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BNT323

Phase 1

Locally Advanced Breast Cancer | Small molecule | Oncology |BioNTech SE|Last Updated: Aug 27, 2026

Target and mechanism

Molecular targetHER2
Target classProtein
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLED
Total Trials1
Total Enrollment380

FDA Designations

BREAKTHROUGH_THERAPYFAST_TRACK

Clinical trial landscape

BNT323 · 1 trial · 3 indications

Phase 1 1
NCT06827236A 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 CancerLocally Advanced Breast Cancer
RECRUITING380 Analytics
PHASE1RECRUITING
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
Locally Advanced Breast CancerUnlock trial analytics

Study Endpoints

Primary Endpoints

Part 1 - Occurrence of dose limiting toxicities (DLTs)
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
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
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)
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.

Secondary Endpoints

Part 1 - ORR
From the time of initiation of the first dose of IMP to last tumor assessment scan, i.e., up to 36 months.
Part 2 - Duration of response (DoR)
From the time of initiation of the first dose of IMP to last tumor assessment scan, i.e., up to 36 months.
Part 2 - Disease control rate (DCR)
From the time of initiation of the first dose of IMP to last tumor assessment scan, i.e., up to 36 months.
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Part1 - BNT323 + BNT327 combination therapyEXPERIMENTALEscalating 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).
Part 2 Cohort 1 - Arm 1 - RP2D of BNT323 + BNT327EXPERIMENTAL -
Part 2 Cohort 1 - Arm 2 - BNT323 + BNT327EXPERIMENTAL -
Part 2 Cohort 1 - Arm 3 - BNT323 monotherapyEXPERIMENTALBNT323 monotherapy at a fixed dose
Part 2 Cohort 1 - Arm 4 - BNT327 monotherapyEXPERIMENTALBNT327 monotherapy at a fixed dose
Part 2 Cohort 2 - RP2D of BNT323 + BNT327EXPERIMENTAL -
Part 2 Cohort 3 - RP2D of BNT323 + BNT327EXPERIMENTAL -
Part 2 Cohort 4 - RP2D of BNT323 + BNT327EXPERIMENTAL -

Interventions

NameTypeDescription
BNT323DRUGIntravenous infusion
BNT327DRUGIntravenous infusion
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites78

Key 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 as standard of care testing prior t...

Countries:United StatesAustraliaCanadaChinaFranceGeorgiaItalyMoldovaSpainTurkey (Türkiye)United Kingdom
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Recent Changes (Last 90 Days)

LOWAug 27, 2026NCT06827236lastUpdatePostDate: changed
LOWAug 27, 2026NCT06827236lastUpdatePostDate: changed
LOWJul 21, 2026NCT06827236lastUpdatePostDate: changed
MEDIUMJun 23, 2026NCT06827236primaryCompletionDate: changed
MEDIUMJun 23, 2026NCT06827236primaryCompletionDate: changed

Frequently asked questions about BNT323

What is BNT323 used for?

BNT323 is an investigational oncology therapy being studied for endometrial cancer and locally advanced breast cancer. It is also known as BNT323/DB-1303 and is being developed by BioNTech SE (BNTX). The drug is currently in clinical development and has not been approved by the FDA.

What does BNT323 target?

BNT323 targets HER2, a protein found on the surface of some cancer cells. By targeting HER2, the drug is designed to interfere with cancer cell growth and survival. This mechanism is being evaluated in clinical trials for HER2-expressing cancers, including endometrial and breast cancers.

Who makes BNT323?

BNT323 is being developed by BioNTech SE, a biotechnology company traded on the Nasdaq under the ticker BNTX. BioNTech is conducting clinical trials to evaluate the safety and efficacy of BNT323 in patients with certain types of cancer.

What phase is BNT323 in?

BNT323 is in Phase 1 clinical development, with an active Phase 1 trial recruiting patients. The drug has received Breakthrough Therapy and Fast Track designations from the FDA, reflecting its potential to address serious conditions. It remains investigational and is not yet approved.

What clinical trials is BNT323 in?

BNT323 is being studied in two clinical trials. NCT06340568 is a Phase 3 trial in endometrial cancer with 480 participants, and NCT06827236 is a Phase 1 trial in advanced breast cancer with 380 participants. Both trials are currently recruiting patients.

Is BNT323 the same as BNT323/DB-1303?

Yes, BNT323 is also known as BNT323/DB-1303. The drug is referred to by this alternative name in some clinical and research contexts. Both names refer to the same investigational therapy being developed by BioNTech SE.