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Patritumab Deruxtecan · MK-1022, U31402

Antibody-drug conjugate · Cytotoxic, directed at HER3 (ERBB3) · developed by Merck &

Phase 3 Most advanced trial

MRK Developer

1 Registered trials

What is Patritumab Deruxtecan?

Patritumab deruxtecan is an antibody-drug conjugate composed of patritumab, a monoclonal antibody targeting HER3, linked to DX 8951, a topoisomerase I inhibitor. Upon binding to HER3 and internalization, DX 8951 stabilizes the topoisomerase I-DNA complex, inhibiting DNA replication and triggering apoptosis. It is studied in breast cancer.

Summary written with AI from the sources listed at the end of this page.

At a glance

Also known as: MK-1022, U31402, HER3-DXd, U3-1402
Drug type: Antibody-drug conjugate
Targets: HER3 (ERBB3), topoisomerase I (TOP1) (secondary target)
Mechanism: Cytotoxic, directed at HER3 (ERBB3)
Pathways: DNA replication inhibition, apoptosis
Therapy area: Oncology
Developer: Merck & Co. (MRK)
FDA status: Investigational, not approved in the US. Most advanced trial: Phase 3
UNII: 3XPI7EG4W8

🧪 Clinical trials

Trial	Phase	Condition	Status	Sponsor
NCT07060807	Phase 3	Breast Neoplasms	Recruiting	MRK

Trials of the companies BioRadar tracks, from ClinicalTrials.gov, most advanced phase first.

Conditions studied

Breast Neoplasms

Other drugs acting on ERBB3

CDX-3379 Phase 2 Izalontamab Brengitecan Phase 2/3

More from Merck &

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Sources

Updated Oct 3, 2026. Something wrong or missing? Report it on the MRK page.

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Data: FDA (Drugs@FDA, Purple Book, DailyMed), NIH (NCI Thesaurus, GSRS, RxNorm), ClinicalTrials.gov • Informational purposes only, not medical or investment advice. • All drugs A–Z