Letrozole

Generic Name: Letrozole

Brand Names: Femara, Kisqali Femara Co-pack

Drug Type: Small Molecule

Chemical Formula: C_₁₇H_₁₁N_₅

CAS Number: 112809-51-5

Unique Ingredient Identifier: 7LKK855W8I

Background: Letrozole, or CGS 20267, is an oral non-steroidal type II aromatase inhibitor first described in the literature in 1990. It is a third generation aromatase inhibitor like exemestane and anastrozole, meaning it does not significantly affect cortisol, aldosterone, and thyroxine.

Letrozole was granted FDA approval on 25 July 1997.

Indication: Letrozole is indicated to treat postmenopausal women with hormone receptor (HR) positive early breast cancer, postmenopausal women with early breast cancer who have periviously been treated with tamoxifen, and postmenopausal women with HR+ or unknown advanced breast cancer. Letrozole, given with ribociclib, is indicated to treat pre, peri, and postmenopausal women with HR+ and human epidermal growth factor 2 (HER2) negative advanced or metastatic breast cancer.

Associated Conditions: Advanced Breast Cancer, Anovulatory cycle, Epithelial Ovarian Cancer, HR+, HER2-, Advanced Breast Cancer, Stage I Breast Cancer, Metastatic HR + HER2 - breast cancer

Clinical Trials

NT-NOA - Novel Treatment of Some Men With Non-Obstructive Azoospermia

Phase 1

Recruiting

Conditions: Infertility, Male

Interventions: Drug: Denosumab (Prolia)
Drug: Letrozole (Aromatase Inhibitors)

First Posted Date: 2024-11-26

Last Posted Date: 2025-04-29

Lead Sponsor: Martin Blomberg Jensen

Target Recruit Count: 16

Registration Number: NCT06706414

Locations: 🇩🇰
Division of Translational Endocrinology, Department of Endocrinology and Internal Medicine, Herlev and Gentofte Hospital, Herlev, Denmark

Testing Low Dose Tamoxifen for Invasive Breast Cancer, the (LoTam) Trial

Phase 3

Recruiting

Conditions: Anatomic Stage 0 Breast Cancer AJCC v8
Anatomic Stage 1 Breast Cancer AJCC v8
Anatomic Stage IIA Breast Cancer AJCC v8
Estrogen Receptor-Positive Breast Carcinoma
HER2-Negative Breast Carcinoma

Interventions: Drug: Tamoxifen
Drug: Anastrozole
Procedure: Mammogram
Drug: Letrozole
Drug: Exemestane
Procedure: Magnetic Resonance Imaging
Biological: Dual X-ray Absorptiometry
Procedure: Biospecimen Collection
Other: Questionnaire Administration

First Posted Date: 2024-11-04

Last Posted Date: 2025-04-02

Lead Sponsor: Alliance for Clinical Trials in Oncology

Target Recruit Count: 1156

Registration Number: NCT06671912

Locations: 🇺🇸
Bon Secours Saint Mary's Hospital, Richmond, Virginia, United States
🇺🇸
Keck Medicine of USC Buena Park, Buena Park, California, United States
🇺🇸
Enloe Medical Center, Chico, California, United States

and more 110 locations

Multigene Risk Score Combined With Ki-67 Dynamic Assessment in Stratified Neoadjuvant Endocrine Therapy Treatment With or Without CDK4/6 Inhibitors in HR+/HER2- Breast Cancer

Phase 2

Not yet recruiting

Conditions: Breast Cancer
Early-stage Breast Cancer

Interventions: Drug: Dalpiciclib
Drug: Letrozole

First Posted Date: 2024-10-21

Last Posted Date: 2024-10-26

Lead Sponsor: Peking University

Target Recruit Count: 100

Registration Number: NCT06650748

Locations: 🇨🇳
Beijing Cancer Hospital, Beijing, China

A Precision Medicine Approach (SMMART-ACT) for the Treatment of Patients with Advanced Sarcoma, Prostate, Breast, Ovarian or Pancreatic Cancer

Phase 2

Not yet recruiting

Conditions: Advanced Breast Carcinoma
Advanced Malignant Solid Neoplasm
Advanced Ovarian Carcinoma
Advanced Pancreatic Carcinoma
Advanced Prostate Carcinoma
Advanced Sarcoma
Anatomic Stage III Breast Cancer AJCC V8
Anatomic Stage IV Breast Cancer AJCC V8
Stage III Ovarian Cancer AJCC V8
Stage III Pancreatic Cancer AJCC V8

