Maintained by Sreepriya Prasannan

MSc Digital Transformation of Life Sciences (Innopharma Education / Griffith College); MSc & BSc Botany HSE Spark Ignite 2026 — Top 14 finalist

Compiled from ClinicalTrials.gov registry records · Last verified 25 Sep 2026 · Editorial standards

At a glance

Letrozole is named as an intervention in 64 current clinical trials in our China, USA, UK, Ireland and India registers. 36 are recruiting patients now. The most common phase is Phase 3. The sponsor with the most trials is Eli Lilly and Company (7). The most-studied condition is Breast Cancer.

Trials by status

Recruiting3656%
Not yet open35%
Active, closed2336%
By invitation23%

Trials by phase

Phase 32945%
Phase 21523%
Phase 1/2813%
Phase 169%
Phase 2/346%
Phase 412%
Not applicable12%

Clinical trials of Letrozole

64 trials

Study	Phase	Status	Lead sponsor	Registers
Elacestrant for Treating ER+/HER2- Breast Cancer Patients With ctDNA Relapse (TREAT ctDNA) NCT05512364 · ClinicalTrials.gov ↗ · ER-positive Breast Cancer, HER2-negative Breast Cancer, Stage IIB Breast Cancer	Phase 3	Recruiting	European Organisation for Research and Treatment of Cancer - EORTC	Ireland
A Study of Camizestrant in ER+/HER2- Early Breast Cancer After at Least 2 Years of Standard Adjuvant Endocrine Therapy NCT05774951 · ClinicalTrials.gov ↗ · Breast Cancer, Early Breast Cancer	Phase 3	Recruiting	AstraZeneca	UK, USA, India, China
Phase IIIb Study of Ribociclib + ET in Early Breast Cancer NCT05827081 · Early Breast Cancer	Phase 3	Recruiting	Novartis Pharmaceuticals	USA, India, China
A Study of GB491 in Combination With Letrozole in Patients With HR Positive and HER2 Negative Advanced Breast Cancer NCT05851014 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Recruiting	Genor Biopharma Co., Ltd.	China
Efficacy and Safety of Fluzoparib Combined With Adjuvant Endocrine Therapy for HR+/HER2- SNF3-subtype Early Breast Cancer (BCTOP-L-A01) NCT05891093 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Recruiting	Fudan University	China
A Study of Avutometinib (VS-6766) + Defactinib (VS-6063) in Recurrent Low-Grade Serous Ovarian Cancer NCT06072781 · ClinicalTrials.gov ↗ · Low Grade Serous Ovarian Cancer	Phase 3	Recruiting	Verastem, Inc.	Ireland, UK, USA
Saruparib (AZD5305) Plus Camizestrant or Plus Endocrine Therapy, Compared With CDK4/6 Inhibitor Plus Endocrine Therapy or Plus Camizestrant in HR-Positive, HER2-Negative (IHC 0, 1+, 2+/ ISH Non-amplified), BRCA1, BRCA2, or PALB2m Advanced Breast Cancer NCT06380751 · ClinicalTrials.gov ↗ · Advanced Breast Cancer	Phase 3	Recruiting	AstraZeneca	UK, USA, India, China
A Study of Elacestrant Versus Standard Endocrine Therapy in Women and Men With ER+,HER2-, Early Breast Cancer With High Risk of Recurrence NCT06492616 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Recruiting	Stemline Therapeutics, Inc.	UK, USA, China
Phase 3 Study of Gedatolisib as First-Line Treatment for Patients With HR-Positive, HER2-Negative Advanced Breast Cancer (VIKTORIA-2) NCT06757634 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Recruiting	Celcuity Inc	USA, China
A Study Evaluating the Efficacy and Safety of Inavolisib Plus CDK4/6 Inhibitor and Letrozole vs Placebo + CDK4/6i and Letrozole in Participants With Endocrine-Sensitive PIK3CA-Mutated, Hormone Receptor-Positive, HER2-Negative Advanced Breast Cancer NCT06790693 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Recruiting	Hoffmann-La Roche	UK, USA, China
