1.) Recent P-IV filings (Maralixibat Chloride, Livmarli) and 2.) GSK vs Pfizer- A case related to mRNA vaccine technology.
Contents
Recent P-IV filings
General information
Ken Paxton files lawsuit against drug companies accused of hiding information on Plavix
Depo-Provera Litigation Now Includes Over 2,000 Brain Tumor Lawsuits Brought by Women
Intellectual Property
GSK vs Pfizer
Recent P-IV filings
We follow P-IV filings on the FDA website. The recent update was on 11 November 2025. ANDA with P-IV filed recently related to Maralixibat Chloride. A recent Paragraph IV (P-IV) certification filing related to Maralixibat Chloride, (Livmarli), an ileal bile acid transporter (IBAT) inhibitor, was first approved by the FDA in September 2021 for the treatment of cholestatic pruritus in patients with Alagille syndrome (ALGS). Four ANDAs were filed for 9.5 MG, and three ANDAs were filed for 19 MG with P-IV certification. As per public domain information, one of the ANDA filers is Sandoz. The OB listed patents are as follows.
Maralixibat is an old molecule. Maralixibat was reportedly first patented by scientists at Searle in 1994 (Searle later became part of Pharmacia, which later became Pfizer). It was initially developed for a different use, the treatment of hypercholesterolemia (high cholesterol). The rights to the drug changed hands several times (Pfizer to Lumena Pharmaceuticals to Shire), and its development focus shifted to rare cholestatic liver diseases, such as Alagille syndrome (ALGS). Mirum Pharmaceuticals eventually acquired the exclusive rights in 2018 and brought the molecule through final clinical development. Since this is an old molecule, no compound-protecting patents were listed in OB, and many ANDA filers are on the NCE-1 date. The potential litigation outcome will determine launch timelines. Here are the estimated timelines for the 30-month stay and a potential Federal Circuit (CAFC) ruling: 30-Month Stay Timeline The 30-month stay is triggered by the brand company (Mirum) filing a patent infringement lawsuit within 45 days of receiving the P-IV notice from the generic applicant (Sandoz). The stay begins on the latest date Mirum or the patent owner received the notice.
- P-IV Notice Receipt: Around November 17, 2025 (Reasonable assumption)
- 45-Day Deadline to File Suit: Around January 1, 2026. (Mirum has publicly stated its intent to sue, so a lawsuit is highly expected).
- Start of 30-Month Stay: Approximately November/December 2025.
- Expiration of 30-Month Stay: Approximately May/June 2028.
During this period, the FDA cannot grant final approval to the generic ANDA, protecting Mirum's market exclusivity. However, the stay terminates early if the district court rules that the patents are invalid or not infringed. Trial/District Court Judgment: Likely to occur between late 2027 and early 2028. In a few cases, the district court issues a judgment before the 30-month stay expires, which immediately terminates the stay and allows the FDA to approve the generic if the generic applicant wins. Potential CAFC Ruling Timeline The losing party almost always appeals the judgment from the District Court to the U.S. Court of Appeals for the Federal Circuit (CAFC), the specialised court for patent appeals.
- Appeal to CAFC Filed: Within 30 days of the District Court judgment (e.g., Early 2028/ 1Q 2028)
- CAFC Briefing and Oral Argument: Typically takes 18 to 24 months from the date of the notice of appeal.
- CAFC Ruling: Likely to occur by the middle of 2030 to the end of 2030.
The "At-Risk Launch" Scenario Suppose the 30-month stay expires (around May/June 2028) before the District Court issues its ruling. In that case, the FDA may legally grant final approval to the ANDA (provided all other regulatory requirements are met). The generic company could then choose to launch their product "at-risk," meaning it enters the market but remains liable for massive damages if the District Court or a subsequent CAFC ruling ultimately finds the patents valid and infringed. In summary, while the 30-month stay itself expires in mid-2028, the final legal resolution, particularly after a CAFC appeal, could extend the litigation process until 2030 or potentially 2031. There is a high likelihood that particles will settle for the launch dates between 2031 and 2035. Generally, this could be a few years earlier than the last expiring patent listed in OB. This understanding is based on the outcome of a few recent cases and has nothing to do with the specifics of Maralixibat Chloride ANDAs and their potential litigations. There are 4 DMF filers. Honour, Biophore, APICORE (Apicore LLC is a wholly-owned subsidiary of RK Pharma Inc ) and Zhejiang Hetero had imported innovator samples in both 9.5 mg and 19 mg strengths. A few of these companies, along with Sandoz, could have filed ANDAs on the NCE-1 date.
