Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Fulvestrant”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2005

Preclinical and clinical experience with fulvestrant (Faslodex) in postmenopausal women with hormone receptor-positive advanced breast cancer.

Fulvestrant (Faslodex) is a new type of estrogen receptor (ER) antagonist that binds, blocks, and degrades the ER, leading to reduced expression of the progesterone receptor (PgR). Unlike the selective ER modulator tamoxifen, fulvestrant is devoid of any known agonist activity. Fulvestrant has a steroidal structure that competitively binds to the ER with an affinity much greater than that of tamoxifen. After binding to fulvestrant, degradation of the ER is accelerated, ultimately resulting in a reduction in cellular ER. Immunohistochemical studies have demonstrated that a single intramuscular injection of fulvestrant results in a dose-dependent decrease in ER and PgR indices and in Ki-67 expression. At the approved 250 mg dose, the decrease in receptor positivity with fulvestrant treatment was greater than that with tamoxifen. Phase III clinical trials have demonstrated the clinical benefit of fulvestrant in the endocrine treatment of breast cancer. Among patients who progressed during adjuvant or first-line endocrine therapy, fulvestrant was at least as effective as anastrozole as second-line treatment for the primary endpoints of objective response and time to progression, and was well tolerated. After a median follow-up of 24.5 months, a combined survival analysis from two Phase III studies has shown that fulvestrant may be considered similar to anastrozole for time to death (27.4 months versus 27.7 months, respectively). For the first-line therapy of advanced breast cancer in postmenopausal women, fulvestrant was shown to be active and well tolerated in a trial that compared fulvestrant 250 mg once monthly and tamoxifen 20 mg once daily. Treatment with fulvestrant has also demonstrated clinical efficacy among patients who progressed following treatment with tamoxifen followed by nonsteroidal aromatase inhibitors. The efficacy of fulvestrant in sequential endocrine therapy and in combination with other agents appears promising and active investigations are ongoing to explore the clinical potential of this novel antiestrogen.

Aged↗
PubMed2003

Fulvestrant versus anastrozole for the treatment of advanced breast carcinoma in postmenopausal women: a prospective combined analysis of two multicenter trials.

BACKGROUND: Fulvestrant (ICI 182,780) is a new type of estrogen receptor (ER) antagonist that down-regulates the ER and has no known agonist effects. The authors report the prospectively planned combined analysis of data from 2 Phase III trials comparing fulvestrant 250 mg monthly (n=428) and anastrozole 1 mg daily (n=423) in postmenopausal women with advanced breast carcinoma (ABC) who previously had progressed after receiving endocrine treatment. METHODS: The primary endpoint was time to progression (TTP). Secondary endpoints included objective response (OR), duration of response (DOR), and tolerability. The trials were designed to demonstrate superiority of fulvestrant over anastrozole. Noninferiority of fulvestrant versus anastrozole was determined using a retrospectively applied statistical test. RESULTS: At a median follow-up of 15.1 months, approximately 83% of patients in each treatment arm had progressed. The median TTP was 5.5 months in the fulvestrant group and 4.1 months in the anastrozole group, and the OR rates were 19.2% and 16.5% for fulvestrant and anastrozole, respectively (although the difference between treatments was not statistically significant). In patients who responded, further follow-up (median, 22.1 months) was performed to obtain more complete information on DOR; the median DOR (from randomization to disease progression) in patients who responded to treatment was 16.7 months in the fulvestrant group and 13.7 months in the anastrozole group. In a statistical analysis of DOR (using all randomized patients; from the start of response to disease progression), DOR was significantly longer for patients in the fulvestrant group compared with patients in the anastrozole group. Both drugs were tolerated well; withdrawals due to drug-related adverse events were 0.9% and 1.2% in the fulvestrant group and the anastrozole group, respectively. The incidence of joint disorders was significantly lower in the fulvestrant group (P=0.0036). CONCLUSIONS: Fulvestrant was tolerated well and was at least as effective as anastrozole in the second-line treatment of patients with ABC. This new hormonaltherapy may provide a valuable treatment option for ABC in postmenopausal women.

Adult↗
PubMed2003

Fulvestrant: an estrogen receptor antagonist that downregulates the estrogen receptor.

