Roche notches ph. 3 lung cancer win but trails GSK on survival

MediLink has reported phase 3 results on a Roche-partnered antibody-drug conjugate (ADC). The small cell lung cancer (SCLC) trial hit its primary endpoint, although the B7-H3-directed ADC’s median overall survival (OS) fell short of the bar set by GSK’s rival asset.

Roche and GSK are advancing in the slipstream of Merck & Co. and Daiichi Sankyo, which have filed for FDA approval of their B7-H3 ADC based on a global phase 2 study that reported a median OS of 12 months in second-line SCLC. On Saturday, GSK’s partner Hansoh Pharma linked its rival B7-H3 ADC to a median OS of 18.5 months in a phase 3 trial of Chinese patients with relapsed SCLC.

Cross-trial comparisons can be unreliable, especially when analyzing trials performed in different parts of the world. But the available data put Roche’s tambotatug pelitecan (tam-peli) in the middle of the pack, with MediLink reporting a median OS of 13.3 months in a phase 3 trial it ran in China.

The median OS on tam-peli, also called YL201, was significantly longer than the 9.4 months achieved by the standard-of-care chemotherapy drug topotecan. Hansoh linked topotecan to a similar median OS in the control arm of its study.

With multiple B7-H3 ADCs in development, and Amgen’s DLL3xCD3 T-cell engager Imdelltra approved in second-line SCLC, the companies may need to differentiate their drug candidates to win market share. The search for an edge over the competition will extend to safety and tolerability data, where the risk of interstitial lung disease (ILD) is a concern. 

MediLink’s ILD data compare favorably to the competition, with 0.9% of patients on tam-peli having grade 3 adverse events and no participants experiencing more severe side effects. The rate of grade 3 adverse ILD events on the GSK-Hansoh and Merck-Daiichi ADCs was 3.9% and 4.4%, respectively. Two patients died after treatment-related ILD/pneumonitis events in the trial of the Merck-Daiichi ADC. 

The ILD data contributed to Roche’s conclusion that tam-peli showed a favorable and manageable safety profile. The rate of grade 3 or worse treatment-related adverse events on the ADC—46.4%—was lower than on topotecan. In Hansoh’s trial, 60.9% of patients had grade 3 or worse treatment-related adverse events, while Merck and Daiichi reported a 36.5% rate in their phase 2 study.  

MediLink reported a phase 3 win for tam-peli in another indication, nasopharyngeal carcinoma, in May. Buoyed by the results, Roche plans to start a global phase 3 program “quickly,” Levi Garraway, M.D., Ph.D., chief medical officer at the Swiss drugmaker, said in a statement. 

Roche secured ex-China rights to the ADC in January through a deal worth $570 million in near-term payments. The agreement gave the company another angle of attack on SCLC. Last year, the FDA approved Roche’s checkpoint inhibitor Tecentriq and Jazz Pharmaceuticals’ Zepzelca as a first-line maintenance treatment in SCLC. Roche named (PDF) SCLC as a driver of Tecentriq growth in the first half of 2026.