Recruiting
Phase 1/2 Study of ETX-636 in Participants With Advanced Solid Tumors
Phase 1/2, open-label study of ETX-636 in participants with advanced solid tumors
ClinicalTrials.gov IDNCT06993844
PhasePHASE1, PHASE2
Enrollment233
SponsorEnsem Therapeutics
Age18 Years and older
SexALL
Conditions studied
Advanced Solid Tumors, Advanced Breast Cancer
About this study
Phase 1/2, open-label study of ETX-636 in participants with advanced solid tumors
Interventions
- Drug: ETX-636 dose escalation — ETX-636 is a pan-mutant-selective PI3Kα Inhibitor and degrader in the form of an oral tablet that will be taken once per day in 28-day cycles, to evaluate escalating dose levels.
- Drug: ETX-636 dose escalation in combination with fulvestrant — ETX-636 is a pan-mutant-selective PI3Kα Inhibitor and degrader in the form of an oral tablet. ETX-636 will be taken in combination with fulvestrant in 28-day cycles, to evaluate escalating dose levels. EXT-636 is an oral tablet that will be taken once per day. Fulvestrant will be administered as an injection 2 weeks apart in the first 28 days, followed by monthly injections.
- Drug: ETX-636 dose expansion in combination with fulvestrant — ETX-636 is a pan-mutant-selective PI3Kα Inhibitor and degrader in the form of an oral tablet. ETX-636 will be taken in combination with fulvestrant in 28-day cycles, to expand selected dose levels. EXT-636 is an oral tablet that will be taken once per day. Fulvestrant will be administered as an injection 2 weeks apart in the first 28 days, followed by monthly injections.
Primary outcomes
- Evaluate Safety and Tolerability of ETX-636 monotherapy in Part A and ETX-636 plus fulvestrant combination therapy in Part B (First 28 days of treatment)
- Evaluate Safety and Tolerability of ETX-636 monotherapy in Part A and ETX-636 plus fulvestrant combination therapy in Part B (Average of 6 months)
- Select the Recommended Phase 2 Dose(s) (RP2D) in Part B to be further explored in Part C (combination therapy expansion) (Average of 6 months)
- Evaluate efficacy of ETX-636 plus fulvestrant combination therapy at the RP2D(s) in Part C (Average of 6 months)
Eligibility information
Key Inclusion Criteria:
* Metastatic or locally advanced and unresectable solid tumor that has progressed on or after at least one available therapy.
* Tumor harboring an activating PIK3CA mutation detected in either tumor tissue or ctDNA.
* At least 1 measurable lesion or evaluable disease per RECIST v1.1.
* An ECOG performance status score of 0 or 1.
* Adequate organ function.
Additional key inclusion criterion for Parts B and C:
\- Confirmed metastatic or locally advanced HR+/HER2- breast cancer not amenable to surgical resection with curative intent and must have received at least 1 prior CDK4/6 inhibitor and at least 1 prior anti-estrogen therapy.
Key Exclusion Criteria:
* Has history (within ≤2 years before screening) of a solid tumor or hematological malignancy that is histologically distinct from the cancers being studied.
* Has symptomatic brain or spinal metastases or a known or suspected history of untreated or uncontrolled central nervous system (CNS) involvement.
* Has an established diagnosis of diabetes mellitus type 1 or has uncontrolled diabetes mellitus type 2.
* Has received treatment with any local or systemic anticancer therapy or investigational anticancer agent within 14 days prior to start of treatment.
* Has toxicities from previous anticancer therapies that have not resolved to baseline levels with the exception of alopecia and peripheral neuropathy.
* Has had radiotherapy outside the target tumor lesions within 14 days prior to start of treatment.
Study locations
- Hoag Memorial Hospital Presbyterian, Newport Beach, California 92663 United States
- UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California 94158 United States
- Yale University, Yale Cancer Center, New Haven, Connecticut 06520 United States
- Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215 United States
- Dana-Farber Cancer Institute, Boston, Massachusetts 02215 United States
- Carolina BioOncology Institute, Huntersville, North Carolina 28078 United States
- The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 United States
- START, San Antonio, Texas 78229 United States
- NEXT, Fairfax, Virginia 22031 United States
- Fred Hutchinson Cancer Center, Seattle, Washington 98109 United States
Showing 10 of 15 reported sites. See the official listing for all locations.
Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.
Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-11-12.