TheraRadar
Data updated: May 26, 2026

CYSTAGON (cysteamine bitartrate)

Trial Activity: Declining 1 active trials
Renal Approved 1994-08-15

Cystagon helps children and adults who have nephropathic cystinosis, a metabolic condition where cystine builds up and damages organs like the kidneys. This medication is used to manage the accumulation of these crystals, which otherwise lead to serious issues like renal failure, growth problems, and vision sensitivity. It is a critical therapy for preventing the progressive damage to the muscles, eyes, and central nervous system associated with the disease.

Source: FDA Label • Viatris

How CYSTAGON Works

This drug works by entering the lysosomes within cells to trigger a chemical reaction with stored cystine. It converts the trapped cystine into two different substances—cysteine and a cysteine-cysteamine disulfide—that are able to exit the lysosome. This process prevents the toxic accumulation of cystine crystals that would otherwise damage the kidneys and other vital organs.

Development Insights

Amgen conducting 4 trials (67%)
4 indications explored (Focused)
cystinosis (3 trials)
inherited mitochondrial disease, including leigh syndrome (1 trials)
mitochondrial diseases (1 trials)
1
Indication
--
Phase 3 Trials
1
Priority Reviews
31
Years on Market

Details

Status
Prescription
First Approved
1994-08-15
Routes
ORAL
Dosage Forms
CAPSULE

Companies

Active Ingredient: CYSTEAMINE BITARTRATE

CYSTAGON Approval History

1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
Original
New Indication
New Form
Label Update
20 FDA actions from 1994 to 2016
Jun 2016 SUPPL Priority
Mfg · Manufacturing (CMC)
Jun 2015 SUPPL Priority
Mfg · Manufacturing (CMC)
Jun 2007 SUPPL
Label · Labeling

What CYSTAGON Treats

1 indications

CYSTAGON is approved for 1 conditions since its original approval in 1994. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Nephropathic Cystinosis
Source: FDA Label

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PROCYSBI
CYSTEAMINE BITARTRATE
1 shared
HORIZON
Shared indications:
Nephropathic Cystinosis
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Clinical Trial Registry

4 trials
Trial Sponsor ID Phase Status Title
NCT05994534 INCA C-23-01 Ph 1, Ph 2 recruiting PK and PD Study of NPI-001 and Cysteamine Bitartrate
NCT02023866 MITO-001 results posted RP103-MITO-001 Ph 2 completed Open-Label, Dose-Escalating Study Assessing Safety, Tolerability, Efficacy, of RP103 in Mitochondrial Disease
NCT02473445 results posted RP103-MITO-002 Ph 2 terminated A Long-term Extension of Study RP103-MITO-001 (NCT02023866) to Assess Cysteamine Bitartrate Delayed-release Capsules (RP103) in Children With Inherited Mitochondrial Disease
NCT03883984 Hershey-101 Ph 1 completed Cysteamine for Asthma
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Active Pipeline

Pro

Ongoing clinical trials by development phase

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Key Completed Trials

Pro

Completed studies with published results, ranked by significance

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Trial Timeline

Full development history with FDA approval milestones

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Understanding FDA Approval Types
Count Type What it means
- ORIG Original approval - drug first enters market
- SUPPL - Efficacy New indication (new disease/condition approved)
- SUPPL - Labeling Label text changes (warnings, dosing updates)
- SUPPL - Manufacturing Production changes (new facility)
- SUPPL - Chemistry Formulation changes (new dosage strength)

Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.

CYSTAGON FDA Label Details

Indications & Usage

FDA Label (PDF)

CYSTAGON is indicated for the treatment of Nephropathic Cystinosis.

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Data Sources

Data sourced from official FDA and NIH databases. Click links to verify on original sources.

How We Calculate These Metrics

Trial Activity Stage

Measures the current development activity pattern based on trial phases, status, and trends. Important: This measures R&D activity, not commercial lifecycle.

Trial statuses: "Active" means recruiting or ongoing. "Completed" means reached planned endpoint. "Terminated" means stopped early—often due to safety, efficacy, or business reasons.

  • Growth: High proportion of early-phase trials (Phase 1/2), active development
  • Expansion: Significant Phase 3 activity, approaching or pursuing approvals
  • Mature: Substantial Phase 4 post-marketing studies
  • Stable: Mixed phase distribution, steady development
  • Declining: Low active trial ratio, reduced R&D investment