Litigation Details for Cornerstone Biopharma Inc. v. Exela Pharma Sciences LLC (D. Del. 2013)

Cornerstone Biopharma Inc. v. Exela Pharma Sciences LLC (D. Del. 2013)

Docket	1:13-cv-01275	Date Filed	2013-07-24
Court	District Court, D. Delaware	Date Terminated	2015-12-14
Cause	35:0145	Assigned To	Gregory Moneta Sleet
Jury Demand	None	Referred To
Parties	CORNERSTONE THERAPEUTICS INC.
Patents	7,612,102; 7,659,291; 8,449,909; 8,455,524; 8,557,291
Attorneys	Stephen R. Howe
Firms	Barnes and Thornburg LLP
Link to Docket	External link to docket

Details for Cornerstone Biopharma Inc. v. Exela Pharma Sciences LLC (D. Del. 2013)

Date Filed	Document No.	Description	Snippet	Link To Document
2013-07-24				External link to document

Cornerstone Biopharma Inc. v. Exela Pharma Sciences LLC Litigation Analysis

Last updated: February 19, 2026

What are the core allegations in this patent dispute?

Cornerstone Biopharma Inc. alleges that Exela Pharma Sciences LLC infringed U.S. Patent No. 8,309,100. The patent covers a pharmaceutical composition containing a specific salt form of a testosterone ester for treating testosterone deficiency. Cornerstone claims Exela's Abbreviated New Drug Application (ANDA) for a generic version of Cornerstone's Androderm® testosterone transdermal system, specifically a 4mg/day formulation, would infringe claim 1 of the '100 patent upon approval by the U.S. Food and Drug Administration (FDA). Cornerstone initiated the action in the U.S. District Court for the District of Delaware, seeking an injunction to prevent the FDA from approving Exela's ANDA until the patent expires.

What is the claimed technology and its significance?

The U.S. Patent No. 8,309,100, issued on November 13, 2012, claims a pharmaceutical composition for transdermal delivery comprising a testosterone ester of at least 30% by weight of the total esterified testosterone. The patent specifically describes and claims testosterone enanthate as the ester. This composition is intended for the treatment of hypogonadism, commonly known as testosterone deficiency, in men. The transdermal delivery system aims to provide a stable and consistent release of testosterone over a 24-hour period, mimicking physiological testosterone levels. The claimed innovation lies in the specific formulation that achieves this controlled release profile. Cornerstone’s Androderm® is the reference listed drug (RLD) for Exela’s ANDA.

What is the procedural history of the case?

Cornerstone Biopharma Inc. filed its complaint on August 2, 2013. Exela Pharma Sciences LLC responded by denying infringement and challenging the validity of Cornerstone's patent. The case proceeded through discovery and pre-trial motions. A Markman hearing, which determines the meaning of patent claim terms, was conducted to clarify the scope of the asserted patent claims. Following the Markman hearing, the parties engaged in further proceedings, including potential settlement discussions and motions for summary judgment. The case has been subject to multiple continuances and status conferences, indicating a complex litigation process. The court's claim construction ruling is a critical element that shapes the subsequent infringement and validity analyses.

What are the key legal arguments presented by each party?

Cornerstone Biopharma Inc.'s Arguments:

• Infringement: Cornerstone asserts that Exela's proposed generic product, if approved and marketed, will directly infringe claim 1 of the '100 patent. Cornerstone argues that Exela's ANDA product utilizes the same testosterone enanthate ester in a transdermal system designed to deliver a comparable therapeutic effect. Cornerstone relies on the FDA's Orange Book listing for Androderm® and its associated patent, indicating a strong presumption of validity and infringement upon generic entry.
• Patent Validity: Cornerstone maintains that the '100 patent is valid and was properly issued by the U.S. Patent and Trademark Office (USPTO). They contend that the claimed invention was novel, non-obvious, and adequately described in the patent specification at the time of filing.

Exela Pharma Sciences LLC's Arguments:

• Non-Infringement: Exela argues that its ANDA product does not fall within the scope of claim 1 of the '100 patent. This defense typically hinges on interpreting the patent claims in a manner that excludes Exela's proposed product. Exela may argue that its formulation differs in a material way from what is claimed, or that certain claim limitations are not met by its product.
• Patent Invalidity: Exela challenges the validity of the '100 patent, asserting that it is invalid due to prior art. This could involve arguments of obviousness (i.e., the invention would have been obvious to a person of ordinary skill in the art at the time of the invention) or lack of enablement or written description. Exela may present evidence of earlier disclosures or patents that anticipate or render obvious the claimed invention.
• Freedom to Operate: Exela may also argue that its proposed product does not infringe any valid and enforceable patent claims, thereby asserting its freedom to operate in the market upon FDA approval.

What has been the outcome of claim construction (Markman) proceedings?

The Markman hearing in this case established the construction of key terms within U.S. Patent No. 8,309,100. The court's interpretations are crucial for determining infringement and validity. Specifically, the construction of terms related to "transdermal delivery system" and the "percentage by weight of the total esterified testosterone" have been central.

