RAD001 May Reverse Resistance To Herceptin In Metastatic Breast Cancer Patients

Ruzanna Harutyunyan's picture

New data from two early clinical studies show that RAD001 (everolimus) may overcome resistance to Herceptin (trastuzumab) in women with HER2-positive metastatic breast cancer. These results support the initiation of a Phase III clinical trial program to fully explore the potential of RAD001 (proposed brand name Afinitor) in breast cancer.

Two Phase I studies were presented today during the CTRC-AACR San Antonio Breast Cancer Symposium. Initial results from both studies were released earlier this year at the American Society of Clinical Oncology (ASCO) annual meeting.

Updated results from the first Phase I trial show that the combination of RAD001 with Herceptin and weekly Taxol (paclitaxel) halted tumor growth in 77% of patients with HER2-positive metastatic breast cancer with documented resistance to Herceptin. In addition, the data demonstrated the first complete response in the trial.


In addition, updated data from the second Phase I study show promising anticancer activity for RAD001 in combination with Herceptin and Navelbine (vinorelbine) in heavily pretreated Herceptin-resistant patients with HER2-positive metastatic breast cancer. In the study, RAD001 in combination with Herceptin and Navelbine halted tumor growth in 62% of patients.

"Data presented at this meeting affirm the potential of RAD001 to reverse Herceptin resistance and restore patient response to treatment," said Ruth O'Regan, MD, Emory University School of Medicine, Atlanta, GA. "These findings are important for patients with HER2-positive metastatic breast cancer who develop resistance to Herceptin."

Preclinical data have shown that RAD001, an inhibitor of mTOR, acts on the pathway that mediates Herceptin resistance and has the potential to help restore response in these patients. RAD001 works through direct antitumor activity and through its influence on two of the most important pathways for breast cancer, the erbB receptor and the HER2 pathways.

"We are encouraged by the benefit RAD001 provided to advanced breast cancer patients in these early trials," said Alessandro Riva, MD, Executive Vice President & Global Head of Development, Novartis Oncology. "Novartis is committed to further evaluating the potential of RAD001 in combination with Herceptin as a new treatment regimen in breast cancer, as well as studying its role in treating other tumor types."