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HER3-DXd

Merck Sharp & Dohme LLC · Phase 2 active Biologic ✓ Verified Jun 2026

HER3-DXd is a HER3-targeting antibody-drug conjugate Biologic drug developed by Merck Sharp & Dohme LLC. It is currently in Phase 2 development for Breast cancer, Gastric cancer. Also known as: patritumab deruxtecan, U3-1402, MK-1022, patritumab deruxtecan, MK-1022, U3-1402.

HER3-DXd is a HER3-targeting antibody-drug conjugate.

HER3-DXd is an antibody used to treat various types of cancer, including gastrointestinal cancer, malignant neoplasm, advanced solid tumor, melanoma, and head and neck cancer. It is a form of patritumab deruxtecan, a treatment being studied in clinical trials.

Likelihood of approval
16.3% vs 15.3% industry baseline
If approved by FDA: likely 2031–2034
Steps remaining: Phase 3 → NDA/BLA submission
Confidence: Medium
Why this estimate
  • Baseline phase 2 → approval rate +15.3pp
    Industry-wide phase 2 drugs reach approval ~15.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
  • Oncology Phase 2 attrition -2.0pp
    Oncology drugs have higher Phase 2-to-Phase 3 attrition than average — many fail to show OS benefit in larger studies.
  • Big-pharma sponsor +3.0pp
    Merck Sharp & Dohme LLC is a top-20 pharma sponsor — historical approval rates run ~3pp above average due to scale, regulatory experience, and trial-design quality.
Predicted approval windows by jurisdiction (conditional on FDA approval)
Regulator Country Likely year Lag vs FDA
FDA US 2031–2034
EMA EU 2032–2035 +0.7 yr
MHRA GB 2032–2035 +0.7 yr
Health Canada CA 2032–2036 +0.9 yr
TGA AU 2032–2036 +1.2 yr
PMDA JP 2032–2036 +1.5 yr
NMPA CN 2033–2037 +2.3 yr
MFDS KR 2032–2036 +1.4 yr
CDSCO IN 2032–2037 +1.8 yr
ANVISA BR 2033–2037 +2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic nameHER3-DXd
Also known aspatritumab deruxtecan, U3-1402, MK-1022, patritumab deruxtecan, MK-1022, U3-1402, Patritumab deruxtecan
SponsorMerck Sharp & Dohme LLC
Drug classHER3-targeting antibody-drug conjugate
TargetHER3
ModalityBiologic
Therapeutic areaOncology
PhasePhase 2

Mechanism of action

HER3-DXd works by binding to the HER3 receptor and delivering a cytotoxic payload to cancer cells that overexpress HER3.

Approved indications

Common side effects

Key clinical trials

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Frequently asked questions about HER3-DXd

What is HER3-DXd?

HER3-DXd is a HER3-targeting antibody-drug conjugate drug developed by Merck Sharp & Dohme LLC, indicated for Breast cancer, Gastric cancer.

How does HER3-DXd work?

HER3-DXd is a HER3-targeting antibody-drug conjugate.

What is HER3-DXd used for?

HER3-DXd is indicated for Breast cancer, Gastric cancer.

Who makes HER3-DXd?

HER3-DXd is developed by Merck Sharp & Dohme LLC (see full Merck Sharp & Dohme LLC pipeline at /company/merck).

Is HER3-DXd also known as anything else?

HER3-DXd is also known as patritumab deruxtecan, U3-1402, MK-1022, patritumab deruxtecan, MK-1022, U3-1402, Patritumab deruxtecan.

What drug class is HER3-DXd in?

HER3-DXd belongs to the HER3-targeting antibody-drug conjugate class. See all HER3-targeting antibody-drug conjugate drugs at /class/her3-targeting-antibody-drug-conjugate.

What development phase is HER3-DXd in?

HER3-DXd is in Phase 2.

What are the side effects of HER3-DXd?

Common side effects of HER3-DXd include Nausea, Fatigue, Diarrhea.

What does HER3-DXd target?

HER3-DXd targets HER3 and is a HER3-targeting antibody-drug conjugate.

Related

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing