Pfizer bolsters lawsuit against Sun to block generic Lyrica (pregabalin)

Pfizer adds violation of a second patent on Lyrica in its case against Sun

Pfizer, which is currently suing Sun Pharma on a patent infringement of its pain drug Lyrica (pregabalin), has bolstered its case against the Indian generic maker by adding alleged violation of a second Lyrica patent.

On May 3, 2009, Pfizer Inc. and Northwestern University filed a lawsuit in the U.S. District Court for the District of Delaware on May 3, 2009, alleging that Sun infringed Pfizer’s and Northwestern’s rights in U.S. Patent No. 6,197,819 through filing of an abbreviated new drug application (ANDA) to make and market a generic version of Lyrica (pregabalin).

The ‘819 patent is owned by Northwestern and exclusively licensed to Pfizer’s subsidiary, Warner Lambert Co. LLC.

This week, Pfizer amended the lawsuit by adding a second patent. The new claims on Sun Pharma has violated U.S. Patent No. 5,563,175 as well while seeking approval for its generic version of Lyrica (pregabalin).

Patent No ‘175 is jointly owned by Northwestern and Warner-Lambert.

Pfizer said the company has received a letter from Sun Pharma informing that Sun’s ANDA contained a Paragraph IV certification that the ‘175 patent was invalid, unenforceable, and not infringed by Sun’s proposed product.

Sun had sent a response letter to Pfizer six weeks ago with similar claims on patent ‘819 arguing that its para IV filing for pregabalin strengths 25, 50, 75, 100, 150, 200, 225, 300mg that ‘819 patent is invalid, unenforceable and will not be infringed by the commercial manufacture use, or sale of the generic product.

The amended complaint seeks judgments of infringement for both patents-in-suit and injunctive relief that would bar Sun from marketing and manufacturing generic versions of Lyrica (pregabalin) prior to patent expiration.

The lawsuit also seeks monetary relief if Sun were to sell its generic product, and fees and costs.

…Lupin, Wockhardt already under fire

This lawsuit is the latest to be filed in Pfizer’s and Northwestern’s efforts to prevent generic makers from making generic versions of Lyrica (pregabalin).

The two partners currently have lawsuits pending against Indian pharma generic players Wockhardt Ltd and Lupin Ltd besides Sun.

Sun and Wockhardt have breached one patent each while Lupin three, of its valid patents on Lyrica (pregabalin), alleges Pfizer.

While Pfizer has accused Lupin for the alleged infringing of its valid patents Nos. ‘819, ‘876 and ‘175, the world’s largest drug maker, accused Sun and Wockhardt for violating patent no.’819 which cover Lyrica (pregabalin) in US, in their filing  to US FDA seeking para IV certification for generic versions.

Pfizer’s disputed patent no.6,197,819 (’819) refers Gamma Amino Butyric Acid Analogs and Optical Isomers for the treatment of fibromyalgia,” issued March 6, 2001. Patent no.6,001,876 (’876) refers to Isobutylgaba and Its Derivatives for the Treatment of Pain,” issued December 14, 1999 and No.5,563,175 (’175) GABA and L-glutamic Acid Analogs for Antiseizure Treatment,” issued October 8, 1996.

Some of these patents are expected to expire by March 6, 2018 .

Teva, Sandoz, Actavis, Cobalt Laboratories, Alphapharm Pty Ltd are the other generic companies being sued by Pfizer on Lyrica patent violations in US.

Lyrica (pregabalin) is an oral pill that is chemically related to the other gabapentin grugs like Neurontin and Gabarone. It is used for treating pain caused by neurologic diseases such as postherpetic neuralgia as well as seizures.

The mechanism of action of pregabalin is unknown. Pregabalin binds to calcium channels on nerves and may modify the release of neurotransmitters (chemicals that nerves use to communicate with each other). Reducing communication between nerves may contribute to pregabalin’s effect on pain and seizures. The FDA approved pregabalin in December 2004.

The US FDA approved pregabalin in December 2004. for use in treating epilepsy, diabetic neuropathy pain and post-herpetic neuralgia. Pfizer started selling it on the US market in fall 2005.

In June 2007 the FDA approved Lyrica as a treatment for fibromyalgia. Fibromyalgia is a disorder classified by the presence of chronic widespread pain and a heightened and painful response to gentle touch. Fibromyalgia also include debilitating fatigue, sleep disturbance, and joint stiffness.

Global sales of Lyrica is estimated to be around 1.2 billion. Lyrica sales jumped 45% last year to $675 million, majorly offsetting Pfizer’s losses from dropping revenues from its leading block-buster drug Lipitor. Analyst estimates that Lyric could continue to be blockbuster that can spin more earnings for Pfizer in the coming years as well.

Founded in 1849, Pfizer is the world’s largest company in terms of drug sales. Pfizer makes the number-one selling drug Lipitor (atorvastatin, used to lower blood cholesterol); the neuropathic pain/fibromyalgia drug Lyrica (pregabalin); the oral antifungal medication Diflucan (fluconazole), the long-acting antibiotic Zithromax (azithromycin), the well-known erectile dysfunction drug Viagra (sildenafil citrate), and the anti inflammatory Celebrex (celecoxib) (also known as Celebra in some countries outside USA and Canada, mainly in South America).

Pfizer agreed to buy pharmaceutical giant Wyeth for US$68 billion, on January 26, 2009. Pfizer cloaked an annual revenue of $48.418 billion (2007).