Chinese ADC Companies Showcase Breakthrough Clinical Data at ESMO 2025
Key Insights
Kelun-Biotech (search)'s TROP2 (search) ADC sacituzumab demonstrated statistically significant improvements in both progression-free survival and overall survival for second-line EGFR (search)-mutant NSCLC (search) patients, becoming the world's first ADC to achieve dual benefits in this indication.
Alphamab Oncology (search)'s HER2 (search) bispecific antibody KN026 achieved a 55.8% objective response rate in HER2-positive gastric cancer (search), more than five times higher than the control group, with the potential to rewrite treatment guidelines.
Both companies' clinical successes at ESMO 2025 highlight the maturation of China's innovative drug development capabilities and the shift from single-product focus to technology platform-driven innovation.
Chinese pharmaceutical companies made a significant impact at the 2025 European Society for Medical Oncology (ESMO) conference, with breakthrough clinical data from antibody-drug conjugates (ADCs) and bispecific antibodies demonstrating the growing sophistication of China's innovative drug development capabilities.
Kelun-Biotech's TROP2 ADC Achieves Historic Breakthrough
Kelun-Biotech (search)'s sacituzumab, a TROP2 (search) ADC, delivered landmark results in the OptiTROP-Lung04 Phase III study for second-line treatment of EGFR (search)-mutant non-small cell lung cancer (NSCLC (search)). The study, which was showcased as a major oral presentation at the Presidential Symposium, evaluated sacituzumab monotherapy compared to pemetrexed combined with platinum-based chemotherapy in patients who had failed EGFR-TKI treatment.
The results showed that sacituzumab achieved statistically and clinically significant improvements in both progression-free survival (PFS) and overall survival (OS) compared to standard chemotherapy. This makes sacituzumab the world's first ADC drug to achieve dual benefits in PFS and OS for second-line EGFR (search)-mutant NSCLC (search) patients, filling a critical long-standing gap in this therapeutic area.
The significance of these results is amplified by the current regulatory environment, where the FDA's requirements for OS data are becoming increasingly stringent. Existing treatments for second-line EGFR (search)-mutant NSCLC (search) have shown variable OS performance, with none achieving significant OS benefits compared to standard chemotherapy.
Beyond lung cancer, sacituzumab also demonstrated promising results in breast cancer (search) through the randomized, multicenter Phase III OptiTROP-Breast 02 study, which evaluated its efficacy as a second-line or higher treatment for HR+/HER2 (search)- breast cancer. This study was also selected as a Late-Breaking Abstract (LBA) and presented orally at ESMO.
Alphamab Oncology's HER2 Platform Shows Exceptional Promise
Alphamab Oncology (search) presented breakthrough data for two core products: KN026, a HER2 (search) bispecific antibody, and JSKN003, a HER2 bispecific antibody-drug conjugate. The Phase III study data of KN026 for gastric cancer (search) was selected for oral presentation under the highest-profile "Late Breaking Abstract" category.
KN026 Transforms Gastric Cancer Treatment
The KC-WISE Phase III study targeting patients with HER2 (search)-positive locally advanced, recurrent, or metastatic gastric cancer (search) showed that KN026 achieved an objective response rate (ORR) of 55.8%, more than five times that of the control group (10.8%), with a disease control rate (DCR) reaching 80%. The performance of key indicators, with both PFS and OS hazard ratio values below 0.3, has been extremely rare in gastric cancer drug development over the past two decades.
KN026 significantly reduced the risk of disease progression or death by 75%, while lowering the risk of death by 71%. The drug also demonstrated higher safety and tolerability compared to existing treatments, allowing patients to undergo longer treatment periods.
Based on these results, the marketing application for KN026 in HER2 (search)-positive gastric cancer (search) was accepted by the National Medical Products Administration in September 2025.
JSKN003 Demonstrates Broad-Spectrum Activity
JSKN003 showed significant efficacy across multiple tumor types, demonstrating "tumor-agnostic and HER2 (search) expression-independent" characteristics. In primary platinum-resistant ovarian cancer (search), JSKN003 monotherapy achieved an ORR of 32.0% across patients with different HER2 expression levels, including those with IHC 0 expression.
In HER2 (search)-positive metastatic colorectal cancer (search) patients who had failed multiple lines of treatment, JSKN003 achieved a confirmed ORR of 68.8%, a disease control rate of 96.9%, and a median PFS of 11.04 months. The drug demonstrated outstanding safety, with a low incidence of grade 3 or higher treatment-related adverse events and no cases leading to treatment discontinuation or death.
Technology Platform Approach Drives Innovation
The success of both companies reflects a broader shift in oncology drug development from targeting individual "blockbuster targets" to building comprehensive "technology platforms." This paradigm change emphasizes the development of replicable, iterative platform-based innovation capabilities rather than relying on serendipitous discoveries.
Kelun-Biotech (search)'s success is built on its self-developed OptiDC technology platform, which enables comprehensive optimization of drug structure and molecular design, including antibody selection, linker stability, and precise control of payload release. This platform has enabled the company to launch ADC products targeting mature targets such as TROP2 (search), HER2 (search), and CLDN18.2 (search) with excellent clinical data across various solid tumors.
Alphamab Oncology (search) has developed multiple proprietary technology platforms, including a glycan site-specific conjugation platform, linker-payload platform, dual-payload conjugation platform, and bispecific antibody platform. The company's CRIB bispecific antibody platform successfully incubated KN026, whose unique "dual-epitope" binding mechanism generates synergistic effects surpassing traditional monoclonal antibodies.
Market Response and Future Outlook
The market responded positively to these developments, with Alphamab Oncology (search)'s stock price surging over 11% on the day of the ESMO conference. The company's revenue reached RMB 319 million in the first half of 2025, representing an 84% year-on-year increase, with net profit of RMB 21.58 million.
Multiple brokerage firms have expressed optimism about both companies' prospects. Projections suggest that KN026's peak sales could exceed RMB 6-7 billion, while JSKN003's peak sales are projected to reach RMB 3-4 billion. The risk-adjusted revenue from Alphamab's three core products is expected to peak by 2031 at approximately RMB 1.122 billion.
The success of these Chinese companies at ESMO 2025 represents a significant milestone in the evolution of China's pharmaceutical industry from imitation to innovation, demonstrating that Chinese companies can now compete at the highest levels of global drug development with platform-driven approaches that promise sustained innovation capabilities.