By Fineline Cube 
Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (HKG: 6990) announced the official China launch of trastuzumab botidotin, its innovative HER2‑targeted antibody‑drug conjugate (ADC), following NMPA approval on 17 Oct 2025. The drug is positioned to challenge T‑DM1 in HER2‑positive metastatic breast cancer after demonstrating superior PFS in a head‑to‑head Phase III trial.
Commercial Launch Milestone
| Item | Detail |
|---|---|
| Product | trastuzumab botidotin (HER2 ADC) |
| Company | Kelun‑Biotech (6990.HK) |
| Approval Date | 17 Oct 2025 (NMPA) |
| Launch Date | 19 Nov 2025 (China market) |
| Indication | HER2‑positive unresectable or metastatic breast cancer (post‑trastuzumab + taxane) |
| Competitor Benchmark | Head‑to‑head vs trastuzumab emtansine (T‑DM1) |
Drug Profile
- Class: Investigational HER2‑targeted ADC developed entirely by Kelun‑Biotech
- Mechanism: Delivers cytotoxic payload directly to HER2‑overexpressing tumor cells
- Differentiation: First Chinese‑developed HER2 ADC to launch with Phase III head‑to‑head superiority data vs. established standard of care (T‑DM1)
- Intellectual Property: Global patents held by Kelun‑Biotech; no disclosed out‑licensing agreements
Clinical Evidence – KL166-Ⅲ-06 Phase 3 Trial
| Endpoint | Trastuzumab Botidotin | T‑DM1 Control | Relative Benefit |
|---|---|---|---|
| Median PFS | 11.1 months | 4.4 months | +6.7 months |
| PFS HR | 0.39 (61% risk reduction) | – | p<0.0001 |
| Objective Response Rate (ORR) | 76.9% | – | Superior vs historical T‑DM1 data (~40‑45%) |
The trial enrolled HER2‑positive unresectable/metastatic breast cancer patients who progressed after prior trastuzumab and taxane‑based therapy.
Market Impact & Outlook
- China HER2+ Breast Cancer Market: ~60,000 new cases annually; ~30% develop metastatic disease eligible for ADC therapy
- T‑DM1 Current Share: T‑DM1 (Kadcyla) holds ~40% of second‑line HER2+ metastatic market in China, with estimated 2025 sales of ¥2.5 billion (~US$340 million)
- Pricing Strategy: Kelun‑Biotech is expected to price trastuzumab botidotin at a 15‑20% discount to T‑DM1, capturing cost‑sensitive hospitals while leveraging superior efficacy data
- Revenue Forecast: Analysts project trastuzumab botidotin could achieve ¥1.2‑1.8 billion (~US$165‑245 million) in China peak sales by 2030, assuming 25‑30% market share capture in second‑line HER2+ metastatic setting
- Competitive Landscape: Faces competition from AstraZeneca/Daiichi’s ENHERTU (HER2 ADC) and Jiangsu Alphamab’s ARX788, but head‑to‑head T‑DM1 data provides strong differentiation for prescribers
- Next Steps: Kelun‑Biotech plans to submit for National Reimbursement Drug List (NRDL) inclusion in 2026; global expansion discussions are underway with potential partners for US/EU markets
Forward‑Looking Statements
This brief contains forward‑looking statements regarding trastuzumab botidotin’s commercial launch performance, market penetration, and revenue projections. Actual results may differ materially due to risks including market acceptance, reimbursement negotiations, competitive responses, and regulatory changes.-Fineline Info & Tech