RedHill Biopharma announced promising preliminary results from a preclinical study within which opaganib, a novel, orally administered sphingosine kinase 2 (SK2) selective inhibitor, (administered at 250mg/kg,) demonstrating a reduction of thrombosis (blood clotting) in an acute respiratory distress syndrome (ARDS) – a preclinical animal model designed to measure thrombotic (blood clot) risks.

This latest finding points towards another potential benefit of opaganib to COVID-19 patients – in addition to the already established inhibition of SARS-CoV-2 replication and the potential reduction in hyper immune-response by opaganib. Following these preliminary findings, additional work is being planned to evaluate the range of potential physiologically and pharmacologically relevant opaganib doses with respect to thrombosis reduction.

"Acute Respiratory Distress Syndrome (ARDS) is one of the most dangerous outcomes of COVID-19 disease, putting severely ill COVID-19 patients at an increased risk of potentially fatal venous thrombosis and pulmonary embolism.  There are currently very limited options available to physicians that have been shown to be effective against ARDS, and specifically against ARDS-induced thrombosis," said Reza Fathi, PhD., RedHill's Senior VP, R&D. "Results from our study show opaganib 250 mg/kg reduced blood clot length, weight and total thrombus score in a preclinical model of ARDS. This adds to the known antiviral and anti-inflammatory activities of opaganib and provides the potential for a unique triple-action effect on the pathophysiological processes associated with COVID-19 disease. Opaganib, which targets a host cell component, potentially minimizes the likelihood for resistance due to viral mutations. Before the end of this month, we expect topline clinical data insights into the safety and potential efficacy signals of opaganib from the non-powered U.S. Phase 2 study in which the last patient has been given their last dose on November 26, followed in Q1/2021 by top-line data from the larger global Phase 2/3 study, which is powered for efficacy and already more than 60% enrolled."

"The ARDS thrombosis model we used to conduct this work is validated and highly predictive, and the results we saw with opaganib are impressive and provide reason for promise," said Sebastien Labbe, Ph.D., Director, Translational Research at IPS Therapeutique Inc., who carried out the study. "The results provide insight into a highly desirable potential effect of opaganib for use in managing patients with severe COVID-19, whose prognosis can be very poor." 

ARDS-induced thrombosis may occur in up to one-third of COVID-19 patients requiring Intensive Care Unit (ICU) admission and up to 9% of all hospitalized patients and is associated with a poor prognosis. The preclinical study was designed to assess the efficacy of opaganib in reducing the incidence of adverse thromboembolic events in situ in the lipopolysaccharide (LPS)-induced model of pulmonary inflammation, a reliable model of ARDS that can mimic COVID-19 inflammation.

The results from the preclinical study of opaganib are preliminary and were provided to the Company by an independent third-party following an initial independent analysis and remain subject to additional review and analysis. Such review and analysis may result in findings inconsistent with the results disclosed in this release and may not be replicated in future preclinical or clinical studies.

Opaganib is a novel, orally administered, sphingosine kinase-2 (SK2) selective inhibitor with demonstrated dual anti-inflammatory and antiviral activity that acts on both the cause and the effects of COVID-19 disease, targeting a host cell component involved in viral replication, potentially minimizing likelihood of resistance due to viral mutations.

A U.S. Phase 2 study with opaganib in patients with severe COVID-19 pneumonia (NCT04414618) has completed enrollment of all 40 subjects, and the last patient has been given their last dose – top-line data is expected later this month. This Phase 2 study is not powered for efficacy and is focused on safety evaluation and identification of efficacy signals.

In parallel, enrollment in the 270-patient global Phase 2/3 study with opaganib in patients with severe COVID-19 pneumonia (NCT04467840) is over 60% complete. The study is approved in six countries and is on track to deliver topline data in the first quarter of 2021. This study is focused on and powered for efficacy evaluation, and recently received a unanimous recommendation to continue by an independent Data and Safety Monitoring Board (DSMB), following a pre-scheduled safety review of the first 70 patients to have been treated for 14 days. The DSMB is scheduled to conduct a second pre-planned safety review this month of the first 135 patients who have reached the primary endpoint, and this will later be followed by a prescheduled, unblinded futility interim analysis of efficacy data from the same patients. The Company will remain blinded to this data.

Opaganib, a new chemical entity, is a proprietary, first-in-class, orally administered, sphingosine kinase-2 (SK2) selective inhibitor with a demonstrated unique triple-action effect on the pathophysiological processes associated with COVID-19 disease, that targets a host cell component, potentially minimizing the likelihood for resistance due to viral mutations. Opaganib has also shown anticancer activity and has the potential to target multiple oncology, viral, inflammatory and gastrointestinal indications.

Opaganib is being evaluated in a global Phase 2/3 study and a U.S. Phase 2 study for the treatment of severe COVID-19 pneumonia. Opaganib also received Orphan Drug designation from the U.S. FDA for the treatment of cholangiocarcinoma and is being evaluated in a Phase 2a study in advanced cholangiocarcinoma and in a Phase 2 study in prostate cancer.

Preclinical data have demonstrated both anti-inflammatory and antiviral activities of opaganib, with the potential to reduce inflammatory lung disorders, such as pneumonia, and mitigate pulmonary fibrotic damage. Opaganib demonstrated potent antiviral activity against SARS-CoV-2, the virus that causes COVID-19, completely inhibiting viral replication in an in vitro model of human lung bronchial tissue. Additionally, preclinical in vivo studies have demonstrated that opaganib decreased fatality rates from influenza virus infection and ameliorated Pseudomonas aeruginosa-induced lung injury by reducing the levels of IL-6 and TNF-alpha in bronchoalveolar lavage fluids.

Opaganib was originally developed by U.S.-based Apogee Biotechnology Corp. and completed multiple successful preclinical studies in oncology, inflammation, GI, and radioprotection models, as well as a Phase 1 clinical study in cancer patients with advanced solid tumors and an additional Phase 1 study in multiple myeloma.

Under a compassionate use program, patients with severe COVID-19 (as classified by the WHO ordinal scale) were treated with opaganib in a leading hospital in Israel. Data from the treatment of these first patients with severe COVID-19 with opaganib have been published. Analysis of treatment outcomes suggests substantial benefit to patients treated with opaganib under compassionate use in both clinical outcomes and inflammatory markers as compared to a retrospective matched case-control group from the same hospital. All patients in the opaganib-treated group were discharged from hospital on room air without requiring intubation and mechanical ventilation, whereas 33% of the matched case-control group required intubation and mechanical ventilation. Median time to weaning from high-flow nasal cannula was reduced to 10 days in the opaganib-treated group, as compared to 15 days in the matched case-control group.

The development of opaganib has been supported by grants and contracts from U.S. federal and state government agencies awarded to Apogee Biotechnology Corp., including from the NCI, BARDA, the U.S. Department of Defense and the FDA Office of Orphan Products Development.