# Fulvestrant

Source: https://onco.cc/drugs/fulvestrant/  
OnCo record `fulvestrant` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Fulvestrant is a monthly intramuscular injection that degrades the oestrogen receptor rather than blocking it, the endocrine backbone paired with CDK4/6, PI3K and AKT inhibitors once aromatase inhibitors fail. Slow uptake and incomplete receptor degradation drove the search for oral degraders.

## Summary

First selective oestrogen receptor degrader (2002). Backbone of PALOMA-3, MONARCH 2, MONALEESA-3, SOLAR-1, CAPItello-291, INAVO120, and the control arm of every oral SERD trial. Limitations: intramuscular 500 mg injections, slow steady state, and incomplete ER degradation, which motivated oral SERDs and the PROTAC vepdegestrant.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-07
- Brand: Faslodex
- Modality: Injectable SERD
- Mechanism: Binds ER, blocks dimerisation and nuclear localisation, accelerates proteasomal degradation.
- Approvals: US 2002: HR+ advanced breast cancer after antioestrogen therapy; US 2017: First-line HR+ advanced breast cancer (FALCON)
- Dosing: Intramuscular; 500 mg on days 1, 15, 29, then monthly

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Fulvestrant
- FDA label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?query=Fulvestrant

## Connected records

- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [HR-positive metastatic breast cancer after CDK4/6 inhibitors](https://onco.cc/cancers/hr-positive-metastatic-post-cdk46/), [Invasive lobular carcinoma of the breast](https://onco.cc/cancers/invasive-lobular-carcinoma/), [Male breast cancer](https://onco.cc/cancers/male-breast-cancer/)
- technologies: [Endocrine therapy (SERMs, AIs, SERDs)](https://onco.cc/technologies/endocrine-therapy/), [FES PET (oestrogen receptor imaging)](https://onco.cc/technologies/fes-pet/)
- targets: [Estrogen receptor (ERα)](https://onco.cc/targets/estrogen-receptor/)
- companies: [AstraZeneca](https://onco.cc/companies/astrazeneca/)
- trials: [A Clinical Study of JS105 in Combination With Other Anti-tumor Therapies in Patients With Solid Tumors](https://onco.cc/trials/nct06208410/), [A Phase 1/2 Trial of TER-2013 in Patients With Solid Tumors Harboring AKT/PI3K/PTEN Pathway Alterations](https://onco.cc/trials/nct07109726/), [A Phase I/II Study of XZP-3287 in Metastasis Solid Tumors](https://onco.cc/trials/nct04539496/), [A Phase II Study Evaluating the Efficacy and Safety of Inavolisib Plus Ribociclib Plus Fulvestrant Versus Placebo Plus Ribociclib Plus Fulvestrant in Participants With Advanced Breast Cancer](https://onco.cc/trials/nct07405801/), [A Phase IIIB Study to Evaluate the Use of Capivasertib in Combination With Fulvestrant in Patients With Advanced Breast Cancer Who Have Relapsed/Progressed on ET and CDK4/6 Inhibitor Reflecting Real World Clinical Practice in Spain](https://onco.cc/trials/nct06764186/), [A Study Evaluating the Efficacy and Safety of Giredestrant Compared With Physician's Choice of Endocrine Monotherapy in Participants With Previously Treated Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer (acelERA Breast Cancer)](https://onco.cc/trials/nct04576455/), [A Study Evaluating the Efficacy and Safety of Inavolisib Plus Fulvestrant Compared With Alpelisib Plus Fulvestrant in Participants With HR-Positive, HER2-Negative, PIK3CA Mutated, Locally Advanced or Metastatic Breast Cancer Post CDK4/6i and Endocrine Combination Therapy](https://onco.cc/trials/nct05646862/), [A Study of Abemaciclib (LY2835219) Combined With Fulvestrant in Women With Hormone Receptor Positive HER2 Negative Breast Cancer](https://onco.cc/trials/nct02107703/), [A Study of Abemaciclib (LY2835219) in Participants With Breast Cancer](https://onco.cc/trials/nct02763566/), [A Study of HRS-6208 in Combination With HRS-8080, or Fulvestrant, or Letrozole, With or Without HRS-6209 in Patients With Advanced Unresectable or Metastatic Breast Cancer](https://onco.cc/trials/nct07389733/), [A Study of MK-5684 in People With Certain Solid Tumors (MK-5684-015/OMAHA-015)](https://onco.cc/trials/nct06979596/), [A Study of TQB2930 for Injection Monotherapy or Combination Therapy in Patients With Recurrent/Metastatic Breast Cancer](https://onco.cc/trials/nct06202261/), [A