Breast Cancer Update

Finding Cures: What's New in Breast Cancer Treatment?

New Class of Drugs
Promising for BRCA-related Cancers

New drugs called PARP inhibitors appear to have a lot of promise against cancers caused by BRCA1 and BRCA2 gene mutations.

Women who carry these mutations are at a higher risk of developing breast and ovarian cancers. The gene mutations are also linked to some prostate cancers in men. Because of the way PARP drugs work, scientists hope they can be used to target the cancer cells without destroying healthy cells, this would mean fewer harsh side effects.

In a small phase I study, researchers at the Institute of Cancer Research in Sutton, England tested the action of a PARP drug called olaparib in 20 men and 40 women with different types of cancer – breast, ovarian, colorectal, prostate, melanoma, as well as some other types. About one-third of the people in the study had BRCA mutations.

Twelve patients with BRCA gene mutations saw their tumors shrink or stop growing. These patients all had breast, ovarian, or prostate cancer. The drug had no effect on patients who were not BRCA1 or BRCA2 carriers. Side effects were minimal compared to traditional chemotherapy drugs.

The findings are so promising they were published recently in The New England Journal of Medicine, which typically doesn't publish results from early phase I studies. An accompanying editorial called the drugs "a new direction in cancer-drug development."

And PARP drugs appear to be effective against other types of breast cancer, as well.

Another study, which was presented recently at the Annual Meeting of American Society of Clinical Oncology, found that the PARP drug BSI-201 improved survival in women with triple-negative breast cancer compared to traditional chemo. Because triple-negative breast cancer lacks certain receptors, it doesn't respond to hormone therapy or drugs that target HER2, such as Herceptin^®.

While these findings are very encouraging, PARP drugs are still in the early stages of development and more testing is needed.

Lapatinib May Work Against Certain Inflammatory Breast Cancers

Women with HER2+ inflammatory breast cancer who haven't responded to other cancer treatments may benefit from lapatinib (Tykerb^®), according to results from a study published recently in The Lancet Oncology.

Inflammatory breast cancer (IBC) is a rare and aggressive type of breast cancer that accounts for about 1% to 3% of all breast cancers diagnosed in the United States. It's more likely to grow quickly and to have spread to nearby lymph nodes by the time it is diagnosed than other types of breast cancer, and the outlook for IBC patients is generally not as good.

Because IBC isn't typically associated with a breast lump, it's difficult to diagnose early. Symptoms may include breast swelling; itching; a pink, red, or colored area, sometimes with a texture like the skin of an orange; and the breast feeling warm to the touch.

Women with this type of breast cancer are typically treated with a combination of chemotherapy drugs, trastuzumab (Herceptin), and radiation. If the cancer doesn't respond to these treatments, these women don't have many other options.

This study looked at lapatinib's effect on 126 women with HER2+ inflammatory breast cancer who were previously treated with some combination of chemotherapy, Herceptin, or radiation, as well as 15 women who did not have HER2+ IBC. It was funded by GlaxoSmithKline (the maker of lapatinib) and led by researchers from several institutions, including the Chaim Sheba Medical Center, Sunnybrook in Toronto, and Duke University Medical Center.

The researchers found that cancers in 49 of the 126 women responded to the drug -- and those patients survived longer than those who didn't respond. More than half of the women who had a response to the drug saw results within 2 months. None of the patients saw their disease disappear, although one patient saw her skin improve markedly.

Common side effects included diarrhea, rash, tiredness, nausea, appetite loss, shortness of breath, vomiting, and back pain. Diarrhea was the most common. Forty-five of the total 141 women in the study had some serious side effects – shortness of breath, fluid collection around the lungs, and fever – but in most cases these were not thought to be related to treatment with lapatinib. Five women died from side effects that may have been related to treatment with lapatinib.

While the study results are promising, the drug is not yet FDA-approved for this use. Lapatinib is also being studied for use against cancers of the prostate, brain, liver, and ovaries, as well as other cancers.