Seoul – September 16, 2026 -- A phase III trial of tambotatug pelitecan (Tam-Peli, YL201), an anti-B7-H3 antibody-drug conjugate, cut the risk of death by 54% compared with standard-of-care topotecan in patients with relapsed small-cell lung cancer (SCLC), according to data presented at the IASLC 2026 World Conference on Lung Cancer.
Trial enrolled 451 patients across two treatment arms
The randomized, open-label TAISHAN-302 study assigned 225 patients to Tam-Peli, dosed at 2.0 mg/kg intravenously every three weeks up to a 200 mg cap, and 226 patients to topotecan. Treatment continued until disease progression or unacceptable toxicity, with overall survival as the primary endpoint.
Median survival extended by 3.9 months versus topotecan
As of the May 20, 2026 data cutoff, after a median follow-up of 9.4 months, median overall survival reached 13.3 months with Tam-Peli versus 9.4 months with topotecan (HR 0.46; 95% CI 0.35-0.62; p0.0001). The benefit held across prespecified subgroups, including patients with brain metastases, liver metastases and a chemotherapy-free interval under 90 days.
Progression-free survival nearly triples with new conjugate
Median progression-free survival was 7.4 months with Tam-Peli compared with 2.8 months with topotecan, a 71% reduction in risk of progression or death (HR 0.29; 95% CI 0.23-0.37; p0.0001). The objective response rate reached 59.1% with Tam-Peli against 9.7% with topotecan (p0.0001).
Safety data show fewer severe adverse events with Tam-Peli
Grade 3 or higher treatment-related adverse events occurred in 46.4% of Tam-Peli patients versus 74.7% of topotecan patients, with no treatment-related deaths in the Tam-Peli arm. Treatment-emergent interstitial lung disease or pneumonitis occurred in 4.9% of Tam-Peli patients and 1.4% of topotecan patients; grade 3 events were reported in 0.9% of each group, with no grade 4 or 5 cases.
Professor Li Zhang of Sun Yat-sen University Cancer Center in Guangzhou said the results support Tam-Peli as a potential new standard-of-care option for second-line SCLC treatment, calling the trial among the first phase III studies of an antibody-drug conjugate to show statistically significant survival gains over topotecan in this indication.