Harmony Biosciences Management Inc et al. v. AET Pharma US Inc et al.

This patent infringement lawsuit is a key battleground in the pharmaceutical industry, pitting branded drug manufacturer Harmony Biosciences against a coalition of generic drug makers led by AET Pharma and Sandoz. The plaintiffs are Harmony Biosciences Management Inc., a commercial-stage pharmaceutical company focused on rare neurological diseases, and Novitium Pharma LLC, a generic pharmaceutical developer. The defendants are prominent players in the generic pharmaceutical space, including AET Pharma US Inc., its German parent Alfred E Tiefenbacher, Indian affiliate AET Laboratories Private Ltd, and various entities of Sandoz, a global leader in generic and biosimilar medicines. The dispute centers on the defendants' attempt to market a generic version of Harmony's sole commercial product, WAKIX® (pitolisant hydrochloride), a blockbuster drug for treating excessive daytime sleepiness and cataplexy in narcolepsy patients.

The lawsuit, filed in the U.S. District Court for the District of Delaware, alleges that the defendants' proposed generic drugs infringe U.S. Patent No. 11,623,920. This patent, titled "Process for preparing pitolisant hydrochloride and solid-state forms thereof," covers methods of manufacturing the active pharmaceutical ingredient in WAKIX®. This case is a typical Hatch-Waxman litigation, triggered by the defendants' filing of an Abbreviated New Drug Application (ANDA) with the FDA, which is a statutory act of patent infringement. By filing suit within 45 days of receiving the defendants' notice, Harmony triggered an automatic 30-month stay on the FDA's ability to approve the generic competitor, providing time for the patent dispute to be litigated. The choice of the Delaware District Court is significant, as it is a premier venue for patent litigation, particularly for complex pharmaceutical cases under the Hatch-Waxman Act, known for its experienced judiciary in handling such matters.

This case is highly notable as it represents a critical defense of Harmony's main revenue source. WAKIX® is central to Harmony's financial success, and protecting its market exclusivity is a top corporate priority. The litigation against AET and Sandoz is part of a broader legal strategy by Harmony to fend off generic competition; the company has previously engaged in similar litigation and successfully settled with another generic manufacturer, Lupin Limited, delaying their market entry until at least 2030. The outcome of this case will have substantial market implications, determining when lower-cost generic versions of WAKIX® become available to patients and directly impacting Harmony's future revenues and stock performance.

As of 2026-05-01, the patent infringement litigation Harmony Biosciences Management Inc et al. v. AET Pharma US Inc et al., Case No. 1:26-cv-00453, is in its earliest procedural stages. Having been filed very recently, there have been no substantive rulings, and the docket consists primarily of the initial complaint.

Key Developments (Chronological)

Filing of the Complaint (2026-04-20)

• Event: Harmony Biosciences and co-plaintiff Novitium Pharma LLC filed a patent infringement lawsuit against AET Pharma, Sandoz, and their related entities in the U.S. District Court for the District of Delaware.
• Allegation: The complaint alleges that the defendants infringed U.S. Patent No. 11,623,920 (the '920 patent), titled "Process for preparing pitolisant hydrochloride and solid-state forms thereof," by filing an Abbreviated New Drug Application (ANDA) with the U.S. Food and Drug Administration (FDA). This filing seeks approval to market and sell generic versions of Harmony's WAKIX® (pitolisant hydrochloride) tablets before the expiration of the '920 patent.
• Statutory Framework: The lawsuit was filed under the provisions of the Hatch-Waxman Act, where the submission of an ANDA is a statutory act of patent infringement (35 U.S.C. § 271(e)(2)). By filing the suit within the statutory 45-day window, Harmony triggered an automatic 30-month stay of FDA approval for the defendants' generic products, pending the outcome of the litigation.
• Strategic Significance: The '920 patent is noted as covering not just specific crystalline forms but also amorphous formulations of pitolisant, potentially extending intellectual property protection for WAKIX® to 2042. The lawsuit is seen by market analysts as a "significant positive" for Harmony, potentially removing a major concern about generic competition entering the market before 2030.

