On May 6th, the National Medical Products Administration (NMPA) officially approved the world’s first CDK2/4/6 inhibitor, Coumoxili Capsules (Saitanxin), independently developed by China’s biopharmaceutical subsidiary, Zhengda Tianqing Pharmaceutical Group ®） It is a new indication, and is used in combination with fluoxetine for the initial treatment of locally advanced or metastatic breast cancer patients with hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative.

This is the first line treatment qualification of Kumosili in a few months after it was approved as a second-line indication in December 2025, marking the historic leap from “following” to “leading the world” in the field of precision treatment of breast cancer with China’s original innovative drugs. As one of the core clients of Beijing Zhizhongdeben Intellectual Property Agency Co., Ltd., Zhengda Tianqing continues to make breakthroughs in the field of innovative cancer drugs. The approval of the new drug indications is also another witness to the innovative strength of domestic pharmaceutical companies at the source.

1、 Existing pain points and unmet needs in clinical treatment of breast cancer

Breast cancer has ranked first in the incidence rate of malignant tumors among women in the world and China for many consecutive years, and can be called the “first killer of women’s health”. According to the data of the International Cancer Research Institute, there are nearly one million new cases of breast cancer in the world every year, and nearly 400000 new cases in China every year, of which the HR+/HER2- subtype accounts for 65% -70%, which is the most mainstream clinical type of breast cancer.

In recent years, CDK4/6 inhibitor combined with endocrine therapy has become the first-line standard scheme for this subtype of advanced breast cancer, greatly rewriting patients’ survival expectations, but two core problems in clinical application are always difficult to solve:

One is the dilemma of drug resistance. About 30% -40% of patients develop resistance within 1-2 years of medication, and compensatory activation of the CDK2 pathway is a key resistance mechanism that traditional single target drugs cannot block.

The second is the safety shortcoming. Traditional CDK4/6 inhibitors have a prominent risk of bone marrow suppression, with an incidence of grade ≥ 3 neutropenia exceeding 50%, seriously affecting treatment compliance and long-term medication safety.

2、 Global pioneering mechanism: Triple targets break through the limitations of traditional treatments

The birth of Zhengda Tianqing Kumoxil is the world’s first breakthrough targeting this clinical pain point. As the world’s first approved triple selective inhibitor of CDK2/4/6, kumoxili breaks through the traditional single target development approach and innovatively achieves synergistic inhibition of the three major kinases CDK2, CDK4, and CDK6

Strong blockade: efficiently inhibits CDK4/6 core proliferation signals, and suppresses tumor cell proliferation from the source

Precise inhibition of drug-resistant targets: Simultaneously inhibiting CDK2, blocking tumor cell escape pathways, effectively delaying or even overcoming traditional CDK4/6 inhibitor resistance

Better safety: The molecular structure has been optimized to selectively reduce the inhibitory effect on CDK6, while ensuring anti-tumor activity, significantly reducing adverse reactions such as bone marrow suppressionThis mechanism innovation allows Kumosili to completely break away from the limitations of traditional drugs and provide a new solution for HR+/HER2- breast cancer treatment.

3、 The clinical data is impressive, and the first-line indication strength has been approved

The first-line indication approval this time is based on the hardcore data support of the CULMINATE-2 global multicenter phase III clinical study, and the research results demonstrate excellent clinical value. This study included the global multi center HR+/HER2- locally advanced or metastatic breast cancer patients for initial treatment. Head to head comparison of the efficacy and safety of kumoxil combined with fluoxetine and placebo combined with fluoxetine.

The efficacy data shows that:

The objective response rate (ORR) of the experimental group reached 59.3%, significantly higher than the control group’s 42.3%. The risk of disease progression or death was reduced by 44%, effectively prolonging the progression free survival of patients;

Security data shows:

The incidence of grade ≥ 3 neutropenia is only 20.3%, far lower than that of traditional drugs. The treatment termination rate due to adverse events is only 3.5%. Long term medication safety is controllable and easy to manage.

More noteworthy is that kumoxili has shown stable benefits in high-risk populations such as visceral metastasis and premenopausal patients, filling the therapeutic gap of traditional drugs in high-risk populations and providing a new treatment option for more complex cases.

4、 Perfect pipeline layout to build a whole course treatment matrix for breast cancer

The rapid breakthrough from second tier to first tier demonstrates the strong research and development capabilities and clinical translation efficiency of Zhengda Tianqing. In December 2025, Kumosili was approved for the first time as a second-line indication for HR+/HER2- advanced breast cancer patients who had previously progressed in endocrine therapy. Based on the data of the CULMINATE-1 study, the median progression free survival period reached 16.62 months, significantly extending 9.16 months compared with the control group, reducing the risk of disease progression by 64%, and rapidly benefiting thousands of patients.

Now the first line indication has been approved, which means that Kumosilide can cover the whole cycle scenario of HR+/HER2- advanced breast cancer from initial treatment to later line treatment. At the same time, the phase III clinical research on adjuvant treatment for early breast cancer has been completed and is steadily promoting follow-up. It is expected to further expand to the field of early breast cancer in the future, and build a treatment matrix covering the whole course of disease. In addition to Kumosili, Chia Tai Tianqing has also distributed TQB3126, TQB3122, TQB2101 and other differentiated products in the field of breast cancer, forming a full classification and full cycle product pipeline, and continuously consolidating the leading position in the field of tumor treatment.

5. Conclusion

The successful approval of Kumosili’s first-line indication is not only a powerful demonstration of Zhengda Tianqing’s ability to deeply cultivate the innovative track of cancer, but also an important breakthrough in China’s innovative drug industry – this world’s first CDK2/4/6 inhibitor, which solves the clinical drug resistance and safety problems with mechanism innovation, reshapes the HR+/HER2- breast cancer treatment pattern with hard core data, and makes China’s original research drugs make a loud voice in the global cancer treatment field.

As a long-term intellectual property partner of Zhengda Tianqing, MeritsIP always adheres to the development concept of “cultivating virtue in the heart and building trust in action”, and continues to pay attention to the cutting-edge layout and research and development process of the enterprise in the field of biopharmaceutical innovation. The barriers to innovation and research and development in biomedicine are high and the cycle is long. A sound intellectual property layout is an important cornerstone for enterprises to maintain innovation value.

In the future, MeritsIP will continue to empower innovation with professionalism, safeguard value with service, and work side by side with ethnic pharmaceutical companies such as Zhengda Tianqing to promote more innovative Chinese drugs to benefit global patients, contributing to the construction of a healthy China and the development of global pharmaceutical innovation!

---

About Us

MeritsIP: Your Global Intellectual Property Partner

At MeritsIP, we provide comprehensive IP services in biomedicine, medical devices, manufacturing, semiconductors, and AI. We support 200+ top clients globally with strategic, high-quality IP services.

Stay Connected

• • Website: https://www.meritsipglobal.com

• • LinkedIn: Follow us on LinkedIn

• • Email: meritsip@meritsandtree.com

© 2025 MeritsIP. All Rights Reserved.