NCT06827236 · BioNTech SE
A Clinical Study to Find the Optimal Dose of an Investigational Treatment Called BNT323 When Used in Combination With Another Investigational Treatment, BNT327, and to Test if That Combination Treatment is Safe and Beneficial for Patients With Advanced Breast Cancer
What this study is about
This is a Phase I/II, multi-site, where both patients and doctors know the treatment given, two-part study designed to evaluate the effectiveness, safety, optimized dose and contribution of components of BNT323 in combination with BNT327 in participants with hormone receptor-positive (HR+) or hormone receptor-negative (HR-), Human epidermal growth factor receptor (HER)2-positive, HER2-low (immunohistochemistry \[IHC\] 1+ or IHC 2+/in situ hybridization -), HER2-ultralow (IHC 0, with membrane staining) or HER2-null breast cancer (BC), or triple-n
View original scientific description
This is a Phase I/II, multi-site, open-label, two-part study designed to evaluate the efficacy, safety, optimized dose and contribution of components of BNT323 in combination with BNT327 in participants with hormone receptor-positive (HR+) or hormone receptor-negative (HR-), Human epidermal growth factor receptor (HER)2-positive, HER2-low (immunohistochemistry \[IHC\] 1+ or IHC 2+/in situ hybridization -), HER2-ultralow (IHC 0, with membrane staining) or HER2-null breast cancer (BC), or triple-n
Interventions
DRUG
BNT323
Intravenous infusion
DRUG
BNT327
Intravenous infusion
Primary outcome measures
Part 1 - Occurrence of dose limiting toxicities (DLTs)
Time frame: During the DLT evaluation period (Cycle 1), i.e., the time of initiation of the first dose of investigational medicinal product (IMP) up to 21 days
By dose level.
Occurrence of Treatment-emergent adverse events (TEAEs), Grade ≥3 TEAEs, serious adverse events (SAEs), treatment-related TEAEs, treatment-related Grade ≥3 TEAEs, and treatment-related SAEs
Time frame: From the time of initiation of the first dose of IMP to 90 days after the last IMP dose
In Part 1 by dose level. In Part 2 by cohort and arm.
Occurrence of dose interruption, reduction, and discontinuation due to TEAEs
Time frame: From the time of initiation of the first dose of IMP to 90 days after the last IMP dose
In Part 1 by dose level. In Part 2 by cohort and arm.
Part 2 - Objective response rate (ORR)
Time frame: From the time of initiation of the first dose of IMP to last tumor assessment scan, i.e., up to 36 months.
ORR defined as the proportion of participants in whom a confirmed complete response (CR) or partial response (PR) (per Response Evaluation Criteria in Solid Tumors version 1.1 \[RECIST v1.1\] based on the investigator's assessment) is observed as best overall response. By cohort and arm.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- (applicable to all participants and all parts unless otherwise specified):
- Have pathologically documented BC that:
- Is locally advanced, unresectable or metastatic.
- Has a confirmed HER2 status as determined by the local laboratory (Part 1, Part 2 Cohorts 2 and 4) or the central laboratory (Part 2, Cohorts 1 and 3) from the most recently collected pre-randomization tumor sample.
- Has a documented history of HER2 expression consistent with the subgroup definitions (i.e., HER2-low, HER2-ultralow, HER2-null, HER2-positive, or TNBC) as per current American Society of Clinical Oncology/College of American Pathologists guidelines.
- Have measurable disease defined by RECIST v1.1.
- Has left ventricular ejection fraction ≥55% by either echocardiography or multi-gated acquisition (scanning) within 28 days before randomization/enrollment. Key
Exclusion criteria
- Have history of small bowel obstruction requiring hospitalization within the past 3 months pri
Where
- Beverly Hills, California
- Newport Beach, California
- Port Saint Lucie, Florida
- Athens, Georgia
- Atlanta, Georgia
- Detroit, Michigan
- Grand Rapids, Michigan
- Kansas City, Missouri
- St Louis, Missouri
- Basking Ridge, New Jersey
- Florham Park, New Jersey
- Middletown, New Jersey
And 6 more locations — see the full list below.
Collaborators
DualityBio Inc., BioNTech (Shanghai) Pharmaceuticals Co., Ltd.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 23, 2026 · Source of record for eligibility and locations