Paragraph IV and ANDA Litigation Checklist: A Practical Checklist

Document type: Checklist Practice area: Intellectual Property — Patents Jurisdiction: United States (federal) Last reviewed: 5 September 2026

Part 1 — Generic: the landscape

Pull the Orange Book listing for the reference drug: every patent, expiration, use code, listing date.
Pull the full patent families, including unlisted patents (assertable, but outside this framework), continuations, and foreign counterparts.
Map every regulatory exclusivity: new chemical entity (5 years; 4 for a Paragraph IV filing), new clinical investigation (3 years), orphan (7 years), pediatric (6 months, additive).
Compute the entry date as the latest of all patents and all exclusivities, not the last patent to expire.
Check patent term extension under 35 U.S.C. § 156: which patent, and how the calculation ran.
Determine the first eligible filing date.
Assess who else is likely to file — shared exclusivity changes the economics.
Model the value of 180-day exclusivity assuming an authorized generic launches on day one.

Part 2 — Generic: the technical work

Design the formulation around the listed formulation patents.
Document every formulation trial contemporaneously, with the design-around rationale stated in the development record. This is the non-infringement case.
Characterize the product analytically for any polymorph or crystalline form patent, using both the patent's methods and independent methods.
Run a thorough prior art search on every listed patent, separating printed publications (usable at the PTAB) from prior products and public uses (court only).
For each method-of-use patent, read the use code carefully and determine whether a section viii carve-out is available.
If the use code appears broader than the patent claims, consider the Caraco Pharmaceutical Laboratories, Ltd. v. Novo Nordisk A/S, 566 U.S. 399 (2012) counterclaim.
Draft the proposed label after the carve-out and review what remains.
Confirm the safe harbor under 35 U.S.C. § 271(e)(1) covers the development work performed.

Part 3 — Generic: the certifications

For each listed patent, decide and record the reasoning:

Paragraph I — no patent information filed.
Paragraph II — patent expired.
Paragraph III — concede; approval at expiry; no litigation on that patent.
Paragraph IV — invalid, unenforceable, or not infringed; starts a lawsuit.
Section viii statement — method-of-use patent carved out of the label.
Confirm the certification set is strategic: challenge the patents that control the date, concede the rest.
Confirm the set preserves first-filer status if exclusivity is the objective.
Confirm each Paragraph IV has a genuine, articulable basis.

Part 4 — Generic: the notice letter

Identify the ANDA and the drug product.
For each Paragraph IV patent, provide a detailed statement of the factual and legal basis.
Claim-by-claim non-infringement analysis, describing the ANDA formulation at the level needed.
Invalidity contentions applied claim by claim, with the art.
Include a reasonable offer of confidential access to the ANDA.
Serve on the NDA holder and every patent owner.
Log the date of service and confirm receipt — both clocks run from receipt.
Confirm every position you may later assert appears here; contentions absent from the letter draw timeliness arguments.
Resist padding. Two strong grounds beat three hundred pages.

Part 5 — Brand: the 45 days

Days 1–3:

Log the receipt date precisely. The 45-day window and the 30-month stay both run from it.
Distribute to litigation, regulatory affairs, and the business.
Identify which patents are certified to and how; note any section viii statement.
Determine whether this applicant is a first filer.

Days 3–10:

Negotiate and execute the confidential access agreement — this week, not next month.
Obtain the ANDA.
Assign formulation, analytical, and regulatory review.

Days 10–35:

Assess infringement of each certified patent against the ANDA as described in the application.
Assess the invalidity contentions and identify the weak ones.
For any carved-out method patent, assess induced infringement: what remains in the proposed label; what the applicant has said publicly.
Preserve the applicant's website, press releases, investor presentations, and call transcripts with dated capture — they change and disappear.
Decide which patents to assert.

Days 35–44:

File the complaint. The stay is the point; file unless there is no colorable position on any patent.
Choose venue deliberately.
Sue every pending filer.

Part 6 — Scheduling against the stay

Calendar the stay expiration date and put it on every schedule.
At the Rule 16 conference, propose a schedule producing a decision before expiry.
Address consolidation or coordination of multiple filers: joint validity, individual non-infringement.
Negotiate a protective order with a prosecution bar and tiered confidentiality — the ANDA and the manufacturing process are trade secrets on both sides.
Consider combining claim construction with summary judgment to save months.
Confirm there is one named person accountable for the stay date and the schedule against it.