A Phase 3 Study of HRS-8080 Versus Treatment Chosen by Physicians in Locally Advanced and Metastatic Breast Cancer NCT07024173 · ClinicalTrials.gov ↗ · Locally Advanced Breast Cancer, Metastatic Breast Cancer	Phase 3	Recruiting	Shandong Suncadia Medicine Co., Ltd.	China
Palazestrant in Combination With Ribociclib for the First-line Treatment of ER+/HER2- Advanced Breast Cancer NCT07085767 · ClinicalTrials.gov ↗ · Breast Cancer, Locally Advanced Breast Cancer, Metastatic Breast Cancer	Phase 3	Recruiting	Olema Pharmaceuticals, Inc.	UK, USA
A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA) NCT07174336 · Breast Neoplasms, Neoplasm Metastasis	Phase 3	Recruiting	Eli Lilly and Company	Ireland, UK, USA, China
A Phase III Trial Comparing HRS-8080 With Standard Endocrine Therapy in Patients With Intermediate or High Risk Early Breast Cancer NCT07349069 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Recruiting	Shandong Suncadia Medicine Co., Ltd.	China
BGB-43395 Plus Letrozole Versus CDK4/6i Plus Letrozole for Patients With Advanced or Metastatic HR+/HER2- Breast Cancer Who Have Not Received Prior Treatment for Advanced or Metastatic Disease NCT07492641 · ClinicalTrials.gov ↗ · HR+/HER2- Breast Cancer	Phase 3	Recruiting	BeOne Medicines	UK, USA, China
GnRHa + Letrozole in Non-obese Progestin-insensitive Endometrial Cancer and Atypical Hyperplasia Patients NCT05316935 · ClinicalTrials.gov ↗ · Endometrial Neoplasms, Atypical Endometrial Hyperplasia, Progesterone Resistance	Phase 2/3	Recruiting	Xiaojun Chen	China
GnRHa + Letrozole in Obese Progestin-insensitive Endometrial Cancer Patients NCT06379113 · ClinicalTrials.gov ↗ · Endometrial Neoplasms, Atypical Endometrial Hyperplasia, Progesterone Resistance	Phase 2/3	Recruiting	Xiaojun Chen	China
Study of PF-07248144 in Advanced or Metastatic Solid Tumors NCT04606446 · ClinicalTrials.gov ↗ · Locally Advanced or Metastatic ER+ HER2- Breast Cancer, Locally Advanced or Metastatic Castration-resistant Prostate Cancer, Locally Advanced or Metastatic Non-small Cell Lung Cancer	Phase 2	Recruiting	Pfizer	USA, China
Pyrotinib Combined With Trastuzumab, Dalpiciclib, Letrozole Versus TCbHP (Trastuzumab Plus Pertuzumab With Docetaxel and Carboplatin) as Neoadjuvant Treatment in HR +/HER2 + Breast Cancer NCT05638594 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 2	Recruiting	Shengjing Hospital	China
Darsilide Combined With AI, Trastuzumab and Patuzumab in the Neoadjuvant Treatment of HR+/HER2+ Breast Cancer NCT06276868 · ClinicalTrials.gov ↗ · Breast Cancer, HER2-positive Breast Cancer	Phase 2	Recruiting	Henan Cancer Hospital	China
A Study of MK-5684 in People With Certain Solid Tumors (MK-5684-015/OMAHA-015) NCT06979596 · Malignant Neoplasm	Phase 2	Recruiting	Merck Sharp & Dohme LLC	UK, USA
A Study to Test Inavolisib Treatments in Participants With Early-Stage, PIK3CA-Mutated Breast Cancer NCT07054190 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 2	Recruiting	Hoffmann-La Roche	USA
Different Doses of Dalpicicl Combined With Letrozole in the First-line Treatment of HR-positive, HER2-negative Advanced Breast Cancer NCT07285382 · ClinicalTrials.gov ↗ · HR Positive HER2 Negative Advanced Breast Cancer	Phase 2	Recruiting	wanghaibo	China
