Japanese Warned on Biotech Patent

Genentech, the U.S. biotechnology firm, has warned seven Japanese companies to stop developing one of its drugs in what analysts describe as the start of the first biotechnology patent battle in Japan.

Genentech’s Tokyo lawyer said the company had sent letters to the pharmaceutical firms claiming priority over mass-production genetic engineering technology for the drug, tissue plasminogen activator.

Analysts estimate that the drug, an anti-thrombosis agent that may prove effective against heart attacks, will have a potential worth of $350 million a year in the market in the Japanese market.

The seven Japanese firms, including Asahi Chemical Industry and Mitsui Toatsu Chemicals, have tissue plasminogen activator technologies at various stages of development and testing.

The lawyer said Genentech, which is based in South San Francisco, had filed for a patent in Japan. The letter was required to protect the pending patent.

Genentech’s Japanese licensees Kyowa Hakko Kogyo and Mitsubishi Chemical Industries, started clinical testing of tissue plasminogen activator in Japan last December.

Genentech received a British patent on Feb. 26.

Tissue plasminogen activator is a biological agent that occurs naturally in small amounts and seems to be able to dissolve the plaque that clogs blood vessels and contributes to heart attacks.