# Pyrotinib-assisted whole brain radiotherapy alleviates HER2-positive advanced breast cancer and brain metastases: a prospective study in patients

## TL;DR

This study shows that combining whole-brain radiotherapy with pyrotinib improves survival and response rates in patients with HER2-positive advanced breast cancer and brain metastases.

## Contribution

The study introduces a new treatment protocol combining pyrotinib with whole-brain radiotherapy for HER2+ breast cancer with brain metastases.

## Key findings

- Combining WBRT with pyrotinib achieved median intracranial progression-free survival of 25 months.
- High intracranial objective response and clinical benefit rates were observed without significant differences between treatment sequences.
- Treatment was well-tolerated with mostly grade 1–3 adverse events.

## Abstract

The whole-brain radiotherapy (WRBT)-based therapeutic efficacy is often limited against human epidermal growth factor receptor 2 (HER2+)-positive advanced breast cancer (BC) and brain metastases (BM), requiring more effective treatment options. This prospective study evaluates the effectiveness and safety of combining WBRT with pyrotinib in patients with HER2+ advanced BC and BM.

The enrolled patients (n = 26, from April 2019 to March 2022) were divided into two treatment groups. Group 1 (p-WBRT) received pyrotinib initially, followed by subsequent WBRT. Group 2 (WBRT-p) received WBRT concurrently with pyrotinib. The intracranial progression-free survival (iPFS) was determined.

In the WBRT-p group (n = 11), the median iPFS was recorded as 25.0 months (95% CI, 15.3–34.7), while the overall survival (OS) rates in 1–4 years were 100, 54.5, 9.1, and 0%, respectively. The intracranial objective response rate (iORR) and intracranial clinical benefit rate (iCBR) were 63.6 and 90.9%, respectively. In the p-WBRT group (n = 15), the median iPFS was around 22.0 months (95% CI, 4.3–39.7), and the OS rates in 1–4 years were 100, 53.3, 33.3, and 6.7%, respectively. The iORR and iCBR values were 66.7 and 80.0%, respectively. Notably, no significant differences in iPFS, OS, iORR, and iCBR were observed between treatment groups. Although some instances of adverse events, such as vomiting and reduced white blood cells and neutrophil counts, were evident, these adverse events were grades 1–3.

WBRT combined with pyrotinib exhibited exceptional tolerability, showing long iPFS in patients with HER2+ advanced BC and BM.