ECC 2015

Results of a placebo­ controlled study of tasquinimod in men with metastatic castrate resistant prostate cancer

Dr Michael A. Carducci - Johns Hopkins University, Baltimore, USA

Metastatic castrate resistant prostate cancer is an important issue, you’re addressing it with a new agent. Can you tell me what you’ve been doing?

We had a new agent, tasquinimod, which is an agent that targets the tumour microenvironment so it has multiple activities both as an immune modulator, an antiangiogenic and has anti-metastatic activity. So we looked at it as a single agent in a phase III double blind randomised trial to determine whether or not it could improve progression free survival.

You already had phase II results, didn’t you? What were they?

We reported phase II results by my colleague, Roberto Pili in The Journal of Clinical Oncology which showed that in a group of 206 men tasquinimod improved progression free survival by about 17 weeks.

So what did you do in the phase III and what did you find?

We wanted to confirm that finding but also look at overall survival, trying to sort out the clinically meaningful benefit of progression free survival as a trait to overall survival. So 1,240 men participated, again randomised 2 to 1 to tasquinimod versus placebo.

And this is monotherapy?

This is monotherapy, so these patients received it continuously until they had radiographic progression or clinical symptom progression or death.

So could you give me the numbers on this, what came out?

We were positive for radiographic progression free survival, so it was 7 months for the tasquinimod group versus 4.4 months for the placebo group, however it did not translate into an overall survival advantage.

So you’ve got an efficacy signal, what is the meaning of this now, do you think, potentially for cancer doctors?

Because of the lack of benefit in overall survival, actually a slight trend in favour of placebo, so the concern is is this an agent that could move forward? Even though there is a signal in radiographic progression free survival the feeling was felt that it was not going to be moved forward. So we’re disappointed but there is still a lot of laboratory data suggesting that it could be used but right now the sponsors have decided to stop development in prostate cancer.

It is, of course, very important to establish negative findings sometimes. What is the take-home message for doctors coming out of this study?

Again, this is a novel single agent so can any one pathway have a difference in a disease? We certainly see a signal. The other thing, I think, is to regulatory agencies, because of so many agents now in metastatic castration resistant prostate cancer many folks feel that progression free survival should be a benchmark. However, here’s an example where it doesn’t translate to overall survival and that has to always call into question the results.

Thank you very much.