A First-in-human, Clinical Trial Assessing the Safety of ES2B-C001-S01 With or Without [Adjuvant] in Patients With HER2 Expressing Metastatic Breast Cancer.

Phase 1

Recruiting

• Conditions: Breast Cancer; Breast Cancer Metastatic
• Interventions: Biological: ES2B-C001; Other: ISA 51 VD

• Registration Number: NCT06746688
• Lead Sponsor: ExpreS2ion Biotechnologies

Brief Summary

The trial is a first-in-human, phase I, open-label, dose-escalating trial to assess the safety and tolerability of ES2B-C001 combined with or without \[adjuvant\], in patients with human epidermal growth factor receptor 2 (HER2) expressing metastatic breast cancer.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-12-12
• Study First Submitted QC: 2024-12-17
• Study First Posted: 2024-12-24
• Study Start: 2025-06-03
• Status Verified: 2025-08
• Last Update Submitted: 2025-08-21
• Last Update Posted: 2025-08-28
• Primary Completion: 2026-03
• Study Completion: 2026-03-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 27

Inclusion Criteria

• Patients aged ≥18 years at screening visit.
• Diagnosis of HER2-positive metastatic or locally advanced inoperable breast cancer (MBC).
• 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 not neutropenic. For MBC maintenance therapy with a stable dose of HER2-directed mAbs or treatment with antibody drug conjugates (ADCs) at the discretion of the treating physician is allowed.
• 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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Cohort C1: 50µg ES2B-C001 with [adjuvant]	ES2B-C001	-
Cohort C1: 50µg ES2B-C001 with [adjuvant]	ISA 51 VD	-
Cohort C2: 150µg ES2B-C001 with [adjuvant]	ES2B-C001	-
Cohort C2: 150µg ES2B-C001 with [adjuvant]	ISA 51 VD	-
Cohort C3: 450µg ES2B-C001 with [adjuvant]	ES2B-C001	-
Cohort C3: 450µg ES2B-C001 with [adjuvant]	ISA 51 VD	-

Primary Outcome Measures

Name	Time	Method
To determine the safety, tolerability, maximum tolerated dose (MTD) for ES2B-C001 alone or in combination with [adjuvant].	From enrolment to the end of study at week 18	* Nature and frequency of dose-limiting toxicities (DLTs).; * Incidence, nature and severity of AEs graded according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v5.0.; * Incidence, nature and severity of injection site reactions according to FDA Guidance on Toxicity Grading Scales in Vaccine Trials (FDA, 2007).

Secondary Outcome Measures

Name	Time	Method
To investigate the immunogenicity of ES2B-C001 alone or in combination with [adjuvant].	From enrolment to the end of study at week 18	Immunogenicity as humoral immune response: Optional: Isotyping of anti-HER2 Immunoglobulins in selected sera (e.g. IgM, IgG (IgG1-4), IgD, IgE, IgA).

Trial Locations

Locations (1)

Medical University Of Vienna; 🇦🇹 Vienna, Austria