Fulvestrant, a novel antiestrogen classified as an estrogen receptor antagonist without known agonist effects, was recently approved in the United States for the treatment of postmenopausal, hormone receptor-positive women with progressive metastatic breast cancer after antiestrogen therapy. In a phase II trial, monthly administration of fulvestrant, 250 mg intramuscularly, conferred clinical benefit (partial response or stable disease for >or= 24 weeks) in 69% of patients with tamoxifen-resistant advanced breast cancer. Furthermore, the median duration of response and survival for this population (26 and 54 months, respectively) was twice as high as those documented for a megestrol acetate-treated historical cohort (14 months and 30 months, respectively). Comparative phase III trials conducted in North America and internationally, which used time to progression as the primary endpoint, demonstrated fulvestrant's tolerability and equivalence to anastrozole in postmenopausal women with tamoxifen-resistant advanced breast cancer, which led to its approval in this setting. Vasodilation and nausea were the principal treatment-related adverse events in the fulvestrant arms, and mild injection-site reactions occurred in 4.6% and 1.1% of monthly fulvestrant courses given in the North American and international trials, respectively. Recent subanalyses of the pivotal phase III data have found that fulvestrant produces a 30% longer mean duration of response compared with anastrozole and that fulvestrant-induced estrogen receptor downregulation does not preclude response to subsequent hormonal therapy. Ongoing trials in patients with advanced breast cancer will provide further insight into the relative merits of fulvestrant versus tamoxifen as first-line therapy for metastatic disease, the use of fulvestrant within combination and sequential regimens, and the efficacy of fulvestrant specifically in premenopausal women. Research efforts focusing on alternate administration schedules for fulvestrant and its potential as an adjuvant hormonal therapy are also anticipated.

Antineoplastic Agents, Hormonal↗
PubMed2006

Fulvestrant (ICI 182,780)-dependent interacting proteins mediate immobilization and degradation of estrogen receptor-alpha.

The antiestrogen fulvestrant (ICI 182,780) causes immobilization of estrogen receptor-alpha (ERalpha) in the nuclear matrix accompanied by rapid degradation by the ubiquitin-proteasome pathway. In this study we tested the hypothesis that fulvestrant induces specific nuclear matrix protein-ERalpha interactions that mediate receptor immobilization and turnover. A glutathione S-transferase (GST)-ERalpha-activating function-2 (AF2) fusion protein was used to isolate and purify receptor-interacting proteins in cell lysates prepared from human MCF-7 breast cancer cells. After SDS-PAGE and gel excision, mass spectrometry was used to identify two major ERalpha-interacting proteins, cytokeratins 8 and 18 (CK8.CK18). We determined, using ERalpha-activating function-2 mutants, that helix 12 (H12) of ERalpha, but not its F domain, is essential for fulvestrant-induced ERalpha-CK8 and CK18 interactions. To investigate the in vivo role of H12 in fulvestrant-induced ERalpha immobilization/degradation, transient transfection assays were performed using wild type ERalpha,ERalpha with a mutated H12, and ERalpha with a deleted F domain. Of those, only the ERalpha H12 mutant was resistant to fulvestrant-induced immobilization to the nuclear matrix and protein degradation. Fulvestrant treatment caused ERalpha degradation in CK8.CK18-positive human breast cancer cells, and CK8 and CK18 depletion by small interference RNAs partially blocked fulvestrant-induced receptor degradation. Furthermore, fulvestrant-induced ERalpha degradation was not observed in CK8 or CK18-negative cancer cells, suggesting that these two intermediate filament proteins are necessary for fulvestrant-induced receptor turnover. Using an ERalpha-green fluorescent protein construct in fluorescence microscopy revealed that fulvestrant-induced cytoplasmic localization of newly synthesized receptor is mediated by its interaction with CK8 and CK18. In summary, this study provides the first direct evidence linking ERalpha immobilization and degradation to the nuclear matrix. We suggest that fulvestrant induces ERalpha to interact with CK8 and CK18, drawing the receptor into close proximity to nuclear matrix-associated proteasomes that facilitate ERalpha turnover.

Breast Neoplasms↗
PubMed2004

Pharmacokinetic profile of intramuscular fulvestrant in advanced breast cancer.

