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Advanced Solid TumorsPhase 1/2NCT07767474

A Study to Evaluate ATX-898 in Participants With Advanced Solid Tumors

A Phase 1/2 study testing ATX-898 and ATX-898, fulvestrant, ribociclib in people with Advanced Solid Tumors, run by Antares Therapeutics, Inc at 6 sites in 2 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

Study ATX-898-101 is a phase 1/2 open-label study evaluating the safety, tolerability, pharmacokinetic, and preliminary efficacy of ATX-898 as monotherapy and in combination with anti-neoplastic agents in selected solid tumors. This study consists of 2 parts. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Advanced Solid Tumors
What is being tested?
ATX-898 and ATX-898, fulvestrant, ribociclib
Could I receive a placebo?
No, everyone receives an active treatment
How many people
343 participants
Where
6 sitesin 2 countries
Study dates
31 Aug 2026to 31 Jan 2030
Phase
Phase 1/2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Has histologically or cytologically confirmed advanced solid tumor malignancy that is metastatic or locally advanced and unresectable
  • Is ≥18 years of age at the time of signing the informed consent form
  • ECOG performance status score of 0 or 1
  • Adequate organ function
  • Must consent to a pre-treatment tumor biopsy (collected during screening or have available archival tumor tissue in the past 5 years.
  • For Part 1a (monotherapy dose escalation)
Show all 16Show fewer
  • Has received one or more standard systemic therapies and additional standard therapies are either not available, or participant ineligible for available standard therapies For Part 1b (monotherapy dose expansion)
  • b1: Has platinum-resistant or refractory metastatic ovarian cancer
  • b2: Has recurrent or metastatic gynecologic cancer excluding the cancers eligible for b1
  • b3: Has recurrent advanced or metastatic solid tumor excluding the cancers eligible for b1 or b2
  • Has at least 1 measurable lesion per RECIST 1.1
  • For Part 2a (combination dose escalation)
  • Has confirmed HR+ HER2 - (including HER2 low and ultra low) status
  • Has received prior therapy in the metastatic For Part 2b (combination dose expansion)
  • Has confirmed HR+ HER2 - (including HER2 low and ultra low) status
  • Treatment-naïve or has received prior therapy in the metastatic setting

Who cannot join

  • Has history (within ≤2 years before screening) of a solid tumor or hematological malignancy that is histologically distinct from the cancer being studied
  • Has symptomatic CNS metastases at screening or asymptomatic CNS metastases requiring corticosteroids to control symptoms within 28 days prior to the first dose of ATX-898.
  • Has toxicities from previous anticancer therapies that have not resolved to baseline levels or to CTCAE Grade ≤1, with the exception of alopecia any grade and Grade ≤2 peripheral neuropathy
  • Has any condition for which, in the opinion of the Investigator, participation would not be in the best interest of the participant or would prevent, limit, or confound the protocol-specified assessments
  • Cohort Specific:
  • For abemaciclib cohorts only: has a history of any events of cardiac etiology that would contraindicate dosing with abemaciclib
  • For ribocicilib only: has history of pneumonitis or interstitial lung disease

Trial locations and contacts

6 sites in 2 countries. Contact the study team or a site near you to ask about taking part.

