We started off the San Antonio Breast Cancer Symposium this year with several discussions on new studies that analyze combined therapies in breast cancer.
Cancer cells are so complicated and have such a vast network that when you block one pathway with a targeted agent, the cells will try everything they can to get around it – or resist treatment. By combining targeted therapies, we hope to circumvent that.
Herceptin has been used for years to treat HER2-positive breast cancer, but in metastatic breast cancer, the cancer cells eventually become resistant to the drug and begin to grow again.
In the Neo-ALTTO study, a combination of two HER2-targeted agents, Herceptin and Tykerb, were compared with Herceptin alone. These agents were given before surgery–the neoadjuvant setting. When you combine the two drugs compared to just one drug, the number of patients who had a complete pathological response–a complete disappearance of the cancer–is much higher. What’s important about this is when you have a higher complete pathological response, overall survival is higher and the number of people who have a recurrence and die is lower.
It’s important to see if the response rates can actually be linked to the long-term recurrence-free survival using this model of combination biological therapy before surgery–something the FDA is looking at to possibly approve future drugs for use in cancer treatment.
The results of the Neo-ALTTO study were presented earlier and it had been shown to improve pathological complete response. And with longer follow-up, fewer people had a recurrence. It’s not quite statistically significant yet, but in hormone-negative patients, those patients did have a better recurrence rate if they had a complete pathological response. This is an important finding for us because it tells us we can study newer drugs in a much faster time frame.