PALLAS CLINICAL TRIAL UPDATE

An interim analysis of the global phase 3 clinical trial PALLAS has determined that the addition of palbociclib to standard therapy is unlikely to show a statistically significant improvement in the primary endpoint, invasive disease-free survival, compared with treatments already available to patients with early hormone receptor positive breast cancer.

Palbociclib is a cell cycle inhibitor that has been proven to be effective in the treatment of advanced breast cancer. The primary aim of the PALLAS clinical trial was to determine if the addition of palbociclib to adjuvant hormone therapy could reduce the risk of breast cancer recurrence. The trial was open to both women and men diagnosed with Hormone Receptor (HR) positive, Human Epidermal Growth Factor Receptor 2 (HER2) negative, early stage breast cancer.

The planned interim analysis, reviewed by the Independent Data Monitoring Committee for the PALLAS clinical trial, found that a futility boundary was crossed which indicates a low probability that the study would meet its primary endpoint and lead to a significant improvement. As a result, patients currently in the active phase of the trial will be counselled/instructed by their physicians that they are no longer required to take palbociclib and all patients will move to protocol follow-up. Long-term follow up of patient outcomes will proceed as planned.

The Breast Cancer Trials Study Chair of the PALLAS clinical trial, Dr Nicholas Zdenkowski, says the current treatment remains the best available standard of care for these patients.

“Many patients with HR positive, HER2-negative breast cancer will be cured of their disease with currently available therapies, indicating that adjuvant therapy for early breast cancer can be extremely effective.”

“This trial will continue to produce results which will help researchers to answer questions about treatment and disease patterns in patients with stage II and III breast cancer, who are at greater risk of their breast cancer returning. This trial is collecting extensive information through tumour and blood samples, patient questionnaires, treatments and disease outcomes that will be examined closely.”

“Importantly, the PALLAS trial itself, including clinical and scientific analyses, has not stopped and this event has no impact on current guidelines for use of palbociclib or related CDK4/6 inhibitors for patients with metastatic HR+/HER2- breast cancer.”

The PALLAS clinical trial is led by the Austrian Breast & Colorectal Cancer Group (ABCSG) and is led in Australia by Breast Cancer Trials. 21 countries enrolled a total of 5,796 patients to the trial include 434 patients from Australia.

Media contact: Anna Fitzgerald, BCT Communications Manager 0400 304 224 or anna.fitzgerald@bctrials.org.au

Our life-saving breast cancer research is only possible thanks to the continued generosity of our supporters. Please help continue this vital work by making a donation today.