Tam-Peli extended median OS to 13.3 months in relapsed SCLC, against 9.4 months with topotecan

Median overall survival of 13.3 months against 9.4 with topotecan

The trial met its primary endpoint. Median overall survival was 13.3 months in the Tam-Peli group and 9.4 months in the topotecan group, a stratified hazard ratio of 0.46 with a 95% confidence interval of 0.35 to 0.62 and a p value below 0.0001. Roche states the result as a 54% reduction in the risk of death.

The figure rests on 451 patients enrolled at 85 study sites in China, all of whom had progressed after one prior line of platinum-based chemotherapy given with or without a PD-L1 inhibitor. Roche describes the comparator as standard-of-care topotecan. The analysis is interim, and the release gives neither the data cut-off date, nor the duration of follow-up, nor the number of deaths on which the hazard ratio was calculated. Without those, the maturity of the survival curve cannot be judged from the announcement.

Progression-free survival of 7.4 months, and responses in 59.1% against 9.7%

Median progression-free survival, assessed by investigators, was 7.4 months with Tam-Peli and 2.8 months with topotecan, giving a hazard ratio of 0.29 (95% CI 0.23 to 0.37, p<0.0001). The confirmed objective response rate was 59.1% against 9.7%, also at p<0.0001.

The announcement does not carry how long those responses lasted. Duration of response, disease control rate and time to response are all listed among the trial’s secondary endpoints, and none of them is reported with a figure. A response rate reported without a duration beside it records how many tumours shrank and leaves the reader without the interval over which that shrinkage held.

Roche reports that the survival and progression-free survival results held across prespecified subgroups, including age, chemotherapy-free interval below or above 90 days, and the presence of liver or brain metastases at baseline. Patients relapsing within 90 days of platinum are conventionally the harder group to treat, so consistency across that division carries more information than the subgroup list as a whole. No subgroup figures are given.

Intracranial progression-free survival of 6.1 months in patients with baseline brain metastases

Among patients who entered the trial with brain metastases, median intracranial progression-free survival was 6.1 months with Tam-Peli and 4.2 months with topotecan, an unstratified hazard ratio of 0.43 (95% CI 0.27 to 0.68). The intracranial response rate was 32.4% against 2.9%.

Central nervous system involvement is common in small-cell lung cancer and it shapes how a relapse is managed, so the intracranial figures are worth reading apart from the overall result. Two limits apply to them. The hazard ratio is unstratified, and the release reports neither the number of patients in this subgroup nor whether their brain disease had been irradiated before entry.

Grade 3 or higher treatment-related events in 46.4% against 74.7%

Treatment-related adverse events of grade 3 or higher occurred in 46.4% of patients receiving Tam-Peli and 74.7% of those receiving topotecan. Serious treatment-related events occurred in 25.9% against 36.4%. On both measures the experimental arm recorded the lower rate.

Interstitial lung disease runs the other way. Treatment-emergent interstitial lung disease or pneumonitis of any grade was reported in 4.9% of the Tam-Peli group against 1.4% of the topotecan group. Grade 3 events were reported in 0.9% of each group, and no grade 4 or grade 5 events were reported in either. Pulmonary toxicity is a recognised problem for antibody-drug conjugates carrying topoisomerase 1 inhibitor payloads, and the release gives the all-grade rates without the time to onset or the management required.

“These data demonstrate clinically meaningful survival and response rate improvements in an aggressive and hard-to-treat disease, supporting our plans to initiate global phase III trials quickly.”Levi Garraway, Roche’s Chief Medical Officer and Head of Global Product Development

A trial conducted entirely in China, and a second positive phase III for the molecule

Every one of the 451 patients was enrolled in China. Whether the result transfers to populations treated elsewhere is the question this trial was not designed to answer, and Roche states that it plans to initiate global phase III trials rapidly. The Center of Drug Evaluation of China’s National Medical Products Administration has accepted the New Drug Application for filing.

TAISHAN-302 is the second positive phase III readout for the molecule, following TAISHAN-301 in nasopharyngeal carcinoma. Tam-Peli targets B7-H3, a protein expressed across solid tumours and their microenvironment with limited expression in healthy tissue, and it is built on MediLink’s TMALIN linker platform with a topoisomerase 1 inhibitor payload at a drug-to-antibody ratio of 8. Under an exclusive licensing agreement signed in January 2026, Roche holds development and commercialisation rights outside mainland China, Hong Kong and Macau. The agent holds Breakthrough Therapy Designations for relapsed small-cell lung cancer from both the FDA and the China CDE.