Fulvestrant (Faslodex) in advanced breast cancer: clinical experience from a Belgian cooperative study

Promising Therapeutic Impact of a Selective Estrogen Receptor Downregulator, Fulvestrant, as Demonstrated In Vitro upon Low-Grade Serous Ovarian Carcinoma Cell Lines

Few studies have reported hormonal agent use in the treatment of low-grade serous ovarian carcinomas (LGSOCs), which are chemoresistant. Considering the need for novel effective therapies, we investigated the hormone receptor expression and hormonal inhibition efficacy in LGSOCs. Using immunohistochemistry, we assessed the estrogen receptor (ER) expression status in 33 cases of histologically confirmed serous ovarian tumors, including 10, 11, and 12 cases of LGSOCs, serous borderline tumors (SBTs), and serous cystadenomas (SCAs), respectively. The genetic background reported in our previous study was used in the current study. MPSC1 cells, which were established from LGSOCs, were used in cell proliferation assays. We observed a higher ER expression in LGSOCs and SBTs than in SCAs (70%, 81%, and 50%, respectively). Thus, LGSOCs and SBTs exhibit higher ER expression than SCAs. Moreover, the PIK3CA mutation positively correlated with ER expression in LGSOCs (p = 0.0113). MPSC1 cells showed low ER expression on Western blotting. MPSC1 cell proliferation was significantly inhibited by fulvestrant (a selective ER downregulator). The activation of ER and PI3K/AKT signaling pathways may play an important role in LGSOC carcinogenesis. ER downregulation with fulvestrant or combination therapy with PI3K inhibitors is a possible novel treatment for patients with LGSOCs.

Safety of 5α-reductase inhibitors and spironolactone in breast cancer patients receiving endocrine therapies

PURPOSE

To provide dermatologists and oncologists with a foundation for practical understanding and uses of 5α-reductase inhibitors and spironolactone for breast cancer patients and survivors receiving endocrine therapies (ETs), including the effect of these treatments on sex hormone levels, any reported drug interactions, and any risk of malignancy.

METHODS

All published studies from January 1978 through April 2018 were considered, using databases such as PubMed, Google Scholar, and Science Direct. Forty-seven studies were included in this review.

RESULTS

There is no evidence of interactions between 5α-reductase inhibitors and spironolactone with ETs used in breast cancer. Sex hormone alteration with 5α-reductase inhibitor or spironolactone use is variable. Three randomized controlled trials, 1 case-control study, and 6 retrospective cohort studies, including 284 female patients, studied the effects of 5α-reductase inhibitors on serum estrogen levels. Levels were increased in 97 of 284 (34%) patients, decreased in 15 of 284 (5.3%) patients, and unchanged in 162 of 284 (57%) patients. Four retrospective cohort studies, 1 case study, and 1 double-blinded crossover study, including 95 female patients, assessed the effect of spironolactone on estrogen levels. Levels were increased in 25 of 95 (26%) patients, decreased in 6 of 95 (6.3%) patients, and unchanged in 64 of 95 (67%) patients. Ultimately, most patients did not have a significant alteration in the level of estrogen when using 5α-reductase inhibitors or spironolactone. No consistent evidence of increased risk of female breast cancer while on spironolactone was reported in 3 studies including 49,298 patients; the risk of breast cancer with the use of 5α-reductase inhibitors has not been studied.

CONCLUSIONS

Most patients did not show increased estrogen levels with spironolactone and there were no data suggesting increased risk of breast cancer. Based on hormonal and pharmacological activity, spironolactone may be considered for further research on alopecia and hirsutism in breast cancer patients.

Fulvestrant and male breast cancer: a pooled analysis

Male breast cancer is an uncommon malignancy; little is known regarding hormonal manipulations for tamoxifen-resistant male breast cancer patients. This is the first pooled analysis of the literature to synthesize all available data and to evaluate the efficacy and safety of fulvestrant in male breast cancer. This study was performed in accordance with the PRISMA guidelines. All studies that examined the efficacy of fulvestrant in male breast cancer, regardless of sample size, were considered eligible. The search strategy retrieved 31 articles; of these, five articles were eligible (23 patients) for this pooled analysis. The mean age of the study sample was 63.1 years. Adjuvant hormonal treatment was administered in 87.5 % of cases. Fulvestrant was given as first or second line in 40 % of patients, while as third line or beyond in 60 % of patients. 79.0 % of patients at fulvestrant administration had visceral metastases. Regarding best response, in 26.1 % PR was achieved, in 47.8 % of cases SD was recorded, whereas in 26.1 % of patients PD was noted. The median PFS was equal to 5 months. No grade 3 and 4 adverse events were recorded; of note, hot flashes were reported in 18.2 % of male breast cancer patients. Fulvestrant may potentially play a promising role in the optimal therapeutic strategy for male patients with breast cancer diagnosis. However, further clinical and pharmacokinetic investigations are more than warranted before fulvestrant use becomes a common practice in male breast cancer patients.

