Researchers have presented the combined results of two trials that compared adjuvant chemotherapy with or without concurrent Herceptin ( Trastuzumab ) in women with surgically removed HER2-positive breast cancer.

The studies showed Herceptin therapy to be highly superior to standard treatment, reducing recurrence of cancer by half.

The findings are published in the The New England Journal of Medicine.

“ Herceptin has changed the treatment of breast cancer,” says Edith Perez, who is the co-director of Mayo Clinic’s Multidisciplinary Breast Clinic in Jacksonville. “ When we started this study, I knew in my heart results would be positive, but this by far exceeded my expectations.”

Of the 2,043 patients enrolled in NSABP ( National Surgical Adjuvant Breast and Bowel Project ) trial B-31 and 1,633 patients enrolled in the two reported treatment groups of the North Central Cancer Treatment Group ( NCCTG ) trial N9831 by the end of 2004, complete follow-up information was available on 3,351 patients.

Two hundred sixty-one women in the control group ( 1,679 patients ) had a recurrence of breast or other primary cancer as compared to 133 in the group receiving Herceptin..

At three years, 90.4 percent of women receiving Herceptin were disease free, compared to 81.5 percent of women in the control group.

There also was a measurable reduction in the development of other non-breast primary cancers in the B-31 trial for women receiving Herceptin. Overall survival also appeared to be impacted, with only 62 deaths in the Herceptin group as compared with 92 in the control group.

Perez and her co-investigators found convincing evidence that women with HER2-positive breast cancer can now be treated more effectively.

“ A million women each year are diagnosed with breast cancer throughout the world, and approximately 25 percent of them have HER2 tumors,” said Perez. “ To be able to find a treatment that impacts the lives of so many is a huge success for the cancer research community.”

The NCCTG trial N9831, of which Perez was the primary investigator, was a cooperative effort with the Eastern Cooperative Oncology Group ( ECOG ), the Southwest Oncology Group ( SWOG ), and the Cancer and Leukemia Group B ( CALGB ).
It compared three chemotherapy regimens, two that included Herceptin therapy — one dosage concurrent with weekly Paclitaxel ( Taxol ), the other after completion of Paclitaxel.

The NSABP trial B-31 compared one chemotherapy regimen against the same regimen with weekly Herceptin and tri-weekly ( or weekly ) Paclitaxel.

Investigators determined that the treatments being compared were similar, and results from the two studies were combined to form a joint analysis, excluding the NCCTG N9831 trial group that looked at Herceptin administered sequentially after Paclitaxel.

Herceptin combined with Paclitaxel after Doxorubicin and Cyclophosphamide improves outcomes among women with surgically removed HER2-positive breast cancer.

Source: Mayo Clinic, 2005


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