Genentech posts updated survival data from pivotal Herceptin studies

Two randomized, controlled phase III studies evaluated four cycles of doxorubicin and cyclophosphamide followed by paclitaxel, either every three weeks or weekly for 12 weeks, compared with the same regimens plus 52 weeks of Herceptin (beginning with the first dose of paclitaxel) in nearly 4,000 patients with HER2-positive breast cancer.

Data presented at the 43rd Annual Meeting of the American Society of Clinical Oncology (ASCO) showed that, with median follow-up of nearly three years, the addition of Herceptin to standard adjuvant therapy significantly improved overall survival in women with HER2-positive, node-positive breast cancer, compared to patients who received standard adjuvant therapy alone.

Results showed that the addition of Herceptin to standard adjuvant therapy continued to significantly reduce the risk of breast cancer recurrence, the primary endpoint of the studies, by 52% in women with HER2-positive, node-positive breast cancer, compared to patients who received standard adjuvant therapy alone.

At four years of follow-up, 85.9% of women treated with Herceptin plus chemotherapy were disease-free, compared to 73.1% of women treated with chemotherapy alone. The demonstrated treatment benefit of Herceptin plus chemotherapy was consistent across many important patient subgroups.

Notably, despite some patients crossing over to the Herceptin-containing arm, the additional follow-up data presented at ASCO showed an improvement in overall survival; 92.6% of women treated with Herceptin plus chemotherapy were still alive at four years of follow-up, compared with 89.4% of women treated with chemotherapy alone.

This updated survival analysis showed a statistically significant 35% reduction in the risk of death, which is equivalent to a 54% improvement in overall survival.