Study of GS-2426 in Participants With Advanced Solid Tumors

A Phase 1, Multicenter, Open-Label Clinical Study to Evaluate the Safety and Tolerability of GS-2426 in Participants With Advanced MTAP-Deleted Solid Tumors

The goal of this clinical study is to learn more about the study drug GS-2426, and how safe and tolerable it is in participants with advanced methylthioadenosine phosphorylase (MTAP)-deleted solid tumors.

The primary objective of this study is to evaluate the safety and tolerability of GS-2426 in participants with MTAP-deleted advanced solid tumors and to determine the maximum tolerated dose (MTD)/maximum administered dose (MAD) and the recommended phase II dose (RP2D).

Study Overview

• Status: Not yet recruiting
• Conditions: Advanced Solid Tumors
• Intervention / Treatment: Drug: GS-2426

• Study Type: Interventional
• Enrollment (Estimated): 174
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Gilead Clinical Study Information Center; Phone Number: 1-833-445-3230 (GILEAD-0); Email: GileadClinicalTrials@gilead.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

• Participants 18 years of age or older (≥ 19 years old for participants in South Korea).
• Histologically or cytologically confirmed advanced malignant solid tumors, who have progressed on, are intolerant to or are ineligible for standard therapy, or have no standard treatment options.
• Participant tumors are MTAP-deficient.
• Adequate organ function
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• All participants must provide a pretreatment tumor tissue sample.

Key Exclusion Criteria:

• Participants with plans to breastfeed during the study period or within 7 days following the last dose of study intervention.
• Have not recovered (ie, returned to Grade 1 or baseline) from clinically significant AEs due to a previously administered agent or a previous intervention as assessed by the investigator.
• Active second malignancy. Individuals with a history of malignancy who have been completely treated with no evidence of active cancer for 5 years prior to enrollment, or individuals with surgically cured tumors with low risk of recurrence may be enrolled.
• Requirement for ongoing therapy with any prohibited medications .
• Prior therapy with a PRMT5 inhibitor or methionine adenosine transferase 2a (MAT2A ) inhibitor.
• Have serious infection requiring antibiotics within 14 days prior to the first dose.
• Uncontrolled concurrent diseases

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Phase 1a: Monotherapy Dose Escalation; Participants will receive escalating doses of GS-2426 monotherapy, until disease progression, or until the participant meets other study drug discontinuation criteria as specified in protocol, or up to a maximum of 105 week, whichever occurs first.	Drug: GS-2426; Administered Orally
Experimental: Phase 1b: Monotherapy Dose Expansion; Participants will be enrolled in different indication-specific cohorts. Participants will receive GS-2426 monotherapy at the recommended dose until disease progression, or until the participant meets other study drug discontinuation criteria as specified in protocol, or up to a maximum of 105 weeks, whichever occurs first.	Drug: GS-2426; Administered Orally

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Percentage of Participants Experiencing Treatment-Emergent Adverse Events (AEs) and Serious Adverse Events (SAE)	First dose up to 30 days post last dose (up to 105 weeks)
Percentage of Participants Experiencing Clinical Laboratory Abnormalities	First dose up to 30 days post last dose (up to 105 weeks)
Percentage of Participants Experiencing any Dose-limiting Toxicities (DLTs)	First dose up to 21 days post first dose
Maximum Tolerated Dose (MTD)/Maximum Administered Dose (MAD)	First dose up to 21 days post first dose
Recommended Phase 2 Dose (RP2D)	Predose to end of study (up to 105 weeks)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma Concentration of GS-2426		Predose and postdose up to end of treatment (up to 105 weeks)
Pharmacokinetic (PK) Parameter: AUC0-24h of GS-2426	AUC0-24h is defined as the area under concentration versus time from 0 to 24 hours.	Predose and postdose up to end of treatment (up to 105 weeks)
PK Parameters: Cmax of GS-2426	Cmax is defined as the maximum observed plasma drug concentration.	Predose and postdose up to end of treatment (up to 105 weeks)
PK Parameters: Tmax of GS-2426	Tmax is defined as the time to peak plasma drug concentration of GS-2426.	Predose and postdose up to end of treatment (up to 105 weeks)

Collaborators and Investigators

• Sponsor: Gilead Sciences
• Investigators: Study Director: Gilead Study Director, Gilead Sciences

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2029

Study Registration Dates

• First Submitted: May 15, 2026
• First Submitted That Met QC Criteria: May 15, 2026
• First Posted (Actual): May 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 15, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: GH31C101A

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No