Although more drugs to treat rare diseases have been broughtto market since the inception of the Orphan Drug Act in 1983,most of those drugs still show below-average returns oninvestment for the drug makers.

According to an article published Wednesday in the Journal ofthe American Medical Association, "about 83 percent of thePharmaceutical Manufacturers Association-sponsored orphandrugs had a lower-than-average return on investment, whiledevelopment costs were greater than average."

Two blockbuster orphan drugs -- recombinant human growthhormone to treat growth failure and recombinanterythropoietin to treat chronic renal failure -- have had annualsales of more than $100 million.

The Act and its amendments provide manufacturers withexclusive marketing rights for seven years for drugs designedto treat diseases that affect 200,000 or fewer people in theUnited States.

Companies sponsored 34 marketed and 24 experimentalorphan drugs in the 17 years prior to the Act, wrote thearticle's author, Carolyn Asbury, of the Robert Wood JohnsonFoundation in Princeton, N.J. Since the Act took effect in 1983,she wrote, companies have sponsored 39 orphan products thathave come to market.

(c) 1997 American Health Consultants. All rights reserved.