Introduction
The litigation between Pfizer Inc. and Mylan Laboratories Limited is a significant example of patent disputes in the pharmaceutical industry. This article will delve into the key aspects of the cases, focusing on the drug products, patents in suit, and the legal arguments presented.
Case Overview: Pfizer Inc. v. Mylan Pharms. Inc. (Toviaz®)
Drug Product and Patents-in-Suit
In the case of Pfizer Inc. v. Mylan Pharms. Inc., the drug product in question is Toviaz® (fesoterodine fumarate extended-release tablets), which is approved for the treatment of overactive bladder symptoms such as urinary incontinence, urgency, and frequency[1].
Nature of the Case
Mylan filed an Abbreviated New Drug Application (ANDA) with the FDA seeking approval to market a generic version of Toviaz®. Pfizer subsequently sued Mylan for patent infringement, asserting claims under U.S. Patents Nos. 6,858,650, 7,384,980, 7,855,230, 7,985,772, and 8,338,478. Mylan stipulated to infringement but challenged the validity of the patents on the grounds of obviousness[1].
Court Findings
The court found that Mylan failed to demonstrate that a person of ordinary skill in the art (POSA) would have selected 5-hydroxymethyl tolterodine (5-HMT) as a lead compound or that modifying 5-HMT to create fesoterodine would have been obvious. The court highlighted several flaws in Mylan’s approach, including the limited consideration of prior art and the unpredictable nature of prodrug development. The court also determined that the salt formation process for fesoterodine was highly unpredictable, further supporting the non-obviousness of the patents[1].
Case Overview: Pfizer Inc. v. Mylan Pharms. Inc. (Sutent®)
Drug Product and Patents-in-Suit
In another significant case, Pfizer Inc. v. Mylan Pharms. Inc., the drug product at issue is Sutent® (sunitinib malate), which is indicated for the treatment of various cancers, including advanced renal cell carcinoma and gastrointestinal stromal tumors[2].
Nature of the Case
Mylan filed an ANDA seeking approval for a generic version of Sutent®, stipulating that its products would infringe Pfizer’s patents. The primary issue at trial was whether the asserted claims of U.S. Patents Nos. 6,573,293 and 7,125,905 were invalid as obvious. Mylan argued that a POSA could have derived sunitinib from prior-art compounds, but the court disagreed[2].
Court Findings
The court rejected Mylan’s arguments, finding that the process of modifying prior-art compounds to arrive at sunitinib malate would have required significant guesswork and variation of parameters. The court also dismissed Mylan’s proposed lead compounds, such as SU5416 and SU5408, due to their significant shortcomings and lack of relevant data. Additionally, the court found that Mylan’s reliance on a hypothetical compound, dimethyl sunitinib, was not persuasive, as it had never been synthesized or tested[2].
Case Overview: Pfizer Inc. v. Mylan Laboratories, Inc. (Amlodipine Besylate)
Drug Product and Patents-in-Suit
In Pfizer, Inc. v. Mylan Laboratories, Inc., the dispute centered around amlodipine besylate tablets, a generic version of Pfizer’s Norvasc®. Mylan filed an ANDA seeking approval for 2.5 mg, 5 mg, and 10 mg dosage strengths of amlodipine besylate tablets, which Pfizer alleged infringed U.S. Patents Nos. 4,572,909 and 4,879,303[4].
Nature of the Case
The trial focused on the validity of the 303 patent, as Mylan argued that it was invalid as obvious under 35 U.S.C. § 103. However, the court found that Mylan failed to prove by clear and convincing evidence that the303 patent was invalid or unenforceable due to inequitable conduct before the PTO[4].
Court Findings
The court upheld the validity of the `303 patent, rejecting Mylan’s arguments that the claimed compounds were obvious. The court emphasized that Mylan did not establish a prima facie case of obviousness and that Pfizer’s evidence of objective indicia of non-obviousness supported the patent’s validity[4].
Settlement and Generic Competition: Detrol LA®
Settlement Agreement
In a separate case involving Detrol LA® (tolterodine tartrate extended-release capsules), Pfizer settled its litigation with Mylan, allowing generic competition to commence no earlier than January 1, 2014, and no later than March 1, 2014. This settlement did not alter Pfizer’s financial guidance for 2012[5].
Key Takeaways
- Patent Validity: In all cases, Pfizer successfully defended the validity of its patents against Mylan’s challenges of obviousness.
- POSA Analysis: The courts consistently found that Mylan failed to demonstrate that a POSA would have been motivated to create the claimed compounds or that the modifications necessary to arrive at those compounds would have been obvious.
- Prior Art and Lead Compounds: The courts emphasized the importance of thorough prior art analysis and the selection of appropriate lead compounds, highlighting Mylan’s shortcomings in these areas.
- Unpredictability in Drug Development: The cases underscore the unpredictable nature of drug development, particularly in the creation of prodrugs and salt forms, which supported the non-obviousness of Pfizer’s patents.
- Settlements and Generic Competition: Settlements can delay generic competition, as seen in the Detrol LA® case, but ultimately allow for generic entry into the market.
FAQs
What was the main issue in the Pfizer Inc. v. Mylan Pharms. Inc. case involving Toviaz®?
The main issue was whether Mylan’s generic version of Toviaz® infringed Pfizer’s patents and whether those patents were invalid as obvious.
Why did the court find Pfizer’s patents for Sutent® non-obvious?
The court found that the process of modifying prior-art compounds to arrive at sunitinib malate required significant guesswork and that Mylan’s proposed lead compounds had significant shortcomings.
What was the outcome of the litigation involving amlodipine besylate?
The court upheld the validity of Pfizer’s `303 patent, rejecting Mylan’s arguments that it was invalid as obvious.
How did the settlement in the Detrol LA® case affect generic competition?
The settlement allowed generic competition to commence no earlier than January 1, 2014, and no later than March 1, 2014.
What is the significance of the POSA analysis in these cases?
The POSA analysis is crucial in determining the obviousness of a patent, as it assesses whether a person of ordinary skill in the art would have been motivated to create the claimed compound and whether the necessary modifications would have been obvious.
Sources
- Robins Kaplan, "Pfizer Inc. v. Mylan Pharms. Inc."
- Robins Kaplan, "Pfizer Inc. v. Mylan Pharms. Inc."
- CaseText, "Pfizer, Inc. v. Mylan Inc."
- CaseText, "Pfizer, Inc. v. Mylan Laboratories, Inc."
- Pfizer, "Pfizer Settles Patent Litigation with Mylan Covering Detrol LA®"
