The Federal Circuit has issued a precedential decision addressing whether a patent covering a given polymorph was invalid as obvious, Grunenthal GmbH v. Alkem Laboratories Ltd.  Though the Court explained that it was not establishing a categorical rule that polymorph patents can never be obvious, the case nonetheless provides important guidelines for when a polymorph patents are likely to be invalid.  For those following Revlimid®’s patent cases, the immediate question is—does the Grunenthal case have read-through to Celgene’s polymorph patents?