Part 7 — Discovery

Brand seeks:

The complete ANDA and every amendment: formulation, process, analytical methods, stability, dissolution, proposed label.
Batch records and product samples for independent testing.
Development documents: formulation selection rationale, alternatives tried, design-around intent.
FDA correspondence, including deficiency letters and responses.
Marketing, launch planning, and sales projections.
All public statements about the product.

Generic seeks:

Prosecution files for every asserted patent, including foreign counterparts.
Brand formulation and development records — relevant to obviousness.
Commercial success evidence and its basis.
Prior art in the brand's possession, including from foreign proceedings.
Orange Book listing decisions and use code determinations.
Prior settlements and licenses with other filers.
Obtain and test samples early. Testing takes weeks and the results shape everything.

Part 8 — Claim construction and trial

Construction:

Identify range limitations and, critically, the measurement point — before or after which processing step.
Identify compositional terms where a component serves two functions.
Identify polymorph definitions and which analytical method controls.
Mine the prosecution history for disclaimer, across the whole family.
Assess whether construction is dispositive; if so, propose a combined construction and summary judgment schedule.

Trial:

Confirm this is a bench trial — no damages, no jury.
Prepare a technology tutorial.
Build demonstratives showing the actual composition against the claim.
Develop secondary considerations seriously: commercial success, long-felt need, failure of others, unexpected results.
Address obviousness-type double patenting; it does real work in this field.
Preserve the record for appeal — construction is reviewed de novo, findings for clear error.

Part 9 — The skinny label

Generic scrub list, all reviewed by counsel before launch:

The proposed label: does anything remaining relate specifically to the carved-out indication — dosing tables, pharmacology, clinical studies, warnings?
Product catalogs and monographs.
Website and product pages.
Press releases and investor presentations — "a generic version of [brand]" is the exposure.
Analyst call scripts and Q&A preparation.
Sales training and detailing materials.
Payer and formulary submissions, including therapeutic equivalence statements.
Compendia entries the company can influence.
Package inserts, cartons, and artwork.
Document the review in a memorandum.
Train the commercial team on what they cannot say.

Brand's record:

Dated capture of the generic's website, catalog, and product pages.
Every press release, investor presentation, and call transcript.
Line-by-line label comparison identifying every retained element relevant to the carved-out use.
Marketing materials obtained in discovery.
Evidence of actual use and substitution.

Part 10 — The PTAB decision

Is the prior art printed publications (usable) or prior use and on-sale (not usable in an IPR)?
Is the district court trial date before the Board's statutory deadline? If so, expect discretionary denial risk.
Model 35 U.S.C. § 315(e) estoppel: which district court invalidity grounds would be lost?
Is the primary defense non-infringement? If so, weigh carefully — the Board cannot decide it.
Confirm the IPR does not affect the 30-month stay or FDA approval.
Assign one person to check every filing across both tracks for claim position consistency.

Part 11 — At-risk launch

Before launching with an appeal pending:

Expected revenue during the appeal period.
Probability of reversal, in writing, from appellate counsel.
Damages exposure: the brand's lost profits, not a reasonable royalty — 35 U.S.C. § 271(e)(4) permits damages only for commercial manufacture, use, or sale.
Enhanced damages and willfulness exposure.
Section 285 fee exposure.
Injunction, recall, and customer disruption risk.
Insurance review.
Board-level approval with a documented analysis.

Part 12 — Settlement

The entry date — the operative term.
Acceleration triggers: another generic's entry, an invalidity ruling, defined events.
Most-favored-entry provisions.
A license effective on the entry date.
Whether the brand may launch an authorized generic, and when — frequently the most valuable term to the generic.
Dismissal terms and treatment of the certifications.

Antitrust structuring — before signing, not after:

Antitrust counsel involved in structuring.
Litigation-cost justification documented with actual budget figures.
Independent value documented for any side deal — supply agreement, license, collaboration.
Recognize a no-authorized-generic commitment is consideration and analyze it as such.
Apply the rule-of-reason framework of FTC v. Actavis, Inc., 570 U.S. 136 (2013).
File the required reports with the FTC and DOJ.
Confirm the settlement does not trigger a 180-day exclusivity forfeiture event.

Part 13 — The 505(b)(2) variant

Confirm whether the application relies on FDA findings for a previously approved drug — if so, the same certification obligations apply under 21 U.S.C. § 355.
Recognize: same notice, same § 271(e)(2) act of infringement, same 30-month stay.
Recognize: no 180-day exclusivity, no automatic substitutability, but the applicant may earn its own exclusivities and patents.
Choose the reference product deliberately — different references carry different patent listings.
Choose the indications sought deliberately — fewer indications may avoid method-of-use patents entirely.
Bring patent counsel in at the formulation stage, not at filing.