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Phase 1/2 Study of ETX-636 for Advanced Solid Tumors

This study is testing a new oral tablet called ETX-636, which is a PI3Kα inhibitor and degrader, for people with advanced solid tumors, including advanced breast cancer. ETX-636 targets specific changes (mutations) in the PIK3CA gene in your tumor. You may receive ETX-636 alone or in combination with fulvestrant, another medication. The main goals are to see how safe ETX-636 is, what side effects it causes, and to find the best dose. To join, you must have advanced solid tumors that have progressed after at least one other treatment, and your tumor must have a PIK3CA mutation. The study is looking for 233 participants, but its current status is unclear.

Study design
This is an open-label, multi-part Phase 1/2 study, meaning both you and your doctors will know which treatment you are receiving. It plans to enroll 233 participants.
What's involved
You will take ETX-636 as an oral tablet once per day in 28-day cycles. There will be a 28-day screening period before treatment begins.
Compensation
Not stated in the trial record.
Follow-up
The study will evaluate safety and tolerability during the first 28 days of treatment and on average for 6 months.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06993844

Phase 1/2 Study of ETX-636 in Participants With Advanced Solid Tumors

Recruiting
PHASE1Ages 18+InterventionalTreatment
Ensem Therapeutics
~233 participants
Updated 2026-06-23 on ClinicalTrials.gov
What's tested:ETX-636 dose escalationETX-636 dose escalation in combination with fulvestrantETX-636 dose expansion in combination with fulvestrant

At a glance

Recruiting sites
15 of 15 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Evaluate Safety and Tolerability of ETX-636 monotherapy in Part A and ETX-636 plus fulvestrant combination therapy in Part B
Measured over First 28 days of treatment
+3 more outcomes measured

Conditions

Advanced Solid Tumors
Advanced Breast Cancer

Explore related trials

Breast CarcinomaCervical CarcinomaEndometrial CarcinomaHead and Neck Squamous Cell CarcinomaMalignant Ovarian NeoplasmSolid NeoplasmPIK3CA Gene

Where it's being run

15 sites across 8 states
China5
California2
Massachusetts2
Texas2
Connecticut1
North Carolina1
Virginia1
Washington1

Who to contact

Janaki Parameswaran, MD
[email protected]
1-617-383-4993
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

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.

Exclusion

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.

What this trial measures

  • Evaluate Safety and Tolerability of ETX-636 monotherapy in Part A and ETX-636 plus fulvestrant combination therapy in Part BFirst 28 days of treatment

    Proportion of participants who experience at least 1 Dose Limiting Toxicity (DLT)

  • Evaluate Safety and Tolerability of ETX-636 monotherapy in Part A and ETX-636 plus fulvestrant combination therapy in Part BAverage of 6 months

    Incidence of AEs, treatment discontinuations due to AEs, changes from baseline in laboratory assessments, ECGs and vital signs.

  • 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

    Safety Parameters as described for primary outcomes

  • Evaluate efficacy of ETX-636 plus fulvestrant combination therapy at the RP2D(s) in Part CAverage of 6 months

    ORR and CBR according to RECIST v1.1