RedHill Biopharma is set to commence the Phase II/III clinical trial of its new drug candidate, RHB-107 (upamostat) to treat non-hospitalised patients with symptomatic Covid-19 in South Africa.

The move comes after the South African Health Products Regulatory Authority (SAHPRA) granted approval to conduct the trial in the country.

The trial is currently progressing in the US, with the expansion of trial centres underway to speed up subject enrolment.

Administered as a once-daily oral pill, RHB-107 acts on human serine proteases associated with preparing the spike protein for entry of the virus into target cells.

As the antiviral drug candidate is host-cell targeted, it is anticipated to be potentially effective against emerging viral variants of SARS-CoV-2 with spike protein mutations.

The two-part, multicentre, randomised, double-blind, placebo-controlled, parallel-group trial will assess the safety and efficacy of RHB-107 in symptomatic Covid-19 patients at the early stage of the disease in the out-patient setting.

The study will aid in selecting the apt dose and assess the time to a sustained recovery from illness as the primary goal.

RedHill Biopharma medical director Terry Plasse said: “South Africa, along with the US and rest of the world, urgently need the ability to easily and effectively treat Covid-19 and its variants, both inside and outside the hospital setting.

“The approval of this study in South Africa, along with the expansion of study sites in the US, are aimed at accelerating our efforts to bring RedHill’s two novel, oral compounds that cover the spectrum of Covid-19 disease severity, RHB-107 and opaganib, to patients across the world.”

In an in vitro human bronchial epithelial cell model, RHB-107 showed to robustly hinder SARS-CoV-2 viral replication.

Furthermore, the drug candidate possesses a favourable clinical safety and biodistribution profile, as shown in prior clinical trials, including several Phase I and Phase II trials for various indications, in nearly 200 subjects.

Separately, another oral drug of the company, opaganib, is being assessed in an international Phase II/III study in 475 severe Covid-19 patients in a hospital setting, with top-line data anticipated soon.

In June this year, RedHill concluded enrolment in the Phase II/III study of opaganib (Yeliva, ABC294640) in hospitalised patients with severe Covid-19 pneumonia.