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Commentary on Science, Innovation & New Products with a focus on Oncology & Hematology

Posts tagged ‘castrate resistant prostate cancer’

PREVAIL trial EAU 2015We’ve been following the updates on the PREVAIL study evaluating enzalutamide (Xtandi) versus placebo in metastatic castrate-resistant prostate cancer (CRPC) in the pre-chemotherapy setting for a while now. It’s interesting to see how the data evolves over time as it becomes more mature.

The first presentation, back in January 2014 at ASCO GU by Dr Tom Beer (OHSU) reported on the first 540 deaths and was subsequently followed by an update of the survival data at AUA in May of the same year by Dr Chris Evans (UCLA).

This morning at the European Urology Association (EAU) in Madrid in the late breaking session on prostate cancer, the honour fell to Professor Bertrand Tombal (Leuven), who did a very nice job of reviewing the mature PREVAIL data (based on 765 deaths) and providing some context for how the CRPC landscape is being impacted by AR pathway inhibitors.

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We have been following the results of the checkpoint inhibitors for several years now, first with ipilimumab (Yervoy) and lately with anti-PD1 and PD-L1 inhibitors such as nivolumab, pembrolizumab and MPDL3280A. Irrespective of the antibody used, the best results we’ve seen have in melanoma, lung and bladder, but some tumour types such as colon and prostate cancers have barely been responsive at all.

Why is that?

Can we find ways to make non-responsive solid tumours responsive to immune therapies, and if so, what strategies could we employ to enable improved responses and outcomes?

At the ASCO Genitourinary (GU) meeting in Orlando this weekend there were some interesting hints of what might be possible in the not too distant future.

To learn more about this phenomenon, we conducted an interview with a leading cancer immunologist to find out what they are doing to make a difference in the GU space.

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It’s now time to turn our attention to genitourinary oncology and, in particular, prostate, renal and urothelial bladder cancers. This week brings this ASCO GU meeting (#GU15), which is being held in Orlando this year and began this morning.

There are quite a few interesting topics being covered here, particularly in the poster sessions over the next three days. Hopefully, 2015 will also bring more good news in this space as 2014 was a rather dismal one on several fronts!

We decided to highlight some of the most interesting abstracts on castrate resistant prostate cancer and urothelial bladder cancer in our latest conference preview.

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Medivation-LogoThere’s nothing better than seeing good news in the early morning email alerts I have set up on cancer research!

 

astellas-logo-no-sloganToday, it was the turn of Astellas and Medivation to announce the results of the TERRAIN study, which is a primarily European phase 2 trial that began in March 2011 in the prechemotherapy setting for castrate resistant prostate cancer (CRPC). The trial met its primary endpoint of progression free survival (PFS).

 

Why is this an important landmark in CRPC and what does the initial data show?

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Over the last few years we have seen new therapies emerge for the treatment of advanced prostate cancer from immunotherapy to chemotherapy and second generation hormone therapies. Each of these has increased survival and outcomes. Along the way though, a host of other agents have fallen by the wayside with a raft of negative phase III trials that did not live up to their phase II promise. These include atrensentan, dasatinib, ipilimumab, lenalidomide and more recently, custirsen.

Much of the focus has, however, been on the hormonal drugs, abiraterone (Zytiga) and enzalutamide (Xtandi) in both the pre and post chemotherapy settings. One thing has become clear though – over time the responses attentuate as resistance sets in. This is very common with oral therapies.

Some big questions to consider here are:

  • What causes it?
  • How can we overcome adaptive resistance?
  • Would combination approaches produce synergistic results?
  • Or should we consider new targets with a different mechanism of action (MOA)?

The answers to these questions are now being eagerly explored through basic, translational and clinical research. I was very impressed with the quality of research and breadth of fresh ideas and approaches emerging from the SBUR, SUO and UOR sessions at AUA this year, including new combination trials already in the planning phase.

In the past, Bertrand Tombal (Belgium) talked about the Grand Cru year for clinical research in CRPC. In the future we may well look back at 2014 as a similar Grand Cru year for basic research for prostate cancer, if the findings translate to clinic. The bench-to-bedside process is very much alive and well in urologic research.

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This week we turn our focus to the American Society of Clinical Oncology Genitourinary (ASCO GU) symposium being held in San Francisco.

The hottest topic is highly likely to be the Medivation and Astellas data for enzalutamide (Xtandi) in the pre-chemotherapy setting in men with advanced prostate cancer who are asymptomatic or slightly symptomatic and naive to chemotherapy.  Previously, I wrote in detail about the Medivation announcement regarding the interim analysis where the PREVAIL trial was found to meet its primary endpoint (open access).

