Assessing the safety of ES2B-C001 in patients with HER2 positive metastatic breast cancer.

A First-In-Human Phase I, Open-Label, Dose-Escalating Trial to Assess the Safety, Tolerability and Immunogenicity/Preliminary Antitumor Activity of ES2B-C001 With or Without [Adjuvant] in HER2-expressing Metastatic Breast Cancer

Phase 1 Interventional ExpreS2ion Biotechnologies · NCT06746688

This study is testing a new drug called ES2B-C001 to see if it's safe for people with HER2-positive metastatic breast cancer.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years and up
SexAll
SponsorExpreS2ion Biotechnologies Industry-sponsored
Drugs / interventionschemotherapy, prednisone
Locations3 sites (Graz and 2 other locations)
Trial IDNCT06746688 on ClinicalTrials.gov

What this trial studies

This is a first-in-human, phase I, open-label, dose-escalating trial designed to evaluate the safety and tolerability of the investigational drug ES2B-C001, administered with or without an adjuvant, in patients diagnosed with HER2-positive metastatic breast cancer. The study aims to determine the appropriate dosing and monitor any adverse effects in participants. Eligible patients will be closely monitored for their response to the treatment and any potential side effects throughout the trial.

Who should consider this trial

Good fit: Ideal candidates for this study are adults aged 18 and older with a diagnosis of HER2-positive metastatic or locally advanced inoperable breast cancer.

Not a fit: Patients who are currently undergoing intravenous chemotherapy or have planned chemotherapy regimens may not benefit from this study.

Why it matters

Potential benefit: If successful, this trial could provide a new treatment option for patients with HER2-positive metastatic breast cancer.

How similar studies have performed: Other studies have shown promise in targeting HER2-positive breast cancer, but this specific approach with ES2B-C001 is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients aged ≥18 years at screening visit.
* Diagnosis of HER2-expressing locally advanced, unresectable, or metastatic BC, with HER2 IHC level 1+, 2+ (either FISH negative or positive), or IHC level 3+, after undergoing 2-3 lines of anticancer therapy.
* Life expectancy of at least 3 months.
* ECOG performance status 0-2.
* Patients have adequate bone marrow, kidney, liver, heart, and lung function without clinically significant laboratory parameters as judged by the investigator.
* 12-lead ECG without clinically significant abnormalities and no LBBB, QRS duration \>140ms, or evidence of prior infarction.
* Recovered from side effects, adverse reactions, or adverse events due to prior therapy and/or surgery; any residual toxicities and toxicities related to current anticancer treatment must be ≤ Grade 2, except for alopecia, neuropathy or lymphoedema.
* If female, non-pregnant, postmenopausal, or practicing reliable contraception.
* If male, sterilized or using reliable contraception.

Exclusion Criteria:

* Any planned intravenous chemotherapy regimens or check point inhibitors, or previous therapy with those agents during the past 1 month and the patients are neutropenic. Maintenance therapy with a stable dose of HER2-directed mAbs or treatment with antibody drug conjugates (ADCs) for metastatic BC is allowed at the discretion of the treating physician.
* Symptomatic CNS metastatic disease requiring treatment with high dose steroids (i.e., above 10 mg of prednisone or equivalent) within 14 days prior to first administration of ES2B-C001 (with or without adjuvant).
* Concurrent or recent (within 21 days or 5 half-lives) involvement in any other clinical trial with an investigational drug, device, or other experimental intervention.
* Concomitant severe or uncontrolled underlying medical and/or mental disease unrelated to the tumor, which in the opinion of the investigator is likely to compromise patient safety and affect the trial's outcome.
* Previous documented coronary artery disease or congestive heart failure (\>NYHA II).
* Echocardiography with LVEF \<55%.
* Uncontrolled hypertension.
* Active, known, or suspected autoimmune disease, except thyroid conditions sufficiently controlled on thyroid hormone therapy, and controlled insulin dependent diabetes.
* Necessity for long-term immunosuppression (≤ 4 mg dexamethasone may be used transiently).
* Systemic infection requiring intravenous antibiotics within 14 days before dosing.
* Chronic use of anti-viral agents, except for human immunodeficiency virus (HIV) or hepatitis B or C virus (HBV, HCV) treatments.
* History of severe hypersensitivity reactions to any of the trial drug components.
* Has received a live or live-attenuated vaccine within 30 days prior to the first dose of trial treatment. Note: Administration of inactivated or recombinant vaccines/killed vaccines are allowed.
* Birthmarks, tattoos, wounds, or skin conditions on deltoid region/buttocks that may obscure the assessment of injection site reactions.
* Female patients who are pregnant, or lactating.
* Any infection (including SARS-CoV-2), that in the opinion of the investigator would, upon inclusion in the trial, lead to potentially harming patients' safety or integrity.

Where this trial is running

Graz and 2 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Breast CancerBreast Cancer Metastaticbreast cancerMBCmetastatic breast cancer
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.