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New Data For Faslodex (Fulvestrant) Demonstrate Efficacy Following Aromatase Inhibitor Therapy: Presented at SABCS

SAN ANTONIO, TX -- December 11, 2004 -- Important new data from two studies presented at the 27th Annual San Antonio Breast Cancer Symposium (SABCS) in the USA, suggest that 'Faslodex' (fulvestrant) is an effective and well tolerated treatment for postmenopausal women with advanced breast cancer who have experienced disease progression on aromatase inhibitor therapy.

The first of the two studies1 was conducted by Dr Lucien Perey, from the Swiss Group for Clinical Cancer Research (SAKK), in Bern, Switzerland. In this phase II trial, 67 postmenopausal women with advanced breast cancer whose disease had progressed after previous treatment with both tamoxifen and then an aromatase inhibitor were assessed. The results showed 28% of patients achieved a clinical benefit (PR+SD>/= 24 weeks*).

This finding is further supported by data from the second study2, conducted by Dr James Ingle, from the Mayo Clinic in Minnesota, USA. In this phase II trial, 77 postmenopausal women with advanced breast cancer whose disease progressed following treatment with an aromatase inhibitor and, at most, one additional hormonal agent, were assessed. These data showed that a similar clinical benefit rate (PR+SD>/= 24 weeks*) was observed in almost one third (29%) of the patients in the trial. These data also showed that 'Faslodex' was well tolerated, with only mild-to-moderate side effects being reported and no patients withdrawing due to adverse events.

"The data from these two studies represent an important finding since they suggest that patients with advanced breast cancer who have progressed on aromatase inhibitor therapy have an additional effective and well tolerated hormonal treatment option at their disposal, which further delays the need to use chemotherapy" commented Dr Perey. "Significantly, what is also key here is the fact that both studies have shown a similar level of efficacy and tolerability for patients who have received prior aromatase inhibitor therapy and who were then treated with 'Faslodex'."

Previous data, which form the basis of its current approved indication, have confirmed that 'Faslodex' is effective and well tolerated in postmenopausal women with advanced breast cancer whose disease has progressed following treatment with tamoxifen3. However, as aromatase inhibitors such as 'Arimidex' (anastrozole) have now demonstrated their superiority over tamoxifen in both the adjuvant setting and as first line therapy for advanced breast cancer, the changing treatment paradigm means that the efficacy and tolerability of 'Faslodex' following aromatase inhibitor therapy has become an important question for clinicians and patients alike. These new data therefore represent an important development that will be eagerly welcomed by the oncology community, since they suggest that women who have received prior non-steroidal aromatase inhibitor therapy now have an additional effective and well-tolerated hormonal therapy with which to fight their disease, extending the benefits of hormonal therapy and delaying the need for the more aggressive chemotherapy.

In order to confirm findings from studies such as these, AstraZeneca are undertaking two large-scale international, randomised controlled trials of 'Faslodex' following aromatase inhibitor therapy, known as the EFECT trial (Evaluation of Fulvestrant versus Exemestane Clinical Trial) and the SOFEA trial (Study of 'Faslodex', Exemestane and 'Arimidex'), both of which are expected to confirm the efficacy and tolerability of 'Faslodex' in this important setting.

The possibility of extending the benefits of 'Faslodex' treatment to all women with advanced disease at the first opportunity is also being explored in more detail. Additional data presented at the SABCS congress have shown efficacy for 'Faslodex' as a first-line therapy for postmenopausal patients with advanced breast cancer. These data come from a study conducted by Professor John Robertson at Nottingham City Hospital in the UK4, which assessed 30 patients with previously untreated advanced breast cancer who received 'Faslodex' as their initial treatment. The results show continued and maintained downregulation of oestrogen receptor levels for a sustained period (six months). Patients treated with 'Faslodex' who had evaluable disease at six months had a clinical benefit rate of 79% (PR+SD>/= 24 weeks*). Importantly, the data from the study also showed that the oestrogen receptor was present at the time of disease progression in all patients, supporting the use of further hormonal therapies following 'Faslodex' treatment. This is significant since it means that the benefits of well-tolerated hormonal therapy may be extended, delaying the need to resort to chemotherapy with its well recognised side effects.

"These data from this phase II trial highlight the potential of Faslodex as an effective first line treatment for postmenopausal women with locally advanced and advanced breast cancer" commented Professor Robertson. "These data add to the increasingly extensive data base which suggest that 'Faslodex' is both a very effective and arguably the best tolerated hormonal therapy available."

'Faslodex' is a novel therapy, the first of a new type, with a unique mode of action. 'Faslodex' has a long duration of response and does not limit subsequent treatment options, therefore extending the benefits of well tolerated hormonal therapy. In clinical trials, 'Faslodex' was well tolerated and was associated with significantly less joint pains (arthralgia) than the aromatase inhibitor anastrazole3 - arthralgia being a side effect associated with the aromatase inhibitor class of drugs. In a separate trial, 'Faslodex' was associated with fewer hot flushes than tamoxifen5.

'Faslodex' is indicated for the treatment of postmenopausal women with receptor-positive locally advanced or metastatic breast cancer, for disease recurrence or progression on or after therapy with an anti-oestrogen such as tamoxifen. It has been launched in the USA since May 2002, and is also now available in Brazil and over 25 countries in Europe.

'Faslodex' is a sustained release formulation that is administered once monthly as an intramuscular injection, which may offer compliance benefits and since it is an hormonal treatment, it does not cause the side effects commonly associated with chemotherapy.

'Faslodex' works differently to other anti-oestrogen agents for breast cancer, in that it binds to the oestrogen receptor in the breast cancer cell, and this interaction results in loss of the cellular oestrogen receptor (down-regulation). 'Faslodex' attacks cancer cells that have grown resistant to current anti-oestrogen treatment options. Thousands of women are diagnosed with advanced breast cancer each year - advanced breast cancer is diagnosed when cancer that is originally confined to the breast is found in other parts of the body. More specifically, a woman is considered to have advanced disease when breast cancer cells also form a tumour in places such as the lungs, liver or bones. In locally advanced disease, the cancer involves spread to the tissues surrounding the breast, such as underlying muscles or skin, but not to distant organs. Extensive lymph node involvement is also counted as locally advanced disease.

References:
1. Perey LR et al. Fulvestrant as hormonal treatment in postmenopausal patients with advanced breast cancer progressing after treatment with tamoxifen and aromatase inhibitors: update of a phase II SAKK trial. SABCS 2004, abs.
2. Ingle JN et al. Evaluation of fulvestrant in women with advanced breast cancer progression on prior aromatase inhibitor therapy: a phase II trial of the North Central Cancer Treatment Group. SABCS 2004, abs.
3. Robertson JFR et al. Fulvestrant versus anastrozole for the treatment of advanced breast carcinoma in postmenopausal women; A prospective combined analysis of two multicentre trials. Cancer 2003; 98: 229-238
4. Robertson JFR et al. Clinical efficacy of fulvestrant and effects on estrogen receptor levels during first-line endocrine treatment of patients with advanced breast cancer. SABCS 2004, abs.
5. A. Howell, et al. Comparison of fulvestrant versus tamoxifen for the treatment of advanced breast cancer in postmenopausal women previously untreated with endocrine therapy: a multinational, double-blind, randomized trial. J Clin Oncol. 2004 May 1;22(9):1605-13.


SOURCE: AstraZeneca

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