Dalpiciclib With or Without Entinostat and Letrozole in HR+/HER2- Early Breast Cancer NCT07492394 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 2	Recruiting	Hebei Medical University Fourth Hospital	China
A Study Evaluating the Efficacy and Safety of Multiple Treatment Combinations in Patients With Metastatic or Locally Advanced Breast Cancer NCT03424005 · Metastatic Breast Cancer	Phase 1/2	Recruiting	Hoffmann-La Roche	UK, USA
First-in-Human Study of Tersolisib (STX-478) as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors NCT05768139 · ClinicalTrials.gov ↗ · Breast Cancer, Solid Tumors, Adult	Phase 1/2	Recruiting	Eli Lilly and Company	Ireland, USA
Study of AVZO-021 in Patients With Advanced Solid Tumors NCT05867251 · Advanced Solid Tumor, HR+/HER2- Breast Cancer, HR+, HER2-, Advanced Breast Cancer	Phase 1/2	Recruiting	Avenzo Therapeutics, Inc.	USA
A Trial of HRS-6209 in Combination With Fulvestrant, Letrozole, HRS-8080, or HRS-1358 in Breast Cancer Patients NCT06555068 · ClinicalTrials.gov ↗ · Advanced Unresectable or Metastatic Breast Cancer	Phase 1/2	Recruiting	Jiangsu HengRui Medicine Co., Ltd.	China
ORION-1: Study of AVZO-023 as a Single Agent and in Combination With AVZO-021, and/or Endocrine Therapy in Advanced Solid Tumors NCT06998407 · ClinicalTrials.gov ↗ · HR+/HER2- Breast Cancer, HR+, HER2-, Advanced Breast Cancer	Phase 1/2	Recruiting	Avenzo Therapeutics, Inc.	USA
Study of GVV858 as a Single Agent or in Combination With Endocrine Therapy in Patients With HR+/HER2- Breast Cancer and Other Advanced Solid Tumors NCT07288359 · ClinicalTrials.gov ↗ · Advanced HR+/HER2- Breast Cancer, Advanced CCNE1-amplified Solid Tumors, Metastatic Castration-resistant Prostate Cancer	Phase 1/2	Recruiting	Novartis Pharmaceuticals	USA
A Study of HRS-6208 in Combination With HRS-8080, or Fulvestrant, or Letrozole, With or Without HRS-6209 in Patients With Advanced Unresectable or Metastatic Breast Cancer NCT07389733 · ClinicalTrials.gov ↗ · Advanced Unresectable or Metastatic Breast Cancer of Adults	Phase 1/2	Recruiting	Shandong Suncadia Medicine Co., Ltd.	China
A Study of LOXO-783 in Patients With Breast Cancer/Other Solid Tumors NCT05307705 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 1	Recruiting	Eli Lilly and Company	UK, USA, China
BGB-43395 Alone or as Part of Combination Therapies in Participants With Breast Cancer and Other Advanced Solid Tumors NCT06120283 · ClinicalTrials.gov ↗ · Advanced Solid Tumor, Advanced Breast Cancer, Metastatic Breast Cancer	Phase 1	Recruiting	BeOne Medicines	USA, China
A Study With NKT5097 for Adults With Advanced/Metastatic Solid Tumors NCT07029399 · ClinicalTrials.gov ↗ · HR+ Breast Cancer, Triple Negative Breast Cancer (TNBC), CCNE1 Amplified Advanced Solid Tumors	Phase 1	Recruiting	NiKang Therapeutics, Inc.	USA
Study of IEV407 as Single Agent or in Combination in Patients With Advanced HR+/HER2- Breast Cancer NCT07604571 · ClinicalTrials.gov ↗ · Advanced HR+/HER2- Breast Cancer	Phase 1	Recruiting	Novartis Pharmaceuticals	USA
A Study of Chidamide Plus Endocrine in Maintenance Treatment of HR+/HER2- Breast Cancer After First-line Chemotherapy NCT05890287 · ClinicalTrials.gov ↗ · HR Positive HER2 Negative Advanced Breast Cancer	Not applicable	Recruiting	Tianjin Medical University Cancer Institute and Hospital	China
