4 Questions with See Phan: Discovering New Therapies in Breast Cancer

As a practicing physician and cancer researcher for more than 20 years, See Phan is all too familiar with the need for innovative new treatment options, especially for breast cancer.

“Patients and providers are particularly eager to obtain therapies that slow tumor growth while also supporting a person’s quality of life,” he says. “Fortunately, the treatment landscape is advancing quickly for people with breast cancer.”

See, Vice President of Oncology Clinical Development at Gilead, took a moment to walk us through some of the new innovations in breast cancer and the work underway at Gilead Oncology, where the vision is to help bring more life to people with cancer.

Q: What is the focus of Gilead’s breast cancer development program?

We’re focused on addressing the biggest gaps in treatment, which includes developing therapies for several types of breast cancer. Our development program is designed to understand where our therapies are showing efficacy, and then to move into earlier lines and stages with the potential for curative intent.

Treatment options are expanding, such as antibody-drug conjugates (ADCs) that can deliver tumor-destroying compounds directly to cells. ADCs are maturing and improving, allowing for use against a broader array of tumor types.

At Gilead, we initially focused on metastatic triple-negative breast cancer, an extremely aggressive type of cancer, and we’re also working to provide options for people living with pre-treated HR+/HER2- metastatic breast cancer – another difficult-to-treat type of breast cancer.

Q: What is the outlook for people living with HR+/HER2- breast cancer?

HR+/HER2- breast cancer accounts for approximately 70% of all diagnoses, meaning that about 1.5 million people are diagnosed worldwide each year.

About one-third of people who are diagnosed go on to develop metastatic disease. Metastatic HR+/HER2- breast cancer has a disappointing 5-year survival rate of around 30%, making it critical that new options are developed for people with this disease – especially for older women and for Black women, who have a particularly poor prognosis.

Once a person with metastatic HR+/HER2- breast cancer progresses on endocrine-based therapies, which most will, they have traditionally been left with only chemotherapy as an option. At this point, median survival is only approximately one year, and this decreases with each subsequent line of therapy. Treatment changes from endocrine-based therapies to chemotherapy, in addition to cycling chemotherapies is also associated with declining quality of life, which has a substantial impact later in therapy. We need to meet the needs of these patients with more effective treatment options.

Q: Why are options other than chemotherapy so important?

I’ve learned through my clinical experience that people with metastatic HR+/HER2- breast cancer prioritize quality of life. They want to avoid the side effects and other treatment stresses of chemotherapy for as long as possible. As physicians consider treatment options, we need to think about the side effect profile balanced with efficacy and quality of life.

I’m hopeful as more treatment options become available, such as ADCs, we can help stop tumor growth with fewer side effects for patients as compared to traditional chemotherapy.  

Q: What does the future of cancer therapies overall look like at Gilead?

It’s an exciting time here, as we have more than 50 active or planned cancer clinical trials, including many in breast cancer, for 2023. We’ve gained six new indications for our cancer therapies in the last two years, and we anticipate adding 10 additional indications by 2026.

I came to Gilead because I understood the need to bring more options to patients and saw promise in what the company was building. I truly believe that our therapies have the potential to help transform care and improve quality of life measures for people living with many different types of cancer. I’m excited for the opportunity to do my part to improve care for people with cancer, including metastatic HR+/HER2- disease.

Note: a version of this piece appears in STAT as sponsored content.