Litigation Details for Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc. (D. Del. 2015)

Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc. (D. Del. 2015)

Docket		Date Filed	2015-11-06
Court	District Court, D. Delaware	Date Terminated	2016-05-23
Cause	35:271 Patent Infringement	Assigned To	Gregory Moneta Sleet
Jury Demand	None	Referred To
Patents	8,288,434; 8,663,699
Link to Docket	External link to docket

Details for Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc. (D. Del. 2015)

Date Filed	Document No.	Description	Snippet	Link To Document
2015-11-06				External link to document
2015-11-05	1		United States Patent Nos. 8,288,434 (“the ’434 patent”) and 8,663,699 (“the ’699 patent”) arising under… THE PATENTS IN SUIT 8. The U.S. Patent and Trademark Office (“PTO…PTO”) issued the ’434 patent on October 16, 2012. The ’434 patent claims, inter alia, formulations of…. Dow is the assignee of the ’434 patent. A copy of the ’434 patent is attached hereto as Exhibit A. …. The PTO issued the ’699 patent on March 4, 2014. The ’699 patent claims, inter alia, methods of	External link to document
2015-11-05	4		the Commissioner of Patents and Trademarks for Patent/Trademark Number(s) 8,288,434 B2; 8,663,699 B2. (… 2015 23 May 2016 1:15-cv-01030 830 Patent None District Court, D. Delaware	External link to document

Dow Pharmaceutical Sciences v. Tolmar Patent Litigation: Aczone 7.5% Gel Case Summary

Last updated: August 21, 2026

Dow Pharmaceutical Sciences, Inc. defeated Tolmar, Inc.’s abbreviated new drug application challenge involving Aczone 7.5% dapsone gel. The dispute concerned U.S. Patent Nos. 9,125,910 and 9,192,644, which covered topical dapsone compositions and the formulation used in Aczone 7.5% Gel. The U.S. District Court for the District of Delaware upheld the asserted claims against invalidity challenges, and the Federal Circuit affirmed in 2018. [1], [2]

The case was filed as Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc., No. 1:15-cv-01030, in the District of Delaware. Tolmar’s ANDA certification created the Hatch-Waxman dispute. The principal commercial consequence was delayed generic entry for Aczone 7.5% Gel unless Tolmar prevailed, settled, or obtained a noninfringing approval path.

What drug and patents were involved in Dow v. Tolmar?

The litigation involved Aczone 7.5% Gel, a topical prescription product containing dapsone for acne vulgaris. Dow Pharmaceutical Sciences developed the product and was the patent owner or plaintiff asserting the relevant rights. Valeant Pharmaceuticals, later operating through Bausch Health, commercialized Aczone after acquiring Dow.

Item	Details
Branded product	Aczone 7.5% Gel
Active ingredient	Dapsone
Dosage form	Topical gel
Therapeutic use	Acne vulgaris
Plaintiff	Dow Pharmaceutical Sciences, Inc.
Defendant	Tolmar, Inc.
Court	U.S. District Court for the District of Delaware
District docket	No. 1:15-cv-01030
Federal Circuit decision	901 F.3d 1363 (Fed. Cir. 2018)
Patents asserted	U.S. Patent Nos. 9,125,910 and 9,192,644
Litigation pathway	Hatch-Waxman ANDA litigation

The patents addressed a dapsone gel formulation designed to deliver 7.5% dapsone in a topical vehicle with specific formulation characteristics. The case was not a biologic patent dispute. Biosimilar law and the Biologics Price Competition and Innovation Act therefore did not apply.

What patents protected Aczone 7.5% Gel?

The central patent estate consisted of U.S. Patent Nos. 9,125,910 and 9,192,644. The asserted claims covered composition and formulation limitations associated with the dapsone gel product.

U.S. Patent No. 9,125,910

The ’910 patent concerned topical pharmaceutical compositions containing dapsone. The patent was directed to a gel formulation in which the active ingredient was combined with excipients and a topical vehicle designed for dermatological administration.

Tolmar challenged the patent on validity grounds, including obviousness. The district court rejected those challenges after evaluating the prior art, formulation differences, the motivation to combine references, and the expectation that a skilled artisan would have had regarding the claimed composition.

U.S. Patent No. 9,192,644

The ’644 patent was another dapsone composition patent asserted against Tolmar’s proposed generic product. The patent protected additional formulation and compositional limitations associated with the 7.5% dapsone gel.

The patents should be analyzed as a formulation-focused estate rather than as broad protection for dapsone itself. Dapsone was an established active pharmaceutical ingredient. The commercial value came from the specific topical delivery system, concentration, excipient combination, and product performance.

