Head-to-head evidence
Anastrozole vs Exemestane
Same mechanism, same race: design-graded trial evidence for both assets, with the grading rationale shown. Grades describe the quality of the evidence, never the merits of either security.
HR+/HER2- Metastatic Breast Cancer
Shared mechanism: Aromatase · full HR+/HER2- Metastatic Breast Cancer pipeline
Anastrozole
Marketed by AstraZeneca and partners
NCT00291759 · Phase 3 · completed
The trial was large and randomized, with an active tamoxifen comparator, but it was open-label rather than blinded. Registry results were not posted at the time of grading; the key result shown was recovered from the cited external source.
Next expected readout: November 2026 · NCT04906395 (registry estimate)
Exemestane
Marketed by Pfizer
NCT00038467 · Phase 3 · completed
This was a randomized, double-blind, active-controlled trial with 4,724 participants (2,352 assigned to exemestane and 2,372 to tamoxifen). The hard clinical primary endpoint, 36-month disease-free survival, was statistically significantly better with exemestane (90% vs 86%; hazard ratio 0.69, p=0.00003).
Next expected readout: November 2026 · NCT04906395 (registry estimate)
The full competitive landscape for each asset (every same-race competitor with aligned evidence, sortable) is on the asset pages: Anastrozole's landscape · Exemestane's landscape