9 weeks vs 1 year adjuvant trastuzumab in combination with chemotherapy

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Published: 4 Jun 2017
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Prof Valentina Guarneri - Università degli Studi di Padova, Padua, Italy

Prof Guarneri speaks with ecancer at ASCO 2017 about results from a phase III multicentre trial of  trastuzumab in adjuvant setting with chemotherapy for 9 weeks vs 1 year for patients with HER2 breast cancer.

The 5-year disease free survival rate was 87.5% for the long arm compared to 85.4% for the shorter arm.

She notes that the shorter length of treatment with adjuvant trastuzumab significantly lowers risk of cardiac events.

The reduced overall cost of shorter treatment may also lower barriers to treatment access.

ecancer's filming has been kindly supported by Amgen through the ECMS Foundation. ecancer is editorially independent and there is no influence over content.

The question is related to the duration of trastuzumab in the adjuvant setting. In our trial we compared 9 weeks of adjuvant trastuzumab combined with chemotherapy to the standard one year trastuzumab, again combined with chemotherapy.

A big study?

It’s a big study, 1,253 patients were randomised and on Monday we will present the disease free survival analysis after 5.2 years of median follow up.

That’s a big trial asking that sort of question. What’s the answer?

At the time of the analysis the five year disease free survival rate was 87.5% for the long arm versus 85.4% for the short arm. As I mentioned before, this was a non-inferiority trial and the margin of the confidence interval crossed the margin for non-inferiority. Soon the basis of this analysis we cannot claim the non-inferiority for the short arm. However, in the trial we planned also an analysis based on the Bayesian approach and according to this analysis this study has almost an 80% probability of demonstrating that short treatment is not inferior to long treatment. The overall survival curves are completely superimposable. Another important point is the cardiac safety because the long treatment arm was associated with a higher rate of significant cardiac events. So on the basis of our trial we cannot say that the short trastuzumab administration can be offered to all patients but maybe can be an option for those patients who are at high risk of cardiac toxicity or, for instance, for patients who are at a lower risk of relapse because they have node negative disease.

These data are also very important when thinking about the costs of treatment because we know that a huge proportion of patients worldwide are not offered the trastuzumab for one year because of the cost. So in our view these data can be helpful to lower the barrier to access to these drugs.