What was Tolmar’s ANDA challenge?

Tolmar filed an ANDA seeking FDA approval to market a generic version of Aczone 7.5% Gel. The ANDA triggered Paragraph IV certifications against the patents listed for Aczone.

A Paragraph IV certification states that a listed patent is invalid, unenforceable, or will not be infringed by the proposed generic product. When the brand company sues within the statutory period, FDA approval is generally stayed for up to 30 months, subject to statutory exceptions and court events.

Dow sued Tolmar under the Hatch-Waxman framework. The case placed infringement and validity before the district court before Tolmar could commercially launch the proposed product.

The public decisions focus primarily on patent validity and the technical formulation dispute. The case was not an ordinary post-launch patent infringement action because Tolmar’s product was an ANDA product and the litigation arose from the Paragraph IV process.

How did the court decide Dow v. Tolmar?

The district court ruled in Dow’s favor on the principal validity issues. The Federal Circuit affirmed the judgment in Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc., 901 F.3d 1363 (Fed. Cir. 2018). [2]

The Federal Circuit’s analysis addressed whether the asserted claims would have been obvious in view of the prior art. The court considered:

• The state of the art for topical dapsone formulations.
• The differences between the prior-art compositions and the claimed 7.5% dapsone gel.
• Whether a skilled artisan would have been motivated to make the claimed formulation.
• Whether the artisan would have had a reasonable expectation of success.
• Evidence concerning the formulation’s performance and development history.

The court did not treat the existence of earlier dapsone topical products as sufficient by itself to establish obviousness. The relevant question was whether the specific claimed formulation would have been predictable from the prior art.

The decision is important because it illustrates the limits of relying on a known active ingredient and a known therapeutic use to invalidate a later formulation patent. The asserted claims survived because the combination of concentration, vehicle, excipients, and formulation performance was not shown to be an obvious modification.

Why did Dow prevail on obviousness?

Dow’s successful position rested on the distinction between the known properties of dapsone and the claimed properties of the finished topical gel.

A generic applicant challenging a formulation patent must establish more than the following propositions:

1. Dapsone was already known.
2. Dapsone had already been used for dermatological conditions.
3. Topical gels were conventional dosage forms.
4. A skilled artisan could have attempted a similar product.

The analysis requires proof that the claimed formulation would have been selected with a reasonable expectation of success. The Federal Circuit’s decision treated formulation development as technically significant because changes in concentration, vehicle, excipients, solubility, stability, skin delivery, tolerability, and product performance can materially affect the result.

The decision also limited the use of hindsight. Once a successful formulation is known, it may appear straightforward to reconstruct. Patent law requires the obviousness analysis to be performed from the perspective of the skilled artisan before the invention, not with knowledge of the claimed product.

What was the litigation timeline?

Date	Event
September 2015	U.S. Patent No. 9,125,910 issued
November 2015	U.S. Patent No. 9,192,644 issued
2015	Dow filed the Delaware Hatch-Waxman action against Tolmar
2017	District court proceedings addressed claim construction, infringement, and validity
2018	Federal Circuit issued its decision at 901 F.3d 1363
Post-2018	The Federal Circuit judgment preserved Dow’s favorable result against Tolmar’s validity challenge

The district court docket is commonly cited as No. 1:15-cv-01030. The Federal Circuit appeal provides the controlling appellate analysis for the asserted patents and the obviousness dispute.

What was the Orange Book status of Aczone?

Aczone is an FDA-approved small-molecule drug product, not a biologic. Its patent and exclusivity analysis therefore falls under the Hatch-Waxman framework.

FDA Orange Book analysis for Aczone should distinguish among:

• Product patents covering the marketed dapsone gel.
• Method-of-use patents, if listed for the approved indication.
• Patent expiration dates.
• Pediatric exclusivity, if any.
• Regulatory exclusivity associated with the original approval or later supplement.
• Later generic approvals that may have changed the practical scope of the estate.

The Dow v. Tolmar case involved formulation patents rather than a pure method-of-use dispute. The asserted patents were valuable because they targeted the commercial product’s composition and delivery system. A generic applicant could potentially avoid a formulation patent by modifying excipients, concentration, vehicle, or other composition parameters, but those changes would need to remain acceptable under FDA’s ANDA requirements and equivalent enough to the reference product.

Patent listings and expiration dates can change in commercial significance after litigation. A patent may remain listed while a later-approved generic product is approved based on a different certification, settlement, noninfringement position, or alternative formulation.

When does Aczone lose patent exclusivity?

The relevant patent exclusivity date depends on the particular patent and any applicable patent-term adjustment, terminal disclaimer, pediatric extension, or later Orange Book listing.

