Biotech Strategy Blog

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

Posts tagged ‘PIVOT trial data’

PIVOT-prostate-cancer-intervention-versus-observation-trial-dataTimothy J. Wilt MD, MPH presented an update on the VA, NCI, AHRQ Prostate cancer Intervention Versus Observation Trial (PIVOT) on the final day of the 2012 European Association of Urology (EAU) Congress in Paris.

I previously wrote on this blog about the PIVOT data presented by Professor Wilt in the plenary session at the 2011 American Urological Association Annual meeting.

The PIVOT trial objective according to Dr Wilt, was to answer the following question:

Among men with clinically localized prostate cancer detected during the early PSA era, does the intent to treat with radical prostectomy reduce all-cause & prostate cancer mortality compared to observation?

PIVOT enrolled 731 men from 1994 to 2002 who were randomized to either receive radical prostatectomy or undergo just observation.

The results from the trial provide level 1 evidence based medicine (highest standard) concerning the survival benefits conferred by radical prostactectomy (with the potential for quality of life impacts such as incontinence & erectile dysfunction), as compared to not undertaking surgery, but instead doing observation only in the form of watchful waiting or active monitoring.

Dr Wilt told the urologists in the EAU 2012 Congress plenary session, that after a median follow-up of 10 years (interquartile range = 7.3 to 12.6), the median survival was 12.7 years. Wilt told the audience that:

“Prostate cancer mortality was uncommon occurring in only 7.1% of men, it did not vary considerably by patient age, race, comorbidities or health status, but did vary considerably by tumor risk status ranging from 3 % in men with low risk disease to 13 % in men with high risk disease.”

PIVOT Prostate Cancer Mortality Results

No of Deaths: 52/731 (7.1%)

    • Low risk  (3.4%)
    • High risk (8.4%)
    • High risk (13.3%)

In the men who had death judged to be due to prostate cancer, absolute differences between treatments were less than 1%,” Wilt said.

As far as I could determine, the data presented at EAU 2012 was no different from the PIVOT data presented at AUA 2011 other than being another year mature.

A subgroup analysis showed that surgery conferred no survival benefit over watchful waiting except for high-risk patients.  In his EAU 2012 presentation, Dr Wilt described the subgroup findings in more detail (emphasis added):

Low Risk Prostate Cancer

“In men with low risk prostate cancer, disease mortality occurred in less than 3% and did not differ between radical prostatectomy and observation”  (HR=1.48; ARR=1.4, P=0.54). This favored observation.”

High Risk Prostate Cancer

“Among men with high risk tumors, prostate cancer mortality occurred in approximately 13%. Radical prostatectomy produced a 60% relative risk reduction  (HR = 0.4, ARR = 8.4) of borderline significance (P=0.04).

Intermediate Risk Prostate Cancer

“Among men with intermediate risk prostate cancer, we found a non-significant reduction of 4.6%.”

PSA <= 10ng/ml

“In men with PSA <= 10ng/ml there was no significant difference between radical prostatectomy and watchful waiting.” (HR = 0.92, ARR=0.3%, P=0.82).  The findings were virtually identical throughout the course of the study. The lines are essentially superimposable for prostate cancer mortality in men treated with observation or with radical prostatectomy.”

PSA > 10ng/ml

“Among men with baseline PSA > 10ng/ml, radical prostatectomy reduced prostate cancer death by a relative 64% and an absolute difference of 7.2%. You can see the curves begin to separate at approximately 7 years.” (HR=0.36, ARR= 7.2%, P=0.03)

PIVOT-Prostatectomy-versus-observation-data-conclusion-2012Dr Wilt’s conclusion based on the latest study data was that:

“In men with localized prostate cancer detected during the early PSA era, radical prostatectomy compared to observation did not significantly reduce all-cause and prostate cancer mortality. Absolute differences through at least 12 years were less than 3%” 

These results are important findings that should impact the treatment of men diagnosed with early stage, low risk prostate cancer.

The fact that the survival curves do not diverge except for high-risk patients presenting with a PSA > 10ng/mL, may also have an impact on the ongoing PSA prostate screening debate.

If the PIVOT data results in more men being put on watchful waiting/active monitoring, then it should lower the overtreatment that screening currently produces.  Urologists will, however, need to be prepared to counsel their patients accordingly and forego the economic benefits that undertaking surgery affords many of them.

Urologists at the EAU in Paris greeted the PIVOT trial data in silence and an absence of social media interaction (I did not see any urologists tweet enthusiastically about it).

