Salt and solid form issues in US and European patents

Jonathan Roses (pictured, left), counsel Wolf, Greenfield & Sacks and Matthew Birkett, partner, Hoffmann Eitle, provide an Expert View on general treatment of salt and polymorphic forms in the US Patent and Trademark Office, the European Patent Office and the courts.

Patent applications are often filed during the lead discovery and optimization stages of the drug discovery process, when a group of compounds is being evaluated, but before a lead candidate has been identified.

As a result, such applications usually claim a chemical genus encompassing a number of compounds, and often include generic language stating that the compounds can be provided in various forms, such as pharmaceutical salts and solid forms (eg, polymorphs, solvates, and hydrates).