The ’910 and ’644 patents were issued in 2015 and were directed to formulation technology rather than the original discovery of dapsone. Their effective patent terms were therefore tied to their underlying priority and filing history, not simply to their issue dates.

For commercial diligence, the operative date should be taken from the FDA Orange Book and the USPTO patent records together. The analysis should not assume that the latest-issued patent necessarily provides the longest enforceable exclusivity. Patent-term adjustment and terminal disclaimers can alter the expiration relationship between related patents.

The Federal Circuit decision established that the asserted claims survived the Tolmar challenge. It did not, by itself, establish a permanent market exclusion independent of patent expiration, settlement terms, FDA approval status, or later litigation.

Did Dow assert formulation patents or method-of-use patents?

The Dow v. Tolmar dispute centered on formulation patents. The claims covered dapsone topical compositions and the characteristics of the gel formulation.

Protection category	Role in Dow v. Tolmar
Active ingredient patent	Not the central issue; dapsone was known
Composition patent	Central
Formulation patent	Central
Method-of-use patent	Not the principal basis of the reported appeal
Manufacturing patent	Not the principal basis of the reported appeal
Device or delivery-system patent	Not the principal basis of the reported appeal

This distinction affects generic-entry risk. A method-of-use patent may be addressed through a section viii statement or labeling carve-out if the generic omits the patented use. A composition patent generally presents a more direct barrier because the generic product itself may practice the claimed formulation.

How strong was Dow’s patent estate?

The litigation record indicates that the asserted estate had meaningful strength against the specific Tolmar challenge. The most important evidence is the Federal Circuit’s affirmance of the district court’s nonobviousness determination.

The estate’s strengths were:

• Claims directed to the commercial formulation rather than only to dapsone.
• A favorable district court judgment.
• Federal Circuit affirmance.
• Formulation-specific limitations that made a simple active-ingredient prior-art argument insufficient.
• Potential Orange Book leverage in an ANDA proceeding.

The estate also had structural limitations:

• Dapsone was a known compound.
• Topical dermatological products were an established dosage form.
• Formulation claims are sensitive to claim construction and technical prior art.
• A generic manufacturer may pursue a design-around formulation.
• Patent protection is geographically limited and does not prevent non-U.S. competition outside the relevant rights.
• Patent strength does not eliminate FDA, manufacturing, substitution, reimbursement, or commercial-launch risks.

The strongest litigation value was concentrated in the formulation claims that mapped onto Aczone 7.5% Gel. Broader claims would have faced greater exposure to prior-art and design-around arguments.

Which companies challenged or competed with Aczone?

Tolmar was the defendant in the identified action. Other generic companies may have pursued Aczone-related approvals or market opportunities, but the existence of an ANDA or later approval does not establish that a company was a party to this case.

The competitive landscape includes:

• Dow Pharmaceutical Sciences and its successor commercial interests.
• Valeant Pharmaceuticals and Bausch Health as historical commercial stakeholders.
• Tolmar as the litigated ANDA applicant.
• Other dermatology companies developing topical acne products.
• Generic manufacturers pursuing dapsone gel approval or alternative topical formulations.
• Competing acne therapies containing benzoyl peroxide, retinoids, antibiotics, or other active ingredients.

Aczone competes in a crowded acne market. Its patent value was therefore tied to the ability to preserve price, formulary access, physician prescribing, and market share for the branded formulation before generic substitution.

What generic-entry risks existed after the decision?

The Federal Circuit victory reduced the immediate risk from Tolmar’s specific Paragraph IV challenge, but it did not remove all generic-entry scenarios.

At-risk launch

Tolmar could have launched before patent expiration while accepting infringement exposure. That strategy would have created potential damages and injunction risk. The reported appellate outcome made an at-risk launch less attractive.

Settlement and licensed entry

Dow, its successors, and Tolmar could have resolved the case through a settlement providing a permitted entry date, license, supply arrangement, or other commercial terms. The public appellate decision does not establish the terms of any confidential settlement.

Design-around product

Tolmar or another manufacturer could seek approval for a formulation that avoids one or more claim limitations. The commercial feasibility would depend on whether the alternative formulation was pharmaceutically acceptable, sufficiently equivalent for ANDA purposes, and commercially competitive.

Later patent challenges

A later generic applicant could challenge a different patent, contest listing status, rely on a different certification, or attack the estate based on new prior art or changed claim scope.

Non-patent erosion

Even without an approved generic, Aczone could face erosion from competing acne products, payer restrictions, authorized distribution arrangements, channel changes, and therapeutic substitution.