OBJECTIVE: To characterise the pharmacokinetics of a long-acting formulation of fulvestrant following intramuscular administration of single and multiple doses. STUDY DESIGN: Pharmacokinetic investigations of single and multiple doses of fulvestrant were conducted within two global phase III efficacy studies that compared intramuscular fulvestrant with oral anastrozole in postmenopausal women with hormone-sensitive advanced breast cancer (study 0020, conducted in Europe, Australia and South Africa, and study 0021, conducted in North America). METHODS: Patients received once-monthly intramuscular injections of fulvestrant 250 mg (1 x 5 mL for < or =21 months in study 0020; 2 x 2.5 mL for < or =30 months in study 0021). Serial blood samples were collected for the first 28 days after the initial dose and immediately prior to all subsequent monthly doses. Plasma fulvestrant concentrations were determined by high-performance liquid chromatography-tandem mass spectrometry. PATIENTS: Twenty-six (study 0020) and 193 (study 0021) postmenopausal women, comprising the pharmacokinetic subgroups of the phase III efficacy trials, were studied. Patients had shown disease progression or recurrence following previous hormonal therapy for advanced disease or had relapsed after adjuvant endocrine therapy with a nonsteroidal antiestrogen. OUTCOME MEASURES AND RESULTS: For single-dose fulvestrant 250 mg, area under the concentration-time curve from time zero to 28 days (AUC(28)), maximum observed plasma concentration (C(max)), minimum observed plasma concentration at 28 days (C(min)) and time to maximum plasma concentration (t(max)) were determined. For multiple-dose fulvestrant 250 mg once monthly, steady-state trough concentrations (C(trough)) were determined. Plasma fulvestrant concentrations reached a peak at a median of 7 days (range 2-8 days) postdose, and declined biexponentially with a slower phase commencing approximately 2-3 weeks postdose. Intersubject variability in C(max) and AUC(28) was approximately 6-fold and 4-fold, respectively. Mean parameters for single-dose fulvestrant were: AUC(28), 148 microg. day/L; C(max), 8.2 microg/L; C(min), 2.6 microg/L; t(max), 7.0 days. Geometric mean C(trough) increased from 2.57 to 6.15 microg/L (study 0020) and from 2.38 to 6.52 microg/L (study 0021) over the first 6 months, reaching steady-state concentrations of approximately 6-7 microg/L (study 0020) or 9 microg/L (study 0021). Preliminary pharmacokinetic analysis, using a naive pooled data approach, suggests that observed single- and multiple-dose plasma profiles can be adequately described with a two-compartment kinetic model. Model-generated steady-state AUC(28) values were approximately 300 microg. day/L. CONCLUSIONS: The intramuscular formulation of fulvestrant displays predictable kinetics and approximately 2-fold accumulation on administration once monthly. At the proposed therapeutic dosage (250 mg once monthly), plasma fulvestrant concentrations are maintained within a narrow range throughout the administration interval, thus ensuring stable systemic drug exposure during long-term treatment.

Adult↗
PubMed2004

Fulvestrant: a review of its use in hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy.

Fulvestrant (Faslodex) is a novel estrogen receptor (ER) antagonist that competitively binds to the ER with a much greater affinity than that of tamoxifen. The downregulation of cellular levels of the ER protein results in complete abrogation of estrogen-sensitive gene transcription. This distinct mechanism of action ensures a lack of cross resistance with other hormonal agents and, in contrast to tamoxifen, fulvestrant has no known estrogen-agonist effects. Fulvestrant is administered via monthly intramuscular injections (250mg) and is recommended for the treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy. The efficacy of fulvestrant was similar to that of the aromatase inhibitor anastrozole (1 mg/day) in two, well designed studies in postmenopausal women with locally advanced or metastatic breast cancer that had progressed during prior antiestrogen therapy. Time to disease progression (primary endpoint) and treatment failure, rates of objective response and clinical benefit, overall survival and quality of life were similar in patients treated with fulvestrant or anastrozole. In retrospective noninferiority analyses, fulvestrant was at least as effective as anastrozole in all randomised patients, and in those with or without visceral metastases. Fulvestrant is generally well tolerated and was tolerated as well as anastrozole in clinical trials. Treatment-related adverse events were mostly mild to moderate and led to treatment withdrawal in about 1% of patients who received fulvestrant or anastrozole. The main adverse effects associated with therapy are nausea, asthenia, pain, vasodilation and headache.In conclusion, monthly intramuscular injections of fulvestrant are at least as effective and as well tolerated as oral anastrozole once daily in the treatment of postmenopausal women with advanced breast cancer that has progressed on prior antiestrogen therapy. Because of a different mode of action to that of other hormonal agents, fulvestrant is effective in the treatment of tamoxifen-resistant disease and, unlike tamoxifen, has no known estrogen agonist effects. Thus, fulvestrant provides an effective and well tolerated option for the treatment of hormone receptor-positive metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy.

