The FDA has accepted the Investigational New Drug application for TX803, a novel treatment for colorectal cancer. TX803 is a first-in-class small molecule therapeutic that inhibits the PI3K/AKT pathway through a novel mechanism by targeting, not the kinase itself, but a PI3K-activating oncoprotein, the truncated retinoid X receptor-alpha (tRXR[alpha]).
Moreover, tRXR[alpha] is found in high levels in tumor tissues obtained from a significant portion of colorectal, gastric, and breast cancer patients. Preclinical studies have demonstrated that TX803 is orally bioavailable, well-tolerated, and efficacious in several animal tumor models, including KRAS-mutated colorectal cancer.
"Approximately 50 percent of colorectal cancer patients have tumors with a KRAS or NRAS mutation, which renders them resistant to anti-EGFR therapies, such as cetuximab and panitumumab. If clinically proven, TX803 has the potential to address a significant unmet need in treating RAS-mutated colorectal and possibly other type of cancers," said Kimmie Ng, MD, MPH, Director of Clinical Research, Center for Gastrointestinal Oncology at Dana-Farber Cancer Institute, Harvard Medical School, Boston, and principal investigator for TX803 clinical trials.