US 11839689

A technical analysis of U.S. Patent 11,839,689 reveals it pertains to specific formulations of the prostate cancer drug enzalutamide, designed to improve its solubility and absorption. The patent is currently active and has been asserted in recent litigation.

Patent Summary:

• Title: Formulations of enzalutamide
• Assignee: Astellas Pharma Inc. and Medivation Prostate Therapeutics LLC
• Inventors: Douglas Alan Lorenz, Sanjay Konagurthu, Randy J. Wald, Jason A. Everett, Sheila Matz, Yuuki Takaishi, Toshiro Sakai, Ryousuke Irie, Shinsuke Oba, Hiroyasu Toyota, Koji Nishimura, and Atsushi Kanbayashi.
• Filing Date: November 11, 2022
• Issue Date: December 12, 2023
• Abstract: The patent describes solid formulations of enzalutamide and their use in treating hyperproliferative disorders. The disclosure focuses on creating a solid dispersion of enzalutamide to enhance its solubility and absorption, thereby improving its effectiveness and allowing for more convenient dosing.

Plain-Language Overview of Independent Claims:

This patent contains several independent claims, which are the broadest statements of the invention. In essence, they protect different facets of the enzalutamide formulation.

• Claim 1: This claim protects a solid pharmaceutical composition, such as a tablet, that contains a specific amount of enzalutamide (around 160 mg). The key aspect is that the enzalutamide is in an amorphous (non-crystalline) state, dispersed within a specific polymer known as hydroxypropylmethylcellulose acetate succinate (HPMCAS). This formulation must also include a disintegrant, an agent that helps the tablet break apart, at a concentration of 6% to 10% by weight.

• Claim 8: This claim is directed at a method of treating prostate cancer. It covers the act of administering the pharmaceutical composition described in Claim 1 to a patient in need. This protects the medical use of the specific enzalutamide formulation.

• Claim 15: This claim focuses on a solid amorphous dispersion. This is the core component of the final pill. It protects the mixture of enzalutamide and the HPMCAS polymer itself, where the enzalutamide makes up 55% to 65% of the dispersion by weight.

Litigation:

U.S. Patent 11,839,689 has been the subject of patent infringement litigation. In August 2024, Astellas Pharma Inc. and Pfizer's Medivation unit filed a lawsuit against Qilu Pharmaceutical Co. in the U.S. District Court for the District of New Jersey. The suit alleges that Qilu's proposed generic version of the drug Xtandi® (enzalutamide) infringes on this patent, among others. The patent is also listed in connection with Abbreviated New Drug Application (ANDA) court cases, which are common when generic drug manufacturers challenge the patents of brand-name drugs. As of today's date, there are no documented proceedings related to this patent in the 2026 dockets of the Court of Appeals for the Federal Circuit (CAFC), indicating that the district court cases are likely ongoing.

Based on the legal status information provided for US patent 11,839,689 and cross-referencing with public litigation databases, the following lawsuits involving this patent have been identified. These cases are part of the broader litigation surrounding generic versions of the drug Xtandi® (enzalutamide).

As of today's date, May 1, 2026, these cases are understood to be active, with no final, unappealable judgments rendered.

Litigation Summary

Citations for the litigation information are derived from the legal events data provided for US patent 11,839,689 on Google Patents, which aggregates data from sources like Darts-ip and Unified Patents. The case numbers link to these dockets (e.g., https://portal.unifiedpatents.com/litigation/New%20Jersey%20District%20Court/case/2%3A24-cv-09403).

Proceedings overview

There are no AIA trial proceedings on file for US patent 11,839,689 as of the most recent ingest from the USPTO ODP API. Therefore, there is no PTAB activity to report.

Strategic summary

As of today's date, May 30, 2026, all claims of US patent 11,839,689 remain untested by any AIA trial proceeding. This means that if a defendant is facing assertion of this patent, all claims are currently presumed valid from a PTAB perspective.

Since there are no PTAB proceedings, there is no estoppel landscape to consider under 35 U.S.C. § 315(e)(2). All prior-art grounds remain available for a potential petitioner.

The absence of PTAB activity for a patent involved in ongoing litigation, as detailed in the "Litigation summary" section, is notable. Well-asserted patents often become targets for IPRs or other AIA trials.

Recommended next steps

If you are a defendant facing assertion of US patent 11,839,689, it is important to note the lack of PTAB activity. This means the patent's claims have not been challenged before the PTAB. Considering the ongoing district court litigation, an analysis of potential prior art for an IPR or PGR filing could be a viable defensive strategy, as no estoppel would apply from previous PTAB proceedings.

