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AUA 2011 European men with a biochemical recurrence have a lower prostate cancer survival compared to the United States

One of the sessions that I attended at the 2011 annual meeting of the American Urological Association (AUA) focused on research into advanced prostate cancer. A particularly thought provoking presentation was:

Time trends of biochemical recurrence (BCR) following radical prostatectomy (RP) among 1574 BCR patients (Abstract #639)

Presented by Alex Haese from Hamburg, Germany, this paper was a retrospective analysis of 1,574 patients who had a biochemical recurrence (PSA > 0.2 mg/dl) following RP. Researchers looked at clinical progression and cancer specific survival rates and compared their findings to published United States data.

The results appeared to be somewhat depressing for European patients who experience a BCR, with a time to BCR of 1.8 years, compared to 2.1 years in the US research by Pound from Johns Hopkins and 2.4 years in the data published by Hull, at Memorial Sloan Kettering Cancer Center (MSKCC).

Once a BCR is experienced, the time to metastases is faster in Europe, 4.7 years in the research presented by Haese at AUA, as compared to 8 years in US research by Pound. Risk factors for metastasis free survival include time to BCR i.e.

“The longer the interval between RP and BCR, the greater the probability of being met-free.”

In other words delaying time to progression is associated with longer survival.

Following BCR, time to Prostate Cancer death was 6.0 years in the 1,574 European patients, compared to 13 years in the US Pound research. Again, the data presented showed that,

“The longer the interval between RP and BCR, the greater the probability of being alive.”

This research must be put into context, as metastasis and death in BCR patients are rare (92% of the 1,574 patients with BCR were free of metastases at 5 years, 81% at 10 years). However, for those patients who did progress, the results appear significantly different between the US and Europe.

What could explain this?

The presentation left this question unanswered, although in Q&A it was briefly touched upon. One person raised the question of whether differences in screening could be the difference in Europe vs. US?

Other questions that come to mind are whether the subject populations in the Hull and Pound data were comparable. The German data also had more patients (1574) compared to 304 in the Pound research and 147 (Hull) raising the question that the larger sample size may be more accurate data?

Other factors that might possibly explain the difference include:

Androgen deprivation therapy (ADT)
Radiotherapy
Supportive care (eg bisphosphonates)

All of which tend to be more aggressively pursued as treatment options in the USA.

Overall, this presentation raised the interesting question of US/European differences in Prostate Cancer progression that hopefully will be answered by future research.

AUA 2011 New Prostate Cancer products in development beyond the androgen axis

There is a lot of focus at the annual meeting of the American Urological Association (AUA) here in Washington DC on metastatic castrate resistant Prostate Cancer (mCRPC), and the recently FDA approved adrenal steroid inhibitor, abiraterone acetate (Zytiga®).

Drugs in development that target the androgen receptor, such as MDV3100, are also generating a lot of interest from urologists.

However, Oliver Sartor (Tulane) in the Saturday morning satellite symposia that I attended, focused on emerging therapies in CRPC, beyond the androgen axis. His hypothesis:

“Cancers are devious and some of the mechanisms of AR activation appear to be ligand-independent and resistant to all current androgen-axis targeted therapies.”

What this means is that focusing on adrenal steroid inhibition or blocking the androgen receptor may not be sufficient to prevent disease progression. If we are looking for a Prostate Cancer cure, then will it take multiple drugs, including those that target various stromal sites? That is the intriguing question that Sartor raised.

Indeed, if there is one take home from this meeting, it is that the “desert” of prostate cancer therapies has now blossomed into a multiplicity of potential new therapies and development, which will mean that urologists and oncologists will soon be spoilt for choice as abiraterone and MDV3100 are not the end of the story.

Sartor highlighted some interesting ones on the horizon to watch out for:

Alpharadin: This is a bone targeted therapy that uses radioactive Radium 223 to kill cancer cells. It is being developed by Norwegian company, Algeta in partnership with Bayer Schering Pharma AG. The 900 patient phase III trial completed accrual earlier this year in Jan 2011. Phase II data was published in the Lancet in 2007 by Nilsson et al. Data from alpharadin will be “coming soon” according to Sartor.

XL-184 (cabozantinib): Activated MET is highly expressed in prostate bone metastases. Exelixis XL-184 is a small molecule tyrosine kinase inhibitor that specifically inhibits both MET and VEGFR2.

Data from a phase 2 study of XL-184 in castrate resistance patients was presented last year at the EORTC-AACR-NCI Symposium on Molecular Targets and Cancer Therapeutics in Berlin by David Smith et al (Abstract 406).

