First-in-human, Phase 1 Study of a Self-amplifying RNA Vaccine (ITI-5000) Alone or in Combination With Pembrolizumab in Stage II-- III Triple Negative Breast Cancer Following Standard Therapy ( VITAL-TNBC ) (VITAL-TNBC)

June 11, 2026 updated by: Immunomic Therapeutics, Inc.

A Phase 1, Multicenter, Open-label, First-in-Human Study of ITI-5000 (Self-Amplifying RNA Vaccine) Alone and in Combination With Pembrolizumab in Participants With Stage II-III Triple-Negative Breast Cancer (TNBC) Who Have Completed Standard Curative Intent Therapy (VITAL-TNBC Study)

This study tests an investigational cancer vaccine called ITI-5000 in people who have completed standard treatment for early-stage triple-negative breast cancer (TNBC).

ITI-5000 is a self-amplifying RNA (saRNA) vaccine that instructs the immune system to recognize and attack cancer cells expressing two proteins found on TNBC cells-HERV-K and CT83-fused with a molecule called LAMP-1 that helps the immune system respond more strongly. The vaccine is delivered inside lipid nanoparticles (LNPs), similar to other approved mRNA vaccines.

The study has two parts:

  • Part A: Participants receive ITI-5000 alone at one of two dose levels (1 µg or 10 µg), given as an injection into the upper arm muscle every 28 days for 3 doses total. The goal is to find the safest dose.
  • Part B: Participants receive ITI-5000 at the best dose identified in Part A, combined with an approved immunotherapy drug called pembrolizumab (Keytruda®), every 21 days for 3 doses total.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a Phase 1, first-in-human (FIH), multicenter, open-label, two-part, ascending-dose study . Part A evaluates ITI-5000 as a single agent using a modified 3+3 dose-escalation design across two sequential cohorts:

  • Cohort 1: 1 µg (low dose) per vaccination
  • Cohort 2: 10 µg (high dose) per vaccination

Each cohort begins with a sentinel participant monitored for 28 days after Vaccination #1 before additional participants are enrolled. The dose-limiting toxicity (DLT) observation window is Day 1-28 following Vaccination #1. If ≤1/6 participants experience a DLT, the dose is deemed tolerable and the cohort expands to further characterize safety and immunogenicity. The Safety Review Committee (SRC) reviews safety data between cohorts. After participants complete Part A, without dose-limiting toxicity, Part B will commence. Part B participants will receive ITI-5000 (dose selected after Part A) in combination with pembrolizumab. Pembrolizumab is administered per its FDA-approved label at either:

  • 200 mg intravenously every 3 weeks (Q3W), or
  • 400 mg intravenously every 6 weeks (Q6W)

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age: Adults aged 18 years or over.
  • Consent: Provided a signed and dated informed consent form (ICF).
  • Diagnosis: Histologically confirmed stage 2-3 triple-negative breast cancer (TNBC), defined as HER2-negative, ER-negative, and PgR-negative by immunohistochemistry. BRCA mutations are allowed.
  • Prior Treatment: Completed all planned standard therapy (surgery, chemotherapy, radiation, and/or pembrolizumab as applicable) and be within 36 months of definitive surgery.
  • Performance Status: ECOG performance status of 0 or 1.
  • Organ Function: Adequate organ function at baseline (hematology, biochemistry, etc.).
  • Cardiac Function: No significant ischemic heart disease or myocardial infarction within 3 months before vaccination #1; QTc ≤470 msec for females or ≤450 msec for males.
  • Pregnancy: Women of childbearing potential must have a negative serum pregnancy test within 3 days before vaccination #1 and agree to use highly effective contraception during the study and for 123 (Part A) or 137 (Part B) days after last study drug.
  • Compliance: Able to attend required study visits and follow-up.
  • Understanding: Able to understand and provide signed informed consent per IRB/IEC guidelines.
  • Vaccinations: Agrees not to receive routine vaccinations until at least 30 days after the last study vaccine.
  • Alternative Therapies: Agrees not to use alternative therapies from the time of informed consent through 30 days following vaccination #3.

