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Melanoma (Skin)Phase 2NCT03595683

Pembrolizumab and EDP1503 in Advanced Melanoma

A Phase 2 study testing Pembrolizumab and EDP1503 in people with Melanoma (Skin) and Melanoma, run by University of Chicago at 1 site in United States.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
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Trial summary

This study is being done to determine if orally administered EDP1503 will enhance the response to standard immunotherapy treatment (pembrolizumab) in participants with advanced melanoma. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Melanoma (Skin), Melanoma
What is being tested?
Pembrolizumab and EDP1503
Could I receive a placebo?
No, everyone receives an active treatment
How many people
8 participants
Where
1 siteUnited States
Study dates
2 Oct 2018to 31 Jul 2025
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

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

  • Advanced, unresectable or metastatic melanoma
  • Be willing and able to provide written informed consent/assent for the trial.
  • Aged 18 years or older on day of signing informed consent.
  • Have measurable disease based on Response Evaluation Criteria In Solid Tumors (RECIST) 1.1.
  • Be naïve to exposure in the metastatic setting to PD1/L1 antibody for cohort 1 but have had exposure to PD1/L1 (or PD1/L1 combination therapy) in cohort 2. Prior exposure to CTLA4 antibody in the metastatic setting is not allowed for cohort 1 though exposure in the adjuvant setting is allowed for either cohort. To be eligible for cohort 2, and considered refractory to PD1/L1, a patient must have had a restaging exam showing progressive disease at least 90 days following initiation of anti-PD1/L1 as prior therapy.
  • Adjuvant therapy with BRAF-MEK, PD1 or CTLA4 based therapy is allowed. Prior adjuvant BRAF-MEK therapy will fulfill treatment requirement in the metastatic setting. Patients who experience progression of disease during adjuvant PD1 therapy or within 6 months of completing adjuvant PD1 therapy will be considered refractory and thus eligible for cohort 1. Patients with progression to active metastatic disease more than 6 months following completion of adjuvant PD1 therapy will be eligible for cohort 1.
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  • Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale.
  • Demonstrate adequate organ function as defined in Table 1, all screening labs should be performed within 14 days of study initiation.
  • Adequate Organ Function Laboratory Values
  • Absolute neutrophil count (ANC) ≥1,500 /mcL
  • Platelets ≥100,000 / mcL
  • Hemoglobin ≥9 g/dL or ≥5.6 mmol/L without transfusion or EPO dependency (within 7 days of assessment)
  • Serum creatinine OR Measured or calculated creatinine clearance (GFR can also be used in place of creatinine or CrCl) ≤1.5 X upper limit of normal (ULN) OR ≥60 mL/min for subject with creatinine levels > 1.5 X institutional ULN
  • Serum total bilirubin ≤ 1.5 X ULN OR Direct bilirubin ≤ ULN for subjects with total bilirubin levels > 1.5 ULN
  • aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 X ULN OR ≤ 5 X ULN for subjects with liver metastases
  • Albumin >2.5 mg/dL
  • Female subject of childbearing potential should have a negative urine or serum pregnancy within 72 hours prior to receiving the first dose of study medication. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required.
  • Female subjects of childbearing potential must be willing to use an adequate method of contraception for the course of the study through 120 days after the last dose of study medication. [Note: Abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject.]
  • Male subjects of childbearing potential must agree to use an adequate method of contraception starting with the first dose of study therapy through 120 days after the last dose of study therapy. [Note: Abstinence is acceptable if this is the usual lifestyle and preferred contraception for the subject.]

