Study of Panobinostat Monotherapy in Women With HER2-negative Locally Recurrent or Metastatic Breast Cancer

This was a phase II, open label, multi-centre, two-arm, two-stage design, international study of oral panobinostat in women with HER2-negative locally recurrent or metastatic breast cancer. In the first stage of the trial, 21 evaluable patients HR+ (ER+ and/or PgR+), HER2-negative, were to be treated (Arm I); if less than 3 responses were observed, that arm would be stopped and the treatment in this patient population would be declared as ineffective. In the other arm, 27 evaluable patients HR- (ER- and PgR-), HER2-negative, were to be treated (Arm II); if less than 2 responses were observed, that arm would be stopped and the treatment in this patient population would be declared as ineffective. Given these protocol conditions, the study was stopped in Arm II due to low recruitment as there was insufficient data available to draw conclusions regarding efficacy in that arm. It should also be noted that only one response was observed in this group.. In Arm I, among the 25 evaluable patients, the study did not achieve the required number of tumor responses to allow enrolment to continue. As such the protocol was amended to stop enrolment and remove analysis of the initially planned secondary objectives (Progression Free Survival and Overall Survival) considering the small study sample size. The patients already included were given the option to continue in the study until they reached their planned end-of-study visit.