TDM-1 Trial Disappoints in HER2-Positive Breast Cancer

The gist: A clinical trial that tested a new drug called TDM-1 (Kadcyla) found disappointing results for patients with metastatic, HER2-positive breast cancer. The trial found that treatment with T-DM1 plus the drug pertuzumab is no better than treatment with trastuzumab plus chemotherapy. For more on TDM-1, see this recent news about its potential benefits for patients whose cancer has spread to the central nervous system (CNS).

“Results of the anticipated phase III MARIANNE trial found that HER2-positive metastatic breast cancer patients treated with trastuzumab emtansine (T-DM1) plus pertuzumab had similar progression-free survival (PFS) compared with those treated with trastuzumab plus a taxane-based chemotherapy.

“Though the trial met its noninferiority endpoint, showing a similar PFS in the first-line setting between the two combination therapies along with T-DM1 alone, it failed to demonstrate that T-DM1 performs better than trastuzumab plus chemotherapy.

“The study has been anticipated by clinicians as two of the treatment arms do not include a taxane, which often causes patients to lose their hair, among other toxicities. The full results of the study will be presented at a future medical meeting…

“ ‘In my opinion, given the substantial survival associated with [docetaxel plus trastuzumab and pertuzumab of over 56 months], it remains the current first-line standard regimen especially for those patients who have never been exposed to trastuzumab,’ said Hurvitz.”