US 10585097

I'll search for the specific patent number and check current docket/legal status sources.

Let me verify the claims and check for any CAFC/litigation status.

Let me check the specific claims text and any litigation/PTAB records for this exact patent.

US 10,585,097 B2 — Summary

Important caveat on identifiers: I interpreted the number literally as US 10,585,097 (eleven digits pattern 10585097). Searches keyed on similar numbers surfaced different patents (e.g., US 11,050,097 B2, which is a Duesenfeld GmbH battery‑recycling patent in IPR2024‑00887 / a Jan. 2026 CAFC appeal). Those are not the patent you asked about and I excluded them. I did not find any CAFC 2026 docket or district‑court/PTAB proceeding naming US 10,585,097; searches are non‑exhaustive, so treat that as "none found" rather than "none exists."

Bibliographic data (from the authoritative patent text you supplied)

Abstract (verbatim)

"Herein is reported a method for determining bacterial endotoxin at low concentrations in a sample of an antibody (that has been produced using bacterial cells) comprising the following steps in the following order: i) adding magnesium ions to the sample, ii) diluting the sample, iii) dialyzing the sample having a pH‑value of 5.7‑8.0 against an endotoxin‑free aqueous solution, and iv) determining bacterial endotoxin in the sample using a bacterial endotoxin test, particularly the limulus amoebocyte lysate assay."

Technical problem and gist

The patent addresses the Low Endotoxin Recovery (LER) effect — the phenomenon by which endotoxin spiked into certain antibody formulations (notably those with a polysorbate detergent plus citrate or phosphate buffer) becomes "masked," so a standard Limulus amoebocyte lysate (LAL)/bacterial endotoxin test (BET) under‑reports endotoxin, creating a safety risk for injectables. The claimed approach is a specific, ordered sample‑preparation sequence that "unmasks" endotoxin and restores 50–200% recovery of spiked control standard endotoxin (CSE). The specification stresses that both the combination and the sequence of steps matter; a reference example in which the order was reversed (dilution → dialysis → Mg²⁺ addition) failed to give satisfactory recovery.

Preferred/working parameters disclosed: Mg²⁺ as MgCl₂ to ~10–100 mM (optimally ~50 mM, i.e., ~twice the citrate buffer concentration); dilution ~1:5 to 1:20 (preferably 1:10) with endotoxin‑free water; dialysis against endotoxin‑free water at pH 5.7–8.0 (preferably 6.5–7.5), e.g., ~24 h with a ~10 kDa cellulose acetate membrane; then LAL assay, preferably kinetic chromogenic. The working example antibody is rituximab (SEQ ID NOs: 1 and 2), formulated with ~25 mM sodium citrate and ~700 mg/L polysorbate 80 at pH ~6.5.

Independent claims — plain‑language overview (with uncertainty flag)

⚠️ Note: The authoritative text you provided was truncated before the claims section, so I cannot quote the literal claim language or confirm exact claim numbering/dependencies. The following is inferred from the specification's own "the present invention relates to…" statements and should be verified against the granted claims on USPTO PatentCenter.

• Independent claim — sample‑preparation method (steps (a)–(c)): A method for preparing an antibody‑containing sample for a bacterial endotoxin test (preferably an LAL assay), comprising, in this order: (a) adding magnesium ions (preferably MgCl₂) to the sample; (b) diluting the sample; and (c) dialyzing the sample, where the sample has a pH of 5.7–8.0 (specification also states 5.7–9.0 in places), against an endotoxin‑free aqueous solution. Effect: the sample becomes reactive to factor C in the LAL enzymatic cascade / the LER effect is overcome.

• Independent claim — endotoxin‑determination method (steps (a)–(d)): A method for determining bacterial endotoxin in an antibody‑containing sample (one that preferably exhibits the LER effect), comprising, in this order: (a) adding magnesium ions; (b) diluting; (c) dialyzing at pH 5.7–8.0 against an endotoxin‑free aqueous solution; and (d) determining bacterial endotoxin using a bacterial endotoxin test / LAL assay (kinetic chromogenic or kinetic turbidimetric being prioritized).

• Possible further independent claims (use/kit‑type): The specification also frames the invention as (i) a use of the above methods for overcoming the LER effect and (ii) a use for rendering an LER‑exhibiting antibody sample reactive to factor C. Whether these are drafted as separate independent claims in the granted patent is unconfirmed from the text available to me.

Likely dependent‑claim subject matter (again, inferred): antibody is a therapeutic/monoclonal antibody, preferably the anti‑CD20 antibody rituximab; antibody formulated with polysorbate 80 and/or sodium citrate buffer; exclusion of polysorbate 20 and phosphate buffer; 10–100 mM Mg²⁺ (most preferably ~50 mM); dilution 1:5–1:20 (preferably 1:10); dialysis pH 6.5–7.5, ~4–24 h, MWCO ~10 kDa cellulose acetate membrane; dialysis solution optionally containing 2.5–10 mM MgCl₂; inclusion of a "LER positive control" and a positive product control (PPC) with 50–200% recovery.

Uncertainty / openness

• No authoritative confirmation found of: a CAFC 2026 appeal, IPR/PGR, or district‑court case specifically involving US 10,585,097. My searches returned proceedings for other patent numbers, which I did not attribute here.
• Exact granted claim wording, count, and dependency structure could not be verified from the truncated source; consult the USPTO PatentCenter/Global Dossier record for US 15/739,503 and the granted claims.
• Note the specification itself is internally inconsistent on the dialysis pH (5.7–8.0 vs. 5.7–9.0); the claim scope controls.

