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

NCT07558733 | Recruiting Phase 1 FDA Drug

• 1 other identifier: FTH-PIK-101
• Study Type: interventional
• Target: 32
• Locations: 1 country
• Sites: 3

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

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

Outcome Measures

Primary Outcomes (1)

• Safety and tolerability of drugs by assessment of adverse events (AEs) / serious adverse events (SAEs)

  Graded according to the National Cancer Institute (NCI CTCAE v5.0).

  2 years

Secondary Outcomes (6)

• Objective Response Rate (ORR)

  Up to 2 years.

• Progression Free Survival (PFS)

  Up to 5 years.

• Progression Free Survival (PFS) at 6 months

  6 months

• Overall Survival (OS)

  Up to 5 years.

• Clinical Benefit Rate (CBR)

  Up to 5 years.

Study Arms (2)

Cohort A1 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

EXPERIMENTAL

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

Drug: Serabelisib; Drug: Sapanisertib; Drug: Fulvestrant

Cohort A2 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

EXPERIMENTAL

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

Drug: Serabelisib; Drug: Sapanisertib; Drug: Fulvestrant

Interventions

Serabelisib DRUG

Serabelisib is a selective, small molecule inhibitor of PI3Kα.

Cohort A1 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant; Cohort A2 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

Sapanisertib DRUG

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

Cohort A1 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant; Cohort A2 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

Fulvestrant DRUG

Fulvestrant is a first-in-class SERD.

Cohort A1 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant; Cohort A2 - Sapanisertib and serabelisib (PIKTOR) with fulvestrant

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Faeth Therapeutics: lead

Study Sites (3)

START Los Angeles

Los Angeles, California, 90025, United States

RECRUITING

Oncology Associates of Oregon

Springfield, Oregon, 97477, United States

RECRUITING

SCRI Oncology Partners

Nashville, Tennessee, 37203, United States

RECRUITING

Related Links

• Related Info

MeSH Terms

Conditions

Breast Neoplasms; Hereditary Sensory and Autonomic Neuropathies

Interventions

serabelisib; sapanisertib; Fulvestrant

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases; Nervous System Malformations; Nervous System Diseases; Heredodegenerative Disorders, Nervous System; Neurodegenerative Diseases; Polyneuropathies; Peripheral Nervous System Diseases; Neuromuscular Diseases; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Genetic Diseases, Inborn

Intervention Hierarchy (Ancestors)

Estradiol; Estrenes; Estranes; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Estradiol Congeners; Gonadal Steroid Hormones; Gonadal Hormones; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists

Central Study Contacts

Medical Monitor

CONTACT

(708) 406-9282; clinicaltrials@faeththerapeutics.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 17, 2026
• First Posted: April 30, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): May 1, 2029
• Study Completion (Estimated): May 1, 2033
• Last Updated: April 30, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (3)