Active Ingredient History
Letrozole (trade name Femara), a nonsteroidal aromatase inhibitor. Femara is indicated for the adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer. Also is indicated for the extended adjuvant treatment of early breast cancer in postmenopausal women, who have received 5 years of adjuvant tamoxifen therapy. Femara has to be used for first-line treatment of postmenopausal women with hormone receptor positive or unknown, locally advanced or metastatic breast cancer and for the treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy. Treatment of breast cancer thought to be hormonally responsive (i.e., estrogen and/or progesterone receptor positive or receptor unknown) has included a variety of efforts to decrease estrogen levels (ovariectomy, adrenalectomy, hypophysectomy) or inhibit estrogen effects (antiestrogens and progestational agents). These interventions lead to decreased tumor mass or delayed progression of tumor growth in some women. In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol. The suppression of estrogen biosynthesis in peripheral tissues and in the cancer tissue itself can therefore be achieved by specifically inhibiting the aromatase enzyme. Letrozole inhibits the conversion of androgens to estrogens. Letrozole selectively inhibits gonadal steroidogenesis but has no significant effect on adrenal mineralocorticoid or glucocorticoid synthesis. Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, resulting in a reduction of estrogen biosynthesis in all tissues. Treatment of women with letrozole significantly lowers serum estrone, estradiol and estrone sulfate and has not been shown to significantly affect adrenal corticosteroid synthesis, aldosterone synthesis, or synthesis of thyroid hormones. Letrozole is rapidly and completely absorbed from the gastrointestinal tract and absorption is not affected by food. Metabolism to a pharmacologically inactive carbinol metabolite (4,4'¬ methanol-bisbenzonitrile) and renal excretion of the glucuronide conjugate of this metabolite is the major pathway of letrozole clearance. In human microsomes with specific CYP isozyme activity, CYP3A4 metabolized letrozole to the carbinol metabolite while CYP2A6 formed both this metabolite and its ketone analog. In human liver microsomes, letrozole strongly inhibited CYP2A6 and moderately inhibited CYP2C19. The most common side effects are sweating, hot flashes, arthralgia (joint pain), and fatigue NCATS
Drug Pricing (per unit)
Note: This drug pricing data is preliminary, incomplete, and may contain errors.
Combination drugs
| Organization | Org Type | FDA approvals | Clinical Trials involvement | Org ID | Force Sort |
|---|
| Organization | Org Type | FDA approvals | Clinical Trials involvement | Org ID | Force Sort |
|---|
Abortion, Induced (Phase 4)
Abortion, Missed (Phase 4)
Abortion, Spontaneous (Phase 4)
Adenocarcinoma of Lung (Phase 1)
Alveolar Bone Loss (Phase 3)
Androgens (Phase 1/Phase 2)
Anovulation (Phase 4)
Arthralgia (Phase 2)
Biomarkers (Phase 2)
Bone Diseases, Metabolic (Phase 4)
Brain Neoplasms (Early Phase 1)
BRCA1 Protein (Phase 3)
Breast Diseases (Phase 2/Phase 3)
Carcinoma, Intraductal, Noninfiltrating (Phase 2)
Carcinoma, Non-Small-Cell Lung (Phase 2)
Carcinoma, Ovarian Epithelial (Phase 3)
Carcinoma, Renal Cell (Phase 1)
Colorectal Neoplasms (Phase 1)
Dermatology (Phase 2/Phase 3)
Diabetes Mellitus, Type 2 (Phase 1/Phase 2)
Drug Evaluation (Phase 2/Phase 3)
Drug Interactions (Early Phase 1)
Drugs, Investigational (Phase 4)
Drug Therapy (Phase 2/Phase 3)
Embryo Implantation (Phase 4)
Endometrial Hyperplasia (Phase 2/Phase 3)
Endometrial Neoplasms (Phase 3)
Endometriosis (Phase 2)
Eunuchism (Phase 4)
Fallopian Tube Neoplasms (Phase 3)
Fertility (Phase 4)
Fertilization in Vitro (Phase 4)
Fibrous Dysplasia, Polyostotic (Phase 1)
Fractures, Bone (Phase 4)
Gestational Trophoblastic Disease (Phase 2/Phase 3)
Gonadotropins (Phase 4)
Growth and Development (Phase 4)
Hamartoma (Phase 3)
Head and Neck Neoplasms (Phase 2)
Healthy Volunteers (Phase 1/Phase 2)
Hepatopulmonary Syndrome (Phase 2)
Hormone Replacement Therapy (Phase 4)
Hormones (Phase 3)
Hypogonadism (Phase 4)
Infertility (Phase 4)
Infertility, Female (Phase 4)
Infertility, Male (Phase 3)
Inflammatory Breast Neoplasms (Phase 2/Phase 3)
Insulin Resistance (Phase 1/Phase 2)
Investigative Techniques (Phase 4)
Leiomyoma (Phase 4)
Leiomyosarcoma (Phase 2)
Letrozole (Phase 4)
Liposarcoma (Phase 1)
Live Birth (Phase 4)
Liver Neoplasms (Phase 2)
Lymphangioleiomyomatosis (Phase 2)
Lymphoma, Non-Hodgkin (Phase 1)
Melanoma (Phase 1)
Menopause (Phase 2)
Mesothelioma (Phase 1)
Metabolic Diseases (Phase 1/Phase 2)
Musculoskeletal Diseases (Phase 2)
Mutation (Phase 3)
Myoma (Phase 4)
Neoadjuvant Therapy (Phase 3)
Neoplasm Metastasis (Phase 4)
Neoplasms ()
Neoplasms, Hormone-Dependent (Phase 3)
Neoplasms, Squamous Cell (Phase 1)
Obesity (Phase 4)
Oligospermia (Phase 3)
Osteoporosis (Phase 4)
Ovarian Cysts (Phase 4)
Ovarian Diseases (Phase 2)
Ovarian Hyperstimulation Syndrome (Phase 4)
Ovarian Neoplasms (Phase 4)
Ovulation (Phase 4)
Ovulation Induction (Phase 4)
Pain (Phase 2)
Pancreatic Neoplasms (Phase 2)
Peritoneal Neoplasms (Phase 3)
Polycystic Ovary Syndrome (Phase 4)
Postmenopause (Phase 4)
Pregnancy (Phase 3)
Pregnancy, Ectopic (Phase 4)
Pregnancy, Tubal (Phase 3)
Progesterone (Phase 2/Phase 3)
Prostatic Neoplasms (Phase 2)
Proto-Oncogene Proteins c-kit (Phase 2)
Puberty, Precocious (Phase 1)
Quality of Life (Phase 2)
Recurrence (Phase 2)
Reproductive Techniques (Phase 4)
Reproductive Techniques, Assisted (Phase 4)
Sarcoma (Phase 2)
Small Cell Lung Carcinoma (Phase 2)
Transsexualism (Phase 3)
Triple Negative Breast Neoplasms (Phase 2)
Uterine Cervical Neoplasms (Phase 2)
Uterine Diseases (Phase 1)
Uterine Neoplasms (Phase 2/Phase 3)
| Trial | Phase | Start Date | Organizations | Indications |
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