Anastrozole↗
PubMed2002

Fulvestrant, formerly ICI 182,780, is as effective as anastrozole in postmenopausal women with advanced breast cancer progressing after prior endocrine treatment.

PURPOSE: To compare the efficacy and tolerability of fulvestrant (formerly ICI 182,780) and anastrozole in postmenopausal women with advanced breast cancer progressing after prior endocrine treatment. PATIENTS AND METHODS: Patients (n = 451) with advanced breast cancer were randomized to receive fulvestrant 250 mg as a once-monthly (one x 5 mL) intramuscular injection or an oral dose of anastrozole 1 mg in this open, parallel-group, multicenter trial. The primary end point was time to progression (TTP). Secondary end points included objective response (OR) rates, defined as complete response (CR) or partial response (PR), duration of response (DOR), and tolerability. RESULTS: Patients were followed for a median period of 14.4 months. In terms of TTP, fulvestrant was as effective as anastrozole (hazard ratio, 0.98; confidence interval [CI], 0.80 to 1.21; P =.84). Median TTP was 5.5 months for fulvestrant and 5.1 months for anastrozole. OR rates showed a numerical advantage for fulvestrant (20.7%) over anastrozole (15.7%) (odds ratio, 1.38; CI, 0.84 to 2.29; P =.20). Clinical benefit rates (CR + PR + stable disease > or = 24 weeks) were 44.6% for fulvestrant and 45.0% for anastrozole. Median DOR was 14.3 months for fulvestrant and 14.0 months for anastrozole. Both treatments were well tolerated, with 3.2% and 1.3% of fulvestrant- and anastrozole-treated patients, respectively, withdrawn from treatment because of an adverse event. CONCLUSION: Fulvestrant was as effective as anastrozole. These data confirm that fulvestrant is an additional, effective, and well-tolerated treatment for advanced breast cancer in postmenopausal women whose disease progressed on prior endocrine therapy.

Adult↗
PubMed2002

Double-blind, randomized trial comparing the efficacy and tolerability of fulvestrant versus anastrozole in postmenopausal women with advanced breast cancer progressing on prior endocrine therapy: results of a North American trial.

PURPOSE: To compare the efficacy and tolerability of fulvestrant (formerly ICI 182,780) with anastrozole in the treatment of advanced breast cancer in patients whose disease progresses on prior endocrine treatment. PATIENTS AND METHODS: In this double-blind, double-dummy, parallel-group study, postmenopausal patients were randomized to receive either an intramuscular injection of fulvestrant 250 mg once monthly or a daily oral dose of anastrozole 1 mg. The primary end point was time to progression (TTP). Secondary end points included objective response (OR) rate, duration of response (DOR), and tolerability. RESULTS: Patients (n = 400) were followed for a median period of 16.8 months. Fulvestrant was as effective as anastrozole in terms of TTP (hazard ratio, 0.92; 95.14% confidence interval [CI], 0.74 to 1.14; P =.43); median TTP was 5.4 months with fulvestrant and 3.4 months with anastrozole. OR rates were 17.5% with both treatments. Clinical benefit rates (complete response + partial response + stable disease > or = 24 weeks) were 42.2% for fulvestrant and 36.1% for anastrozole (95% CI, -4.00% to 16.41%; P =.26). In responding patients, median DOR (from randomization to progression) was 19.0 months for fulvestrant and 10.8 months for anastrozole. Using all patients, DOR was significantly greater for fulvestrant compared with anastrozole; the ratio of average response durations was 1.35 (95% CI, 1.10 to 1.67; P < 0.01). Both treatments were well tolerated. CONCLUSION: Fulvestrant was at least as effective as anastrozole, with efficacy end points slightly favoring fulvestrant. Fulvestrant represents an additional treatment option for postmenopausal women with advanced breast cancer whose disease progresses on tamoxifen therapy.

