On November 9, 2025 Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (the "Company," 6990.HK) reported results from multiple clinical studies on its TROP2 ADC sacituzumab tirumotecan (sac-TMT) as oral presentations. From November 6 to 9, the 2025 Chinese Congress on Holistic Integrative Oncology (CCHIO) was held in Kunming, Yunnan. This conference was jointly organized by the Chinese Anti-Cancer Association (CACA), the Tengchong Science Forum Organizing Committee Office, the World Association for Integrative Oncology (WAIO), and the China Institute for Integrative Medicine Development Strategy. Academicians, experts, and scholars from across the nation gathered to focus on innovations in cancer diagnosis and treatment while sharing scientific breakthroughs.
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KL264-01/MK-2870-001
On November 7, Professor Sheng Jindong from Tianjin Cancer Hospital presented oral results on the efficacy and safety of sacituzumab tirumotecan (sac-TMT) monotherapy for locally advanced or metastatic endometrial cancer (EC) in a Phase II study at the conference. The endometrial carcinoma (EC) cohort in this study enrolled a total of 158 patients, with 114 patients assigned to the sac-TMT 4 mg/kg group and 44 patients to the sac-TMT 5 mg/kg group.
At data cutoff (May 21, 2025), median (range) follow-up was 11.7 months in the 4 mg/kg group and 21.8 months in the 5 mg/kg group. Confirmed objective response rate (ORR) was 30.7% and 34.1% in the 4 mg/kg and 5 mg/kg groups; all responses were partial response (PR). Confirmed and unconfirmed ORR was 35.1% and 36.4% in the 4 mg/kg and 5 mg/kg groups. Median duration of response (DOR) was 9.3 months and 8.7 months in the 4 mg/kg and 5 mg/kg groups. Median progression free survival (PFS) was 6.0 months and 7.3 months in the 4 mg/kg and 5 mg/kg groups.
Grade ≥3 treatment-related AEs (TRAEs) occurred in 59 patients (51.8%) and 34 patients (77.3%) in the 4 mg/kg and 5 mg/kg groups respectively; Treatment-related AEs that led to treatment discontinuation was 2 and 1 patient in each group, respectively.
In patients with advanced EC, sac-TMT monotherapy showed promising antitumor activity in the ≥2L advanced/metastatic setting and manageable safety. Both the 4 mg/kg and 5 mg/kg groups exhibited manageable safety and tolerability profiles consistent with the known safety characteristics of sac-TMT. These data led to initiation of two ongoing global Phase 3 studies of sac-TMT 4 mg/kg Q2W in advanced EC, which were sponsored and led by MSD.
OptiTROP-Lung03
On November 8, Professor Fang Wenfeng from the Cancer Center of Sun Yat-sen University delivered an oral presentation at the conference on preliminary results from a Phase II study evaluating sac-TMT in treating locally advanced or metastatic non-small cell lung cancer (NSCLC) harboring uncommon EGFR mutations in previously treated patients. As of Dec 01, 2024, 42 patients were enrolled, including 23 patients with EGFR uncommon non-ex20ins mutations and 19 patients with EGFR ex20ins. Patients received sac-TMT 5 mg/kg Q2W until disease progression or unacceptable toxicity. After a median follow-up of 9.9 months, the ORR was 35.7% (15/42, 3 pending confirmation). The disease control rate (DCR) was 85.7%. Responses were durable with the median duration of response (mDoR) not yet reached, and the 6-month DoR rate was 90.9%. The median progression-free survival (mPFS) was 9.5 months (95% CI: 5.6, 10.9).
In the subset of patients with uncommon non-ex20ins, the ORR was 34.8% (8/23, 1 pending confirmation); the mPFS was 10.9 months (95% CI: 5.6, NE). In the subset of patients with ex20ins, the ORR was 36.8% (7/19, 2 pending confirmation); the mPFS was 9.0 months (95% CI: 2.4, NE). Grade ≥3 treatment-related adverse events occurred in 52.4% of pts. No TRAE led to treatment discontinuation or death. No cases of interstitial lung disease/pneumonitis were reported.
Sac-TMT monotherapy demonstrated promising clinical activity with a manageable safety profile in previously treated advanced NSCLC patients with uncommon EGFR mutations. These findings warrant further investigation of sac-TMT as a potential therapy for this population.
