JUro Research on Xiaflex

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coive

 
Here I offer my summary and critique of a major investigation on the efficacy of Xiaflex for the treatment of  Peyronies Disease, reported by Martin Gelbard and others in The Journal of Urology, July 2013. Reported were  reduction in penile curvature and change in bother score on a questionnaire following experimental treatment with Xiaflex. My summary/critique focuses on  Xiaflex and penile curvature.    

The report's investigation found approximately 8 degrees greater average reduction for Xiaflex treatment than for control/placebo treatment (17 degrees vs 9 degrees). This is a finding  that would certainly be welcomed by Auxilium (the manufacturer  of Xiaflex), but I can't see how the  report offers much of practical value in the everyday work of doctors. Too much information is left out of the report.  And there are other problems, including its questionable analysis of the data .

The report describes two international experiments and then combines their results in an unnecessary meta-analysis. The investigation began with 832 subjects but lost 220 of them over the course of the two studies, ending up with 612 subjects. There is no attempt to account for such a large loss of subjects in this sort of investigation, leaving the reader to guess possible reasons. Information on age and race was collected but nothing was reported on what, if anything, was done with this information. Information on direction of curve was collected but nothing was reported on what, if anything, was done with this information.  For each study, the subjects were stratified into two groups, moderate curvature (30-60 degrees) and severe curvature (61-90 degrees), but the report says nothing about what was done with this differentiation either in treatment or data analysis. Subjects were randomly assigned either to a Xiaflex treatment group or a placebo/control group, with twice as many assigned to the Xiaflex group. Subjects were administered Xiaflex or placebo injections for as many as four six-week cycles, but the report does not say how many subjects received all treatment cycles--how many received one cycle...or two...or three...or all four. Treatment cycles were stopped  if subjects reached zero degrees curvature or if there were other reasons (not specified) for stopping them.  Therapies mentioned in the report included injections of either Xiaflex or placebo plus subjects doing molding on their own three times a day between cycles. No other therapies were mentioned, so the reader is left to infer that there were none (I doubt that there were none). If the experiments were in fact conducted in double-blind fashion, as claimed, it is hard to see how placebo subjects were not recognized as such given typical bruising and swelling associated with Xiaflex injections, unless placebo injections induced these reactions as well. The report does not say. As already mentioned, data on severity of curvature were not reported in the results

Although the investigation as reported in this 2013 J Urology article falls short in many ways, it does offer needed evidence regarding the efficacy of a drug for treating Peyronies Disease. At a minimum it served its purpose of showing whether Xiaflex has any effect at all in the treatment of Peyronies Disease. It showed that it does. But the magnitude of its effect was not really shown in this report. A different kind of analysis of the data would be needed in order to weigh the relative contribution of Xiaflex against other variables in the experiment. Another investigation using this different kind of analysis might weigh the relative contribution of Xiaflex as well as that of other therapies (such as ultrasound shock wave, carbon dioxide injections, Verapamil injections, Trental injections, testosterone implantation, traction per time used, etc.) in the reduction of penile curvature.

Seems to me a working doctor would need a table of the individual raw data in order to make practical sense of the investigation.  Without the raw data, a doctor is left with what little can be made of the results given in the report on the two Xiaflex groups. The obvious generality is evident: Effectiveness of treatment varies. For some patients, Xiaflex injections may not be effective at all (without adjutant therapies) . But for some they may be completely effective. This research did show an average of 17 degrees reduction for Xiaflex subjects, a mean reduction of 1.2 standard deviation (a sizeable reduction, even compared to the placebo group's 9 degree, or .6 standard deviation, reduction!). The report was not clear as to how many Xiaflex cycles were needed in order to reduce curvature to zero degrees, which some subjects did reach.

I am left to conclude from the report that, in general, Xiaflex has limited value in the treatment of Peyronies Disease. Keeping in mind its limited value in the treatment of Peyronies Disease, doctors who  use Xiaflex in treating Peyronies Disease should  include it as one part of a more comprehensive approach.


james1947

Coive

QuoteHere I offer my Here I offer my summary and critique of a major investigation on the efficacy of Xiaflex on the efficacy of Xiaflex....
Can you give us some information regarding your qualification to make "Here I offer my summary and critique of...."?

James
Age 71, Peyronies from Jan 2009 following penis fracture during sex. Severe ED.
Lost 2" length and a lot of girth. Late start, still VED, Cialis & Pentox helped. Prostate surgery 2014.
Got amazing support on the forum

NeoV

I appreciate the critique, and I would not be surprised at all if it was indeed hardly effective. I'll have to read the report myself.

Jonbinspain

I discussed Xiaflex at some length with Dr Kuehhas, who also is qualified to administer this drug.

His opinion was that yes, it can and does work, but but not in all cases. And, there are no guarantees with Xiaflex. Plus maximum curve improvement in my case would have been 30%. Not enough.

I recall writing directly to the manufacturer about this, some while ago. As I had calcified plaque,  I enquired if it could work for me. The reply I got was that they really didn't know because calcified plaque had not been part of their tests.

I would guess for obvious reasons!...

LWillisjr

I've had similar conversations with Dr. Levine. Xiaflex is in no way a miracle drug. At best someone could see "some improvement". But i have posted before that someone with a severe curve is likely to end up with surgery as VED/Traction/Xiaflex is not going to cure someone with and extreme curve. Xiaflex does seem to have some documented success that it is slightly better than Varapamil and is why it is the suggested treatment of choice currently.
Developed peyronies 2007 - 70 degree dorsal curve
Traction/MEDs/Injections/Surgery 2008 16 years Peyronies free now
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