Olaparib Beneficial for BRCA-Mutated HER2-Negative Breast Cancer

This transcript has been edited for clarity.

Hi, everyone. It's Dr Kathy Miller from Indiana University. I hope you had a good time tuning in to the American Society of Clinical Oncology (ASCO) meeting.

I want to make sure you saw the biggest news in the breast cancer world that will definitely impact how we treat patients.

We've seen the power of PARP inhibitors in patients with germline BRCA mutations who have metastatic disease. And last weekend at ASCO we saw the results of the first adjuvant trial.

In this trial, patients with germline BRCA mutations who had stage II or III, HER2-negative disease were enrolled. This was an add-on design. Patients had completed all of their other standard therapy, other than perhaps ongoing hormone therapy for those who were ER positive. They were randomized to olaparib or no olaparib.

The results are striking.

There was a 42% reduction in the risk for recurrence; in absolute terms, almost a 9% reduction in the risk for recurrence. The therapy comes in pill form. For the majority of patients, it's generally well tolerated. There is some myelosuppression, particularly anemia. Some patients do need some dose modifications. In terms of day-to-day toxicity that impacts patient functioning, it is very different from thinking about additional chemotherapy for a really dramatic improvement in outcome.

We do not yet have FDA approval. You can certainly bet that these data will be on the way to the FDA. From the data we saw, it's hard to imagine how this drug would not be approved and become part of our standard treatment.

In the case of all good science, it brings up many other questions.

Patients had to be really high risk to enroll in this trial — not only stage II disease, but lymph nodes involved. If you had an ER-positive tumor, you had to have at least four lymph nodes involved. For triple-negative tumors, only one lymph node involved. For those who had neoadjuvant therapy, they still had to have residual disease.

What about those patients who are lower risk? Patients with ER-positive disease who have two or three lymph nodes involved have a substantial risk for recurrence. Patients with triple-negative disease who may have had primary surgery and are node negative but with a 2- to 3-cm tumor have a substantial risk for recurrence. Would we be comfortable expanding these data to those patients? I certainly would. We'll need to work through the details of the approval and the insurance authorizations to learn what's possible.

It also raises questions about whether we should be thinking about using these drugs earlier instead of a portion of chemotherapy, particularly in some of those lower-risk patients. I also predict that we are going to see neoadjuvant trials designed to look at these drugs more carefully in these patients.

For me, as a researcher, the best news here is that this trial was conducted. Think about it. This is not a common patient: germline mutation, high risk, node-positive disease. This trial required an international collaboration to get these results for us and our patients. We can now answer this sort of question with these rare patients, and we're going to be able to answer many more.

I'll be back with you again soon.

Kathy D. Miller, MD, is associate director of clinical research and co-director of the breast cancer program at the Melvin and Bren Simon Cancer Center at Indiana University. Her career has combined both laboratory and clinical research in breast cancer.

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Cite this: Kathy D. Miller. Olaparib Beneficial for BRCA-Mutated HER2-Negative Breast Cancer - Medscape - Jun 11, 2021.

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