Two Federal Circuit Decisions Clarify Availability of Patent Term Extension for Approved Drug Products

In two decisions issued May 10, 2010, the Federal Circuit clarified the rights of patentees to receive patent term extension (PTE) based on FDA approval of a new drug product. The Hatch-Waxman Act (as codified in 35 U.S.C. § 156) allows PTE to be granted on patents covering a drug product that was not previously approved by the FDA. To qualify for an extension, the drug product must have an “active ingredient” not previously approved by the FDA. Thus, a patent’s PTE eligibility turns, in part, on the meaning of “active ingredient” as used in 35 U.S.C. § 156(f)(2). Because these decisions clarify whether PTE may be available for drugs that may have very similar structures yet have different active ingredients as that term is defined by statute, they are potentially significant for the pharmaceutical industry.

In Ortho-McNeil Pharmaceuticals, Inc. v. Lupin Pharmaceuticals, Inc., No. 2009-1362 (Fed. Cir. May 10, 2010), and Photocure ASA v. Kappos, No. 2009-1393 (Fed. Cir. May 10, 2010), the Federal Circuit rejected the USPTO’s interpretation of “active ingredient,” which equated the term to “active moiety,” in favor of a literal construction. As applied in Photocure, this interpretation resulted in a patentee’s right to PTE based on approval of an ester salt even though a product containing a salt of the same parent acid previously had been approved. As applied in Ortho-McNeil, this interpretation resulted in a patentee’s right to PTE based on approval of an enantiomer product even when the racemic mixture was previously on the market. Thus, these decisions confirm that the court’s construction of active ingredient makes PTE more freely available than the USPTO’s interpretation would have permitted.

Photocure was initiated when the USPTO refused to extend a patent covering methyl aminolevulinate hydrochloride (MAL hydrochloride) in view of prior approval of aminolevulinic acid hydrochloride (ALA hydrochloride). Aminolevulinic acid (ALA) is the parent acid of both MAL hydrochloride and ALA hydrochloride. ALA hydrochloride is an ALA salt, while MAL hydrochloride is a salt of an ALA ester. The USPTO refused the extension because “the underlying molecule, or active moiety, [of a drug] and all of its salts and esters qualify as the same ‘product.’”

The district court disagreed with the USPTO’s active moiety interpretation of the term “product,” and found it legally incorrect. The district court noted conflicting Federal Circuit precedent, but relied on the earlier decided case, which it found to be controlling. In addition, the district court found that the plain text of the statute did not support the USPTO’s active moiety construction.

The Federal Circuit affirmed the lower court’s holding in Photocure, stating that the USPTO’s position was premised on an “incorrect statutory interpretation.” The Federal Circuit noted that the district court had “considered the separate chemical composition, the separate patentability, and the separate FDA approval” that resulted in approval for the first commercial marketing and use of MAL hydrochloride, as required by section 156. The court noted that, “even on the PTO’s incorrect statutory interpretation[,] MAL would meet the criteria for term extension, for, as the ’267 patent illustrates, the pharmacological properties of MAL differ from those of ALA, supporting the separate patentability of the MAL product.” The Federal Circuit explained that there was no conflict between earlier decisions addressing different aspects of PTE, and agreed with the district court that the USPTO interpretation was not entitled to Chevron deference “because the statute is unambiguous.”

Ortho-McNeil v. Lupin expanded the holding in Photocure by construing active ingredient in the context of racemates and their enantiomers. In that case, Lupin asserted that PTE for an enantiomer product was invalid because the FDA already had approved the racemate product, ofloxacin, before the enantiomer, levofloxacin. A racemate is a product that contains two related forms of the same molecule, called enantiomers. In the context of drug products, enantiomers may have different pharmacological properties such as different activities (therapeutic or side effects), different potencies, and so forth. Thus, one enantiomer may be more useful or more valuable than either the other enantiomer or the racemate. Lupin argued that the USPTO and FDA should not have granted PTE based on approval of the enantiomer product because the previously sold racemate contained the enantiomer as part of the racemic mixture.

The district court denied Lupin’s motion for summary judgment and granted Ortho-McNeil’s cross-motion for summary judgment, noting that the USPTO and FDA have determined that patents covering an enantiomer of a previously approved racemate are eligible for, and, in fact, have been granted, extensions. These previous extensions distinguished enantiomers from racemates and determined that they are separate active ingredients for the purposes of the Hatch-Waxman Act.

The Federal Circuit affirmed the district court’s decision and found that PTE should be granted for the protection of enantiomer products even when the racemic mixture has previously been approved by the FDA. The Federal Circuit’s reasoning is similar to the district court’s, and identified the strong precedent at the FDA for treating a drug product containing a single enantiomer as having a different active ingredient than a racemic mixture. Since the statute provides for PTE based on approval of a new active ingredient, the Federal Circuit upheld the USPTO’s determination that an enantiomer product is entitled to PTE under the Hatch-Waxman Act, even when a racemic mixture already is on the market.

These decisions have important implications for the pharmaceutical industry because they clarify when PTE is available, and generally apply the active ingredient term of the statute broadly, in accordance with its plain language. Innovators may be encouraged to seek patent protection for modifications of known drugs, and to seek PTE when such products are approved by the FDA. While the question of the scope of protection conferred by extension was not directly addressed, these decisions provide insight as to how that question will be resolved in the future. 

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