Recruiting
Phase 1
Phase 2

Sapanisertib & Serabelisib

Sponsor:

Faeth Therapeutics

Code:

NCT07558733

Conditions

HR+ HER2- Breast Cancer

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Serabelisib

Sapanisertib

Fulvestrant

Study Details

Brief summary:

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.

Conditions

HR+ HER2- Breast Cancer

Study ID

NCT07558733

Start date

Apr 22, 2026

Status verified date

Apr, 2026

Completion date

May, 2033

Anticipated

Primary completion date

May, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

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.

Study Design

Enrollment

32 participants

Anticipated

Allocation

Non randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Cohort A1 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

Subjects will receive doses of sapanisertib and serabelisib (PIKTOR) administered orally and fulvestrant administered intramuscularly.

experimental: Cohort A2 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

Subjects will receive doses of sapanisertib and serabelisib (PIKTOR) at a higher dose than Cohort A1 administered orally and fulvestrant administered intramuscularly.

Interventions

Serabelisib

Serabelisib is a selective, small molecule inhibitor of PI3Kα.

Sapanisertib

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

Fulvestrant

Fulvestrant is a first-in-class SERD.

Primary outcome measure

  • Safety and tolerability of drugs by assessment of adverse events (AEs) / serious adverse events (SAEs) [ Time Frame: 2 years ]

Central Contacts and Locations

Central contacts

Medical Monitor

(708) 406-9282clinicaltrials@faeththerapeutics.com

Locations

START Los Angeles

Recruiting

Los Angeles, California, United States, 90025

Rocky Mountain Cancer Centers

Recruiting

Lone Tree, Colorado, United States, 80124

Oncology Associates of Oregon

Recruiting

Springfield, Oregon, United States, 97477

SCRI Oncology Partners

Recruiting

Nashville, Tennessee, United States, 37203

Texas Oncology - Central/South

Recruiting

Austin, Texas, United States, 78731

START San Antonio

Recruiting

San Antonio, Texas, United States, 78229

Texas Oncology - San Aantonio

Recruiting

San Antonio, Texas, United States, 78240

More Information

Sponsor

Faeth Therapeutics

Last update posted

Jul 2, 2026

Last verified

Apr, 2026

Keywords

  • Serabelisib
  • Sapanisertib
  • Fulvestrant
  • Palbociclib
  • PI3K
  • mTOR
  • Dual PI3K/mTOR inhibition
  • Genetic Mutation
  • Faslodex
  • SERDs
  • Select Estrogen Receptor Degraders
  • CDK
  • CDK46
  • CDK4-6
  • HER2-
  • HER2 negative
  • HR+
  • HR positive
  • Hormone Receptor Positive
  • Advanced Breast Cancer
  • Metastatic Breast Cancer
  • Recurrent Breast Cancer
  • Breast Cancer
  • Cancer of the breast
  • Carcinoma of the breast
  • Neoplasms, Breast
  • Metabolism
  • Synthetic Lethality
  • Metabolism Programming
  • PIK3CA
  • Oral Medications
  • Antineoplastic agents
  • AKT

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Faeth Therapeutics on 2026-07-02.