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Exemestane

Hormone Management
AromasinSteroidal AI

Overview

Exemestane is a synthetic steroidal compound classified as an aromatase inhibitor. It is not produced endogenously but is manufactured for therapeutic use. Chemically, it belongs to the class of steroidal aromatase inactivators and is structurally related to the natural substrate androstenedione. Exemestane is primarily used in the management of hormone-responsive breast cancer in postmenopausal women. Researchers have found that it significantly reduces estrogen levels by inhibiting the aromatase enzyme, which is responsible for the conversion of androgens to estrogens. This reduction in estrogen levels is crucial in slowing the growth of estrogen-dependent tumors. The mechanism of action of exemestane involves the irreversible binding to the aromatase enzyme, leading to its inactivation. This process effectively blocks the conversion of androgens into estrogens, thereby reducing circulating estrogen levels. Researchers have observed that this action is beneficial in treating estrogen receptor-positive breast cancer. Exemestane exhibits pharmacokinetic properties characterized by a half-life of approximately 24 hours. It is metabolized primarily in the liver, with its bioavailability affected by first-pass metabolism when administered orally. Researchers have noted that its absorption can be enhanced when taken with food. Clinically, exemestane is used as an adjuvant treatment in postmenopausal women with estrogen receptor-positive breast cancer. It is approved by regulatory agencies such as the FDA and is available by prescription. Researchers have found it to be effective in reducing the risk of cancer recurrence, making it a valuable option in hormone management therapy.

Mechanism of Action

Exemestane acts on the aromatase enzyme, leading to its irreversible inactivation. This action prevents the conversion of androgens to estrogens, resulting in decreased estrogen levels and reduced stimulation of estrogen-dependent tumors.

Molecular Data

FormulaC20H24O2
Molecular Weight296.4 g/mol
CAS Number107868-30-4
PubChem CID60198

Half-Life & Pharmacokinetics

OralApproximately 24 hours

Exemestane is primarily administered orally, and its absorption is enhanced with food.

Storage

Temperature

Store at room temperature (15-30°C)

Light

Protect from light

Form

Stable in tablet form

Notes

Keep in original packaging to protect from moisture.

Solubility

Exemestane is poorly soluble in water but more soluble in organic solvents like ethanol.

Legal Status

🇩🇪DE

Prescription only (verschreibungspflichtig), not a controlled substance under BtMG.

🇺🇸US

FDA approved for prescription use, not a controlled substance.

🇦🇺AU

TGA Schedule 4 (prescription only medicine).

🇬🇧UK

Prescription only medicine (POM) under MHRA regulations.

Legal status information is provided for general reference only and may not reflect the most current regulatory changes. Always verify with official government sources before making any decisions.

7 Research Publications

Human

Clinical cancer research : an official journal of the American Association for Cancer Research · 2020

Researchers observed the effects of two treatments, fulvestrant and exemestane, in patients with hormone receptor-positive metastatic breast cancer who had not responded to previous therapy. The study analyzed samples from patients to better understand the effectiveness of these treatments.

  • Fulvestrant and exemestane were compared in patients who progressed on prior therapy.
  • The study involved analyzing serum and plasma samples from hundreds of patients.
  • The trials aimed to improve treatment options for metastatic breast cancer.
PubMed

Absolute Improvements in Freedom From Distant Recurrence to Tailor Adjuvant Endocrine Therapies for Premenopausal Women: Results From TEXT and SOFT.

Human

Journal of clinical oncology : official journal of the American Society of Clinical Oncology · 2020

Researchers observed that premenopausal women with hormone receptor-positive breast cancer may benefit from treatment with exemestane plus ovarian function suppression, showing a 10% to 15% improvement in avoiding distant recurrence compared to tamoxifen alone. This benefit is more significant for women at high risk of recurrence, while those at low risk see minimal improvements.

  • 91.1% of women had 8-year freedom from distant recurrence overall.
  • Women receiving chemotherapy had a 5.1% improvement with exemestane plus ovarian function suppression.
  • Women at low recurrence risk experienced minimal benefits from escalating therapy compared to tamoxifen alone.
PubMed

Tailoring Adjuvant Endocrine Therapy for Premenopausal Breast Cancer.

Human

The New England journal of medicine · 2018

Researchers found that premenopausal women with breast cancer had lower recurrence rates when treated with the aromatase inhibitor exemestane combined with ovarian suppression compared to those receiving tamoxifen with ovarian suppression. Additionally, the combination of tamoxifen and ovarian suppression improved survival rates compared to tamoxifen alone, although more side effects were reported in the groups receiving ovarian suppression.

  • Exemestane plus ovarian suppression resulted in lower recurrence rates than tamoxifen plus ovarian suppression.
  • Tamoxifen plus ovarian suppression improved survival rates compared to tamoxifen alone.
  • Higher rates of side effects were observed in groups receiving ovarian suppression.
PubMed

Adjuvant exemestane with ovarian suppression in premenopausal breast cancer.

Human

The New England journal of medicine · 2014

Researchers found that premenopausal women with hormone-receptor-positive early breast cancer had better disease-free survival rates when treated with exemestane plus ovarian suppression compared to tamoxifen plus ovarian suppression. Specifically, the 5-year disease-free survival rate was 91.1% for the exemestane group versus 87.3% for the tamoxifen group.

  • Exemestane plus ovarian suppression significantly reduced the risk of cancer recurrence compared to tamoxifen plus ovarian suppression.
  • The 5-year disease-free survival rate was 91.1% for the exemestane group.
  • Overall survival rates were similar between the two treatment groups.
PubMed

Everolimus plus exemestane in postmenopausal patients with HR(+) breast cancer: BOLERO-2 final progression-free survival analysis.

Human

Advances in therapy · 2013

Researchers found that combining everolimus with exemestane significantly extended the time patients with hormone-receptor-positive breast cancer lived without disease progression compared to those taking only exemestane. This benefit was consistent across various patient groups. The study supports the use of this combination treatment for postmenopausal women whose cancer has returned or worsened after previous therapies.

  • Median progression-free survival was 7.8 months for the combination treatment versus 3.2 months for placebo.
  • Results were consistent across different patient subgroups, including those with visceral metastases.
  • The safety profile of the treatment was similar to previous studies.
PubMed

Tamoxifen--what next?

Review

The oncologist · 2004

Researchers observed that while tamoxifen has been a standard treatment for advanced breast cancer in postmenopausal women for over 20 years, newer medications like aromatase inhibitors and fulvestrant may offer better effectiveness and fewer side effects. The study highlights the importance of determining the best treatment sequences to enhance patient care in this evolving field.

  • Aromatase inhibitors show superior efficacy and tolerability compared to tamoxifen.
  • Fulvestrant is effective after tamoxifen failure and has fewer side effects.
  • Sequential use of these newer therapies may prolong treatment options and reduce the need for more toxic chemotherapy.
PubMed

Exemestane.

Review

Drugs · 1999

Researchers found that exemestane, a medication for advanced breast cancer in postmenopausal women, significantly reduces hormone levels and effectively treats the disease. They observed that it offers similar effectiveness to another treatment, megestrol, but with longer-lasting benefits and fewer side effects, such as weight gain.

  • Exemestane reduces hormone levels by 85-95% in patients.
  • It shows an objective response rate of up to 28% in second-line treatment.
  • Exemestane is associated with fewer weight changes compared to megestrol.
PubMed

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This page is for informational and research purposes only. All information is based on published scientific literature. Nothing on this page constitutes medical advice or replaces consultation with a qualified healthcare professional.