Many urologists who have trained many years to perform complex surgical techniques may find the idea of watchful waiting an anathema.

Adopting a policy of watchful waiting in many prostate cancer patients may also place economic pressures placed on those urologists who need a throughput of patients to recover or amortize the cost of expensive technology such as the da Vinci robotic system.

The PIVOT trial data is, however, level 1 evidence based medicine that cannot be ignored.

Hopefully, this analysis of the PIVOT trial data will be published in a peer-reviewed journal in the not too distant future so that it can reach a wider audience than those urologists who attended the AUA 2011 and EAU 2012 plenary sessions.

Update July 18, 2012

The results of the PIVOT trial presented at AUA 2011 and EAU 2012 have been published in the New England Journal of Medicine (online first, July 18, 2012).

NEJM PIVOT prostate cancer

A survey of patients who had their prostate removed showed there was no significant difference in complication rates between open retropubic radical prostatectomy (ORRP) and robotic assisted laparoscopic surgery (RALRP).

This is an important finding because 85% of prostatectomies in the United States are undertaken using robotic-assisted techniques, yet there has been little published data to show that this technique improves functional outcomes.

At the European Association of Urology (EAU) annual congress last year in Vienna some of the challenges and opportunies with robotic surgery were raised:

  • lack of data on improved functional outcome
  • need for licensing of robotic surgeons
  • high learning curve – it takes 250 patients to become proficient

In reality, we see hospitals marketing their robotic surgery to patients in shopping malls and with advertisements on the side of buses.  You can read Gary Schwitzer’s thoughts on some of the recent marketing claims & “gizmo idolatry.”

This is why a survey comparing the results of open to robotic assisted prostate removal surgery is important evidence based medicine. Published online first in the Journal of Clinical Oncology, Barry and colleagues randomly surveyed 800 men who filed Medicare claims between August and December 2008.  685 completed surveys were returned, and information on adverse events was obtained.

The data highlights the dramatic effect on quality of life that prostate cancer surgery can have, irrespective of the surgical technique. The men rated themselves:

31.1% – moderate or big problem with continence  (95% CI 27.5 to 34.8%)

88.0% – moderate or big problem with sexual function (95% CI 85.4% to 90.6%)

Breaking this down by technique (robotic surgery versus open prostatectomy):

Continence: 27.1% of men (Open) versus 33.3% (Robotic) – not significant (P=0.113)

Sexual Function: 89.0% of men (Open) versus 87.5% (Robotic) – not significant (P=0.57)

The authors conclude in their JCO paper:

Our results do not demonstrate a lower risk of problems with incontinence or sexual function after RALRP compared with ORRP.

In fact, after adjusting for potential confounders, there was at least a strong trend toward a higher risk of patient-reported moderate or big problems with incontinence following RALRP.

The authors in their discussion do raise the interesting question as to whether patients were led to believe that they would have fewer side effects with robotic surgery, which may have impacted the survey findings.  This merits further investigation.

There is clearly a need for patients to give informed consent, and be aware of the risks and complications of prostate cancer surgery, particularly with regards fundamental quality of life issues such as continence or sexual function.

The accompanying JCO editorial by Matthew Cooperberg and colleagues from UCSF is well worth reading and raises the question as to whether men with prostate cancer should expect better outcomes than those reported in the survey?

What the survey by Barry et al did not do is look at the volume of procedures and experience level of the surgeon, both of which are associated with outcomes.

Cooperberg noted that “surgeons performing fewer than 5 prostatectomies per year account for approximately half the national volume.

A chilling statistic, and if you factor in the learning curve of more than 200 procedures to be competent at robotic surgery, it is perhaps not surprising that some men experience higher complication rates than others.

Which brings me back to the importance of the PIVOT (Prostate Cancer Intervention versus Observation Trial) data presented in the plenary session at the 2011 annual meeting of the American Urological Association (AUA) in May last year.

Why has this practice changing data not been published in a peer-reviewed journal yet?

The fact that the updated PIVOT study results presented at AUA 2011 have not been published (to the best of my knowledge) is a disservice not only to the medical and scientific community, but to men with prostate cancer whose treatment should be guided by evidence-based medicine.

The long-term results of the PIVOT trial presented by Professor Wilt showed no benefit of radical prostatectomy over watchful waiting, except for high-risk patients.  Yet, the reality is that many men end up having surgery. This may be considered overtreatment and an exposure of more men than is necessary to the complications of prostatectomy, irrespective of whether this is robotic or open surgery.

