Anastrozole is a third-generation non-steroidal aromatase inhibitor. Structurally, it belongs to the triazole and nitrile family. It offers more selectivity as compared to other drugs from the same class without causing any apparent effect on adrenal synthesis. It was first approved by the FDA for the treatment of estrogen receptor-positive breast cancer in 1995. Further, it is being researched for its effect on ovarian cancer and pulmonary arterial hypertension. At Pinnacle Peptides, anastrozole for sale is exclusively available for research and experimentation.

From Pubchem

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

Anastrozole is a class II aromatase inhibitor. Aromatase is an enzyme that facilitates the transformation of androgen into estrogen. Anastrozole mimics androgen and reversibly binds to the heme iron of aromatase, thus blocking the action of the enzyme through competitive inhibition. It reduces E1, E2, and E1S levels in both peripheral and mammary tissues [1].

1. Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is caused by increased blood pressure due to obstruction in the lung arteries. Research suggests that women are more likely to develop pulmonary hypertension than men. Furthermore, single nucleotide polymorphism within the promoter region of aromatase is associated with an increased risk of PAH in patients with cirrhosis.

A randomized double placebo-controlled trial was conducted to check the efficacy of anastrozole in patients with PAH. A total of 18 patients were randomized to receive either 1mg anastrozole or a matching placebo in a 2:1 ratio. The results concluded that the drug reduced E2 levels but didn’t significantly affect tricuspid annular plane systolic excursion (TAPSE). Moreover, the drug was found to be safe and well-tolerated [2].

2. Early-Stage Breast Cancer

Surgery followed by tamoxifen therapy for five years is usually recommended for estrogen receptor-positive early breast cancer. However, the long-term use of tamoxifen is associated with resistance and adverse effects, like thromboembolic events and endometrial cancer.

The ARNO 95 study was designed to evaluate the efficacy of switching to anastrozole after two years of tamoxifen therapy. Patients were randomized to receive either anastrozole 1mg/day after two years of tamoxifen treatment or continue tamoxifen therapy for an additional three years. The participants were monitored every six months for the first three years and annually afterwards. The findings indicated that switching to anastrozole resulted in a significant reduction in recurrence and improved overall survival [3].

3. Advanced Breast Cancer

Literature suggests that anastrozole has superior efficacy as compared to tamoxifen as a treatment of advanced-stage breast cancer in postmenopausal women. In a study, 353 postmenopausal women with advanced breast cancer were randomized to receive either anastrozole 1mg /day or tamoxifen 20mg daily. The findings indicated that anastrozole has equivalent efficacy to tamoxifen. In fact, a significant increase in time to progression and a lower incidence of thromboembolic events and vaginal bleeding were observed in patients who took anastrozole [4].

4. Breast Cancer Prevention

Breast cancer is the most prevalent form of cancer that affects women worldwide. Reduction in the synthesis of estrogen can decrease the risk of breast cancer. The International Breast Cancer Intervention Study (IBIS) was designed to evaluate the safety and efficacy of anastrozole for the prevention of breast cancer. Postmenopausal women who were at high risk of cancer were recruited in this study and were randomized to receive anastrozole (1mg) or placebo for five years. The results found that only 2% of the women who took anastrozole and 4% of the participants in the control group developed breast cancer. Furthermore, anastrozole reduced the occurrence of ductal carcinoma and invasive estrogen receptor-positive breast cancer by 50% [5].

Anastrozole reversibly binds to the aromatase enzyme and blocks the conversion of androgen into estrogen. It is approved by the FDA for the treatment of estrogen receptor-positive breast cancer. Furthermore, it has been shown to be effective in treating pulmonary arterial hypertension. At Pinnacle Peptides, anastrozole purchase is restricted to research and educational purposes. Only buy anastrozole if you are an authorized researcher.

1. Milani, M., G. Jha, and D.A. Potter, Anastrozole Use in Early Stage Breast Cancer of Post-Menopausal Women. Clin Med Ther, 2009. 1: p. 141-156.
2. 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.
3. 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.
4. Nabholtz, 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.
5. 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.