China-based MediLink Therapeutics presented Phase III data showing its B7-H3-targeted antibody-drug conjugate (ADC) tambotatug pelitecan (Tam-Peli) delivered a large survival advantage over topotecan in relapsed small-cell lung cancer (SCLC), strengthening the case for the drug as a potential new treatment option in a setting where effective therapies remain limited. The result also gives Roche, which licensed Tam-Peli outside Greater China earlier this year, a positive survival dataset for the asset and directly supports an NDA now under priority review in China.
Results from the TAISHAN-302 trial, presented at the International Association for the Study of Lung Cancer (IASLC) 2026 World Conference on Lung Cancer, showed Tam-Peli cut the risk of death by 54% compared with topotecan. The data were simultaneously published in The New England Journal of Medicine and represent the second positive Phase III readout for the ADC, following an earlier win in nasopharyngeal carcinoma.
In the TAISHAN-302 trial, 451 patients in China with SCLC who had progressed after one prior line of platinum-based chemotherapy, with or without a PD-L1 inhibitor, were randomized to Tam-Peli or topotecan. Median overall survival (OS) was 13.3 months with Tam-Peli versus 9.4 months with topotecan (stratified HR 0.46; 95% CI 0.35–0.62; p<0.0001). Median progression-free survival (PFS) was 7.4 versus 2.8 months (HR 0.29; 95% CI 0.23–0.37; p<0.0001), and confirmed objective response rate (ORR) was 59.1% versus 9.7%. Grade ≥3 treatment-related adverse events (TRAEs) occurred in 46.4% of Tam-Peli patients versus 74.7% on topotecan. Interstitial lung disease (ILD)/pneumonitis of any grade occurred in 4.9% of patients receiving Tam-Peli versus 1.4% with topotecan, though Grade 3 events were low and equal in both arms (0.9%), with no Grade 4 or 5 events reported.
Tam-Peli links a B7-H3-targeting monoclonal antibody to a topoisomerase 1 inhibitor payload via Suzhou-based MediLink Therapeutics' TMALIN platform, which uses a dual-release mechanism designed to deliver cytotoxic payload both intracellularly and extracellularly within the tumor microenvironment. B7-H3 is broadly expressed across solid tumors but minimally in normal tissue.
The trial data directly support a regulatory filing that China's National Medical Products Administration (NMPA) accepted in September 2026 for priority review. An earlier NMPA acceptance covered Tam-Peli in nasopharyngeal carcinoma in July 2026, based on Phase III TAISHAN-301 data showing the drug met its ORR co-primary endpoint. Roche, which licensed Tam-Peli from MediLink in January 2026 for all territories outside mainland China, Hong Kong, and Macau, said it plans to initiate global Phase III trials rapidly. MediLink said it received USD 570 million in upfront and near-term milestone payments under that agreement, with additional development, regulatory, and commercial milestones plus tiered royalties on ex-China net sales.