I'll research litigation involving US patent 10585097 across patent litigation databases.

The initial searches returned unrelated results for different patents. Let me search more specifically on litigation databases.

Let me search litigation-specific databases and the Unified Patents portal directly.

Based on my searches, I must be direct about what I found.

No litigation located for US Patent 10585097

I was unable to locate any litigation involving US Patent 10585097 ("Bacterial endotoxin test for the determination of endotoxins"). My searches returned no results for this specific patent number in any litigation context.

What I searched and what I found

• Queries on patent litigation databases (Unified Patents, PACER-adjacent sources, CAFC opinion repositories) using the exact number 10585097 returned no matching cases. Results returned hits for other patent numbers (e.g., the Ameranth " '850 patent," Sonos, Realtime Data, MCOM IP) — these are unrelated patents, not US 10585097, and I am not treating them as relevant per your instruction not to return results for similar numbers.
• No district court, ITC, PTAB, or Federal Circuit proceeding referencing this patent was surfaced.

Important caveats (please read)

1. This is not proof that no litigation exists. My search coverage is incomplete:
   • PACER is a paywalled, docket-by-docket system that I cannot comprehensively query.
   • Unified Patents' litigation caselist and Docket Navigator are largely subscription/JS-driven and were not fully accessible.
   • PTAB (IPR/PGR) challenges are not "litigation" per se, but I also found no PTAB proceeding for this number.
2. This patent is a diagnostic/QC-method patent (assigned to Forschungszentrum Borstel and Roche entities, granted 2020-03-10, expiring ~2036-07-27). Patents of this type — internal endotoxin-testing methods for antibody manufacturing — are often practiced internally and are less commonly asserted in public infringement suits than, say, therapeutic-compound or device patents. That context is consistent with, but does not establish, the absence of litigation.
3. I did not verify this against a complete, authoritative litigation database, so I cannot state with high confidence that no suits exist.

Recommended next steps for a definitive answer

• Docket Navigator (subscription) — search by patent number across all federal district courts, ITC, and PTAB.
• Lex Machina (subscription) — patent litigation module.
• USPTO Patent Center / Global Dossier for this patent — check the "Litigation" tab and assignment/reassignment records for any recorded court judgments.
• CourtListener/RECAP — full-text docket search for "10585097."
• Roche / Forschungszentrum Borstel investor disclosures and SEC filings — Roche would typically disclose any material patent litigation in its annual report.

If you'd like, I can attempt targeted searches on CourtListener, the ITC EDIS system, or PTAB proceedings specifically (as distinct from district court litigation), or search for assignments/licensing activity that might hint at disputes.

I'll start from the canonical structured data (no AIA proceedings indexed) and then use web search to check for anything the ODP hasn't ingested.

Search noise so far. Let me run more targeted queries keyed to the patent owner, the technology, and the patent number.

No IPR hits yet. Let me check the patent's continuations and any family-wide challenges, plus query PTAB-specific sources directly.

PTAB / AIA Trial Analysis — US Patent 10,585,097

Important framing before the substance: the canonical source for this task — the structured "PTAB proceedings on file" block generated from the USPTO Open Data Portal (ODP) API — returns no AIA trial proceedings for US10585097 as of the most recent ingest. I then ran supplemental web searches (Google/Patents, Docket Alarm, PTAB-related dockets, and technology/party-keyed queries) to catch anything filed but not yet indexed. Nothing on-point surfaced. I am reporting that plainly rather than dressing up unrelated hits as activity. One residual caveat: my last three verification queries (aimed at the family continuation US11360085 and at Docket Alarm's PTAB index) hit a tool step-limit and did not return results, so my check on the continuation is the weakest link in this memo — see "Recommended next steps."

Proceedings overview

Total AIA trial proceedings on US10585097: 0. Breakdown by status: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. The defensive posture this creates is the opposite of a hardened-but-narrowed patent: there is no PTAB record at all, which means all claims stand unadjudicated and intact, no petitioner estoppel exists for you to inherit, and no PTAB final written decision gives you a quotable invalidity finding. Any defendant must build a validity challenge from scratch — there is no free "claims 1-5 are canceled" argument available.

Per-proceeding detail

No proceedings to detail. I did not identify any Inter Partes Review, Post-Grant Review, or Covered Business Method review naming US10585097 as the challenged patent. I will not manufacture proceeding numbers, judges, or dispositions for a docket that does not exist.

For completeness on the "why," a few structural notes about the patent that bear on future AIA exposure:

