Phase III TAISHAN-302 Trial Shows Tam-Peli Significantly Improves Survival in Relapsed Small-Cell Lung Cancer

(SEOUL, Republic of Korea — September 13th at 10:45 a.m. Korea Standard Time) —The phase III TAISHAN-302 trial found that tambotatug pelitecan (Tam-Peli, YL201), a novel anti-B7-H3 antibody-drug conjugate, significantly improved overall survival, progression-free survival, and objective response rate compared with topotecan in patients with relapsed small-cell lung cancer (SCLC). The findings were presented at the International Association for the Study of Lung Cancer (IASLC) 2026 World Conference on Lung Cancer (WCLC).

Relapsed SCLC remains a highly aggressive disease with limited effective treatment options and poor outcomes following first-line immunotherapy and platinum-based chemotherapy. Topotecan has long been a standard second-line treatment, but its survival benefit remains modest. TAISHAN-302 evaluated Tam-Peli as a second-line treatment for patients whose SCLC had relapsed after first-line therapy.

The randomized, open-label study enrolled 451 patients, with 225 assigned to Tam-Peli and 226 to topotecan. Patients receiving Tam-Peli were treated with 2.0 mg/kg intravenously on day 1 of each three-week cycle, with a maximum dose of 200 mg. Treatment continued until disease progression or unacceptable toxicity. The study's primary endpoint was overall survival, with progression-free survival and objective response rate as key secondary endpoints.

As of May 20, 2026, after a median follow-up of 9.4 months, median overall survival was 13.3 months with Tam-Peli compared with 9.4 months with topotecan. Tam-Peli reduced the risk of death by 54% (HR 0.46; 95% CI 0.35–0.62; p<0.0001). The survival benefit was consistent across prespecified subgroups, including patients with brain metastases, liver metastases and a chemotherapy-free interval of less than 90 days.

Tam-Peli also significantly improved progression-free survival. Median progression-free survival was 7.4 months with Tam-Peli versus 2.8 months with topotecan, representing a 71% reduction in the risk of disease progression or death (HR 0.29; 95% CI 0.23–0.37; p<0.0001). The objective response rate was 59.1% with Tam-Peli compared with 9.7% with topotecan (p<0.0001).

The safety profile of Tam-Peli was considered manageable and consistent with its known profile, with no new safety signals identified. Grade 3 or higher treatment-related adverse events occurred in 46.4% of patients receiving Tam-Peli compared with 74.7% receiving topotecan, and there were no treatment-related deaths in the Tam-Peli arm. Treatment-emergent interstitial lung disease or pneumonitis occurred in 4.9% of patients receiving Tam-Peli and 1.4% receiving topotecan; grade 3 events occurred in 0.9% of patients in each group, with no grade 4 or 5 events reported.

"TAISHAN-302 is among the first phase III studies of an antibody-drug conjugate to demonstrate statistically significant and clinically meaningful improvements in overall survival, progression-free survival and objective response rate compared with topotecan in relapsed small-cell lung cancer," said Professor Li Zhang of Sun Yat-sen University Cancer Center. "Together with a generally favorable and manageable safety profile, these results support Tam-Peli as a potential new standard-of-care option for second-line SCLC and may reshape the treatment landscape for this challenging disease."

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About the IASLC:
The International Association for the Study of Lung Cancer (IASLC) is the only global organization dedicated solely to the study of lung cancer and other thoracic malignancies. Founded in 1974, the association's membership includes more than 10,000 lung cancer specialists across all disciplines in over 100 countries, forming a global network working together to conquer lung and thoracic cancers worldwide. The association also publishes the Journal of Thoracic Oncology, the primary educational and informational publication for topics relevant to the prevention, detection, diagnosis, and treatment of all thoracic malignancies. Visit www.iaslc.org for more information.

About the WCLC:
The WCLC is the world's largest meeting dedicated to lung cancer and other thoracic malignancies, attracting nearly 7,000 researchers, physicians, and specialists from more than 100 countries. The goal is to increase awareness, collaboration and understanding of lung cancer, and to help participants implement the latest developments across the globe. The conference will cover a wide range of disciplines and unveil several research studies and clinical trial results. For more information, visit https://wclc.iaslc.org/.