Initial Pleadings & Current Posture (Present)

• Status: As of early May 2026, the case remains in the initial pleading stage. The defendants have not yet filed an Answer and any Counterclaims in response to the complaint. Under the Federal Rules of Civil Procedure, an answer is typically due 21 days after service of the complaint, a deadline that has not yet passed.
• Next Steps: The litigation is expected to follow the typical path for a complex Hatch-Waxman case. Future milestones will include the defendants' Answer, a scheduling conference, the exchange of infringement and invalidity contentions, fact and expert discovery, a claim construction (Markman) hearing, and potentially summary judgment motions before any trial.
• Outcome: The case is active and has not been settled, dismissed, or adjudicated.

Parallel PTAB Proceedings

As of 2026-05-01, no Inter Partes Review (IPR) or Post-Grant Review (PGR) petitions filed by AET or Sandoz against the '920 patent have been identified. It is important to distinguish this from Harmony's broader patent defense strategy:

• On July 31, 2024, the Patent Trial and Appeal Board (PTAB) declined for a second time to institute an Ex Parte Reexamination of a different Harmony patent related to a polymorph form of pitolisant hydrochloride, strengthening that element of its patent portfolio.

This specific litigation concerning the '920 patent is new, and defendants have up to one year after being served with the complaint to file an IPR petition challenging the patent's validity before the PTAB.

Plaintiffs' Counsel of Record

As of May 3, 2026, counsel for the plaintiffs, Harmony Biosciences Management Inc. and Novitium Pharma LLC, have been identified from the initial complaint filed on April 20, 2026.

Based on the filing (D.I. 1), the legal team for the plaintiffs includes attorneys from Saul Ewing LLP, serving as local counsel in Delaware, and Sterne, Kessler, Goldstein & Fox P.L.L.C., known for its expertise in intellectual property law, serving as lead counsel.

Sterne, Kessler, Goldstein & Fox P.L.L.C. (Lead Counsel)

• J.C. Rozendaal (Lead Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Rozendaal is a seasoned patent trial lawyer with extensive experience in pharmaceutical litigation, including Hatch-Waxman cases.

• William H. Milliken (Of Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Milliken focuses on patent litigation and has represented clients in the pharmaceutical and biotechnology industries in district courts and before the PTAB.

• Paul A. Ainsworth (Of Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Ainsworth's practice concentrates on patent litigation, particularly within the life sciences and pharmaceutical sectors.

• Adrian A. Zelek (Of Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Zelek specializes in intellectual property law with a focus on litigating patent disputes for pharmaceutical and biotechnology clients.

Saul Ewing LLP (Local Counsel)

• Denise S. Kraft (Local Counsel)
  • Firm: Saul Ewing LLP, Wilmington, Delaware.
  • Note: Kraft is a partner in the firm's Wilmington office and frequently serves as Delaware counsel in high-stakes patent litigation, particularly in the pharmaceutical industry.

Defendants' Counsel Has Not Yet Appeared

As of May 3, 2026, counsel for the defendants AET Pharma US Inc., Sandoz AG, Alfred E Tiefenbacher GMBH & Co KG, Sandoz Private Ltd., and AET Laboratories Private Ltd. have not yet filed a notice of appearance or any responsive pleadings in this case.

The lawsuit was filed on April 20, 2026, and summons were issued to the various domestic and international defendants on April 21, 2026. The deadlines for defendants to respond to the complaint have not yet passed, particularly for the foreign entities which may have extended response times under federal rules and international treaties.

Consequently, no attorneys are officially on record for the defense. The public docket for Case No. 1:26-cv-00453 in the U.S. District Court for the District of Delaware does not yet contain any documents identifying the law firms or specific lawyers who will be representing the defendant group.

While it is common for major generic pharmaceutical companies like Sandoz and specialized firms like AET to retain counsel with deep experience in Hatch-Waxman litigation in Delaware, any speculation as to which firms will appear would be premature. Firms known for representing generic drug manufacturers in such cases include Perkins Coie LLP, Knobbe Martens, and others, but their involvement in this specific matter is not confirmed. The first official identification of defense counsel will occur when they file their first document with the court, which will likely be either a notice of appearance or an answer to the complaint.