# Enhertu by Daiichi Sankyo

Canonical page: https://technooptimist.io/biotech/enhertu
Frontier: [Biotech](https://technooptimist.io/biotech.md) · Field: Antibody drugs · Company: [Daiichi Sankyo](https://technooptimist.io/companies/daiichi-sankyo.md)
Stage: Scaling (5 of 5: Research → Proto → Pilot → Deploy → Scaling)
Updated: last update 2026-05-15, facts checked 2026-10-11
Goal: Deliver chemotherapy straight into HER2-bearing cancer cells so far more drug reaches the tumour and less the rest of the body, and move that benefit from late-stage disease to the first treatment patients get.
Status: Approved in 5 cancer types; added first-line HER2+ (Dec 2025) and early breast cancer (May 2026).

## Milestones

| Status | Milestone | Date | Slip |
| --- | --- | --- | --- |
| Done | AstraZeneca partnership signed | Mar 2019 |   |
| Done | FDA: first drug for HER2-low breast cancer (DESTINY-Breast04) | 5 Aug 2022 |   |
| Done | FDA: first-line HER2+ metastatic, with pertuzumab (DESTINY-Breast09) | Dec 2025 |   |
| Done | FDA: early HER2+ breast cancer before and after surgery | 15 May 2026 |   |

## Most important updates

- **15 May 2026**: FDA approves Enhertu for early HER2-positive breast cancer, both before and after surgery. Enhertu moved into curative-intent treatment with two US approvals for early HER2-positive breast cancer. ([our story](https://technooptimist.io/stories/fda-approves-enhertu-for-early-her2-positive-breast-cancer-both-before-21ce340f.md) · [original source](https://www.curetoday.com/view/fda-approves-enhertu-for-her2-positive-early-stage-breast-cancer))
- **10 Dec 2025**: Enhertu plus pertuzumab approved in the US as first-line treatment for HER2-positive metastatic breast cancer. The FDA approved Enhertu with pertuzumab as the first treatment for HER2-positive metastatic breast cancer, the first new first-line option in more than a decade. ([our story](https://technooptimist.io/stories/enhertu-plus-pertuzumab-approved-in-the-us-as-first-line-treatment-for-b68a6253.md) · [original source](https://www.biospace.com/press-releases/enhertu-plus-pertuzumab-approved-in-the-u-s-as-first-new-treatment-in-more-than-a-decade-for-first-line-treatment-of-patients-with-her2-positive-metastatic-breast-cancer))
- **5 Aug 2022**: FDA approves Enhertu as the first treatment for HER2-low breast cancer. The FDA approved Enhertu for metastatic breast cancer with low HER2 levels, a group that had been treated as HER2-negative and had no targeted option. ([our story](https://technooptimist.io/stories/fda-approves-enhertu-as-the-first-treatment-for-her2-low-breast-cancer-18b553b7.md) · [original source](https://www.onclive.com/view/fda-approves-trastuzumab-deruxtecan-for-unresectable-or-metastatic-her2-low-breast-cancer))

## Current obstacles

- **Interstitial lung disease**: Boxed warning: lung inflammation, sometimes fatal; adjuvant use saw 9.6% vs 1.6% on T-DM1. Needs scans and quick steroids.
- **Resistance after progression**: Tumours that progress on Enhertu can lose HER2 or resist topoisomerase poisons, limiting what can follow it.

## Physics limits

- **Only a sliver of the drug reaches the tumour**: Antibodies are large and penetrate solid tumours slowly; most of an infused dose is cleared elsewhere, so payload toxicity in healthy tissue sets the dose ceiling.
- **Healthy tissue takes up poison too**: Any healthy cell that carries the target or swallows the conjugate also receives the payload; lung inflammation, the main dose-limiting harm, is one result.

## How it works

### Antibody: Trastuzumab finds HER2

The antibody docks on HER2, a growth receptor that some breast, stomach and lung cancers carry in large amounts.

### Linker: Cut only inside the cell

A four-amino-acid linker stays intact in blood and is cleaved by enzymes once the conjugate is swallowed by the cell.

### Payload: DXd breaks DNA copying

The released exatecan derivative jams topoisomerase I, so the cancer cell's DNA snaps when it tries to divide.

### Spill-over: Reaches HER2-low cells

Payload leaking to neighbours explains why it works even when only some cells carry a little HER2.

## Spec sheet

| Spec | Enhertu | Provenance |
| --- | --- | --- |
| 1st-line PFS (DB-09) vs standard | 40.7 vs 26.9 months (HR 0.56) | reported |
| 3-yr disease-free after surgery (DB-05) | 92.4% vs 83.7% on T-DM1 | reported |
| Tumour gone at surgery (DB-11) | 67.3% vs 56.3% | reported |
| HER2-low survival (DB-04) | 23.4 vs 16.8 months (HR 0.64) | reported |
| Countries approved (HER2+ breast) | 90+ | reported |
| Lung inflammation (with pertuzumab) | 12% (0.5% fatal) | reported |
| Dose | 5.4 mg/kg every 3 weeks | reported |

Provenance: reported = stated by the company; estimated = our estimate; sample = a sample figure.

## About Daiichi Sankyo

Japanese drugmaker whose DXd technology produced the most successful antibody-drug conjugates: Enhertu (HER2) and Datroway (TROP2), both co-developed and sold with AstraZeneca.

- Enhertu is approved in 90+ countries for HER2-positive breast cancer and now used from early disease to first-line metastatic.
- Datroway won a survival benefit in first-line triple-negative breast cancer; US approval May 2026.
- AstraZeneca partnerships: Enhertu since March 2019, Datroway since July 2020; Daiichi keeps Japan and makes the drugs.

- Headquarters: JP
- Status: public
- Website: https://www.daiichisankyo.com
- Partners, customers, investors: AstraZeneca (partner)

Company page: https://technooptimist.io/companies/daiichi-sankyo.md

## Related programs

More from Daiichi Sankyo:

- [Datroway](https://technooptimist.io/biotech/datroway.md) (Deploy)

Everything in Biotech: https://technooptimist.io/biotech.md

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