# Sacituzumab tirumotecan (sac-TMT) by Merck & Co.

Canonical page: https://technooptimist.io/biotech/sac-tmt
Frontier: [Biotech](https://technooptimist.io/biotech.md) · Field: Antibody drugs · Company: [Merck & Co.](https://technooptimist.io/companies/merck.md)
Stage: Pilot (3 of 5: Research → Proto → Pilot → Deploy → Scaling)
Updated: last update 2026-05-29, facts checked 2026-10-11
Goal: Make a TROP2 drug conjugate the chemotherapy replacement that pairs with Keytruda across lung, breast, endometrial and other cancers, giving Merck its next oncology backbone.
Status: First global phase 3 win (endometrial, May 2026); 17 phase 3 trials; several approvals in China.
Next milestone: Full TroFuse-005 data and global filings, target 2026

## Milestones

| Status | Milestone | Date | Slip |
| --- | --- | --- | --- |
| Done | Merck licenses rights outside Greater China from Kelun | May 2022 |   |
| Done | China: first approval (Kelun-Biotech) |   |   |
| Done | China: EGFR-mutant lung cancer, first TROP2 conjugate approved in lung | Mar 2025 |   |
| Done | TroFuse-005 (endometrial) meets survival and progression endpoints | 18 May 2026 |   |
| Current | Full TroFuse-005 data and global filings | 2026 |   |

## Upcoming events

- **2026**: Full TroFuse-005 data and global filings

## Most important updates

- **29 May 2026**: Sac-TMT plus Keytruda cuts lung cancer progression risk by 65% versus Keytruda alone in a China trial. At ASCO 2026, Kelun presented a China phase 3 in first-line lung cancer in which sac-TMT added to Keytruda cut the risk of progression or death by 65% compared with Keytruda alone after 10.5 months of follow-up. ([our story](https://technooptimist.io/stories/sac-tmt-plus-keytruda-cuts-lung-cancer-progression-risk-by-65-versus-e1b521d3.md) · [original source](https://www.biopharmadive.com/news/merck-asco-2026-sac-tmt-lung-cancer-results/821500/))
- **18 May 2026**: Merck's sac-TMT improves survival in TroFuse-005, its first positive global phase 3, in endometrial cancer. Merck said sac-TMT beat standard chemotherapy (doxorubicin or paclitaxel) on both overall survival and progression-free survival in women with advanced endometrial cancer that had progressed after platinum chemotherapy and immunotherapy. ([our story](https://technooptimist.io/stories/merck-s-sac-tmt-improves-survival-in-trofuse-005-its-first-positive-fffaed7a.md) · [original source](https://www.merck.com/?p=3690800))
- **10 Mar 2025**: China approves sac-TMT for EGFR-mutant lung cancer, the first TROP2 conjugate approved in lung cancer. Kelun-Biotech won Chinese approval for sac-TMT as second-line treatment of EGFR-mutant lung cancer, its second indication in China. ([our story](https://technooptimist.io/stories/china-approves-sac-tmt-for-egfr-mutant-lung-cancer-the-first-trop2-36f82d84.md) · [original source](https://filingreader.com/news-wire/shenzhen/2025-03-17/keluns-sac-tmt-lung-cancer-treatment-approved-in-china))

## Current obstacles

- **China data vs global trials**: The striking lung result came from a Kelun trial in China without a Keytruda-chemo control; global trials must confirm it.
- **Three TROP2 rivals**: Datroway and Gilead's Trodelvy target TROP2 too, and PD-1 x VEGF bispecifics compete for first-line lung.

## Physics limits

- **TROP2 is also on healthy tissue**: Skin and mucous membranes carry TROP2, so mouth sores, rash and blood-count drops come with the target and cap the dose.
- **Payload resistance**: All current TROP2 conjugates use topoisomerase I poisons; tumours that pump the drug out or repair the damage escape the whole class.

## How it works

### Target: TROP2 on the tumour surface

The antibody binds TROP2, a protein found on most epithelial cancers such as lung, breast and endometrial.

### Payload: Belotecan-derived poison

Carries a topoisomerase I inhibitor derived from belotecan that breaks DNA as cancer cells divide.

### Linker: Built to hold in blood

A bifunctional linker is designed to keep the payload attached in circulation and release it at the tumour.

### Combination: Partnered with Keytruda

Dying tumour cells may prime the immune system, so many trials add Keytruda instead of chemotherapy.

## Spec sheet

| Spec | Sacituzumab tirumotecan (sac-TMT) | Provenance |
| --- | --- | --- |
| Global phase 3 trials | 17 | reported |
| Patients in phase 3 program | 15,000+ | reported |
| TroFuse-005 patients | 776 | reported |
| Dose (TroFuse-005) | 4 mg/kg every 2 weeks | reported |
| China lung trial with Keytruda: PFS | 65% lower risk vs Keytruda alone | reported |

Provenance: reported = stated by the company; estimated = our estimate; sample = a sample figure.

## About Merck & Co.

US drugmaker (MSD outside North America) behind Keytruda. Its main bet on the next generation of cancer drugs is sac-TMT, a TROP2 antibody-drug conjugate licensed from China's Kelun-Biotech.

- Sac-TMT: 17 global phase 3 trials enrolling 15,000+ patients, 10 of them in women's cancers.
- First global phase 3 win (TroFuse-005, endometrial cancer) in May 2026, on both survival and progression.
- Licensed outside Greater China from Kelun-Biotech in May 2022.

- Headquarters: US
- Status: public
- Website: https://www.merck.com
- Partners, customers, investors: Kelun-Biotech (partner)

Company page: https://technooptimist.io/companies/merck.md

## Related programs

Everything in Biotech: https://technooptimist.io/biotech.md

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