Exclusion Criteria:

  • Part B only: Discontinued prior treatment with an immune checkpoint inhibitor (ICI) due to immune-related adverse events (irAEs).
  • Recent Surgery/Therapy: Major surgery within 4 weeks before vaccination #1 or received cancer-directed therapy or investigational drug/device within 4 weeks or 5 half-lives before vaccination #1.
  • Part B only: Received other PD-1/PD-L1 inhibitors (besides pembrolizumab) without proper washout.
  • Toxicities: Unresolved toxicities from prior immunotherapy or chemotherapy (must be ≤ Grade 1 or baseline, or deemed irreversible and not worsened by immunotherapy).
  • Medical Illness: Significant medical illness, underlying health condition, or abnormal laboratory finding increasing risk.
  • Autoimmune Disease: Active autoimmune disease requiring immunosuppressive treatment within the last year.
  • Pregnancy/Lactation: Female participants trying to conceive, pregnant, or lactating.
  • Positive Pregnancy Test: Positive serum pregnancy test at screening or positive urine test at baseline.
  • Other Trials: Concurrent participation in any other interventional clinical trial.
  • Allergies: Known allergies to any components of the study vaccine.
  • Anaphylaxis: History of anaphylaxis requiring medical intervention (including severe reactions to other mRNA vaccines).
  • Cardiac History: History of stroke, transient ischemic attack, unstable angina, or myocardial infarction within 3 months prior to first dose.
  • Myocarditis/Pericarditis: History of myocarditis or pericarditis.
  • Heart Failure: Symptomatic congestive heart failure (NYHA Class III or IV), significant arrhythmia, or LVEF <45%.
  • QT Risk: History of risk factors for torsade de pointes or use of QT-prolonging medications.
  • Vaccines: Received mRNA or live virus vaccine within 28 days of planned vaccination #1 (flu and COVID boosters prohibited in that window).
  • Prior Malignancy: Prior malignancy except adequately treated basal/squamous cell skin cancer, in situ cervical cancer, or disease-free for ≥3 years.
  • Organ Transplant: History of organ transplant requiring immunosuppression; unstable HIV/AIDS.
  • Hepatitis: Known active hepatitis B or C.
  • Compliance: Unable or unwilling to comply with study schedule/procedures.
  • Injection/Blood Draw: Contraindication to IM injections or blood draws.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arm 1 - Part A, Cohort 1 (ITI-5000 1 µg Monotherapy)
Participants receive ITI-5000 1 µg as an intramuscular injection every 28 days for 3 doses (Days 1, 29-36, 57-64).
Biological: ITI-5000 TNBC Vaccine
For Arms 1 and 2, Participants receive ITI-5000 at two different doses for Part A. Cohort 1 will receive 1 ug of the vaccine. Cohort two, will receive 10 ug of the ITI-5000 Vaccine if the 1 ug dose is tolerated.
Experimental: Arm 2 - Part A, Cohort 2 (ITI-5000 10 ug Monotherapy)
Participants receive ITI-5000 10 µg as an intramuscular injection every 28 days for 3 doses (Days 1, 29-36, 57-64).
Biological: ITI-5000 TNBC Vaccine
For Arms 1 and 2, Participants receive ITI-5000 at two different doses for Part A. Cohort 1 will receive 1 ug of the vaccine. Cohort two, will receive 10 ug of the ITI-5000 Vaccine if the 1 ug dose is tolerated.
Experimental: Arm 3 - Part B (ITI-5000 MTD + Pembrolizumab Combination)
Participants receive ITI-5000 at the MTD (determined in Part A) as an injection every 21 days for 3 doses, plus pembrolizumab 200 mg IV Q3W or 400 mg IV Q6W per FDA-approved label.
Drug: ITI-5000 TNBC Vaccine + Pembrolizumab
Participants will receive ITI-5000 TNBC vaccine at the MTD (determined in Part A) as an intramuscular injection every 21 days for 3 doses, plus pembrolizumab 200 mg IV Q3W or 400 mg IV Q6W per FDA-approved label.
Other Names:
  • Pembrolizumab

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Part A: To establish the dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD) of ITI-5000 and to characterize the safety and tolerability of ITI-5000 administered as a single agent. Part B: same as Part A but in combination with Pembrolizumab
Time Frame: From enrollment to end of treatment at 6 months
From enrollment to end of treatment at 6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Safety and Tolerability of ITI-5000 when administered in combination with pembrolizumab.
Time Frame: From enrollment to end of treatment at 12 months
The secondary outcome measures in this study focus on evaluating the safety and tolerability of ITI-5000 when administered in combination with pembrolizumab (Part B). Specifically, these measures include the incidence and severity of dose-limiting toxicities (DLTs), treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), treatment-related TEAEs, adverse events of special interest (AESIs), and abnormal laboratory parameters, vital signs, and electrocardiograms (ECGs) within 21 days after the first vaccination in Part B
From enrollment to end of treatment at 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Immunomic Therapeutics, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

February 1, 2028

Study Completion (Estimated)

August 1, 2028

Study Registration Dates

First Submitted

June 11, 2026

First Submitted That Met QC Criteria

June 11, 2026

First Posted (Actual)

June 17, 2026

Study Record Updates

Last Update Posted (Actual)

June 17, 2026

Last Update Submitted That Met QC Criteria

June 11, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 5000-01-TNBC-P1

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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