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RedHill and U.S. Army Announce Opaganib and RHB-107 Combinations with Remdesivir Show Distinct Synergistic Effect Against Ebola

https://finance.yahoo.com/news/redhill-u-army-announce-opaganib-134500031.html

Investigational drugs opaganib and RHB-107 (upamostat) demonstrate distinct synergistic effect when combined individually with remdesivir, significantly improving potency while maintaining cell viability, in a new U.S. Army-funded and conducted in vitro Ebola virus study

Opaganib and RHB-107 are both novel, oral, host-directed, small molecule investigational drugs that are easy to administer and distribute, with demonstrated activity against multiple viral targets, including COVID-19, and are expected to be effective against emerging viral variants

Opaganib is believed to be the first host-directed molecule to show activity in Ebola virus disease, having recently delivered a statistically significant increase in survival time in a separate U.S. Army-funded in vivo Ebola virus study. RHB-107 was recently accepted for inclusion in the ACESO PROTECT adaptive platform trial for early COVID-19 outpatient treatment

TEL-AVIV, Israel and RALEIGH, N.C., Dec. 20, 2023 /PRNewswire/ -- RedHill Biopharma Ltd. (Nasdaq: RDHL) ("RedHill" or the "Company"), a specialty biopharmaceutical company, today announced that its two novel, oral host-directed investigational drugs, opaganib[1] and RHB-107 (upamostat)[2], demonstrated robust synergistic effect when combined individually with remdesivir (Veklury®)[3], significantly improving viral inhibition while maintaining cell viability, in a new U.S. Army-funded and conducted Ebola virus in vitro study.

"These encouraging in vitro results for opaganib and RHB-107 show a distinct synergy in terms of viral inhibition while maintaining cell viability (i.e., not increasing toxicity), when either is added to remdesivir, with opaganib showing the greatest synergistic effect in combination with remdesivir," said Jeffrey Kugelman, Ph.D., Major(P), US Army MSC, Branch Chief Synthetic Biology & Surveillance, Molecular Biology Division, U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), who led the bioinformatics analysis of the study. "The results suggest that opaganib and upamostat may have potential or use in combination with direct antiviral agents, such as remdesivir, to improve treatment outcome, increasing efficacy while maintaining safety."

"Opaganib is believed to be the first host-directed molecule to show activity in Ebola virus disease, and these results add to a recent U.S. Army Ebola virus study in which opaganib delivered a statistically significant increase in mice survival time in vivo," said Reza Fathi, Ph.D., RedHill's SVP R&D. "Opaganib and RHB-107 are both novel, oral, host-directed, small molecule investigational drugs with demonstrated activity against multiple viral targets, including COVID-19, and are expected to be effective against emerging viral variants. This, together with their growing safety and tolerability databases, presents a compelling hypothesis for further study of their potential in treating Ebola virus."

Utilizing a checkerboard design to test the study compounds in combination, the study cell lines were pretreated and then infected with Ebola virus. The cells were fixed, washed and subjected to immunofluorescence staining using a virus-specific antibody. The raw data for the combination was analyzed to determine synergistic, additivity or antagonistic effects on viral inhibition while taking into account cell viability.

Twice daily administered opaganib has previously demonstrated benefit in late-stage clinical studies of patients hospitalized with moderate to severe COVID-19 and was selected by the NIH Radiation and Nuclear Countermeasures Program (RNCP) for Acute Radiation Syndrome development.

RHB-107 successfully met its U.S. Phase 2 study primary endpoint of safety and tolerability and delivered promising efficacy results, including marked reduction in hospitalization due to COVID-19. RHB-107 was recently accepted for inclusion in the ACESO PROTECT adaptive platform trial for early COVID-19 outpatient treatment. The 300-patient PROTECT Phase 2 RHB-107 arm, fully funded by non-dilutive external funding sources including the U.S. government[4], has received FDA clearance to start, with the first patient expected to be enrolled in the coming weeks. The study is being conducted in the U.S., Thailand, Ivory Coast, South Africa and Uganda, and is estimated to be completed by end of 2024.

