China's First Innovative Drug for Precision Postoperative Assessment of Differentiated Thyroid Cancer—Recombinant Human Thyrotropin Beta (ZeSuNing®)—Dispenses First Prescriptions Nationwide

Recently, the first prescriptions for China’s first innovative drug for precise postoperative assessment of differentiated thyroid cancer, recombinant human thyrotropin beta for injection (Zesuning®), were issued at the First Affiliated Hospital, Zhejiang University School of Medicine, and Jiangsu Province People’s Hospital.

Thyroid cancer is one of the solid tumors with a rapidly increasing incidence in recent years. Differentiated thyroid cancers, such as papillary and follicular carcinomas, account for more than 90% of cases and generally have a favorable prognosis, with a 10-year survival rate exceeding 90%. However, a “high survival rate” does not mean “no management is needed.” Studies show that approximately 10%–30% of patients still face the risk of recurrence or metastasis during postoperative follow-up. Therefore, regular and standardized postoperative follow-up to monitor for any residual disease or signs of recurrence is crucial for improving the long-term quality of life for these patients.

For patients who have undergone total thyroidectomy for differentiated thyroid cancer, stimulated thyroglobulin (sTg) testing and radioactive iodine whole-body scanning (WBS) are important tools for precise assessment. To prepare for these tests, patients must discontinue thyroid hormone replacement therapy in advance to elevate endogenous thyroid-stimulating hormone (TSH) levels. During the withdrawal period, patients rapidly develop a hypothyroid state, experiencing a series of symptoms such as fatigue, cold intolerance, depressed mood, sluggish responsiveness, and facial edema. These symptoms significantly impair daily work, life, and emotional well-being. Some patients even postpone or forgo follow-up examinations due to an inability to tolerate hormone withdrawal, leading to poor follow-up compliance and hindering the early detection of recurrence.

The clinical application of the innovative drug recombinant human thyroid-stimulating hormone beta for injection not only provides a more patient-friendly assessment option for the large number of postoperative thyroid cancer patients requiring long-term follow-up, but also propels China’s long-term follow-up management for postoperative thyroid cancer into a new phase characterized by greater standardization and a patient-centered approach.

As early as June 2025, Merck entered into a collaboration agreement with Zelgen, securing exclusive commercialization rights in mainland China for Zelgen’s independently developed recombinant human thyroid-stimulating hormone (rhTSH) for injection. Commenting on the successful dispensing of the first prescription, Andreas Mu, Managing Director of Merck Healthcare China, stated: “The successful dispensing of the first prescription for recombinant human TSH-β marks a significant milestone in Merck’s deep commitment to the field of thyroid diseases and its dedication to serving patients in China. It signifies an important step forward in our post-operative management of thyroid cancer. This achievement also represents a key practice of leveraging Merck’s professional expertise in thyroid diseases and partnering with Zelgen, a local Chinese innovator, to facilitate the implementation of innovative solutions in the domestic market. As a global leader in the field of thyroid diseases, Merck will further leverage its advantages across the entire industry chain to accelerate the adoption of innovative outcomes, continuously refine its comprehensive disease management portfolio for thyroid conditions, and consolidate its leading market position. We remain steadfast in our long-term commitment to ‘Uniting for Patients,’ driving innovation to support the ‘Healthy China 2030’ strategy and contribute value to the development of China’s healthcare sector.”

Dr. Sheng Zelin, Chairman and General Manager of Zelgen, stated: “Recombinant Human Thyrotropin Beta for Injection is a high-quality novel complex recombinant protein drug independently developed by Zelgen and manufactured using continuous perfusion technology. It is the first recombinant human thyrotropin approved in China for adjunctive diagnostic use in postoperative thyroid cancer patients, and marks the fourth new drug approved for marketing by Zelgen. The successful initial launch of Recombinant Human Thyrotropin Beta for Injection was made possible through the collaborative efforts of the Zelgen and Merck teams. In 2024, the number of new thyroid cancer cases in China reached 466,100, elevating it to the third most prevalent cancer type in the country. We sincerely hope that Recombinant Human Thyrotropin Beta for Injection will further improve the long-term survival rates of thyroid cancer patients in China. Zelgen remains committed to making more high-quality innovative drugs of Chinese origin accessible to a broader patient population.”