Inventors

• Douglas Alan Lorenz (Bend Research, Inc. at time of priority date based on confirmatory assignments)
• Sanjay Konagurthu (Bend Research, Inc. at time of priority date based on confirmatory assignments)
• Randy J. Wald (Bend Research, Inc. at time of priority date based on confirmatory assignments)
• Jason A. Everett (Bend Research, Inc. at time of priority date based on confirmatory assignments)
• Sheila Matz (Medivation Prostate Therapeutics, Inc. at time of priority date based on confirmatory assignment)
• Yuuki Takaishi (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)
• Toshiro Sakai (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)
• Ryousuke Irie (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)
• Shinsuke Oba (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)
• Hiroyasu Toyota (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)
• Koji Nishimura (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)
• Atsushi Kanbayashi (Astellas Pharma Inc. at time of priority date based on confirmatory assignment)

It is notable that some inventors appear to be associated with Bend Research, Inc. while others are associated with Astellas Pharma Inc. and Medivation Prostate Therapeutics, Inc. at the time of the priority date, suggesting a collaborative development effort or subsequent assignment of inventorship rights.

Original assignee

Astellas Pharma Inc. and Medivation Prostate Therapeutics LLC are listed as the original assignees on the issued patent.

Astellas Pharma Inc. is a Japanese multinational pharmaceutical company, and Medivation Prostate Therapeutics LLC is a subsidiary of Pfizer, which acquired Medivation, Inc. in 2016. Both are operating companies that develop and ship pharmaceutical products. Xtandi® (enzalutamide) is a product embodying the claims of this patent, and it is marketed by Astellas and Pfizer (through Medivation). Both companies are currently operating.

Assignment timeline

The USPTO Assignment Center (https://assignmentcenter.uspto.gov/) was searched for patent number 11839689. The following assignment records were found:

• 2023-04-19 (executed) / recorded 2023-04-19 — Reel 063077/0681

  • Conveyance: Reassignment
  • Assignor: LLC, MEDIVATION PROSTATE THERAPEUTICS, LLC
  • Assignee: LLC, MEDIVATION PROSTATE THERAPEUTICS, LLC
  • Correspondent: MCDERMOTT WILL & EMERY LLP, 500 NORTH CAPITAL STREET, N.W., WASHINGTON, DC 20001
  • Context: Change of Address (as stated in the record)

• 2023-06-28 (executed) / recorded 2023-06-28 — Reel 063428/0173

  • Conveyance: Reassignment
  • Assignor: MEDIVATION PROSTATE THERAPEUTICS LLC
  • Assignee: MEDIVATION PROSTATE THERAPEUTICS LLC
  • Correspondent: MCDERMOTT WILL & EMERY LLP, 500 NORTH CAPITAL STREET, N.W., WASHINGTON, DC 20001 (This correspondent also appears in Reel 063077/0681 for this patent.)
  • Context: Correction of Date and Names in Coversheet (as stated in the record)

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0136

  • Conveyance: Confirmatory Assignment
  • Assignor: LORENZ, DOUGLAS ALAN; WALD, RANDY J; EVERETT, Jason A; KONAGURTHU, SANJAY
  • Assignee: BEND RESEARCH, INC.
  • Correspondent: KOLLEGE, DARYL, LONZA, 900 CHEYNEY ROAD, GLEN MILLS, PA 19342
  • Context: Confirmatory assignment from individual inventors to Bend Research, Inc. Bend Research, Inc. specializes in formulation development, including spray-dried dispersions, which are relevant to this patent.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0137

  • Conveyance: Assignment of Assignors Interest
  • Assignor: KONAGURTHU, SANJAY; WALD, RANDY J; LORENZ, DOUGLAS ALAN; EVERETT, Jason A
  • Assignee: BEND RESEARCH
  • Correspondent: KOLLEGE, DARYL, LONZA, 900 CHEYNEY ROAD, GLEN MILLS, PA 19342 (This correspondent also appears in Reel 064284/0136 for this patent.)
  • Context: Assignment from individual inventors to Bend Research.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0138

  • Conveyance: Assignment of Assignors Interest
  • Assignor: MATZ, SHEILA
  • Assignee: MEDIVATION PROSTATE THERAPEUTICS, INC.
  • Correspondent: MCDERMOTT WILL & EMERY LLP, 500 NORTH CAPITAL STREET, N.W., WASHINGTON, DC 20001 (This correspondent also appears in Reel 063077/0681 and 063428/0173 for this patent.)
  • Context: Assignment from individual inventor to Medivation Prostate Therapeutics, Inc.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0139

  • Conveyance: Confirmatory Assignment
  • Assignor: BEND RESEARCH, INC.
  • Assignee: MEDIVATION LLC
  • Correspondent: KOLLEGE, DARYL, LONZA, 900 CHEYNEY ROAD, GLEN MILLS, PA 19342 (This correspondent also appears in Reel 064284/0136 and 064284/0137 for this patent.)
  • Context: Confirmatory assignment from Bend Research, Inc. to Medivation LLC. Bend Research was acquired by Capsugel in 2013, which was then acquired by Lonza in 2017.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0140

