Clinical Trials

Numerous clinical trials evaluate flucytosine across infectious disease and oncology indications, primarily focusing on cryptococcal meningitis in HIV patients alongside neuro-oncological conditions such as glioblastoma multiforme, astrocytoma, and recurrent malignant gliomas. Sponsored by diverse pharmaceutical, academic, and government institutions—including Pfizer, Novartis, NIAID, and City of Hope Medical Center—these Phase 1 through Phase 4 investigations reflect varied recruitment statuses ranging from recruiting and completed to terminated or suspended.

NCT Number Recruitment Conditions Sponsor/Collaborators Start Date Phases
NCT06264388 RECRUITING
High Grade Glioma; Anaplastic Astrocytoma
Ashish Shah
 2024-05-01 PHASE2
NCT06666322 RECRUITING
Hiv; Cryptococcal Meningitis
David Boulware
 2025-05-28 PHASE2; PHASE3
NCT06525389 NOT_YET_RECRUITING
Talaromycosis
Duke University
 2026-09-01 PHASE3
NCT04105374 WITHDRAWN
Anaplastic Astrocytoma; Glioblastoma; Oligodendroglioma; Supratentorial Glioblastoma
NRG Oncology
 2020-01-31 PHASE2; PHASE3
NCT06178627 UNKNOWN
Cryptococcal Meningitis; Antifungal Agents
Huashan Hospital
 2023-08-13 PHASE4
NCT06414512 COMPLETED
Cryptococcal Meningitis
University of Minnesota
 2024-04-09 PHASE2
NCT05471063 UNKNOWN
Cryptococcal Meningitis
Peking Union Medical College Hospital
 2022-08-22
NCT03724071 TERMINATED
Colorectal Neoplasm; Digestive System Neoplasm
Transgene
 2018-10-16 PHASE1; PHASE2
NCT04194034 TERMINATED
Colorectal Neoplasms
Transgene
 2020-01-17 PHASE1; PHASE2
NCT04140461 UNKNOWN
Cryptococcal Meningitis; HIV Infections
Shanghai Public Health Clinical Center
 2020-01-02 PHASE3
NCT04089163 WITHDRAWN
Bladder Cancer
Tocagen Inc.
 2019-12 PHASE1
NCT04226066 UNKNOWN
Advanced Malignant Solid Tumors
Tasly Tianjin Biopharmaceutical Co., Ltd.
 2019-11-20 PHASE1; PHASE2
NCT01562626 SUSPENDED
Tumors; Neoplasms; Cancer
Anaeropharma Science, Inc.
 2012-09 PHASE1; PHASE2
NCT04327011 TERMINATED
Glioblastoma Multiforme; Astrocytoma; Gliomas, Malignant
Tocagen Inc.
 2011-02 PHASE1
NCT03294486 UNKNOWN
Glioblastoma; Brain Cancer
Assistance Publique - Hôpitaux de Paris
 2017-10-12 PHASE1; PHASE2
NCT02015819 COMPLETED
Adult Anaplastic Astrocytoma; Adult Anaplastic Oligodendroglioma; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Recurrent Adult Brain Tumor; Anaplastic Oligoastrocytoma
City of Hope Medical Center
 2014-10-07 PHASE1
NCT02136030 UNKNOWN
Cryptococcal Meningitis
TTY Biopharm
 2011-02
NCT01715922 UNKNOWN
Cryptococcal Meningitis; HIV
ANRS, Emerging Infectious Diseases
 2012-05 PHASE2; PHASE3
NCT01172964 COMPLETED
Adult Anaplastic Astrocytoma; Recurrent Grade III Glioma; Recurrent Grade IV Glioma; Adult Anaplastic Oligodendroglioma; Adult Brain Tumor; Adult Giant Cell Glioblastoma; Adult Glioblastoma; Adult Gliosarcoma; Adult Mixed Glioma; Recurrent Adult Brain Tumor; Adult Anaplastic Oligoastrocytoma; Recurrent High Grade Glioma
City of Hope Medical Center
 2010-08 PHASE1
NCT01562132 TERMINATED
Cryptococcal Infection Disseminated
Yale University
 2013-09 PHASE2
NCT00978107 COMPLETED
Hepatocellular Carcinoma
Transgene
 2009-09 PHASE1
NCT00847678 TERMINATED
Cryptococcal Meningitis
Novartis Pharmaceuticals
 2006-08 PHASE2
NCT00000708 COMPLETED
Meningitis, Cryptococcal; HIV Infections
National Institute of Allergy and Infectious Diseases (NIAID)
NCT00002075 COMPLETED
Meningitis, Cryptococcal; HIV Infections
Pfizer
NCT00002305 COMPLETED
Meningitis, Cryptococcal; HIV Infections
Pfizer
NCT00002113 COMPLETED
Meningitis, Cryptococcal; HIV Infections
Pfizer
NCT00000639 COMPLETED
Meningitis, Cryptococcal; HIV Infections
National Institute of Allergy and Infectious Diseases (NIAID)
NCT00012467 COMPLETED
Meningitis, Cryptococcal; HIV Infections
InterMune
 2000-01 PHASE2
NCT00000776 COMPLETED
Meningitis, Cryptococcal; HIV Infections
National Institute of Allergy and Infectious Diseases (NIAID)
 PHASE2

(data from https://clinicaltrials.gov, updated on 2026-05-28)

Check the Flucytosine (5-Fluorocytosine) product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Compliance for Clinical Use

Mechanism and Biochemical Profile

Flucytosine acts as a fluorinated pyrimidine analogue that is intracellularly metabolized into active fluorinated metabolites, disrupting fungal RNA protein synthesis via 5-fluorouridinetriphosphate and inhibiting DNA synthesis through 5-fluorodeoxyuridinemonophosphate formation. This dual blockade of essential nucleic acid processing halts cell proliferation, providing the mechanistic foundation for its investigation in cryptococcal meningitis and advanced brain tumors.

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.