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Merck facing lawsuits concerning its best-selling osteoporosis medication Fosamax
Plaintiffs cite a link between bisphosphonates and a rare disease that causes jawbone degeneration.
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Amid more than 10,000 lawsuits over the painkiller Vioxx, Merck & Co. is facing even more legal fire, this time related to its osteoporosis drug Fosamax. Plaintiffs allege that long-term Fosamax use causes osteonecrosis of the jaw, a rare type of jawbone degeneration.
Bisphosphonates, which are linked to osteonecrosis of the jaw (ONJ), include Fosamax (alendronate sodium), Zometa (zoledronic acid) and Aredia (pamidronate disodium). Novartis makes Aredia and Zometa and is also a target of litigation.
In April, a Florida law firm filed a class-action suit alleging that Merck sold and aggressively marketed Fosamax despite the ONJ risk. A Knoxville, Tenn., law firm filed four similar suits involving 60 plaintiffs last fall, according to Daily News Central, a health care news Web site.
The plaintiffs contend that Merck and Novartis did not give sufficient warning of the ONJ risk. They are seeking damages and want to force the defendants to give dental examinations to those being prescribed the three drugs.
Oral surgeons have contended that long-term use of osteoporosis drugs like Fosamax may cause ONJ, Daily News Central reported.
The FDA approved Fosamax in February 1998. Fosamax entered the market in 2001 and reportedly generated $3.2 billion in sales in 2005.
Merck statement
“Most reported cases of bisphosphonate-associated osteonecrosis have been in cancer patients treated with intravenous bisphosphonates, but some have occurred in patients with postmenopausal osteoporosis,” according to a Merck news release. “Known risk factors for osteonecrosis include a diagnosis of cancer, concomitant therapies (chemotherapy, radiotherapy, corticosteroids), poor oral hygiene and comorbid disorders (pre-existing dental disease, anemia, coagulopathy, infection).”
Clinical trials and 10 years’ data involving more than 17,000 patients showed no reports of ONJ among patients taking Fosamax, Merck noted in the release. The company has received postmarketing reports showing ONJ in patients taking Fosamax. However, “postmarketing reports do not necessarily indicate causality,” it asserted.
The FDA asked Merck to change the Fosamax label to reflect the ONJ risk. Merck complied, submitting a draft of a revised label to the FDA in March 2005.
Merck received the FDA’s comments concerning the label in June and made the new label available in July, according to the release.
Fosamax is indicated for osteoporosis in postmenopausal women and men diagnosed with osteoporosis. The new Fosamax label warns patients who develop ONJ while taking bisphosphonates to visit an oral surgeon.
Stuart Hirsch, MD, editor of the Health Policy, Patient and Practice Issues section of the Orthopedics Today Editorial Board, confirmed Merck’s statement about ONJ occurring mainly in patients receiving intravenous bisphosphonates. However, he noted other risk factors include diabetes and immune system suppression related to cancer chemotherapy.
“The primary incidence of osteonecrosis of the jaw as associated with patients taking bisphosphonates has been almost entirely, but not 100%, in those patients receiving intravenous bisphosphonates,” Hirsch said. “There are only two primary bisphosphonates that are used intravenously. One of them is pamidronate and the other is zoledronate. Those receiving Fosamax or the other oral bisphosphonates have been in the distinct minority.”
He added that further discussion with a patient's prescribing physician is appropriate.
Dr. Hirsch does not have a financial interest in Merck & Co. or its products.
For more information:
- FDA clinical and safety information about Fosamax. Available at fda.gov/cder/foi/label/2005/020560s038_021575s007lbl.pdf.
- Osteoporosis drugs blamed for jaw rotting disease. Daily News Central. April 15, 2006. Available at health.dailynewscentral.com/content/view/2209.
- Statement by Merck & Co., Inc. Regarding FOSAMA (alendronate sodium) and Rare Cases of Osteonecrosis of the Jaw. Available at merck.com.