HER3 is a cousin of HER2 that cancers use as an escape route when HER2 or EGFR are blocked. This dossier gathers the 4 products (2 approved), 8 trials, 0 pathways and 1 resistance route in the corpus that involve it, with external identifiers so it can be joined to UniProt, ChEMBL, Open Targets and the rest of biology.
Biology
Neuregulin (NRG1) ligand; NRG1 fusions are rare drivers targeted by zenocutuzumab. Broadly expressed across breast, lung, and colorectal cancers.
- Breast cancer (all subtypes)
- EGFR-mutant NSCLC
- Colorectal
- NRG1-fusion tumours
Elsewhere: identifiers and databases
Built from HGNC, Ensembl, UniProt and ChEMBL idsHow common it is, by cancer
Full matrix →| Cancer | Prevalence | Measure | Note | Source |
|---|---|---|---|---|
| Non-small-cell lung cancer | 80-90% | IHC, any expression | EGFR-mutant NSCLC in HERTHENA-Lung01 | Wikipedia |
| Triple-negative breast cancer | 50-70% | IHC, any expression | Wikipedia | |
| HR-positive / HER2-negative breast cancer | 50-70% | IHC, any expression | Wikipedia |
Approximate, population-level figures; the measure column says what was counted. Ranges show the midpoint as a bar.
Products by modality and phase
Browse products →| Modality | Approved | Phase 3 |
|---|---|---|
| ADC 1 | — | |
| Antibody 1 | — | |
| Bispecific ADC 1 | — | |
| Bispecific antibody 1 | — |
Trials
Evidence ranking →| Trial | Phase | Status | Setting | Result | Products |
|---|---|---|---|---|---|
| BL-B01D1-307 NCT06382142 | 3 | Positive | Previously treated locally advanced or metastatic TNBC: izalontamab brengitecan vs chemotherapy | PFS and OS significantly improved at interim analysis (numbers presented ASCO 2026). | |
| PANKU-Esophagus01 (BL-B01D1-305) NCT06304974 | 3 | Positive | Recurrent or metastatic oesophageal squamous cell carcinoma after PD-(L)1 inhibitor plus platinum chemotherapy: izalontamab brengitecan vs chemotherapy of physician's choice | OS and PFS significantly improved at interim analysis; numbers per ASCO 2026 presentation. | |
| HER2CLIMB-05 NCT05132582 | 3 | Positive | First-line HER2+ metastatic breast cancer after induction with taxane + trastuzumab + pertuzumab: maintenance tucatinib + HP vs placebo + HP | PFS 24.9 vs 16.3 months, HR 0.64. | |
| HERTHENA-Lung02 NCT05338970 | 3 | Mixed | EGFR-mutant NSCLC after third-generation TKI: patritumab deruxtecan vs platinum chemotherapy | PFS HR 0.77 (5.8 vs 5.4 months); OS not significant; BLA withdrawn. | |
| APHINITY NCT01358877 | 3 | Positive | Adjuvant HER2+ early breast cancer: pertuzumab + trastuzumab + chemotherapy vs placebo + trastuzumab + chemotherapy | 8-year iDFS HR 0.78; node-positive absolute +4.9%. | |
| CLEOPATRA NCT00567190 | 3 | Positive | First-line HER2+ metastatic breast cancer: pertuzumab + trastuzumab + docetaxel vs placebo + trastuzumab + docetaxel | OS 57.1 vs 40.8 months, HR 0.69. | |
| IZABRIGHT-Breast01 NCT06926868 | 3 | Recruiting | First-line metastatic TNBC ineligible for PD-(L)1 inhibitors: iza-bren vs chemotherapy | ||
| PHERGain NCT03161353 | 2 | Positive | HER2+ early breast cancer: chemotherapy-free trastuzumab + pertuzumab with early 18F-FDG PET response assessment to decide whether chemotherapy is needed | 3-year iDFS 95.4% in the PET-adapted arm; ~1 in 3 spared chemotherapy. |
Resistance routes that involve this target
Unaddressed routes →Mutation of the cysteine that osimertinib binds covalently; abolishes drug binding while EGFR stays active.
- Fourth-generation allosteric EGFR inhibitors (in trials); amivantamab-based regimens
- ADCs that bypass genotype: Dato-DXd, HER3-DXd, iza-bren
Pathways where it is a node
Pathway-to-drug matrix →No pathway diagram carries this target as a node.
Companion diagnostics and assays
Assay registry →No companion diagnostic in the registry measures this target.
Preclinical models
All models →No model entry for this target yet; check the cancer entries on the models page.
Open questions
All open questions →No open questions recorded for this target yet. Suggest one.
Ideas and companies
Key papers and the live literature
Preprints →Query for this target: (TITLE:"HER3" OR ABSTRACT:"HER3" OR TITLE:"ERBB3" OR ABSTRACT:"ERBB3") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about HER3, not a curated reading list.
Export
The dossier as machine-readable JSON: identifiers from HGNC, Ensembl, UniProt and ChEMBL, products with status, trials, pathways, hotspots, open questions and assays. The full entity record is in the open API at /api/v1/entities/her3.json. Licence CC BY 4.0.