  • Conveyance: Assignment of Assignors Interest
  • Assignor: MEDIVATION LLC
  • Assignee: MEDIVATION PROSTATE THERAPEUTICS LLC
  • Correspondent: MCDERMOTT WILL & EMERY LLP, 500 NORTH CAPITAL STREET, N.W., WASHINGTON, DC 20001 (This correspondent also appears in Reel 063077/0681, 063428/0173, and 064284/0138 for this patent.)
  • Context: Assignment from Medivation LLC to Medivation Prostate Therapeutics LLC. Medivation was acquired by Pfizer in 2016.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0141

  • Conveyance: Assignment of Assignors Interest
  • Assignor: TOYOTA, Hiroyasu; IRIE, Ryousuke; OBA, SHINSUKE; KANBAYASHI, ATSUSHI; TAKAISHI, YUUKI; NISHIMURA, KOJI; SAKAI, TOSHIRO
  • Assignee: ASTELLAS PHARMA INC.
  • Correspondent: OLSON & PONS, 6303 OWEN MOUTH ROAD, WOODLAND HILLS, CA 91367
  • Context: Assignment from individual inventors to Astellas Pharma Inc.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0142

  • Conveyance: Change of Address
  • Assignor: MEDIVATION PROSTATE THERAPEUTICS LLC
  • Assignee: MEDIVATION PROSTATE THERAPEUTICS LLC
  • Correspondent: MCDERMOTT WILL & EMERY LLP, 500 NORTH CAPITAL STREET, N.W., WASHINGTON, DC 20001 (This correspondent also appears in Reels 063077/0681, 063428/0173, 064284/0138, and 064284/0140 for this patent.)
  • Context: Change of Address (as stated in the record)

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0143

  • Conveyance: Change of Name
  • Assignor: MEDIVATION PROSTATE THERAPEUTICS, INC.
  • Assignee: MEDIVATION PROSTATE THERAPEUTICS LLC
  • Correspondent: MCDERMOTT WILL & EMERY LLP, 500 NORTH CAPITAL STREET, N.W., WASHINGTON, DC 20001 (This correspondent also appears in Reels 063077/0681, 063428/0173, 064284/0138, 064284/0140, and 064284/0142 for this patent.)
  • Context: Change of Name (as stated in the record)

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0144

  • Conveyance: Confirmatory Assignment
  • Assignor: LORENZ, DOUGLAS ALAN; WALD, RANDY J; EVERETT, Jason A; KONAGURTHU, SANJAY
  • Assignee: BEND RESEARCH INC.
  • Correspondent: KOLLEGE, DARYL, LONZA, 900 CHEYNEY ROAD, GLEN MILLS, PA 19342 (This correspondent also appears in Reels 064284/0136, 064284/0137, and 064284/0139 for this patent.)
  • Context: Confirmatory assignment from individual inventors to Bend Research Inc.

• 2023-10-30 (executed) / recorded 2023-10-30 — Reel 064284/0145

  • Conveyance: Change of Address
  • Assignor: ASTELLAS PHARMA INC.
  • Assignee: ASTELLAS PHARMA INC.
  • Correspondent: OLSON & PONS, 6303 OWEN MOUTH ROAD, WOODLAND HILLS, CA 91367 (This correspondent also appears in Reel 064284/0141 for this patent.)
  • Context: Change of Address (as stated in the record)

Timeline diagram

timeline
    title Ownership of US 11839689
    2022 : Application filed by Astellas/Medivation
    2023 : Medivation LLC change address
         : Medivation LLC correct name
         : Inventors to Bend Research
         : Matz to Medivation Prostate Inc
         : Bend Research to Medivation LLC
         : Medivation LLC to Medivation Prostate LLC
         : Astellas inventors to Astellas
         : Medivation Prostate LLC change address
         : Medivation Prostate Inc change name
         : Inventors to Bend Research Inc
         : Astellas change address
    2023 : Patent Issued

