Real-World Outcomes of Pyrotinib-Based Therapy for HER2-Positive Breast Cancer With Brain Metastases: A Multicentre, Retrospective Analysis.

OBJECTIVE

This study was designed to investigate the efficacy and safety of pyrotinib-based therapy for HER2-positive breast cancer with brain metastases (BM) in the real-world setting.

METHODS

Data of HER2-positive breast cancer patients with BM treated with pyrotinib-based therapy from a multicetre, registered, real-world study were analyzed.

RESULTS

Among 45 female patients, the overall objective response rate (ORR) was 62.2%, higher in 1st/2nd-line than ≥ 3rd-line (71.0% vs. 42.9%, P = .072). The objective response rate of intracranial lesions (CNS-ORR) was 71.1 %, with a significantly higher CNS-ORR observed in the 1st or 2nd-line subgroup compared to that of ≥ 3rd-line subgroup (83.9% vs. 42.9%, P < .05). By the end of follow-up, 20 patients (44.4%) died, and the 1-year survival rate was 73.3%. The median progression-free survival (PFS) was 9.1 months (95% CI 6.7-11.5). Patients with 1 or 2 BM had a longer median PFS of 12.0 months compared to 7.7 months for those with ≥ 3 BM (P = .01). In addition, 1- or 2-line therapy and full dose exposure of pyrotinib of 320mg-400mg/day were associated with improved median PFS (all P > .05). The median intracranial PFS (CNS-PFS) was 11.4 months (95% CI 7.5-15.3). However, local intervention plus systemic treatment seemed to prolong CNS-PFS compared with systemic treatment alone (13.7 vs. 9.1 months, P = .128). Diarrhea was most common (88.9%), 24.4% grade 3.

CONCLUSIONS

The pyrotinib-based therapy is effective for HER-2 positive breast cancer with BM, especially in 1st- or 2nd-line treatment, with tolerable adverse events. However, insufficient dosing of pyrotinib may impair efficacy outcomes.