US 5545806

I'll search for this specific patent number and related litigation information.

Let me check for CAFC litigation and get the claim text.

Let me try to retrieve the actual claim text and check for any 2026 CAFC activity specifically referencing this patent.

US Patent 5,545,806 — Analyst Summary

Caveat up front: I retrieved this from open patent data (Google Patents, RPX/insight, FreePatentsOnline, uspto.report, everypatent). I did not obtain a formal USPTO PatentCenter/PEDS record, a certified copy of the claims, or any CAFC docket sheet directly. Where the record is fragmentary I say so.

Bibliographic data

Literal-record note (do not auto-correct): the title as published in the database record contains the spelling "Ransgenic" (missing the "T"). I am reproducing it verbatim per your strict-ID rule. Likewise, the application number is US 07/990,860 — not to be conflated with the sibling GenPharm patents (5,569,825; 5,625,126; 5,633,425; 5,661,016; 5,770,429; 5,814,318), which are separate numbers with separate specifications.

Abstract (as recorded)

The invention relates to transgenic non-human animals capable of producing heterologous antibodies and transgenic non-human animals having inactivated endogenous immunoglobulin genes. In one aspect, endogenous immunoglobulin genes are suppressed by antisense polynucleotides and/or by antiserum directed against endogenous immunoglobulins. Heterologous antibodies are encoded by immunoglobulin genes not normally found in the genome of that species. In one aspect, one or more transgenes containing sequences of unrearranged heterologous human immunoglobulin heavy chains are introduced into a non-human animal, forming a transgenic animal capable of functionally rearranging transgenic immunoglobulin sequences and producing a repertoire of antibodies of various isotypes encoded by human immunoglobulin genes. Such heterologous human antibodies are produced in B-cells which are thereafter immortalized (e.g., fused with a myeloma) to produce a monoclonal heterologous antibody. The invention also relates to heavy and light chain immunoglobulin transgenes for making such animals, and to methods and vectors for disrupting endogenous immunoglobulin loci.

Independent claim — plain language

I recovered the full text of claim 1 (the independent method claim) but not a verified complete claim set; dependent claims 13 and 14 appear in fragmentary form (13 recites a NotI fragment/pHC1 insert and expression of human mu and human gamma‑1 chains in serum; 14 recites collecting serum containing human gamma‑1 chains). Uncertainty flagged: I cannot confirm the total claim count, nor rule out additional independent claims, from the sources retrieved.

Claim 1 — A method for producing heterologous immunoglobulins from a transgenic mouse:

1. Contact the transgenic mouse with a pre‑selected antigen;
2. the mouse's genome contains germline copies of at least one transgene having human VH, human D, and human JH segment genes;
3. the transgene undergoes isotype switching in vivo from a transgene‑encoded mu (IgM) isotype to a downstream human gamma (IgG) isotype;
4. a "minilocus" limitation: the number of nucleotides between the transgene's mu and gamma gene segments is less than the corresponding distance between human mu and that human gamma isotype in the human germline; and
5. collect the heterologous human gamma immunoglobulins that bind the pre‑selected antigen.

In plain terms: immunize a mouse carrying a compacted, unrearranged human heavy‑chain "minilocus" transgene; the transgene must actually class‑switch in vivo from IgM to IgG; then harvest the antigen‑specific human IgG. The novel hook is the requirement that the transgene be physically shorter (fewer intervening nucleotides between Cμ and the gamma constant region) than the natural human germline spacing — a construction designed to make switching feasible in a small transgene.

CAFC 2026 dockets — search result

I found no 2026 Federal Circuit docket, opinion, order, or appeal referencing US 5,545,806. My searches returned only:

• 2026 CAFC material unrelated to this patent (e.g., Yechezkal Evan Spero v. Mercedes‑Benz USA, Nos. 2025‑1306/1307/1473, Rule 36 judgment May 14, 2026; Contour IP Holding v. GoPro, No. 2026‑2012),
• historical academic/empirical data showing the patent was asserted in litigation by GenPharm International (plaintiff) against Abgenix (defendant) in an earlier era (c. 2010 survey data), and
• numerous later patents merely citing 5,545,806 as prior art.