Who cannot join

  • For cohort 2: Has BRAF mutant disease but has not yet received treatment with RAF/MEK inhibitors. This criteria can be met via adjuvant treatment with BRAF-MEK inhibitors
  • Is currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 2 weeks of the first dose.
  • Is currently taking Bifidobacterium based probiotics or is taking pre/pro-biotics regularly.
  • Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose.
  • Has a known history of active Bacillus Tuberculosis (TB)
  • Hypersensitivity to pembrolizumab or any of its excipients.
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  • Has had a prior anti-cancer monoclonal antibody (mAb) within 3 weeks prior to study Day 1 (excluding anti-PD1 antibodies such as pembrolizumab or nivolumab in cohort 2) or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events due to agents administered more than 4 weeks earlier.
  • Has had prior chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events due to a previously administered agent.
  • Note: Subjects with ≤ Grade 2 neuropathy are an exception to this criterion and may qualify for the study.
  • Note: If subject received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting therapy.
  • Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer.
  • Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis. Subjects with previously treated brain metastases may participate provided they are stable (without evidence of progression by imaging for at least four weeks prior to the first dose and any neurologic symptoms have returned to baseline), have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to start of study. This exception does not include carcinomatous meningitis which is excluded regardless of clinical stability.
  • Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive drugs). Replacement therapy (eg., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment.
  • Has known history of, or any evidence of active, non-infectious pneumonitis.
  • Has an active infection requiring antibiotic therapy or has received a course of antibiotics within the previous 2 weeks of starting study treatment.
  • Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the subject's participation for the full duration of the trial, or is not in the best interest of the subject to participate, in the opinion of the treating investigator.
  • Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
  • Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of trial treatment.
  • Has a known history of Human Immunodeficiency Virus (HIV) (HIV 1/2 antibodies).
  • Has known active Hepatitis B or Hepatitis C
  • Has received a live vaccine within 30 days of planned start of study therapy. [Note: Seasonal influenza vaccines for injection are generally inactivated flu vaccines and are allowed; however intranasal influenza vaccines (e.g., Flu-Mist®) are live attenuated vaccines, and are not allowed.]

Trial locations and contacts

1 site in 1 country.

United States1 site

  • University of Chicago Medical Center

    Chicago, Illinois, 60637

Other trials in United States

About this study

Official title: Phase II Dual-Cohort Study Evaluating the Effects of Pembrolizumab in the Presence of Gut Microbiota Modulation With EDP1503 in Advanced Melanoma Naïve or Refractory to Anti-PD1 Antibody

This study is being done to determine if orally administered EDP1503 will enhance the response to standard immunotherapy treatment (pembrolizumab) in participants with advanced melanoma.

The study will involve initial administration of EDP1503 for a run-in period (2 weeks) followed by administration of both EDP1503 (twice daily) and pembrolizumab (every 3 weeks).

Mandatory biopsies are required before starting study treatment and after 2 weeks of EDP1503 dosing.

Being tested
Pembrolizumab, EDP1503
Medical subject headings
Melanoma

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PembrolizumabDrug

    Also called Keytruda

    200 mg given by intravenous (IV) infusion once every 3 weeks.

  • EDP1503Biological

    Taken by mouth twice daily. Each capsule will contain ≥ 7.5x10^10 colony-forming units (CFU).

Study groups in NCT03595683
Study groupRoleWhat they receive
Cohort 1: Anti-PD1 naiveExperimentalParticipants that have not received prior anti-PD1 therapy for their cancer will be enrolled to this arm.
Receives: Drug: Pembrolizumab; Biological: EDP1503
Cohort 2: Anti-PD1 refractoryExperimentalParticipants that have received prior anti-PD1 therapy for their cancer will be enrolled to this arm.
Receives: Drug: Pembrolizumab; Biological: EDP1503

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Response Rate

    For Cohort 1, based on deep response (>80% tumor reduction). Assessed by standard RECIST criteria for Cohort 2 (complete + partial response).

    Measured: 2 years

  2. Number of Participants With EPD1503 Related Adverse Events During the Run in Period

    Assessed by CTCAE v4.0, grade 3 or higher

    Measured: 2 weeks

Secondary outcomes (2)

  1. Progression Free Survival (PFS)

    Time from first dose of either drug until disease progression or death from any cause. Surviving subjects without progression will be censored as of the date of the last negative examination. Estimated using the Kaplan-Meier method

    Measured: 2 years

  2. Number of Participants With Treatment Related Adverse Events During Combination Therapy

    Assessed by CTCAE v4.0, grade 3 or higher

    Measured: 2 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted23 Jul 2018
  2. Study start2 Oct 2018
  3. Primary completion31 Jul 2025
  4. Study completion31 Jul 2025

Why it stopped: Drug supply no longer available.

Resources

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 2
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
8 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03595683
Sponsor's protocol ID
IRB17-0461
Status last verified
Dec 2025
First submitted
19 Jun 2018
Last updated
8 Dec 2025
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Pembrolizumab and EDP1503 in people with Melanoma (Skin) and Melanoma, run by University of Chicago at 1 site 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 19 inclusion and 21 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: stopped early, as of the sponsor's last update on 8 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 8 Dec 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Response Rate (time frame: 2 years). 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?

On the ClinicalTrials.gov record for NCT03595683.

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 8 Dec 2025.

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