Xiaflex is an injected treatment designed to soften and break down existing scar tissue, through its ability to destroy collagen. The result of this process (a series of injections) can be a reduction in curvature. It is thought that combining Xiaflex with traction may be useful in maximising its effectiveness.
In a related condition Dupuytren's Contracture, Xiaflex has been very effective as this study clearly shows:
Unfortunately though peyronie's disease and dupuytren's contracture do have some similarities, there is also an important difference. With Dupuytrens the scar tissue is attached to the underlying tissue, and this attachement can be loosened and then broken with the use of Xiaflex (and other surgeical options). In peyronie's disease there is no such attachment and as such there is not such a simplistic solution. The hope with peyronie's is that the tissue itself changes in composition and regains some of its former qualities (elastisity etc).
The current clinical trial results for Auxilium's Xiaflex are located here: http://www.auxilium.com/ProductPipeline/PeyroniesDisease.aspx
As you can see, it has been somewhat successful in reducing curvature but the results are not exactly mindblowing. It's worth taking into account though that more results will be available in future, and the process will be fine tuned somewhat. It's feasible that for some men, the use of Xiaflex could potentially be the difference between needing surgery and not, so I believe that it has its place in the treatment of peyronie's disease.
Auxillium do not plan on seeking FDA approval for Xiaflex for peyronie's disease until at least 2011.