Intrinsic Evidence Decodes Disputed Claim Terms

Holding

In Newron Pharms. v. Aurobindo, No. 21-cv-843 (D. Del. April 14, 2023), the District Court of Delaware addressed several disputed terms in a patent related to the treatment of idiopathic Parkinson's disease. Based on the intrinsic evidence, the Court agreed with Plaintiff’s proposed construction of terms like “stable dose of levodopa,” “maintaining,” and “a therapeutically effective stable dose of levodopa.”  

Background

Plaintiffs Newron Pharmaceuticals sued MSN Laboratories for infringement of U.S. Patent No. 8,076,515 (“the ’515 patent”), U.S. Patent No. 8,278,485 (“the ’485 patent”), and U.S. Patent No. 8,283,380 (“the ’380 patent”). Before the court was the issue of claim construction.

1. “Stable Dose of Levodopa” of the ’380 patent

The first term in dispute was “stable dose of levodopa.” The claim at issue recites:

1. In a method of treating idiopathic Parkinson's disease in a patient receiving a stable dose of levodopa, the improvement comprising: concurrently administering safinamide, or a pharmaceutically acceptable salt thereof, on an oral dosage schedule of about 0.5 mg/kg/day to about 5 mg/kg/day, while maintaining the patient on a stable dose of levodopa.

Plaintiffs argued that “stable dose of levodopa” meant a dose that neither increased nor decreased. Id. at *4. Defendants claimed that the term was indefinite due to the lack of specific information on duration and frequency. Id.

The court analyzed the patent claims, noting that the use of the terms “maintaining” and “therapeutically effective” in the claims implied an unchanged dose. Id. The specification mentioned a clinical trial with patients on stable doses of dopamine agonist for at least four weeks, indicating that stable doses remained unchanged. Id. at *5.

The prosecution history supported the interpretation of a stable dose as an unchanged dose of levodopa. Id. The examiner considered that a stable dose referred to a dose that is neither increased nor decreased. Id. Considering the intrinsic record, including claims, specification, and prosecution history, the court concluded that “stable dose of levodopa” meant a dose that did not change. Id. Here, Defendants' argument of indefiniteness failed to show how one of ordinary skill in the art would not understand the claims’ scope. Id. at *6. Moreover, the court found that the specification provided “an objective anchor” allowing one of ordinary skill in the art to determine the boundaries of the claim. Id.

2. “Maintaining” the ’380 patent

The second term in dispute was “maintaining.” The claim at issue recites:

1. In a method of treating idiopathic Parkinson's disease in a patient receiving a stable dose of levodopa, the improvement comprising: concurrently administering safinamide, or a pharmaceutically acceptable salt thereof, on an oral dosage schedule of about 0.5 mg/kg/day to about 5 mg/kg/day, while maintaining the patient on a stable dose of levodopa.

Plaintiffs argued that “maintaining” should be understood as “keeping,” while Defendants claimed it was indefinite. Id.

The court analyzed the intrinsic record to determine the meaning of “maintaining.” Examining the patent claims, it found that “maintaining” referred back to the prior art method, requiring the patient to stay on the same stable dose of levodopa. Id. Dependent claim 5 further supported this, mandating maintenance of the stable dose for at least 12 weeks. Id. at *6-7.[1]

The specification also used “maintaining” in other contexts to mean “keeping,” such as maintaining balance and pH levels. Id. This supported the interpretation of “maintaining” as “keeping” with respect to dosage. During patent prosecution, Applicant distinguished the invention from the cited prior art on the basis of maintaining the levodopa dose without reduction when additional agents were added. Id. Therefore, based on the intrinsic record, the court concluded that “maintaining” meant “keeping.” Id.

Defendants’ indefiniteness argument failed again because they did not show why one of ordinary skill in the art would not understand the claims’ scope. Id.

3. “A Therapeutically Effective Stable Dose of Levodopa” of the ’380 patent

Another term in dispute was “a therapeutically effective stable dose of levodopa.” The claim at issue recites:

2. A method of treating idiopathic Parkinson's Disease comprising: administering a therapeutically effective stable dose of levodopa; and concurrently administering safinamide, or a pharmaceutically acceptable salt thereof, on an oral dosage schedule of about 0.5 mg/kg/day to about 5 mg/kg/day.

Plaintiffs proposed construing the term as “a dose of levodopa sufficient to treat idiopathic Parkinson's disease that was neither increased nor decreased.” Defendants argued that the term was indefinite. Id.

