Anastrozole is a third-generation non-steroidal selective aromatase inhibitor primarily used for the treatment of hormone-sensitive breast cancer in postmenopausal women. Aromatase is an enzyme responsible for the conversion of androgen (male hormone) into estrogen (female hormone) in various tissues, including gonads and adipocytes. By suppressing the production of estrogen levels in the body, it slows down tumor growth and reduces the progression of hormone-sensitive cancer.

Anastrozole was approved by the FDA under the brand name Arimidex for breast cancer treatment in postmenopausal women. Currently, it is being searched to further explore its effect on breast cancer and ovarian cancer. At Element Sarms, we offer anastrozole purchase exclusively for research purposes.

From Pubchem

IUPAC Name:2-[3-(2-cyanopropan-2-yl)-5-(1,2,4-triazol-1-ylmethyl)phenyl]-2-methylpropanenitrile
Synonym: Arimidex, Anastrole, ICI D1033
Molecular Formula: C17H19N5
Molecular Weight: 293.4 g/mol
CAS Number: 120511-73-1
PubChem CID: 2187

1. Anastrozole and Breast Cancer Prevention

Breast cancer is the most common cancer among women worldwide. Estrogen plays a key role in its pathogenesis and its decreased exposure can reduce the risk of breast cancer. IBIS (International Breast Cancer Prevention) II study was conducted to check the safety and efficacy of anastrozole for the prevention of breast cancer. Postmenopausal women aged 40-70 years were recruited from 153 centers in 18 countries who were at high risk of breast cancer. The subjects were randomized to receive either 1 mg anastrozole or placebo for 5 years.

The results found that 2% of women in the treatment group and 4% in the placebo group developed breast cancer. Anastrozole reduced the frequency of invasive estrogen-receptor-positive breast cancer and ductal carcinoma in situ by 50%. Furthermore, the drug was found to be more effective in preventing high-grade tumors than low-grade tumors. The frequency of other cancers was higher in the placebo group than in the control group [1].

Blinded follow-up for long-term results of IBIS II revealed that the reduction of cancer was larger in the first five years but was still significant after 5 years. The treatment group observed a 54% and 59% reduction in invasive estrogen-positive receptor breast cancer and ductal carcinoma in situ respectively [2].

2. Anastrozole and Breast Cancer Recurrence

A double-blind randomized placebo-controlled IBIS-II DCIS trial was conducted to compare the efficacy of anastrozole and tamoxifen for preventing cancer recurrence in postmenopausal women. Subjects who had been diagnosed with locally excised hormone-receptor-positive DCIS were randomized to receive 1mg anastrozole or 20mg tamoxifen for 5 years. The results didn’t find any significant difference in the recurrent rates between anastrozole (67) and tamoxifen (77) [3].

3. Anastrozole and Early-Stage Breast Cancer

RAnastrozole is commonly used in the treatment of early-stage hormone receptor-positive (HR-positive) breast cancer. Early-stage breast cancer refers to cancer that is localized and has not spread beyond the breast or nearby lymph nodes. Arimidex, Tamoxifen, alone or in combination (ATAC) trial was designed to compare the safety and efficacy of tamoxifen (20mg) and anastrozole (1mg) in postmenopausal women. The results found superior efficacy of anastrozole over tamoxifen as initial adjuvant therapy (post-surgery) for women with early-stage breast cancer.

In postmenopausal women, a 5-year course of tamoxifen treatment is followed by surgery. One study was conducted to assess the benefit of switching to anastrozole after 2 years of tamoxifen treatment as compared to tamoxifen treatment for five years. The results found that treatment with anastrozole resulted in a greater reduction in disease recurrence as compared to 5-year tamoxifen treatment [4].

4. Anastrozole and Advanced Breast Cancer

Anastrozole exerts beneficial effects on advanced breast cancer (ABC). One study compared the safety and efficacy of anastrozole and tamoxifen as a first-line therapy for ABC in postmenopausal women. 353 patients were randomized to receive 1mg anastrozole and 20mg tamoxifen. The results found that anastrozole met the criteria for being as effective as tamoxifen. It also led to a longer time to progression and a lower incidence of thromboembolic events and vaginal bleeding issues. This suggests anastrozole could be a preferred initial treatment for advanced breast cancer in postmenopausal women [5].

5. Anastrozole and Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) involves narrowed lung arteries and right heart strain. Studies suggest that PAH is associated with the female sex and genetic polymorphism in the promoter region of aromatase increases the risk for disease. In a randomized, double-blind, placebo-controlled study, 18 patients with PAH were either given 1 mg anastrozole or placebo. The results found that the treatment group observed a decrease in estrogen levels and improvement in the six-minute walk distance as compared to the control group [6].

6. Current Status of Anastrozole

Anastrozole, an aromatase inhibitor, is an FDA-approved drug for hormone-sensitive breast cancer in postmenopausal women. It is used for the treatment of early-stage and advanced breast cancer and the prevention of breast cancer in women who are at high risk. Currently, many studies are ongoing to compare its efficacy with other anticancer drugs for the treatment of HER-2-positive breast cancer. At Element Sarms, the option to buy liquid anastrozole is exclusively available for research and educational purchase. Only buy Arimidex if you are a qualified researcher.

1. Cuzick, J., et al., Anastrozole for prevention of breast cancer in high-risk postmenopausal women (IBIS-II): an international, double-blind, randomised placebo-controlled trial. The Lancet, 2014. 383(9922): p. 1041-1048
2. Cuzick, J., et al., Use of anastrozole for breast cancer prevention (IBIS-II): long-term results of a randomised controlled trial. The Lancet, 2020. 395(10218): p. 117-122.
3. Forbes, J.F., et al., Anastrozole versus tamoxifen for the prevention of locoregional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in situ (IBIS-II DCIS): a double-blind, randomised controlled trial. Lancet, 2016. 387(10021): p. 866-73.
4. Kaufmann, M., et al., Improved Overall Survival in Postmenopausal Women With Early Breast Cancer After Anastrozole Initiated After Treatment With Tamoxifen Compared With Continued Tamoxifen: The ARNO 95 Study. Journal of Clinical Oncology, 2007. 25(19): p. 2664-2670.
5. PNabholtz, J.M., et al., Anastrozole Is Superior to Tamoxifen as First-Line Therapy for Advanced Breast Cancer in Postmenopausal Women: Results of a North American Multicenter Randomized Trial. Journal of Clinical Oncology, 2000. 18(22): p. 3758-3767.
6. Kawut, S.M., et al., Anastrozole in Pulmonary Arterial Hypertension. A Randomized, Double-Blind, Placebo-controlled Trial. Am J Respir Crit Care Med, 2017. 195(3): p. 360-368.