Hi panda, welcome and thanks for your question.  When patients don't respond to osteoporosis meds doctors usually check for some other cause other than age-related bone loss.  There are many medical conditions and medications that can cause bone loss.

Here's a link from the National Osteoporosis Foundation on medical disorders and medications that cause bone loss.  If you haven't been checked for any of these ask your Dr. about it and see if you can get an explanation or solution to this.  If you were to have a secondary disorder that causes bone loss it can be treated seperately and this can help to slow you bone loss down.

Since you were taking rocalcitrol I assume you had a vitamin D deficiency, has that been corrected and are your numbers up?  These therapeutic doses of D do take quite some time to elevate your scores so maybe you just haven't taken it long enough or something else is causing the bone loss.

Good luck and have you Dr. look into one of the secondary disorders or medications to see if this applies to you.