Lapatinib May Work Against Certain Inflammatory Breast Cancers

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Women with HER2+ who haven't responded toother cancer treatments may benefit from , accordingto results from a phase II study published this month in The Lancet Oncology.

Inflammatory breast cancer (IBC) is a rare and aggressive typeof breast cancer that accounts for about 1% to 3% of all breast cancersdiagnosed in the United States. It's more likely to grow quickly and tohave spread to nearby lymph nodes by the time it is diagnosed thanother types of breast cancer, and the prognosis (outlook) is generallynot as good. It isn't typically associated with a breast lump, whichmakes it difficult to diagnose early. Symptoms may include breastswelling; itching; a pink, red, or colored area, sometimes with atexture like the skin of an orange; and the breast feeling warm to thetouch.

Patients with inflammatory breast cancer often have too muchof a protein called human epidermal growth factor receptor-2 (HER2),which promotes the growth of cancer cells. Those patients are typicallytreated with a combination of chemotherapy drugs, , and radiation. If the cancer doesn't respond to thosetreatments, HER2+ inflammatory breast cancer patients don't have manyother options.

This study looked at lapatinib's effect on 126 women withHER2+ inflammatory breast cancer who were previously treated with somecombination of chemotherapy, Herceptin, or radiation, as well as 15women who did not have HER2+ IBC. It was funded by GlaxoSmithKline (themaker of lapatinib) and led by researchers from several institutions,including the Chaim Sheba Medical Center, Sunnybrook in Toronto, andDuke University Medical Center.

The researchers found that 39% of the 126 women responded tothe drug -- 1500 mg by mouth each day -- and of that group, the medianoverall survival was 18.4 months, compared to 8.4 months for patientswho didn't respond. More than half of the women who had a response tothe drug saw results within 2 months.

Patients who responded to the drug went an average of 25 weeksbefore the cancer started growing again. And at 6 months, 22% of HER2+patients were still progression-free. Patients who previously respondedto trastuzumab and responded to lapatinib had the longest medianoverall survival, followed by those who responded without priortrastuzumab treatment. None of the patients saw their diseasedisappear, although one patient saw her skin improve markedly.

Of the whole group of 141 women, common side effects –reported by at least 10% or more of the patients – included diarrhea,rash, fatigue, nausea, anorexia, shortness of breath, vomiting, andback pain. Diarrhea was the most common. Forty-five of the 141 womenexperienced some serious side effects – shortness of breath, fluidaccumulation around the lungs, and fever – but these were not thoughtto be related to treatment with lapatinib in most cases. Five womendied from side effects that may have been related to treatment withlapatinib.

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

For more information about lapatinib, see our . For more information about this type of breast cancer,see .

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Citation: Published in the June 2009 issue of The Lancet Oncology.First author: Bella Kaufman, MD, The Chaim Sheba Medical Center, TelHashomer, Israel.