The decision to undergo radical prostatectomy should be an informed one, not only as to the risks and benefits of the surgical technique, but also whether the surgery should be performed in the first place as compared to “watchful waiting.”

I hope the paper and editorial published in the JCO this month will generate some debate. Next month I will be at the European Urology Association annual congress in Paris.

References

ResearchBlogging.orgBarry, M., Gallagher, P., Skinner, J., & Fowler, F. (2012). Adverse Effects of Robotic-Assisted Laparoscopic Versus Open Retropubic Radical Prostatectomy Among a Nationwide Random Sample of Medicare-Age Men Journal of Clinical Oncology DOI: 10.1200/JCO.2011.36.8621

Cooperberg, M., Odisho, A., & Carroll, P. (2012). Outcomes for Radical Prostatectomy: Is It the Singer, the Song, or Both? Journal of Clinical Oncology DOI: 10.1200/JCO.2011.38.9593

Update August 12, 2012 – Paper published in European Urology shows lower incontinence and greater rate of erection recovery with robot-assisted radical prostatectomy

A paper published online (July 20, 2012) in the journal, European Urology by Franceso Porpiglia provides some evidence that robot-assisted radical prostatectomy offers functional benefits to patients. I have not read the full paper only the freely available abstract.

The clinical trial evaluated the functional outcomes of 120 men in a randomized clinical trial where half (n=60) received radical prostatectomy (RARP) that was robot-assisted and the other half (n=60) who had the operation laparoscopically without robot assistance (LRP).

Following the surgery performed by Dr Porpiglia, the functional outcomes between the two groups were compared. Those men operated on with robot assistance showed:

  • Lower incontinence. “Continence after 3 mo was 80% in the RARP group and 61.6% in the LRP group (p = 0.044), and after 1 yr, the continence rate was 95.0% and 83.3%, respectively (p = 0.042)”
  • Better erection recovery. “Among preoperative potent patients treated with nerve-sparing techniques, the rate of erection recovery was 80.0% and 54.2%, respectively (p = 0.020).”

The challenge of this study is that although it was randomized, it reflects the results of only one surgeon with a small number of patients.

Dr Matthew Cooperberg (@cooperberg_ucsf) was quoted by Reuters saying that this was likely the best study we were going to get showing the benefits of RARP over LRP. On twitter he said the real question was now between radical prostatectomy and external radiation therapy (XRT).

https://twitter.com/cooperberg_ucsf/status/233427660708126721

Biotech Strategy Blog is 1 today!  I can’t believe that a year has gone by so quickly!  Before moving on to year 2, I thought a brief review might be interesting.

What have been the top posts on Biotech Strategy Blog this past year?

In terms of total visitors per post:

  1. Results from NEJM Lucentis v Avastin AMD CATT clinical trial
  2. AUA Results from PIVOT study show no benefit from radical prostatectomy in low risk early stage patients
  3. ASCO 2011 Cabozantinib (XL184) may be an exciting new prostate cancer drug
  4. Merck’s capthepsin-K inhibitor odanacatib in osteoporosis
  5. Update from AACR on new prostate cancer drugs to watch

For those who like metrics:

  • Highest number of reads per month was in May (19,927)
  • Year to date there have been 79,179 visitors
  • Most visited day was September 22, 2011 (2136 reads)

What have been some of the other posts that I enjoyed writing about?

My top 5 (not in rank order) would be:

  1. Alpharadin will be new treatment option for prostate cancer
  2. Patient advocacy session at European Hematology Assocation EHA Congress shows impact of drug adherence on outcome
  3. How nanotechnology may revolutionize the detection of traumatic brain injury using a sensor that changes color
  4. Innovation in Nanotechnology will lead to improved drug delivery, diagnostics & imaging
  5. Insights of the decade

Finally, I have produced 4 videos that you can watch on the biotechstrategy channel on YouTube.


It’s been a busy but enjoyable year. Biotech Strategy Blog is still a work in progress.  If you have enjoyed a particular series of posts or would like me explore a topic or theme in the future, do email me or post a comment.

The recent announcement from the United States Preventative Services Task Force (USPSTF) on prostate cancer screening has stimulated a lot of debate.  “Dr Len’s Cancer Blog” from the American Cancer Society has a thoughtful piece about the “to screen or not to screen” dilemma. It is reminiscent of the breast cancer mammography debate.

