Purdue Pharma L.P. v. Teva Pharms. USA, Inc.

The asserted claims of patents covering reformulated OxyContin were infringed but found to be invalid.

Spring 2014

GENERICally Speaking

Case Name: Purdue Pharma L.P. v. Teva Pharms. USA, Inc., Civ. Nos. 11-2037-SHS; 12-5083-SHS, 2014 U.S. Dist. LEXIS 5031 (S.D.N.Y. Jan. 14, 2014) (Stein, J.)

Drug Product and Patent(s)-in-Suit: OxyContin® (oxycodone); U.S. Patents Nos. 7,674,799 (“the ’799 patent”), 7,674,800 (“the ’800 patent”), 7,683,072 (“the ’072 patent”), 7,776,314 (“the ’314 patent”), and 8,114,383 (“the ’383 patent”) 

Nature of the Case and Issue(s) Presented: The court addressed the patents in suit in two groups. The low-ABUK patents included the ’799, ’800, and ’072 patents. Those patents claim an oxycodone salt with extremely low levels of the impurity 14-hydroxycodeinone (“14-hydroxy”). The second group included the ’314 and ’383 patents, which claim the manufacture of tablets resistant to abuse by users. The court separately considered the infringement and validity of each group of patents.

In the low-ABUK portion of the trial, Purdue claimed that Teva infringed claims 3 and 19 of the ’799 patent, claims 30–34 and 76–79 from the ’800 patent, and claims 1, 4, and 5 of the ’072 patent. In the abuse-proof portion of the trial, Purdue claimed that Teva infringed claims 1, 2, 5, 7, and 8 of the ’383 patent. Those claims described a thermoformed pharmaceutical dosage form durable enough to withstand forces as strong as 500 Newtons (500N) without breaking. Finally, Purdue claimed Teva of infringing claims 1, 2, 6, and 9 of the ’314 patent. Those claims were related to a pharmaceutical dosage form that deterred abuse by transitioning into a viscous gel when dissolved in a liquid.

The court presided over a 3-week bench trial. The parties focused their presentations on the abuse-proof patents. Because Teva was not a party to an earlier 2012 trial, it had the opportunity to present additional evidence in relation to the low-ABUK patents. The court held that claims 3 and 19 of the ’799 patent, claims 30–34 and 76–79 of the ’800 patent, and claims 1, 4, and 5 of the ’072 patent were invalid. The court also held that Teva’s proposed generic product did not infringe claims 1, 2, 6, and 9 of the ’314 patent, and that claims, 1, 2, 5, 7, and 8 of the ’383 patent were invalid.

Why Teva Prevailed:  The court first addressed the low-ABUK patents. The court provided an overview of Purdue’s attempts to synthesize oxycodone hydrochloride while eliminating the presence of a chemical impurity and potentially dangerous by-product known as 14-hydroxy. All three low-ABUK patents were filed as continuations of application No. 11/391,897, otherwise known as the “Chapman Application.”

Regarding defendants’ anticipation argument, the court determined that there were two significant differences between the prior art and the patented claims. Firstly, the court concluded that the prior art did not disclose the existence of ABUK or teach that it converts to 14-hydroxy. Secondly, the prior art did not disclose oxycodone substantially free of 14-hydroxy. Accordingly, the court held that the asserted claims that combine oxycodone with low levels of 14-hydroxy were distinct from the prior art.

The court next held that Teva’s ANDA infringed all asserted claims of the ’800, ’072, and ’799 patents due to the fact that Teva’s generic drug contained a non-zero amount of 14-hydroxy.

Concerning the issue of obviousness, the court found that at the time of the invention, a person of ordinary skill in the art (“POSA”) would have known that the FDA desired low-ABUK oxycodone. At the time of the invention, a POSA had command of the techniques necessary to convert 14-hydroxy to oxycodone. These techniques had been used both for the purpose of synthesis and for the purpose of purification. However, the court concluded their success, borne of common sense and guided by routine experimentation, was not more than a predictable use of prior-art elements according to their established functions. It was also apparent at the time of invention that the FDA would call on manufacturers to produce a low-ABUK version of oxycodone. The court determined that it would have been obvious to a POSA to hydrogenate at or during the salt-formation step. Lastly, the court noted that the patent claims extended to the obvious, even if they could be practiced in a nonobvious way. What matters was the objective reach of the claim. Instead of claiming ABUK directly, Purdue claimed low-ABUK oxycodone in various forms. Its contribution to the science of that reaction was to identify additional explanations for why known techniques, used for their known purpose, would create the product. Invention requires something more.  Accordingly, the court held that Teva had established a prima facie case of obviousness with respect to the low-ABUK class of patents.

