#China #Chengdu #Kelun-Biotech #Sacituzumab #Urothelial Carcinoma

Promising Phase II Study Results of Sacituzumab Tirumotecan for Advanced Urothelial Carcinoma

On November 25, 2025, the Annals of Oncology published a significant study conducted by Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. on the efficacy of sacituzumab tirumotecan (sac-TMT) as a monotherapy treatment for advanced or metastatic urothelial carcinoma (UC). This innovative treatment has shown remarkable results, which could reshape the therapeutic landscape for patients facing this challenging cancer.

Study Overview

The study focuses on cohort 9 from the Phase II MK-2870-001/KL264-01 trial, which assessed sac-TMT's effectiveness in patients who have experienced disease progression after previous chemotherapy and immune checkpoint inhibitors. Notably, sac-TMT employs an innovative irreversible conjugation technology alongside a unique topoisomerase I inhibitor, KL610023 (T030), which enhances the release of the toxin specifically at the tumor sites. This novel approach aims to increase the therapeutic potency while minimizing side effects, making it a potentially game-changing treatment option for patients with advanced UC.

Key Findings

The findings from the trial are compelling. A total of 49 patients, many of whom had previously received two or more lines of therapy, were treated with sac-TMT at a dose of 5 mg/kg every two weeks. The results reflected a confirmed objective response rate (ORR) of 31%, with the second-line therapy demonstrating an impressive ORR of 50%. Moreover, disease control was achieved in 71% of participants, showcasing the treatment's ability to manage advanced disease effectively.
Notably, the median duration of response (DOR) was not reached, indicating a potentially robust and sustained therapeutic effect, and the 12-month probability of maintaining a response was 53%. The median progression-free survival (PFS) was documented at 5.5 months, with 29% of patients maintaining PFS at the one-year mark.

In terms of safety, sac-TMT was generally well tolerated. The most common treatment-related adverse events categorized as grade 3 or 4 were hematologic toxicities and stomatitis, with no occurrences of febrile neutropenia or grade 5 events, highlighting the manageable safety profile of this treatment.

Clinical Implications

Professor Ye Dingwei, Vice President of Fudan University Shanghai Cancer Center, emphasized that traditional chemotherapy options have shown limited efficacy for advanced or drug-resistant UC. He noted the importance of innovative therapies like ADCs (antibody-drug conjugates) as they provide new avenues for patients who have previously exhausted standard treatment options. The promising clinical outcomes associated with sac-TMT indicate a vital step forward in personalized medicine for patients with challenging cancer profiles.

About Sacituzumab Tirumotecan

Sac-TMT is considered a cornerstone in Kelun-Biotech's portfolio, designed to target multiple advanced solid tumors including non-small cell lung cancer (NSCLC) and gastric cancer. The drug specifically targets TROP2 on tumor cells, allowing for targeted therapy that capitalizes on the tumor microenvironment to exert its effects. With the development of sac-TMT, Kelun-Biotech has established itself as a pioneer in the development of innovative drugs tailored for significant medical needs.

Following its licensing agreement in May 2022 with MSD (Merck & Co.), sac-TMT is already commercially available in China for implications beyond UC, including triple-negative breast cancer and other significant malignancies. These approvals signify the growing need for innovative solutions in oncology, especially for patients who face limited therapeutic options.

Conclusion

The publication of these Phase II clinical trial results in the Annals of Oncology marks an exciting moment in the fight against advanced urothelial carcinoma. The effectiveness and manageable safety of sac-TMT monotherapy present new hope for patients battling this aggressive form of cancer, potentially altering treatment landscapes and improving patient outcomes. As further studies are initiated, the oncology community remains optimistic about the future of targeted treatments like sac-TMT in their quest to overcome cancer's challenges.