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The transfers involve Medivation Prostate Therapeutics LLC, Medivation LLC, and Bend Research, Inc., which are all entities associated with operating pharmaceutical companies (Pfizer/Astellas and Lonza, respectively). The assignments primarily concern clarifying ownership paths from inventors and between corporate entities following acquisitions.
2. Known asserter in the chain — not present. The assignees, Astellas Pharma Inc. and Medivation Prostate Therapeutics LLC (a Pfizer subsidiary), are operating pharmaceutical companies.
3. Repeat correspondent across the chain — present. McDermott Will & Emery LLP appears as correspondent for multiple "Medivation" entities across several assignments (Reels 063077/0681, 063428/0173, 064284/0138, 064284/0140, 064284/0142, 064284/0143). Daryl Kollege of Lonza appears as correspondent for multiple "Bend Research" assignments (Reels 064284/0136, 064284/0137, 064284/0139, 064284/0144). Olson & Pons appear for Astellas Pharma Inc. in two records (Reels 064284/0141, 064284/0145). This is consistent with in-house or regular external counsel managing intellectual property for large corporations.
4. Cascading transfers — present. There are numerous assignments and reassignments recorded on the same date (2023-10-30), clarifying the ownership path from multiple inventors and through corporate acquisitions. This includes transfers from inventors to Bend Research, from Bend Research to Medivation LLC, and from Medivation LLC to Medivation Prostate Therapeutics LLC, as well as separate inventor assignments to Astellas. This appears to be a cleanup of the record prior to patent issuance.
5. Pre-litigation transfer — not present. The assignments were recorded in 2023, while the identified litigation began in 2024. The patent was also granted in December 2023. These assignments occurred prior to or around the time of patent issuance and before litigation commenced.
6. Bankruptcy fire-sale — not present. There is no indication that Astellas, Medivation, or Bend Research (or its parent companies Capsugel/Lonza) have filed for bankruptcy and sold their patent assets.
7. Privateering — not present. The current assignees are the operating companies that directly manufacture and sell the product embodying the patent claims.
8. Defensive aggregator (anti-NPE) — not present. The current assignees are operating companies, not defensive aggregators.

Verdict

Operating-company assertion

The detailed assignment records reflect a series of internal corporate actions, including confirmatory assignments from inventors and transfers between corporate entities following acquisitions (Medivation by Pfizer, Bend Research by Capsugel/Lonza). The current assignees, Astellas Pharma Inc. and Medivation Prostate Therapeutics LLC (a Pfizer subsidiary), are operating pharmaceutical companies that manufacture and sell products embodying the patent, and they are asserting the patent against alleged generic infringers.

USPTO Assignment Center search: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US patent 11,839,689 under 35 U.S.C. § 102, we examine the references cited within the patent and consider the patent's priority date of September 11, 2012. We also incorporate relevant information from the previous "Obviousness Analysis" section, which identified US 2014/0100256 A1 as a key prior art reference based on its earlier provisional filing date.

The following prior art documents are analyzed for their potential to anticipate claims 1, 8, and 15 of US 11,839,689.

Most Relevant Prior Art for US Patent 11,839,689

1. U.S. Patent 7,709,517 B2 (Chen et al.)

   • Full Citation: U.S. Patent No. 7,709,517 B2
   • Publication Date: May 4, 2010
   • Brief Description: This patent discloses the chemical compound enzalutamide (also referred to as MDV3100 or RD162) and methods for its use in treating various hyperproliferative disorders, including prostate cancer, breast cancer, and ovarian cancer. It provides the chemical structure of enzalutamide.
   • Potential Anticipation of Claims:
     • Claim 8 (Method of treating prostate cancer): This patent anticipates the general concept of treating prostate cancer with enzalutamide. However, Claim 8 of US 11,839,689 specifies administering "the pharmaceutical composition of claim 1," which includes specific formulation details (amorphous enzalutamide, HPMCAS, and a specific disintegrant concentration). Since US 7,709,517 B2 does not disclose these specific formulation details, it does not anticipate Claim 8 in its entirety under 35 U.S.C. § 102. It serves as prior art for the drug and its therapeutic use, making the use of an improved formulation for this purpose potentially obvious under § 103, but not strictly anticipatory of the specific formulation.

2. WO 2006/124118 A1

   • Full Citation: WO 2006/124118 A1
   • Publication Date: November 23, 2006
   • Brief Description: This international patent application is associated with the initial discovery and therapeutic applications of enzalutamide (MDV3100) as an androgen receptor signaling inhibitor, particularly for treating prostate cancer. It describes the compound and its broad pharmaceutical uses.
   • Potential Anticipation of Claims:
     • Similar to US 7,709,517 B2, this publication discloses the active pharmaceutical ingredient (enzalutamide) and its use in treating prostate cancer. However, it does not disclose the specific amorphous solid dispersion formulation with HPMCAS and the specified disintegrant concentration as required by Claim 1. Therefore, it does not anticipate Claims 1, 8, or 15 of US 11,839,689 under 35 U.S.C. § 102.

