Once-a-Year Drug to Treat Osteoporosis

The new once-yearly Aclasta manufactured by Novartis has been shown to be as effective as weekly Fosamax in reducing incidence of bone fracture in women with postmenopausal osteoporosis (PMO). One in two women with PMO will suffer an osteoporotic fracture, if untreated. Reportedly, patients treated with Aclasta had a 70 % risk reduction in new spine fractures and a 40 % risk reduction in hip fractures (compared to placebo). Both Fosamax and Aclasta belong to a medication class called bisphosphonates.

Aclasta (zoledronic acid) is actually not a new drug -- is has been used in the U.S. under the name Zometa for treatment of hypercalcemia in malignancy and osteolytic bone metastasis. It will be sold in the U.S. under the name Reclasta. Why do we need a new name for the same drug? It is probably for marketing purposes so that patients do not confuse Zometa (used in malignancy) with Reclasta.

Currently, Fosamax is the most prescribed osteoporosis drug with worldwide sales of $3 billion in 2005 (its patent will expire in 2008).

Boniva by Roche has the advantage of once-a-month dosing and it rapidly gained market share at the expense of Fosamax.

A few questions come to mind:

Why do we need once-a-year drug for osteoporosis? We already have effective medications for this condition...

Oral bisphosphonates are cumbersome to take which leads to low-compliance -- 60% of patients taking weekly bisphosphonates (Fosamax) stop treatment within a year.

Patients must take the drug on an empty stomach in the morning, stay upright and wait for 30 minutes before eating, drinking or taking any other medication.

A medication that needs to be taken only once per year may help alleviate the compliance problems.

Once-a-year treatment sounds great but what is the drawback?

Aclasta can only be given as IV infusion. There is no oral form of the medication (no pill). It also has a different safety profile (different side effects) than oral bisphosphonates.

Bottom line

Compared to IV infusion, the once-a-month Boniva should be OK in terms of compliance -- it is only 12 pills per year after all.

Novartis: Once a year drug helps bones. CNN Money.
Study Shows New Once-a-Year Osteoporosis Shot Reduces Fractures. WSJ.com
Bisphosphonates. Susan Ott, Department of Medicine, University of Washington.
The World Health Organization has an online Fracture Risk Assessment Tool.
Links to medications by Epocrates, Inc.
Images source: Wikipedia, public domain.


  1. In addition to Fosamax and Boniva, there is another promising drug candidate being manufactured by AMGEN. It's called Denosumab and had been shown in pre-clinical and clinical trials to be much more effective than Fosamax. It is administered subcutaneously, twice yearly, and targets a completely different mechanism. It works through the RANK ligand system as is thought to be more specific than the chemical drugs. It'll be interesting to see which drug stays on top.

  2. Does Denosumab have the problem of bone necrosis in jaws that some of these medications present?