Ivax got setback in extended release Metformin tablets

Depomed has today announced that Judge Charles Breyer of the United States District Court for the Northern District of California has granted Depomed's motion for summary judgment of infringement of US6340475 and US6635280 in the company's patent litigation against IVAX Corporation, and denied all three of IVAX's summary judgment motions.
The impact of the court's rulings is that IVAX's infringement of Depomed's patents has been established as a matter of law, without the need for a trial on that issue. The court ruled against IVAX on IVAX's motions for summary judgment related to the validity and enforceability of the patents, and the lack of willful infringement on the part of IVAX.

The court also rejected an interpretation of a disputed patent term proposed by IVAX in support of its invalidity arguments, and instead affirmed Depomed's interpretation of the disputed patent term.
The court has not yet set a trial date for the case.
In January 2006, Depomed sued IVAX for infringement of US6,340,475 and US6,635,280 by IVAX's extended release metformin hydrochloride tablets. The patents are held by Depomed and are related to the company's AcuForm drug delivery system.

Patent in dispute

US6340475

Claim 1 covers a controlled-release oral drug dosage form for releasing a drug whose solubility in water is greater than one part by weight of said drug in ten parts by weight of water, said dosage form comprising a solid polymeric matrix with said drug dispersed therein at a weight ratio of drug to polymer of from about 15:85 to about 80:20, said polymeric matrix being one that swells upon imbibition of water thereby attaining a size large enough to promote retention in the stomach during said fed mode, that releases said drug into gastric fluid by the dissolution and diffusion of said drug out of said matrix by said gastric fluid, that upon immersion in gastric fluid retains at least about 40% of said drug one hour after such immersion and releases substantially all of said drug within about eight hours after such immersion, and that remains substantially intact until all of said drug is released.

US6635280

Claim 1 covers acontrolled-release oral drug dosage form for releasing a drug whose solubility in water is greater than one part by weight of said drug in ten parts by weight of water, said dosage form comprising one or more polymers forming a solid polymeric matrix with said drug incorporated therein at a weight ratio of drug to polymer of from 15:85 to 80:20, said dosage form being one that when swollen in a dimensionally unrestricted manner as a result of imbibition of water is of a size exceeding the pyloric diameter in the fed mode to promote retention in the stomach during said fed mode, that releases said drug into gastric fluid by the dissolution and diffusion of said drug out of said matrix by said gastric fluid, that upon immersion in gastric fluid retains at least about 40% of said drug one hour after such immersion and releases substantially all of said drug after such immersion, and that remains substantially intact until substantially all of said drug is released.