3. U.S. Patent Application Publication No. US 2014/0100256 A1 (Lorenz et al.)

   • Full Citation: U.S. Patent Application Publication No. US 2014/0100256 A1
   • Publication/Filing Date: Published April 10, 2014; claims priority to U.S. Provisional Application No. 61/533,702, filed September 12, 2011. The effective prior art date for disclosures supported by this provisional application is September 12, 2011, which precedes the priority date of US 11,839,689 (September 11, 2012).
   • Brief Description: This publication, titled "Formulations of Enzalutamide," describes solid formulations of enzalutamide, specifically focusing on solid amorphous dispersions with concentration-enhancing polymers to improve solubility and absorption. It explicitly names HPMCAS as a suitable polymer. The disclosure details ranges for drug loading (e.g., greater than 50 wt% and less than 70 wt% enzalutamide in the dispersion), the amorphous state of enzalutamide (at least 60% amorphous), and various excipients including disintegrants at specific concentrations in tablet formulations (e.g., 6-10 wt% disintegrant). It also references the use of enzalutamide for treating prostate cancer.
   • Potential Anticipation of Claims:
     • Claim 1 (Solid pharmaceutical composition): US 2014/0100256 A1 explicitly discloses a solid pharmaceutical composition comprising amorphous enzalutamide dispersed in HPMCAS, where at least 60% of the enzalutamide is amorphous (e.g., paragraph). It also describes tablet formulations containing 60% enzalutamide (by weight) in an HPMCAS dispersion (e.g., "60% A:HPMCAS-M dispersion" in paragraph), which when formulated for a 160 mg dose of enzalutamide (160 mg / 0.60 = 266.67 mg dispersion) matches the claimed enzalutamide amount. Furthermore, it explicitly states that such tablets comprise "6 to 10 wt % disintegrant," providing examples with 8 wt% croscarmellose sodium (e.g., paragraphs-). Therefore, US 2014/0100256 A1 appears to explicitly disclose every element of Claim 1, arranged as in the claim, and thus potentially anticipates it.
     • Claim 8 (Method of treating prostate cancer): This publication teaches administering the disclosed compositions (which, as discussed above, include those anticipating Claim 1) for treating hyperproliferative disorders such as prostate cancer (e.g., paragraph). Given that the composition of Claim 1 is potentially anticipated, and the method of using it for its known purpose (treating prostate cancer) is also disclosed, Claim 8 is potentially anticipated.
     • Claim 15 (Solid amorphous dispersion): US 2014/0100256 A1 discloses "a solid amorphous dispersion comprising enzalutamide and HPMCAS" (e.g., abstract, paragraph). It further specifies that "dispersions comprise greater than 50 wt % and less than 70 wt % enzalutamide" (e.g., paragraph), which directly encompasses the claimed range of "55% to 65% by weight." An example of a "60% A:HPMCAS-M dispersion" is also explicitly provided (e.g., paragraph), which falls within this range. Therefore, Claim 15 is potentially anticipated by this publication.

Obviousness Analysis of US Patent 11,839,689 under 35 U.S.C. § 103

This analysis evaluates the obviousness of US Patent 11,839,689, which claims formulations of enzalutamide, under 35 U.S.C. § 103. The claims generally focus on solid amorphous dispersions of enzalutamide with hydroxypropylmethylcellulose acetate succinate (HPMCAS) and a specific disintegrant concentration for treating prostate cancer.

Person Having Ordinary Skill in the Art (PHOSITA)

A PHOSITA in this field would be a pharmaceutical scientist or formulator with experience in developing oral dosage forms for poorly water-soluble drugs, particularly anticancer agents. They would possess knowledge of different formulation techniques, excipients, and methods to improve drug solubility, dissolution, and bioavailability.

Claim 1: Solid Pharmaceutical Composition

Claim 1 describes a solid pharmaceutical composition comprising about 160 mg of enzalutamide, wherein at least 60% of the enzalutamide is amorphous, dispersed in HPMCAS, and further comprising 6-10% by weight of a disintegrant.

Combination of References: US 2014/0100256 A1 (Lorenz et al.) in view of general knowledge regarding solid dispersions, enzalutamide dosage, and common pharmaceutical excipients.

Rationale for Obviousness:

1. Amorphous Enzalutamide and HPMCAS in Solid Dispersions: US 2014/0100256 A1, which shares inventors and a priority date with US 11,839,689, explicitly discloses solid formulations comprising amorphous enzalutamide and pharmaceutical compositions comprising a solid dispersion containing enzalutamide and at least one polymer. It specifically identifies HPMCAS as a concentration-enhancing polymer suitable for use in enzalutamide dispersions. The patent also states that enzalutamide dispersions with HPMCAS can be made by spray-drying. The disclosure notes that "at least a major portion" (at least 60%) of the enzalutamide in the composition should be amorphous to improve solubility and absorption. The use of amorphous solid dispersions (ASDs) to enhance the solubility and bioavailability of poorly water-soluble drugs like enzalutamide was a well-known technique in the pharmaceutical industry prior to the priority date of US 11,839,689. HPMCAS was a recognized and effective polymer for ASD formulations due to its ability to solubilize poorly soluble drugs, promote rapid dissolution, and prevent precipitation.

2. Enzalutamide Dosage (160 mg): Enzalutamide was approved for treating castration-resistant prostate cancer, and a recommended dose of 160 mg orally once daily was known in the prior art, often administered as four 40 mg capsules. A PHOSITA would recognize the advantage of formulating this 160 mg dose into a single, compact tablet for patient convenience, especially given the existing "pill burden" from multiple soft gel capsules.

