An examination of the real-world data supporting the use of tucatinib for patients with metastatic HER2+ breast cancer in Europe.
Volkmar Mueller, MD: My experience with tucatinib is driven by my participation in the HER2CLIMB trial. We had several patients in the trial. Many were from Germany, and I am unsure about what other countries patients came from. I have a feeling that it is good and manageable. After that, there came an expanded or early access program before the approval. We have also had several patients utilize open-label, non-placebo-controlled treatments on that combination, so it was effective from my limited experience.
One question we have is how do these data fit into data from the real world? One of my clinical and research interests is brain metastases because there is an unmet need in regard to treatment for that. It is an impairment and decreases patients’ quality of life and life expectancy. We have set up a registry for brain metastases in Germany, which includes more than 3600 patients. In our first publication 1½ years ago, with almost 2000 patients, we saw that the overall survival after the diagnosis of brain metastases was approximately 11 months. This is also in line—it may be a bit different but not completely different—with the French data. They have just found the overall survival of the entire patient crowd, not only those with the HER2 [human epidermal growth factor receptor 2]–positive subtype, which was 8 months after the diagnosis of brain metastases.
The HER2CLIMB trial showed that overall survival, after the start of therapy for brain metastases, was 18 months. I do not know if you can compare it, but it does look a little better, given that the standard arm was only 12 months. There was an overall survival benefit with tucatinib for patients with active brain metastases at almost half. The hazard ratio was 1.5, so it really set the risk for dying to 50%.
Thomas Bachelot, MD, PhD: I would like to discuss my experience and how it relates to the real-world data. For the moment, considering real-world data, we see this combination is quite small in France because we can use it only from 4 to 6 months. We do not have a lot of patients who were treated with this combination outside the clinical trial. I have some patients who have been treated with this combination after the clinical trial, but most of my patients were treated during the clinical trial. I do not see many differences. It is quite efficient for patients. We see some responses, as shown in the HER2CLIMB study. With regard to brain metastases, this combination is very nice.
We have had very good control of the treatment of our patients with brain metastases for a long time, as I told you before, with few toxicities. Our feeling is that it is really an improvement. This treatment is an improvement that will better treat our patients, especially those with brain metastases that have undergone multiple lines of treatment already. I do not have much experience regarding the real-world utilization of this molecule because it has been studied for such a short time, but the results are very much in line with what has been published in the HER2CLIMB study.
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