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The value of method of use patent claims in protecting your therapeutic assets

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This is a guest post by Ray Miller and Megan E. Bowers, Ph.D. at DLA Piper. Ray may be contacted at

When it comes to protecting therapeutic assets, I have long advocated for the value of method of use (MOU) and other complementary patent claims for protecting therapeutic assets. Such claims hold significant value, even relative to composition of matter (COM) patent claims, which the life sciences space often venerates above all other claim types. MOU claims and other forms of complementary protection, such as formulations, polymorphs, crystalline forms, purity claims, and complementary diagnostic claims, can provide independent and powerful protection for active pharmaceutical ingredients (APIs). Our analysis of drug approvals in the last 15 years, as well as recent court decisions, further strengthen the notion that MOU claims have value independent of COM claims.

Our analysis

We recently analyzed all small molecules (excluding Abbreviated New Drug Applications) that have received FDA approval in the United States in the last 15 years, delineated by the types of patent coverage they had received at the time of approval.


Among our findings: roughly half (51 percent) did not have COM patent protection at the time of approval. This figure alone illustrates that COM patent coverage is not necessary to advance an API, and suggests that such coverage is not required for an adequate return on investment.

Many assume that new chemical entities (NCEs) that obtain FDA approval will necessarily have COM patent protection. But even among NCEs approved within the last 15 years, 23 percent did not have COM patent protection at the time of approval, as shown in the “With NCE exclusivity” chart below.


Of the small molecules that did not receive NCE exclusivity, just 19 percent had COM coverage at the time of approval, as shown in the “Without NCE exclusivity” chart below. In comparison, 36 percent of approved small molecules that did not receive NCE exclusivity had MOU patent coverage.


Concentric circles of patent protection

As these analyses illustrate, complementary forms of patent protection, including MOU claims, are important for both scope of patent coverage and length of patent term. One can think of these layers of claim coverage and additional patent term as concentric circles of patent protection. This concept is also illustrated in the timeline below, which shows the dates and effects of innovators’ traditional attempts to add patent term and various types of claim coverage.


Recent court decisions underscore value of MOU claims

Indeed, recent court decisions have further illustrated the independent value of MOU claims. Such claims are particularly relevant to so-called “skinny labeling,” a practice that allows generic competitors to seek regulatory approval of an API for indications that are not covered by the innovator’s MOU claims.

For example, the Federal Circuit recently indicated that although skinny labeling is a viable option for generic competitors, those generics must adhere to the innovator’s MOU and indications within the confines of the skinny label. Marketing the drug as interchangeable for alternate MOUs or indications may not be permitted.

Additionally, in January 2022, the District of Delaware delivered an important decision in Amarin Pharma, Inc. et al. v. Hikma Pharmaceuticals USA Inc. et al. (1:20-CV-01630; D. Del.; Memorandum Opinion entered Jan. 4, 2022). The court granted a generic manufacturer’s motion to dismiss, finding that its product had been skinny labeled appropriately.1 Although the court dismissed the claims against the generic manufacturer, it allowed the action against an insurer to proceed under a theory of induced infringement. The insurer is accused of inducing infringement of the innovator’s MOU claims—a compelling position that upends the traditional notion that economic incentives alone are insufficient to establish induced infringement. Insurers are watching this case closely; the court’s refusal to dismiss the claims against the insurer may ultimately chill the industry’s common practice of generic substitution. The court’s decision, and the effects it may have, emphasize the standalone value of an innovator’s MOU patent claims.

Our analyses and the cases discussed above illustrate the importance of MOU patent claims, distinct and independent from the traditionally valued COM claims. One wonders how many important therapeutics may have been abandoned or otherwise shelved because of innovators’ hesitancy to rely on MOU patent coverage alone, without corresponding COM coverage. MOU claims can offer robust protection throughout a small molecule’s life cycle, from approval to the entry of a generic competitor. Innovators and their counsel would be wise not to overlook the value of MOU claims and other types of complementary coverage as they build protection around their therapeutic assets.

1 My colleague Michael Sitzman explores this opinion in more detail in “Skinny enough? Amarin v. Hikma reexamines induced infringement with carveout labels.”

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