Interventions: Drug: Abemaciclib
Procedure: Biopsy
Procedure: Biospecimen Collection
Drug: Fulvestrant
Procedure: Bone Scan
Drug: Carboplatin
Drug: Olaparib
Procedure: Echocardiography
Drug: Gemcitabine
Drug: Pemetrexed
Drug: Exemestane
Drug: Letrozole
Drug: Gefitinib
Procedure: Multigated Acquisition Scan
Other: Survey Administration
Drug: Tamoxifen
Drug: Temozolomide
Drug: Paclitaxel
Drug: Osimertinib
Drug: Pegylated Liposomal Doxorubicin Hydrochloride

First Posted Date: 2024-10-08

Last Posted Date: 2025-02-13

Lead Sponsor: OHSU Knight Cancer Institute

Target Recruit Count: 30

Registration Number: NCT06630325

Locations: 🇺🇸
OHSU Knight Cancer Institute, Portland, Oregon, United States

CARE Initiative: Real-world Emulation of the PALOMA-2 Trial

Completed

Conditions: Metastatic Breast Cancer

Interventions: Drug: Palbociclib
Drug: Letrozole

First Posted Date: 2024-09-23

Last Posted Date: 2024-09-23

Lead Sponsor: Aetion, Inc.

Target Recruit Count: 724

Registration Number: NCT06607601

ONO-4578-06:Phase I Study of ONO-4578 and Letrozole Plus CDK4 /6 Inhibitors in Breast Cancer

Phase 1

Active, not recruiting

Conditions: Metastatic Breast Cancer
Hormone Receptor-positive Breast Cancer
HER2-negative Breast Cancer
Recurrent Breast Cancer

Interventions: Drug: ONO-4578
Drug: letrozole
Drug: abemaciclib
Drug: Palbociclib

First Posted Date: 2024-08-26

Last Posted Date: 2024-08-26

Lead Sponsor: Ono Pharmaceutical Co. Ltd

Target Recruit Count: 46

Registration Number: NCT06570031

Locations: 🇯🇵
Saitama Cancer Center, Ina, Saitama, Japan
🇯🇵
Tokyo Medical University Hospital, Shinjuku-ku, Tokyo, Japan
🇯🇵
National Cancer Center Hospital East, Kashiwa-shi, Chiba, Japan

and more 10 locations

Study to Evaluate the Extended Overall Survival (OS) Data From PARSIFAL Study (The PARSIFAL-LONG Study)

Completed

Conditions: Advanced Breast Cancer
Luminal Breast Cancer
Metastatic Breast Cancer
HER2-negative Breast Cancer
ER-positive Breast Cancer

Interventions: Drug: Fulvestrant Injectable Product
Drug: Letrozole 2.5mg
Drug: Palbociclib 125mg

First Posted Date: 2024-07-29

Last Posted Date: 2024-12-13

Lead Sponsor: MedSIR

Target Recruit Count: 419

Registration Number: NCT06525675

Locations: 🇫🇷
Hopital Tenon, Paris, France
🇫🇷
Hospital Europeo Georges Pompidou AP-HP, Paris, France
🇫🇷
Institut Curie, Paris, France

and more 33 locations

Combination Letrozole and Clomiphene Citrate Versus Letrozole Alone

Not Applicable

Recruiting

Conditions: Polycystic Ovary Syndrome

Interventions: Drug: Letrozole 2.5mg

First Posted Date: 2024-07-18

Last Posted Date: 2024-07-18

Lead Sponsor: Egymedicalpedia

Target Recruit Count: 64

Registration Number: NCT06507332

Locations: 🇪🇬
Ain Shams University Hospitals, Cairo, Abbasia, Egypt

Comparison of the Effectiveness of Single-Dose Methotrexate Protocol With Letrozole + Single-Dose Methotrexate in the Medical Treatment of Patients Diagnosed With Ectopic Pregnancy

Not Applicable

Completed

Conditions: Ectopic Pregnancy

Interventions: Drug: Letrozole
Drug: Methotrexate

First Posted Date: 2024-07-16

Last Posted Date: 2024-07-16

Lead Sponsor: Yuzuncu Yıl University

Target Recruit Count: 60

Registration Number: NCT06504082

Locations: 🇹🇷
Yuzuncu Yil University, Van, Tuşba, Turkey

A Study of Elacestrant Versus Standard Endocrine Therapy in Women and Men With ER+,HER2-, Early Breast Cancer With High Risk of Recurrence

Phase 3

Recruiting

Conditions: Breast Cancer

Interventions: Drug: Elacestrant
Drug: Anastrozole
Drug: Letrozole
Drug: Exemestane
Drug: Tamoxifen

First Posted Date: 2024-07-09

Last Posted Date: 2025-05-21

Lead Sponsor: Stemline Therapeutics, Inc.

Target Recruit Count: 4220

Registration Number: NCT06492616

Locations: 🇪🇸
Hospital Beata Maria Ana, Madrid, Spain
🇺🇸
Southern Cancer Center, PC, Daphne, Alabama, United States
🇺🇸
Banner MD Anderson Cancer Center, Gilbert, Arizona, United States

and more 169 locations

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