Breast cancer (invasive) · line 2 · Elacestrant monotherapy (HR+/HER2- ESR1-mutant metastatic post-AI/CDK4/6i)

Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.

Knowledge-base record for audit. Provisional clinical content: this is not a prescription. An oncologist must verify original sources, applicability and review status. Full rules and constraints are in the YAML.

Source YAML: complete record

Line of therapy	2
Track	standard
Linked regimen	`REG-ELACESTRANT-BREAST`

ID	`IND-BREAST-HR-POS-2L-ESR1-ELACESTRANT`
Type	Indication
Status	reviewed 2026-04-27 \| pending_clinical_signoff
Diseases	`DIS-BREAST`
Sources	`SRC-EMERALD-BIDARD-2022` `SRC-ESMO-BREAST-METASTATIC-2024` `SRC-NCCN-BREAST-2025`

Notes

ESCAT IA. EMERALD established elacestrant (oral SERD) for ESR1-mutant HR+/HER2- after AI ± CDK4/6i progression. ESR1 mutations are acquired on AI therapy (~30-40% of post-AI metastatic) and predict AI resistance — ctDNA testing at progression is the preferred detection method (subclonal, polyclonal in tissue). Modest absolute PFS gain in overall ESR1-mut cohort (3.8 vs 1.9 mo) but enriched in long-CDK4/6i-exposed subgroup. Other oral SERDs (camizestrant, giredestrant, imlunestrant) and PROTACs (vepdegestrant) in late development. UA access barrier: elacestrant not registered; named-patient import / EAP / cross-border only.

Used By

Algorithms

ALGO-BREAST-HR-POS-2L - ALGO-BREAST-HR-POS-2L

Handbook Chapters

HB-BREAST-HR-POS-HER2-NEG-1L - HR+/HER2- metastatic breast cancer: first-line reasoning