An open-label study of lapatinib in women with HER-2-negative early breast cancer: the lapatinib pre-surgical study (LPS study)

Mené sur 31 patientes atteintes d'un cancer du sein HER2-, cet essai de phase II évalue, du point de vue de la mesure de l'inhibition de la prolifération cellulaire à l'aide de Ki67, le lapatinib en traitement pré-opératoire

Résumé en anglais

Background This phase II, open-label, multicentre study aimed to evaluate changes in cell proliferation and biomarkers, as well as efficacy of lapatinib in treatment-naïve patients with HER-2-negative primary breast cancer.

Patients and methods Patients received 1500 mg lapatinib for 28–42 days before surgery with repeat biopsies and measurements. The primary end point was inhibition of cell proliferation measured by Ki67; the secondary end points included clinical response, adverse events and changes in FOXO3a, FOXM1, p-AKT and HER-3.

Results Overall, there was no significant reduction in Ki67 with treatment (assessment carried out in 28 of 31 subjects enrolled). However, four patients (14%) showed a reduction in Ki67 ≥50%. Four of 25 patients (16%) had a partial response to treatment judged by sequential ultrasound measurements. Response, in terms of either Ki67 or ultrasound, did not relate to changes in any biomarker assessed at baseline, including the estrogen receptor (ER) and epidermal growth factor receptor (EGFR). However, all four clinical responders were HER-3 positive, as were three of four Ki67 responders.

Conclusions Overall, a pre-surgical course of lapatinib monotherapy had little effect on this group of patients; however, in subsets of patients, especially those with HER-3-positive tumors, we observed either reduction in proliferation (Ki67) or tumor size; EGFR/ER status had no impact.