# Galeterone

Source: https://onco.cc/drugs/galeterone/  
OnCo record `galeterone` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

An experimental prostate cancer tablet meant to work in men whose cancer makes a broken form of the androgen receptor. The trial designed to prove it collapsed.

## Summary

Galeterone is a steroidal compound with three claimed activities against the androgen axis at once: inhibition of CYP17 lyase, direct androgen receptor antagonism, and degradation of androgen receptor protein including the constitutively active splice variant AR-V7, which lacks the ligand-binding domain and so cannot be blocked by abiraterone or enzalutamide.

That last property was the whole commercial thesis. AR-V7 detected in circulating tumour cells predicts a poor response to abiraterone and enzalutamide, so a drug that degrades the receptor rather than blocking its ligand pocket should work where they do not. Tokai Pharmaceuticals tested the thesis in ARMOR3-SV, the only phase 3 trial in prostate cancer to select men by AR-V7 status.

The trial prescreened 953 men to find 73 who were AR-V7 positive, a prevalence of 8 percent (95 percent confidence interval 6 to 10). Of those, 38 were randomised before the data monitoring committee recommended early closure: too many men progressed and left the trial before the required radiographs. Tokai stopped developing galeterone. No approval was ever sought.

## Fields

- Kind: Treatment
- Status: withdrawn
- Last checked: 2026-09-25
- Also known as: TOK-001; VN/124-1
- Code: TOK-001
- Modality: small molecule
- Mechanism: CYP17 lyase inhibition, androgen receptor antagonism and androgen receptor protein degradation, including the AR-V7 splice variant.

## Sources

- ARMOR3-SV (European Urology 2019): https://doi.org/10.1016/j.eururo.2019.08.034
- ClinicalTrials.gov NCT02438007: https://clinicaltrials.gov/study/NCT02438007

## Connected records

- cancers: [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- targets: [Androgen receptor](https://onco.cc/targets/androgen-receptor/), [CYP17A1 (17-alpha-hydroxylase/17,20-lyase)](https://onco.cc/targets/cyp17a1/)
- terms: [Androgen receptor pathway inhibitor (ARPI)](https://onco.cc/terms/arpi/), [AR-V7 splice variant](https://onco.cc/terms/ar-v7/), [Castration-resistant prostate cancer (CRPC)](https://onco.cc/terms/castration-resistance/)
- trials: [ARMOR3-SV](https://onco.cc/trials/armor3-sv/)

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JSON: https://onco.cc/api/v1/entities/galeterone.json