What is Lentaron used for?

Lentaron is indicated for Carcinoma of female breast.

What development phase is Lentaron in?

Lentaron is FDA-approved (marketed).

What is the generic name of Lentaron?

FORMESTANE is the generic (nonproprietary) name of Lentaron.

Last reviewed 2026-04-20 · How we verify

Lentaron (FORMESTANE)

FDA-approved active Small molecule Quality 17/100

Formestane (Lentaron) is an aromatase inhibitor marketed for the treatment of carcinoma of the female breast, competing in a class with several off-patent generics including anastrozole, letrozole, and exemestane. Its key strength lies in its mechanism of action, which effectively blocks the aromatase enzyme to reduce estrogen production, a critical factor in breast cancer management. The primary risk is the strong competition from multiple generic alternatives, which may limit Formestane's market share and revenue potential, especially as its key composition patent expires in 2028.

At a glance

Generic name	FORMESTANE
Drug class	formestane
Target	Aromatase
Modality	Small molecule
Therapeutic area	Oncology
Phase	FDA-approved

Approved indications

Carcinoma of female breast

Common side effects

No common side effects on file.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Lentaron CI brief — competitive landscape report
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