At least three generic versions of the popular osteoporosis treatment Fosamax are headed for pharmacy shelves with the expiration of the drug's main patent Wednesday, bringing patients hefty savings.
Two of the biggest makers of generic drugs, Teva Pharmaceutical Industries Ltd. and Barr Pharmaceuticals Inc., said Wednesday they would immediately begin selling generic Fosamax, which is made by Merck & Co.
Merck also is making a generic version of the drug, to be distributed by Corona-based Watson Pharmaceuticals Inc.
Fosamax was Merck's No. 3 drug last year, with sales totaling $3.05 billion.
Although it had long dominated the market for drugs that fight the bone-thinning disease, sales were down 3% from 2006 due to tougher competition.
Fosamax costs $80 to $85 per month.
Once drugs lose patent protection and generic competition starts, branded sales generally plunge by about two-thirds in just a few months. That's partly because HMOs and prescription plans quickly switch patients to the less-expensive generic drug, which can cost half as much.
When Merck released its fourth-quarter and year-end results a week ago, the company forecast Fosamax revenue would total just $1.1 billion to $1.4 billion this year.
Watson said it would sell the generic drug, under the chemical name alendronate sodium, in both 35 milligram and 70 milligram formulations taken once a week, starting late Wednesday.
Whitehouse Station, N.J.-based Merck will manufacture the tablets, and Watson will market and distribute them in the U.S., with Merck getting an undisclosed share of the profit.
Merck shares fell 24 cents to $45.71.