Adult↗
PubMed2007

Role for HER2/neu and HER3 in fulvestrant-resistant breast cancer.

Tamoxifen resistance is common for estrogen receptor alpha (ERalpha) positive breast cancer. Second-line therapies include aromatase inhibitors or fulvestrant. We have shown previously that fulvestrant reversed 17beta-estradiol-induced tumor regression of tamoxifen-stimulated MCF-7 xenografts (MCF-7TAMLT) treated for >5 years with tamoxifen in athymic mice and paradoxically stimulated growth. We investigated mechanisms responsible for growth by fulvestrant in the presence of physiologic estradiol and therapeutic strategies in vivo. The results demonstrated that only estradiol increased expression of the estrogen-responsive genes, c-myc, igf-1, cathepsin D, and pS2 mRNAs, in MCF-7E2 and MCF-7TAMLT tumors. Tamoxifen or fulvestrant decreased the estradiol-induced increase of these mRNAs in both tumor models. However, tyrosine-phosphorylated HER2/ neu, HER3, phospho-extracellular-regulated kinase-1/2 (ERK-1/2), and phospho-glycogen synthetase kinase 3alpha (GSK3alpha) and beta proteins were increased in MCF-7TAMLT tumors treated with fulvestrant compared to estradiol, control, or tamoxifen. Phospho-HER2/neu interacted with HER3 protein in MCF-7TAMLT tumors. In order to determine whether the functional interaction of HER2/neu with HER3 is critical for growth of fulvestrant-stimulated MCF-7TAMLT tumors, pertuzumab (an antibody that blocks HER2/neu-HER3 interaction) was used in an in vivo xenograft growth assay. Only growth of fulvestrant-treated MCF-7TAMLT xenografts was decreased significantly by 37.2% in response to pertuzumab (P=0.004). Pertuzumab specifically decreased the interaction of HER2/neu protein with HER3 in fulvestrant-stimulated MCF-7TAMLT tumors. These results suggested growth of MCF-7TAMLT tumors by tamoxifen or fulvestrant is potentially independent of ERalpha transcriptional activity as evidenced by lack of induction of four estrogen-responsive genes. The results suggested that growth of MCF-7TAMLT tumors treated with fulvestrant in the presence of physiologic estradiol is in part mediated through enhanced signaling from the HER2/neu-HER3 pathway as pertuzumab partially inhibited growth and the interaction of HER2/neu with HER3 in vivo.

Animals↗
PubMed2002

A phase I trial to assess the pharmacology of the new oestrogen receptor antagonist fulvestrant on the endometrium in healthy postmenopausal volunteers.

While tamoxifen use is associated with clear benefits in the treatment of hormone-sensitive breast cancer, it also exhibits partial oestrogen agonist activity that is associated with adverse events, including endometrial cancer. Fulvestrant ("Faslodex") is a new oestrogen receptor antagonist that downregulates the oestrogen receptor and has no known agonist effect. This single-centre, double-blind, randomised, parallel-group trial was conducted to determine the direct effects of fulvestrant on the female endometrium when given alone and in combination with the oestrogen, ethinyloestradiol. Following a 14-day, pretrial screening period, 30 eligible postmenopausal volunteers were randomised to receive fulvestrant 250 mg, fulvestrant 125 mg or matched placebo administered as a single intramuscular injection. Two weeks postinjection, volunteers received 2-weeks concurrent exposure to ethinyloestradiol 20 microg day(-1). Endometrial thickness was measured before and after the 14-day screening period with further measurements predose (to confirm a return to baseline) and on days 14, 28 and 42 post-treatment with fulvestrant. Pharmacokinetic and safety assessments were performed throughout the trial. Fulvestrant at a dose of 250 mg significantly (P=0.0001) inhibited the oestrogen-stimulated thickening of the endometrium compared with placebo. Neither the 125 mg nor 250 mg doses of fulvestrant demonstrated oestrogenic effects on the endometrium over the initial 14-day assessment period. Fulvestrant was well tolerated and reduced the incidence of ethinyloestradiol-related side effects. At the same dose level that is being evaluated in clinical trials of postmenopausal women with advanced breast cancer, fulvestrant (250 mg) is an antioestrogen with no evidence of agonist activity in the endometrium of healthy postmenopausal women.