• Patent identity (from the authoritative patent text): US10585097B2, application 15/739,503, a National Stage of PCT/EP2016/067896 filed 2016-07-27, claiming priority from EP15178683.7 filed 2015-07-28; granted 2020-03-10; anticipated expiration 2036-07-27.
• Ownership: Forschungszentrum Borstel (Leibniz Lungenzentrum) and Roche entities (Roche Diagnostics GmbH / Hoffmann-La Roche Inc.); a 2022-06-15 assignment moved the Borstel interest to Hoffmann-La Roche Inc.
• Subject matter: a sample-prep + BET method — (a) add Mg²⁺, (b) dilute, (c) dialyze at pH 5.7–8.0, (d) run a LAL assay — aimed at defeating the low endotoxin recovery (LER) effect in antibody formulations (rituximab with citrate buffer + polysorbate 80 is the worked example).
• Claim architecture (per the issued-claims listing at Justia): at least two independent claims — claim 1 (method for preparing/determining with steps (a)–(d)) and claim 16 ("method for rendering a sample comprising an antibody reactive to factor C in a LAL enzymatic cascade"), with dependent claims running through at least claim 29 (including claim 15's LER-positive-control step and claims 12–14/27–29 reciting membrane MWCO, cellulose acetate, and water changes). This is a narrow, step-ordered, functional assay method with numeric ranges (e.g., 25 mM citrate / 700 mg/L polysorbate 80; 1:10 dilution; 10 kDa MWCO) — the kind of claim set that tends to attract IPRs if and when it is asserted, because the ranges invite obviousness arguments over the inventors' own cited art (e.g., Tsuji 1983 on magnesium to boost LAL sensitivity; Šourek 1978 on cations and endotoxin; US 4,096,091).
• Continuation in the family: a continuation of application 15/739,503 issued as US11360085 ("Bacterial endotoxin test for the determination of endotoxins"), i.e., there is a live sibling patent with overlapping disclosure. Even family-wide, I found no IPR/PGR.

Strategic summary

Claim status: everything is UNTESTED. No claim of US10585097 has been canceled, confirmed, or otherwise adjudicated by the PTAB. There is no narrowing amendment, no certificate of correction from a trial, and no adverse judgment. If you are on the receiving end of an assertion of this patent, you cannot point to a canceled claim; the entire claim set is in play. Contrast this with the typical well-asserted biopharma patent (the Rituxan-family patents, for example, have accumulated dozens of IPRs), where a defendant usually inherits a map of dead and surviving claims. Here you inherit nothing.

Estoppel landscape: empty, but that cuts both ways. Because no petitioner has taken an IPR to final written decision, there is no § 315(e)(2) estoppel binding anyone — no petitioner, no privy, no real party in interest is precluded from raising any § 102/§ 103 ground. That means you are likewise unconstrained: the full universe of prior art is available to you, including the references already cited in the specification and prosecution history (Tsuji 1983, Šourek 1978, US 4,096,091, Sun 2000, and the LER literature by Chen & Williams that the patent itself characterizes as the state of the art). Conversely, there is no earlier petitioner whose win you could ride, and no defensive-aggregator proceeding to piggyback on.

Pattern signals: none present. No petitioner has filed multiple IPRs against this patent; there is no Unified Patents or RPX-style aggregator challenge in the chain; the patent owner (Roche/Borstel) has not had occasion to defend or appeal any PTAB outcome on this patent. The only ownership signal of note is the 2022-06-15 consolidation of the Borstel interest into Hoffmann-La Roche Inc., which suggests the patent is being held as a single-owner corporate asset — consistent with a company that would assert or license it centrally, and would have both the incentive and the resources to contest any IPR vigorously.

Why the silence is itself a signal. This patent (granted 2020-03-10) has been eligible for IPR for roughly five years and has attracted zero petitions. The usual explanation is commercial, not legal: an assay/quality-control method patent sitting inside Roche's own portfolio, covering a testing methodology rather than a therapeutic composition, is unlikely to have been asserted against competitors — and without assertion, there is no § 315(b) trigger and little motivation for a competitor to spend ~$500k per IPR. The absence of PTAB activity here most likely means the patent has not been wielded offensively, not that it is unassailable.

Recommended next steps

• If you have received a demand letter or been served with an infringement complaint asserting US10585097: the PTAB clock analysis starts with your service date. Under § 315(b) you have one year from service of a complaint alleging infringement to file an IPR; after that, the bar attaches. Since no IPR exists, you have a clean slate — build the invalidity case on the specification's own admitted art (the LER literature and the magnesium/LAL references) plus the prosecution history.
• Confirm the continuation before you commit strategy. The sibling patent US11360085 (continuation of application 15/739,503) carries overlapping claims and is a live asset. My verification search on that number did not complete (tool step-limit), so treat the family status as unconfirmed. Run a fresh ODP / PTAB E2E search for US11360085 and for application 15/739,503 before finalizing any freedom-to-operate or invalidity opinion — a challenge to the '097 patent alone may be moot if the '085 continuation is also being asserted.
• No appeal posture to check. There is no FWD on this patent and therefore no Federal Circuit docket, no CourtListener opinion, and no PTAB E2E trial record to link. I have deliberately not cited any PTAB E2E or CourtListener URL because there is no specific opinion to cite — inventing one would be fabrication.
• Date-eligibility notes for any future petition: the PGR window closed nine months after the 2020-03-10 grant (~2020-12-10), so PGR is time-barred; CBM is unavailable both by subject matter (this is a technical assay patent, not a "covered business method") and by the CBM program's sunset for new petitions. IPR is your vehicle, and given the claim-set's numeric/functional limitations, a § 103 obviousness attack combining the cited magnesium/cation LAL art with the LER literature is the natural theory.
• Bottom line for a defendant today: the patent is unadjudicated and fully intact. There is no PTAB win to cite and no canceled claims to hide behind; any defense must be built de novo, and any statement that "claims X–Y are dead" would be false on the current record.

I'll research the assignment record for US 10585097 before writing up the analysis.

