# ATX-559

Source: https://onco.cc/drugs/atx-559/  
OnCo record `atx-559` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

ATX-559 is an experimental oral small molecule from Accent Therapeutics, in phase 1 trials for advanced solid tumours and molecularly defined cancers; its current status is not stated.

## Summary

ATX-559 is an oral small molecule from Accent Therapeutics. An oral inhibitor of the RNA helicase DHX9, aimed at molecularly defined tumours with genomic instability and replication stress. Its furthest stage is phase 1, for advanced solid tumours and molecularly defined cancers (registry lists breast, colorectal, rectal and endometrial cancer). ClinicalTrials.gov registers it in one study linked below. First-in-human NCT06625515 TERMINATED: registry reason 'The study was terminated by sponsor based on the adverse event profile.' ATX-559 no longer appears in the pipeline table on the company site (only in its past presentations list). Whether it works in people has not been established unless a trial below reports it.

## Fields

- Kind: Treatment
- Status: phase-1
- Last checked: 2026-11-03
- Tags: pipeline; ctgov-ingest
- Code: ATX-559
- Modality: Oral small molecule
- Mechanism: An oral inhibitor of the RNA helicase DHX9, aimed at molecularly defined tumours with genomic instability and replication stress.

## Sources

- Accent Therapeutics: clinicaltrials.gov: https://clinicaltrials.gov/api/v2/studies/NCT06625515
- Accent Therapeutics: accenttx.com: https://accenttx.com/approach-pipeline/
- ClinicalTrials.gov: trials of ATX-559: https://clinicaltrials.gov/search?intr=ATX-559

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Metastatic cancer (cancer that has spread)](https://onco.cc/cancers/metastatic-cancer/)
- targets: [DHX9](https://onco.cc/targets/dhx9/)
- companies: [Accent Therapeutics](https://onco.cc/companies/accent-therapeutics/)
- trials: [First-in-Human Study of ATX-559, an Oral Inhibitor of DHX9, in Patients With Advanced or Metastatic Solid Tumors, and Molecularly Defined Cancers](https://onco.cc/trials/nct06625515/)

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JSON: https://onco.cc/api/v1/entities/atx-559.json