GSK and Roche Chinese ADC bets deliver positive phase 3 data in SCLC
Two B7-H3-targeted antibody-drug conjugates licensed from Chinese biotechs have now delivered positive phase 3 survival data in relapsed small-cell lung cancer, strengthening the oncology bets GSK and Roche made in China.
Why it matters: For GSK and Roche, the results give them both late-stage contenders in small-cell lung cancer (SCLC). In the bigger picture, Western drugmakers have looked more and more to Chinese biotechs to fill their pipelines. Some of those bets are now delivering late-stage results.
By the numbers: Roche reported that Tam-Peli cut the risk of death by 54% versus topotecan (chemotherapy) in a 451-patient phase 3 trial conducted in China. Median overall survival was 13.3 months versus 9.4 months, while median progression-free survival was 7.4 versus 2.8 months and the response rate was 59.1% versus 9.7%.
- Days earlier, Hansoh Pharma reported similar results for GSK-partnered risvutatug rezetecan, or ris-rez, in its 461-patient phase 3. Median overall survival was 18.5 months versus 10.3 months with topotecan, corresponding to the same 54% reduction in the risk of death. Median progression-free survival was 7.2 versus 3.0 months, and the response rate was 58.3% versus 12.6%.
Zoom in: Both drugs are ADCs directed at B7-H3, but they don’t use the same technology. Ris-rez couples the antibody to a topoisomerase I inhibitor. Tam-Peli uses MediLink’s TMALIN platform, which can release a camptothecin-based payload inside the cancer cell and in the tumor microenvironment.
Backstory: GSK licensed ris-rez from Hansoh in 2023, paying $185 million up front for rights outside China, Hong Kong, Macau, and Taiwan. At the time, the asset was still in phase 1 and 2 testing.
- Roche made its bet more recently, licensing Tam-Peli from MediLink in January 2026. MediLink received $570 million upfront, with Roche also gaining rights outside China, Hong Kong and Macau.
The competition: Daiichi Sankyo and MSD’s B7-H3 ADC ifinatamab deruxtecan is further ahead. The FDA granted it priority review in April for previously treated extensive-stage SCLC, with a decision due in October.
- Amgen’s Imdelltra offers another benchmark in the same post-platinum setting, although it is a DLL3-targeted T-cell engager. In phase 3, Imdelltra extended median overall survival to 13.6 months versus 8.3 months with chemotherapy and is approved in the U.S. and, since July, in Europe.
What to watch: Both new B7-H3 phase 3 data were generated in China. GSK has already started a global phase 3 study of ris-rez in relapsed SCLC, while Roche says it plans to begin global phase 3 testing of Tam-Peli. The next challenge for both companies is to reproduce the Chinese trials’ benefits in the global trials to come.