Ownership Analysis — US 10585097 B2

"Bacterial endotoxin test for the determination of endotoxins"
App. 15/739,503 · PCT/EP2016/067896 · Priority 2015-07-28 · Filed 2016-07-27 · Granted 2020-03-10

Sourcing note (read first): I was able to retrieve the legal-events chain for this patent (Google Patents event log, which mirrors the USPTO assignment records), but I was not able to retrieve the underlying reel/frame numbers or correspondent-of-record fields in this session — the Assignment Center search interface is not directly reachable from my tools. Reel/frame and correspondent should be confirmed by direct lookup at assignmentcenter.uspto.gov and patents.google.com/patent/US10585097/en. I have not invented reel/frame numbers. The dates, conveyance types, and parties below are drawn from the recorded event chain; the reel/frame cells are marked unretrieved.

Inventors

Pattern note: The five inventors split cleanly 2 : 2 : 1 across three employer-side entities (Borstel institute, Roche Diagnostics GmbH, F. Hoffmann-La Roche AG). This is the signature of a joint research-and-development collaboration, not a drifting team: each inventor assigned to their own employer on the same day, and the employers then cross-assigned into the Roche group. There is no evidence of inventors departing within 12 months of filing — the inventors assigned rights to their employers in 2018, which is the normal duty-of-assignment flow, the opposite of an abandonment pattern.

Original assignee

On the issued patent: three co-assignees —

• Forschungszentrum Borstel, Leibniz Lungenzentrum (FZB) — a public Leibniz-Association research institute in Borstel, Germany (respiratory/lung research; LPS/endotoxin biochemistry is a core competency — the institute's Rietschel LPS work is cited throughout the specification itself).
• Roche Diagnostics GmbH (Penzberg, Germany) and Hoffmann-La Roche Inc. (U.S. subsidiary) — the Roche group.

Product embodiment: Yes, functionally. The claims are directed to an assay/handling method (Mg²⁺ addition → dilution → dialysis → LAL/BET) needed to validate endotoxin testing of Roche's own biologic pipeline (the specification builds its examples entirely on Rituxan®/MabThera®/Zytux® — rituximab, a Roche/Genentech product — and on the polysorbate-80 + sodium-citrate matrix of that product). This is an internal quality-control / regulatory-assay asset supporting a marketed monoclonal antibody, not a standalone licensing vehicle.

Primary line of business: Roche = global pharma/diagnostics operating company. Borstel = nonprofit research institute.

Current status: Both operating. Roche is a publicly listed, going-concern pharma (SIX: RO / OTCQX: RHHBY) with no bankruptcy history relevant here. Leibniz Lungenzentrum is an active state/federally funded research institute. There is no record of dissolution, Chapter 7, or Chapter 11 for either party.

Assignment timeline

All 2022-06 filing data and event dates below are from the recorded event chain. Reel/Frame: unretrieved in this session (see sourcing note); do not treat the absence as meaning no record exists.

• 2018-07-24 (executed) / recorded 2018-07-24 — Reel unretrieved/xxxx

  • Conveyance: Assignment (Assignment of Assignors' Interest)
  • Assignor: Zaehringer, Ulrich; Alexander, Christian (inventors)
  • Assignee: Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften
  • Correspondent: unretrieved
  • Context: Standard inventor→employer duty-of-assignment (institution-side).

• 2018-07-24 (executed) / recorded 2018-07-24 — Reel unretrieved/xxxx

  • Conveyance: Change of Name
  • Assignor: Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften
  • Assignee: "FOSCHUNGSZENTRUM BORSTEL LEIBNIZ LUNGENZENTRUM" (as spelled in the record — "Forschungszentrum" is misspelled in the assignee name of record)
  • Correspondent: unretrieved
  • Context: Internal institute renaming — administrative only; no change in beneficial ownership.

• 2018-07-25 (executed) / recorded 2018-07-25 — Reel unretrieved/xxxx

  • Conveyance: Assignment
  • Assignor: Deutschmann, Sven; von Wintzingerode, Friedrich (inventors)
  • Assignee: Roche Diagnostics GmbH
  • Correspondent: unretrieved
  • Context: Inventor→employer duty-of-assignment (Roche-diagnostics side).

• 2018-07-25 (executed) / recorded 2018-07-25 — Reel unretrieved/xxxx

  • Conveyance: Assignment
  • Assignor: Lang, Pierre (inventor)
  • Assignee: F. Hoffmann-La Roche AG
  • Correspondent: unretrieved
  • Context: Inventor→employer duty-of-assignment (Roche parent side).

• 2018-07-25 (executed) / recorded 2018-07-25 — Reel unretrieved/xxxx

  • Conveyance: Assignment
  • Assignor: Roche Diagnostics GmbH
  • Assignee: F. Hoffmann-La Roche AG
  • Correspondent: unretrieved
  • Context: Intra-group consolidation — pull diagnostics-side rights up into the Roche parent.

• 2018-07-25 (executed) / recorded 2018-07-25 — Reel unretrieved/xxxx

  • Conveyance: Assignment
  • Assignor: F. Hoffmann-La Roche AG
  • Assignee: Hoffmann-La Roche Inc. (U.S. subsidiary)
  • Correspondent: unretrieved
  • Context: Intra-group push-down to the U.S. operating subsidiary to align prosecution/ownership with the U.S. national-stage case.

• 2022-06-15 (executed) / recorded 2022-06-15 — Reel unretrieved/xxxx

  • Conveyance: Assignment
  • Assignor: Forschungszentrum Borstel, Leibniz Lungenzentrum
  • Assignee: Hoffmann-La Roche Inc.
  • Correspondent: unretrieved
  • Context: Consolidation — the institute's co-owner share is transferred to Roche's U.S. entity, leaving Roche as sole owner. Normally the closing step of a collaboration when the institute's research role ends.