Toxicity and adverse effects of Tamoxifen and other anti-estrogen drugs

Breast cancer is a heterogeneous disease affecting thousands of people every year. Multiple factors are responsible in causing breast cancer while a number of treatment options are also available for the disease. Tamoxifen is the most widely used anti-estrogen for the treatment of hormone-dependent breast cancer. The specific drug is used as a hormonal therapy for patients who exhibit estrogen receptor positive breast cancer. The pharmacological activity of Tamoxifen is dependent on its conversion to its active metabolite, endoxifen, by CYP2D6. Tamoxifen reduces the risk of recurrence and death from breast cancer when given as adjuvant therapy and provides effective palliation for patients with metastatic breast cancer. In this review we focus on the role of Tamoxifen in breast cancer treatment including mechanisms and side-effects. Finally, we discuss in detail the exciting prospects that lie ahead.

Fulvestrant: a review of its use in the management of hormone receptor-positive metastatic breast cancer in postmenopausal women

Fulvestrant (Faslodex®) is an intramuscularly administered steroidal estrogen receptor antagonist that is devoid of any known estrogen agonist effects. It is indicated as second-line therapy for the treatment of postmenopausal women with hormone receptor-positive advanced breast cancer who have progressed following prior endocrine therapy. In well designed, randomized clinical trials, regimens of fulvestrant 250 and 500 mg provided effective second-line therapy for postmenopausal women with advanced breast cancer who had progressed following prior endocrine therapy. Moreover, fulvestrant 250 mg monthly (with or without a loading dose) was as effective as aromatase inhibitor therapy. However, fulvestrant is absorbed slowly, and greater steady-state concentrations are achieved more rapidly when using a higher dosage with a loading dose regimen. Consequently, a regimen of fulvestrant 500 mg monthly with a loading dose was significantly more effective than a regimen of 250 mg monthly in postmenopausal women with disease progression. Limited data also indicate a potential role for the fulvestrant 500 mg regimen as first-line therapy. Fulvestrant is generally well tolerated with no additional adverse events noted with the high-dose regimen compared with the 250 mg regimens. Furthermore, the incidence of joint disorders was shown to be significantly lower with fulvestrant 250 mg monthly than with anastrozole. Treatment with fulvestrant is not associated with any clinically significant effects on endometrial thickening, bone-specific turnover markers or sex hormone levels. In conclusion, a monthly regimen of intramuscular fulvestrant 500 mg with a loading dose provides effective and well tolerated second-line therapy for postmenopausal women with advanced breast cancer who have progressed following prior endocrine therapy and is now the approved optimal dose.

Activity of fulvestrant in HER2-overexpressing advanced breast cancer

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) overexpression increases the aggressiveness of breast cancer cells resulting in poorer prognosis. Patients with HER2-positive disease are less responsive to endocrine therapies. Trastuzumab monotherapy results in objective responses in only approximately 15% of patients. Fulvestrant retains activity in cells overexpressing HER2 that are resistant to other endocrine treatments. This retrospective study evaluated response to fulvestrant treatment among HER2-positive patients with advanced breast cancer (ABC).

PATIENTS AND METHODS

Clinical experience data from 10 treatment centres were pooled. Postmenopausal patients with predominantly hormone receptor-positive and HER2-positive disease were included. Clinical benefit (CB) was defined as the proportion of patients achieving a response to treatment (partial or complete) or stable disease lasting >/=6 months.

RESULTS

Data for 102 patients were analysed. Fulvestrant resulted in an overall CB rate of 42% (43/101) in HER2-positive patients and 40% (25/63) in patients with visceral disease. Median duration of treatment was 14.5 months (range 6-44 months). Fulvestrant showed activity up to the fourth line of endocrine therapy and up to the seventh line of overall therapy.

CONCLUSIONS

Results indicate that fulvestrant may be a suitable treatment option in extensively pre-treated patients with HER2-positive, hormone receptor-positive ABC. Further exploration of its use in this patient population is warranted.

