Targeted therapy for iodine-refractory thyroid cancer

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Published: 29 Sep 2014
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Dr Makoto Tahara - National Cancer Center Hospital East, Kashiwa, Japan

Dr Tahara talks to ecancertv at ESMO 2014 about the development of a new targeted therapy for the treatment of iodine-refractory thyroid cancer.

Thyroid cancer is an extremely interesting situation because there are good therapies. You’ve been looking at patients with refractory thyroid cancer, iodine refractory thyroid cancer, what did you decide to do? What’s the context clinically, why did you need to do this?

In the past there are no effective therapies after radioactive iodine for differentiated thyroid cancer but recently development of a new targeted therapy is now increasing. So we medical oncologists take care with these patients now.

There has been some success with sorafenib so far but you’ve now got a very different compound, lenvatinib. What is this agent and what are you doing with it?

Lenvatinib is an orally available large kinase inhibitor of VEGFR, FGFR, PDGFRα and RET and KIT signalling pathway. Recently we presented our results from a fast phase III trial of lenvatinib. This trial demonstrated that lenvatinib significantly prolonged median progression free survival by 14.7 months compared to placebo.

Tell me about the protocol for this study.

The study population were radioactive iodine refractory differentiated thyroid cancer and it was a randomised clinical trial, a 2:1 ratio of patients receiving lenvatinib or placebo.

Looking at the control group and the treatment group, what was the improvement, the change, in progression free survival?

The placebo arm the median progression free survival was only approximately 3 months; in the lenvatinib arm it was 18 months.

It looks, on the face of it, a massive change.

Yes, that’s right.

What do you think about this?

When I saw the results at first I was very surprised at this result.

So what would you say to clinicians at this point?

Yes, lenvatinib also has excellent clinical activity - response rates are 64%, that’s very amazing. This provides a patient benefit to improve symptoms and a better quality of life.

You’ve said improve symptoms, so what about toxicity? Was there any undue toxicity?

The main toxicities are hypertension and proteinuria and diarrhoea. But basically it is manageable by dose reduction or dose interruption.

And the improvement in progression free survival, what could that mean in terms of overall survival?

Unfortunately there is no difference in overall survival because most of the patients crossed over to receive the lenvatinib treatment in the placebo arm.

What should doctors be doing now?

Lenvatinib should be considered for the radioactive iodine refractory differential cancer patients at first.

And the take home message for doctors around the world, what would that be?

Lenvatinib extends approximately 15 months progression free survival. That is a very amazing result. So please pay attention to this drug.