Double-Blind Method↗
PubMed2004

Fulvestrant is an effective and well-tolerated endocrine therapy for postmenopausal women with advanced breast cancer: results from clinical trials.

Fulvestrant ('Faslodex') is a new type of endocrine treatment--an oestrogen receptor (ER) antagonist that downregulates the ER and has no agonist effects. Early efficacy data from phase I/II trials have demonstrated fulvestrant to be effective and well tolerated. Two randomised phase III trials have compared the efficacy of fulvestrant and the aromatase inhibitor, anastrozole, in postmenopausal women with advanced breast cancer progressing on prior endocrine therapy. Fulvestrant (intramuscular injection 250 mg month(-1)) was found to be at least as effective as anastrozole (orally 1 mg day(-1)) for time to progression (5.5 vs 4.1 months, respectively (hazard ratio (HR): 0.95; 95.14% confidence interval (CI), 0.82-1.10; P=0.48)) and objective response 19.2 vs 16.5%, respectively; treatment difference 2.75%; 95.14% CI, -2.27 to 9.05%; P=0.31). More recently, fulvestrant has also been shown to be noninferior to anastrozole in terms of overall survival, with median time to death being 26.4 months in fulvestrant-treated patients and 24.2 months in those treated with anastrozole (HR: 0.97; 95% CI, 0.78-1.21; P=0.82). In a further randomised phase III trial, fulvestrant was compared with tamoxifen as first-line therapy for advanced disease in postmenopausal women. In the overall population, efficacy differences favoured tamoxifen and noninferiority of fulvestrant could not be ruled out. In the prospectively defined subset of patients with ER-positive and/or progesterone receptor-positive disease, there was no statistically significant difference between fulvestrant and tamoxifen. This paper reviews the efficacy and tolerability results from these trials.

Animals↗
PubMed2006

Metastatic breast cancer: sequencing hormonal therapy and positioning of fulvestrant.

Fulvestrant, a novel estrogen receptor (ER) antagonist with no agonist effects, binds, blocks, and degrades the ER, thereby downregulating cellular ER levels, which in turn leads to reduced expression of the progesterone receptor. Due to this specific working mechanism, fulvestrant is an important addition to the armamentarium of endocrine agents in advanced breast cancer (ABC). Fulvestrant has been shown to be equally effective as the third-generation aromatase inhibitor (AI) anastrozole in postmenopausal patients with hormone-sensitive ABC progressing prior to tamoxifen. In another randomized phase III trial, it was shown that fulvestrant had similar efficacy to tamoxifen in the first-line treatment of postmenopausal women with hormone receptor-positive ABC. When comparing the side effects of fulvestrant with tamoxifen and anastrozole, it was shown that fulvestrant is well tolerated compared with these agents and is associated with a lower incidence of joint disorders. Clinical benefit on fulvestrant treatment after AI therapy has been reported in a substantial number of patients (28-46%). On the other hand, it was also shown that sensitivity to further endocrine therapy is retained following progression on first-line or second-line fulvestrant (57% and 46% clinical benefit, respectively). In conclusion, fulvestrant provides us with an additional endocrine treatment option making it possible to prolong the time that patients with ABC can be treated with endocrine therapy.

Antineoplastic Agents, Hormonal↗
PubMed2006

Endocrine response after prior treatment with fulvestrant in postmenopausal women with advanced breast cancer: experience from a single centre.

The pure anti-oestrogen fulvestrant has now been licensed for use in advanced breast cancer which has progressed on an anti-oestrogen. Optimal sequencing of various endocrine agents becomes very important in the therapeutic strategy. We report our experience of further endocrine response with another endocrine agent after prior fulvestrant treatment. Among all patients with advanced breast cancer who had been entered into five phase II/III trials using fulvestrant as first- to ninth-line endocrine therapy in our Unit since 1993, 54 patients who fulfilled the following criteria were studied for their subsequent endocrine response: (i) oestrogen receptor positive or unknown; (ii) having been on a subsequent endocrine therapy for > or =6 months unless the disease progressed before; and (iii) with disease assessable for response according to International Union Against Cancer criteria. Eleven patients had received an aromatase inhibitor prior to fulvestrant, which resulted in five CBs (clinical benefit = objective remission/stable disease (SD)) for > or =6 months). Twenty-eight patients achieved CB on fulvestrant. They went on subsequent endocrine therapy with two partial responses, 11 SDs and 15 PDs (progressive disease) at 6 months. The median survival from starting fulvestrant and subsequent endocrine therapy was respectively 46.6 and 18.2 months. Among the remaining 26 patients who progressed at 6 months on fulvestrant, there were three SDs and 23 PDs at 6 months on subsequent endocrine therapy. The median survival from starting fulvestrant and subsequent endocrine therapy was respectively 12.5 and 9.3 months. Of all these 54 patients, 30% (n = 16) therefore achieved CB using another (second- to tenth-line) endocrine agent (anastrozole = 26; tamoxifen = 12; megestrol acetate = 11; others = 5). It would thus appear that further endocrine response can be induced in a reasonable proportion of patients after failing fulvestrant.