Antares Medical Monitor contact

+1 781-288-5760

clinicaltrials@antaresrx.com

6 sites in 2 countries

United States5 sites, 5 recruiting

  • NEXT Virginia Cancer Center- Merrifield Tech Center

    Fairfax, Virginia, 22031

    Antares Medical Monitor, 781-288-5760, clinicaltrials@antaresrx.com

    Recruiting

  • START Dallas Fort Worth Cancer Center

    Fort Worth, Texas, 76104

    Antares Medical Monitor, +1 781-288-5760, clinicaltrials@antaresrx.com

    Recruiting

  • MD Anderson Cancer Center

    Houston, Texas, 77030

    Antares Medical Monitor, +1 781-288-5760, clinicaltrials@antaresrx.com

    Recruiting

  • START San Antonio Cancer Center

    San Antonio, Texas, 78229

    Antares Medical Monitor, +1 781-288-5760, clinicaltrials@antaresrx.com

    Recruiting

  • START Mountain Region Cancer Center

    West Valley City, Utah, 84119

    Antares Medical Monitor, +1 781-288-5760, clinicaltrials@antaresrx.com

    Recruiting

Other trials in United States

Australia1 site, 1 recruiting

  • Linear Clinical Research

    Perth, Western Australia, 6009

    Antares Medical Monitor, +1 781-288-5760, clinicaltrials@antaresrx.com

    Recruiting

Other trials in Australia

About this study

Official title: First-in-human Study of ATX-898, as Monotherapy and in Combination With Other Anti-neoplastic Agents, in Participants With Advanced Solid Tumors

Study ATX-898-101 is a phase 1/2 open-label study evaluating the safety, tolerability, pharmacokinetic, and preliminary efficacy of ATX-898 as monotherapy and in combination with anti-neoplastic agents in selected solid tumors. This study consists of 2 parts. Part 1 evaluates ATX-898 as monotherapy and Part 2 evaluates ATX-898 in combination with anti-neoplastic agents of interest. Both parts will consists of a dose escalation portion and a dose expansion portion.

Being tested
ATX-898, ATX-898, fulvestrant, ribociclib
Keywords
locally advanced or metastatic solid tumors, (HR) positive (HR+) breast cancer, HER2 negative (HER2-) breast cancer
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • ATX-898Drug

    Doses defined per protocol

  • ATX-898Drug

    RDE

  • ATX-898Drug

    RDE

  • ATX-898Drug

    RDE

  • ATX-898Drug

    Doses defined per protocol

  • ATX-898, fulvestrant, ribociclibDrug

    ATX-898 at RDE, Fulvestrant and abemaciclib: doses defined per protocol

  • ATX-898, fulvestrant, ribociclibDrug

    ATX-898 at RDE, Fulvestrant and abemaciclib: doses defined per protocol

  • ATX-898, fulvestrant, ribociclibDrug

    Doses defined per protocol

Study groups in NCT07767474
Study groupRoleWhat they receive
Part 1a: Monotherapy Dose EscalationExperimentalATX-898 will be given at a protocol defined starting dose for the treatment of participants with selected advanced or metastatic solid tumors. Subsequent dose regimen will be determined during study execution
Receives: Drug: ATX-898
Part 1b1: Monotherapy Dose Expansion Cohort Disease Group 1ExperimentalATX-898 will be given at the recommended dose for expansion (RDE) for the treatment of participants with selected advanced or metastatic ovarian cancer
Receives: Drug: ATX-898
Part 1b2: Monotherapy Dose Expansion Cohort Disease Group 2ExperimentalATX-898 will be given at the recommended dose for expansion (RDE) for the treatment of participants with selected advanced or metastatic gynecologic cancers other than ovarian cancers
Receives: Drug: ATX-898
Part 1b2: Monotherapy Dose Expansion Cohort Disease Group 3ExperimentalATX-898 will be given at the recommended dose for expansion (RDE) for the treatment of participants with selected advanced or metastatic solid tumors other than gynecologic cancers
Receives: Drug: ATX-898
Part 2a 1: Combination Dose EscalationExperimentalATX-898 will be given at a recommended starting dose in combination with fulvestrant and abemaciclib both at the protocol defined doses for the treatment of participants with advanced or metastatic HR+HER2- breast cancer. Subsequent dose regimen of ATX-898 will be determined during study execution
Receives: Drug: ATX-898
Part 2b 1: Combination Dose ExpansionExperimentalATX-898 will be given at a recommended dose for expansion (RDE) in combination with fulvestrant and abemaciclib both at the protocol defined doses for the treatment of participants with advanced or metastatic HR+HER2- breast cancer
Receives: Drug: ATX-898, fulvestrant, ribociclib
Part 2b 2: Combination Dose ExpansionExperimentalATX-898 will be given at a recommended dose for expansion (RDE) in combination with fulvestrant and ribociclib both at the protocol defined doses for the treatment of participants with advanced or metastatic HR+HER2- breast cancer
Receives: Drug: ATX-898, fulvestrant, ribociclib
Part 2a 2: Combination Dose EscalationExperimentalATX-898 will be given at a recommended starting dose in combination with fulvestrant and ribociclib both at the protocol defined doses for the treatment of participants with advanced or metastatic HR+HER2- breast cancer Subsequent dose regimen of ATX-898 will be determined during study execution
Receives: Drug: ATX-898, fulvestrant, ribociclib

