Phase 2/3 study of oral RHB-107 in non-hospitalized COVID-19 patients shows promising results

RedHill Biopharma Ltd. (Nasdaq: RDHL) ("RedHill" or the "Company"), a specialty biopharmaceutical company, today announced positive top-line results from the Phase 2 part of the Phase 2/3 study of once-daily oral RHB-107 (upamostat) in non-hospitalized symptomatic COVID-19 patients, predominantly conducted in the U.S. (60/61 patients) as well as South Africa.

Although not powered for efficacy assessment, the study showed highly promising efficacy results delivering a 100% reduction in hospitalization due to COVID-19, with zero patients on RHB-107 hospitalized with COVID-19 (0/41) compared to 15% on the placebo-controlled arm requiring hospitalization (3/20) (nominal p-value=0.0317). Furthermore, the study showed an 87.8% reduction in reported new severe COVID-19 symptoms, with only one patient on RHB-107 (2.4%, 1/41) compared to 20% (4/20) of patients on the placebo-controlled arm experiencing new COVID-19 related severe symptoms (nominal p-value=0.036).

The study met its primary outcome measure, demonstrating a favorable safety and tolerability profile of RHB-107. Study arms were well balanced with respect to baseline disease severity, risk factors and vaccination status. Patients were also tested for the specific viral strain (last patient randomized November 12, 2021), with the most common variant being Delta, found in 62.5% of the patients that had next generation sequencing (NGS).

These very promising efficacy results, achieved despite a small overall sample size, are impressive. Coupling the efficacy results with successfully meeting the primary endpoint of good safety and tolerability and convenient once-daily dosing, positions oral RHB-107 as a potential highly beneficial treatment for COVID-19 outpatients early in the course of disease in order to reduce symptom severity and prevent disease progression and hospitalization. Given the limitations of current options for early treatment of COVID-19, we are excited to progress the development of RHB-107, subject to additional discussions with regulatory authorities. Equally important is our expectation that RHB-107, with its human cell factor targeting, would maintain its action irrespective of spike protein mutations, thus likely making it a highly desirable variant-agnostic potential treatment option."

Terry F. Plasse MD, Medical Director at RedHill

The Phase 2/3 multicenter, randomized, double-blind, placebo-controlled, parallel-group study (NCT04723527) with RHB-107 is aimed at evaluating treatment in patients with symptomatic COVID-19 early in the course of the disease, with a once-daily oral treatment that can be prescribed and used in the non-hospitalized patient population. The Phase 2 part of the study was designed to evaluate safety for dose selection and to provide preliminary assessment of parameters to be used for efficacy evaluation in Part B. A total of 61 patients were enrolled in Part A and randomized on a 1:1:1 basis to receive one of two dose levels of RHB-107 or a placebo control.

Next steps for the study will follow data submission and discussion with regulators.