Adult↗
PubMed2005

Effectiveness and tolerability of fulvestrant in postmenopausal women with hormone receptor-positive breast cancer.

Fulvestrant, an estrogen receptor antagonist that downregulates the estrogen receptor but has no known agonist effects, has been evaluated in 2 randomized trials involving postmenopausal women with hormone receptor-positive, progressive advanced-stage breast cancer after disease progression with antiestrogen therapy. These phase III studies, from which data were reported separately and in a planned combined analysis, showed that fulvestrant 250 mg per month intramuscularly was at least as effective as anastrozole 1 mg per day orally with respect to the primary endpoint of time to progression as well as secondary efficacy endpoints, which included objective response, clinical benefit, and survival. Both trials showed that patients treated with fulvestrant had a significantly longer duration of response, and a retrospective analysis found that pretreatment with fulvestrant did not preclude response to third-line hormonal therapy. More recently, fulvestrant was shown to be active as first-line hormonal therapy for advanced-stage breast cancer, with overall efficacy similar to that of tamoxifen in patients with hormone receptor-positive disease. Fulvestrant has been well tolerated in comparative trials published to date, translating into low study withdrawal rates and maintenance of quality of life. The incidence of adverse events was similar between the treatment arms in both trials of fulvestrant versus anastrozole, but it was notably lower for fulvestrant relative to tamoxifen in the first-line setting. In light of the results of comparative phase III trials, fulvestrant is effective and well tolerated in the treatment of postmenopausal women with hormone receptor-positive advanced-stage breast cancer.

Anastrozole↗
PubMed2005

Fulvestrant ("Faslodex"): clinical experience from the Compassionate Use Programme.

Fulvestrant ("Faslodex") is a new oestrogen receptor (ER) antagonist with no agonist effects that is licensed in the USA, Brazil, Europe and elsewhere for the treatment of advanced breast cancer (ABC) in postmenopausal women following progression on other endocrine agents. This report consolidates clinical experience from the "Faslodex" Compassionate Use Programme, including a total of 339 patients treated at eight cancer centres. Patients received fulvestrant as first- (n=22), second- (n=125), third- (n=105), fourth- (n=58), fifth- (n=22) or sixth-line (n=5) hormonal treatment for ABC, with two patients receiving fulvestrant after more than six other endocrine therapies. Objective response was achieved by 40 patients and stable disease lasting 6 months by 92 patients, giving overall clinical benefit (CB) in 132/339 patients (39%). The CB rate decreased as fulvestrant was used later in the sequence of endocrine treatments, from 46% (10/22) with first-line fulvestrant to 27% (6/22) with fifth-line fulvestrant. Increased benefit was found in patients with tumours expressing both ER and progesterone receptor (PgR) compared with other combinations, although good activity was reported in patients expressing either ER or PgR as well as in tumours expressing human epidermal growth factor receptor 2. Fulvestrant was well tolerated; adverse events were noted in 18/339 patients (5%). These findings concur with data from the clinical-trial setting and further support the assertion that greater benefit is derived when fulvestrant is used early in the treatment sequence.

Adult↗
PubMed2005

Fulvestrant ('Faslodex') in pre-treated patients with advanced breast cancer: a single-centre experience.