The court examined the intrinsic record to determine the meaning of the term. Claim 2 of the patent described a method of treating Parkinson's disease by administering a “therapeutically effective stable dose of levodopa” concurrently with safinamide. The specification mentioned treatment kits that included a therapeutically effective dose of levodopa and other Parkinson's agents. The prosecution history explained that a “therapeutically effective” dose referred to a clinically-relevant dose that effectively treated Parkinson's disease. Id. at *8.

Based on the intrinsic evidence, the court concluded that the term “a therapeutically effective stable dose of levodopa” referred to a dose of levodopa that was sufficient to treat idiopathic Parkinson's disease and remained unchanged, neither increased nor decreased. The court adopted Plaintiffs' proposed construction. Id.

The court found that Defendants failed to provide any evidence or support for their assertions regarding the claims' scope. Id. Therefore, the court did not find “a therapeutically effective stable dose of levodopa” to be indefinite. Id.

4. “High purity” of the ’515 and ’485 patents

The parties disputed the meaning of the phrase “high purity” in relation to disputed terms of the '515 and '485 patents. Id. The claim at issues recites:

32. High purity safinamide or ralfinamide or a pharmaceutically acceptable acid salt thereof with a content of the respective impurity (S)-2-[3-(3-fluorobenzyl)-4-(3-fluoroberizyloxy)-benzylarnino]propanamide (IIa) or (S)-2-[3-(2-fluorobenzyl)-4-(2-fluorobenzyloxy)-benzylamino]propanamide (IIb) [graphic omitted] or their pharmaceutically acceptable acid salts, which is lower than 0.03% (by weight).

Plaintiffs argued that “high purity” referred to safinamide and ralfinamide preparations with less than 0.03% by weight of impurities. Id. at *8-9. Defendants contended that “high purity” referred to the overall chemical purity of a safinamide preparation and claimed that the term was ambiguous and therefore indefinite. Id. at *9.

The court examined the claims and specification and found that claim 32 of the '515 patent specified “high purity safinamide or ralfinamide” with impurity levels below 0.03% by weight. The court noted that the language of the claim indicated the inventors' discovery of a new process for maintaining specific toxic impurities below the specified threshold in large-scale preparations of safinamide and ralfinamide. Id. This interpretation was supported by the consistent usage of phrases like “high purity,” “highly pure,” and “high purity degree” in the specification, all referring to preparations with less than 0.03% by weight of impurities IIa and IIb and their salts. Id. at *9-10.

The court rejected Defendants’ argument that the term “high purity” referred to an undefined level of overall chemical purity. It emphasized that Defendants' reliance on expert testimony divorced the claim construction from the intrinsic record, which is the primary guide for determining the meaning of disputed terms. Id. at *10. Additionally, the court highlighted that the specification contained examples related to the chemical synthesis of safinamide or ralfinamide with a “high purity degree,” specifically referring to the content of impurities IIa and IIb by weight. Id.

The court rejected Defendant’s claim differentiation argument, noting that claim differentiation “is a guide, not a rigid rule, and does not alter a construction otherwise compelled by the intrinsic record.” Id. at *11.

Takeaway

This court decision emphasizes the significance of using clear and definite language in claim terms. To construe the claim terms, the court looked to the intrinsic record, including the claims, specification, and prosecution history, to determine the intended meaning of the term. The Federal Circuit’s comment that the specification is “the single best guide to the meaning of a disputed term” reflects important guidance for patent drafters. Phillips v. AWH Corp., 415 F.3d 1303, 1315 (Fed. Cir. 2005) (en banc), quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996). Choosing language carefully will help defeat any indefiniteness challenges as well as achieve the goal of having the court construe the claims as intended.

The court also emphasized the presence of objective reference points in the intrinsic record to determine the meaning of the disputed claim terms:

Descriptive words and terms of degree do not render a claim indefinite if there is adequate objective guidance regarding the boundaries of the claim. See Niazi Licensing Corp. v. St. Jude Med, 30 F.4th 1339 , 1347 (Fed. Cir. 2022); see also Guangdong Alison Hi-Tech v. ITC, 936 F.3d 1353 , 1359 (Fed. Cir. 2019) . . . In some circumstances, a person of ordinary skill can ascertain an invention's boundaries from exemplary designs or specific examples offering an "objective anchor" for comparison. Niazi, 30 F.4th at 1348 (internal quotation marks omitted).

Newron, at *5-6.

In this case, the specification and prosecution history provided a specific time frame of four weeks as an objective anchor for understanding the term “stable dose.” The court considered this reference point as a basis for determining the scope of the claim. This highlights the significance of providing objective guidance and reference points in the patent specification to assist in the interpretation of claim terms.

Endnotes

[1] Claim 5. The method of claim 1 or claim 2, wherein safinamide, or pharmaceutically acceptable salt thereof, is administered for at least 12 weeks.