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Part 1a monotherapy dose escalation - Occurrence of Dose limiting toxicities (DLTs)

    Toxicities occurring within the first treatment cycle (28 days). DLTs will be assessed in severity by the investigators per CTCAE v 6.0

    Measured: 12 months

  2. Part 1a monotherapy dose escalation - Maximally tolerated/tested dose (MTD)

    Maximum dose deemed safe and well tolerated during dose escalation

    Measured: 12 months

  3. Part 1a monotherapy dose escalation - Recommended dose for expansion (RDE)

    Monotherapy dose recommended to test during dose expansion

    Measured: 12 months

  4. Part 1a monotherapy dose escalation - Treatment emergent adverse events (TEAEs)

    Any adverse event (AE) either reported for the first time or worsening of a pre-existing event after first dose of study drug.

    Measured: 12 months

  5. Part 1b monotherapy dose expansion - Objective Response Rate (ORR)

    Percentage of participants with confirmed CR or PR per RECIST 1.1

    Measured: 24 months

  6. Part 2a combination dose escalation - Occurrence of Dose limiting toxicities (DLTs)

    Toxicities occurring within the first treatment cycle of combination therapy (28 days). DLTs will be assessed in severity by the investigators per CTCAE v 6.0

    Measured: 18 months

  7. Part 2a combination dose escalation - Maximally tolerated/tested dose (MTD)

    Maximum dose deemed safe and well tolerated during dose escalation of with combination treatment

    Measured: 18 months

  8. Part 2a combination dose escalation - Recommended dose for expansion (RDE)

    Recommended dose for expansion (RDE) Monotherapy dose recommended to test during dose expansion of combination treatment 18 months

    Measured: 18 months

  9. Part 2a combination dose escalation - Treatment emergent adverse events (TEAEs)

    Any adverse event (AE) either reported for the first time or worsening of a pre-existing event after first dose of study drug. 18 months

    Measured: 18 months

  10. Part 2b combination dose expansion - Objective Response Rate (ORR)

    Percentage of participants with confirmed CR or PR per RECIST 1.1

    Measured: 36 months

Secondary outcomes (24)

  1. Part 1a monotherapy dose escalation - Pharmacokinetic assessment Cmax

    Cmax of ATX-898 following treatment

    Measured: 12 months

  2. Part 1a monotherapy dose escalation - Pharmacokinetic assessment Tmax

    Time it takes for the study drug to reach peak concentration (Cmax) in the blood following treatment

    Measured: 12 Months

  3. Part 1a monotherapy dose escalation - Pharmacokinetic assessment AUC

    Area under the conc-time curve exposure of the study drug following treatment

    Measured: 12 Months

  4. Part 1a monotherapy dose escalation - Pharmacokinetic assessment T 1/2

    Time required for the concentration of study drug in the body to reduce by half following treatment

    Measured: 12 Months

  5. Part 1a monotherapy dose escalation - Pharmacokinetic assessment Ctrough

    Lowest measured concentration of study drug in the blood right before the next scheduled dose

    Measured: 12 Months

  6. Part 1a monotherapy dose escalation - Objective Response Rate (ORR)

    Percentage of participants with confirmed CR or PR per RECIST 1.1

    Measured: 12 months

  7. Part 1b monotherapy dose expansion - Treatment emergent adverse events (TEAEs)

    Any adverse event (AE) either reported for the first time or worsening of a pre-existing event after first dose of study drug

    Measured: 24 Months

  8. Part 1b monotherapy dose expansion - Pharmacokinetic assessment Cmax

    Cmax of ATX-898 following treatment at RDE

    Measured: 12 months

  9. Part 1b monotherapy dose escalation - Pharmacokinetic assessment Tmax

    Time it takes for the study drug to reach peak concentration (Cmax) in the blood following treatment at RDE

