Stomach cancer: New survival data do not replace a Swiss approval
AstraZeneca reports a survival benefit for Sone-Ve in previously treated patients. A second primary endpoint was missed. For Switzerland, this so far means neither approval nor reimbursement.
An experimental drug against advanced stomach cancer has extended overall survival in a phase III trial. AstraZeneca published the results for sonesitatug vedotin, or Sone-Ve, on Sunday, 25 October 2026, at the European oncology congress ESMO in Madrid. Reuters also reports on the benefit – and on the fact that another important study endpoint was not met.
For patients in Switzerland, the news is therefore neither irrelevant nor a promise of a treatment that will soon be available. What matters are the disease situation studied, the balance of benefits and risks, and independent decisions on approval and reimbursement. A congress announcement does not answer these questions conclusively.
Ten instead of five months – in which group?
The CLARITY-Gastric01 study included 532 people with advanced tumours of the stomach or adjacent areas. A requirement was that at least 25 percent of the tumour cells carried the protein Claudin 18.2. All participants had already been treated. Sone-Ve belongs to the antibody-drug conjugates: an antibody is linked to an agent that damages cancer cells.
In patients from the third line of therapy onwards, meaning after at least two prior treatments, median overall survival was ten months according to the manufacturer, compared with five months on the comparator therapy chosen by the physician. Reuters confirms these figures. The corresponding ratio of death rates, the hazard ratio, was 0.47. The company describes this as a relative risk reduction of 53 percent.
The median is not an individual prognosis. It marks the point at which the estimated survival curve reaches half. The difference means neither that every person gains exactly five months, nor that 53 percent of those treated would be cured. For the personal conversation, existing therapies, tumour characteristics and state of health remain decisive.
The second endpoint limits the success message
In the overall study group from the second line of therapy onwards, AstraZeneca reports a median overall survival of 10.6 versus 6.4 months. This was an important secondary endpoint. The primary endpoint for overall survival, by contrast, referred to the more heavily pre-treated group from the third line onwards. These two analyses must not be conflated. The manufacturer's data are based on a planned interim analysis with a data cut-off of 31 May 2026. An interim analysis is not yet a final long-term observation.
The other primary endpoint, independently assessed survival without progression of the disease in the overall group, did not reach statistical significance according to the manufacturer. That does not cancel the observed survival benefit. But it prevents the presentation of a consistently positive result across all key study goals. Tolerability is likewise part of the assessment: even an effective drug can cause substantial side effects.
What Swissmedic has to review
For Swiss approval, Swissmedic assesses quality, safety and efficacy on the basis of comprehensive scientific documentation, according to its own description. It is not the headline, nor a single endpoint alone, that decides, but the submitted dossier. If approval is granted, the authority also approves the professional and patient information and defines the dispensing category.
The exact use is therefore also central. A study in pre-treated patients selected by means of a biomarker is not proof of efficacy for an unselected group or an earlier treatment time point. An approval decision would have to make clear for whom and under what conditions the preparation may be used. The study announcements reviewed here document no such Swiss decision.
Approval and reimbursement are two decisions
For regular inclusion in the list of pharmaceutical specialities, the Federal Office of Public Health requires Swissmedic approval as well as efficacy, appropriateness and cost-effectiveness. The Federal Drug Commission advises the FOPH on original preparations. The demonstrated medical benefit is therefore essential, but does not answer the price and reimbursement question on its own.
The procedures do not have to start strictly one after the other. The FOPH explains that companies can submit applications before or together with a positive Swissmedic preliminary decision. However, this does not imply a guaranteed waiting period for this medicine. Neither a concrete Swiss launch date nor a later price can be derived from general procedural goals.
For those affected, the practical consequence is: the new data are a reason for a precise conversation with the oncology treatment team, not for a self-directed change of therapy. Patients should ask about the matching tumour characteristic, the treatment line and documented access. Only when these levels fit together does a statistical study benefit become a realistic additional treatment option in Switzerland.
Sources
- AstraZeneca: CLARITY-Gastric01 results, 25 October 2026
- Swissmedic: Authorisations for human medicines
- FOPH: Application processes for medicines
- FOPH: Inclusion of new medicines in the list of pharmaceutical specialities
- National Cancer Institute: Median overall survival
- National Cancer Institute: Hazard ratio
- Reuters: Study results and missed endpoint, 25 October 2026
- Lead image: Rhoda Baer / NCI, Public Domain, Wikimedia Commons
- Article image: Imagoiq, Wikimedia Commons
- Licence of the article image: CC BY-SA 4.0
