AstraZeneca’s gastric ADC: strong survival signal, but second-line reach is uncertain

The ESMO coverage suggests AstraZeneca may need to temper expectations for sonesitatug vedotin (Sone‑Ve) as a broad second-line gastric-cancer treatment, while the case appears stronger in third-line and later disease.

In Phase III CLARITY-Gastric01, Sone‑Ve improved overall survival:
median 10.6 months versus 6.4 months for investigator’s-choice treatment across the second-line-and-later population (hazard ratio 0.58). In the third-line-and-later group, median survival was 10 versus 5 months, with a 53% lower risk of death reported.

The caution is that the trial missed its blinded independent review progression-free survival endpoint:
median PFS was 4.2 months with Sone‑Ve versus 3.8 months with control. Investigator-assessed PFS was more favorable, at 4.4 versus 3 months.

An ESMO commentator said the PFS result makes Sone‑Ve’s role in second-line treatment less certain, but it could become an important option in third-line and later settings. AstraZeneca argues the survival benefit and other findings make the data robust enough to take to regulators.

Bottom line:
the results support meaningful potential, especially later in treatment, but the PFS miss clouds the breadth of the initial opportunity. The available reports do not establish that AstraZeneca has formally narrowed its expectations.