Sapanisertib and Serabelisib (PIKTOR) in Various Combinations in Patients With HR+/HER2- Advanced/Metastatic Breast Cancer

Open-Label Umbrella Study to Evaluate Safety and Efficacy of Sapanisertib and Serabelisib (PIKTOR) in Various Combinations in Patients With HR+/HER2- Advanced or Metastatic Breast Cancer

Sapanisertib and Serabelisib (PIKTOR) in Various Combinations in Patients With HR+/HER2- Advanced/Metastatic Breast Cancer (NCT07558733) is a Phase 1 / Phase 2 interventional studying HR+ HER2- Breast Cancer, sponsored by Faeth Therapeutics. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For HR+ HER2- Breast Cancer, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 32 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: - diagnosed by tissue sample (biopsy-confirmed) diagnosis of HR+/HER2- breast cancer. - Documented evidence of advanced or recurrent disease that is not amenable to surgery/radiation for curative intent. - Participant has received at least one previous cancer treatment that works throughout the body (like chemotherapy). - At least 1 measurable or evaluable target lesion according to RECIST v1.1 - Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1 at Screening. - Non-pregnant, non-lactating females who are postmenopausal, surgically sterile or who agree to use effective contraceptive methods. Who Should NOT Join This Trial: - Participants with triple-negative breast cancer. - Participants with cancer that has spread to the brain are not eligible, unless they have completed local therapy and have discontinued the use of corticosteroids for this indication for at least 4 weeks before starting treatment in this study. - Active malignancy (except for breast cancer, definitively treated in-situ carcinomas \[e.g., breast, cervix, bladder\], or basal or squamous cell carcinoma of the skin) within the past 24 months prior to treatment. Fully resected localized malignancies are eligible. - Gastric feeding tube (gastrostomy tube), gastrointestinal malabsorption, gastrointestinal anastomosis, bowel obstruction, or any other condition that might affect the absorption of study treatment. - Significant cardiovascular impairment. - Active, uncontrolled infection. - Concurrent participation in another therapeutic clinical trial. - Prior radiation therapy within 21 days prior to start of study treatment. - Participants who have received a prior PI3K, AKT, mTORC1/2, or dual PI3K/mTOR inhibitor. ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Histologically confirmed diagnosis of HR+/HER2- breast cancer. * Documented evidence of advanced or recurrent disease that is not amenable to surgery/radiation for curative intent. * Participant has received at least one prior systemic therapy. * At least 1 measurable or evaluable target lesion according to RECIST v1.1 * Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1 at Screening. * Non-pregnant, non-lactating females who are postmenopausal, surgically sterile or who agree to use effective contraceptive methods. Exclusion Criteria: * Participants with triple-negative breast cancer. * Participants with central nervous system metastases are not eligible, unless they have completed local therapy and have discontinued the use of corticosteroids for this indication for at least 4 weeks before starting treatment in this study. * Active malignancy (except for breast cancer, definitively treated in-situ carcinomas \[e.g., breast, cervix, bladder\], or basal or squamous cell carcinoma of the skin) within the past 24 months prior to treatment. Fully resected localized malignancies are eligible. * Gastric feeding tube (gastrostomy tube), gastrointestinal malabsorption, gastrointestinal anastomosis, bowel obstruction, or any other condition that might affect the absorption of study treatment. * Significant cardiovascular impairment. * Active, uncontrolled infection. * Concurrent participation in another therapeutic clinical trial. * Prior radiation therapy within 21 days prior to start of study treatment. * Participants who have received a prior PI3K, AKT, mTORC1/2, or dual PI3K/mTOR inhibitor. * Strong CYP3A4 inhibitors, strong CYP1A2 inhibitors or CYP1A2 inducers, or clinically significant CYP3A4 inducers within 7 days before the first dose of study intervention, or participants who require treatment with strong CYP3A4 inhibitors or inducers during the study. * Prolongation of QTc interval to \>480 ms. * Type 1 or Type 2 diabetes mellitus on insulin.

Treatments Being Tested

DRUG

Serabelisib

Serabelisib is a selective, small molecule inhibitor of PI3Kα.

DRUG

Sapanisertib

Sapanisertib is a small molecule inhibitor of the mammalian mTOR serine/threonine kinase.

DRUG

Fulvestrant

Fulvestrant is a first-in-class SERD.

Locations (3)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

START Los Angeles

Los Angeles, California, United States

Oncology Associates of Oregon

Springfield, Oregon, United States

SCRI Oncology Partners

Nashville, Tennessee, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT07558733), the sponsor (Faeth Therapeutics), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT07558733 clinical trial studying?

The study is a Phase 1b/2, multi-center, open-label, dose escalation trial evaluating the safety and preliminary efficacy of sapanisertib and serabelisib (PIKTOR) with fulvestrant and/or other anticancer therapies in participants with HR+/HER2- advanced/metastatic breast cancer. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT07558733?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT07558733?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT07558733. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT07558733. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.