Study of RGT-490 in Patients With PIK3CA-Mutated Advanced Solid Tumors

April 16, 2026 updated by: Regor Pharmaceuticals Inc.

A Phase 1/1b Open-Label, Multicenter, First-in-Human Study Evaluating Safety, Tolerability, Pharmacokinetics, and Antitumor Activity of RGT-490 as a Single Agent in Adult Subjects With Locally Advanced or Metastatic PIK3CA-Mutated Solid Tumors Including HR+/HER2- Breast Cancers

This is a phase 1/1b, open-label, multicenter study consisting of sequential parts designed to evaluate the safety, tolerability, and effects pharmacokinetic (PK) profile, and antitumor activity of RGT-490, an investigational oral therapy, in adults with locally advanced or metastatic solid tumors including breast cancer.

Participants enrolled in the study have advanced disease that is not amendable to curative treatment and whose tumors harbor alterations in the PI3KCA gene.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

63

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Texas
      • Houston, Texas, United States, 77054
        • Recruiting
        • Next Houston
      • San Antonio, Texas, United States, 78229
        • Recruiting
        • NEXT San Antonio
    • Virginia
      • Fairfax, Virginia, United States, 22031
        • Recruiting
        • Next Virginia

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults with metastatic or locally advanced, unresectable solid tumors that have progressed on or after at least one available therapy.
  • Presence of one or more documented activating PIK3CA mutation in tumor tissue and/or blood.
  • At least 1 measurable lesion or evaluable disease per RECIST v1.1.
  • An ECOG performance status of 0 or 1.
  • Adequate organ function

Exclusion Criteria:

  • Diabetes mellitus requiring anti-hyperglycemic medication.
  • Prior treatment with PI3Kα inhibitors
  • Symptomatic, untreated, or uncontrolled central nervous system metastases.
  • Receipt of any local or systemic anticancer therapy or investigational anticancer agent within a protocol-defined washout period prior to study treatment.
  • Unresolved clinically significant toxicities from prior anticancer therapy
  • History of a another malignancy within 2 years prior to screening (exception adequately treated cancers).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Phase 1 Dose Escalation (Advanced Solid Tumors with PIK3CA mutation)
RGT-490 given alone as monotherapy
Drug: RGT-490
Oral tablets
Experimental: Phase 1b Dose Expansion (HR+/HER2- locally advanced or metastatic breast cancer)
RGT-490 given alone as monotherapy
Drug: RGT-490
Oral tablets

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of dose limiting toxicities (DLTs)
Time Frame: 4 weeks (1 cycle)
Number of subjects who experience at least 1 Dose Limiting Toxicity (DLT)
4 weeks (1 cycle)
Incidence and grade of Adverse Events (AEs) and Serious Adverse Events (SAEs)
Time Frame: Every cycle (4-week cycles) until study discontinuation, approximately 12 months
Incidence and grade of Adverse Events (AEs) and Serious Adverse Events (SAEs) and AEs leading to dose modifications and dose limiting toxicities (DLTs) to determine the maximum tolerated dose (MTD)
Every cycle (4-week cycles) until study discontinuation, approximately 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Characterize the Cmax (PK) of RGT-490 monotherapy in Dose Escalation
Time Frame: First 3 treatment cycles (each cycle is 28 days)
Maximum observed plasma concentration (Cmax) of RGT-490
First 3 treatment cycles (each cycle is 28 days)
Characterize the Tmax (PK) of RGT-490 monotherapy in Dose Escalation
Time Frame: First 3 treatment cycles (each cycle is 28 days)
Maximum observed plasma concentration (Tmax) of RGT-490
First 3 treatment cycles (each cycle is 28 days)
Characterize the AUC (PK) of RGT-490 monotherapy in Dose Escalation
Time Frame: First 3 treatment cycles (each cycle is 28 days)
Calculated area under the plasma concentration curve (AUC) of RGT-490
First 3 treatment cycles (each cycle is 28 days)
Measure PD effects of RGT-490 monotherapy in Dose Escalation and Phase 1b
Time Frame: First 7 cycles (each cycle is 28 days) and at study discontinuation
Change from baseline in ctDNA levels; Change from baseline in PD markers in paired biopsies
First 7 cycles (each cycle is 28 days) and at study discontinuation
Changes in fasting blood glucose
Time Frame: Approximately every week in Cycle 1 and Cycle 2 (4-week cycle), every 2 weeks in Cycles 3-6 (4-week cycle), and every cycle through end of treatment (4-week cycles), approximately 24 months
Measured by fasting blood glucose
Approximately every week in Cycle 1 and Cycle 2 (4-week cycle), every 2 weeks in Cycles 3-6 (4-week cycle), and every cycle through end of treatment (4-week cycles), approximately 24 months
Changes in longitudinal glucose metabolism (All Phases)
Time Frame: Approximately every cycle (4-week cycles) until study discontinuation, approximately 24 months
Measured by HbA1c
Approximately every cycle (4-week cycles) until study discontinuation, approximately 24 months
Assess preliminary efficacy of RGT-490 monotherapy in dose escalation and Phase 1b
Time Frame: Approximately every 8 weeks until progressive disease, approximately 12 months
Objective response rate (ORR) based on RECIST v1.1
Approximately every 8 weeks until progressive disease, approximately 12 months
Evaluate additional measures of efficacy of RGT-490
Time Frame: Approximately every 8 weeks until progressive disease, approximately 36 months
Duration of response (DoR) according to RECIST v1.1
Approximately every 8 weeks until progressive disease, approximately 36 months
Evaluate additional measures of efficacy of RGT-490
Time Frame: Approximately every 8 weeks until progressive disease, approximately 36 months
Progression free survival (PFS) according to RECIST v1.1
Approximately every 8 weeks until progressive disease, approximately 36 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Regor Pharmaceuticals Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

April 1, 2028

Study Completion (Estimated)

October 1, 2028

Study Registration Dates

First Submitted

March 31, 2026

First Submitted That Met QC Criteria

April 6, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

April 21, 2026

Last Update Submitted That Met QC Criteria

April 16, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RGT-490-101

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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