# BOLERO-2

Source: https://onco.cc/trials/bolero-2/  
OnCo record `bolero-2` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

BOLERO-2 showed that adding the mTOR inhibitor everolimus to the hormone drug exemestane more than doubled the time that advanced breast cancer stayed under control after aromatase inhibitors had stopped working, the first targeted drug to overcome endocrine resistance.

## Summary

BOLERO-2 randomised 724 postmenopausal women with hormone receptor-positive, HER2-negative advanced breast cancer that had recurred or progressed on letrozole or anastrozole two to one to exemestane plus everolimus or exemestane plus placebo. The primary endpoint was progression-free survival.

Everolimus more than doubled median progression-free survival, at the cost of stomatitis, rash, fatigue, hyperglycaemia and pneumonitis, and overall survival was not significantly different. It was approved in the United States in July 2012 and was the standard second-line option until CDK4/6 inhibitors arrived; it remains an option after CDK4/6 inhibitor progression, particularly in tumours without a PIK3CA mutation.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-17
- Tags: subtype-trials
- Registry id: NCT00863655
- Phase: 3
- Setting: Postmenopausal hormone receptor-positive, HER2-negative advanced breast cancer after a non-steroidal aromatase inhibitor: exemestane with everolimus or placebo
- Sponsor: Novartis
- Enrolled: 724
- Result: Everolimus plus exemestane more than doubled progression-free survival compared with exemestane alone; approved in July 2012.

## Sources

- ClinicalTrials.gov NCT00863655: https://clinicaltrials.gov/study/NCT00863655

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [HR-positive metastatic breast cancer after CDK4/6 inhibitors](https://onco.cc/cancers/hr-positive-metastatic-post-cdk46/)
- drugs: [Everolimus](https://onco.cc/drugs/everolimus/), [Exemestane](https://onco.cc/drugs/exemestane/)
- companies: [Novartis](https://onco.cc/companies/novartis/)
- people: [José Baselga](https://onco.cc/people/jose-baselga/)

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JSON: https://onco.cc/api/v1/entities/bolero-2.json