Both XL-184 and alpharadin would be potential competitors to Amgen’s denosumab (Xgeva®).

Other new products in development “Beyond the Androgen Axis” that Dr. Sartor mentioned included Prostvac-VF, BPX-101 and ipilimumab. A phase III trial of ipilimumab, both pre- and post- docetaxel is now underway in mCRPC. A phase III trial of Prostvac-VF will start later this year with 1200 patients in a placebo controlled study with minimally symptomatic, castration-resistant metastatic prostate cancer patients.

Over the next few years a lot of data may emerge on exciting new treatment options. Coupled with the basic research that is going on, tremendous progress in the treatment of Prostate Cancer is already taking place.

According to Sartor “multiple drugs will be necessary to cure mCRPC and that is our greatest challenge today.” Major progress is now being made towards this.

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American Urological Association Annual Meeting 2011 Satellite Symposia

By Pieter Droppert on May 12, 2011

I am off to Washington DC tomorrow for the annual meeting of the American Urological Association (AUA).

If you are not able to attend, then you can follow the Twitter coverage on Pharma Strategy Blog where Sally Church (@MaverickNY) will be aggregating the tweets. The conference hashtag is #AUA2011. I also expect to be live-tweeting from the conference.

Like many medical conferences in the United States, the AUA meeting kicks off with independent continuing medical education (CME) satellite symposia on topics of interest.

As a lawyer who has to pay for his own continuing legal education (CLE) credits, I have to confess that I am somewhat cynical that other professionals such as physicians expect to have their CME paid for through free industry-sponsored events. These symposia are certainly not cheap to run.

However, compared with Europe, CME events in the United States are usually well-produced and fair balanced, albeit with a topical theme that obviously relates to the sponsor’s interest.

The two satellite symposia that I will be attending at AUA are Friday evening’s Amgen supported “Managing Skeletal-Related Events in Patients with Prostate Cancer” and the Saturday morning Astellas/Medivation supported “Reason for Hope: Key Advances in the Management of Castration-Resistant Prostate Cancer.”

While at Quintiles, I was lead CRA/European Project Manager for the phase III trial trial of risedronate in elderly women at risk of hip fracture, so I am interested in bone related treatments, and am looking forward to hearing more about denosumab (Xgeva®) and its impact on skeletal related events (SRE).

Oliver Sartor (Tulane) raises some excellent questions in a recent paper published in the Asian Journal of Andrology, “if a patient has a SRE, does it affect the way a patient feels, functions or survives?”

Sartor argues that a better definition of the benefit a drug has on SRE’s would be “a reduction in pain, analgesic consumption or improvement in quality of life (QoL)” instead of the current “feel, function or survive” standard.

He notes that patients with bone-metastatic castrate resistant prostate cancer (CRPC) have a limited life expectancy, so that QoL is a key issue. “An asymptomatic event linked to a future adverse event is less meaningful in a patient with metastatic CRPC.”

Sartor concluded his paper by saying:

“The lack of effect of bisphosphonates or denosumab on patient-reported outcomes including QoL, pain or analgesic consumption continues to be a disappointment for this entire field.”

When we talk about a reduction in SRE’s what does this really mean for the patient? I look forward to hearing what the expert panel at Friday evening’s symposia on this topic and hope it will be addressed.

Moving on to the other satellite symposium, supported by Medivation/Astellas, that I will be attending early on Saturday morning. I expect this symposium will focus on new drugs in the pipeline such as MDV3011 and ARN-509 that target the androgen receptor. Hopefully they will also discuss other therapeutics, such as the recently approved abiraterone acetate (Zytiga®), as well TAK-700, which has a similar mechanism of action to abiraterone, i.e. they both inhibit CYP17 and testosterone production.

I’m looking forward to hearing what the expert panel has to say about the need to take prednisone with abiraterone, and whether there are any issues surrounding long-term usage if abiraterone ends up being used earlier in the pre-chemotherapy setting. Updated data from the COU-AA-301 trial will be presented at AUA on Monday, and I expect a lot of interest from urologists in this.

The satellite symposia are set to be a good warm up act to the start of the main AUA meeting that runs from May 14 to 19 in Washington DC. I’ll be writing more from the AUA 2011 over the next few days.

Sartor, O. (2011). Denosumab in bone-metastatic prostate cancer: known effects on skeletal-related events but unknown effects on quality of life Asian Journal of Andrology DOI: 10.1038/aja.2011.33

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Posts tagged ‘AUA’

AUA 2011 European men with a biochemical recurrence have a lower prostate cancer survival compared to the United States

AUA 2011 New Prostate Cancer products in development beyond the androgen axis