Scott Hensley’s post on “Shots”, the NPR health blog also provides a good overview of the debate and issues. I confess I was surprised by the vehemence of the response from some practising urologists on twitter such as Dr Benjamin J. Davies (@daviesbj), Assistant Professor of Urology at the University of Pittsburgh School of Medicine:

What do the US Preventative Task Force authors say? In the findings published in the October 7, 2011 issue of the Annals of Internal Medicine, the conclusion from their peer-review of the literature is that:

“screening based on PSA identifies additional prostate cancers, but most trials found no statistically significant effect on prostate cancer–specific mortality.”

This is nothing new – the evidence in favor of Prostate-Specific Antigen (PSA) screening for prostate cancer has for sometime been inconclusive at best. Research published in the British Medical Journal earlier this year suggested that indiscriminate screening for prostate cancer may not be of value until we obtain more sensitive biomarkers.

All the USPSTF have done is a retrospective literature review that confirms our current state of knowledge.

Despite the amount of $$$ that have been spent on PSA clinical studies, no convincing data in support of it as a screening tool for all men has been developed. That’s not to say that it has no utility or benefit.

If PSA screening does detect some prostate cancers and early treatment may save lives particularly in those with an aggressive form of the disease, then it’s hard not ask:

  • What is the alternative if PSA screening is now discouraged?
  • Will this mean more men will not be screened, even those at high risk, with a consequent increase in prostate cancer mortality or lower overall survival?
  • Will insurers refuse to cover PSA testing moving forwards?
  • Will family physicians actively discourage PSA testing?

One limitation of the USPSTF report that struck me while reading through the analysis and recommendations, was the absence of data from the Prostate Cancer Intervention versus Observation (PIVOT) trial that was presented in the plenary session at the American Urological Association (AUA) annual meeting earlier this year.

I wrote in a previous blog post about the PIVOT data presented at AUA 2011 by Dr Wilt. This VA/NCI/AHRQ randomized clinical trial showed in a 12 year follow-up of over 5000 men with localized prostate cancer, no benefit from radical prostatectomy in low risk early stage patients.

In my opinion it is practice changing data that sadly has not yet been published in a peer-reviewed journal which is why it was not included in the USPSTF analysis. A few photographs that I took at the presentation of the PIVOT data are shown below:

The 12 year survival data showed that in those patients with PSA <=10 ng/ml there was no significant difference in survival over observation versus RP.

However in those patients with PSA > 10ng/ml there was a significant difference in mortality (p=0.03 HR=0.36) suggesting that in the small sub-group of patients with high PSA, RP did provide a benefit over “watchful waiting.” PSA measurements may therefore help in the treatment and ongoing management of patients.

If one of the challenges of PSA screening is the issue of the harms from treatment, then the PIVOT data that showed no difference in mortality through watchful waiting over radical prostatectomy (RP) except for high risk patients is important.

Roger Chou and his colleagues in their Annals paper did note this:

“When available, results from the Prostate Cancer Intervention Versus Observation Trial, which compared prostatectomy with watchful waiting for screening-detected cancer, may help clarify which patients would benefit from prostatectomy or other active treatments, potentially reducing harms from unnecessary treatment.”

The issue may, therefore, not be one that PSA screening per-se is the problem, but that in too many men, a raised PSA results in unnecessary surgery or overtreatment with its consequent risks and harms.

As reported by Alemozaffar and colleagues in the September 21, 2011 issue of the Journal of the American Medical Association (JAMA), 2 years after RP only 35% of men could maintain a functional erection.

“At 2 years after treatment, erectile dysfunction was reported by 619 of 987 (63% [95% CI, 60%-66%]) men (334/511 [65% {95% CI, 61%- 69%}] in the prostatectomy group”

That’s depressing news when coupled with other side-effects from RP or other interventions such as incontinence or problems with bowel function.

It adds further support to the idea that the potential risks versus benefits from prostate cancer surgery and deciding who should actually have surgery or other intervention, is where there’s also a need for more debate.

Men need to be able to make an informed decision. Some urologists may not be unbiased in their treatment recommendations given they have a vested interest in earning money from surgery or maintaining utilization rates of expensive robotics. Data from the PIVOT trial, when published, is evidence-based medicine that will impact their practice.

Use of prostate cancer risk calculators to assess those patients at high risk who might benefit from RP or other intervention could also help lower the harms that currently impact the utility of PSA screening.