Purdue’s attempts to rebut the court’s finding of prima facie obviousness with secondary considerations of non-obvious were also unsuccessful. Commercial success could not be attributed to low-ABUK oxycodone because Purdue never marketed OxyContin on the basis of its low-ABUK features. There was no record evidence of any long-felt, unmet need for low-ABUK oxycodone. The evidence demonstrated a need for low-ABUK oxycodone, but once the FDA established a low-ABUK target, Purdue promptly met it.  Ultimately, the court concluded that the products covered by the low-ABUK patents were merely improvements, but did not constitute true inventions. Low-ABUK oxycodone stood within reach of any POSA with the desire to use routine science and common sense to improve the existing oxycodone product.

Next, the court addressed the abuse-proof patents. OxyContin was especially susceptible to tampering, because abusers could crush the tablets easily into powder, thereby circumventing the timed-release aspect of the tablet, and resulting in rapid release of the opioid active ingredient. Purdue began to develop its anti-abuse strategies in the 1990s. It considered (i) increasing the hardness of the pills and (ii) adding a compound that caused the drug to turn into a viscous gel if a user attempted to dissolve the pill in water. After incorporating these safeguards, Purdue submitted a NDA in 2007, which was approved by the FDA in April 2010. Purdue released the reformulated version of OxyContin four months later. The FDA eventually withdrew all previous versions of OxyContin in favor of the new, anti-abuse version.

The court next addressed whether Teva’s ANDA product infringed the ’383 patent, which claimed the hardening process that made the pills difficult to crush. The court noted that, much like the patented process, Teva compressed and then cured its tablets, which made them extremely hard and difficult to crush. The only distinction between Teva’s process and the patented one involved splitting or swapping of steps on a flow chart, which the court felt was not meaningful to the function, way, or result of the claim limitation. Accordingly, the court held that Teva’s ANDA product would infringe all of the asserted claims of the ’383 patent.

But the court also held that the asserted claims of the ’383 patent were invalid as anticipated and obvious. The heat-extrusion process disclosed in a 1995 application filed with WIPO (“the McGinity application”) anticipated the ’383 patent. Although the McGinity reference was not specifically directed toward the formulation of opioid drugs, the application disclosed that it could include opioids.  The court was especially persuaded by the fact that the McGinity application was specifically directed toward ingredients that were susceptible to abuse.  Purdue argued that the McGinity application did not include a specific breaking strength. The court was not persuaded, finding that it inherently disclosed a breaking strength in excess of 500N. Additionally, the court held that the ‘383 patent was obvious because public demand for an extremely hard version of a controlled-release opioid tablet would have given motivation to a POSA to create the alleged invention. The interest in a tamper-resistant dosage form of oxycodone was well-documented at the time of invention. The court found by clear and convincing evidence that the prior art included evidence of motivation and the capability to invent the ’383 patent’s claimed invention.

Purdue’s rebuttal evidence of secondary considerations of non-obvious was not persuasive. Purdue provided no evidence that reformulated OxyContin had been more commercially successful than the original OxyContin that came before it. A comparison of the data for OxyContin sales and pricing before and after the 2010 introduction of reformulated OxyContin did not show increased sales or an increased price. Moreover, Purdue did not provide any evidence of a nexus between that hypothetical sales increase and the patented feature. The court also found that the two-and-a-half-year period between the public health crisis observed in 2001 and the time of the patent application in 2003 did not give rise to a long-felt need.

Finally, the court analyzed the ’314 patent, which claimed OxyContin pills’ becoming viscous gels if a drug abuser attempted to dissolve them in water. The court took issue with Purdue’s gel test for infringement, finding that the testing protocol proffered by Purdue had embedded ambiguities and biases that undercut any experimental results emerging from the protocol. The court was particularly troubled with video evidence of the test’s being performed where the lab technicians appeared to commit multiple errors during the testing protocol. Because of the court’s concerns with the manner in which the gel test was performed, it accorded it no weight and determined that Teva’s generic formulation did not infringe. Despite this finding, the court held that the patent was invalid for not meeting the definiteness of Section 112.

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