General information
Ken Paxton files lawsuit against drug companies accused of hiding information on Plavix
Attorney General Ken Paxton has launched a lawsuit against pharmaceutical giants Sanofi and Bristol-Myers Squibb, accusing them of failing to disclose critical information about their drug Plavix. The lawsuit alleges that the companies did not inform patient-consumers and their prescribing physicians that Plavix, whose generic form is clopidogrel bisulfate, was ineffective for many patients, particularly those who are Black, East Asian, and Pacific Islander. Plavix is designed to prevent heart attacks, strokes, and blood clots by preventing platelets in the blood from clumping together. News hereDepo-Provera Litigation Now Includes Over 2,000 Brain Tumor Lawsuits Brought by Women
As part of the process of preparing those claims, the plaintiffs must first show that it is scientifically feasible that Depo-Provera can cause the development of brain tumors, which is known as general causation. Late last month the parties asked for, and received, additional time to finish general causation disclosures and depositions, with motions challenging general causation expert testimony due by March 22, 2026. If the plaintiffs establish that there is sufficient evidence for a jury to find general causation between Depo-Provera and meningioma brain tumors, the litigation will proceed to the pilot trials. News hereIntellectual Property
GSK vs Pfizer
This write-up is a summary of a Memorandum Opinion and Order issued by the Special Master in the case of GlaxoSmithKline Biologicals SA, and GlaxoSmithKline LLC (Plaintiffs/GSK) versus Pfizer Inc., Pharmacia & Upjohn Co. LLC, BioNTech SE, BioNTech Manufacturing GmbH, and BioNTech US Inc. (Defendants), filed in the United States District Court for the District of Delaware. The Special Master, having considered the parties' letter briefing and arguments presented at a hearing on October 10, 2025, ruled as follows:- Plaintiffs' Motion (D.I. 120) is DENIED.
- Defendants' Motion (D.I. 121) is GRANTED IN PART and DENIED IN PART.
- Supervising discovery, particularly complex electronic discovery (ESI) disputes.
- Sorting through scientific and technical issues or evaluating "scientific facts".
- Conducting evidentiary hearings, taking witness testimony, and making recommended findings of fact or legal recommendations to the presiding judge.
- U.S. Patent No. 11,638,693 (the "'693 patent")
- U.S. Patent No. 11,638,694 (the "'694 patent")
- U.S. Patent No. 11,666,534 (the "'534 patent")
- U.S. Patent No. 11,766,401 (the "'401 patent")
- U.S. Patent No. 11,786,467 (the "'467 patent")
- GSK's Motion to Compel Supplementation of Invalidity Contentions (DENIED): GSK sought to limit Defendants to no more than 12 obviousness combinations per asserted claim, arguing their initial contentions asserting "many quintillion" possible combinations provided no meaningful notice. The Special Master denied this, finding Defendants' disclosures were adequate at this early stage given the large number of asserted 98 claims.
- Defendants' Motion to Compel Claim Narrowing and ESI Terms (GRANTED IN PART, DENIED IN PART):
- Claim Narrowing (GRANTED IN PART): Defendants sought to reduce GSK's asserted claims from 98 to 50. The Special Master partially granted this, ordering GSK to narrow claims to no more than 80 within 14 days. In turn, Defendants must then narrow their obviousness combinations to no more than 24 per asserted claim.
- ESI Search Terms (DENIED): Defendants sought to compel GSK to propose up to 10 additional search terms immediately. The Special Master denied this, finding GSK was not unreasonable in waiting to propose terms until after receiving Defendants' internal documents.
