Breast Cancer Drug Approved as 1st Treatment

October 1, 2013

News Review From Harvard Medical School -- Breast Cancer Drug Approved as 1st Treatment

Women with one type of breast cancer now will be able to get drug treatment before surgery. The U.S. Food and Drug Administration (FDA) has expanded the approved uses for the drug Perjeta (pertuzumab). It now is approved for early-stage as well as advanced HER2-positve breast cancers. HER2 receptors are proteins found on the surface of most breast cancers. They provide docking stations for a hormone that can increase breast cancer growth. Cancers with an excess number of HER2 receptors are called HER2-positive. Pertuzumab blocks the receptors so the hormone can't attach to the cells and spur them to grow. The drug already was approved for treatment of HER2-positive cancers that had spread. Now women with early-stage cancers can receive it as their first treatment. This is the first breast-cancer drug approved for use before surgery. Genentech, a division of Roche Group, makes pertuzumab. The FDA granted "accelerated" approval for this new use of the drug. Genentech must conduct more research to ensure that long-term side effects do not outweigh benefit. HealthDay News wrote about the approval September 30.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

In the 1950s, standard treatment for breast cancer was a radical mastectomy. This meant removal of the entire breast, surrounding lymph nodes and tissues underneath the breast. Most often this was followed by radiation.

By the 1970s, chemotherapy had been added to the mix. Powerful drugs killed rapidly dividing cancer cells. But the treatment also killed normal cells. Side effects could be horrendous. Infections from bone marrow wipeout could be deadly.

These approaches offered women the best chances of breast cancer cure. And indeed lives were saved. But how many women did not need such aggressive treatment because more limited treatment would have worked as well? In other cases, the treatment was destined not to work from Day 1 because the cancer was resistant or had already spread too far.

Cancer doctors long suspected that breast cancers aren't all the same. They knew some could be eliminated safely by surgery alone. Others might respond to hormone treatments. And a few might need chemotherapy.

But doctors had limited information to choose the best treatment for their patients. So most women with breast cancer were treated aggressively.

Now, thanks to advances in molecular biology, doctors are better able to make those distinctions. Breast cancer research today is focused on identifying the specific genes and proteins of breast cancer cells. This knowledge can help distinguish the resistant cancers from those that are easier to wipe out.  

One of these proteins is called the HER2 receptor. It is found on normal breast cells and most breast cancer cells. The HER2 receptor is a docking station for a hormone that can spur breast cancer growth.

Women with many HER2 receptors have a worse prognosis. This happens in about 1 of every 5 breast cancer cases. It's called HER2-positive breast cancer.

If a woman has HER2-positive breast cancer, her doctor will almost surely recommend surgery. Most often this will be a lumpectomy. Radiation therapy could follow. Usually a drug that directly attacks the HER2 will be part of the mix.

Now some women may be able to avoid, or at least delay, surgery and radiation. The U.S. Food and Drug Administration has approved early use of a drug called pertuzumab. This drug "plugs up" the HER2 docking stations. It keeps the hormones from binding to HER2 and causing cancer cells to grow.

Pertuzumab was approved last year, but only for later-stage HER2-positive cancers (those that had spread). Now women with early-stage cancers can get the drug as their first form of treatment.

What Changes Can I Make Now?

Breast cancers are as diverse as the women who have them. So, if you are diagnosed with breast cancer, review all the details of your biopsy and staging results with your cancer doctor.

Key details include:

• The cell type of the cancer -- Some abnormal breast cells that have been labeled as cancer don't behave like typical breast cancers.
• The size of the cancer -- A smaller size usually means a better chance of cure.
• The presence or absence of tumor markers -- Is the tumor positive or negative for estrogen, progesterone and/or HER2 receptors?
• Evidence of spread beyond the breast – Nearby lymph nodes will be checked for cancer cells.

These are just the basics involved in designing the best treatment plan for you.

What Can I Expect Looking to the Future?

Targeted therapies for breast cancer will continue to improve. This will lead to higher cure rates and fewer side effects from treatment.