Study of Dalpiciclib Combined With Letrozole in the Maintenance Treatment of HR Positive and HER2 Negative Metastatic Breast Cancer After First-line Chemotherapy NCT05979220 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 2	Not yet open	Shuangyue Liu	China
Kumorixilib Plus Capecitabine and Letrozole for Neoadjuvant Treatment of HR-Positive HER2-Negative Breast Cancer NCT07691333 · ClinicalTrials.gov ↗ · HR+/HER2- Breast Cancer, Breast Neoplasms	Phase 2	Not yet open	Fujian Cancer Hospital	China
Culmerciclib Combined With Letrozole and Dual HER2 Blockade as Neoadjuvant Therapy for HR+/HER2+ Breast Cancer NCT07795424 · ClinicalTrials.gov ↗ · Breast Cancer, HR Positive, HER2 Positive Breast Cancer	Phase 2	Not yet open	Shengjing Hospital	China
Safety Extension Study for Subjects With HR+, HER2- Breast Cancer for Subjects Who Have Completed the OVELIA Study NCT05645536 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	By invitation	Tolmar Inc.	USA, India
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 NCT06650748 · ClinicalTrials.gov ↗ · Breast Cancer, Early-stage Breast Cancer	Phase 2	By invitation	Peking University	China
Roll-over Study to Allow Continued Access to Ribociclib NCT05161195 · Metastatic Breast Cancer	Phase 4	Active, closed	Novartis Pharmaceuticals	USA, India, China
Hormone Therapy With or Without Combination Chemotherapy in Treating Women Who Have Undergone Surgery for Node-Negative Breast Cancer (The TAILORx Trial) NCT00310180 · ClinicalTrials.gov ↗ · Breast Adenocarcinoma, Hormone Receptor Positive, Stage IA Breast Cancer AJCC v7	Phase 3	Active, closed	National Cancer Institute (NCI)	Ireland
Tamoxifen Citrate, Letrozole, Anastrozole, or Exemestane With or Without Chemotherapy in Treating Patients With Invasive RxPONDER Breast Cancer NCT01272037 · Breast Ductal Carcinoma In Situ, Invasive Breast Carcinoma, Multicentric Breast Carcinoma	Phase 3	Active, closed	National Cancer Institute (NCI)	Ireland
A Study of Nonsteroidal Aromatase Inhibitors Plus Abemaciclib (LY2835219) in Postmenopausal Women With Breast Cancer NCT02246621 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Active, closed	Eli Lilly and Company	UK, USA
A Study of Abemaciclib (LY2835219) in Participants With Breast Cancer NCT02763566 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Active, closed	Eli Lilly and Company	India, China
Letrozole With or Without Paclitaxel and Carboplatin in Treating Patients With Stage II-IV Ovarian, Fallopian Tube, or Primary Peritoneal Cancer NCT04095364 · Low Grade Fallopian Tube Serous Adenocarcinoma, Ovarian Low Grade Serous Adenocarcinoma, Primary Peritoneal Low Grade Serous Adenocarcinoma	Phase 3	Active, closed	NRG Oncology	Ireland
A Study Evaluating the Efficacy and Safety of Giredestrant Combined With Palbociclib Compared With Letrozole Combined With Palbociclib in Participants With Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer (persevERA Breast Cancer) NCT04546009 · Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer	Phase 3	Active, closed	Hoffmann-La Roche	UK, USA, China
Ovarian Suppression Evaluating Subcutaneous Leuprolide Acetate in Breast Cancer NCT04906395 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Active, closed	Tolmar Inc.	USA, India
Phase III Study to Assess AZD9833+ CDK4/6 Inhibitor in HR+/HER2-MBC With Detectable ESR1m Before Progression (SERENA-6) NCT04964934 · ClinicalTrials.gov ↗ · ER-Positive HER2-Negative Breast Cancer	Phase 3	Active, closed	AstraZeneca	UK, USA
