AI Article Synopsis
- Letrozole is a competitive aromatase inhibitor, while exemestane is an irreversible aromatase inactivator, leading to different effects on the aromatase enzyme.
- Research shows that exemestane can still be effective after resistance to nonsteroidal aromatase inhibitors like letrozole.
- The NEOLETEXE trial aims to investigate the mechanisms behind this lack of cross-resistance between the two drugs, with ethical approval granted for the study.
Article Abstract
The aromatase inhibitor letrozole (Femar/Femara) and the aromatase inactivator exemestane (Aromasin) differ in their biochemical effect on the aromatase enzyme. Letrozole is a competitive aromatase inhibitor while exemestane binds irreversibly to the aromatase enzyme. This pharmacological difference is of clinical interest since a lack of cross-resistance has been documented. It has been demonstrated in several clinical trials that exemestane may cause a disease regression following resistance to nonsteroidal aromatase inhibitors. The exact mechanism(s) behind this phenomenon is yet unknown. Here, we present the NEOLETEXE trial with the aim of exploring the individual mechanisms involved behind the observed lack of cross resistance. Clinical trial registration: The trial has been approved by the Regional Ethics Committee of South-East Norway (project number 2015/84).
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| http://dx.doi.org/10.2217/fon-2019-0258 | DOI Listing |
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- Aromatase inhibitors like letrozole and exemestane are used to treat estrogen receptor-positive breast cancer in postmenopausal women, sometimes showing effectiveness even after initial treatments fail.
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