Schering-Plough and Hoffmann-LaRoche, drug giants that each own patent rights to a genetically engineered protein, agreed Thursday that each may sell the product without fear of being sued by the other for patent infringement.
The protein, called alpha interferon, occurs naturally in human beings and stimulates the body's immune system against certain types of cancers and viruses.
Schering-Plough has licensed patent rights from Biogen, a leading biotechnology company that has developed a version of the protein at its headquarters in Cambridge, Mass.
In early March, Hoffmann-La Roche received a U.S. patent based on its version of the substance.
Hoffmann-LaRoche said at that time that it believed the patent award would prevent Schering-Plough from selling alpha interferon.
In April, however, Schering-Plough began marketing the protein in Ireland and has said it hopes to have approval from the Food and Drug Administration soon to begin selling the protein in the United States by year-end.