# HER2CLIMB-02

Source: https://onco.cc/trials/her2climb-02/  
OnCo record `her2climb-02` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Adding tucatinib to Kadcyla helped a little, mostly in patients with brain metastases, but did not extend survival.

## Summary

HER2CLIMB-02, trial NCT03975647 sponsored by Seagen, now Pfizer, and reported in 2023, tested adding tucatinib to trastuzumab emtansine in HER2-positive metastatic breast cancer after trastuzumab and a taxane, and found a small progression-free survival benefit, mostly in patients with brain metastases, without an improvement in overall survival. It randomised 463 women and met its primary progression-free survival endpoint with a modest effect, larger in the brain metastasis subgroup, but the combination has been superseded by trastuzumab deruxtecan in the second line and by HER2CLIMB-05 in maintenance. OnCo links it to tucatinib and trastuzumab emtansine, and the result is consistent with the central nervous system signal seen in HER2CLIMB. Whether tucatinib adds anything to newer antibody-drug conjugates for brain metastases is the open question. Tucatinib has its own page.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-07
- Registry id: NCT03975647
- Phase: 3
- Setting: HER2+ metastatic breast cancer after trastuzumab and taxane: tucatinib + T-DM1 vs placebo + T-DM1
- Sponsor: Seagen (Pfizer)
- Enrolled: 466
- Result: PFS 9.5 vs 7.4 months, HR 0.76; OS no benefit.
- Outcomes: Progression-free survival: Tucatinib + T-DM1 9.5 months vs Placebo + T-DM1 7.4 months, HR 0.76
- Replication: Consistent with HER2CLIMB's CNS signal.

## Sources

- ClinicalTrials.gov NCT03975647: https://clinicaltrials.gov/study/NCT03975647

## Connected records

- cancers: [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [HER2-positive breast cancer with brain metastases](https://onco.cc/cancers/her2-positive-breast-brain-metastases/)
- technologies: [HER2 tyrosine kinase inhibitors](https://onco.cc/technologies/her2-tyrosine-kinase-inhibitors/), [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- drugs: [Trastuzumab emtansine](https://onco.cc/drugs/trastuzumab-emtansine/), [Tucatinib](https://onco.cc/drugs/tucatinib/)
- companies: [Pfizer (incl. Seagen)](https://onco.cc/companies/pfizer/)
- key papers: [Tucatinib and trastuzumab emtansine for patients with previously treated HER2-positive locally advanced and metastatic breast cancer: primary analysis of the randomized phase III trial HER2CLIMB-02](https://onco.cc/key-papers/paper-her2climb-02-ann-oncol-2026/)

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