Tambotatug pelitecan vs topotecan in relapsed small-cell lung cancer: hazard ratio 0.46

Design

Phase 3, open-label, randomised, interim analysis

Population

451 patients with SCLC progressing after platinum-based therapy

Primary outcome

Overall survival

Effect

13.3 vs 9.4 months; HR 0.46 (95% CI 0.35 to 0.62)

TAISHAN-302 was a phase 3, open-label randomised trial in China. It assigned 451 patients whose small-cell lung cancer had progressed after first-line platinum to tambotatug pelitecan, an antibody-drug conjugate that targets B7-H3, or to topotecan. This report is a prespecified interim analysis.

Median overall survival was 13.3 months against 9.4 months (hazard ratio 0.46, 95% CI 0.35 to 0.62). Progression-free survival was 7.4 against 2.8 months (HR 0.29), and confirmed responses 59.1% against 9.7%. Grade 3 or higher adverse events were less common with the conjugate (55.4% vs 77.9%).

Topotecan has long been a weak second-line option in this disease, and this is a large survival gain over it. The caveats are an interim analysis, an open-label design for investigator-assessed endpoints, and a single-country population. The drug is not approved by the FDA, EMA or CDSCO on the basis of this report. Its main message for now is to consider trial referral for relapsed disease.

• Tambotatug pelitecan is investigational and not available outside trials.
• Overall survival improved by about 4 months against topotecan at interim analysis.
• Serious adverse events were less frequent than with topotecan.
• Consider trial referral for patients with relapsed small-cell lung cancer.
• Results apply to patients fit enough for the trial after first-line platinum.

Why it matters

Second-line small-cell lung cancer has had few gains in decades, and this is a survival benefit, not just response.

Don't overread it

An interim analysis of an open-label trial in one country; longer follow-up and regulatory review are still to come.

The statistics, in plain English

A hazard ratio of 0.46 means the risk of death at any point was roughly halved compared with topotecan. The upper limit of 0.62 still shows a large effect, so the benefit is unlikely to be chance. Interim analyses can overestimate effects, so the final figure may be smaller.

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