OptiTROP-Lung01
Professor Fang Wenfeng also presented results from the non-squamous cohort in the Phase II study evaluating the combination of sac-TMT and tagitanlimab (anti-PD-L1) as first-line therapy for advanced NSCLC during the oral presentation session. As of Dec 30, 2024, 81 patients with non-squamous histology were enrolled. Patients receive sac-TMT (5 mg/kg Q3W or Q2W) plus tagitanlimab (1200 mg Q3W or 900 mg Q2W) until disease progression or unacceptable toxicity. After median follow-up of 17.1 months, the confirmed ORR was 59.3%; The DCR was 91.4%; mDOR was 16.5 months (95% CI: 11.7, 22.1); mPFS was 15.0 months (95% CI: 10.8, 24.8). Among pts with PD-L1 TPS< 1%, the confirmed ORR was 47.1%; mPFS was 12.4 months (95%CI: 7.6, 15.4); while for patients with PD-L1 TPS≥ 1%, the confirmed ORR was 68.1%; mPFS was 17.8 months (95%CI: 14.5, NE). Among patients with PD-L1 TPS≥ 50%, the confirmed ORR was 77.8%; mPFS was 17.8 months (95% CI: 10.8, NE). No TRAE led to treatment discontinuation or death.
Sac-TMT in combination with tagitanlimab demonstrated promising antitumor activity in treatment-naive advanced non-squamous NSCLC. The durable clinical activities were observed regardless of PD-L1 expression. This combination therapy showed a tolerable safety profile based on known profiles of the individual agents, with no new safety signals observed.
Currently, two Phase 3 registrational studies of sac-TMT, namely (i) sac-TMT in combination with pembrolizumab (KEYTRUDA1) versus pembrolizumab for first-line treatment of patients with PD-L1 positive locally advanced or metastatic NSCLC, and (ii) sac-TMT in combination with pembrolizumab versus chemotherapy combined with pembrolizumab as first-line treatment for patients with PD-L1 negative locally advanced or metastatic non-squamous NSCLC are in progress.
With the goal of addressing patients’ urgent clinical needs, Kelun-Biotech has initiated over 30 clinical studies across multiple disease areas including lung cancer, breast cancer, and gynecological tumors. Leveraging its proprietary ADC and novel DC platform, OptiDC, the Company will continue developing innovative drugs with significant clinical value. This commitment aims to further enhance patient outcomes and contribute corporate strength to advancing the Healthy China initiative.
About Sac-TMT
Sac-TMT, a core product of the Company, is a novel human TROP2 ADC in which the Company has proprietary intellectual property rights, targeting advanced solid tumors such as NSCLC, breast cancer (BC), gastric cancer (GC), gynecological tumors, among others. Sac-TMT is developed with a novel linker to conjugate the payload, a belotecan-derivative topoisomerase I inhibitor with a drug-to-antibody-ratio (DAR) of 7.4. Sac-TMT specifically recognizes TROP2 on the surface of tumor cells by recombinant anti-TROP2 humanized monoclonal antibodies, which is then endocytosed by tumor cells and releases the payload KL610023 intracellularly. KL610023, as a topoisomerase I inhibitor, induces DNA damage to tumor cells, which in turn leads to cell-cycle arrest and apoptosis. In addition, it also releases KL610023 in the tumor microenvironment. Given that KL610023 is membrane permeable, it can enable a bystander effect, or in other words kill adjacent tumor cells.
In May 2022, the Company licensed the exclusive rights to MSD (the tradename of Merck & Co., Inc., Rahway, NJ, USA) to develop, use, manufacture and commercialize sac-TMT in all territories outside of Greater China (includes Mainland China, Hong Kong, Macau, and Taiwan).
To date, three indications for sac-TMT have been approved and marketed in China for the treatment of adult patients with unresectable locally advanced or metastatic triple negative breast cancer (TNBC) who have received at least two prior systemic therapies (at least one of them for advanced or metastatic setting), EGFR mutation-positive locally advanced or metastatic non-squamous NSCLC following progression on EGFR-TKI therapy and platinum-based chemotherapy and EGFR mutant-positive locally advanced or metastatic non-squamous NSCLC who progressed after treatment with EGFR-TKI therapy. Sac-TMT is the first TROP2 ADC drug approved for marketing in lung cancer globally. In addition, the new indication application for sac-TMT for the treatment of adult patients with unresectable locally advanced, metastatic hormone receptor positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) BC who have received prior endocrine therapy and other systemic treatments in the advanced or metastatic setting was accepted by the Center for Drug Evaluation of the NMPA, and was included in the priority review and approval process.
As of today, the Company has initiated 9 registrational clinical studies in China. MSD has initiated 15 ongoing Phase Ⅲ global clinical studies of sac-TMT as a monotherapy or with pembrolizumab or other anti-cancer agents for several types of cancer. These studies are sponsored and led by MSD.
(Press release, Kelun, NOV 9, 2025, View Source [SID1234659674])