Letrozole (and other aromatase inhibitors)
Daily pills that stop the body making oestrogen after menopause, the backbone of hormone therapy for most breast cancers.
Non-steroidal (letrozole, anastrozole) and steroidal (exemestane) aromatase inhibitors block conversion of androgens to oestrogens in fat and tumour tissue. Superior to tamoxifen for postmenopausal women in adjuvant (ATAC, BIG 1-98) and metastatic settings; the standard partner for CDK4/6 inhibitors in first-line metastatic disease. Used with ovarian suppression in premenopausal women (SOFT/TEXT). Arthralgia, bone loss, and vaginal dryness drive non-adherence.
1.Adrenal androgens circulate to fat, muscle, and tumour
- Route
- Oral
- Schedule
- Letrozole 2.5 mg, anastrozole 1 mg, or exemestane 25 mg once daily; 5-10 years adjuvant; until progression metastatic
- Dose modifications
- Rarely needed; switch agent for intolerable arthralgia
- Monitoring
- Bone density every 1-2 years; lipids
Source: www.accessdata.fda.gov/drugsatfda_docs/label/2014/020726s027lbl.pdf. Doses are for orientation; the current label governs.
- Medicare
- Part D (self-administered)
Oral, self-administered, so it is a Part D drug: covered through a stand-alone Part D plan or Medicare Advantage drug benefit, usually on the specialty tier with 25 to 33% coinsurance until the annual cap ($2,000 in 2025, $2,100 in 2026). Letrozole, anastrozole and exemestane are all generic, low-tier Part D drugs.
- Commercial insurance
- covered on label
Multi-source generic on low-cost tiers; usually no prior authorisation. Cash prices without insurance are modest.
Sources: Medicare.gov: Drug coverage (Part D) · Medicare.gov: Costs for Medicare drug coverage (annual out-of-pocket cap). Not medical or financial advice; verify with your plan.
- Appraised for
- Adjuvant hormonal therapy for early oestrogen-receptor-positive breast cancer
- Notes
- Anastrozole, letrozole and exemestane are all generic; NICE NG101 governs use. Anastrozole was licensed for breast cancer prevention in 2023 under the MHRA repurposing programme.
- NHS England
- Routinely funded for the appraised indication (or via managed access)
Sources: NICE TA112 · SMC advice: letrozole and other aromatase inhibitors. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
- 25 Jul 1997ApprovalUS
Letrozole approved for advanced breast cancer
- 28 Dec 2005ApprovalUS
Letrozole adjuvant indication
Approvals
| Region | Year | Indication |
|---|---|---|
| US | 1997 | Advanced breast cancer after tamoxifen (letrozole) |
| US | 2005 | Adjuvant early breast cancer (letrozole) |
| US | 1997 | Advanced breast cancer in postmenopausal women; adjuvant from 2005 |
| Adverse event | Any grade | Grade 3+ |
|---|---|---|
| Arthralgia/myalgia | 35% | — |
| Hot flushes | 33% | — |
| Bone fracture (5-year) | 10% | — |
| Fatigue | 20% | — |
| Arthralgia | 25% | — |
| Bone loss / fracture | — | — |
Cumulative; DEXA monitoring recommended. Events listed without rates were not read from a primary source; see the label. Blank cells mean the figure was not sourced, not that it is zero.
Trials
topRecruiting now (live from ClinicalTrials.gov)
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Landmark trials in OnCo
Latest papers
topQuery for this drug: (TITLE:"Letrozole" OR ABSTRACT:"Letrozole" OR TITLE:"and other aromatase inhibitors" OR ABSTRACT:"and other aromatase inhibitors" OR TITLE:"Femara; anastrozole" OR ABSTRACT:"Femara; anastrozole" OR TITLE:"Arimidex ; exemestane" OR ABSTRACT:"Arimidex ; exemestane" OR TITLE:"Aromasin" OR ABSTRACT:"Aromasin") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Letrozole (and other aromatase inhibitors), not a curated reading list.
Pages like this
not linked directly; found by shared links- ProductExemestane
Shares SOFT & TEXT, Dietitian-led weight-loss programmes in HR-positive breast cancer, Estrogen receptor (ERα), Endocrine therapy (SERMs, AIs, SERDs).
- ProductTamoxifen
Shares Aromatase inhibitor, SOFT & TEXT, Dietitian-led weight-loss programmes in HR-positive breast cancer, Estrogen receptor (ERα).
- ProductGoserelin / leuprolide (ovarian function suppression)
Shares SOFT & TEXT, Estrogen receptor (ERα), Endocrine therapy (SERMs, AIs, SERDs), HR-positive / HER2-negative breast cancer.
- TermHormone receptor status (ER / PR)
Shares Aromatase inhibitor, Estrogen receptor (ERα), Endocrine therapy (SERMs, AIs, SERDs), HR-positive / HER2-negative breast cancer.
- ProductProgestins (megestrol acetate, medroxyprogesterone, levonorgestrel IUD)
Shares Oestrogen receptor signalling, Estrogen receptor (ERα), Endocrine therapy (SERMs, AIs, SERDs), Endometrial cancer.
- TrialBWEL (Breast Cancer Weight Loss, Alliance A011401)
Shares GLP-1 receptor agonists as adjuvant weight-loss therapy in HR-positive breast cancer, Dietitian-led weight-loss programmes in HR-positive breast cancer, Endocrine therapy (SERMs, AIs, SERDs), HR-positive / HER2-negative breast cancer.
- PersonMatthew P. Goetz
Shares MONARCH 3, Estrogen receptor (ERα), HR-positive / HER2-negative breast cancer.
- TermSelective oestrogen receptor degrader (SERD)
Shares Aromatase inhibitor, Estrogen receptor (ERα), Endocrine therapy (SERMs, AIs, SERDs), HR-positive / HER2-negative breast cancer.