If a patient's lung cancer was once controlled with targeted therapy but scans later show that the tumor is growing again, the patient and family may most want to know: is there another treatment? Will it stabilize the tumor temporarily, or help the patient live longer?
For another patient just beginning treatment, the question may be different: is there a chance to start with a more effective regimen whose burden is manageable? The same new drug can contribute to answering these questions, but each answer needs its own supporting study.
In October 2026, at the European Society for Medical Oncology annual meeting in Madrid, known as ESMO, three phase 3 studies of sacituzumab tirumotecan, or sac-TMT, developed by Kelun-Biotech, reported results worth reading together. They covered two different settings in lung cancer and previously treated endometrial cancer. [1–3]
Together, these results outline the drug's therapeutic potential. They also remind us that understanding good news about a new medicine begins with asking which patient's question, at which treatment stage, it answers.
Why can one ADC be used in different cancers?
sac-TMT is an antibody–drug conjugate, abbreviated ADC. These drugs link an antibody that recognizes a particular target to a cytotoxic drug, with the aim of delivering the drug into tumor cells with the corresponding characteristics.
This drug's target is TROP2, which can be expressed in a range of solid tumors. That is why researchers explore the same drug in different cancers. But sharing a target does not guarantee that different cancers respond in the same way. The disease itself, prior treatments and combination regimens can all change the outcome. [2][3]
An ADC still carries a cytotoxic drug. A design for targeted delivery does not guarantee that normal tissues will be entirely unaffected. Both efficacy and adverse effects belong in our reading of a study.
The first answer: can patients live longer after resistance to targeted therapy?
OptiTROP-Lung04 involved patients with EGFR-mutated advanced nonsquamous non-small-cell lung cancer whose disease had progressed after EGFR-targeted therapy. It compared sac-TMT monotherapy with platinum-based doublet chemotherapy.
The prespecified final overall survival analysis announced on October 25 showed median overall survival of 25.9 months with sac-TMT and 17.4 months in the control group. The hazard ratio for death was 0.69, corresponding to a 31% reduction in the relative hazard of death during study follow-up. [1]
“Overall survival” is the time from a study-defined starting point until death. In this randomized trial, it was measured from randomization, rather than the patient's initial diagnosis. The 25.9 and 17.4 months are medians of the groups' survival distributions. They cannot predict an individual patient's remaining life, and do not mean that everyone gains an additional 8.5 months.
This update matters because follow-up is more mature. Earlier results had already shown that the drug could delay progression; the study now provides further evidence of an overall survival benefit. For patients facing resistance, that makes the significance of a treatment option more concrete.
The second answer: can it be used earlier in treatment?
OptiTROP-Lung06 asked a different question. It enrolled 455 patients with PD-L1-negative, EGFR- and ALK-negative advanced nonsquamous non-small-cell lung cancer, comparing first-line sac-TMT plus pembrolizumab with platinum-based doublet chemotherapy plus pembrolizumab. “First-line” here means the first systemic regimen started for advanced disease. [2]
Median progression-free survival was 15.0 months versus 5.7 months, with a hazard ratio for progression or death of 0.49. The study showed a trend toward improved overall survival, but at this analysis neither group had reached median overall survival. Median follow-up was 9.7 months. [2]
Progression-free survival is often abbreviated PFS. It is usually measured from randomization to disease progression or death, whichever occurs first. It can reflect how long treatment controls the disease, but answers a different question from overall survival.
Delaying progression has value; showing longer life requires separate evidence. Delayed progression may mean changing regimens later and having more room to plan daily life. Whether it also brings better symptoms, quality of life or longer survival must be judged from the relevant study results.
Another change is worth noting in this trial: both groups retained immunotherapy, while the experimental group replaced the traditional chemotherapy component with an ADC. Further observation must show whether this approach maintains its advantage with longer follow-up and whether patients can manage its treatment burden.
This also explains why Lung04 and Lung06 are not two successive steps experienced by the same patients. Their populations, prior treatment and comparators differ. They provide evidence in two different treatment settings.
The third answer: can a global study show benefit in a different cancer?
The global phase 3 TroFuse-005 study, led by Merck, brought sac-TMT into advanced or recurrent endometrial cancer. It enrolled 776 patients previously treated with platinum-based chemotherapy and PD-1 or PD-L1 therapy, comparing the new drug with investigator's-choice chemotherapy.
Detailed results announced on October 26 showed median overall survival of 19.0 months versus 12.1 months, with a hazard ratio for death of 0.68. However, grade ≥3 treatment-related adverse events were also more frequent: 54.4% versus 41.4%. These higher-grade adverse effects need to be understood in terms of the specific events, their management and treatment continuation. [3]
As of this article's evidence cutoff, the U.S. FDA had accepted the application for this indication and granted priority review, with a target decision date of June 15, 2027. Priority review means a shorter target review period. Approval still depends on assessment of the complete evidence. [3]
For patients, a successful study and access to the medicine remain some distance apart. The countries in which a drug is approved, its indications, supply and payment arrangements all affect whether treatment can actually become part of everyday life. A positive global study is an important step along that path.
How should the three positive results be read together?
These studies can be understood as three increasingly clear findings. In one setting of resistant lung cancer, more mature follow-up supports an overall survival benefit. In another lung cancer population receiving first-line treatment, a large PFS advantage was observed while overall survival remains pending. In endometrial cancer, global phase 3 data also advanced U.S. regulatory review.
They expand our understanding of the same drug, but the applicability of each result is defined by the patients enrolled, treatment stage and comparator. After a drug works in a study, the next question is still whether it suits the particular patient in front of us, at this particular point in treatment.
This is why clinical research deserves continued follow-up. The story continues after data are announced: survival findings mature, experience in managing adverse effects accumulates, and treatment sequencing and real-world use bring new questions.
Ultimately, the three sets of results should serve a concrete purpose: when patients need to make their next treatment choice, they should have more reliable evidence and more possibilities worth serious consideration.
References
- Kelun-Biotech: Announcement of the final overall survival analysis of OptiTROP-Lung04, 2026-10-25.
- Kelun-Biotech: Announcement of OptiTROP-Lung06 results, 2026-10-25.
- Merck: Announcement of TroFuse-005 results and FDA priority review, 2026-10-26.
Evidence cutoff: October 27, 2026. This article is for public science education. Consult an oncologist about specific treatment.
This is Before the Conclusion.
What does a news item, a number or a seemingly good result really mean? Follow Before the Conclusion as we use medicine and science to understand the reasoning and tradeoffs behind the evidence, and keep asking questions.
Text and image usage statement
The text of this article is original work by Before the Conclusion. You are welcome to share a link to this webpage. Copying, reposting, republishing screenshots and commercial use are prohibited without permission. Any separately supplied accompanying illustrations are subject to the same restrictions and may not be used individually without permission. Image-production and source information is given in the relevant captions.