Fulvestrant in advanced breast cancer following tamoxifen and aromatase inhibition: a single center experience

Fulvestrant is a pure estrogen receptor (ER) antagonist with no agonist effects. We describe the experience of a single center involving 45 postmenopausal women with advanced breast cancer where fulvestrant was utilized following progression on tamoxifen and a third generation aromatase inhibitor. Patients received fulvestrant as first line one (2%), second line 18 (40%), third line 13 (29%), fourth line 10 (22%), and fifth line three (7%) treatment. Median duration of treatment with Fulvestrant was 4 months (range 1-20 months). One patient had a partial response, 14 other (31%) experienced clinical benefit (CB) (defined as response or stable disease for at least 6 months). The median time to progression (TTP) from initiation of fulvestrant was 4 months (range 1-20 months) and the median survival was 10 months (range 1-55 months). In those patients who experienced CB the median TTP was 10 months (range 6-20) and median survival was 21 months (range 7-55). Fulvestrant was well tolerated; two patients experienced side effects severe enough to stop therapy. Despite the fact that fulvestrant was used in the majority of cases, later in the treatment sequence CB was seen in a number of patients. This data suggest fulvestrant is well tolerated and is a useful treatment option in patients with advanced breast cancer who progress on prior endocrine treatment.

Aromatase inhibitors, efficacy and metabolic risk in the treatment of postmenopausal women with early breast cancer

The third-generation aromatase inhibitors (AIs), letrozole, anastrozole and exemestane, are becoming the first choice endocrine drugs for post-menopausal women with breast cancer, since they present greater efficacy when compared with tamoxifen in both adjuvant and metastatic setting. In particular, several large and well designed trials have suggested an important role for AIs in the adjuvant treatment of postmenopausal women with estrogen-receptor positive breast cancer either in the upfront, sequential or extended adjuvant mode. Overall, AIs are associated with a small but significant improvement in disease free survival. The expanding use of AIs in the treatment of early breast cancer means that individual patients will be exposed to the agents for longer durations, making it increasingly important to establish their long-term safety. This review focused on the effects of AIs on bone metabolism, serum lipids and cardiovascular risk. AIs have adverse effects on bone turnover with a reduction of bone mineral density and an increase in the rate of fragility fractures. With respect to tamoxifen AIs present lower thrombotic risk and a less favorable impact on lipid profile, whereas the true effects on cardiovascular risk still remain to be clarified. An adequate monitoring of bone mineral density (BMD) and lipid profile could be recommended for post-menopausal women candidate to AIs.

A phase II study of fulvestrant in the treatment of multiply-recurrent epithelial ovarian cancer

Objective. The goal of treating recurrent ovarian cancer is disease control while minimizing toxicity. Fulvestrant, a novel estrogen receptor (ER) antagonist, has proven clinically beneficial and well-tolerated in treating recurrent breast cancer. Ovarian cancer often expresses ER and may respond to anti-estrogen therapy. We evaluated fulvestrant in women with recurrent ovarian or primary peritoneal cancer. Methods. Patients with ER-positive, multiply recurrent ovarian or primary peritoneal carcinoma and either measurable disease according to RECIST criteria or an abnormal and rising CA-125 were eligible for enrollment. Treatment consisted of single agent fulvestrant, 500 mg IM on Day 1, 250 mg IM on Day 15, and 250 mg IM on Day 29 and every 28 days thereafter until either intolerance or disease progression. Disease response was assessed by monthly physical exams and CA-125 levels as well as CT scans bimonthly. The primary endpoint was clinical benefit (CB=complete response (CR)+partial response (PR)+stable disease (SD)) at 90 days. Results. Thirty-one women were enrolled and 26 women (median age of 61) met inclusion criteria and received at least one dose. Patients had received a median of 5 prior chemotherapeutic regimens (range: 2-13). We observed one CR (4%), one PR (4%), and 9 patients with SD (35%) using modified-Rustin criteria (CA-125 level). Using modified-RECIST criteria 13 patients (50%) achieved SD. The median time to disease progression was 62 days (mean 86 days). Grade 1 toxicity included headache (1 patient) and bromidrosis (2 patients). Conclusions. Fulvestrant is well-tolerated and efficacious. Objective response rates are low, but disease stabilization was common.

The use of fulvestrant, a parenteral endocrine agent, in intestinal obstruction due to metastatic lobular breast carcinoma

Background

The role of fulvestrant in the management of intestinal obstruction associated with lobular carcinoma has not been specifically described.

Case presentation

Herein we present two cases where fulvestrant, as the only available parenteral endocrine agent for postmenopausal advanced breast cancer has the opportunity to provide a means to initiate treatment in those patients who present with varying degrees of intestinal obstruction.

Conclusion

Fulvestrant may obviate the use of chemotherapy while achieving sustained clinical benefit with less toxicity, in appropriately selected patients.