Comment: MONARCH 3 trial: Abemaciclib for advanced breast cancer

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Published: 10 Sep 2017
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Dr Evandro de Azambuja - Jules Bordet Institute, Brussels, Belgium

Dr de Azambuja talks with ecancer at the ESMO 2017 Congress about the data presented by Dr Angelo Di Leo from the MONARCH 3 trial looking at abemaciclib as initial therapy for patients with HR /HER2- advanced breast cancer. 

For more information watch the press conference, and Dr Di Leo spoke with ecancer about the data here

Supported by a grant from Pfizer Inc.

The data is very interesting because it represents one more option of treatment for patients with metastatic breast cancer who have hormone receptor positive, HER2 negative breast cancer. What they showed is an improvement in median progression free survival with the addition of CDK4/6 inhibitors to endocrine therapy. This goes in the same line with the other trials that have been presented already and published showing an improvement in median progression free survival with the addition of this class of drugs to endocrine therapy. So this represents a huge benefit for patients.

We still do not have data on overall survival; the trials are collecting this but it will take longer. But in terms of median progression free survival it’s very impressive. In terms of overall response rate they also improved the response rate for these patients. In terms of side effects, as discussed, they have a difference in side effects with this one presented today, abemaciclib, giving a little bit more diarrhoea than the others, palbociclib and ribociclib, that give more neutropenia and febrile neutropenia.

So in terms of treatment they have a lot of efficacy in metastatic breast cancer and they represent a good option for patients. What we still are not clear is in terms of biomarkers to select which are the patients who would benefit or not benefit from these drugs. Because at the end of the day they are expensive drugs, they have side effects, but we still cannot differentiate a group of patients who would be the best to use or not to use those patients.