No post-issuance assignment to any unrelated third party, licensing entity, or trust is recorded. No security agreement, license recordation, or release appears in the chain. If a security-interest or license record exists it did not surface in the event log and would need to be checked directly on Assignment Center.

Timeline diagram

timeline
    title Ownership of US 10585097
    2015 : Priority EP application filed
    2016 : PCT filed
         : US national stage entered
    2018 : Inventors assign to employers
         : Borstel institute renamed
         : Roche group consolidates interest
    2020 : Patent granted
    2022 : Borstel transfers share to Roche Inc

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. Every assignee is a named operating entity: Roche Diagnostics GmbH, F. Hoffmann-La Roche AG, Hoffmann-La Roche Inc., and the Leibniz Lungenzentrum. No "IP / Holdings / Ventures / Licensing" suffix, no registered-agent-only address, no single-purpose Delaware/Texas LLC appears anywhere in the chain (records dated 2018-07-24 through 2022-06-15).

2. Known asserter in the chain — Not present. No assignee matches Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, or any Spangenberg entity. The chain begins and ends inside the Roche corporate group plus a public research institute.

3. Repeat correspondent across the chain — Unclear / cannot be assessed. The correspondent-of-record field was not retrievable in this session, so I cannot confirm whether one attorney/firm handled all six 2018 recordings and the 2022 recording. This is precisely the field to pull next at Assignment Center — the 2018 cluster (five recordings in two days) plus the 2022 transfer would be expected to share a single Roche-side IP counsel, but I will not assert that without the record.

4. Cascading transfers — Not present as an NPE signal. There is a cluster (five recorded events across 2018-07-24/25), but each is either an inventor→employer duty-of-assignment, a change of name, or intra-Roche-group consolidation — the ordinary housekeeping of a multi-party collaboration. No chained LLC-to-LLC hops, no shared anonymous addresses, no <24-month sequence of unrelated assignees. This clusters as internal reorg, not cascade.

5. Pre-litigation transfer — Not present. I found no infringement suit on US 10585097, and the 2022-06-15 transfer (Roche's own subsidiary taking the last co-owner share) predates nothing relevant — it extends from founding, not a litigation deadline. No pre-suit clean-up transfer to a litigation vehicle.

6. Bankruptcy fire-sale — Not present. Neither assignor/assignee is in bankruptcy. Roche is a going concern; the Leibniz institute is publicly funded. No Chapter 7/11 sale of this asset.

7. Privateering — Not present. No transfer from an operating company to an NPE asserting on its behalf. The direction of travel is the opposite: rights are being pulled into the operating company (2022-06-15), not pushed out to an asserter.

8. Defensive aggregator (anti-NPE) — Not present. The chain terminates at Hoffmann-La Roche Inc., an operating company — not RPX, AST, LOT, Unified Patents, or OIN.

Verdict

Operating-company assertion — with the explicit caveat that the "assertion" half is unproven: the patent is an operating-company quality-control asset, not an NPE play. The chain runs inventor → employer assignments (2018-07-24/25), a change of name (2018-07-24), intra-Roche consolidation (2018-07-25), and finally the institute's co-owner share transferred to Hoffmann-La Roche Inc. on 2022-06-15, leaving the Roche group as sole owner. No shell LLC, no known asserter, no defensive aggregator, no recorded bankruptcy, and no infringement suit on this patent that I could find — so I flag that if the analyst's rubric requires an actual suit to score "operating-company assertion," this should instead be recorded as non-asserted operating-company ownership, not an NPE.

Verification: USPTO Assignment Center (search patent 10585097 to pull the reel/frame and correspondent fields I could not retrieve) · Google Patents US10585097 · family member US11360085B2 ("Bacterial endotoxin test for the determination of endotoxins") should be checked for a parallel chain.

I'll research the prior art citations for US Patent 10,585,097. Let me search for the patent's citation records.

Let me search more specifically for the patent's front-page citations and its examination record.

I found the Justia citation list. Let me retrieve the full reference list from Justia and Google Patents.

US 10,585,097 — Prior-Art Citations Analysis

Two verification caveats first (read before the analysis)

1. Patent number confirmed literally. USPTO/Justia/Google Patents records for US 10,585,097 B2 ("Bacterial endotoxin test for the determination of endotoxins," app. US 15/739,503; PCT/EP2016/067896; priority EP 15178683.7, 2015‑07‑28) were located. I did not substitute any similar number (e.g., 11,050,097).

2. The citation list I retrieved is TRUNCATED, and I could not obtain the granted claims text. The authoritative patent text supplied in this task ends before the claims. The best citation source I reached was Justia's "Referenced Cited" block for US 10,585,097, which itself cut off (the U.S.‑patent portion jumps from US 4,680,177 of 1987 to a 2012 CN document, so intermediate U.S. patents are missing). Everything below is drawn only from what I could actually retrieve; I flag gaps rather than fill them. Claim mapping is to the inferred claim concepts (Mg²⁺ addition → dilution → dialysis → LAL), not to verbatim claim language.

References retrieved from the US 10,585,097 record ("Referenced Cited")

A. U.S. patent documents (front‑page citations)

⚠️ I could not verify the disclosures of these four older U.S. patents from available sources. I will not fabricate their titles or contents. They sit in the "Background/analytical methods" bracket and, on their face, are not §102 art for the ordered Mg²⁺→dilution→dialysis combination.

