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A New Year, A New Class of Drugs Approved to Treat Breast Cancer

By BCRF | January 17, 2018

FDA approves the first PARP inhibitor for the treatment of HER2-negative metastatic breast cancer in patients with BRCA mutations.

A new type of drug is now approved for certain patients with metastatic breast cancer. Olaparib (Lynparza®) belongs to a class of drugs called PARP inhibitors. It was the first PARP inhibitor approved for ovarian cancer in patients with BRCA mutations and is now approved for use in advanced breast cancer. Other recent breast cancer drug approvals include ribociclib and abemaciclib, which join palbociclib in the CDK4/6 family, while olaparib creates a whole new category.

PARP is an enzyme involved in DNA repair. Cells that have defects in DNA repair processes rely heavily on PARP to stay alive and grow. Blocking PARP has been shown to be especially potent in cancer cells with DNA repair deficiency, such as those with BRCA mutations.

What does this mean for patients?

“The approval of olaparib allows for better options for individuals with BRCA1/2 associated metastatic breast cancer. Importantly, olaparib is also the first FDA approved targeted therapy for a subset of triple negative breast cancer,” BCRF researcher Dr. Susan Domchek said commenting on the clinical implications of this development. 

Following reports from the OlympiAD trial reported in the New England Journal of Medicine, led by BCRF investigator Mark Robson along with BCRF investigators Susan Domchek and Nadine Tung and colleagues, the FDA approved olaparib, an oral medication, for HER2-negative metastatic breast cancer in patients with inherited BRCA1 or BRCA2 mutations.

For both ER-positive and HER2-positive breast cancers, several options for targeted therapies exist which have greatly improved the outcomes for patients with these types of breast cancer. In addition to being the first PARP inhibitor in breast cancer, olaparib brings a new targeted therapy to BRCA1- and BRCA2-associated HER2-negative breast cancers.

BRCA mutations significantly increase the risk of breast and ovarian cancer in women and breast and prostate cancer in men. Women who carry a BRCA mutation are more likely to be diagnosed with breast cancer before the age of 40 and more likely to have triple negative breast cancer, an aggressive form of the disease for which there are few treatment options.

The action by the FDA to expand the use of olaparib for HER2-negative metastatic breast cancer creates new treatment option for women with an inherited BRCA mutation.

 “This is an exciting time in breast cancer research.” Dr. Judy Garber, Chair of BCRF Scientific Advisory Board noted. “In 2015, the FDA approved an entirely new class of drugs called CDK4/6 inhibitors added to the arsenal for patients with ER-positive metastatic breast cancer. Physicians now have three approved CDK4/6 drugs, palbociclib (Ibrance®), ribociclib (Kisqali®), and abemaciclib (Verzenio®). The expanded approval of olaparib (Lynparza®) is the first of an exciting advancement for a new group of patients with metastatic disease.”

Bringing a new drug that exploits a new mechanism in breast cancer takes a huge and multifaceted effort.  BCRF investigators have contributed across the spectrum from the most basic scientific understanding of DNA repair, how it might be compromised in breast and other cancers and how those deficiencies might be exploited in individuals with BRCA mutations, to the clinical research in designing and implementing the critical clinical trials.  Below is a list of BCRF investigators whose work has contributed to the development of PARP inhibitors in breast or ovarian cancer.  Some also contributed to the approval of PARP inhibitors in ovarian cancer:

Alan Ashworth, PhD, University of California, San Francisco

Lewis Cantley, PhD Weill Cornell Medical College

Alan d’Andrea, MD, Dana Farber Cancer Institute

Angela DeMichele, MD University of Pennsylvania

Susan Domchek, MD, University of Pennsylvania

Laura Esserman, MD, University of California, San Francisco

James Ford, MD, Stanford University

Shridar Ganesan, MD, PhD, Rutgers University Cancer Institute of New Jersey

Judy Garber, MD, Dana Farber Cancer Institute

Maria Jasin, PhD, Memorial Sloan Kettering Cancer Center

Mary-Claire King, PhD, University of Washington

Ephrat Levy-Lahad, MD

David Livingston, MD, Dana Farber Cancer Institute

Joan Marks, Sarah Lawrence College

Ursula Matulonis, MD, Dana Farber Cancer Institute

Kenneth Offit, MD, Memorial Sloan Kettering Cancer Center

Mark Robson, MD Memorial Sloan Kettering Cancer Center

Hope Rugo, MD, University of California, San Francisco

Nadine Tung, MD, Beth Israel Deaconess Medical Center

Jeffrey Weitzel, MD, City of Hope

Eric Winer, MD, Dana Farber Cancer Institute

Gerburg Wolf, PhD, Beth Israel Deaconess Medical Center

Read more about their BCRF research on the BCRF Researchers page

For more about the CDK4/6 inhibitors, check out these progress report blogs