Clinical trial · Interventional
First-in-Human Study of ATX-559, an Oral Inhibitor of DHX9, in Patients With Advanced or Metastatic Solid Tumors, and Molecularly Defined Cancers
A Phase 1/2, Open-Label, Dose-Escalation and Expansion First-In-Human Study of ATX-559, an Oral Inhibitor of the Helicase DHX9, in Patients With Locally Advanced or Metastatic Solid Tumors and Molecularly Defined Cancers
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Why stopped (as posted): The study was terminated by sponsor based on the adverse event profile.
Summary
Brief summary (as posted)
The goal of this study is to identify a safe and tolerated dose of the orally administered DHX9 inhibitor ATX-559. In addition, this study will evaluate the pharmacokinetics, pharmacodynamics and preliminary antitumor activity of ATX-559 in patients with advanced solid tumors and molecularly defined cancers.
Conditions
Conditions (6)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Advanced Solid Tumors | Solid Neoplasm | CURATED_BROADER | 0.80 |
| Breast Cancer Recurrent | — | UNRESOLVED | — |
| Colon Cancer | Malignant Colon Neoplasm | CURATED_EXACT | 0.92 |
| Colorectal Cancer Metastatic | — | UNRESOLVED | — |
| Endometrial Cancer | Malignant Endometrial Neoplasm | CURATED_BROADER | 0.80 |
| Rectal Adenocarcinoma | Rectal Adenocarcinoma | ONTOLOGY_EXACT | 0.98 |
Interventions
Interventions (1)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| ATX-559 | Drug | — | UNRESOLVED |
Design
Arms and outcomes
Arms (3)
- type
- EXPERIMENTAL
- label
- Dose escalation
- description
- Subjects will be enrolled at various doses or schedules of ATX-559 to identify the RP2D
- interventionNames
- Drug: ATX-559
- type
- EXPERIMENTAL
- label
- Dose Expansion: MSI-H/dMMR solid tumors
- interventionNames
- Drug: ATX-559
- type
- EXPERIMENTAL
- label
- Dose Expansion: BRCA1- or BRCA2-deficient HER2-negative breast cancer
- interventionNames
- Drug: ATX-559
Primary outcomes (2)
Eligibility
Eligibility (as posted)
- Sex
- All
- Minimum age
- 18 Years
Show eligibility criteria text
Key Inclusion Criteria: * Patients with histologically confirmed solid tumors who have locally recurrent or metastatic disease * Refractory to or relapsed after all standard therapies with proven clinical benefit, unless as deemed by the Investigator, the subject is not a candidate for standard treatment, there is no standard treatment, or the subject refuses standard treatment after expressing an understanding of all available therapies with proven clinical benefit * For the expansion cohorts, participants must have histological confirmation of the specified tumor types: * BRCA1 or BRCA2 deficient, HER2 negative metastatic breast cancer * dMMR or MSI-H with unresectable or metastatic solid tumors * There is no limit to the number of prior treatment regimens * Have measurable or evaluable disease * Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 Key Exclusion Criteria: * Clinically unstable central nervous system (CNS) tumors or brain metastasis * Any other concurrent anti-cancer treatment * Has undergone a major surgery within 3 weeks of starting study treatment * Medical issue that limits oral ingestion or impairment of gastrointestinal function that is expected to significantly reduce the absorption of ATX-559 * Clinically significant (ie, active) or uncontrolled cardiovascular disease * Unable to transition off strong or moderate CYP2C8 inhibitors or inducers * Pregnancy or intent to breastfeed or conceive a child within the projected duration of treatment Other inclusion and exclusion criteria as defined in the study protocol
References
Publications (0)
Data not yet available