B. Foreign patent documents (front‑page citations)

C. Non‑patent literature (the substantively relevant citations)

These are the references that actually bear on the claim elements.

§102 assessment (35 U.S.C. § 102)

Bottom line: On the record I could retrieve, none of the cited references anticipates any independent claim. The reason is structural, not a matter of degree:

• Anticipation under §102 requires a single reference disclosing every element of the claim, arranged as claimed. (MPEP 2131.)
• The independent claims are directed to an ordered combination — (a) add Mg²⁺ → (b) dilute → (c) dialyze at pH 5.7–8.0 → (d) LAL/BET — and the specification itself stresses that "the specific combination and sequence of steps (a) to (c)" is what overcomes LER, citing a reference example in which the reversed order (dilution → dialysis → Mg²⁺) failed.
• The strongest single references each supply at most one element:
  • Tsuji 1983 / Sourek 1978 → step (a) Mg²⁺ only.
  • Thermo Fisher handbook 2009 → step (c) dialysis only.
  • Routine dilution ("MVD") (discussed in the patent's own Background) → step (b) only.
  • Williams 2013, Chen & Vinther 2013, Hughes 2015 → the LER problem, not the solution.

No reference combines Mg²⁺ + dilution + dialysis, and none does so in the claimed order. Therefore these are properly characterized as §103 obviousness‑type references (single‑element teachings that could be combined), not §102 anticipation references.

References I could not evaluate for §102 (do not treat as cleared): US 2,123,198; US 4,096,091; US 4,124,509; US 4,680,177; CN 102841205; CN 102901726; EP 0513361. I did not retrieve their disclosures, so I cannot affirm or deny §102 relevance for these — only that they are not, on their face, full‑combination art.

What is missing / recommended verification

• The complete front‑page [56] citation list. The Justia block was truncated; U.S. patents between 1987 (US 4,680,177) and 2012 (CN 102841205) are absent. Retrieve the full [56] "References Cited" from the USPTO PatentCenter/Global Dossier record or the granted‑patent PDF (patentimages) to capture every U.S. and foreign patent citation.
• The literal granted claims. The authoritative text you supplied cut off before the claims. The §102 element‑by‑element mapping above is keyed to the inferred claim concepts (from the specification's "the present invention relates to…" statements). Confirm claim wording, count, and dependencies against the granted claims before relying on this mapping.
• The examiner's applied art. To see which citations were actually used in rejections (and any 102/103 characterizations), pull the file history for US 15/739,503.

If you'd like, I can run targeted lookups on the four unverified U.S. patents (Parfentjev '198; Hopkins '091; Iijima '509; Gray '177) and the two CN documents to complete the element‑by‑element table.

I'll research the prior art landscape for this patent, including the references cited on its face and analogous LER/BET prior art.

I have the granted claims and the "Referenced Cited" prior-art list. Let me characterize the key references and confirm claim wording.

Obviousness Analysis — US 10,585,097 B2 under 35 U.S.C. § 103

Analysis date: April 26, 2026. Patent interpreted literally as US 10,585,097 B2.

0. Reconciliation with the previously generated sections

• The earlier Patent summary flagged that the claims could not be quoted because the supplied text was truncated before the claims. That gap is now partially resolved: I retrieved granted claim text (claims 1–52) from a third-party rendering of the Justia record for this patent (https://patents.justia.com/patent/10585097), which also supplies the "Referenced Cited" prior-art list that I use as "the Prior Art section of this page."
• ⚠️ Contradiction/limitation to flag: Justia's HTML renders several claims (notably 16, 30, 37) with the "wherein the antibody is a monoclonal therapeutic antibody" clause displaced from its proper position, and the preamble of claim 1 is not fully visible. The literal wording must be confirmed against USPTO PatentCenter for application 15/739,503. My element mapping below is to the substance of the claims, not to verified quotation.
• The Litigation summary (none found for US 10,585,097) is consistent with what I found here. For the record, search results surfaced a PTAB proceeding in the endotoxin-testing art generally — Charles River Laboratories, Inc. v. Seikagaku Corporation, PGR2025-00023 (exhibit pages hosted at ptacts.uspto.gov) — but I did not verify that US 10,585,097 is at issue there, and I do not attribute it to this patent.

1. Legal framework, key dates, and claim scope

Claim structure (per the Justia rendering). Independents appear to be claims 1, 2, 16, 30, 37, with dependents 3–15, 17–29, 31–36, 38–52. Substance:

• Claim 1 — method for determining bacterial endotoxin in an antibody‑containing sample, in order: (a) adding magnesium ions (MgCl₂ per claim 31); (b) diluting; (c) dialyzing at pH 5.7–8.0 against an endotoxin‑free aqueous solution; (d) determining endotoxin by a LAL assay.
• Claims 2 / 16 / 30 — analogous methods framed as reducing endotoxin masking / overcoming LER and rendering the sample reactive to factor C in the LAL cascade (claim 2 apparently adds the "endotoxin‑binding proteins … amphiphilic compound combined with citrate or phosphate buffer" limitation — the same limitation that appears in the asserted independent claim of the continuation US 11,360,085 B2 per https://mtec-sc.org/patents/US-11360085-B2).
• Claim 37 — "method for preparation of a sample … for a LAL assay" with steps (a)–(c) plus (d) determining, i.e., effectively duplicative of claim 1 with a different preamble.
• Dependents add: antibody = therapeutic/monoclonal (17), rituximab/anti‑CD20 (6, 21, 41), polysorbate 80 (3, 18, 38), citrate buffer (4, 19, 39), 25 mM Na‑citrate + 700 mg/L PS80 at pH 6.5 (5, 20, 40), Mg²⁺ 25–75 mM / 2.5–75 mM (7, 22, 42), Tris/HCl 10–50 mM pH 6–9 dilution (8, 23, 43), 1:10 dilution (9, 24, 44), dialysis pH 6–8 (10, 25, 45), 24 h at RT (11, 26, 46), 10 kDa MWCO (12, 27, 47), cellulose acetate membrane (13, 28, 48), two water changes (14, 29, 49), and an LER positive control shaken 60 min–2 h (15, 50).

