Dr. Blackwell on the Impact of the CLEOPATRA and MARIANNE Studies in HER2+ Breast Cancer

Kimberly L. Blackwell, MD, medical oncologist, Duke Cancer Institute, discusses the lasting impact that the CLEOPATRA and MARIANNE studies have had on the treatment landscape in HER2-positive breast cancer.

CLEOPATRA was a phase III evaluation of pertuzumab (Perjeta) and trastuzumab (Herceptin) for patients with HER2-positive metastatic breast cancer. This study was important, says Blackwell, because the addition of pertuzumab to trastuzumab demonstrated a significant improvement in overall survival (OS).

MARIANNE compared the taxane/trastuzumab regimen with T-DM1 (ado-trastuzumab emtansine; Kadcyla) or T-DM1 plus pertuzumab, and showed that T-DM1 plus pertuzumab was not a significantly better treatment than T-DM1 alone. Moreover, says Blackwell, T-DM1 alone has demonstrated similar efficacy results to taxane/trastuzumab in terms of progression-free survival.

Despite those findings, Blackwell does not think that the MARIANNE study takes anything away from the CLEOPATRA results, as the addition of pertuzumab to the taxane/trastuzumab regimen significantly improves survival for these patients.

T-DM1 is still being investigated in ongoing trials. Results from the recent phase III TH3RESA trial showed that T-DM1 yielded an increased median OS compared with patients who received treatment of physician’s choice. Also, a phase II clinical trial at Dana-Farber Cancer Institute is currently looking to see if T-DM1 will yield less adverse events than a treatment regimen containing trastuzumab and paclitaxel (Abraxane). The investigators in this study hope to learn more about the long-term benefits and disease-free survival of patients treated with T-DM1, in comparison with patients who receive a combination of trastuzumab and paclitaxel.