Results from the Phase III TAISHAN-302 trial, presented at the International Association for the Study of Lung Cancer’s 2026 World Conference on Lung Cancer, showed that tambotatug pelitecan (Tam-Peli, YL201), an antibody-drug conjugate (ADC) targeting a protein called B7-H3, significantly improved survival compared with topotecan, the long-standing second-line chemotherapy, in patients with relapsed small-cell lung cancer (SCLC). The presenting organization, IASLC, is a neutral scientific association rather than the drug’s developer, and its release does not name the companies behind Tam-Peli or say which public company holds commercial rights to it; that context is added here.

The Gap This Trial Targeted

Small-cell lung cancer is an aggressive form of lung cancer that typically responds well to initial chemotherapy and immunotherapy but relapses in most patients, often within months, at which point treatment options have historically been limited and outcomes poor. Topotecan has been the standard second-line option for decades, but its survival benefit in this setting has long been considered modest, which is the specific gap TAISHAN-302 was designed to test whether Tam-Peli could close.

What the Trial Found

The randomized, open-label trial enrolled 451 patients with SCLC that had relapsed after first-line treatment, assigning 225 to Tam-Peli and 226 to topotecan. As of a May 2026 data cutoff, after a median follow-up of 9.4 months, median overall survival was 13.3 months with Tam-Peli versus 9.4 months with topotecan, a 54% reduction in the risk of death (hazard ratio 0.46; 95% CI 0.35 to 0.62; p<0.0001). Progression-free survival was also substantially better, a median of 7.4 months versus 2.8 months, a 71% reduction in the risk of progression or death (hazard ratio 0.29; 95% CI 0.23 to 0.37; p<0.0001), and the objective response rate was 59.1% with Tam-Peli compared with 9.7% with topotecan. The benefit held up across prespecified subgroups, including patients with brain or liver metastases.

Safety Profile

On safety, grade 3 or higher treatment-related side effects occurred less often with Tam-Peli (46.4%) than with topotecan (74.7%), and there were no treatment-related deaths in the Tam-Peli group. A specific concern for this drug class, lung inflammation known as interstitial lung disease or pneumonitis, occurred in 4.9% of Tam-Peli patients versus 1.4% on topotecan, though severe (grade 3) cases were rare and similar between the two groups, at under 1% each, with no grade 4 or 5 cases in either arm.

How Tam-Peli Works

Tam-Peli works by attaching a chemotherapy payload, a topoisomerase inhibitor called camptothecin, to an antibody that targets B7-H3, a protein overexpressed on many small-cell lung cancer cells, using a linker Tam-Peli’s developer describes as activated specifically within the tumor environment rather than throughout the body, intended to concentrate the drug’s effect on cancer cells.

Who Actually Owns This Drug

The drug is developed by MediLink Therapeutics, a private Chinese biotech, on its proprietary TMALIN platform. In January 2026, MediLink licensed exclusive worldwide rights to Tam-Peli, excluding mainland China, Hong Kong, and Macau, to Roche (SIX: RO, ROG; OTCQX: RHHBY), in a deal that included $570 million in upfront and near-term milestone payments, additional undisclosed development and commercial milestones, and tiered royalties on sales outside China. It was Roche’s second major deal with MediLink, following a roughly $1 billion agreement in 2024 for a different ADC targeting c-Met. Tam-Peli has already received FDA Breakthrough Therapy Designation for SCLC and three separate FDA Orphan Drug Designations, for SCLC, nasopharyngeal carcinoma, and esophageal squamous cell carcinoma.

A Competitive, Not Risk-Free, Target

B7-H3 is a competitive target right now, and not without risk for rivals. GSK has advanced a B7-H3 ADC developed with China’s Hansoh Pharma into Phase 3 trials, while a separate B7-H3 ADC being developed by Daiichi Sankyo and Merck, ifinatamab deruxtecan, had its Phase 3 lung cancer trial placed on clinical hold. That contrast, one rival program advancing while another hits a safety-related pause, is relevant context for how Tam-Peli’s data lands competitively, though it says nothing definitive about any of the individual drugs’ ultimate prospects. Separately, Tam-Peli is also in Phase III testing in China for nasopharyngeal carcinoma, a different trial called TAISHAN-301, which reported a positive interim result in May 2026 that MediLink described as the first positive Phase 3 result for any B7-H3-targeted ADC worldwide.

What’s Next

Professor Li Zhang of Sun Yat-sen University Cancer Center, the trial’s presenter, said the results support Tam-Peli as a potential new standard of care for second-line SCLC and could reshape treatment for the disease; that is the investigator’s own characterization of the data’s clinical significance rather than a regulatory or consensus determination, and Tam-Peli has not yet been approved for this use anywhere. This article covers clinical trial results presented at a medical conference and is not medical or investment advice; patients should discuss treatment options with a qualified healthcare professional.

Sources

International Association for the Study of Lung Cancer: Phase III TAISHAN-302 Trial Shows Tam-Peli Significantly Improves Survival in Relapsed Small-Cell Lung Cancer, PRNewswire, September 13, 2026.

European Biotechnology Magazine: Second time around: Roche’s return to MediLink underlines the value of the first deal, cited for background on the Roche-MediLink licensing deal and competitive landscape.

MediLink Therapeutics: MediLink Therapeutics Announces B7-H3 ADC YL201 Met Primary Endpoint in TAISHAN-301, cited for background on the separate TAISHAN-301 trial and FDA designations.

Editorial Disclosure

This article is based on a press release issued by the International Association for the Study of Lung Cancer on September 13, 2026, distributed via PRNewswire, describing results presented at the 2026 World Conference on Lung Cancer. Background on the drug’s corporate ownership, licensing terms, and competitive landscape, none of which was included in the IASLC release, was drawn from independent trade press and MediLink Therapeutics’ own announcements, cited above. MediLink Therapeutics is a privately held company; Roche, which holds ex-China commercial rights to the drug, trades on the SIX Swiss Exchange under the tickers RO and ROG and over the counter in the U.S. under the ticker RHHBY. BioTech Stocks Daily was not compensated for this coverage. Tam-Peli has not been approved for this indication by any regulatory authority. This article is for informational and educational purposes only and is not medical advice. Consult a qualified healthcare professional for medical guidance. See our full DISCLAIMER.