Head-to-head evidence
Fulvestrant vs Giredestrant
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: Estrogen receptor · full HR+/HER2- Metastatic Breast Cancer pipeline
Fulvestrant · Faslodex
Marketed by AstraZeneca
NCT00635713 · Phase 3 · completed
The trial randomized an estimated 588 participants and used double blinding to compare two active treatment groups: fulvestrant 125 mg plus anastrozole versus fulvestrant 250 mg plus anastrozole. Its primary endpoint was time to tumor progression, a clinical outcome. Registry results were not posted at the time of grading; the key result shown was recovered from the cited external source.
Next expected readout: October 2026 · NCT04851613 (registry estimate)
Giredestrant
Developed by Roche
NCT04436744 · Phase 2 · completed
This was a randomized but unblinded trial of 221 patients using a tumor biomarker (Ki67), rather than a hard clinical outcome such as tumor response or survival, as its primary measure; the giredestrant combination produced a statistically significant reduction in this biomarker compared with the anastrozole combination.
Next expected readout: July 2027 · NCT03332797 (registry estimate)
The full competitive landscape for each asset (every same-race competitor with aligned evidence, sortable) is on the asset pages: Fulvestrant's landscape · Giredestrant's landscape