RedHill Biopharma Ltd. (Nasdaq: RDHL) announced today that the China National Intellectual Property Administration (CNIPA) has formally allowed a critical use of composition-of-matter patent for its investigational COVID-19 treatment, RHB-107 (upamostat).
The patent approval significantly strengthens RedHill's intellectual property portfolio in Asia, providing broad protection for the molecular structure of RHB-107 in oral formulations targeting SARS-CoV-2 infections, including both wild-type and emerging variants.
"This newly allowed Chinese patent application is a significant success, enhancing RedHill's strategic positioning in the global COVID-19 therapeutic space – a market still expected to be worth more than three billion dollars in 2025," said Guy Goldberg, RedHill's Chief Business Officer. "It provides broad and robust protection of the use of RHB-107, including its structure in oral formulations targeting SARS-CoV-2 infections."
Promising Clinical Results
RHB-107 has shown impressive efficacy in its U.S. Phase 2 study, results of which were published in the International Journal of Infectious Diseases. The trial demonstrated a 100% reduction in hospitalization due to COVID-19, with zero patients (0/41) on the RHB-107 arms requiring hospitalization compared to 15% (3/20) of patients in the placebo-controlled arm (nominal p-value=0.0317).
Additionally, the study revealed an approximately 88% reduction in reported new severe COVID-19 symptoms after treatment initiation. Only 2.4% of patients in the RHB-107 treated group (1/41) reported new severe COVID-19 symptoms, compared to 20% (4/20) of patients in the placebo-controlled arm (nominal p-value=0.036).
Post-hoc analysis further demonstrated faster recovery periods from severe COVID-19 symptoms, with a median of 3 days to recovery with RHB-107 compared to 8 days with placebo.
Novel Mechanism of Action
What distinguishes RHB-107 from other COVID-19 treatments is its unique mechanism of action. As a host-directed antiviral, it targets human serine proteases involved in preparing the spike protein for viral entry into target cells, rather than targeting the virus directly.
"As a novel, potentially broad-acting, host-directed antiviral that is expected to act independently of viral spike protein mutations, RHB-107, if approved, could provide a much-needed additional option for use in the early COVID-19 treatment space, alongside Pfizer's Paxlovid," Goldberg explained.
This approach suggests RHB-107 may remain effective against emerging viral variants with mutations in the spike protein, addressing a critical challenge in COVID-19 treatment as the virus continues to evolve.
Safety Profile and Administration
RHB-107 has demonstrated a favorable safety profile in clinical trials. In the initial COVID-19 study, among 41 patients, only one reported a drug-related adverse reaction (a mild, self-limited rash). The compound has undergone several Phase 1 studies and two Phase 2 studies, demonstrating its clinical safety profile in approximately 200 patients.
The drug is administered orally once daily, making it a patient-friendly option for early, community-based (non-hospitalized) treatment of COVID-19.
Broader Therapeutic Potential
Beyond COVID-19, RHB-107 inhibits several proteases targeting cancer and inflammatory gastrointestinal disease, suggesting potential applications beyond viral infections. RedHill acquired the exclusive worldwide rights to RHB-107, excluding China, Hong Kong, Taiwan, and Macao, from Germany's Heidelberg Pharma AG for all indications.
Future Developments
Additional clinical data is expected from the externally non-dilutive funded PROTECT study, supported by the U.S. Department of Defense. This data will further elucidate RHB-107's efficacy and safety profile.
The COVID-19 therapeutic market is projected to remain substantial, with an expected value exceeding $3 billion in 2025, according to market research. As COVID-19 continues to pose a threat, particularly to vulnerable populations, effective oral treatments for early intervention remain a critical need in the global healthcare landscape.
About RedHill Biopharma
RedHill Biopharma Ltd. is a specialty biopharmaceutical company primarily focused on U.S. development and commercialization of drugs for gastrointestinal diseases, infectious diseases, and oncology. The company promotes the FDA-approved gastrointestinal drug Talicia for the treatment of Helicobacter pylori infection in adults and has several late-stage development programs in its pipeline.
RedHill's development portfolio includes opaganib, a first-in-class sphingosine kinase-2 selective inhibitor; RHB-204, an antibiotic therapy for nontuberculous mycobacterial disease; RHB-104 for Crohn's disease; and RHB-102 for various gastrointestinal conditions.
