Goliath US pharmaceutical producer Pfizer filed an accusation Tuesday in Beijing against a July decision by the China State Intellectual Property Office (SIPO) to overturn the firm's patent for its erectile dysfunction drug Viagra.

Sources with the Beijing No 1 Intermediate People's Court Tuesday confirmed they received the complaint from Pfizer. But the court has not yet decided whether to place the case on file for trial.

According to Chinese law, the decision will be made by court within seven work days after receiving the plaintiff's accusation.

Sources with the intermediate court predicted the decision will be made after the National Day holidays, a seven-day period.

"Pfizer has a strong legal basis for the appeal and is confident about the outcome," a statement issued by the US company Tuesday said.

Currently, Pfizer's patent on Viagra remains valid and enforceable, pending the final decision by the final appellate court. As such, Pfizer remains the only approved and legitimate manufacturer of Sildenafil (the active pharmaceutical ingredient of Viagra) in China, the statement said.

Pfizer acquired the patent rights on Sildenafil in 2001 from the SIPO. The drug can correct erectile dysfunction problems in many men, including those with prostate or cardiovascular disease. Later in the year, a dozen domestic pharmaceutical companies requested the SIPO cancel Pfizer's patent rights.

SIPO's Patent Re-examination Committee in July this year overturned the firm's 2001 patent because it does not conform with Article 26 of China's Patent Law.

(China Daily September 29, 2004)