Recruiting
Phase 1
Phase 2

ATX-898

Sponsor:

Antares Therapeutics, Inc

Code:

NCT07767474

Conditions

Advanced Solid Tumors

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

ATX-898

ATX-898

ATX-898

ATX-898

ATX-898

Study Details

Brief 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. 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.

Conditions

Advanced Solid Tumors

Study ID

NCT07767474

Start date

Aug 31, 2026

Status verified date

Oct, 2026

Completion date

Jan 31, 2030

Anticipated

Primary completion date

Oct 28, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • 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)

  • 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

Exclusion Criteria:

  • 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

Study Design

Enrollment

343 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Part 1a: Monotherapy Dose Escalation

ATX-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

experimental: Part 1b1: Monotherapy Dose Expansion Cohort Disease Group 1

ATX-898 will be given at the recommended dose for expansion (RDE) for the treatment of participants with selected advanced or metastatic ovarian cancer

experimental: Part 1b2: Monotherapy Dose Expansion Cohort Disease Group 2

ATX-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

experimental: Part 1b2: Monotherapy Dose Expansion Cohort Disease Group 3

ATX-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

experimental: Part 2a 1: Combination Dose Escalation

ATX-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

experimental: Part 2b 1: Combination Dose Expansion

ATX-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

experimental: Part 2b 2: Combination Dose Expansion

ATX-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

experimental: Part 2a 2: Combination Dose Escalation

ATX-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

Interventions

ATX-898

Doses defined per protocol

ATX-898

RDE

ATX-898

RDE

ATX-898

RDE

ATX-898

Doses defined per protocol

ATX-898, fulvestrant, ribociclib

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

ATX-898, fulvestrant, ribociclib

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

ATX-898, fulvestrant, ribociclib

Doses defined per protocol

Primary outcome measure

  • Part 1a monotherapy dose escalation - Occurrence of Dose limiting toxicities (DLTs) [ Time Frame: 12 months ]
  • Part 1a monotherapy dose escalation - Maximally tolerated/tested dose (MTD) [ Time Frame: 12 months ]
  • Part 1a monotherapy dose escalation - Recommended dose for expansion (RDE) [ Time Frame: 12 months ]
  • Part 1a monotherapy dose escalation - Treatment emergent adverse events (TEAEs) [ Time Frame: 12 months ]
  • Part 1b monotherapy dose expansion - Objective Response Rate (ORR) [ Time Frame: 24 months ]
  • Part 2a combination dose escalation - Occurrence of Dose limiting toxicities (DLTs) [ Time Frame: 18 months ]
  • Part 2a combination dose escalation - Maximally tolerated/tested dose (MTD) [ Time Frame: 18 months ]
  • Part 2a combination dose escalation - Recommended dose for expansion (RDE) [ Time Frame: 18 months ]
  • Part 2a combination dose escalation - Treatment emergent adverse events (TEAEs) [ Time Frame: 18 months ]
  • Part 2b combination dose expansion - Objective Response Rate (ORR) [ Time Frame: 36 months ]

Central Contacts and Locations

Central contacts

Antares Medical Monitor

+1 781-288-5760clinicaltrials@antaresrx.com

Locations

START Dallas Fort Worth Cancer Center

Recruiting

Fort Worth, Texas, United States, 76104

Contacts

Antares Medical Monitor

+1 781-288-5760clinicaltrials@antaresrx.com

MD Anderson Cancer Center

Recruiting

Houston, Texas, United States, 77030

Contacts

Antares Medical Monitor

+1 781-288-5760clinicaltrials@antaresrx.com

START San Antonio Cancer Center

Recruiting

San Antonio, Texas, United States, 78229

Contacts

Antares Medical Monitor

+1 781-288-5760clinicaltrials@antaresrx.com

START Mountain Region Cancer Center

Recruiting

West Valley City, Utah, United States, 84119

Contacts

Antares Medical Monitor

+1 781-288-5760clinicaltrials@antaresrx.com

NEXT Virginia Cancer Center- Merrifield Tech Center

Recruiting

Fairfax, Virginia, United States, 22031

Contacts

Antares Medical Monitor

781-288-5760clinicaltrials@antaresrx.com

More Information

Sponsor

Antares Therapeutics, Inc

Last update posted

Oct 16, 2026

Last verified

Oct, 2026

Keywords

  • locally advanced or metastatic solid tumors
  • (HR) positive (HR+) breast cancer
  • HER2 negative (HER2-) breast cancer

Trial information was received from ClinicalTrials.gov and was last updated on 2026-10-17. This information was provided to ClinicalTrials.gov by Antares Therapeutics, Inc on 2026-10-16. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.