Hansenpharm Co. began selling generic versions of Lilly's blockbuster antipsychotic Zyprexa (olanzapine) in China this month after winning a groundbreaking lawsuit against Lilly late last year.
The court battle lasted five years and marked the first time that a Chinese company won a patent case against a major multinational pharmaceutical company. While the case was in litigation, Hansenpharm, based in Lianyungang in Jiangsu province, was prohibited from producing or selling its version of the drug.
Lilly received a Chinese patent for Zyprexa in 2001, covering all production methods. In 2004, Hansenpharm sued to amend and narrow the patent so that it would cover only the specific manufacturing method used by Lilly. In December 2006, the Shanghai Supreme Court found that Hansenpharm had established how to produce olanzapine without violating Lilly's patent. Lilly also had an earlier patent, dating back to 1995, covering the manufacture of a constituent chemical.
"These two patents are both method patents, not production patents or usage patents," said Cheng Yuehua, a patent lawyer at Guangdong's Scihead & Partners law firm, which was not involved in the lawsuit.
"Hansenpharm developed a new method to create olanzapine, so Hansenpharm doesn't infringe upon existing patents," he told PharmAsia News. "That's why they won the lawsuit. For Chinese pharmaceutical companies, Hansenpharm has set a precedent by breaking through the patent barrier set up by the giants in the industry, which will encourage others to try the same approach."
When contacted by PharmAsia News, Lilly declined to comment. A Hansenpharm manager, who declined to give his name, would say only that the company had no plans to export olanzapine overseas.
Zyprexa had global sales of $4.4 billion in 2006. In the U.S., the drug has patent protection until 2011 ("The Pink Sheet" DAILY, April 14, 2005).
In China, Zyprexa is sold for 788 yuan (US $103) for 28 pills - twice that of Hansenpharm's olanzapine, which retails for 399 yuan (US $52.50).
"Compared to the Lilly product, Hansenpharm has a great advantage on the price, while as a medicine, it has the same effect," a researcher in Shanghai's Institute of Pharmaceutical Industry told PharmaAsia News. The institute helped Hansenpharm to develop the new method to synthesize olanzapine.
However, Hansenpharm may not enjoy for long the full benefits of a price advantage.
Chinese patent regulations do not allow for patent extensions, and Lilly's standard six-year patent term would have expired this year. In the near future, other Chinese companies are expected to start manufacturing olanzapine as well.
According to Cheng, multinational pharmaceutical companies generally try to apply for patents as soon as possible, but trials and other development work often eat up much of the six-year Chinese patent window.
"On the other hand," Cheng told PharmAsia News, "if they apply later, they might lose the patent altogether. They must time their patent applications carefully."
In June 2006, another multinational, Pfizer, saw its patent for Viagra upheld by the Beijing High People's Court in a trial pitting the U.S. drug giant against 12 Chinese pharmaceutical companies. The decision overturned a 2004 ruling by China's patent review board, which had invalidated the sildenafil patent due to "insufficient disclosure" of the invention, according to official state media.
-Dai Jialing
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