In yet another decision examining the boundaries of patent-eligible subject matter under 35 U.S.C. § 101, the Federal Circuit determined in Classen Immunotherapies v. Biogen IDEC that two representative claims directed to comparing immunization schedules, choosing a schedule, and immunizing a patient based on that schedule, constitute patent-eligible subject matter. Because these two claims included the step of immunization based on a selected schedule, they were directed to “a specific, tangible application.” The court further held that the third representative claim, which did not include the immunization step, did not encompass patent-eligible subject matter.

The patents at issue in Classen cover methods for determining the effect of particular immunization schedules on the incidence or severity of chronic immune-mediated disorders. One representative claim of the Classen patents, designed to assess the relative safety of such immunization schedules, comprises administering a vaccine to specific subjects and comparing the incidence of these disorders (as well as any adverse effects) with those in a control group. The other two representative claims covered identifying two groups of mammals that had been immunized according to different schedules, comparing the effects of those schedules in order to select one, and then immunizing a subject in accordance with the selected schedule.