    Measured: 12 Months

  10. Part 1b monotherapy dose escalation - Pharmacokinetic assessment AUC

    Area under the conc-time curve exposure of the study drug following treatment at RDE

    Measured: 12 Months

  11. Part 1b monotherapy dose escalation - Pharmacokinetic assessment T 1/2

    Time required for the concentration of study drug in the body to reduce by half following treatment at RDE

    Measured: 12 Months

  12. Part 1b monotherapy dose escalation - Pharmacokinetic assessment Ctrough

    Lowest measured concentration of study drug in the blood right before the next scheduled dose at RDE

    Measured: 12 Months

  13. Part 2a combination dose escalation - Objective Response Rate (ORR)

    Percentage of participants with confirmed CR or PR per RECIST 1.1

    Measured: 18 months

  14. Part 2a monotherapy dose expansion - Pharmacokinetic assessment Cmax

    Cmax of ATX-898 following treatment

    Measured: 12 months

  15. Part 2a monotherapy dose escalation - Pharmacokinetic assessment Tmax

    Time it takes for the study drug to reach peak concentration (Cmax) in the blood following treatment

    Measured: 12 Months

  16. Part 2a monotherapy dose escalation - Pharmacokinetic assessment AUC

    Area under the conc-time curve exposure of the study drug following treatment

    Measured: 12 Months

  17. Part 2a monotherapy dose escalation - Pharmacokinetic assessment T 1/2

    Time required for the concentration of study drug in the body to reduce by half following treatment

    Measured: 12 Months

  18. Part 2a monotherapy dose escalation - Pharmacokinetic assessment Ctrough

    Lowest measured concentration of study drug in the blood right before the next scheduled dose

    Measured: 12 Months

  19. Part 2b combination dose expansion - Treatment emergent adverse events (TEAEs)

    Any adverse event (AE) either reported for the first time or worsening of a pre-existing event after first dose of study drug when given in combination

    Measured: 36 months

  20. Part 2b monotherapy dose expansion - Pharmacokinetic assessment Cmax

    Cmax of ATX-898 following treatment at RDE when given in combination

    Measured: 12 months

  21. Part 2b monotherapy dose escalation - Pharmacokinetic assessment Tmax

    Time it takes for the study drug to reach peak concentration (Cmax) in the blood following treatment at RDE when given in combination

    Measured: 12 Months

  22. Part 2b monotherapy dose escalation - Pharmacokinetic assessment AUC

    Area under the conc-time curve exposure of the study drug following treatment at RDE when given in combination

    Measured: 12 Months

  23. Part 2b monotherapy dose escalation - Pharmacokinetic assessment T 1/2

    Time required for the concentration of study drug in the body to reduce by half following treatment at RDE when given in combination

    Measured: 12 Months

  24. Part 2b monotherapy dose escalation - Pharmacokinetic assessment Ctrough

    Lowest measured concentration of study drug in the blood right before the next scheduled dose at RDE when given in combination

    Measured: 12 Months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted17 Aug 2026
  2. Study start31 Aug 2026
  3. Primary completion28 Oct 2029 (estimated)
  4. Study completion31 Jan 2030 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1/2
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
343 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07767474
Sponsor's protocol ID
ATX-898-101
Status last verified
Oct 2026
First submitted
3 Aug 2026
Last updated
16 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: No individual participant data will be shared due to privacy and confidentiality requirements.

Questions about this trial

What is this clinical trial studying?

A Phase 1/2 study testing ATX-898 and ATX-898, fulvestrant, ribociclib in people with Advanced Solid Tumors, run by Antares Therapeutics, Inc at 6 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 16 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 16 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 6 sites in United States, Australia. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Antares Medical Monitor (+1 781-288-5760, clinicaltrials@antaresrx.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Part 1a monotherapy dose escalation - Occurrence of Dose limiting toxicities (DLTs) (time frame: 12 months). The study lists 10 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07767474.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Oct 2026.

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