Menarini’s Priligy (Dapoxetine HCl) Use Patent held Not Valid as being Obvious

Menarini launched Priligy in Korea. Dapoxetine HCl is the active ingredient in Priligy tablets. Korean patent No. 719, 977 covers the branded products and is listed in Green List of KFDA. The patented invention is “Methods of Using Rapid-Onset Selective Serotonin Reuptake Inhibitors for Treating Sexual Dysfunction.” The patent at issue is not for a compound invention but for the second use invention. The Korean patent for the second use invention will expire on June 5, 2021. Several Korean generic companies filed invalidity proceedings to challenge the second use patent. Menarini will face generic companies’ challenges soon.

On August 23, 2013, the IPT of KIPO held that the patent in issue is not valid because the compound and its use have been disclosed in the prior art. There has been no challenge to the compound patent so far. The key issue for the second use patent was a new limitation of “on as as-needed basis” in claim language. The patentee argued that such a new limitation was not found in the prior art and made the claimed use invention being novel and nonobvious over the prior art. However, the IPT rejected the argument on the ground that such limitation is related to a method of administering a drug and thus such limitation may not be regarded as an element for a patent claim under Korean patent law.

The patentee appealed the IPT decision to the Patent Court and the case is pending.