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Breast CancerPhase 1NCT06299124

A Phase I Study of RGT-419B in Patients With HR-Positive, HER2-Negative Advanced Breast Cancer or Other Solid Tumors

A Phase 1 study testing RGT-419B in people with Breast Cancer and Advanced Solid Tumor, run by Regor Pharmaceuticals Inc. at 1 site in China.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

This is a Phase 1 dose escalation and dose expansion phase I study to evaluate the safety, tolerability, pharmacokinetic profile and preliminary efficacy of RGT-419B as monotherapy in Chinese patients with HR+/HER2- advanced/metastatic breast cancer and other advanced solid tumors. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Breast Cancer, Advanced Solid Tumor
What is being tested?
RGT-419B
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
40 participants
Where
1 siteChina
Study dates
17 Apr 2023to 30 Dec 2026
Phase
Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Male or female ≥ 18 years of age
  • Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
  • Subjects with pathologically confirmed advanced solid tumors who have failed standard-of-care therapy, or have no standard-of-care therapy available, or are currently not eligible for standard-of-care therapy; Subjects with HR+/ HER2- advanced or metastatic breast cancer are preferred.
  • Estimated life expectancy of at least 12 weeks

Who cannot join

  • Presence of visceral metastases with severe organ dysfunction
  • Known active hepatitis B or C infection
  • Prior irradiation to >25% of the bone marrow and/or inadequate bone marrow function or evidence of clinicallysignificant end-organ damage
  • History of allergic reactions attributed to compounds of similar chemical or biologic composition to the drugs usedin the study

Trial locations and contacts

1 site in 1 country.

China1 site
  • Fudan University Shanghai Cancer Center

    Shanghai, Shanghai Municipality, 200032

Other trials in China

About this study

Official title: A Phase I Study Evaluating Safety and Tolerability of RGT-419B Monotherapy in Chinese Patients With Hormone Receptor Positive, Human Epidermal Growth Factor Receptor 2 Negative Advanced/Metastatic Breast Cancer or Other Solid Tumors

This is a Phase 1 dose escalation and dose expansion phase I study to evaluate the safety, tolerability, pharmacokinetic profile and preliminary efficacy of RGT-419B as monotherapy in Chinese patients with HR+/HER2- advanced/metastatic breast cancer and other advanced solid tumors.

Being tested
RGT-419B
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • RGT-419BDrug

    Also called Active drug

    RGT-419B will be administered orally

Study groups in NCT06299124
Study groupRoleWhat they receive
RGT-419B monotherapyExperimentalDose escalation and dose expansion of RGT-419B monotherapy
Receives: Drug: RGT-419B

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Safety & Tolerability - Number of subjects with Dose-Limiting Toxicities (DLTs) at each cohort dose level

    Number of subjects who have a confirmed DLT at each cohort dose level during the first 28-day cycle of RGT-419B treatment.

    Measured: 4 weeks (1 cycle)

Secondary outcomes (9)
  1. Safety & Tolerability - Incidence, Severity, and Causality of all Treatment Emergent Adverse Events (TEAEs)

    Incidence, severity, and causality of all TEAEs will be assessed for all patients participating from Day 1 dosing through end of study.

    Measured: through study completion, an average of 1 year

  2. Day 1 and steady-state pharmacokinetics(PK) assessment of RGT-419B and major metabolites - Cmax

    Measured: 4 weeks (1 cycle)

  3. Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Area Under Concentration-TimeCurve to Infinity (AUC0-inf)

    Measured: 4 weeks (1 cycle)

  4. Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Plasma Decay Half-Life (t1/2)

    Measured: 4 weeks (1 cycle)

  5. Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Time to Reach Maximum ObservedPlasma Concentration (Tmax)

    Measured: 4 weeks (1 cycle)

  6. Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Accumulation rate after multipledoses

    Measured: 4 weeks (1 cycle)

  7. Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Cumulative urinary excretion

    Measured: 4 weeks (1 cycle)

  8. Tumor Response assessed by Investigator according to RECIST v1.1

    Measured: through study completion, an average of 1 year

  9. QTc Interval - Changes in corrected QT interval

    Number of subjects with a clinically significant increase from baseline in corrected QT (QTc) interval onrepeated ECGs

    Measured: through study completion, an average of 1 year

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted7 Mar 2024
  2. Study start17 Apr 2023
  3. Primary completion30 Dec 2026 (estimated)
  4. Study completion30 Dec 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
40 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06299124
Sponsor's protocol ID
RGT-419B-102
Status last verified
Aug 2026
First submitted
1 Mar 2024
Last updated
27 Aug 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing RGT-419B in people with Breast Cancer and Advanced Solid Tumor, run by Regor Pharmaceuticals Inc. at 1 site in China.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 27 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Safety & Tolerability - Number of subjects with Dose-Limiting Toxicities (DLTs) at each cohort dose level (time frame: 4 weeks (1 cycle)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Aug 2026.

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