New Breast Cancer Survival Data From The Intergroup Exemestane Study (IES) Published In The Lancet Today

New data from the Intergroup Exemestane Study (IES),
published in the Lancet today show that, 2 to 3 years after the end of their treatment,
postmenopausal women with oestrogen sensitive early breast cancer who switched to
exemestane (AROMASIN™) after 2 to 3 years of tamoxifen are 15% - 17% more likely to
be alive, compared to patients who remained on tamoxifen for the full five years of therapy.
These data also demonstrated that patients who switched to exemestane are 25% less
likely to have their cancer return than patients who continued on tamoxifen.1


Lead Investigator Professor Charles Coombes, Director of Cancer Medicine, Imperial
College, London explained: "Exemestane, when given after 2-3 years tamoxifen, reduces
the risk of dying by an additional 15-17% in women with endocrine (hormone) responsive
breast cancer, which accounts for 80-85% of all cases in postmenopausal patients. Since
tamoxifen reduces the risk of dying by 31%, by sequencing, we have shown that the
benefit is to nearly half the risk of dying when compared with no endocrine treatment."


The Lancet publication reinforces the strength of the exemestane data and follows NICE's
Final Appraisal Determination (FAD) on hormonal therapies for the adjuvant treatment of
early oestrogen-receptor-positive breast cancer. Exemestane is the only treatment option
recommended by NICE as an alternative to continued tamoxifen for women who have
already received 2-3 years of initial adjuvant tamoxifen therapy.2


It is estimated that 31,000 postmenopausal women are diagnosed with breast cancer
every year in the UK.2 Exemestane works in postmenopausal women where the hormone
oestrogen promotes tumour growth, which occurs in over two thirds of cases.3 Tamoxifen
blocks the effects of oestrogen on cancer cells, whereas exemestane inhibits the body's
production of oestrogen, stopping the supply of oestrogen to the cancer cells.


"Exemestane is now available in the UK to the thousands of postmenopausal women who
have been and will be diagnosed with oestrogen sensitive breast cancer," said Dr Mary
McCormack, Consultant Clinical Oncologist, University College London Hospital. "It is
important that women with the disease who have received tamoxifen for two to three
years, are fully informed of the potential benefits of switching therapy," she continued.


AROMASIN (exemestane) indication


AROMASIN (exemestane) is indicated for the adjuvant treatment of postmenopausal women with
oestrogen receptor positive invasive early breast cancer, following 2 -3 years of initial adjuvant
tamoxifen therapy. It has been licensed for the treatment of advanced breast cancer in patients that
have progressed on anti-oestrogen therapy since 1999.















About the Intergroup Exemestane Study (IES)1


• The IES is a randomised phase III double-blind study in postmenopausal women with
oestrogen sensitive early breast cancer. The study was designed to test whether, switching to
exemestane after 2-3 years of tamoxifen was more effective than continuing tamoxifen therapy
for the remainder of the five years of treatment


• The study enrolled 4,742 patients from 37 countries and 20 co-operative groups

-- Exemestane group = 2,362 patients

-- Tamoxifen group = 2,380 patients


• Average time on tamoxifen prior to switching to exemestane: 28 months

-- Median follow-up of updated efficacy analysis: 55.7 months


• Compared to continuing tamoxifen therapy, switching to exemestane after 2-3 years of
tamoxifen in postmenopausal women with early breast cancer fuelled by oestrogen has been
shown to:

-- improve disease free survival by 24 percent

-- reduce the risk of the breast cancer coming back by 24 percent

-- reduce the risk of cancer occurring in the other breast by 43 percent


• Aromasin® was generally well tolerated across all studies and in the clinical studies, conducted
with Aromasin®, undesirable effects were usually mild to moderate. The withdrawal rate due to
adverse events in studies was 6.3% in patients with early breast cancer receiving adjuvant
treatment with Aromasin® following initial adjuvant tamoxifen therapy.

- The most commonly reported adverse reactions were hot flushes (22%), arthralgia (17%)
and fatigue (17%).

- Fractures occurred in 277 patients; 162 (7%) exemestane-treated patients and 115 (4.9%)
tamoxifen-treated patients (p=0.003). Hip, spine and wrist fracture rates were low. During
adjuvant treatment with Aromasin®, women with osteoporosis or at risk of osteoporosis
should have their bone mineral density formally assessed by bone densitometry at the
commencement of treatment.

- Most adverse reactions can be attributed to the normal pharmacological consequences of
oestrogen deprivation (e.g. hot flushes).


• Lead investigator:

Professor Charles Coombes

Head of Department, Cancer Medicine - Imperial College School of Medicine


Breast cancer facts4


• Breast cancer is the most common cancer in women, around 42,000 women are diagnosed
each year in the UK


• The strongest risk factor for breast cancer is age: the older the woman the higher the risk


• Most cases (around 80%) of breast cancer occur in postmenopausal women - approximately
8,000 women were diagnosed before their menopause in the UK in 2000


Pfizer Oncology


Pfizer is a research-based global pharmaceutical company that discovers, develops, manufactures
and markets leading prescription medicines for humans and animals, and many of the world's bestknown
brands. In 2003, Pfizer acquired Pharmacia, bringing together two of the world's fastest
growing and most innovative companies to become the largest pharmaceutical company in the
world. The combination expanded Pfizer's global pharmaceutical leadership, broadened its product
base and bolstered its research and development capacity. Currently, Pfizer employs over 100,000
people in over 60 countries, has sales in more than 150 countries. pfizeroncology


References


1 Coombes RC, Kilburn LS, Snowdon CF, on behalf of the Intergroup Exemestane Study. Survival
and safety of exemestane versus tamoxifen after 2-3 years' tamoxifen treatment (Intergroup
Exemestane Study): a randomised controlled trial. Lancet 2007; published online Feb
13.DOI:10.1016/S0140-6736(07)60200-1.


2 National Institute of Clinical Excellence, Final Appraisal Determination. Hormonal therapies for the
adjuvant treatment of early oestrogen-receptor-positive breast cancer: nice.uk
Accessed August 2006


3 Health-cares. Hormone therapy for breast cancer, Available
here. Accessed August 2006


4 Breast Cancer Care. Statistics and facts about breast cancer, Available
here. Accessed August 2006


View drug information on Aromasin Tablets.