Clinical Trials

Numerous clinical trials evaluate the therapeutic application of leflunomide across Phase 1 through Phase 4 interventions for various inflammatory, autoimmune, and oncological conditions. Key indications investigated by academic medical centers, research hospitals, and pharmaceutical sponsors include active rheumatoid arthritis, lupus nephritis, chronic graft-versus-host disease, COVID-19, and neuroendocrine tumors harboring MEN1 gene mutations. Across this portfolio, recruitment statuses encompass active recruiting, completed, active not recruiting, and terminated phases.

NCT Number Recruitment Conditions Sponsor/Collaborators Start Date Phases
NCT07709013 RECRUITING
Hematologic Malignancies
Tata Memorial Centre
 2024-10-18 PHASE2
NCT02714634 RECRUITING
Rheumatoid Arthritis; Insufficient Response to Methotrexate or Leflunomide
University Hospital, Strasbourg, France
 2016-03-30 PHASE4
NCT03414502 RECRUITING
Rheumatoid Arthritis
University of Nebraska
 2007-12-10 PHASE3
NCT07138898 RECRUITING
Rheumatic Disease
NYU Langone Health
 2025-12-12 PHASE2
NCT04542733 ACTIVE_NOT_RECRUITING
Kidney Transplant Infection; BK Virus Infection
King Chulalongkorn Memorial Hospital
 2023-06-15
NCT06923488 RECRUITING
Myelodysplastic Syndromes
West Virginia University
 2025-07-15 PHASE1; PHASE2
NCT04997993 RECRUITING
PTEN-Altered Advanced Solid Tumors and HER2 Negative Breast Cancer
Deborah Doroshow
 2023-12-13 PHASE1
NCT05937880 RECRUITING
Henoch-Schonlein Purpura
Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
 2023-01-01
NCT04212416 ACTIVE_NOT_RECRUITING
Chronic Graft Versus Host Disease; Steroid Refractory Graft Versus Host Disease
City of Hope Medical Center
 2020-05-12 PHASE1
NCT04508790 RECRUITING
Recurrent Plasma Cell Myeloma; Refractory Plasma Cell Myeloma
City of Hope Medical Center
 2020-11-24 PHASE2
NCT05014646 ACTIVE_NOT_RECRUITING
Smoldering Plasma Cell Myeloma
City of Hope Medical Center
 2022-03-07 PHASE2
NCT05443425 RECRUITING
Acute Graft Versus Host Disease; Hematopoietic and Lymphoid System Neoplasm
City of Hope Medical Center
 2023-06-16 PHASE1
NCT05937191 RECRUITING
Idiopathic Pulmonary Hemosiderosis; Leflunomide
Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
 2023-06-01 PHASE1; PHASE2
NCT06454383 RECRUITING
Advanced Pancreatic Adenocarcinoma; Stage III Pancreatic Cancer AJCC v8; Stage IV Pancreatic Cancer AJCC v8; Unresectable Pancreatic Ductal Adenocarcinoma
City of Hope Medical Center
 2024-05-13 PHASE1
NCT04370483 ACTIVE_NOT_RECRUITING
Smoldering Plasma Cell Myeloma
City of Hope Medical Center
 2020-10-08 EARLY_PHASE1
NCT06229340 RECRUITING
RAS Mutation; Ras (Kras or Nras) Gene Mutation; Colorectal Cancer Recurrent; Pancreas Cancer; Lung Cancer; Melanoma; Refractory Cancer
N.N. Petrov National Medical Research Center of Oncology
 2023-10-03 PHASE2
NCT05789030 RECRUITING
Autoimmune Diseases
Peking Union Medical College Hospital
 2022-07-01
NCT05605587 TERMINATED
MEN1 Gene Mutation
University Hospital, Basel, Switzerland
 2023-05-02
NCT07428551 COMPLETED
Juvenile Idiopathic Arthritis; Polyarticular Juvenile Idiopathic Arthritis; Refractory Polyarticular Juvenile Idiopathic Arthritis
Bangladesh Medical University
 2024-03-01 PHASE4
NCT03709446 COMPLETED
Breast Neoplasms; Breast Diseases; Metastatic Triple Negative Breast Cancer
Joseph Sparano
 2019-04-16 PHASE1; PHASE2
NCT05626348 RECRUITING
Arthritis, Rheumatoid
Qilu Hospital of Shandong University
