

Ampligen is a mismatched, double-stranded RNA molecule with immunomodulatory and antiviral properties. In 2018, the US Food and Drug Administration (FDA) approved the compassionate care (expanded access) programme to allow for the treatment of up to 100 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients at any one time at approved clinical infusion therapy sites.

Ampligen is also being investigated in a Phase Ib/II trial as a combination therapy with AstraZeneca’s Imfinzi (durvalumab) for the treatment of metastatic pancreatic ductal adenocarcinoma. The trial is taking place in the Netherlands and is part of an externally sponsored collaborative clinical research agreement between AIM, AstraZeneca, and Erasmus Medical Centre.