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NCT Number: NCT07767474

A Study to Evaluate ATX-898 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.

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Key information

Conditions

Advanced Solid Tumors Breast Diseases Breast Neoplasms Neoplasms Neoplasms by Site Skin Diseases Skin and Connective Tissue Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1 / Phase 2

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

ATX-898

Drug

Doses defined per protocol

ATX-898, fulvestrant, ribociclib

Drug

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

Primary outcomes

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

    Time frame: 12 months

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

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

    Time frame: 12 months

    Maximum dose deemed safe and well tolerated during dose escalation

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

    Time frame: 12 months

    Monotherapy dose recommended to test during dose expansion

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

    Time frame: 12 months

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

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

    Time frame: 24 months

    Percentage of participants with confirmed CR or PR per RECIST 1.1

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

    Time frame: 18 months

    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

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

    Time frame: 18 months

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

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

    Time frame: 18 months

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

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

    Time frame: 18 months

    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

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

    Time frame: 36 months

    Percentage of participants with confirmed CR or PR per RECIST 1.1

Secondary outcomes

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

    Time frame: 12 months

    Cmax of ATX-898 following treatment

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 months

    Percentage of participants with confirmed CR or PR per RECIST 1.1

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

    Time frame: 24 Months

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

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

    Time frame: 12 months

    Cmax of ATX-898 following treatment at RDE

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 18 months

    Percentage of participants with confirmed CR or PR per RECIST 1.1

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

    Time frame: 12 months

    Cmax of ATX-898 following treatment

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 36 months

    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

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

    Time frame: 12 months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

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

    Time frame: 12 Months

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

Study contacts

Contact information is provided by the study sponsor or research team.

For questions concerning enrollment

CONTACT

[email protected]

000-000-0000

Sponsors and collaborators

Lead sponsor

Antares Therapeutics, Inc

Industry

Registry information

Official study title

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

Important dates

Study start
2026
Primary completion
2028
Study completion
2030
First posted
Aug 17, 2026
Registry last updated
Aug 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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