Markush Claims in Patent Prosecution and Litigation: Leveraging Federal Court Guidance

Description

Markush practice is often used in patent prosecution and is frequently a crucial issue in patent litigation. It's a practice that allows the grouping of elements rather than having a series of dependent claims. While this practice offers financial benefits, specific issues arise, including indefiniteness, improper grouping, and double inclusion, among others.

The Federal Circuit addressed Markush claims in Multilayer Stretch Cling Film v. Berry Plastics (Fed. Cir. 2016), detailing claims construction using Markush group language. The court emphasized the closed nature of the "consisting of" terminology. This decision highlights the need to carefully construct all claim language, particularly Markush group claim language, and encourages extra caution when using any "consisting of" clause.

Further, in Shire Dev. L.L.C. v. Watson Pharma. Inc. (Fed. Cir. 2017), the Federal Circuit reversed a finding of infringement because the accused product did not meet the Markush claim element. The legal community continues to debate Markush grouping and the focus of litigation.

Listen as our authoritative panel of patent attorneys examines Markush claiming and practice, what Markush groups mean, and issues that often arise. The panel will also review the Federal Circuit opinion and its guidance and offer strategies to avoid improper Markush rejections.