Claim-construction note that widens the § 103 exposure: the specification is internally inconsistent on dialysis pH — 5.7–8.0 vs 5.7–9.0 (see the earlier summary and, e.g., the AU/EP family text at https://patentimages.storage.googleapis.com/93/ea/24/09554d3dd36130/AU2016298598B2.pdf). The broader reading (up to pH 9.0) is more squarely met by the prior art discussed below.

2. Person having ordinary skill in the art (POSITA)

A POSITA here is a scientist (M.S./Ph.D. in microbiology, biochemistry, or pharmaceutical sciences, or B.S. plus 3–5 years) in biologics quality control / endotoxin testing, familiar with USP <85>, Ph. Eur. 2.6.14, and JP 4.01; with the gel‑clot, turbidimetric, and chromogenic LAL formats; and with routine sample‑preparation unit operations (dilution to the maximum valid dilution, pH adjustment, heat/freeze treatment, detergent removal, ultrafiltration/dialysis, ion supplementation). This is a mature, highly codified, method‑development art — a fact that materially lowers the inventive‑step bar. (Cf. the survey of the field in American Pharmaceutical Review, https://www.acciusa.com/pdfs/supplements/Endotoxin%20Detection%20Part%20VIII/3_Functional%20Challenges%20Part1%20-%20APR%20Sup%20VIII.pdf.)

3. The prior art of record and what each reference supplies

4. Obviousness grounds

Ground 1 (primary, strongest): Chen & Vinther 2013 + Hughes 2015 + Williams 2013 + Tsuji & Steindler 1983 + Pierce Dialysis/Detergent‑Removal Handbook 2009 (+ Piotrowicz 1986 for step (d))

Every element is disclosed or taught:

Motivation to combine (KSR/lead‑compound logic):

1. A recognized, unsolved problem with regulatory pressure. Hughes 2015 (FDA perspective) expressly states LER is unresolved and that the conventional approach — spike a diluted sample at the NIC — "fails to recognize that components of the sample matrix … potentially impact the LAL reactivity of endotoxins in undiluted product samples." That is a direct teaching away from the conventional single tool (dilution) and thus an explicit motivation to seek additional preparative steps.
2. A finite, known universe of sample‑preparation tools. The art of record enumerates and tests exactly the candidate tools a POSITA would try: dilution, pH adjustment, heat, freeze, protease, detergent removal, salt/buffer removal (dialysis/desalting), and ion supplementation. Williams 2013 itself walks through this menu, i.e., it supplies the "try the known options" motivation that KSR holds sufficient.
3. The two "physical‑chemistry" steps are known, routine, and mechanism‑consistent. Chen/Williams attribute LER to a chelating buffer (citrate) plus a surfactant removing/disaggregating LPS. Tsuji 1983 teaches that divalent Mg²⁺ is required/beneficial for LAL reactivity, with a 50–65 mM optimum — which a POSITA would immediately apply to a citrate‑chelated matrix (the specification itself explains the mechanism: "Mg²⁺ is complexed by the chelating buffer," US 2018/0188249 A1 ¶[0562]). And the Pierce handbook teaches that dialysis removes the detergent and buffer while the ~150 kDa antibody is retained. Combining "re‑supply the chelator‑consumed cation" + "remove the surfactant/buffer by dialysis" is the paradigm of a predictable combination of prior‑art elements to achieve the known purpose of restoring assay sensitivity (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007)).
4. Reasonable expectation of success. Tsuji reports a 10–30× sensitivity gain at exactly the claimed Mg range and pH range; the Pierce handbook reports quantitative removal of salts/detergents by dialysis as a routine, validated operation. Nothing in the art taught that these steps would be inoperative in an antibody matrix.

Result for Ground 1: claims 1, 2, 16, 30, 37 and dependents 3–14, 17–29, 31–36, 38–49 would have been obvious. The generic claims stand or fall on the ordered three‑step preparation plus LAL readout; each step and each numeric limitation has a direct prior‑art correlate.

Ground 2: Chen & Vinther 2013 + Williams 2013 + Hughes 2015 + Petsch 1998 + Tsuji 1983 (attacking the "endotoxin‑binding proteins / masking" limitations of claim 2 and of the continuation's claim 1)

Petsch 1998 establishes that IgG–endotoxin binding masks LAL reactivity and that unmasking is achievable. Chen/Williams distinguish protein masking from formulation LER and caution that a real‑world sample can present both ("the interplay of the two phenomenon may confound clear‑cut mechanism determinations," Williams 2013). A POSITA seeking to overcome masking in a mAb product would therefore be motivated to combine a protein‑unmasking measure with a formulation‑directed measure (Mg²⁺ + dilution + dialysis). This ground is specifically useful against the claim language tying the effect to "endotoxin‑binding proteins present in the sample and/or formulation ingredients … amphiphilic compound combined with citrate buffer or phosphate buffer" (as recited in US 11,360,085's independent claim per https://mtec-sc.org/patents/US-11360085-B2).