A Study of Imlunestrant Versus Standard Endocrine Therapy in Participants With Early Breast Cancer NCT05514054 · Breast Neoplasms	Phase 3	Active, closed	Eli Lilly and Company	Ireland, UK, USA, India, China
Vepdegestrant (ARV-471/PF-07850327) + Palbociclib vs Letrozole + Palbociclib in ER(+)/HER2(-) Advanced Breast Cancer NCT05909397 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Active, closed	Pfizer	USA, China
An Adjuvant Endocrine-based Therapy Study of Camizestrant (AZD9833) in ER+/HER2- Early Breast Cancer (CAMBRIA-2) NCT05952557 · Breast Cancer, Early Breast Cancer	Phase 3	Active, closed	AstraZeneca	Ireland, UK, USA, India, China
OP-1250 (Palazestrant) vs. Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer NCT06016738 · ClinicalTrials.gov ↗ · Breast Cancer, Advanced Breast Cancer, Metastatic Breast Cancer	Phase 3	Active, closed	Olema Pharmaceuticals, Inc.	UK, USA
Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic Disease NCT06760637 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 3	Active, closed	Pfizer	Ireland, UK, USA, India, China
Weekly Paclitaxel and Cisplatin to Treat Hormone Receptor Positive and Triple Negative Breast Cancer Patients NCT02221999 · ClinicalTrials.gov ↗ · Tubular Breast Cancer, Mucinous Breast Cancer, Invasive Ductal Breast Cancer	Phase 2/3	Active, closed	RenJi Hospital	China
GnRHa + Letrozole in Obese Progestin-insensitive Endometrial Atypical Hyperplasia Patients NCT06390904 · ClinicalTrials.gov ↗ · Atypical Endometrial Hyperplasia, Progesterone Resistance, Obesity	Phase 2/3	Active, closed	Xiaojun Chen	China
PF-07104091 as a Single Agent and in Combination Therapy NCT04553133 · ClinicalTrials.gov ↗ · Small Cell Lung Cancer, Ovarian Cancer, Breast Cancer	Phase 2	Active, closed	Pfizer	USA, China
A Study Evaluating the Efficacy and Safety of Biomarker-Driven Therapies in Patients With Persistent or Recurrent Rare Epithelial Ovarian Tumors NCT04931342 · ClinicalTrials.gov ↗ · Ovarian Cancer	Phase 2	Active, closed	Hoffmann-La Roche	UK, USA
Study for Participants Continuing From Pfizer-sponsored Palbociclib (a Study Medicine) Studies NCT05226871 · ClinicalTrials.gov ↗ · Breast Cancer, Head and Neck Cancer	Phase 2	Active, closed	Pfizer	USA, China
Sirolimus for Injection (Albumin-bound) in Combination With Endocrine Therapy for HR+/HER2- Advanced/Metastatic Breast Cancer Patients Who Have Failed Standard Therapy NCT06957379 · ClinicalTrials.gov ↗ · HR+/HER2- Advanced/Metastatic Breast Cancer	Phase 2	Active, closed	CSPC ZhongQi Pharmaceutical Technology Co., Ltd.	China
Study of LEE011, BYL719 and Letrozole in Advanced ER+ Breast Cancer NCT01872260 · ClinicalTrials.gov ↗ · Breast Cancer	Phase 1/2	Active, closed	Novartis Pharmaceuticals	UK, USA
A Study of LY2835219 (Abemaciclib) in Combination With Therapies for Breast Cancer That Has Spread NCT02057133 · ClinicalTrials.gov ↗ · Breast Neoplasms	Phase 1	Active, closed	Eli Lilly and Company	USA
To Evaluate the Safety, Tolerability, and Pharmacokinetics of Inavolisib Single Agent in Participants With Solid Tumors and in Combination With Endocrine and Targeted Therapies in Participants With Breast Cancer NCT03006172 · ClinicalTrials.gov ↗ · Breast Cancer, Solid Tumor	Phase 1	Active, closed	Genentech, Inc.	UK, USA

