Development of acneiform rash does not predict response to lapatinib treatment in patients with breast cancer

To determine if development of acneiform rash is a predictor of objective response rate with lapatinib.

Subanalysis of data from a prospective, phase II study.

Academic breast care clinic.

Forty-nine treatment-naïve patients with human epidermal growth factor receptor-2 (HER2)-positive locally advanced breast cancer, who were treated with neoadjuvant lapatinib monotherapy for 6 weeks; 47 patients were included in the final analysis.

Of the 49 patients enrolled, 33 (67%) developed a rash of any type, and 26 (55%) had acneiform rash. Of the 26 evaluable patients with acneiform rash (55%), 19 (73%) responded to lapatinib and 7 (27%) did not. Of the 21 evaluable patients without acneiform rash, 11 (67%) responded to treatment and 7 (33%) did not. Thus, no association was found between the occurrence of acneiform rash and response to lapatinib monotherapy.

This study does not support the development of the acneiform rash as a predictor of clinical efficacy of lapatinib in the treatment of breast cancer.