 2021-12-22 PHASE4
NCT05113004 RECRUITING
Primary Sjögren's Syndrome (pSS)
Assistance Publique - Hôpitaux de Paris
 2022-01-20 PHASE2
NCT05789017 UNKNOWN
Autoimmune Diseases
Peking Union Medical College Hospital
 2022-07-01
NCT06540937 UNKNOWN
Neuroendocrine Tumors
Cancer Institute and Hospital, Chinese Academy of Medical Sciences
 2020-07-01 PHASE2
NCT04737343 UNKNOWN
ANCA Associated Vasculitis; Maintenance Therapy
Chinese SLE Treatment And Research Group
 2021-06-30
NCT03739853 COMPLETED
Psoriatic Arthritis
University of Oxford
 2019-05-14 PHASE4
NCT04610476 UNKNOWN
Psoriatic Arthritis; Withdrawal; Reduction
University of Erlangen-Nürnberg Medical School
 2020-10-19 PHASE3
NCT04932564 TERMINATED
Musculoskeletal Disease Other; GVHD, Chronic
Tata Memorial Centre
 2023-09-18 PHASE2
NCT06228443 UNKNOWN
Healthy Volunteer
International Bio service
 2024-04-01 PHASE1
NCT05605587 Recruiting
MEN1 Gene Mutation
University Hospital Basel Switzerland
 2023-05-02 Not Applicable
NCT03576794 UNKNOWN
Polymyalgia Rheumatica
Elisabeth Brouwer
 2019-03-01 PHASE3
NCT03649061 COMPLETED
Arthritis, Rheumatoid
P. Verschueren
 2018-06-08 PHASE4
NCT05007678 COMPLETED
COVID-19
Ashford and St. Peter's Hospitals NHS Trust
 2020-09-16 PHASE3
NCT02981979 COMPLETED
Takayasu Arteritis
Jiang lindi
 2016-12-22
NCT04020328 UNKNOWN
Glomerulonephritis, IGA; Renal Insufficiency, Chronic
Shenzhen Second People's Hospital
 2019-09-12 PHASE4
NCT04361214 TERMINATED
COVID-19
University of Chicago
 2020-05-05 PHASE1
NCT01727193 COMPLETED
Myasthenia Gravis
First Affiliated Hospital, Sun Yat-Sen University
 2012-09 PHASE3
NCT04532372 COMPLETED
Hematopoietic and Lymphoid Cell Neoplasm; Malignant Solid Neoplasm; Symptomatic COVID-19 Infection Laboratory-Confirmed
City of Hope Medical Center
 2021-01-07 PHASE1; PHASE2
NCT04463615 COMPLETED
Recurrent Lymphoproliferative Disorder; Refractory Lymphoproliferative Disorder
City of Hope Medical Center
 2021-05-05 PHASE2
NCT03952832 WITHDRAWN
Smoldering Plasma Cell Myeloma
City of Hope Medical Center
 2019-12-11 PHASE2
NCT03715699 UNKNOWN
Autoimmune Disease
Peking Union Medical College Hospital
 2018-07-01
NCT03797872 COMPLETED
Psoriatic Arthritis
University of Oxford
 2019-04-17 PHASE4
NCT02532777 UNKNOWN
Henoch-Schoenlein Purpura Nephritis
Nanjing Children's Hospital
 2015-08 PHASE2
NCT04212416 Active not recruiting
Chronic Graft Versus Host Disease|Steroid Refractory Graft Versus Host Disease
City of Hope Medical Center|National Cancer Institute (NCI)
 2020-05-12 Phase 1
NCT04361214 Terminated
COVID-19
University of Chicago
 2020-05-05 Phase 1
NCT02878161 UNKNOWN
Rheumatoid Arthritis
Fen Li
 2016-01 PHASE4
NCT03449758 COMPLETED
Rheumatoid Arthritis
Sanofi
 2018-03-05 PHASE4
NCT02703194 COMPLETED
Immunoglobulin G4 Related Sclerosing Disease
Chinese PLA General Hospital
 2016-03 PHASE4
NCT02509052 COMPLETED
Recurrent Plasma Cell Myeloma; Refractory Plasma Cell Myeloma
City of Hope Medical Center
 2015-12-02 PHASE1; PHASE2
NCT02930343 TERMINATED
Rheumatoid Arthritis
Jawaharlal Institute of Postgraduate Medical Education & Research
 2016-09 PHASE3
NCT03715699 Unknown status
Autoimmune Disease
Peking Union Medical College Hospital
 2018-07-01 Not Applicable
NCT01620268 TERMINATED
Viruria; Viremia
Changzheng-Cinkate
 2012-07 PHASE2
NCT01172002 UNKNOWN
Nephritis; Lupus
RenJi Hospital
 2010-03
NCT02451748 COMPLETED
Rheumatoid Arthritis
University of Illinois at Chicago
 2015-08 PHASE4
NCT03599986 Completed
