A Study of PARG Inhibitor ETX-19477 in Patients With Advanced Solid Malignancies

NCT ID: NCT06395519

Last Updated: 2025-08-05

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

PHASE1/PHASE2

Total Enrollment

120 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-05-13

Study Completion Date

2026-12-31

Brief Summary

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This is a two-part, open-label, multicenter, dose escalation and dose expansion study designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PDx), and anti- tumor activity of ETX-19477, a novel reversible small molecule inhibitor of PARG.

Detailed Description

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A hallmark of many cancer cells is replication stress, which is characterized by the slowing or stalling of replication forks during the DNA replication process, leading to the accumulation of damaged DNA. The cellular response to replication stress is the activation of cell-cycle checkpoints and the DNA damage response (DDR) pathway to arrest the cell cycle and promote repair of the damaged DNA.

Poly (ADP) ribose glycohydrolase (PARG) plays a critical role in DDR with genetic depletion or inhibition by reference compounds resulting in increased numbers of single-strand breaks (SSBs) and double-strand breaks (DSBs) and reduced kinetics of break repair. In addition, under conditions of replication stress in cancer cells, PARG depletion or inhibition has been shown to inhibit proliferation and arrest cells in the S or G2 phase of the cell cycle and/or induce apoptosis alone or in combination with DNA damaging agents or replication stress inducers. The replication stress response represents a cancer-specific vulnerability, which can be targeted by PARG small molecule inhibition.

Conditions

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Advanced or Metastatic Solid Tumors Breast Cancer Ovarian Cancer Prostate Cancer Epithelial Ovarian Cancer BRCA2 Mutation ER+ Breast Cancer Castrate Resistant Prostate Cancer BRCA1 Mutation BRCA Mutation Endometrial Cancer Colorectal Cancer Gastric Cancer

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

SEQUENTIAL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Phase 1 Part 1: Monotherapy Dose Escalation

Participants will be assigned to a dose level.

Group Type EXPERIMENTAL

ETX-19477

Intervention Type DRUG

Oral medication taken daily

Phase 1 Part 2: Monotherapy Dose Expansion

After a dose is decided in Part 1, participants entering part 2 will be assigned to a dose level.

Group Type EXPERIMENTAL

ETX-19477

Intervention Type DRUG

Oral medication taken daily

Interventions

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ETX-19477

Oral medication taken daily

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Males and females of age ≥ 18 years at the time of signing the informed consent document.
* Histologically or cytologically confirmed advanced (incurable recurrent, unresectable, or metastatic) solid cancer, excluding primary central nervous system (CNS) tumors.
* Any solid tumor malignancy, excluding primary CNS tumors, with progression on or after or intolerance to most recent systemic therapy. Preferential enrollment consideration will be made for patients with known BRCA2 mutations resulting in loss of function.
* Progression on or after or intolerance to most recent systemic therapy. Prior treatment in the recurrent/metastatic setting; patients must have received approved standard therapy that is available to the patient that is known to confer clinical benefit, unless this therapy is contraindicated, intolerable to the patient, or is declined by the patient.
* No investigational agent within 3 weeks or 5 half-lives (whichever is shorter; minimum of 2 weeks) prior to first dose of study drug.
* Life expectancy of at least 3 months.

Exclusion Criteria

* Receiving continuous corticosteroids at prednisone-equivalent dose of \>10 mg/day. Chronic systemic corticosteroid therapy for physiologic replacement (≤10 mg/day of prednisone equivalents) and the use of non-systemic corticosteroids (e.g., inhaled, topical, intra-nasal, intra-articular, or ophthalmic) are permitted.
* Definitive radiotherapy within 6 weeks and palliative radiation within 2 weeks prior to the first dose of study drug.
* Symptomatic untreated or progressing brain metastases. Stable, treated brain metastases are allowed if no evidence of radiologic or clinical progression or increasing corticosteroid use for at least 4 weeks.
* Impairment of gastrointestinal (GI) function or GI disease that may significantly alter the absorption of ETX-19477 and no history of bowel obstruction within 6 months prior to enrollment.
* Known symptomatic and radiologically progressing or leptomeningeal disease (LMD). If LMD has been reported radiographically on baseline magnetic resonance imaging (MRI), but is not suspected clinically by the Investigator, the patient must be free of neurological symptoms of LMD.
* Resting ECG with QT interval calculated using the Fridericia's formula (QTcF) \>470 msec on 2 or more timepoints within a 24-hour period, or history or family history of congenital long QT syndrome.
* History of myocardial infarction or unstable angina within 6 months prior to enrollment, or clinically significant cardiac disease, such as ventricular arrhythmia requiring therapy, uncontrolled hypertension, clinically significant uncontrolled arrhythmias, or any history of symptomatic congestive heart failure.
* Known active or chronic infection (viral, bacterial, or fungal), including tuberculosis, hepatitis B, hepatitis C, or AIDS-related illness. Controlled infections, including HIV and "cured" hepatitis C (no active fever, no evidence of systemic inflammatory response syndrome) that are stable with undetectable viral load on antiviral treatment are not exclusionary.
* Acute or chronic uncontrolled renal disease, pancreatitis, or liver disease (with exception of patients with Gilbert's Syndrome, asymptomatic gallstones, liver metastases, or stable chronic liver disease per Investigator assessment).
* Known other previous/current malignancy requiring treatment within ≤2 years except for limited disease treated with curative intent, such as carcinoma in situ, squamous or basal cell skin carcinoma, or superficial bladder carcinoma.
* Patients receiving proton pump inhibitors (PPIs), strong cytochrome P450 (CYP)3A inhibitors and inducers, or P-glycoprotein (P-gp) inhibitors. Patients should not receive PPIs within 7 days prior to first dose of study drug. Strong CYP3A inducers or inhibitors or strong P-gp inhibitors should not be given within 6 half-lives prior to first dose of study drug.
* Patients currently treated with therapeutic doses of warfarin sodium (Coumadin®) or any other coumarin-derivative anticoagulants
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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858 Therapeutics, Inc.

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Daniel McCormick

Role: STUDY_DIRECTOR

858 Therapeutics, Inc.

Locations

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Mayo Clinic

Phoenix, Arizona, United States

Site Status RECRUITING

Yale University, Yale Cancer Center

New Haven, Connecticut, United States

Site Status RECRUITING

Mayo Clinic

Jacksonville, Florida, United States

Site Status RECRUITING

Massachusetts General Hospital

Boston, Massachusetts, United States

Site Status RECRUITING

Mayo Clinic

Rochester, Minnesota, United States

Site Status RECRUITING

Laura & Isaac Perlmutter Cancer Center at NYU Langone Health

New York, New York, United States

Site Status RECRUITING

Memorial Sloan Kettering Cancer Center

New York, New York, United States

Site Status RECRUITING

Thomas Jefferson University, Sidney Kimmel Comprehensive Cancer Center

Philadelphia, Pennsylvania, United States

Site Status RECRUITING

MD Anderson Cancer Center

Houston, Texas, United States

Site Status RECRUITING

START Center for Cancer Care - Mountain Region

Salt Lake City, Utah, United States

Site Status RECRUITING

Virginia Cancer Specialists

Fairfax, Virginia, United States

Site Status RECRUITING

Fred Hutchinson Cancer Center

Seattle, Washington, United States

Site Status RECRUITING

Countries

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United States

Central Contacts

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858 Therapeutics, Inc.

Role: CONTACT

(858) 987-8380

Other Identifiers

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ETX-19477-101

Identifier Type: -

Identifier Source: org_study_id

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