Civil Law

The One-Carbon Mistake That Cost A Patent Its Priority Date

Nobody likes the grammar police. Patent lawyers, unfortunately, may be the exception.

In Enanta Pharmaceuticals, Inc. v. Pfizer Inc. No. 2025-1427 (Fed. Cir. June 23, 2026), one character did a lot of damage. The difference between C2 and C1 cost Enanta the priority date of its provisional application—and led the Federal Circuit to affirm that the challenged claims were anticipated.

Turns out proofreading really can be worth millions.

But the case raises a more interesting question: Even if Enanta had … Read the rest

Civil Law

Federal Court denies samples for testing infringement of biologic process patent

The Federal Court recently refused to order a defendant to produce samples of cell culture because there was no “reasonable possibility” that testing the samples would yield evidence of patent infringement.  In pharmaceutical patent cases, testing samples of a defendant’s product – or samples from a defendant’s process – can lead to crucial evidence of infringement for trial. However, as seen in the Court’s recent decision, a defendant can resist producing samples where the plaintiff only proposes “speculative undefined tests”.   … Read the rest