Draft One Claim Before You File the Provisional
Authored by Babak Akhlaghi on July 20, 2026. On June 23, 2026, the Federal Circuit affirmed that a single digit invalidated Enanta’s patent covering a coronavirus protease inhibitor. The provisional recited a C2-C12 alkyl group. The later patent recited C1-C12. The court held the provisional gave no written description support for the C1 compound, so the patent lost its priority date. Pfizer’s earlier disclosure of nirmatrelvir then anticipated the claims.
Enanta’s provisional was detailed and meticulous. The failure was narrow: the key aspect of the invention was captured incorrectly, and nobody caught it before filing.
Why Claims Belong in Your Provisional
Most practitioners treat claims as a non-provisional task. Claims are optional in a provisional, and under budget pressure they get deferred.
That deferral creates a blind spot. Your non-provisional claims must have written description support in the provisional. You cannot verify that support if you have never articulated the claim.
Drafting even one independent claim at the provisional stage solves this. Writing that claim requires a conversation with your inventors about the core aspects of the technology. That conversation is the safeguard. It surfaces the question that catches a C2 that should be a C1.
Thoughtful provisional claims also strengthen priority rights and focus the entire drafting effort. Once the claim exists, you move forward knowing the core of your invention has support in the later filing.
The Three-Step Playbook
1. Draft claims in the provisional. Include at least one independent claim and several key dependent claims. Have every inventor review the claims and flag errors. Inventors know their compounds. Practitioners know claim structure. You need both sets of eyes.
2. Use AI as a consistency auditor. Use it to check, and let humans draft. Run the specification through AI to flag typographical errors and inconsistent usage of chemical compounds across the document. Enanta’s spec defined “alkyl” one way in one section and contradicted it in another. A consistency check surfaces exactly that.
3. Slow down and layer your review. Multiple review passes. Practitioner review first, then inventor review and written approval. In chemistry, a one-carbon difference means a different compound with different properties. The error looks small on the page and is significant in substance.
💡 Tip: schedule inventor sign-off as a formal step before filing, not an informal read-through.
The Question to Answer Before You File
Ask yourself: what exactly are you claiming?
If you cannot answer that question from the four corners of the provisional, you are not ready to file.
Speed matters under the first-to-file system, especially in hot spaces like AI, biotech, and therapeutics. Speed without accuracy produced the Enanta result: a rushed core disclosure inside a polished document. A rushed provisional carries consequences that surface only when a competitor forces the issue.
Your provisional is your ceiling. Draft the claim, run the audit, get inventor approval, then file. That discipline costs you days now and protects the priority date that everything else depends on.
📖 Further reading: Patent Strategy for Startups — How to Build IP That Actually Creates Leverage
