United States: Crafting Method Of Treatment Claims To Avoid Multiple Actors

Originally appeared in Law360 on September 17, 2015.

In Limelight Networks Inc. v. Akamai Technologies Inc., the U.S. Supreme Court reversed an en banc decision of the Federal Circuit, which had held that a party may be liable for inducing infringement under 35 U.S.C. § 271(b) if it carries out some steps of a patented method claim and encourages others to carry out the remaining steps of the patented method. 134 S. Ct. 2111, 2116-18 (2014). Under the Federal Circuit's standard, a party could be liable for inducing infringement, even in the absence of a direct infringer practicing the entire patented method. The Supreme Court rejected the Federal Circuit's view, adhering instead to the principle that liability for inducement may arise only where direct infringement occurs. Id. at 2118. The Supreme Court, however, invited the Federal Circuit to revisit its precedent (Muniauction Inc. v. Thomson Corp., 532 F.3d 1318 (2008)), which held that liability for direct infringement under Section 271(a) requires performance of all steps of a method patent to be attributable to a single entity. Limelight, 134 S. Ct. at 2120.

On remand from the Supreme Court, in Akamai Technologies Inc. v. Limelight Networks Inc., the Federal Circuit, sitting en banc, ruled that "[d]irect infringement under § 271(a) occurs where all steps of a claimed method are performed by or attributable to a single entity." 2015 WL 4760450 (Aug. 13, 2015), at *1. When there are multiple actors involved in practicing the steps, the court stated that "a court must determine whether the acts of one are attributable to the other such that a single entity is responsible for the infringement." Id. The court set forth two sets of circumstances where an entity will be responsible for other's performance of method steps: "(1) where that entity directs or controls others' performance, and (2) where the actors form a joint enterprise." Id.

The Supreme Court's Limelight decision together with the Federal Circuit's en banc decision on remand could pose challenges to the enforcement of certain method of treatment patents that may require more than one actor to perform all of the claimed steps. For example, patents involving personalized medicine — where a diagnostic test is often employed for selecting appropriate and optimal therapies based on a patient's genetic information or other molecular or cellular analysis — may claim steps of testing patients with a diagnostic test to identify those having a particular genetic trait and then administering the drug to only those patients. But the actor conducting the diagnostic test may be different from the actor administering the medicine and, depending on circumstances, the acts may not be attributable to, or controlled by, a single entity. If no single entity is responsible for all of the claimed steps there would be no direct infringement. And if there is no underlying direct infringement there would be no inducement.

When drafting claims to cover methods of treatment, it is therefore crucial to ensure that one has claims that do not require multiple actors. Let us assume there is a drug A used to treat prostate cancer for patients with a specific genetic mutation B as identified by a diagnostic test. Here are examples of three claims that can be crafted to avoid multiple actors:

1. A method for treatment of mutation B-positive prostate cancer comprising a step of administering to a human in need thereof an effective amount of drug A.

2. A method for treatment of mutation B-positive prostate cancer comprising a step of administering to a patient who has been identified as having mutation B-positive prostate cancer an effective amount of drug A.

3. A method for treatment of mutation B-positive prostate cancer comprising the steps of selecting a patient who has mutation B-positive prostate cancer, and administering to said selected patient an effective amount of drug A.

In claims 1 and 2, the treatment step consists of administering the drug A to patients who already have been identified as having mutation B-positive prostate cancer. No separate step of testing the patients for mutation B is recited. In claim 3, the "selecting" and the "administering" steps are likely conducted by the same entity, i.e., the doctor who selects the patient who has already been identified as having mutation B-positive prostate cancer and then administers the drug to the patient. Thus, multiple actors are not involved in performing the recited steps.

An accused infringer may argue that in the illustrative claims above, there is an implicit step of testing for patients having mutation B, which is performed by a different actor. To counter this argument one should also have claims that explicitly require an initial testing step to determine whether a patient has mutation B. By doing so, one can invoke the doctrine of claim differentiation to help to construe the claims that do not have an explicit testing step as excluding such a step. The doctrine of claim differentiation creates a presumption that each claim of a patent has different scope. When "a patent claim 'does not contain a certain limitation and another claim does, that limitation cannot be read into the former claim in determining either validity or infringement.'" See SunRace Roots Enterprise Co. v. SRAM Corp., 336 F. 3d 1298, 1302-03 (Fed. Cir. 2003).

Here are examples of claims that can be added to invoke the doctrine of claim differentiation:

4. The method of claim 1 further comprising a step of testing a human to determine whether said human has mutation B-positive prostate cancer prior to said administering step.

5. The method of claim 2 further comprising a step of testing patients to identify a patient having mutation B-positive prostate cancer.

6. The method of claim 3 further comprising a step of testing a patient to determine whether the patient has mutation B-positive prostate cancer.

Claims 4, 5 and 6 all contain an explicit testing step to determine whether a patient has mutation B, thereby creating a presumption that this testing step cannot be read into the respective independent claims (claims 1, 2 and 3) from which they depend.

The Supreme Court and the Federal Circuit decisions in the Limelight cases pose challenges for the enforcement of method of treatment claims that may require multiple actors to perform all of the recited steps. With artful claim drafting and the help of claim differentiation, however, one can obtain claims that can be construed as requiring only a single actor and potentially avoid this issue in litigation.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.