Allergic reaction to Herceptin

[jpuk]

I was diagnosed in December 2004 with Inflammatory Breast Cancer, a rare and particularly aggressive variety of this vile dsease; there followed chemotherapy, mastectomy and currently radiotherapy. Post-op pathology revealed 5 of 13 nodes positive but mercifully no evidence of extranodal or vascular invasion.

Because of the advanced nature of the diagnosis I have been put on Herceptin and have now had 3 treatments. I was warned to expect a 'flu-type reaction, but each session has been completely uneventful. My consultant oncologist has now told me that this is a good sign, and indicates there must be few if any cancer cells left as it is the interaction of the Herceptin antibody with the protein on the cancer cells which causes allergic reaction, i.e. it is not what it is but what it does that sets up reaction. This sounded like good news, but after the consultation I recalled that the more less senior doctor who went throught he consenting process with me before treatment started had said that an allergic reaction is caused because Herceptin is a "humanised" product based on a substance originally derived from mice!

I shall raise the issue when I see the consultant again next week but meanwhile I wonder if anyone else has discussed or read about the causes of allergic reaction to Herceptin?