Tambotatug Pelitecan Significantly Improves Survival Over Topotecan in Patients With Relapsed Small Cell Lung Cancer
Clinical Summary:
- Design/Population: The phase 3 TAISHAN-302 trial compared tambotatug pelitecan, a B7-H3–directed antibody-drug conjugate, with topotecan in patients with small cell lung cancer (SCLC) who relapsed following first-line treatment.
- Key Outcomes: Tambotatug pelitecan significantly improved overall survival, reducing the risk of death by 54% compared with topotecan. The agent also significantly improved progression-free survival and objective response, with survival benefit observed across prespecified subgroups, including patients with brain or liver metastases and those with a shorter chemotherapy-free interval.
- Clinical Relevance: Results demonstrated that tambotatug pelitecan showed broad efficacy and favorable tolerability compared with an established second-line therapy, supporting its potential to become a new second-line treatment option for patients with relapsed SCLC.
Results from the phase 3 TAISHAN-302 trial demonstrated that tambotatug pelitecan significantly improved overall survival (OS) compared with topotecan as second-line treatment for patients with relapsed small cell lung cancer (SCLC).
These results were presented in a plenary session at the World Conference on Lung Cancer by Li Zhang, MD, Sun Yat-Sen University Cancer Center, Guangzhou, China.
In this trial, 451 patients were randomized 1:1 to receive either 2 mg/kg of tambotatug pelitecan intravenously on day 1 of each 3-week cycle, up to a maximum dose of 200 mg (n = 225), or topotecan per label (n = 226) until disease progression or unacceptable toxicity.
Patients were stratified according to limited-or extensive-stage disease, presence or absence of brain metastases, and chemotherapy-free interval of less than 90 days or at least 90 days. The primary end point was OS. Key secondary end points included progression-free survival (PFS), objective response rate (ORR), and safety.
At a median follow-up of 9.4 months, median OS was 13.3 months in the tambotatug pelitecan arm and 9.4 months in the topotecan arm (hazard ratio [HR], 0.46; 95% confidence interval [CI], 0.35 to 0.62; P < .0001), meeting the study’s primary end point.
The OS benefit was consistent across prespecified subgroups, including patients with brain metastases, liver metastases, and a chemotherapy-free interval of less than 90 days.
Median PFS was 7.4 months in the tambotatug pelitecan arm and 2.8 months in the topotecan arm, corresponding to a 71% reduction in the risk of disease progression or death (HR, 0.29; 95% CI, 0.23 to 0.37; P < .0001).
ORR was 59.1% in the tambotatug pelitecan arm and 9.7% in the topotecan arm (P < .0001).
Grade ≥3 treatment-related adverse events occurred in 46.4% of patients receiving tambotatug pelitecan and 74.7% of patients receiving topotecan. No treatment-related deaths were reprted in the tambotatug pelitecan arm.
Treatment-emergent interstitial lung disease (ILD)/pneumonitis occurred in 4.9% of patients receiving tambotatug pelitecan and 1.4% of patients receiving topotecan. Grade 3 ILD/pneumonitis occurred in 0.9% of patients in each arm. No grade ≥3 ILD/pneumonitis events were reported.
TAISHAN-302 is the first phase 3 trial of an antibody-drug conjugate to demonstrate statistically significant improvements in OS, PFS, and ORR compared with topotecan in relapsed SCLC. The magnitude of survival benefit across clinically relevant subgroups, together with the response and safety findings, supports tambotatug pelitecan as a potential new second-line treatment option.
Source:
Zhang L, Zhao Y, Liu H, et al. Tam-Peli, an anti-B7-H3 antibody-drug conjugate, versus topotecan in relapsed SCLC: A randomized, open-label, phase 3 Study (TAISHAN-302). Presented at the World Conference on Lung Cancer; September 12-15, 2026. Seoul, South Korea. Abstract PL02.03.
