Genomics and You: What Treatments are Available? (3 of 4)

There is no question that genetics has become a hot topic in medicine. It seems that every week there is an article about a new genetic test, or another person throwing around the term “inherited risk”. These terms can seem scary at first, but with a bit of brushing up, you can use them to your advantage in managing your healthcare.

      To help along the way, Tigerlily is bringing the basics right to your laptop. We’ve partnered with Genomic Health to offer a 5-part blog explaining the ins and outs of breast cancer genetics and genomics. Read on for more information about inherited risk, the different types of tests offered and how they can help with treatment, and more.

The purpose of personalized medicine is to determine how best to treat the patient’s specific tumor. What are some of the treatments a doctor may prescribe, depending on the patient’s specific type of breast cancer? While treatment options may vary based on the cancer subtype, it is important to note that there are treatment options are available for both early and late stage breast cancer patients.

IF A TUMOR IS HER-2 POSITIVE

If a patient has HER-2 positive cancer, it indicates that the tumor is being stimulated to grow by an excess of HER-2 proteins. If a test shows that the tumor is HER-2 positive, a doctor may prescribe any of the following treatments.

1. TRASTAZUMAB (HERCEPTIN) –  Trastuzumab can be used for early or advanced breast cancer, either on its own or in combination with chemotherapy. In early-stage breast cancer, it is typically given for 6 to 12 months; in more advanced stages, it is given for as long as necessary.
2. PERTUZUMAB (PERJETA) – Pertuzumab can also be used for either early or advanced breast cancer, and may be used alongside trastuzumab and chemotherapy. When used for early-stage breast cancer, it is generally given before surgery.
3. ADO–TRASTUZUMAB (KALYRA, also known as TDM-1): Ado-trastuzumab is prescribed to women with advanced breast cancer, who have already received trastuzumab and chemotherapy.
4. Lapatinib (Tykerb):  Lapatinib is used for advanced breast cancer. It can be used in conjunction with certain chemotherapy drugs, trastuzumab, or hormone therapy drugs.
5. Neratinib (Nerlynx):  Neratinib is used for early-stage breast cancer, and is prescribed to women who have taken trastuzumab for one year. Neratinib itself is then generally taken for one year. Some clinical trials have shown evidence that it may be beneficial for advanced breast cancer, too.

IF A TUMOR IS HORMONE-RECEPTOR POSITIVE

A tumor that is “hormone-receptor positive”is one that is being stimulated to grow either by estrogen and/or progesterone. Treatment options may include:

1. EVEROLIMUS (AFINITOR) – Everolimus is used for advanced-stage, hormone-receptor-positive, HER-2 negative breast cancer. It is prescribed for women who have already undergone menopause. If a patient’s cancer grew during or just after treatment with the aromatase inhibitors letrozole or anastrozole, a doctor will typically prescribe everolimus together with a different aromatase inhibitor, exemestane (Aromasin), instead.
2. CDK4/6 INHIBITORS – CDK4/6 inhibitors are a special class of drugs. Their role is to disable a certain class of proteins, known as cyclin-dependent kinases (CDKs), that help breast cancer cells to reproduce. CDK4/6 inhibitors are prescribed for advanced, hormone-receptor-positive, HER-2 negative breast cancer. There are three main CDK4/6 inhibitors:
3. Palbociclib (Ibrance) – this CDK4/6 inhibitor may be used by women who have not yet undergone menopause (or who have just started menopause), but they must take other drugs while on palbociclib to prevent estrogen production in the ovaries. Palbociclib can be given alongside fulvestrant.
4. Riboclicib (Kisqali) – Ribociclib is approved for women who have not yet undergone menopause, and can be used along with an aromatase inhibitor. Women on ribociclib will need to take other drugs simultaneously to prevent estrogen production in the ovaries.
5. Abemaciclib – Abemaciclib is used on its own. It is prescribed for women who have received hormone therapy and chemotherapy in the past.

IF A PATIENT IS BRCA-1 OR BRCA-2 MUTATION POSITIVE

If a breast cancer patient has a BRCA-1 or BRCA-2 mutation, the doctor will typically prescribe a type of drug known as a PARP inhibitor. PARP inhibitors work to disable PARP proteins, which help to fix damaged DNA—a role that the BRCA genes fill, too. With neither the PARP proteins nor the BRCA genes working properly, the cancer cells will die as a result of the combination of PARP inhibitor and the pre-existing BRCA mutation.

There are two PARP inhibitors currently used: Olaparib (Lynparza) and talazoparib (Talzenna). Both are used for metastatic, HER-2 negative breast cancer, and are prescribed after chemotherapy has been administered. They are indicated for women with BRCA mutations.

Olaparib may be used for hormone-receptor positive breast cancer, even after hormone therapy.