Registers list studies that are recruiting, about to open, active but closed to enrolment, or enrolling by invitation. The UK and USA registers cover industry-sponsored studies only. Trial titles and statuses are copied from the registry as published.

Conditions studied with Letrozole

64 conditions

Breast Cancer27Metastatic Breast Cancer6Breast Neoplasms4HR+/HER2- Breast Cancer4Advanced Breast Cancer3Atypical Endometrial Hyperplasia3Progesterone Resistance3Breast Cancer, Early Breast Cancer2Ovarian Cancer2Locally Advanced Breast Cancer2ER Positive Breast Cancer2Advanced Solid Tumor2

All 64 conditions

Condition (as registered)	Trials
Breast Cancer	27
Metastatic Breast Cancer	6
Breast Neoplasms	4
HR+/HER2- Breast Cancer	4
Advanced Breast Cancer	3
Atypical Endometrial Hyperplasia	3
Progesterone Resistance	3
Breast Cancer, Early Breast Cancer	2
Ovarian Cancer	2
Locally Advanced Breast Cancer	2
ER Positive Breast Cancer	2
Advanced Solid Tumor	2
HR+, HER2-, Advanced Breast Cancer	2
Advanced HR+/HER2- Breast Cancer	2
Endometrial Neoplasms	2
Obesity	2
HR Positive HER2 Negative Advanced Breast Cancer	2
Breast Ductal Carcinoma In Situ	1
Invasive Breast Carcinoma	1
Multicentric Breast Carcinoma	1
Multifocal Breast Carcinoma	1
Neoplasm Metastasis	1
Low Grade Fallopian Tube Serous Adenocarcinoma	1
Ovarian Low Grade Serous Adenocarcinoma	1
Primary Peritoneal Low Grade Serous Adenocarcinoma	1
Stage II Fallopian Tube Cancer AJCC v8	1
ER-positive Breast Cancer	1
HER2-negative Breast Cancer	1
Stage IIB Breast Cancer	1
Stage III Breast Cancer	1
Breast Adenocarcinoma	1
Hormone Receptor Positive	1
Stage IA Breast Cancer AJCC v7	1
Stage IB Breast Cancer AJCC v7	1
Low Grade Serous Ovarian Cancer	1
Solid Tumors, Adult	1
Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer	1
Malignant Neoplasm	1
ER-Positive HER2-Negative Breast Cancer	1
Solid Tumor	1
CCNE1 Amplification	1
Early Breast Cancer	1
Small Cell Lung Cancer	1
HR+ Breast Cancer	1
Triple Negative Breast Cancer (TNBC)	1
CCNE1 Amplified Advanced Solid Tumors	1
HR+ HER2- Breast Cancer	1
Head and Neck Cancer	1
Advanced CCNE1-amplified Solid Tumors	1
Metastatic Castration-resistant Prostate Cancer	1
Locally Advanced or Metastatic ER+ HER2- Breast Cancer	1
Locally Advanced or Metastatic Castration-resistant Prostate Cancer	1
Locally Advanced or Metastatic Non-small Cell Lung Cancer	1
Hormone-receptor-positive Breast Cancer	1
HR Positive, HER2 Positive Breast Cancer	1
HR+/HER2- Advanced/Metastatic Breast Cancer	1
Tubular Breast Cancer	1
Mucinous Breast Cancer	1
Invasive Ductal Breast Cancer	1
Inflammatory Breast Cancer	1
Early-stage Breast Cancer	1
Advanced Unresectable or Metastatic Breast Cancer	1
HER2-positive Breast Cancer	1
Advanced Unresectable or Metastatic Breast Cancer of Adults	1

By country register

Register	Trials	Recruiting
Clinical trials in China	40	24
Clinical trials in USA	39	22
Clinical trials in UK	21	11
Clinical trials in Ireland	10	4
Clinical trials in India	10	3

A trial with sites in more than one country appears in each of those registers.

Related compounds

Questions about Letrozole trials

How many clinical trials are testing Letrozole?

64 current trials in our China, USA, UK, Ireland and India registers name Letrozole as a drug or biological intervention, as of the registry sync on 25 September 2026. Completed and withdrawn studies are not counted.

Are Letrozole trials recruiting patients?

Yes. 36 of the 64 trials are recruiting: 24 with sites in China, 22 with sites in USA, 11 with sites in UK, 4 with sites in Ireland and 3 with sites in India. Eligibility and site contacts are on each trial's record. Only the study team can confirm whether a patient is eligible.

Who sponsors Letrozole clinical trials?

Eli Lilly and Company (7), Pfizer (5), Hoffmann-La Roche (5) and Novartis Pharmaceuticals (5), among 33 lead sponsors in total. The number in brackets is how many trials each organisation leads.

Where does this information come from?

Every trial, status, phase and sponsor on this page is copied from public ClinicalTrials.gov records by a daily sync. Nothing here describes how Letrozole works or whether it is effective, and it is not medical advice.

How this page is built

Everything on this page is copied from public ClinicalTrials.gov registry records — it is not written from memory, and nothing here describes how Letrozole works or whether it is effective. Each trial links to its own record so you can check it yourself.

ClinicalTrials.gov (U.S. National Library of Medicine) ↗ Trial IDs, titles, intervention names and synonyms, phase, overall status, lead sponsor and conditions for every trial on this page

This page is built automatically: a daily sync job reads the registry records behind our country trial registers, collects every trial that lists Letrozole (or a registered synonym) as a drug or biological intervention, and tabulates the registry fields directly. Placebos and generic comparators are excluded. There is no AI drafting and no per-compound editorial pass, and the page has not been clinically reviewed. The “last verified” date above is the timestamp of that sync, not a review date. Our general editorial approach is described in our editorial standards and corrections policy. The ClinicalTrials.gov data on this page was last retrieved on 25 Sep 2026.

Please verify before you rely on this. This page is general information for life-science and pharmaceutical professionals. It is not medical advice, and it has not been reviewed by a clinician — our editorial team holds life-science qualifications, not clinical ones. It is not exhaustive and may not reflect the most recent label change. Always check the official prescribing information (US Prescribing Information or EU SmPC) and speak to your doctor or pharmacist before acting on anything here. Drugs in the same class are not automatically interchangeable, and approvals, brand names and indications differ between the US, the EU/Ireland (EMA/HPRA) and other regions. Spotted an error? Tell us — we correct promptly and log it.

Letrozole clinical trials