Dr Tom Beer, OHSU

Dr Tom Beer, OHSU

The company subsequently stated that the data had been accepted as a late breaker for the the ASCO Genitourinary meeting in San Francisco this weekend.  That data is being presented on Thursday morning in the oral prostate cancer session by Dr Tomasz Beer (OHSU), who is the Deputy Director of the Knight Cancer Institute and a prostate cancer specialist.

The ASCO GU 2014 abstracts will be available for perusing as of 5pm ET today.

This week I caught up with Dr Beer to discuss not only the details relating to the PREVAIL data, but also how enzalutamide (Xtandi) potentially fits in the advanced prostate cancer competitive landscape given that he also participated in the abiraterone (Zytiga) COU-AA-302 trial in the same clinical setting.

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TBMS Sprycel Logohe results of the phase 3 clinical trial of dasatinib (Sprycel) plus docetaxel/prednisone versus placebo and docetaxel/prednisone in men with castration-resistant metastatic prostate cancer (CRPC) are expected soon.

BMS recently updated the clinicaltrials.gov website to show that the dasatinib phase 3 randomized prostate cancer “READY” trial (NCT00744497) of 1500 men completed data collection in August.

Data is expected before year end and, If positive, could be a late breaker at the ASCO Genitourinary Cancers Symposiusm (ASCO GU) in Orlando from Feb 14-16, 2013.

Dasatinib inhibits Src-family kinases (SFK)

Dasatinib is approved for Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia and Ph+ acute lymphoblastic leukemia (ALL). It is a BCR/ABL, LYN and Src family tyrosine kinase inhibitor.

Src-family kinases (SFK) are involved with tumor proliferation and bone metabolism.

In the phase 1 & 2 clinical trials of dasatinib with docetaxel, many of the men with prostate cancer saw a decrease in PSA from baseline, reduction in tumor size and bone scan improvement and stabilization. Encouraging early results led to the start of a phase 3 randomized trial of dasatinib in combination with the chemotherapy, docetaxel.

However, the results for Src inhibitors in prostate cancer have been mixed to date, with not all agents generating positive data. Astra-Zeneca’s saracatinib (AZD0530), for example, showed little clinical effect on its own in a phase 2 prostate clinical trial.

It has been suggested by KOLs at numerous conferences that Src inhibitors may potentially be more effective in combination with other cancer agents. Data suggests that Src might be a resistance mechanism to enzalutamide (MDV3100), so it would be interesting to see whether a dasatinib/enzalutamide combination may be more effective than enzalutamide on its own.

Meanwhile, we await the data to see whether the combination of dasatinib with docetaxel generates a significant increase in overall survival over docetaxel alone. While some are “hopeful”, Dr Oliver Sartor, Professor of Cancer Research at Tulane Medical School noted in a prostate cancer session at ESMO 2012 that, “the docetaxel-combination graveyard is big!

Update Jan 26 2013: Dasatinib Phase 3 Data at ASCO GU

Results from the dasatinib phase 3 prostate cancer trial are a late breaking abstract at the 2013 ASCO Genitourinary Cancer Symposium (ASCO GU) in Orlando. The data will be presented on February 14 by John Araujo MD PhD, Assistant Professor in the Department of Genitourinary Medical Oncology at The University of Texas MD Anderson Cancer Center in Houston.

LBA #8: Overall survival (OS) and safety of dasatinib/docetaxel versus docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC): Results from the phase III READY trial.

With the collapse of the Dendreon share price today following poor sales data (Adam Feuerstein on The Street has an excellent write up about this), attention has again focused on the prostate cancer market.

Zytiga (abiraterone acetate) was recently approved by the European Medicines Agency (EMA), following FDA approval earlier this year.

The EMA Committee for Medicinal Products for Human Use granted the marketing authorization for Zytiga at it’s July 2011 meeting.  The approval noted,

“The poor prognosis of the target patient population represents a high unmet medical need while the novel mechanism of action of abiraterone has the potential to offer an alternative therapeutic option for these patients.”

What does this mean for sales of sanofi-aventis’ cabazitaxel (Jevtana), which was approved in Europe earlier this year?

Given that both drugs have approval in the same indication for metastatic castrate resistant prostate cancer (mCRPC) post-docetaxel chemotherapy, and the price is likely to be comparable, my guess would be that Jevtana sales will take a big hit.

After a sick prostate cancer patient has undertaken several cycles of chemotherapy with docetaxel, why would they not want to take an oral pill as opposed to another chemotherapy drug, which does have a less than stellar adverse-event profile.  The answer is they will probably take a chemo-holiday and use Zytiga.

Jevtana simply came to the market too late in Europe, and Zytiga gained accelerated approval.  It’s a reminder that we live in a dynamic pharmaceutical market place, as the news last night from Dendreon has also reminded us.

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.

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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.

ResearchBlogging.orgSartor, 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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