Fosamax, Actonel, Boniva: Why Might a Patient Be Prescribed One Oral Bisphosphonate Over Another?

Neil Gonter, MD Health Pro March 28, 2007
  • As you may be aware, there are currently 3 FDA approved therapies for osteoporosis.  I will try to give you the important differences in the drugs in order to allow you to make an educated decision on therapy.

     

    Long-Term Experience:

     

    The first drug approved was Fosamax, which was followed a few years later by Actonel and most recently by Boniva.  The long-term experience with these drugs is important, as we have always had the concern that they might stop working.  This can be by causing “frozen bone”, which may result in an increased risk of fractures.  However, this has not been seen yet.  In a New England Journal of Medicine study published in 2004, sustained improvement in bone density after 10 years of Fosamax was depicted.

     

    How they are taken:

     

    Fosamax and Actonel are weekly medications, while Boniva is monthly in oral form and every three months in intravenous (IV).  The technique for taking these oral drugs are similar.  One needs to take them first thing in the morning, while sitting or standing, without food for 30 minutes after Fosamax and Actonel and 1 hour after Boniva.  Taking a medication only once a month may sound appealing, however, this should not necessarily be the only factor that one should take into account when choosing a medication.  If on the other hand, one can not remember a weekly medication or can not tolerate any oral bisphosphonate, then monthly or IV Boniva, may be for them.

     

    Clinical Studies:     

     

    All three drugs show significant increases in bone density at vertebral as well as non-vertebral areas.  The graphs of the results of these drugs all seem similar, however, there are differences between them.

     

    In the only head-to-head trial, the FACT trial (Fosamax Actonel Comparison Trial), both medications showed significant increases in mineralization and reduction in markers of bone turnover (possible sign of decreased bone loss), with the changes with Fosamax greater than with Actonel.  However, this must be placed into context.  It should be clearly understood that these small differences might not really translate into what is really important: any decrease in fractures.  In the Boniva trial, it took 2 years to show any fracture decrease and in most of the Fosamax trials, it took at least as long to show a decrease in fractures, while Actonel was able to show fracture reduction in its first year.

     

    All three drugs have FDA approval for the treatment and prevention of post-menopausal osteoporosis.  Actonel has approval to reduce fractures at vertebral and nonvertebral sites (hip, wrist, pelvis, clavicle, leg, humorous), Fosamax at vertebral and hip, while Boniva has approval for the spine only.

     

    Conclusion:

     

    The choice of agents is a difficult question to answer due to the inability to compare the different agents across the different clinical trials.  Unless two drugs are studied head-to-head in a randomized, double-blind clinical trial, the comparison of one product to another is very limited.  There are many variables in the clinical trials that make direct comparisons of them problematic.  These differences include age of the study participants, difference in the baseline BMD at the different sites and the history of previous fractures.  All of these may affect the outcome of the trials.

  •  

    Disclaimer: The author is on the speaker’s bureau for P & G Pharmaceuticals as well as Roche/Glaxo Smith Kline, the makers of Actonel and Boniva, respectively.