Breast Cancer Coverage from Every Angle

Final Results of MARIANNE Trial of T-DM1 in HER2-Positive Advanced Breast Cancer

By: Kelly M. Hennessey, PhD
Posted: Wednesday, October 9, 2019

Based on the final results of the randomized, phase III MARIANNE trial, trastuzumab emtansine (T-DM1) may be an effective first-line treatment option for patients with HER2-positive metastatic breast cancer who are considered to be unsuitable for taxane-based therapy. However, the median overall survival with T-DM1 as well as with T-DM1 plus pertuzumab was found to be noninferior—but not superior—to that with trastuzumab plus a taxane. In addition, patients experienced fewer treatment-related side effects with T-DM1 and a longer time to patient-experienced neurotoxicity symptoms. Edith A. Perez, MD, of the Mayo Clinic Cancer Center, Jacksonville, Florida, and colleagues published the results of their study in Cancer.

The study included a total of 1,095 patients and was designed to evaluate the safety and efficacy of T-DM1 with a placebo and T-DM1 with pertuzumab. In the control arm (n = 365), 257 patients received trastuzumab plus docetaxel and 96 patients received trastuzumab plus paclitaxel. Overall, 367 and 363 patients were randomly assigned to T-DM1 and T-DM1 plus pertuzumab, respectively.

At the final analysis, the median overall survival was 50.9 months in the control group, 53.7 months in the T-DM1 group, and 51.8 months in the T-DM1 plus pertuzumab group. None of the analyzed subgroups showed a benefit with one treatment compared with another. As a whole, patients treated with trastuzumab emtansine had a favorable tolerability profile in comparison to trastuzumab plus a taxane.

Disclosure: The study authors’ disclosures can be found at

By continuing to browse this site you permit us and our partners to place identification cookies on your browser and agree to our use of cookies to identify you for marketing. Read our Privacy Policy to learn more.