About Ebola virus disease:
According to the Centers for Disease Control and Prevention, Ebola disease is a rare and often deadly illness, caused by infection by one of a group of four viruses, known as ebolaviruses, that are found primarily in sub-Saharan Africa and are known as: Zaire, Sudan, Taï Forest (formerly Côte d'Ivoire) and Bundibugyo. Transmission of the disease is mostly through contact with an infected animal (bat or nonhuman primate), or a sick or dead person infected with an ebolavirus. The course of the illness typically progresses from "dry" symptoms initially (such as fever, aches and pains, and fatigue), and then progresses to "wet" symptoms (such as diarrhea, vomiting and unexplained hemorrhaging, bleeding or bruising) as the person becomes sicker. There are currently only two FDA-approved therapies to treat EVD caused by the Ebola virus, species Zaire ebolavirus, in adults and children; Inmazeb™, a combination of three monoclonal antibodies and Ebanga™, a single monoclonal antibody. Both are intravenously infused direct acting monoclonal antibody antivirals that bind to glycoproteins on the Ebola virus's surface to prevent the virus from entering a person's cells. There is an urgent need for host-directed small molecule therapies that may be effective against multiple strains of ebolavirus, less likely to be impacted by viral mutation, and that are easy to store, distribute and administer, especially in areas where healthcare services and infrastructures may be sub-optimal.

About Opaganib (ABC294640)
Opaganib, a proprietary investigational host-directed and potentially broad-acting drug, is a first-in-class, orally administered sphingosine kinase-2 (SPHK2) selective inhibitor with anticancer, anti-inflammatory and antiviral activity, targeting multiple potential diseases, including gastrointestinal acute radiation syndrome (GI-ARS), COVID-19, other viruses as part of pandemic preparedness, and cholangiocarcinoma (bile duct cancer).

Opaganib's host-directed action is thought to work through the inhibition of multiple pathways, the induction of autophagy and apoptosis, and disruption of viral replication, through simultaneous inhibition of three sphingolipid-metabolizing enzymes in human cells (SPHK2, DES1 and GCS).

Opaganib was selected by the U.S. government's Radiation and Nuclear Countermeasures Program (RNCP), led by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, for the nuclear medical countermeasures product development pipeline as a potential treatment for Acute Radiation Syndrome (ARS).

Opaganib has received Orphan Drug designation from the FDA for the treatment of cholangiocarcinoma and has undergone studies in advanced cholangiocarcinoma (Phase 2a) and prostate cancer. Opaganib also has a Phase 1 chemoradiotherapy study protocol ready for FDA-IND submission.

Opaganib has demonstrated antiviral activity against SARS-CoV-2, multiple variants, and several other viruses, such as Influenza A. Being host-targeted, and based on data accumulated to date, opaganib is expected to maintain effect against emerging viral variants. In prespecified analyses of Phase 2/3 clinical data in hospitalized patients with moderate to severe COVID-19, oral opaganib demonstrated improved viral RNA clearance, faster time to recovery and significant mortality reduction in key patient subpopulations versus placebo on top of standard of care. Data from the opaganib global Phase 2/3 study has been submitted for peer review and recently published in medRxiv.

Opaganib has also shown positive preclinical results in renal fibrosis, and has the potential to target multiple oncology, radioprotection, viral, inflammatory, and gastrointestinal indications.

About RHB-107 (upamostat)
RHB-107 is a proprietary, first-in-class, once-daily orally administered investigational antiviral, that targets human serine proteases involved in preparing the spike protein for viral entry into target cells. Because it is host-cell targeted, RHB-107 is expected to also be effective against emerging viral variants with mutations in the spike protein. RHB-107 is well tolerated; in the initial COVID-19 study, among 41 patients only one reported a drug-related adverse reaction (a mild, self-limited, rash).

In addition, RHB-107 inhibits several proteases targeting cancer and inflammatory gastrointestinal disease. RHB-107 has undergone several Phase 1 studies and two Phase 2 studies, demonstrating its clinical safety profile in approximately 200 patients[5].

RedHill acquired the exclusive worldwide rights to RHB-107, excluding China, Hong Kong, Taiwan and Macao, from Germany's Heidelberg Pharmaceuticals (FSE: HPHA) (formerly WILEX AG) for all indications.

About USAMRIID
Since 1969, USAMRIID has served as the U.S. Department of Defense's lead laboratory for medical biological defense research. The core mission is to protect the warfighter from biological threats, while also investigating disease outbreaks and threats to public health. Research conducted at USAMRIID leads to medical solutions—therapeutics, vaccines, diagnostics, and information—that benefit both military personnel and civilians. USAMRIID is a subordinate laboratory of the U.S. Army Medical Research and Development Command.