Regor Therapeutics Submits First Clinical Application in China for Novel CDK2/4/6 Inhibitor RGT-419B

On February 11, the CDE official website showed that Regor Therapeutics' CDK2/4/6 inhibitor RGT-419B was submitted for clinical trial in China for the first time. On December 28, the drug had just received FDA approval for clinical trials.

RGT-419B is a next-generation small molecule inhibitor of CDK2/4/6 with an optimized kinase activity profile. It has the potential to improve the safety of currently approved CDK4/6 inhibitors and overcome resistance to these inhibitors, which are used in combination with endocrine therapy to treat premenopausal/postmenopausal patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer.

In cellular model experiments, RGT-419B demonstrated single-agent activity and showed greater inhibition of ER+ tumor cell growth compared to abemaciclib and palbociclib. In ER+ breast cancer cells resistant to currently approved CDK4/6 inhibitors, RGT-419B exhibited complete suppression of cancer cell proliferation. In these experiments, the inhibitory effect of RGT-419B on tumor cells was further enhanced when combined with selective estrogen receptor degraders or PI3K signaling pathway inhibitors.

RGT-419B will initially be developed for the treatment of HER2-, ER+ breast cancer patients with primary or acquired resistance to currently approved CDK4/6 inhibitors, both as a single agent and in combination with other approved therapies. As CDK4/6 inhibitors are widely adopted in clinical practice, refractory and relapsed patients previously treated with CDK4/6 inhibitors are becoming a larger, clinically significant unmet medical need. The clinical development program of RGT-419B will address this resistance to CDK4/6 and other hormone receptor modulating therapies, providing new opportunities to improve survival and quality of life for patients with advanced breast cancer.

RGT-419B is the first of many innovative oncology drugs being developed by Regor Therapeutics. Dr. Xia Yang Qiu, founder and CEO, said: "This milestone marks Regor Therapeutics' successful entry into the field of cancer treatment. Using our self-developed AI-assisted drug discovery platform, CARD, we have identified optimal selectivity across multiple CDKs, successfully advancing this novel drug into clinical development in the United States. We are also very excited about the opportunity to bring a new differentiated treatment option to breast cancer patients worldwide."

HER2-/HR+ Breast Cancer is the Most Common Type of Breast Cancer. Globally, breast cancer is one of the most prevalent cancers, affecting approximately 2.3 million women in 2020 and serving as the leading cause of cancer-related deaths among women. In China, breast cancer ranks fourth among solid tumor types, with over 400,000 new cases annually. Breast cancer imposes a significant healthcare burden on patients in China and worldwide, while also bringing substantial negative impacts to patients and their families.

Regor Therapeutics is a clinical-stage biopharmaceutical high-tech company. In the three and a half years since its establishment, it has utilized its AI-assisted new drug discovery CARD platform to target "long-unconquered" targets in the pharmaceutical industry and develop innovative drugs with clinically differentiated advantages. The company focuses on three major therapeutic areas: oncology, immunology, and metabolism. Currently, it has three new drugs in clinical stages, with RGT-075 being the most advanced. This small molecule GLP-1R agonist has entered Phase II clinical trials and is among the global first-tier. On December 10, 2021, Eli Lilly collaborated with Regor Therapeutics for up to $1.5 billion to jointly develop new drugs in the metabolic field, with the key project being RGT-075 for diabetes and obesity.

Regor Therapeutics Pipeline

However, in early February, Pfizer sued two founders of Regor Therapeutics, accusing them of stealing the company's trade secrets while working at Pfizer. Pfizer claimed that the drugs launched by the defendants were "strikingly similar" to its own and had been patented. Currently, the lawsuit has been accepted by the Federal Court of Connecticut, USA. The focus of the lawsuit is on the GLP-1R small molecule agonist RGT-075. Pfizer also has a similar drug, PF-06882961. Regor Therapeutics stated that it believes the lawsuit is completely baseless and will actively defend itself.