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RecruitingPhase 1

FIH Study of RGT-419B Alone and With Endocrine Therapy in HR-Positive, HER2-Negative Advanced/Metastatic Breast Cancer

First-in-Human, Escalating Oral Dose Study of RGT-419B Given Alone and With Endocrine Therapy in Subjects With Hormone Receptor Positive, Human Epidermal Growth Factor Receptor 2 Negative Advanced/Metastatic Breast Cancer

Who can join

As published by the study on ClinicalTrials.gov. "Not stated" means the study hasn't said — ask the study team.

Age
18 Years and older
Sex
All sexes
Healthy volunteers
Not accepted
Compensation
Not stated

Other requirements are listed under Eligibility below. Only the study team can confirm whether you can join.

What to expect

No one can promise a trial will help you personally — that is what the research is trying to find out.

What participation involves

Not stated in the study description — ask the study team about visits and procedures.

Compensation
Not stated
  • Study-related exams and procedures are typically provided at no cost. This is how many trials work in general — confirm the details for this study with the study team.
  • Participants are monitored closely by the research team throughout the study.
  • Some participants may receive access to an investigational treatment, which is still being studied.
  • Your participation helps researchers learn whether this approach could help future patients.

About this study

In plain language

This study tests RGT-419B, a pill, alone or with hormone therapy in people for the first time. It checks safety, side effects, how the body handles the drug, and whether it may help treat breast cancer. It is for adults with hormone-sensitive, HER2-negative breast cancer that cannot be removed by surgery or has spread, and has worsened after a CDK4/6 blocker plus hormone therapy.

This is a phase I, First-in-Human (FIH), open-label study to evaluate the safety, tolerability, pharmacokinetic (PK) profile, and preliminary efficacy of RGT-419B administered orally as monotherapy OR in combination with Hormonal Therapy in subjects with HR+, HER2- locally advanced and unresectable (Stage III) or metastatic (Stage IV) breast cancer whose disease has progressed during prior therapy with an approved CDK4/6i plus hormonal therapy.

Compensation is read from the study's own description and may be missing — always confirm with the study team.

Eligibility

Who can join

  • Age 18 or older, of any sex.
  • Fully active or able to do light work, even if heavy activity is limited.
  • Tests confirm estrogen-sensitive, HER2-negative breast cancer that is stage III and cannot be removed by surgery, or stage IV and has spread to other parts of the body.
  • Have tumors that can be measured and assessed before treatment starts.
  • Cancer worsened after one course of a CDK4/6 blocker (a drug that slows cancer cell growth) plus hormone therapy for cancer that had spread. Treatment must have lasted at least 3 months. One extra course after surgery is allowed, with at least 6 months of treatment before cancer worsened.
  • Cancer worsened after no more than 3 courses of hormone therapy. Prior hormone drugs must have been officially approved. No more than 1 course of chemotherapy for cancer that had spread.
  • Organs work well enough for the study.
  • Able to understand the study and willing to sign a consent form.

Who can't join

  • Cancer has spread to internal organs and is causing severe problems with how they work.
  • Pregnant or planning to become pregnant.
  • Past radiation to more than 25% of the bone marrow, the tissue that makes blood cells; bone marrow that does not work well enough; or serious organ damage.
  • Major surgery, chemotherapy, targeted cancer drugs, experimental drugs, or radiation within 14–28 days before the first study dose.
  • A serious, active health problem that is not well controlled by approved medicines allowed in the study.
  • Past allergic reactions to drugs similar to those used in the study.

Simplified for readability. The official criteria below are what the study team uses.

Official eligibility criteria

Inclusion Criteria: 1. Male or female \>/= 18 years old 2. ECOG Performance Status 0 to 1 3. Subjects must have histologically or cytologically confirmed diagnosis of ER+, HER2- ABC consistent with ASCO CAP guidelines that is locally advanced and unresectable (Stage III) or metastatic (Stage IV) BC. 4. Measurable AND evaluable lesions at baseline per RECIST v1.1. 5. Eligible subjects must meet all of the following criteria: * Progression after receiving 1 line of prior cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) therapy combined with HT in the MBC setting (up to 1 additional line of CDK4/6i is permitted in the post-surgical adjuvant setting); * Subjects must have received therapy for ≥3 months in the MBC setting, or for ≥6 months in the adjuvant setting, prior to progression * Progression after ≤3 lines of prior HT therapy (regardless of whether it is HT alone or in combination with other therapies) * Prior HT combination agents, including SERD, SERM or AI, must have received formal approval by regulatory agency. * ≤ 1 prior line of chemotherapy in the metastatic setting 6. Adequate organ function 7. Ability to understand and the willingness to sign a written informed consent document Exclusion Criteria: 1. Presence of visceral metastases with severe organ dysfunction as evidence by signs and symptoms, laboratory studies, lymphangitic spread and/or rapid progression of disease 2. Pregnant or planning to become pregnant 3. Prior irradiation to \>25% of the bone marrow and/or inadequate bone marrow function or evidence of clinically significant end-organ damage 4. Major surgery, chemotherapy, targeted therapy, experimental agents, or radiation within 14-28 days prior to Cycle 1, Day 1 5. Active, serious medical condition that is not well controlled with locally approved medications allowed by the protocol 6. History of allergic reactions attributed to compounds of similar chemical or biologic composition to the drugs used in the study

Study sites (8)

CA

FL

GA

MA

MO

NY