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Taking people in FrancePhase 1/2

Tests two investigational drugs together in advanced breast cancer

Tests BNT323 with BNT327 in adults with advanced breast cancer.

Key facts

Who runs it
BioNTech SE
Where
Besançon, Dijon, Le Mans, Saint-Herblain Cedex, and Toulouse Cedex 9, FranceSee the 5 sitesAlso in 10 other countries, 80 sites
Registry title
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
Status
Recruiting
Phase
Phase 1/2
People taking part
380 people, planned
Started
23 Apr 2025
Expected to end
Aug 2029
Type of study
Interventional, 8 groups
Treatments tested
  • BNT323
  • BNT327
Record updated
10 November 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with advanced breast cancer that has spread or cannot be removed by surgery. It tests two investigational drugs, BNT323 and BNT327, together.

Age
18 years or older
Sex
All sexes can join.
Disease stage
Breast cancer that is locally advanced, cannot be removed by surgery, or has spread (metastatic). The cancer must be measurable on scans (RECIST v1.1). HER2 status must be confirmed (HER2-positive, HER2-low, HER2-ultralow, HER2-null) or the cancer is triple-negative.
Earlier treatment
People who had topoisomerase I inhibitors (such as trastuzumab deruxtecan), BNT323, or a PD-L1/VEGF bispecific antibody before cannot join. Earlier PD-1/VEGF bispecific antibodies, PD-1/PD-L1 inhibitors or anti-VEGF therapies are allowed.
Biomarker or test result
HER2 status must be confirmed by a lab. Heart pumping strength (left ventricular ejection fraction) must be 55% or higher.

Main reasons for not taking part

  • Small bowel obstruction needing hospital care in the past 3 months
  • Uncontrolled fluid around the lungs, belly or heart that needs drainage
  • Past or current lung inflammation (interstitial lung disease/pneumonitis) needing steroids
  • Uncontrolled other illness that would limit following the study or raise the risk of side effects
  • Immune-boosting or immune-suppressing drugs within 4 weeks, or steroids above 10 mg/day of prednisone within 3 weeks

The registry criteria, word for word

Show all 9 criteriaShow less

Who can take part

  • Have pathologically documented BC that:; Is locally advanced, unresectable or metastatic; Has a confirmed HER2 status as determined by the local laboratory as standard of care testing prior to study screening (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

Who cannot take part

  • Have history of small bowel obstruction requiring hospitalization within the past 3 months prior to the first dose of IMP
  • Have clinically uncontrolled pleural effusion, ascites or pericardial effusion requiring drainage, peritoneal shunt, or cell-free concentrated ascites reinfusion therapy within 2 weeks prior to randomization/enrollment
  • Had prior treatment with topoisomerase I inhibitors, including antibody-drug conjugates with topoisomerase I inhibitor payloads such as trastuzumab deruxtecan
  • Have received any of the following therapies or drugs prior to the initiation of the study:; Participants who have received prior treatment with BNT323; Participants who received prior treatment with a programmed death-ligand 1 (PD-L1) / vascular endothelial growth factor (VEGF) bispecific antibody. Note: Prior treatment with programmed death 1 (PD-1)/VEGF bispecific antibodies, PD-1/PD-L1 inhibitors or anti-VEGF therapies are permitted; Have received other systemic immunostimulatory agents or immunosuppressive therapies (such as interferon-α, interleukin-2, or methotrexate) within 4 weeks prior to the initiation of study treatment or are within five half-lives of the treatment drug (whichever is longer). Exception: excluding local, intranasal, intraocular, intra-articular or inhaled corticosteroids, short term use (≤7 days) of corticosteroids for prophylaxis (e.g., prevention of contrast agent allergy) or treatment of non-autoimmune conditions (e.g., delayed hypersensitivity reactions caused by exposure to allergens); Have received systemic corticosteroids (at a dosage greater than 10 mg/day of prednisone or an equivalent dose of other corticosteroids) within 3 weeks prior to the initiation of study treatment; NOTE: Other protocol defined Inclusion/Exclusion criteria apply
  • Have an uncontrolled intercurrent illness that would limit compliance with study requirement or substantially increase risk of incurring adverse events
  • Have a history of (non-infectious) interstitial lung disease (ILD)/pneumonitis that required steroids, have current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at screening

Where in France

Also in 10 other countries, 80 sites

  • CHU BesançonBesançon, FranceTaking people
  • Centr Georges Francois LeclercDijon, FranceTaking people
  • Clinique Victor HugoLe Mans, FranceTaking people
  • Institut De Cancerologie De L OuestSaint-Herblain Cedex, FranceTaking people
  • Oncopole Claudius RegaudToulouse Cedex 9, FranceTaking people

About the trial

What the trial wants to find out

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 (also known as trastuzumab pamirtecan and DB-1303) in combination with BNT327 (also known as pumitamig and PM8002) 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-negative breast cancer (TNBC).

The 8 groups in the trial

  • Part1 - BNT323 + BNT327 combination therapyTreatment being tested

    Escalating dose levels (DLs) of BNT323 and BNT327 to define RP2D. Six DLs are planned, i.e., DL0-1, DL1-1, DL2-1, DL0-0, DL1-0, DL2-0, a combination of three different DLs for BNT323 (DL0, DL1, and DL2) and two DLs for BNT327 (DL0 and DL1).

    Treatment: BNT323 and BNT327

  • Part 2 Cohort 1 - Arm 1 - RP2D of BNT323 + BNT327Treatment being tested

    Treatment: BNT323 and BNT327

  • Part 2 Cohort 1 - Arm 2 - BNT323 + BNT327Treatment being tested

    Treatment: BNT323 and BNT327

  • Part 2 Cohort 1 - Arm 3 - BNT323 monotherapyTreatment being tested

    BNT323 monotherapy at a fixed dose

    Treatment: BNT323

  • Part 2 Cohort 1 - Arm 4 - BNT327 monotherapyTreatment being tested

    BNT327 monotherapy at a fixed dose

    Treatment: BNT327

  • Part 2 Cohort 2 - RP2D of BNT323 + BNT327Treatment being tested

    Treatment: BNT323 and BNT327

  • Part 2 Cohort 3 - RP2D of BNT323 + BNT327Treatment being tested

    Treatment: BNT323 and BNT327

  • Part 2 Cohort 4 - RP2D of BNT323 + BNT327Treatment being tested

    Treatment: BNT323 and BNT327

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
A Phase I/II, Multi-site, Open-label, Two-part Trial to Evaluate the Efficacy, Safety, and Pharmacokinetics of BNT323 in Combination With BNT327 in Participants With Advanced Breast Cancer
Plain-language title
Tests two investigational drugs together in advanced breast cancerGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 11 November 2026.
Record updated
10 November 2026