TDM-1 Heavy Hitter in Heavily Treated Breast Cancer

Joseph Gligorov, MD, PhD; Javier Cortés, MD, PhD


October 07, 2013

In This Article

TDM-1 and the 'Amazing' TH3RESA Results

Dr. Cortés: The TH3RESA trial had a very interesting clinical trial design because TDM-1 was compared with the treatment of physicians' choice. Patients should have received at least 2 previous lines of therapy for metastatic disease, and all patients should have received trastuzumab and lapatinib and were progressing on these agents. This was compared with whatever their oncologists thought was the best treatment for them. The results were amazing. Patients who received TDM-1 had double the progression-free survival. The hazard ratio was 0.53, and the median progression-free survival went from just over 3 months to more than 6 months. These data are absolutely exciting. Furthermore, the overall response rate was increased from 9% to 31%, according to the data we have from phase 2 trials in patients who received trastuzumab and lapatinib.

Finally, the overall survival data were also amazing. This was an interim analysis, and we will not have the final analysis because once the EMELIA data appeared, patients who received the treatment of physician choice were able to cross over to TDM-1. Mature data in terms of overall survival will not be available because of this crossover. In terms of toxicity, we did not have any unexpected toxicity according to the TDM-1 data. Grade 3 and 4 toxicities with TDM-1 were lower than with the treatment of physicians' choice.

Dr. Gligorov: Clearly this is important information, not only the results with the TDM-1, but the treatment strategy in general, showing us that we have to continue to keep putting pressure on the HER2 pathway, even if patients have already received 2 or more lines of therapy. In the TH3RESA trial, there is a median number of full-line chemotherapy regimens using anti-HER2 treatment, so that means that clearly, even in a quite advanced situation, we have benefit from keeping the pressure on, particularly with this drug.

Dr. Cortés: I completely agree. We have to rapidly move these drugs -- TDM-1 and pertuzumab -- into the adjuvant or the neoadjuvant setting to translate these benefits in metastatic disease to cure more patients. This is our main objective.


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