Finding New Treatments for Breast Cancer with Brain Metastases

As if Breast Cancer or Brain Cancer alone were not enough to combat — patients with both now?have new hope in light of fledgling research that is showing progress.

Once breast cancer metastasizes into other areas of the body, particularly the brain, it becomes much more dangerous. And while the National Cancer Institute spends more than $500 million dollars per year on breast cancer research, only two to five percent of this funding goes to study how the disease spreads.

A clinical trial is open nationwide through the Academic Breast Cancer Consortium (ABRCC), giving access to an exciting novel drug therapy combination. The tucatinib, palbocilib and letrozole trial is coordinated by ABRCC and currently open for enrollment at the University of Colorado Cancer Center; University of Texas Health and Science Center in San Antonio, TX; Stony Brook University, NY; University of Arizona, Tucson, AZ; and University of New Mexico, Albuquerque, NM and will also be accruing patients at Northwestern University, Chicago, IL.

There are three well-established predictive markers of breast cancer. They are estrogen receptors (ER), progesterone receptors (PR), and the growth factor receptor HER2, these receptors may be blocked with targeted drugs to stop cancer growth. Breast cancers lacking these three markers are referred to as ?triple-negative? but clinicians and scientists are quickly learning more about cancers that have all three receptors, which are often called ?triple-positive.? There are treatments against each target individually, but when multiple drivers are present, as in ?triple-positive? breast cancer, blocking one often results in cancer nimbly switching to driving its growth with the other two.

The study combines tucatinib, which inhibits HER2, with letrozole targeting ER and PR hormone receptors, and the drug palbociclib, which targets CDK proteins that help cancer cells rush through the process of replication. The three had not been tried together until Elena Shagisultanova, MD, PhD, a breast cancer specialist at UCH, hypothesized there could be a way to target all three drivers at the same time with better results than targeting combinations of any two.

?When metastatic cancer spreads to the brain, it can be especially challenging,? says Dr Peter Kabos, the National Medical Director of the Academic Breast Cancer Consortium (ABRCC) and the Kabos Research Lab for Breast Cancer at UC Denver. ?Many medications aren?t effective in the brain, but exciting early clinical trial data for tucatinib shows that it may be one of the drugs that can penetrate the blood-brain barrier to combat brain metastases.

The trial is funded by the Pfizer ASPIRE Award in Breast Cancer Research. Cascadian Therapeutics and Pfizer are providing the study drugs tucatinib and palbociclib. For more information about trial eligibility and participation, contact brad.mackay@ucdenver.edu or emily.berens@ucdenver.edu

Article excerpted with permission from the University of Colorado Cancer Center blog — for the complete story, click here.

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