Esophageal Squamous Cell CarcinomaPhase 1NCT07284186
First-in-Human Study of PLX-61639 in Locally Advanced or Metastatic Solid Tumors
A Phase 1 study testing PLX-61639 in people with Esophageal Squamous Cell Carcinoma and Gastric Adenocarcinoma, run by Plexium, Inc. at 10 sites in United States.
Trial summary
A multicenter, single-arm, first-in-human study to investigate the safety, pharmacokinetics, and preliminary antitumor activity of PLX-61639 in participants with locally advanced or metastatic, relapsed/refractory, SMARCA4-deficient solid tumors who are intolerant of or have failed available, approved therapies. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Esophageal Squamous Cell Carcinoma, Gastric Adenocarcinoma, Gastric Squamous Cell Carcinoma
- What is being tested?
- PLX-61639
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 155 participants
- Where
- 10 sitesUnited States
- Study dates
- 1 Dec 2025to Sep 2030
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Participants with locally advanced or metastatic, relapsed/refractory, solid tumors harboring a SMARCA4 loss-of-function mutation that have progressed on, are intolerant of, or not otherwise candidates for available approved therapies
- Adequate liver bone marrow, coagulation, renal, and cardiopulmonary function
- Measurable disease per RECIST 1.1
- ECOG PS of 0 or 1
Who cannot join
- Germline SMARCA4 mutations
- Known SMARCA2 mutation or loss of expression
- Symptomatic CNS disease
- Prior treatment with another SMARCA2-directed therapy
- History of other malignancies
- Clinically significant heart disease
- Uncontrolled hypertension
- Prolongation of QT interval
Trial locations and contacts
10 sites in 1 country. Contact the study team or a site near you to ask about taking part.
10 sites in 1 country
United States10 sites, 10 recruiting
- Recruiting
Research Site
Boston, Massachusetts, 02114
- Recruiting
Research Site
Cleveland, Ohio, 44106
- Recruiting
Research Site
Duarte, California, 91010
- Recruiting
Research Site
Durham, North Carolina, 27710
- Recruiting
Research Site
Fairfax, Virginia, 22031
- Recruiting
Research Site
New York, New York, 10044
- Recruiting
Research Site
Orange, California, 92868
- Recruiting
Research Site
San Antonio, Texas, 78229
- Recruiting
Research Site
Scottsdale, Arizona, 85258
- Recruiting
Research Site
St Louis, Missouri, 63110
About this study
Official title: A Phase 1, First-in-Human Study of the SMARCA2 Degrader, PLX-61639, in Patients With SMARCA4-Mutated Locally Advanced or Metastatic Solid Tumors
A multicenter, single-arm, first-in-human study to investigate the safety, pharmacokinetics, and preliminary antitumor activity of PLX-61639 in participants with locally advanced or metastatic, relapsed/refractory, SMARCA4-deficient solid tumors who are intolerant of or have failed available, approved therapies.
The study will be conducted in 3 parts: dose escalation (Part 1), dose optimization (Part 2), and cohort expansion (Part 3). Each part of the study will consist of a Screening Phase lasting up to 28 days during which participants will be assessed for eligibility, a Treatment Phase beginning on Cycle 1 Day 1 and consisting of consecutive 28-day cycles, an End of Treatment Visit, and a Post-Treatment Follow-Up Phase.
Participants will receive their assigned dose of PLX-61639 administered orally, once daily until progression/relapse, intolerance, death, or withdrawal from study treatment by the Investigator or participant.
- Conditions
- Esophageal Squamous Cell Carcinoma, Gastric Adenocarcinoma, Gastric Squamous Cell Carcinoma, Gastroesophageal Junction (GEJ) Adenocarcinoma, Metastatic Solid Tumor, Non-Small Cell Lung Carcinoma
- Being tested
- PLX-61639
- Medical subject headings
- Esophageal Squamous Cell Carcinoma, Adenocarcinoma, Neoplasm Metastasis, Carcinoma, Non-Small-Cell Lung, Adenocarcinoma Of Esophagus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PLX-61639Drug
Orally available degrader of SMARCA2
| Study group | Role | What they receive |
|---|---|---|
| PLX-61639 | Experimental | Not described Receives: Drug: PLX-61639 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Treatment Emergent Adverse Events
Measured: From enrollment to 28 days after the last dose of PLX-61639
Dose-Limiting Toxicities
Measured: From enrollment to 28 days after first dose of PLX-61639
Secondary outcomes (9)
Dose reductions due to Adverse Events
Measured: From Day 1 to the end of PLX-61639 treatment, an average of 1 year
Study treatment discontinuations for reasons other than disease progression
Measured: From Day 1 to the end of PLX-61639 treatment, an average of 1 year
Pharmacokinetics of PLX-61639: Cmax
Measured: From Day 1 to Day 15 of Cycle 1 (Part 1 only) (each cycle is 28 days)
Pharmacokinetics of PLX-61639: Tmax
Measured: From Day 1 to Day 15 of Cycle 1 (Part 1 only) (each cycle is 28 days)
Pharmacokinetics of PLX-61639: AUC0-last
Measured: From Day 1 to Day 16 of Cycle 1 (Part 1 only) (each cycle is 28 days)
Radiographic response to PLX-61639
Measured: From Day 1 to the end of PLX-61639 treatment, an average of 1 year
Time to response (TTR) to PLX-61639
Measured: From Day 1 to achievement of partial or complete response, up to 24 weeks
Duration of response (DoR) to PLX-61639
Measured: From first documented partial or complete response to disease progression or death, an average of 1 year
Progression Free Survival (PFS) of PLX-61639
Measured: From Day 1 to disease progression or death, an average of 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Dec 2025
- Study start1 Dec 2025
- Primary completionDec 2029 (estimated)
- Study completionSep 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Esophageal Squamous Cell CarcinomaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Model description
- In Part 1, eligible participants will enroll sequentially in up to 5 escalating PLX-61639 dose cohorts. In Part 2, participants will be randomized 1:1 to 1 of 2 dose levels at or below the maximally tolerated (or administered) dose evaluated during Part 1. In Part 3, additional participants will enroll sequentially to 1 dose level selected from Part 2.