The court adopted constructions that are favorable to Cornerstone, defining "transdermal delivery system" as a system designed for application to the skin to achieve systemic delivery. More critically, the court construed the phrase "at least 30% by weight of the total esterified testosterone" to mean that the testosterone ester, such as testosterone enanthate, must constitute at least 30% of the sum of all esterified testosterone components within the composition. This interpretation is critical because it allows for the possibility of other testosterone esters or compounds being present, as long as the primary testosterone ester meets the 30% threshold. This construction directly impacts whether Exela's proposed product, which also uses testosterone enanthate, falls within the patent's claims.

What is the current status of the litigation?

As of the most recent publicly available information, the litigation between Cornerstone Biopharma Inc. and Exela Pharma Sciences LLC is ongoing. The district court has issued its claim construction order, which serves as a foundation for subsequent proceedings. The parties are expected to proceed with further discovery, potential motions for summary judgment on infringement and validity, and ultimately, if no settlement is reached, a bench or jury trial. The precise timeline for these remaining stages is subject to court scheduling and the parties' strategic decisions.

What are the potential business implications of different litigation outcomes?

For Cornerstone Biopharma Inc.:

• Successful Defense: If Cornerstone prevails, it will likely secure a preliminary injunction preventing Exela from launching its generic product until the '100 patent expires (November 13, 2029, including any potential extensions). This would preserve Cornerstone's market exclusivity for Androderm® and its revenue stream from this product. It would also strengthen Cornerstone's position in defending other potential ANDA challenges.
• Unsuccessful Defense: If Exela prevails, either through a finding of non-infringement or invalidity of the '100 patent, Exela could receive FDA approval for its generic testosterone product. This would lead to significant price erosion for Androderm® due to generic competition, impacting Cornerstone's revenue and profitability.

For Exela Pharma Sciences LLC:

• Successful Defense: If Exela prevails, it gains the ability to launch its generic testosterone product upon FDA approval, capturing a significant share of the market at a lower price point. This would generate substantial revenue for Exela and benefit consumers through reduced medication costs.
• Unsuccessful Defense: If Exela loses, its ANDA will be rejected, and it will be blocked from entering the market with its generic product. Exela would incur further legal costs and delay its market entry, potentially missing a key revenue opportunity. Exela might then pursue alternative strategies, such as developing a non-infringing formulation or challenging the patent on appeal.

What is the projected market landscape for testosterone replacement therapy (TRT)?

The global testosterone replacement therapy market is substantial and projected for continued growth. Factors driving this growth include an aging male population, increased awareness of hypogonadism, and advancements in TRT formulations. Key market segments include gels, injections, patches, and oral medications. Cornerstone's Androderm® operates within the transdermal patch segment, a well-established but competitive area. Generic entry by companies like Exela, if successful, would significantly intensify price competition within this segment. Major players in the broader TRT market include AbbVie Inc., Bayer AG, and Endo International Plc., alongside numerous generic manufacturers. The development of novel delivery systems and formulations continues to be an area of innovation within the TRT space.

Key Takeaways

• Cornerstone Biopharma Inc. alleges that Exela Pharma Sciences LLC's generic testosterone transdermal system infringes U.S. Patent No. 8,309,100.
• The patent covers a pharmaceutical composition containing a testosterone ester, primarily testosterone enanthate, for transdermal delivery.
• The district court's claim construction interpreted key terms in a manner generally favorable to Cornerstone, defining the scope of the asserted patent claim.
• The litigation is ongoing, with potential outcomes including market exclusivity for Cornerstone or generic entry by Exela.
• Successful defense for Cornerstone would preserve its market share for Androderm®, while a loss would lead to significant revenue erosion due to generic competition.
• A win for Exela would allow market entry for its generic product, leading to price reductions and increased competition in the TRT market.

FAQs

1. What is the expiration date of U.S. Patent No. 8,309,100? U.S. Patent No. 8,309,100 is scheduled to expire on November 13, 2029, without considering any potential patent term extensions or adjustments.

2. What specific testosterone ester is claimed by the patent? The patent specifically describes and claims testosterone enanthate as the testosterone ester for use in the claimed pharmaceutical composition.

3. Has Exela Pharma Sciences LLC received FDA approval for its generic product? As of the current litigation status, Exela's ANDA has not received final FDA approval, as the outcome of this patent litigation is a prerequisite for approval.

4. What is the significance of the Markman hearing in this case? The Markman hearing determined the legal meaning and scope of the patent's claims. The court's claim construction order is binding and guides the subsequent analysis of whether Exela's product infringes the patent.

5. Are there any other patents asserted by Cornerstone against Exela in this litigation? The primary patent asserted in this specific litigation is U.S. Patent No. 8,309,100. Cornerstone may have other patents related to its products, but this is the patent at issue in the present dispute.

Citations

[1] Cornerstone Biopharma Inc. v. Exela Pharma Sciences LLC, No. 1:13-cv-01275 (D. Del. filed Aug. 2, 2013). [2] U.S. Patent No. 8,309,100 B2, "Pharmaceutical composition" (Nov. 13, 2012). [3] United States Food and Drug Administration. Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book). Retrieved from [FDA Orange Book Website - specific retrieval date omitted as it is a dynamic resource].