By Fineline Cube 
Merck Sharp & Dohme Inc. (MSD, NYSE: MRK) announced that Winrevair (sotatercept for injection), the world’s first and only Activin Signaling Inhibitor (ASI), has been approved by China’s National Medical Products Administration (NMPA). The drug is indicated for adult patients with Pulmonary Arterial Hypertension (PAH, WHO Group 1) with WHO Functional Class (FC) II-III to improve exercise capacity and functional class.
Regulatory & Product Milestone
| Item | Detail |
|---|---|
| Product | Winrevair (sotatercept for injection) |
| Company | Merck Sharp & Dohme (MSD, NYSE: MRK) |
| Mechanism | Activin Signaling Inhibitor (ASI) |
| Status | NMPA approval (Priority Review granted) |
| Indication | PAH (WHO Group 1), FC II-III adults |
| Clinical Basis | Phase III STELLAR trial |
| Global Precedent | Approved by FDA (Mar 2024) and EMA (Aug 2024) |
Novel Mechanism of Action
ASI Targeting PAH Pathogenesis: Winrevair captures excess Activin A, restoring imbalanced signaling pathways:
- Inhibits aberrant cell proliferation in pulmonary vasculature
- Improves vascular structure and restores vessel patency
- Reduces pulmonary vascular resistance and right ventricular strain
This represents a paradigm shift from vasodilator‑centric therapies (PDE5 inhibitors, ERAs, prostacyclins) to disease‑modifying vascular remodeling.
China Market Access Pathway
Pre‑Approval Access:
- March 2025: Launched in Lecheng Pilot Zone (Hainan)
- December 2025: Fuwai Hospital (Chinese Academy of Medical Sciences) granted temporary import approval
- January 2026: Full NMPA approval enables nationwide commercialization
Reimbursement Landscape: Included in National Reimbursement Drug List (NRDL) since March 2023, ensuring broad patient access.
Market Opportunity in China
PAH Epidemiology:
- Prevalence: 50,000‑100,000 diagnosed patients (estimated)
- Incidence: 2‑3 per million annually
- Treatment Gap: <30% of eligible patients receive targeted therapy
- Market Size: China PAH drug market valued at ¥1.2 billion (US$170M) in 2025, growing at 18% CAGR
Winrevair Revenue Projection:
- 2026: ¥400‑500 million (partial year, NRDL‑driven volume)
- 2027: ¥900 million‑1.2 billion (full year penetration)
- 2028 Peak: ¥1.6‑2.0 billion (US$225‑280M) with 30‑35% market share
Competitive Landscape
| Drug | Company | Mechanism | China Status | Annual Cost (¥) |
|---|---|---|---|---|
| Winrevair | Merck | ASI (novel) | Approved | ¥180,000‑200,000 (pre‑discount) |
| Opsumit | Johnson & Johnson | ERA | Marketed | ¥120,000 |
| Adempas | Bayer | sGC stimulator | Marketed | ¥150,000 |
| Uptravi | Johnson & Johnson | Prostacyclin | Marketed | ¥200,000 |
| Generic PDE5i | Various | PDE5 inhibitor | Marketed | ¥20,000‑40,000 |
Differentiation: Winrevair’s novel mechanism offers potential disease modification vs. symptomatic relief, commanding premium pricing.
Commercial & Manufacturing Strategy
Distribution: Via MSD Pharma (China) Co., Ltd. utilizing specialty pharmacy network covering 800+ tertiary hospitals.
Pricing: Expected 50% discount to US pricing (US$190,000/year) to meet NRDL requirements, translating to ¥95,000‑110,000 annually.
Manufacturing: Global supply chain with dedicated China inventory; cold chain logistics for injectable biologic.
Forward-Looking Statements
This brief contains forward‑looking statements regarding Winrevair’s market penetration, revenue forecasts, and competitive positioning in China. Actual results may differ materially due to patient access dynamics, competitive responses, and NRDL pricing negotiations.-Fineline Info & Tech