Fulvestrant ('Faslodex') is a new oestrogen receptor (ER) antagonist with no agonist effects. This report describes the experience of a single centre including 126 postmenopausal women with advanced breast cancer (ABC) in a fulvestrant Compassionate Use Programme. All patients had previously received endocrine treatment for early or ABC. Patients received fulvestrant as first- (n=7), second- (n=51), third- (n=50) or fourth-line endocrine therapy (n=18) for ABC (median duration of treatment: 4 months [range 3-27(+) months], follow-up: 13 months [range 1-38(+) months]). Twelve patients had partial responses (PR) and 43 patients experienced stable disease (SD) > or = 6 months (objective response rate: 9.5%; clinical benefit [CB] rate: 43.6%). Ten of 12 patients with a PR had HER2-negative tumours, and 9/12 had ER-positive and progesterone receptor (PgR)-positive disease (two patients had unknown HER2 status and one had unknown ER and PgR status). Nine of the 18 patients with HER2-positive tumours experienced CB with fulvestrant. Although CB rates were similar when fulvestrant was given as first- to fourth-line endocrine treatment, the proportion of those experiencing CB who had a PR appeared to decrease when fulvestrant was used later in the sequence. Fulvestrant was well tolerated; six patients experienced adverse events (all grade I/II). These data demonstrate that fulvestrant is an effective and well-tolerated therapy for patients with ABC progressing on prior therapies.

Adult↗
PubMed2004

Fulvestrant and the sequential endocrine cascade for advanced breast cancer.

Following relapse on endocrine therapy for advanced, hormone receptor-positive breast cancer, it is common for patients to experience responses to alternative endocrine agents. Fulvestrant ('Faslodex') is a new type of endocrine treatment--an oestrogen receptor (ER) antagonist with no agonist effects. Fulvestrant downregulates cellular levels of the ER resulting in decreased expression of the progesterone receptor. This unique mode of action means that it is important that fulvestrant is placed optimally within the sequence of endocrine therapies to ensure that patients gain maximum benefit. Fulvestrant has shown efficacy when used after progression on tamoxifen or anastrozole in postmenopausal women with advanced breast cancer. After progression on fulvestrant, subsequent endocrine treatments can produce responses in many patients, demonstrating that fulvestrant does not lead to crossresistance with other endocrine therapies. Responses to fulvestrant have also been observed in patients heavily pretreated with prior endocrine therapy. Fulvestrant is a versatile endocrine agent that may be integrated into the therapeutic sequence prior to, or subsequent to, other hormonal therapies, and represents a valuable additional antioestrogen for the treatment of postmenopausal women with advanced breast cancer.

Animals↗
PubMed2006

Regulation of expression of BIK proapoptotic protein in human breast cancer cells: p53-dependent induction of BIK mRNA by fulvestrant and proteasomal degradation of BIK protein.

Induction of mRNA for BIK proapoptotic protein by doxorubicin or gamma-irradiation requires the DNA-binding transcription factor activity of p53. In MCF7 cells, pure antiestrogen fulvestrant also induces BIK mRNA and apoptosis. Here, we provide evidence that, in contrast to doxorubicin or gamma-irradiation, fulvestrant induction of BIK mRNA is not a direct effect of the transcriptional activity of p53, although p53 is necessary for this induction. It is known that p53 up-regulated modulator of apoptosis (PUMA) mRNA is induced directly by the transcriptional activity of p53. Whereas gamma-irradiation induced both BIK and PUMA mRNA, only BIK mRNA was induced by fulvestrant. Whereas both fulvestrant and doxorubicin induced BIK mRNA, only doxorubicin enhanced the DNA-binding activity of p53 and induced PUMA mRNA. Small interfering RNA (siRNA) suppression of p53 expression as well as overexpression of dominant-negative p53 effectively inhibited the fulvestrant induction of BIK mRNA, protein, and apoptosis. Transcriptional activity of a 2-kb BIK promoter, which contained an incomplete p53-binding sequence, was not affected by fulvestrant when tested by reporter assay. Fulvestrant neither affected the stability of the BIK mRNA transcripts. Interestingly, other human breast cancer cells, such as ZR75-1, constitutively expressed BIK mRNA even without fulvestrant. In these cells, however, BIK protein seemed to be rapidly degraded by proteasome, and siRNA suppression of BIK in ZR75-1 cells inhibited apoptosis induced by MG132 proteasome inhibitor. These results suggest that expression of BIK in human breast cancer cells is regulated at the mRNA level by a mechanism involving a nontranscriptional activity of p53 and by proteasomal degradation of BIK protein.

Antineoplastic Agents↗