3. Disintegrants (6-10% by weight): US 2014/0100256 A1 also broadly discloses that the solid dispersion of enzalutamide and polymer can be mixed with one or more pharmaceutically acceptable additives, including disintegrants. Examples of disintegrants listed in the patent include croscarmellose sodium and sodium starch glycolate, which are commonly used in pharmaceutical formulations. The general knowledge in pharmaceutical formulation would include the use of disintegrants to aid in tablet disintegration and drug release, with typical ranges for disintegrant concentrations being well-established. For example, a tablet formulation in the patent itself explicitly states that tablets comprising 60% A:HPMCAS-M dispersion can comprise 6 to 10 wt % disintegrant, and provides examples of tablets with 8 wt% croscarmellose sodium. This indicates that the specific range of 6-10% by weight would be a routine optimization for a PHOSITA to achieve desired dissolution profiles.

Therefore, combining these elements would have been obvious to a PHOSITA who would understand the need to improve enzalutamide's bioavailability, formulate a convenient 160 mg dosage, and apply routine pharmaceutical formulation techniques, including using a well-known concentration-enhancing polymer like HPMCAS and a conventional amount of disintegrant.

Claim 8: Method of Treating Prostate Cancer

Claim 8 describes a method of treating prostate cancer by administering the pharmaceutical composition of Claim 1.

Combination of References: US 2014/0100256 A1 (Lorenz et al.) in view of the known therapeutic use of enzalutamide.

Rationale for Obviousness:

1. Enzalutamide for Prostate Cancer: The use of enzalutamide to treat prostate cancer, including castration-resistant prostate cancer, was well-established in the prior art. U.S. Pat. No. 7,709,517 (cited in US 11,839,689 and US 2014/0100256 A1) already disclosed enzalutamide and its method of use for treating prostate cancer.

2. Administration of Improved Formulations: Given that US 2014/0100256 A1 already teaches amorphous enzalutamide with HPMCAS to improve solubility and absorption (as discussed for Claim 1), it would have been obvious to a PHOSITA to administer this improved formulation for the known treatment of prostate cancer. The goal of such formulations is precisely to enhance the therapeutic effect by increasing bioavailability.

Therefore, using an improved formulation of a known drug for its known therapeutic indication would be a straightforward and obvious application for a PHOSITA.

Claim 15: Solid Amorphous Dispersion

Claim 15 describes a solid amorphous dispersion comprising enzalutamide and HPMCAS, where the enzalutamide constitutes 55% to 65% by weight of the dispersion.

Combination of References: US 2014/0100256 A1 (Lorenz et al.) in view of general knowledge regarding optimizing solid dispersion drug loading.

Rationale for Obviousness:

1. Solid Amorphous Dispersion of Enzalutamide and HPMCAS: As established with Claim 1, US 2014/0100256 A1 explicitly teaches solid amorphous dispersions of enzalutamide and HPMCAS to enhance solubility and absorption.

2. Drug Loading (55-65% by weight): US 2014/0100256 A1 broadly discloses compositions containing from about 1 to about 80 wt% enzalutamide in the dispersion, and more specifically states that "dispersions comprise greater than 50 wt % and less than 70 wt % enzalutamide." The range of 55-65% by weight falls directly within this disclosed range of 50-70 wt%. A PHOSITA would recognize that optimizing the drug loading in an amorphous solid dispersion is a routine experimental parameter, balancing desired drug concentration, physical stability, and processing feasibility. Various prior art references discuss the impact of drug loading on the performance of ASDs and the need for optimization. Given the explicit disclosure of ranges encompassing 55-65% enzalutamide, selecting this specific sub-range would be a matter of routine optimization, not inventive ingenuity. The patent itself mentions that optimum results are best determined by in vitro dissolution and/or in vivo bioavailability tests.

Therefore, the solid amorphous dispersion of enzalutamide and HPMCAS with a drug loading of 55-65% by weight would have been obvious to a PHOSITA in light of US 2014/0100256 A1 and routine optimization practices for solid dispersions.

I'll research this systematically, starting with searches for the patent's term adjustment, family, and continuations.

Key data found. Now let me dig into the specific term-adjustment record and the continuation family.

US 11,839,689 — Term, Extension, and Family Analysis

Scope note: Per the header of this task, working date is 2026-09-22 (note: the body text of the prompt says "Current Date: April 26, 2026" — this internal inconsistency is flagged below). All figures below are from the sources retrieved today; where a source renders a date differently by one calendar day, I say so rather than harmonizing it.

1. Identity confirmation (verified, not auto-corrected)

The 2013-09-11 anchor is corroborated independently: the 30-month national-stage entries in the family fall on 2015-03-11, which is exactly 30 months after 2013-09-11.

