# ATEMPT

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

## TL;DR

ATEMPT tested whether a year of the antibody-drug conjugate T-DM1 could replace chemotherapy plus trastuzumab for the smallest HER2-positive breast cancers; almost no one relapsed on T-DM1, but it was not less toxic overall, so it is an alternative rather than a replacement.

## Summary

The APT trial had shown that paclitaxel plus trastuzumab cures almost all node-negative HER2-positive tumours of 3 cm or less. ATEMPT randomised 497 patients with stage I HER2-positive breast cancer three to one to 17 cycles of trastuzumab emtansine or to the APT regimen. The co-primary endpoints were invasive disease-free survival with T-DM1 and a comparison of clinically relevant toxicities.

Three-year invasive disease-free survival with T-DM1 was very high, but the rate of clinically relevant toxicity was similar in the two arms, so the toxicity endpoint was not met; T-DM1 caused more thrombocytopenia and liver enzyme rises, paclitaxel more neuropathy and alopecia. T-DM1 is now listed as an alternative adjuvant option for stage I disease, especially for patients who wish to avoid chemotherapy side effects.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-17
- Tags: subtype-trials
- Registry id: NCT01853748
- Phase: 2
- Setting: Stage I HER2-positive breast cancer: one year of trastuzumab emtansine against paclitaxel plus trastuzumab (the APT regimen)
- Sponsor: Dana-Farber Cancer Institute
- Enrolled: 512
- Result: Very high three-year invasive disease-free survival with one year of trastuzumab emtansine in stage I disease, but clinically relevant toxicity was not lower than with paclitaxel plus trastuzumab.

## Sources

- ClinicalTrials.gov NCT01853748: https://clinicaltrials.gov/study/NCT01853748

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Early HER2-positive breast cancer](https://onco.cc/cancers/her2-positive-early-breast-cancer/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/)
- drugs: [Paclitaxel / nab-paclitaxel](https://onco.cc/drugs/paclitaxel/), [Trastuzumab](https://onco.cc/drugs/trastuzumab/), [Trastuzumab emtansine](https://onco.cc/drugs/trastuzumab-emtansine/)
- companies: [Roche / Genentech](https://onco.cc/companies/roche-genentech/)
- people: [Sara M. Tolaney](https://onco.cc/people/sara-tolaney/)

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JSON: https://onco.cc/api/v1/entities/atempt.json