Obtaining a patent term extension (PTE) is extremely valuable to an innovator. By design, PTE extends the patent term to recoup time lost to the rigorous regulatory development and approval phases required for drugs, biologics and certain medical devices. But what does a patentee actually receive during the PTE period? Innovators should note that their rights during the extension period are limited in certain ways:

  • PTE covers only uses of the product that would otherwise be subject to a regulatory review period.

  • PTE covers only the approved use of the product.

  • PTE covers the product, including any salt or ester of the product.

All Rights. At the outset, the term of the entire patent is extended, not just individual claims.1 This extension applies to all rights a patentee may enjoy, not merely the right to exclude others from practicing the claimed invention.2

Pharmaceutical Uses. Because PTE compensates a patentee for patent term lost due to delays in the regulatory process for products subject to pre-market approval, all rights of the patent are extended, but they are limited to the approved use of the product.3 “The ‘rights derived’ provision of § 156(b) specifically limits the extension to ‘any use approved for the product,’ which means that other (e.g., non-pharmaceutical) uses are not subject to the extension.”4

For example, during the extension period, a patentee could assert an infringement claim of a composition-of-matter patent against a third party, so long as the third party was using or marketing the compound as a drug. In contrast, if the third party was using or marketing the compound as a pesticide ingredient, the patentee would not have any recourse against the third party during the extension period.

What if the third party was marketing the compound as a dietary health supplement? The legislative history and case law suggest that the patentee would not have any recourse during the extension period because the dietary health supplement is not a use for which a regulatory review period would have been required.

Approved Uses. The statute states that, for patents that claim a product, the rights derived are “limited to any use approved for the product (A) before the expiration of the term of the patent (i) under the provision of law under which the applicable regulatory review occurred, or (ii) under the provision of law under which any regulatory review described in paragraph (1), (4), or (5) of subsection (g) occurred, and (B) on or after the expiration of the regulatory review period upon which the extension of the patent was based.”5

The extension will cover only the uses that have been approved for the product before the extended patent term expires. If an applicant obtains approval of its drug for rheumatoid arthritis, then a patent covering the drug could be enforced during the extension period against a third party marketing the drug for rheumatoid arthritis. However, if a third party seeks approval and markets the drug for a different indication, such as atopic dermatitis, after undergoing a regulatory review period, would the patentee have any recourse?

The statutory language suggests that, if the third party obtains approval for the second indication before the extended term expires, and the second indication is subject to a regulatory review period (as either a drug, antibiotic or biologic; new animal drug; or veterinary biological product), then the second indication would be covered during the PTE period.6 Notably, regulated uses for medical devices are not included in part (ii) of the statue.

Product. In a more expansive approach, the rights under the extended patent term apply to any salt or ester of the patented moiety.7 In Pfizer v. Dr. Reddy’s, Pfizer had a patent covering amlodipine and obtained PTE on that patent based on the regulatory review period required for amlodipine besylate. Dr. Reddy’s sought approval of amlodipine maleate as a generic of amlodipine beyslate. The Federal Circuit held that PTE applies to the “drug product,” which is defined in 35 U.S.C. § 156(f) as the active ingredient, including any salt or ester thereof.8 The court found that the drug product was amlodipine and Dr. Reddy’s was seeking approval of the maleate salt of amlodipine, thereby infringing Pfizer’s patent covering amlodipine.

Innovators should consult with both patent and regulatory counsel to understand the scope of any PTE award. Additionally, innovators should consider employing strategies to attempt to mitigate the risk of a third party exploiting the inherent limitations of a PTE award.