Last reviewed 2026-04-23 · How we verify

HER3-DXd

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

HER3-DXd is a HER3-targeting antibody-drug conjugate. Used for Breast cancer, Gastric cancer.

At a glance

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

• Breast cancer
• Gastric cancer

Common side effects

• Nausea
• Fatigue
• Diarrhea

Key clinical trials

• A Study of Patritumab Deruxtecan in Pediatric Participants With Relapsed or Refractory Solid Tumors (MK-9999-01C/LIGHTBEAM-U01) (PHASE1, PHASE2)
• A Clinical Study of Patritumab Deruxtecan to Treat Breast Cancer (MK-1022-016) (PHASE3)
• Substudy 06C: A Study of Investigational Agents With Pembrolizumab (MK-3475) and Chemotherapy in Participants With First-Line Locally Advanced Unresectable/Metastatic Gastroesophageal Adenocarcinoma (MK-3475-06C/KEYMAKER-U06) (PHASE1, PHASE2)
• Substudy 06D: Combination Therapies in Second Line (2L) Gastroesophageal Adenocarcinoma (MK-3475-06D/Keymaker-U06) (PHASE1, PHASE2)
• KEYMAKER-U01 Substudy 01A: Efficacy and Safety Study of Pembrolizumab (MK-3475) With or Without Chemotherapy When Used With Investigational Agents in Treatment-naïve Participants With Stage IV Non-small Cell Lung Cancer (NSCLC) (MK-3475-01A/KEYMAKER-U01A) (PHASE1, PHASE2)
• A Clinical Study of MK-1084 With Other Treatments for Non-small Cell Lung Cancer (MK-3475-01F) (PHASE1, PHASE2)
• Study of Patritumab Deruxtecan in Participants With Gastrointestinal Cancers (MK-1022-011) (HERTHENA-PanTumor02) (PHASE1, PHASE2)
• Study of Patritumab Deruxtecan Plus Pembrolizumab With Other Anticancer Agents in Participants With High-Risk Early-Stage Triple-Negative or Hormone Receptor-Low Positive/HER-2 Negative Breast Cancer (MK-1022-010, HERTHENA-Breast-03) (PHASE2)

Primary sources

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