ARCA biopharma said that its investigational new drug (IND) application for AB201 (rNAPc2) as a potential treatment for patients hospitalised with Covid-19 has been approved by the US Food and Drug Administration (FDA).

With the IND approval in place, the company expects to launch a phase 2b/3 sequential clinical trial of AB201 in the fourth quarter of 2020.

The phase 2b part of the ASPEN-COVID-19 trial will feature nearly 100 patients hospitalised after contracting the novel coronavirus.

ARCA biopharma said that some of the patients have a complicated clinical course because of a virus-triggered coagulopathy. These include thrombotic events and inflammatory processes, which are believed to be mediated partly by tissue factor production, said the company.

According to the company, AB201 is a potent selective inhibitor of tissue factor (TF) that also has anti-inflammatory and antiviral properties.

ARCA biopharma said that a contiguous phase 3 trial of the small recombinant protein will be taken up based on the results of the phase 2 results.

The company expects to release data from the ASPEN-COVID-19 trial in the second quarter of next year.

According to ARCA biopharma, the phase 2b trial is likely to be a randomised study that will compare two dose regimens of AB201 with heparin prescribed per local standard of care.

The phase 2b trial’s primary endpoint will be variation in D-dimer level from baseline to the eighth day of treatment.

D-dimer is a commonly used biomarker for evaluating activation of coagulation, which is at elevated levels in nearly half of the hospitalised Covid-19 patients and is directly related to adverse clinical outcomes, said the company.

If a favourable effect on D-dimer levels is shown by the trial, after the FDA review of the data and identification of the proposed phase 3 AB201 dose, the company will begin enrolling patients for the phase 3 trial.

ARCA biopharma president and CEO Michael Bristow said: “The ASPEN-COVID-19 trial will use the coagulopathy biomarker D-dimer to identify an optimal dose from AB201 regimens that are both within the therapeutic range as determined from Phase 2 trials investigating cardiovascular thrombosis prophylaxis.

“If successful, we anticipate using this dose in a planned Phase 3 trial to evaluate potential improvement in clinical outcomes. We believe that the combination of anticoagulant, anti-inflammatory and antiviral effects of AB201 may favourably impact clinical recovery of patients hospitalised with Covid-19.”

The phase 3 trial of AB201 is expected to have 450 patients with its primary endpoint being clinical recovery as measured by the Adaptive COVID-19 Treatment Trial (ACTT-1) ordinal scale. Secondary endpoints of the phase 3 trial are D-dimer levels and the number of thrombotic events, among others.