13.04.2021
TEL AVIV, Israel, April 13, 2021 (GLOBE NEWSWIRE) -- Purple Biotech Ltd. ("Purple Biotech" ", or the "Company") (NASDAQ/TASE: PPBT), a clinical-stage company developing first-in-class, effective and durable therapies by overcoming tumor immune evasion and drug resistance, today announced that additional preclinical data supporting the mechanism of action of NT219, a dual inhibitor, novel small molecule that simultaneously targets IRS1/2 and STAT3, were presented in a poster entitled "Adaptation of colorectal cancer cells to the brain microenvironment: The role of IRS2," at the American Association of Cancer Research (AACR) 2021 Annual Meeting. These data update and expand on the results previously reported by the Company from its collaboration with Professor Ido Wolf, Head of the Oncology Division at Tel Aviv Sourasky Medical Center.
Colorectal cancer (CRC) represents the fourth most frequent cause of brain metastasis, which is the most common brain tumor. The study included an analysis of more than 16,000 human CRC local and metastasis samples, and revealed increased amplification of IRS2 in brain metastases.
In an in vitro system mimicking the brain microenvironment, IRS2-overexpressed CRC cells showed prolonged survival. Importantly, transcriptomic analysis demonstrated significant enrichment of the oxidative phosphorylation (OXPHOS) pathway by IRS2. CRC cells expressing IRS2 showed increased mitochondrial activity and glycolysis-independent viability. Inhibition of IRS2 using NT219 dose-dependently inhibited IRS2-expressing cells viability and OXPHOS genes expression.
The Wnt/β-catenin pathway was among the most significantly enriched pathways in the brain metastasis, as IRS2-expressing cells showed increased transcriptional activity of the β-catenin. In addition, NT219 decreased the transcriptional activity of β-catenin in IRS2-expressing CRC cells to a greater extent than AKT and PI3K inhibitors, and most significantly suggested relevance of IRS2 in activating β-catenin. It was further shown that 5-FU, a chemotherapy approved for treating CRC, elevated β-catenin expression, and that NT219 diminished both 5FU-induced and the basal level of the β-catenin expression. Utilizing an intracranial animal model, it was also demonstrated that while 5-FU alone had no significant effect, the combination of 5-FU and NT219 significantly inhibited the formation of brain metastasis and extended survival rates of the study mice.
"We are excited about these highly encouraging study results," said Bertrand Liang, M.D., Ph.D., Chief Medical Officer of Purple Biotech. "These compelling data provide important insights regarding the role of IRS2 in promoting CRC brain metastasis, and suggest that novel agents such as NT219 have the potential to effectively inhibit the development of brain metastasis. Our ongoing Phase 1/2 clinical trial of NT219 as monotherapy for the treatment of solid tumors, followed by a dose escalation of NT219 in combination with cetuximab, an epithelial growth factor receptor (EGFR) blocking monoclonal antibody, for the treatment of recurrent and/or metastatic solid tumors and squamous cell carcinoma of the head and neck cancer, is proceeding with enrollment as planned and we continue to expect the availability of top-line data from the first part of this study in the second half of this year."
The poster presentation is available at https://purple-biotech.com/2021/04/12/...irtual-meeting-poster-2021/.
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