Innate Pharma has decided to suspend the development of its drug candidate, avdoralimab, for treating Covid-19 after its Phase II FORCE clinical trial failed to meet the primary endpoints.

The investigator-sponsored, multi-centre, randomised, double-blind, placebo-controlled trial assessed the safety and efficacy of the drug in 208 Covid-19 patients with severe pneumonia.

An antibody, avdoralimab selectively attaches and inhibits C5a receptors (C5aR1) found on subsets of myeloid-derived suppressor cells (MDSC) and neutrophils.

The company initiated the FORCE trial based on data from a preclinical study, which found that patients progressing to severe Covid-19 display C5a/C5aR1 pathway activation.

These translational findings were demonstrated in the trial but did not translate into clinical benefit compared with best supportive care, Innate Pharma said.

The trial did not meet its primary endpoint of clinical improvement on the WHO scale at days 14 and 28 in all three cohorts.

Patients with severe pneumonia and no acute respiratory disease syndrome (ARDS) at baseline were part of the first cohort while the second cohort included those with ARDS and admitted to the ICU.

Participants in the third cohort had Covid-19-associated ARDS and needed mechanical ventilation.

Data also revealed slightly more deaths with avdoralimab versus placebo and causality was not determined.

Innate Pharma plans to submit the FORCE trial results, including translational data, for publication. It decided to suspend testing of avdoralimab for Covid-19 based on these data.

Innate Pharma chief medical officer Joyson Karakunnel said: “The FORCE trial was an opportunistic endeavour to help patients with severe Covid-19, and was supported by pre-clinical data showing the importance of the C5aR1 pathway in the escalation of disease.

“While we are disappointed with the results, these data contribute to the scientific understanding of the inflammatory pathways in this disease and potential avenues for treatment.”

These latest data do not affect the ongoing investigator-sponsored Phase II trial of avdoralimab to treat bullous pemphigoid, an inflammatory disease.

Approximately 100 patients received the drug in inflammation and cancer trials without any new or unexpected safety signals reported.