Ground 3: Tsuji 1983 + Williams 2013 + Pierce handbook 2009 (no LER‑specific reference required)

Even if a tribunal were to credit the patentee's framing that "nothing is known about the physico‑chemical mechanisms of the LER effect," § 103 does not require the mechanism to be known — only that the claimed subject matter as a whole have been obvious. Tsuji 1983 alone teaches that a citrate/parenteral matrix assay is enabled by Mg²⁺ at 50–65 mM and pH 6–8 and ties this to parenteral product testing and maximum valid dilution; Williams 2013 provides the LER problem statement and dilution/pH/protease menu; the Pierce handbook provides dialysis for detergent removal. This ground renders at least claims 1, 7, 9, 10, 12, 13, 16, 22, 24, 25, 27, 28, 30, 37, 42, 44, 45, 47, 48 obvious on a two‑ or three‑reference combination.

Ground 4: Any of the above + the known rituximab product formulation (claims 5, 6, 20, 21, 40, 41)

Rituximab's commercial formulation is publicly documented in the specification itself and in the art (25 mM sodium citrate, pH 6.5, 700 mg/L polysorbate 80, 154 mM NaCl — see US 2018/0188249 A1 ¶[0056]-region text at https://patents.justia.com/patent/20180188249). Using a known, commercially marketed, injectable mAb subject to mandatory BET testing as the sample of a BET method is not inventive; it is the intended use of the method. Claims 5/20/40 (specific formulation) and 6/21/41 (rituximab) are accordingly obvious over any of Grounds 1–3 in view of the product's public labelling.

Ground 5: LER positive control (claims 15, 50)

Chen & Vinther 2013 and Hughes 2015 disclose that LER develops over time (days; faster at RT) in undiluted spiked product. USP <85>'s positive product control and the compendial "test for interfering factors" (spike‑and‑recovery, 50–200%) were standard. Preparing a positive LER control by spiking an aliquot and holding/shaking it 60 min–2 h is the routine implementation of the documented time‑dependence. Claims 15 and 50 are obvious over Chen & Vinther 2013 + Williams 2013 + USP <85>.

5. Anticipated patent‑owner rebuttals and how they fare

6. Bottom line

• Independent claims 1, 2, 16, 30 and 37 are, on the strongest reading, obvious under § 103 over Chen & Vinther 2013 + Williams 2013 + Hughes 2015 (problem + motivation + tool menu), in view of Tsuji & Steindler 1983 (Mg²⁺, 50–65 mM; pH 6.0–8.0), Thermo Fisher Pierce Dialysis/Detergent‑Removal Handbook 2009 (dialysis to remove buffer/detergent; MWCO and membrane selection), and Piotrowicz 1986 / USP <85> (LAL readout). Petsch 1998 and Sourek 1978 are useful secondary references, and Petsch is the key reference for the "endotoxin‑binding proteins" limitation.
• Numeric/parameter dependents (7–14, 22–29, 42–49) are obvious for the same reasons — each range is either taught by Tsuji (Mg, pH), by the Pierce handbook (MWCO, membrane chemistry, water changes, duration), or is routine optimization of a known method to achieve a known result.
• Product‑specific dependents (3–6, 17–21, 38–41) are obvious given the publicly documented rituximab/PS80/citrate formulation.
• LER‑control dependents (15, 50) are obvious over Chen & Vinther 2013 + standard USP <85> positive controls.
• The patentee's best (and non‑trivial) rebuttal is unexpected synergy / criticality of order, supported by FIGs. 11, 12 and 16. Its strength is materially weakened by the same record's showing that Mg²⁺ + 1:10 dilution without dialysis already achieved 50–80% recovery at the 5.0 EU/mL spike level, and by the KSR line on predictable sequencing of routine analytical unit operations.

7. Explicit uncertainties (do not over‑read this analysis)

1. Claim text is from a third‑party rendering (Justia), not from the truncated authoritative text supplied to me; preambles of claims 1, 2, 16, 30 and 37 are incompletely legible in that rendering. Confirm on USPTO PatentCenter before relying on any specific limitation phrasing.
2. Contents of several face‑cited references were not verified by me: US 2,123,198; US 4,096,091; US 4,124,509; US 4,680,177; EP 0 513 361; CN 102841205; CN 102901726; Sofer 1984; and the three Chinese‑language NPL items (Yang 2002, Liu 2008, Pei 2014). I characterized them only by title/date/field, and I did not auto‑correct the anomalous "EP 0 513 361 — Nov. 1922" date.
3. Hughes 2015 is treated as § 102(a)(1) art on the assumption of a Mar./Apr. 2015 publication date, which precedes the 2015‑07‑28 priority date — verified only to the extent that the citation appears in the record and the journal issue is Mar./Apr. 2015.
4. No litigation/PTAB record was identified for US 10,585,097; the PGR2025‑00023 (Charles River v. Seikagaku) material surfaced in searches is not attributed to this patent.
5. This is a technical/legal‑analytical assessment, not legal advice; a validity opinion would require the full prosecution histories (US and EP), the EESR's X/Y citations with the examiner's reasoning, and any post‑grant challenges.