Genentech said Wednesday that it had been granted a fourth patent on its gamma interferon product, Actimmune. The patent is significant because it covers the process by which the drug is made.
Actimmune could become an important part of the South San Francisco-based company's lineup of drugs. It is expected to be the next Genentech product to receive approval by the Food and Drug Administration, initially for treatment of a rare inherited disorder that leaves children susceptible to infections.
Only about 250 children are known to suffer from that disorder, called chronic granulomatous disease. But the biotechnology company is also testing the genetically engineered drug in treating other conditions, including trauma-related infections and cancer, that have a much larger potential market.
Many biotech companies have been critical of the U.S. Patent Office's handling of process-patent applications, saying it has been nearly impossible in recent years to get such patents. Pending legislation, which Genentech helped draft, would loosen traditional standards under which process patents are granted.
Failure to yet obtain a process patent has created a major headache for another biotechnology company, and added to the controversy about such patents. In the long-running dispute between Amgen and Genetics Institute Inc. over the drug erythropoietin, or EPO, the U.S. International Trade Commission ruled that without a process (or final product) patent, Amgen was not protected against companies using its patented materials to manufacture EPO abroad for import to the United States.
Genentech's new patent will guard against such foreign-made imports, but its chief importance lies in how it fits in a total patent package. "Each patent is like a slat in a stockade," said David G. Webber, a biotech securities analyst with Alex. Brown & Sons in New York. "You need to have all of the slats in place, so there's no hole."
Previously, the company received patents covering its discoveries of the genetic materials of recombinant gamma interferon. In addition, the company said it has been advised by the patent office that a fifth patent will be issued soon.
The process patent, which Genentech said was awarded last week, covers the procedure from cell culture through product recovery for recombinant human gamma-interferon production in bacterial and mammalian host cells. Gamma interferon is one form of interferon--a protein that inhibits growth of viruses--produced in the human naturally, but in small quantities. Genetic engineering makes it possible to manufacture the substance in much larger amounts.
About $100 million worth of alpha interferon is being sold in the United States each year by biotech companies. Analysts say it is difficult to estimate the future market for gamma interferon because its potential is less well understood.
Genentech recently entered into cross-licensing agreements on patent rights with Biogen, which is developing gamma interferon for use in treating rheumatoid arthritis.