How will men approach the PSA screening debate? Despite the USPSTF recommendations I will still be asking my physician for an annual PSA test, so long as it remains covered by my health insurance. The PSA test and digital rectal exam remain the main ways we have to detect prostate cancer early.

Psychologically I value the risk of picking up a disease early higher than the downside of a false positive. I would, however, not rush into any surgery or radiotherapy absent a clear finding that the benefits of intervention outweighed the potential harm.

My approach towards prostate cancer PSA screening again reminds me of the debate over mammography.  We all want to discover cancer early, and have the best possible treatment options as a result.

Hopefully, as our understanding of the biology of prostate cancers and associated biomarkers develop we may be able to generate new screening tests that have fewer false positives than PSA and provide for more accurate early diagnosis.

ResearchBlogging.orgAlemozaffar, M., Regan, M., Cooperberg, M., Wei, J., Michalski, J., Sandler, H., Hembroff, L., Sadetsky, N., Saigal, C., Litwin, M., Klein, E., Kibel, A., Hamstra, D., Pisters, L., Kuban, D., Kaplan, I., Wood, D., Ciezki, J., Dunn, R., Carroll, P., & Sanda, M. (2011). Prediction of Erectile Function Following Treatment for Prostate Cancer JAMA: The Journal of the American Medical Association, 306 (11), 1205-1214 DOI: 10.1001/jama.2011.1333

Roger Chou, MD, Jennifer M. Croswell, MD, MPH, Tracy Dana, MLS, Christina Bougatsos, BS, Ian Blazina, MPH, Rongwei Fu, PhD, Ken Gleitsmann, MD, MPH, Helen C. Koenig, MD, MPH, Clarence Lam, MD, MPH, Ashley Maltz, MD, MPH, J. Bruin Rugge, MD, MPH, & Kenneth Lin, MD (2011). Screening for Prostate Cancer: A Review of the Evidence for the U.S. Preventive Services Task Force Annals of Internal Medicine, E-375 (October 7)

Launch of Zytiga (abiraterone acetate) at 2011 annual meeting of American Urological Association (AUA) in Washington DCThe market for prostate cancer therapies is set to expand from $1 billion currently to $5 billion by 2015, according to analysts reported by this morning’s Washington Post/Bloomberg news.  This is perhaps no surprise given the recent approval of abiraterone acetate (Zytiga®) from Ortho Biotech (JNJ).

New clinical data on prostate cancer clinical trial results is expected at the 2011 annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago this weekend from many of the prostate cancer therapies in development such as MDV3100, TAK700, ARN-509, cabozantinib (XL184), ipilimumab, custirsen (OGX-11), BPX-101, alpharadin, denosumab (Xgeva®) and Prostvac-VF.

Indeed, one could argue that prostate cancer is becoming a competitive marketplace.  Any emerging biotechnology company that is not already developing a prostate cancer drug is likely to find it a hard market in which to create a blockbuster.  By the time any drug comes to market, there will be incumbents with effective products who have captured market share.

Prostate cancer is an exciting market to watch from a marketing strategy and patient perspective, as several companies potentially bring new products to market over the next few years.

However, the bottom line is that patients will live longer as a result of all the innovation that is taking place.  Not only that but physician education and awareness of how to treat this disease is also likely to improve as they seek out knowledge on new therapies and treatments.  This to many will make a major difference.  At the recent American Urological Association (AUA) annual meeting, the sessions on treatment of prostate cancer were standing room only.  There is clearly a demand for knowledge out there as the treatment paradigms change.

At the other end of the spectrum, there is also innovation taking place in terms of improved diagnosis and treatment of prostate cancer.  Whether we should screen all men for PSA remains a controversial topic, although use of risk calculators do appear to offer less false positives.  Indeed, calculating risk is going to be one of the key areas that primary care physicians and urologists need to focus on, particularly in the light of the PIVOT trial data that was presented at AUA, showing radical prostatectomy (with risks including incontinence and erectile dysfunction) was not better than watchful waiting in low-risk, early stage disease.

However, a presentation I am looking forward to at ASCO 2011 is on circulating tumor cells (CTC) and whether these can be a prognostic or even a predictive biomarker.   Both the phase III MDV3100 and abiraterone acetate clinical trials captured CTC data.  It will be exciting news at ASCO 2011 if circulating tumor cells that require only a blood sample offer an improvement over PSA not only for detection of prostate cancer, but in monitoring the disease over time.

I will be at ASCO 2011 this weekend, and look forward to writing more on prostate cancer from the conference!

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