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Letrozole 2.5mg (letrozole-2-5mg)

Pfizer Inc. · preclinical active

Letrozole 2.5mg (generic name: letrozole-2-5mg) is a 2.5 mg letrozole per day, administered orally (continuous treatment) drug developed by Pfizer Inc.. It is currently in preclinical development.

2.5 mg letrozole per day, administered orally (continuous treatment)

Letrozole 2.5mg is an aromatase inhibitor approved for hormone receptor-positive breast cancer treatment in postmenopausal women. It works by blocking the enzyme aromatase, which converts other hormones into estrogen in the body. A key clinical differentiator is its potency and favorable tolerability profile compared to other aromatase inhibitors.

Likelihood of approval
8% vs 5% industry baseline
If approved by FDA: likely 2036–2040
Steps remaining: Phase 1 → Phase 2 → Phase 3 → NDA/BLA submission
Confidence: Low
Why this estimate
  • Baseline preclinical → approval rate +5.0pp
    Industry-wide preclinical drugs reach approval ~5% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
  • Big-pharma sponsor +3.0pp
    Pfizer Inc. is a top-20 pharma sponsor — historical approval rates run ~3pp above average due to scale, regulatory experience, and trial-design quality.
Predicted approval windows by jurisdiction (conditional on FDA approval)
Regulator Country Likely year Lag vs FDA
FDA US 2036–2040 —
EMA EU 2037–2041 +0.7 yr
MHRA GB 2037–2041 +0.7 yr
Health Canada CA 2037–2042 +0.9 yr
TGA AU 2037–2042 +1.2 yr
PMDA JP 2037–2042 +1.5 yr
NMPA CN 2038–2043 +2.3 yr
MFDS KR 2037–2042 +1.4 yr
CDSCO IN 2037–2043 +1.8 yr
ANVISA BR 2038–2043 +2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic nameletrozole-2-5mg
SponsorPfizer Inc.
Drug class2.5 mg letrozole per day, administered orally (continuous treatment)
Therapeutic areaOncology
Phasepreclinical

Mechanism of action

Letrozole is a targeted cancer therapy that works by shutting down estrogen production in postmenopausal women. In these women, most estrogen is made through a process involving an enzyme called aromatase, which converts other hormones into estrogen in fatty tissues throughout the body. By blocking this enzyme, letrozole dramatically reduces circulating estrogen levels. Estrogen-dependent breast cancers rely on this hormone to survive and multiply. When letrozole cuts off estrogen supply, cancer cells either stop growing or die. This approach is particularly effective for hormone receptor-positive breast cancers, which have proteins on their surface that bind to estrogen and use it as a growth signal. By removing the fuel source, letrozole essentially puts the brakes on tumor progression. Unlike some older breast cancer treatments that work throughout the whole body indiscriminately, letrozole specifically targets the estrogen-production pathway. This selective mechanism allows it to control cancer while minimizing damage to healthy cells that don't depend on estrogen for survival, though some side effects can still occur due to the body-wide reduction in estrogen levels.

Approved indications

No approved indications tracked.

Pipeline indications

Common side effects

No common side effects on file.

Key clinical trials

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results

Competitive intelligence

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

Frequently asked questions about Letrozole 2.5mg

What is Letrozole 2.5mg?

Letrozole 2.5mg (letrozole-2-5mg) is a 2.5 mg letrozole per day, administered orally (continuous treatment) drug developed by Pfizer Inc..

How does Letrozole 2.5mg work?

2.5 mg letrozole per day, administered orally (continuous treatment)

Who makes Letrozole 2.5mg?

Letrozole 2.5mg is developed by Pfizer Inc. (see full Pfizer Inc. pipeline at /company/pfizer).

What is the generic name of Letrozole 2.5mg?

letrozole-2-5mg is the generic (nonproprietary) name of Letrozole 2.5mg.

What drug class is Letrozole 2.5mg in?

Letrozole 2.5mg belongs to the 2.5 mg letrozole per day, administered orally (continuous treatment) class. See all 2.5 mg letrozole per day, administered orally (continuous treatment) drugs at /class/2-5-mg-letrozole-per-day-administered-orally-continuous-treatment.

What development phase is Letrozole 2.5mg in?

Letrozole 2.5mg is in preclinical.

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