- Masking
- None (open label)
- Enrolment
- 155 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Plexium, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Chief Medical Officer, Study director, Plexium, Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07284186
- Sponsor's protocol ID
- PLX-61639-101
- Status last verified
- Jun 2026
- First submitted
- 20 Nov 2025
- Last updated
- 12 Jun 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1, First-in-Human Study of the SMARCA2 Degrader, PLX-61639, in Patients With SMARCA4-Mutated Locally Advanced or Metastatic Solid Tumors
- ClinicalTrials.gov ID
- NCT07284186
- Acronym / sponsor ID
- PLX-61639-101
- Conditions
- Esophageal Squamous Cell Carcinoma, Gastric Adenocarcinoma, Gastric Squamous Cell Carcinoma, Gastroesophageal Junction (GEJ) Adenocarcinoma, Metastatic Solid Tumor, Non-Small Cell Lung Carcinoma
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 155 participants (estimated)
- Lead sponsor
- Plexium, Inc.Industry (pharma, biotech, devices)
- Study start
- 1 Dec 2025 (actual)
- Primary completion
- Dec 2029 (estimated)
- Study completion
- Sep 2030 (estimated)
- First posted
- 16 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
A multicenter, single-arm, first-in-human study to investigate the safety, pharmacokinetics, and preliminary antitumor activity of PLX-61639 in participants with locally advanced or metastatic, relapsed/refractory, SMARCA4-deficient solid tumors who are intolerant of or have failed available, approved therapies.
The study will be conducted in 3 parts: dose escalation (Part 1), dose optimization (Part 2), and cohort expansion (Part 3). Each part of the study will consist of a Screening Phase lasting up to 28 days during which participants will be assessed for eligibility, a Treatment Phase beginning on Cycle 1 Day 1 and consisting of consecutive 28-day cycles, an End of Treatment Visit, and a Post-Treatment Follow-Up Phase.
Participants will receive their assigned dose of PLX-61639 administered orally, once daily until progression/relapse, intolerance, death, or withdrawal from study treatment by the Investigator or participant.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- In Part 1, eligible participants will enroll sequentially in up to 5 escalating PLX-61639 dose cohorts. In Part 2, participants will be randomized 1:1 to 1 of 2 dose levels at or below the maximally tolerated (or administered) dose evaluated during Part 1. In Part 3, additional participants will enroll sequentially to 1 dose level selected from Part 2.
| Arm | Type | Receives |
|---|---|---|
| PLX-61639 | Experimental | Drug: PLX-61639 |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Participants with locally advanced or metastatic, relapsed/refractory, solid tumors harboring a SMARCA4 loss-of-function mutation that have progressed on, are intolerant of, or not otherwise candidates for available approved therapies
- Adequate liver bone marrow, coagulation, renal, and cardiopulmonary function
- Measurable disease per RECIST 1.1
- ECOG PS of 0 or 1
Key exclusion criteria (8 listed)
- Germline SMARCA4 mutations
- Known SMARCA2 mutation or loss of expression
- Symptomatic CNS disease
- Prior treatment with another SMARCA2-directed therapy
- History of other malignancies
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PLX-61639Orally available degrader of SMARCA2 | Drug | PLX-61639 |
Primary outcome
Treatment Emergent Adverse Events
Time frame: From enrollment to 28 days after the last dose of PLX-61639
Dose-Limiting Toxicities
Time frame: From enrollment to 28 days after first dose of PLX-61639
9 secondary outcomes
Dose reductions due to Adverse Events
Time frame: From Day 1 to the end of PLX-61639 treatment, an average of 1 year
Study treatment discontinuations for reasons other than disease progression
Time frame: From Day 1 to the end of PLX-61639 treatment, an average of 1 year
Pharmacokinetics of PLX-61639: Cmax
Time frame: From Day 1 to Day 15 of Cycle 1 (Part 1 only) (each cycle is 28 days)
Pharmacokinetics of PLX-61639: Tmax
Time frame: From Day 1 to Day 15 of Cycle 1 (Part 1 only) (each cycle is 28 days)
Pharmacokinetics of PLX-61639: AUC0-last
Time frame: From Day 1 to Day 16 of Cycle 1 (Part 1 only) (each cycle is 28 days)
Radiographic response to PLX-61639
Time frame: From Day 1 to the end of PLX-61639 treatment, an average of 1 year
Time to response (TTR) to PLX-61639
Time frame: From Day 1 to achievement of partial or complete response, up to 24 weeks
Duration of response (DoR) to PLX-61639
Time frame: From first documented partial or complete response to disease progression or death, an average of 1 year
Progression Free Survival (PFS) of PLX-61639
Time frame: From Day 1 to disease progression or death, an average of 1 year
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Chief Medical Officer study director
Plexium, Inc.
10 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing PLX-61639 in people with Esophageal Squamous Cell Carcinoma and Gastric Adenocarcinoma, run by Plexium, Inc. at 10 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 12 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 10 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Clinical Operations (619-631-3091, ClinicalTrials@Plexium.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Treatment Emergent Adverse Events (time frame: From enrollment to 28 days after the last dose of PLX-61639). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Jun 2026.