Active Rheumatoid Arthritis
Eva Pharma|DataClin
 2017-06-16 --
NCT02644499 COMPLETED
Rheumatoid Arthritis
Jawaharlal Institute of Postgraduate Medical Education & Research
 2015-12-31 PHASE4
NCT02373202 COMPLETED
Rheumatoid Arthritis
Sanofi
 2015-02 PHASE3
NCT01941095 COMPLETED
Rheumatoid Arthritis
Hoffmann-La Roche
 2013-11-20 PHASE3
NCT02275299 UNKNOWN
Rheumatoid Arthritis
Jiangsu Simcere Pharmaceutical Co., Ltd.
 2013-09 PHASE4
NCT01172639 COMPLETED
Rheumatoid Arthritis
P. Verschueren
 2009-02 PHASE4
NCT01709578 COMPLETED
Rheumatoid Arthritis
Sanofi
 2012-10 PHASE3
NCT02057250 COMPLETED
RA
Sanofi
 2014-03 PHASE3
NCT01244958 COMPLETED
Rheumatoid Arthritis
Frank Behrens
 2010-08 PHASE3
NCT01619176 COMPLETED
Rheumatoid Arthritis
Chinese Academy of Sciences
 2012-10
NCT01768572 COMPLETED
Rheumatoid Arthritis
Sanofi
 2013-03 PHASE3
NCT01749787 COMPLETED
Arthritis, Rheumatoid
Protalex, Inc.
 2012-11 PHASE1
NCT02024334 UNKNOWN
Juvenile Idiopathic Arthritis
Mashhad University of Medical Sciences
 2013-06 PHASE4
NCT01774877 COMPLETED
Rheumatoid Arthritis
The First Affiliated Hospital of Anhui University of Traditional Chinese Medicine
 2013-07
NCT01611675 TERMINATED
Melanoma
Massachusetts General Hospital
 2012-07 PHASE1
NCT01617590 UNKNOWN
Rheumatoid Arthritis
Shanxi Medical University
 2012-05
NCT01342016 TERMINATED
Lupus Nephritis
Astellas Pharma Inc
 2011-04 PHASE3
NCT01659242 TERMINATED
Rheumatoid Arthritis
Singapore General Hospital
 2012-07 PHASE4
NCT01225393 COMPLETED
Rheumatoid Arthritis
Genentech, Inc.
 2010-11 PHASE2
NCT00579878 COMPLETED
Rheumatoid Arthritis
University of Nebraska
 2001-03-27 PHASE3
NCT00476996 TERMINATED
Rheumatoid Arthritis
Genentech, Inc.
 2007-05-15 PHASE3
NCT00596206 COMPLETED
Arthritis, Rheumatoid
Sanofi
 2007-12 PHASE3
NCT00684372 UNKNOWN
Terminal Renal Failure; BK Virus Infection
Karolinska University Hospital
 2007-05
NCT00422227 COMPLETED
Rheumatoid Arthritis
Wyeth is now a wholly owned subsidiary of Pfizer
 2007-06 PHASE4
NCT00101374 COMPLETED
HIV Infections
National Institute of Allergy and Infectious Diseases (NIAID)
 2005-01-05 PHASE1
NCT00004071 COMPLETED
Prostate Cancer
Pfizer
 1999-08 PHASE2; PHASE3
NCT00003775 COMPLETED
Brain and Central Nervous System Tumors
Pfizer
 1998-12 PHASE2
NCT00653003 COMPLETED
To Determine Bioequivalence Under Fed Conditions
Par Pharmaceutical, Inc.
 2003-12 PHASE1
NCT00652665 COMPLETED
To Determine the Bioequivalence Study Under Fasting
Par Pharmaceutical, Inc.
 2003-06 PHASE1
NCT00946686 COMPLETED
Rheumatoid Arthritis; Psoriatic Arthritis
Sandoz
 2002-09 PHASE1
NCT00834418 COMPLETED
Healthy
Teva Pharmaceuticals USA
 2002-06 PHASE1
NCT00834405 COMPLETED
Healthy
Teva Pharmaceuticals USA
 2002-04 PHASE1
NCT00003293 COMPLETED
Brain and Central Nervous System Tumors
Pfizer
 1998-02 PHASE3
NCT00268567 COMPLETED
Nephritis, Lupus
Peking University
 2002-10 PHASE2; PHASE3
NCT00280644 COMPLETED
Arthritis, Rheumatoid
Sanofi
 2004-04 PHASE4
NCT00451971 COMPLETED
Arthritis, Rheumatoid
Sanofi
 2002-03 PHASE4
NCT00563849 COMPLETED
Rheumatoid Arthritis
Sanofi
 2003-05 PHASE4
NCT00637819 COMPLETED
Systemic Lupus Eythematosus (SLE)
Sanofi
 2003-01 PHASE2
NCT00802243 UNKNOWN
Bullous Pemphigoid
University Hospital, Limoges
 2007-09 PHASE2
NCT00230035 WITHDRAWN
Systemic Lupus Erythematosus
National Institute of Allergy and Infectious Diseases (NIAID)
 2005-09 PHASE2
NCT00001863 COMPLETED
Uveitis
National Eye Institute (NEI)
 1999-03 PHASE2