2. Patent Term Adjustment (PTA) — 35 U.S.C. § 154(b)

Bottom line: the reported expiration date is identical to the unadjusted 20-year date, which implies a PTA of zero (0) days.

Reasoning:

1. Term base. US 11,839,689 is a continuation. Under 35 U.S.C. § 154(a)(2) its 20-year term runs from the earliest U.S. non-provisional filing in the § 120 chain — here the 2013-09-11 international/non-provisional filing → 2033-09-11.
2. A-delay (§ 154(b)(1)(A)). Measured from the actual filing date of this application (2022-11-11) to issuance (2023-12-12) — roughly 396 days, i.e., well under three years. A-delay = 0.
3. B-delay (§ 154(b)(1)(B)). Any B-delay would be limited to discrete USPTO missed deadlines (e.g., issuance more than 4 months after notice of allowance). With a ~13-month pendency and a normal issue-fee/issuance sequence, any B-delay would be small or nil.
4. Continuing-application limitation. 37 C.F.R. § 1.704(c)(11) expressly provides that for a patent issuing from a continuing application, the PTA "shall not include any period that is prior to the actual filing date of the application that resulted in the patent." The ~9-year pendency of the parent family therefore generates no PTA for the '689 patent.
5. Reconciliation with the published data. Google Patents lists "Adjusted expiration 2033-09-11" — precisely the unadjusted 20-year date. A positive PTA would push this later. GreyB/Pharsight and Drugs.com both list Sep 11, 2033. Unified Patents lists 2033-09-10 and application date 2022-11-10 (a one-day rendering offset, same calendar day).

Verification caveat: I could not retrieve the literal front-page statement ("The term of this patent is extended or adjusted under 35 U.S.C. 154(b) by N days") or the USPTO Patent Term Adjustment determination printout from Patent Center in this session. If a definitive number is required for litigation or diligence, pull the patent's cover page or the PTA determination in USPTO PatentCenter/Patent Public Search. The derivation above, however, is self-consistent with three independent expiration listings.

3. Patent Term Extension (PTE) — 35 U.S.C. § 156 (Hatch-Waxman)

No PTE has been granted for US 11,839,689, and on the record available it is not available to it.

• The listed expiry for the '689 patent (2033-09-11) equals its unadjusted 20-year date; no regulatory extension is reflected in any of the Orange Book / DrugPatentWatch / Google Patents expiration entries.

• Statutory bar: § 156(d)(1) requires the PTE application to be filed within 60 days beginning on the date the product received marketing permission. The relevant regulatory reviews long predate issuance of this patent:

  • XTANDI capsules, NDA 203415 — approved 2012-08-31
  • XTANDI tablets, NDA 213674 — approved 2020-08-04

  US 11,839,689 did not issue until 2023-12-12, i.e., more than three years after the most recent relevant approval, and roughly eleven years after the capsule approval. There is no timely PTE window available for this patent.

• Only one patent per regulatory review period may be extended (§ 156(c)(4)), and the '689 patent's term is already the latest-dated term in the Xtandi estate.

• Even hypothetically, the § 156 cap would limit extension (max 5 years; and total term not to exceed 14 years from approval — 2020-08-04 + 14 = 2034-08-04) — but the procedural bar above is dispositive.

Foreign counterparts: The European family members (EP 2895463; EP 3725778) carry expiration date 10/09/2033 (NL register) / 11/09/2033 (LU register) — again the same calendar date rendered two ways. DrugPatentWatch displays a "Supplementary Protection Certificate / SPC expiration" column for the international family, but I could not verify any SPC values in this session. Treat SPC status in EPO states as unverified.

4. Continuation applications (US)

The '689 patent is one node in a long-running continuation chain. Applications identified from Google Patents "Priority Applications / Family Applications After" data and corroborating sources:

Additional applications likely in the same family but whose exact lineage I could not verify: US 12,447,128 B2 ("Formulations of enzalutamide," claims directed to two-tablet regimens of 80 mg amorphous enzalutamide + 400 mg HPMCAS) and pending publication US 2025/0090465 A1. Flagging these as observed, unverified parentage — do not rely on them without a PatentCenter family lookup.

Because all of these are § 120 continuations (not independent filings), each shares the same 20-year term base of 2013-09-11, subject to its own PTA computation.

5. Divisional applications

US: No U.S. divisional application (i.e., one filed in response to a restriction requirement under 35 U.S.C. § 121) was identified in the sources retrieved. The U.S. members of this family are continuations. I did not have access to the PatentCenter continuity data tab in this session, so this is a negative finding on available evidence, not a certification.

Foreign: Divisional activity is confirmed in the European family:

The NL register for EP 3725778 expressly records: "Application number/publication number of the divisional application (Art. 76) changed."

