New Treatment for HER2+ Survivors
For certain women with metastatic HER2+ breast cancer, life just got a little bit brighter – literally.
On January 29, the FDA granted approval to a new combination drug therapy – Tykerb (lapatinib), and Femara (letrozole) – for post-menopausal women with estrogen-receptive, HER2-positive (HER2+) metastatic breast cancer.
Studies released at the annual San Antonio Breast Cancer Symposium last December show that the Tykerb/Femara combination extends median progression-free survival by more than 5 months.
Whoa – before we take too deep a dive here, let’s back up and understand how this new drug combo works.
First, what’s HER2+ breast cancer? Well, cells do three things: they grow, they rest, and they repair themselves. Genes inside the chromosomes in your cells regulate their activity, telling them when to grow, and when to stop growing and rest. If the genes malfunction, the patterns of growth/rest/repair are disrupted.
In HER2+ breast cancer, there’s an excess of HER2 genes in the chromosomes of some of your cells. These genes tell the cells to grow extra protein receptors on their surface. With these extra receptors, the cells keep getting signals to grow, rather than to rest or repair. They grow much faster than the cells around them; this wild, uncontrolled growth turns them into cancer cells.
HER2+ isn't uncommon; about 25% of women diagnosed with invasive breast cancer have this type.
Typically, a woman with HER2+ cancer will receive Herceptin infusions every 3 weeks for a year. After that, she’ll be put on hormone therapy: an aromatase inhibitor (Armidex, Femara, Aromasin) if she’s post-menopausal; or tamoxifen, if pre-menopausal.
Unfortunately, because HER2+ cancer is more aggressive than most, it’s more likely to recur: to metastasize to other parts of the body. This is where Tykerb/Femara step in.
If a woman’s HER2+ cancer metastasizes, her oncologist will start measuring “progression-free survival” – i.e., how long the cancer remains dormant and doesn’t grow. Results of the clinical trial presented in San Antonio demonstrated that for women taking Femara alone, the median progression-free survival was 3 months.
But for women who took Tykerb in combination with Femara, this median progression-free survival was 8.2 months – nearly 3 times as long as with Femara alone.
So, are you a candidate for the Tykerb/Femara combination?
Yes, if you’re post-menopausal; your cancer is both HER2+ and hormone-positive; and it’s metastasized.
Researchers say that there’s “tantalizing evidence” that this same combination might work well for pre-menopausal women whose cancer metastasizes while they’re on tamoxifen. Dr. Edith Perez of the Mayo Clinic, who focuses her research on HER2+ breast cancer, says that “This is something that we want to help explore, because it could be potentially very important.”
Perez is also developing a study comparing the effectiveness of Tykerb/Femara to Herceptin, when used as adjuvant therapy (recurrence prevention) for HER2+ breast cancer survivors post-chemo.
One step at a time, we’re making gains in the fight against one of the more aggressive breast cancers: HER2+.