(data from https://clinicaltrials.gov, updated on 2026-07-16)

Check the Leflunomide product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Compliance for Clinical Use

Mechanism and Biochemical Profile

Leflunomide acts through its active metabolite A77 1726 to inhibit dihydroorotate dehydrogenase, which disrupts de novo pyrimidine biosynthesis and suppresses rapidly expanding immune cell populations. By inhibiting lymphocyte proliferation, the compound dampens systemic autoimmune activity, thereby alleviating swelling, joint pain, and inflammation in clinical conditions such as active rheumatoid arthritis and graft-versus-host disease.

Appendix RUO and cGMP Quality Standards

Quality Dimension RUO (Research Use Only) cGMP (Current Good Manufacturing Practice)
Clinical Applicability Prohibited in human clinical trials or medical diagnostics. Mandatory for human clinical trials (Phase I–III) and therapies.
Regulatory Status Non-regulated grade; exempt from drug manufacturing laws. Legally enforced by health authorities (e.g., FDA, EMA, NMPA).
Facility Environment Unclassified analytical or research laboratories. Validated Cleanrooms (ISO Class 5–8) with continuous monitoring.
Quality Control Basic purity and activity testing. Rigorous safety release testing (Sterility, Endotoxin, Mycoplasma).
Process Validation Basic equipment calibration; no process validation required. Full qualification (IQ/OQ/PQ) and complete batch records.
Quality Assurance Vendor self-declared without required formal QMS. Mandatory QA/QC unit, Change Control, CAPA, and vendor audits.
Regulatory Impact High risk of IND rejection if used as a critical raw material. Required for IND/NDA filings, supported by Drug Master Files (DMF).

Footnotes

Regulatory Note: Governed by FDA (21 CFR Parts 210/211/312), EMA (EudraLex Vol 4), ICH Guidelines (E6/Q7/Q9/Q10), and compendial standards (USP <71>/<85>/<1043>).

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Note: Technical data last updated: Sep 1, 2026.