Japanese family also shows a divisional: JP 2021178871 A (published 2021-11-25) appears in the same family group.

EP opposition: EP 2895463 was granted 2021-08-18 and an opposition procedure started 2022-06-29; the B2 publication on 2026-01-07 indicates the patent was maintained in amended form. This is a live, material validity proceeding abroad that the earlier "PTAB challenges" section (which addressed only U.S. AIA trials) does not capture.

6. Related family members

DrugPatentWatch states the '689 patent "has forty-nine patent family members in twenty-nine countries." Verified members from the retrieved registers:

7. Projected expiration date

Practical conclusion: US 11,839,689 expires 11 September 2033 — subject only to maintenance-fee payment — and the entire U.S. continuation family terminates on that same date, because the URAA 20-year-from-earliest-filing rule prevents any continuation from outliving its parent chain. This is the single most important commercial fact for generic entry timing: no member of this family can be extended past 2033-09-11 by continued filing activity.

Maintenance fees. Grant date 2023-12-12 → the 3.5-year fee window opens ~2027-06-12 and the 7.5-year window ~2031-06-12; both fall within the term. The 11.5-year window (~2035-06-12) falls after the 2033-09-11 expiry and would not be due if the patent is not otherwise extended. Unified Patents lists a "Lifetime Renewal Fees" figure of $12,600 for this patent and $287,050 across the family; I did not independently audit that against the current USPTO fee schedule.

8. Contradictions / updates to the previously generated sections

Flagging these explicitly, as instructed:

1. Prior art section — priority-date error. The section states US 2014/0100256 A1 "shares inventors and a priority date with US 11,839,689." That is internally inconsistent with the same section, which correctly identifies US 2014/0100256 A1 as claiming priority to provisional 61/533,702, filed 2011-09-12, whereas US 11,839,689's priority provisional is 61/699,351, filed 2012-09-11. US 2014/0100256 A1 is therefore earlier prior art, not co-prioritized. This does not change its status as the strongest § 102/§ 103 reference — it arguably strengthens the anticipation argument — but the "shares a priority date" statement should be corrected.
2. Priority date, one-day discrepancy. Google Patents (2012-09-11), DrugPatentWatch, and the EP registers (11/09/2012 = 11 Sept 2012) all support 2012-09-11. Unified Patents' 2012-09-10 appears to be a timezone rendering artifact. The earlier sections use 2012-09-11, which I concur with.
3. Litigation summary — Hikma case status is stale. The litigation table lists 3:25-cv-00578 as "Active/Ongoing." PACER-derived reporting (PatSnap, citing the 2025-04-07 docket) shows Astellas/Medivation v. Hikma Pharmaceuticals USA — asserting US 11,839,689 B2 and US 12,161,628 B2 — was dismissed with prejudice in 81 days, with each side bearing its own costs and the court retaining jurisdiction to enforce a confidential settlement agreement. That is a Hatch-Waxman negotiated-entry outcome, not an adjudication on validity.
4. Litigation summary — jurisdiction error. The table lists a case in the "Western District of Pennsylvania (2:24-cv-03747)." The underlying Google Patents legal-events feed cites the Eastern District of Pennsylvania for 2:24-cv-03747. There is no W.D. Pa. entry in the source data.
5. PTAB section scope. The "PTAB challenges" analysis is correct as to U.S. AIA trials, but should be read alongside the live EPO opposition on EP 2895463, which resulted in maintenance in amended form (B2, 2026-01-07). Foreign validity has been tested even though U.S. claims have not.
6. Date inconsistency in this prompt. The header says 2026-09-22; the task body says April 26, 2026. The earlier PTAB section is dated May 30, 2026. I have used 2026-09-22 for "current" status.
7. Claim-scope tension. The earlier "Patent summary" describes Claim 1 as requiring "around 160 mg enzalutamide… and a disintegrant at 6–10%." The claim text retrieved from DrugPatentWatch for this patent number shows Claim 1 = "a solid dispersion consisting essentially of amorphous enzalutamide and hydroxypropyl methylcellulose acetate succinate"; the 6–10% croscarmellose sodium limitation appears in claim 7, and the 80 mg tablet strength in claim 5. The claim set appears to have been amended post-issuance via reexamination/reissue or certificate of correction, or the earlier summary conflated claim sets from sibling family members. This should be reconciled against the official US 11,839,689 claim set in PatentCenter before relying on claim scope.

9. Confidence summary

Recommended verification steps: (a) pull the front page of US 11,839,689 and the USPTO Patent Term Adjustment determination to fix the PTA figure at a number rather than an inference; (b) pull the PatentCenter "Continuity Data" tab for US 17/985,235 to enumerate the exact § 120 chain and confirm no divisional; (c) pull the official claim set to resolve the claim-scope discrepancy in item 8.7; (d) confirm current maintenance-fee payment status.