by ecancer reporter Janet Fricker

The addition of cetuximab to chemotherapy delivered positive results in triple negative breast cancer (TNBC) concluded the BALI study presented in the Presidential Symposium at the ESMO Congress in Milan, Italy, 8-12 October 2010.

Approximately 15 to 18 % of breast cancers are “triple negative” which means that they do not express receptors for oestrogen, progesterone or HER2.  These tumours are associated with a particularly poor prognosis both because they tend to grow and spread through the body rapidly and also because due to the lack of receptors they do not respond well to hormone or anti-HER2 therapies. Cetuximab is a monoclonal antibody that specifically targets epidermal growth factor receptor (EGFR), a protein expressed by around half of all breast cancer tumours.

In the phase II study, 173 patients with metastatic breast cancer and triple negative disease were randomized to receive either cetuximab plus up to six three weekly cycles of cisplatin (n=115) or cisplatin alone (n=58). The study’s primary end point was the overall response rate. Cetuximab

Results show that an overall response rate of 20 % was seen in patients receiving the cetuximab/cisplatin combination compared to a response rate of 10.3% in the cisplatin alone arm (p=0.11).  Adding cetuximab to cisplatin more than doubled the median length of progression-free survival, from 1.5 to 3.7 months (HR 0.675, p=0.032).

“While the study did not meet its primary endpoint, we saw a doubling in progression free survival so to my mind it was a positive study. The take home message is that I’m convinced that cetuximab has a role in treating breast cancer, but I think that we need to design a more appropriate trial,” said José Baselga, the principal investigator of the study, from the Massachusetts General Cancer Center,   Boston, MA, USA. “In this advanced-disease population, this type of improvement is rarely seen and is highly significant.”

He added that triple negative breast cancer probably represents a number of poorly understood sub-groups of breast cancer. “If we work hard at identifying the different subtypes and identify the appropriate targets, we should be able to change the natural history of this disease.”

Cetuximab s already licensed for use with chemotherapy in colorectal cancer and squamous cell carcinoma of the head and neck.