Guardant Health Could Benefit From AstraZeneca Trial Failure, UBS Says

03:02 PM EDT, 09/15/2026 (MT Newswires) -- Guardant Health (GH) stands to benefit from AstraZeneca's (AZN) failed Serena-4 trial because the result preserves the biomarker-driven monitoring approach supporting potential demand for its Guardant360 test, UBS Securities said. The investment firm said AstraZeneca's phase III Serena-4 trial testing camizestrant plus palbociclib as upfront first-line treatment for HR-positive/HER2-negative advanced breast cancer missed statistical significance for progression-free survival versus anastrozole plus palbociclib, despite a numerical improvement. UBS said a positive result would have reduced the need to monitor patients for ESR1 mutations to determine camizestrant eligibility. Instead, the failure preserves the approach established by the earlier Serena-6 trial, under which patients are monitored during first-line therapy and switched to camizestrant once an ESR1 mutation emerges but before radiographic progression. AstraZeneca said the outcome reinforces the importance of ESR1 testing, according to the note Monday. The analysts said this supports a broader companion-diagnostic case for Guardant360 and represents potential volume and revenue upside to their model. UBS has a buy rating on the stock, with a $225 price target. Shares of Guardant Health were up 5.6% in Tuesday trading. Price: 177.18, Change: +9.34, Percent Change: +5.56