Study to Evaluate Efficacy and Safety of Giredestrant Compared With Fulvestrant (Plus a CDK4/6 Inhibitor), in Participants With ER-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy (pionERA Breast Cancer)](https://onco.cc/trials/nct06065748/), [A Study to Investigate Efficacy and Safety With Oral AZD9833 Compared With Intramuscular Fulvestrant in Post-menopausal Women at Least 18 Years of Age With Advanced ER-positive HER2 Negative Breast Cancer](https://onco.cc/trials/nct04214288/), [A Study to Learn About the Study Medicine (Called PF-07220060 in Combination With PF-07104091) In Participants With Breast Cancer and Solid Tumors](https://onco.cc/trials/nct05262400/), [A Trial of HRS-6209 in Combination With Fulvestrant, Letrozole, HRS-8080, or HRS-1358 in Breast Cancer Patients](https://onco.cc/trials/nct06555068/), [Basket Study of Tucatinib and Trastuzumab in Solid Tumors With HER2 Alterations](https://onco.cc/trials/nct04579380/), [CAPItello-291](https://onco.cc/trials/capitello-291/), [Capivasertib + CDK4/6i + Fulvestrant for Advanced/Metastatic HR+/HER2- Breast Cancer (CAPItello-292)](https://onco.cc/trials/nct04862663/), [Capivasertib+Fulvestrant asTreatment for Locally Advanced(Inoperable) or Metastatic HR+/HER2- Breast Cancer in Chinese Patients](https://onco.cc/trials/nct06635447/), [CFI-402257, a Potent and Selective TTK Inhibitor, in Solid Tumors and With Fulvestrant in Breast Cancer](https://onco.cc/trials/nct05251714/), [Clinical Trial of Alpelisb and Tucatinib in Patients With PIK3CA-Mutant HER2+ Metastatic Breast Cancer.](https://onco.cc/trials/nct05230810/), [Comparison of Fulvestrant (FASLODEX™) 250 mg and 500 mg in Postmenopausal Women With Oestrogen Receptor Positive Advanced Breast Cancer Progressing or Relapsing After Previous Endocrine Therapy.](https://onco.cc/trials/nct00099437/), [DAWNA-1](https://onco.cc/trials/dawna-1/), [DNA-guided Second Line Adjuvant Therapy for High Residual Risk, Estrogen Receptor Positive, HER-2 Negative Breast Cancer (DARE)](https://onco.cc/trials/nct04567420/), [Efficacy and Safety of Tinengotinib Tablets Combined With Fulvestrant Injection in Patients With HR Positive and HER-2 Negative Recurrent or Metastatic Breast Cancer Who Have Failed Prior Treatment](https://onco.cc/trials/nct07498478/), [Evaluation of Lasofoxifene Combined With Abemaciclib Compared With Fulvestrant Combined With Abemaciclib in Locally Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation](https://onco.cc/trials/nct05696626/), [Evaluation of TQB3616 Capsules in a Phase II Clinical Trial for Recurrent/Metastatic Breast Cancer](https://onco.cc/trials/nct06702618/), [First-in-Human Study of Tersolisib (STX-478) as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors](https://onco.cc/trials/nct05768139/), [Futibatinib in Patients Previously Enrolled in an Antecedent Futibatinib as Monotherapy or Combination Therapy.](https://onco.cc/trials/nct06506955/), [Gedatolisib Plus Fulvestrant With or Without Palbociclib vs Standard-of-Care for the Treatment of Patients With Advanced or Metastatic HR+/HER2- Breast Cancer (VIKTORIA-1)](https://onco.cc/trials/nct05501886/), [INAVO120](https://onco.cc/trials/inavo120/), [OP-1250 (Palazestrant) vs. Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer](https://onco.cc/trials/nct06016738/), [Open-Label Study to Evaluate the Safety, Tolerability, PK, and Efficacy of INX-315 in Patients With Advanced Cancer](https://onco.cc/trials/nct05735080/), [ORION-1: Study of AVZO-023 as a Single Agent and in Combination With AVZO-021, and/or Endocrine Therapy in Advanced Solid Tumors](https://onco.cc/trials/nct06998407/), [PF-07104091 as a Single Agent and in Combination Therapy](https://onco.cc/trials/nct04553133/), [Phase 1/1b/2 Study of Oral PMD-026 in Patients With Metastatic Breast Cancer](https://onco.cc/trials/nct04115306/), [Phase 1/2 Study of ETX-636 in Participants With Advanced Solid Tumors](https://onco.cc/trials/nct06993844/), [Phase 1/2 Study to Evaluate EP0062 as Monotherapy and in Combination in Patients With Advanced or Metastatic AR+/HER-2-/ER+ Breast Cancer](https://onco.cc/trials/nct05573126/), [Phase 3 Study of Gedatolisib as First-Line Treatment for Patients With HR-Positive, HER2-Negative Advanced Breast Cancer (VIKTORIA-2)](https://onco.cc/trials/nct06757634/), [Phase Ib/II Clinical Study of QLS1304 Combined With Endocrine Therapy in the Treatment of ER+/HER2- Breast Cancer Patients](https://onco.cc/trials/nct07235176/), [plasmaMATCH](https://onco.cc/trials/plasmamatch/), [postMONARCH](https://onco.cc/trials/postmonarch/), [Sapanisertib and Serabelisib (PIKTOR) in Various Combinations in Patients With HR+/HER2- Advanced/Metastatic Breast Cancer](https://onco.cc/trials/nct07558733/), [Saruparib (AZD5305) Plus Camizestrant or Plus Endocrine Therapy, Compared With CDK4/6 Inhibitor Plus Endocrine Therapy or Plus Camizestrant in HR-Positive, HER2-Negative (IHC 0, 1+, 2+/ ISH Non-amplified), BRCA1, BRCA2, or PALB2m Advanced Breast Cancer](https://onco.cc/trials/nct06380751/), [Sirolimus for Injection (Albumin-bound) in Combination With Endocrine Therapy for HR+/HER2- Advanced/Metastatic Breast Cancer Patients Who Have Failed Standard Therapy](https://onco.cc/trials/nct06957379/), [SNV4818 in Participants With Advanced Solid Tumors](https://onco.cc/trials/nct06736704/), [SOLAR-1](https://onco.cc/trials/solar-1/), [Study Assessing the Efficacy and Safety of Treatment With Alpelisib Plus Fulvestrant in Japanese Men and Postmenopausal Women With Advanced Breast Cancer](https://onco.cc/trials/nct04524000/), [Study Assessing the Efficacy and Safety of Treatment With Alpelisib Plus Fulvestrant Versus Placebo Plus Fulvestrant in Chinese Men and Postmenopausal Women With Advanced Breast Cancer](https://onco.cc/trials/nct04544189/), [Study for Participants Continuing From Pfizer-sponsored Palbociclib (a Study Medicine) Studies](https://onco.cc/trials/nct05226871/), [Study of AMXT 1501 and DFMO in Combination With Standard Therapies in Advanced Solid Tumors](https://onco.cc/trials/nct07287917/), [Study of AVZO-021 in Patients With Advanced Solid Tumors](https://onco.cc/trials/nct05867251/), [Study of Belzutifan (MK-6482) Plus Fulvestrant for ER+/HER2- Metastatic Breast Cancer (MK-6482-029/LITESPARK-029)](https://onco.cc/trials/nct06428396/), [Study of ECI830 Single Agent or in Combination in Patients With Advanced HR+/HER2- Breast Cancer and in Patients With Other Advanced Solid Tumors](https://onco.cc/trials/nct06726148/), [Study of GVV858 as a Single Agent or in Combination With Endocrine Therapy in Patients With HR+/HER2- Breast Cancer and Other Advanced Solid Tumors](https://onco.cc/trials/nct07288359/), [Study of PF-07248144 in Advanced or Metastatic Solid Tumors](https://onco.cc/trials/nct04606446/), [Study to Assess the Efficacy and Safety of Alpelisib Plus Fulvestrant in Participants With HR-positive (HR+), HER2-negative, Advanced Breast Cancer After Treatment With a CDK4/6 Inhibitor and an Aromatase Inhibitor.](https://onco.cc/trials/nct05038735/), [Study to Evaluate Efficacy & Safety of Afuresertib Plus Fulvestrant in Patients With Locally Advanced or Metastatic HR+/HER2- Breast Cancer](https://onco.cc/trials/nct04851613/), [Study to Test the Safety and Tolerability of PF-07220060 in Participants With Advance Solid Tumors](https://onco.cc/trials/nct04557449/), [To Study the Effect of Inavolisib in Combination With Fulvestrant in Participants With Breast Cancer](https://onco.cc/trials/nct07368998/), [VERITAC-2](https://onco.cc/trials/veritac-2/)
- terms: [Oral SERD](https://onco.cc/terms/oral-serd/), [Selective oestrogen receptor degrader (SERD)](https://onco.cc/terms/serd/)
- pairings: [PI3K/AKT-pathway inhibitor + endocrine therapy (± CDK4/6)](https://onco.cc/pairings/pi3k-pathway-plus-endocrine/)
- people: [François-Clément Bidard](https://onco.cc/people/francois-clement-bidard/)
- biomarkers: [ER status (oestrogen receptor by IHC)](https://onco.cc/biomarkers/er-status/), [PR status (progesterone receptor by IHC)](https://onco.cc/biomarkers/pr-status/)
- roadmaps: [Hormonal therapy roadmap: removing the ovaries → tamoxifen → oral degraders switched by a blood test](https://onco.cc/roadmaps/hormonal-therapy-roadmap/)
- pathways: [Breast cancer (KEGG map)](https://onco.cc/pathways/breast-cancer-signalling/), [Chemical carcinogenesis - receptor activation](https://onco.cc/pathways/chemical-carcinogenesis-receptor-activation/)

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JSON: https://onco.cc/api/v1/entities/fulvestrant.json