# Trastuzumab pamirtecan

Source: https://onco.cc/drugs/trastuzumab-pamirtecan/  
OnCo record `trastuzumab-pamirtecan` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Trastuzumab pamirtecan is DualityBio and BioNTech's HER2 antibody-drug conjugate, in phase 3 trials in breast cancers with high and with modest HER2 expression and in HER2-expressing endometrial cancer.

## Summary

DualityBio's DB-1303, licensed to BioNTech as BNT323, is a HER2-directed antibody-drug conjugate with a topoisomerase I inhibitor payload. Phase 3 trials are testing it in metastatic breast cancer with high and with modest HER2 expression against standard chemotherapy or other HER2 conjugates and in advanced HER2-expressing endometrial cancer, where it received US breakthrough designation. It is one of several conjugates trying to improve on trastuzumab deruxtecan's payload chemistry and tolerability.

## Fields

- Kind: Treatment
- Status: phase-3
- Last checked: 2026-09-16
- Also known as: BNT323
- Tags: pipeline; ctgov-ingest
- Code: DB-1303
- Modality: Antibody-drug conjugate (anti-HER2 antibody, topoisomerase I inhibitor payload)
- Mechanism: A HER2 antibody carrying a topoisomerase I inhibitor payload through a cleavable linker, the same design family as trastuzumab deruxtecan, with a bystander effect on neighbouring cells.

## Sources

- ClinicalTrials.gov: trials of Trastuzumab pamirtecan: https://clinicaltrials.gov/search?intr=DB-1303

## Connected records

- cancers: [Endometrial cancer](https://onco.cc/cancers/endometrial/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/)
- targets: [HER2](https://onco.cc/targets/her2/)
- trials: [A Clinical Study of the Anti-cancer Effects of an Investigational Therapy or Chemotherapy in Patients With Recurring Uterine Cancer](https://onco.cc/trials/nct06340568/), [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](https://onco.cc/trials/nct06827236/), [A Phase 1/2a Study of DB-1303/BNT323 in Advanced/Metastatic Solid Tumors](https://onco.cc/trials/nct05150691/), [A Study of DB-1303/BNT323 vs Investigator's Choice Chemotherapy in HER2-Low, Hormone Receptor Positive Metastatic Breast Cancer (DYNASTY-Bre](https://onco.cc/trials/nct06018337/), [A Study to Compare DB-1303/BNT323 Versus T-DM1 in Breast Cancer](https://onco.cc/trials/nct06265428/)

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