By Fineline Cube 
Sichuan Kelun‑Biotech Biopharmaceutical Co., Ltd. (HKG: 6990) announced that sacituzumab tirumotecan (sac‑TMT, SKB264/MK‑2870), its TROP2‑directed ADC, in combination with MSD’s pembrolizumab (KEYTRUDA), has been granted Breakthrough Therapy Designation (BTD) by China’s Center for Drug Evaluation (CDE) for first‑line treatment of locally advanced or metastatic NSCLC (PD‑L1 TPS ≥1%, EGFR‑negative, ALK‑negative).
Breakthrough Designation & Clinical Basis
| Item | Detail |
|---|---|
| Product | Sacituzumab tirumotecan (sac‑TMT, SKB264/MK‑2870) |
| Company | Sichuan Kelun‑Biotech (6990.HK) |
| Partner | MSD (Merck) for pembrolizumab combination |
| Designation | Breakthrough Therapy Designation (CDE/NMPA) |
| Indication | First‑line NSCLC (PD‑L1 ≥1%, EGFR‑negative, ALK‑negative) |
| Trial | Phase 3 OptiTROPLung05 |
| Primary Endpoint | Progression‑free survival (PFS) – statistically significant improvement |
| Secondary Endpoint | Overall survival (OS) – positive trend observed |
| Significance | First Phase 3 immunotherapy + ADC combo to meet primary endpoint in 1L NSCLC |
Phase 3 OptiTROPLung05 Trial
Design: Multicenter, randomized study evaluating sac‑TMT + pembrolizumab vs. pembrolizumab alone in PD‑L1‑positive NSCLC.
Results:
- PFS: Statistically significant and clinically meaningful improvement
- OS: Positive trend favoring combination arm
- Safety: Manageable toxicity profile consistent with individual agents
This marks the first time a TROP2 ADC + immunotherapy combination has demonstrated superiority in first‑line NSCLC, positioning sac‑TMT as a potential new standard of care.
Regulatory & Commercial Status in China
Already Approved/Marketed:
- EGFR‑mutant NSCLC (post‑EGFR‑TKI + platinum chemotherapy) – NRDL included
- Unresectable locally advanced/metastatic TNBC (≥2 prior systemic therapies) – NRDL included
- EGFR‑mutant NSCLC (post‑EGFR‑TKI) – Market approved
Global Licensing: In May 2022, Kelun‑Biotech licensed exclusive ex‑Greater China rights to MSD for sac‑TMT development and commercialization.
Manufacturing: Kelun retains Greater China manufacturing rights with capacity for 200+ kg/year at its Chengdu facility.
Market Opportunity: First‑Line NSCLC in China
Disease Burden:
- NSCLC Incidence: ~800,000 new cases annually in China
- PD‑L1‑Positive (≥1%): ~55‑60% of patients → ~440,000 eligible
- Target Population: First‑line setting represents largest opportunity (vs. later lines)
Market Size:
- China NSCLC Market: ¥45 billion (2025), growing at 12% CAGR
- ADC + IO Segment: ¥8‑10 billion potential by 2030
- Sac‑TMT Projected Peak Sales: ¥6‑8 billion (US$840M‑1.1B) in NSCLC alone
Competitive Landscape:
- TROP2 ADCs: Datopotamab deruxtecan (AZ/Daiichi) – Phase 3 ongoing
- Sac‑TMT Advantage: First to demonstrate Phase 3 success in 1L NSCLC; 9‑12 month head start
Financial Implications & Deal Economics
MSD Partnership:
- Upfront: USD 100 million (received 2022)
- Milestones: Up to USD 1.5 billion (development + commercial)
- Royalties: Mid‑teens to high‑teens on ex‑China sales
China Economics: Kelun retains 100% of Greater China revenue, projected ¥20 billion+ peak across all indications.
Stock Impact: BTD designation derisks regulatory pathway and could trigger MSD milestone payments upon NDA filing.
Forward‑Looking Statements
This brief contains forward‑looking statements regarding sac‑TMT’s clinical development, regulatory approvals, market penetration, and revenue projections. Actual results may differ materially due to competitive dynamics, regulatory review timelines, and market adoption rates.-Fineline Info & Tech