I have never heard of this.  Why not call the company that
makes it and ask if it's appropriate for someone without bone
mets?

My guess is that they will say no.  When an investigational drug
is approved for clinical trials, it is only approved for specific
applications and may not be used for purposes that the FDA
has not approved.  This sounds like it could be a bad thing, but
it's really a good thing in most cases and protects people against
possibly severe side effects and possible loss of opportunity to
try other treatments, in order to get some unproven benefit.
The fact that the drug lowers PSA in some patients who have
bone mets doesn't at all prove that it will lower PSA in patients
without bone mets.  It might very well be that the drug only attacks
prostate tumor cells that reside in bones.

Your current doctor is probably right in not being willing to use it,
even assuming he can legally do so.

My advice is, don't focus on one therapy and then chase after
a doctor who will give it to you.  There are a lot of conventional
therapies, and a lot of investigational ones.  Do some research
on all of them.

Look for example at the National Cancer Institute's website on
clinical trials (http://cancer.gov) and at (http://clinicaltrials.gov).

Best of luck.

   Alan