Lepu Biopharma and AstraZeneca Announce Positive Phase III Results for CMG901 in Advanced Gastric Cancer
Key Insights
The CLARITY-Gastric01 Phase III trial of CMG901 (sonesitatug vedotin (search)/AZD0901) met its primary overall survival endpoint in third-line and later Claudin 18.2 (search)-positive gastric/GEJ cancer patients.
CMG901 demonstrated statistically significant and clinically meaningful improvement in overall survival compared to investigator's choice of standard therapies in both 3L+ and broader 2L+ populations.
The Claudin 18.2 (search)-targeting ADC showed a safety profile consistent with prior data and no new safety signals, with a non-significant trend toward improved progression-free survival.
Lepu Biopharma (search), in partnership with AstraZeneca, has announced positive top-line results from the global CLARITY-Gastric01 Phase III trial evaluating CMG901 (sonesitatug vedotin (search), also known as AZD0901), a Claudin 18.2 (search)-targeting antibody-drug conjugate (ADC), in patients with advanced or metastatic gastric and gastroesophageal junction (GEJ) cancers. The study met its primary endpoint, demonstrating a statistically significant and clinically meaningful improvement in overall survival (OS) compared to current standard therapies.
The randomized, open-label, sponsor-blinded trial was conducted across 175 centers in 19 countries, underscoring the broad global scope of the development program. CMG901 is being developed under a global exclusive out-license agreement between Lepu Biopharma (search) and AstraZeneca, with KYM Biosciences (search)—a joint venture between Lepu Biopharma (30%) and Keymed (search) (70%)—focused on the drug's development and commercialization.
Trial Design and Endpoints
The CLARITY-Gastric01 trial enrolled patients with advanced or metastatic gastric cancer (search), GEJ cancer, or esophageal adenocarcinoma (search) (EAC) whose tumors expressed Claudin 18.2 (search) on at least 25% of tumor cells. All participants had failed at least one prior systemic therapy. The study employed dual primary endpoints: overall survival in the third-line and later-line (3L+) setting, and progression-free survival (PFS) in the overall (2L+) population.
The trial successfully met the OS endpoint in the 3L+ treatment group. Additionally, a key secondary endpoint of OS in the broader 2L+ population also showed statistically significant and highly clinically meaningful improvement. However, while a trend toward improved PFS was observed in the 2L+ population, it did not reach statistical significance.
Safety Profile
CMG901 was well tolerated, with no new safety signals identified. The safety profile remained consistent with previously reported data for the ADC, which comprises a Claudin 18.2 (search)-specific antibody, a cleavable linker, and the toxic payload monomethyl auristatin E (search) (MMAE).
Regulatory Designations and Development Strategy
CMG901 holds the distinction of being the first Claudin 18.2 (search) ADC to receive IND approval in both China and the United States. It has been granted Breakthrough Therapy Designation from China's Center for Drug Evaluation (CDE) for Claudin 18.2-positive advanced gastric cancer (search), as well as Orphan Drug Designation and Fast Track Designation from the U.S. FDA for relapsed/refractory gastric cancer and gastroesophageal junction adenocarcinoma.
AstraZeneca is advancing multiple additional Phase II and III studies for CMG901 across gastric, pancreatic, and biliary tract cancers, including trials in first-line therapy and perioperative settings, reflecting a broad clinical development strategy.
Market Opportunity
The addressable patient population is substantial. Approximately 183,500 patients in the United States, European Union, China, and Japan are treated annually in the second-line and later setting for advanced or metastatic Claudin 18.2 (search)-positive, non-HER2-positive gastric and GEJ cancers. This represents a significant commercial opportunity should regulatory approvals and launches proceed.
Claudin 18.2 (search) is a tumor target highly expressed in gastric, pancreatic, and other solid tumors, positioning CMG901 as a potentially important therapeutic option across multiple gastrointestinal malignancies if ongoing studies yield favorable results.
Implications
The positive Phase III data represent a significant milestone for Lepu Biopharma (search) and its shareholders, supporting the potential for regulatory filings and future market approvals in major global markets. The results, combined with existing regulatory designations and the AstraZeneca partnership, enhance the likelihood of successful commercialization. However, as noted by the company, there is no guarantee that CMG901 will be successfully launched or commercialized, and regulatory and market risks remain.