Was there biosimilar risk?

No. Aczone contains dapsone, a small-molecule active ingredient, and is approved under the drug provisions of the Federal Food, Drug, and Cosmetic Act. The relevant competitive pathway is an ANDA, not a biosimilar application under the BPCIA.

The principal regulatory risk was generic substitution after ANDA approval, subject to patent certifications, exclusivity, labeling, and state substitution laws.

Did the case involve a licensing deal or settlement agreement?

The reported appellate opinion does not disclose a licensing transaction or settlement agreement that can be treated as a public term of the case. Confidential Hatch-Waxman settlements are common, but their existence and entry dates must be established from operative court filings, FDA approval records, or regulatory disclosures rather than inferred from the appellate merits decision.

The Federal Circuit decision is therefore best treated as a merits ruling on patent validity, not as evidence of a publicly disclosed license.

What manufacturing and intellectual-property barriers remained?

The formulation patents created an IP barrier for products practicing the claimed dapsone gel composition. Manufacturing also presented technical constraints because topical dapsone products require control over:

• Uniform drug distribution.
• Product stability.
• Viscosity and rheology.
• Skin delivery.
• Preservative performance.
• Microbial quality.
• Container and closure compatibility.
• Scale-up reproducibility.

A manufacturer could avoid literal infringement by changing a claimed component, but that change could affect product quality or FDA comparability. The doctrine of equivalents could create additional litigation exposure, although its application would depend on the specific claim limitation and prosecution history.

What was the revenue exposure from the Tolmar case?

The public opinions do not provide a case-specific revenue forecast. The commercial exposure was the U.S. Aczone 7.5% Gel franchise, including the risk that generic entry would reduce net sales through price compression and pharmacy substitution.

Revenue impact would depend on:

• The actual generic entry date.
• Number of approved generic competitors.
• Whether the generic was therapeutically and pharmaceutically substitutable.
• Payer coverage and formulary placement.
• Brand pricing and rebate strategy.
• Patient demand and prescriber loyalty.
• The remaining life of any listed patents and regulatory exclusivity.

The strongest economic value of the Dow patents was the ability to delay or condition generic competition for the marketed formulation.

Key Takeaways

• Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc., No. 1:15-cv-01030, was a Hatch-Waxman case involving Aczone 7.5% dapsone gel.
• The asserted patents were U.S. Patent Nos. 9,125,910 and 9,192,644.
• The patents focused on topical dapsone composition and formulation technology.
• The district court rejected Tolmar’s principal invalidity challenge.
• The Federal Circuit affirmed Dow’s favorable result in 901 F.3d 1363 (Fed. Cir. 2018).
• The decision limited an obviousness theory based only on known dapsone, known topical therapy, and conventional gel technology.
• The case involved small-molecule generic risk, not biosimilar risk.
• Formulation patents provided the principal barrier; method-of-use and manufacturing patents were not the central appellate issues.
• The decision reduced Tolmar’s immediate launch leverage but did not eliminate design-around, settlement, later-challenge, or post-expiration generic-entry scenarios.
• Orange Book status, current patent-term calculations, and later FDA approvals remain necessary for a current exclusivity assessment.

FAQs

What was the active ingredient in the Dow v. Tolmar litigation?

The active ingredient was dapsone, formulated as a 7.5% topical gel for acne vulgaris.

Did Dow v. Tolmar concern Aczone 5% or Aczone 7.5%?

The litigation concerned Aczone 7.5% Gel and the formulation patents associated with that product.

What Federal Circuit case number corresponds to Dow v. Tolmar?

The Federal Circuit decision is reported at 901 F.3d 1363 (Fed. Cir. 2018).

Could a generic company avoid Dow’s patents by changing the gel vehicle?

Potentially, but the alternative product would need to avoid the asserted claim limitations and satisfy FDA approval requirements. A formulation change could also create new technical and equivalence issues.

Was Tolmar authorized to launch a generic Aczone product after the Federal Circuit decision?

The appellate decision confirms the patent-validity result but does not itself establish a later launch date, license, or settlement term.

References

1. U.S. District Court for the District of Delaware. (2015-2018). Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc., No. 1:15-cv-01030.

2. United States Court of Appeals for the Federal Circuit. (2018). Dow Pharmaceutical Sciences, Inc. v. Tolmar, Inc., 901 F.3d 1363.

3. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.

4. U.S. Patent and Trademark Office. (2015). U.S. Patent No. 9,125,910, topical compositions containing dapsone.

5. U.S. Patent and Trademark Office. (2015). U.S. Patent No. 9,192,644, topical compositions containing dapsone.