This is consistent with the patent having expired in 2013, which makes live 2026 infringement appeals implausible. Uncertainty flagged: absence of a search hit is not proof of absence. Court dockets are not fully indexed by general web search, and I did not query PACER, the CAFC CM/ECF docket system, or USPTO PatentCenter directly. If you need a definitive negative, the authoritative check is the CAFC docket search plus USPTO PatentCenter for the application number 07/990,860.

Sources

• Google Patents record (bibliographic, priority chain, expiry): https://patents.google.com/patent/[US5545806A](/patent/US5545806A)/en
• Abstract and claim 1 text (RPX Insight): https://insight.rpxcorp.com/patent/US5545806A
• Inventors/assignee/filing date/US class: http://www.everypatent.com/comp/pat5545806.html
• Fragmentary dependent-claim text (claims 13–14): https://uspto.report/patent/grant/5545806
• Litigation survey listing GenPharm / 5545806 / Abgenix: Nature Biotechnology supplementary data, https://static-content.springer.com/esm/art%3A10.1038%2Fnbt0410-325/MediaObjects/41587_2010_BFnbt0410325_MOESM34_ESM.pdf
• 2026 CAFC orders (unrelated, checked for name/number match): https://cafc.uscourts.gov/opinions-orders/25-1306.RULE_36_JUDGMENT.5-14-2026_2693760.pdf

I'll search for litigation involving US patent 5545806.

Let me search litigation-specific sources.

Bottom line

I was unable to verify any litigation — district court, CAFC, ITC, or otherwise — in which US 5,545,806 was asserted or adjudicated. I found no case caption, docket number, jurisdiction, or filing date for such a suit. Because you asked me not to fabricate and to treat identifiers literally, I am reporting that as a null result rather than supplying anything I cannot ground.

Patent being searched (for exact-match control)

• Number: US 5,545,806 ("Ransgenic non-human animals for producing heterologous antibodies" — title as printed)
• Inventors: Nils Lonberg; Robert M. Kay
• Assignee of record: Genpharm International Inc
• Application: US 07/990,860; filed 1992-12-16; priority 1990-08-29; granted 1996-08-13
• Legal status per Google Patents: Expired – Lifetime (anticipated expiration 2013-08-13)
• Source: https://patents.google.com/patent/US5545806/en

Note: I did not substitute results for similar numbers (e.g., US 5,545,807, US 5,569,825, US 5,625,126, US 5,633,425, US 5,661,016, US 5,770,429, US 5,789,650, US 5,814,318, US 5,874,299 — all Lonberg/Kay-family or Surani patents frequently cited alongside it). Those appeared repeatedly in the search results as citations, not as litigation records, and I excluded them.

The one lead found, and why it is not confirmable

A supplementary data table to a 2010 Nature Biotechnology paper lists US 5,545,806 in connection with litigated patents, associating the number with:

• Plaintiff column: GenPharm International Incorporated
• Defendant column: Abgenix Incorporated

Source: https://static-content.springer.com/esm/art%3A10.1038%2Fnbt0410-325/MediaObjects/41587_2010_BFnbt0410325_MOESM34_ESM.pdf

I am not reporting this as a case, for three reasons:

1. The table provides only a patent number and party names. It contains no court, no case number, no filing date, and no outcome — nothing that satisfies your requested fields.
2. The named parties are internally incoherent as an adversarial pairing. GenPharm International is the original assignee of record on US 5,545,806, and Abgenix is the entity that succeeded to GenPharm's business (GenPharm renamed itself Abgenix in 1999). A "GenPharm v. Abgenix" infringement suit is not a plausible caption, which suggests the table is either coding a corporate-succession event, an internal portfolio transfer, or contains a data artifact. I cannot resolve which.
3. I could not corroborate that entry in any independent litigation source (Unified Patents litigation portal, CAFC opinions, PACER-derived dockets, or court-filing aggregators).

The USPTO assignment record visible on the Google Patents page likewise shows only the 1993 assignment from inventors Kay and Lonberg to GENPHARM INTERNATIONAL, INC. — an assignment, not litigation.

What I searched

• "US patent 5545806 litigation"
• "5545806" patent lawsuit Genpharm
• "5,545,806" patent infringement lawsuit — returned no results
• portal.unifiedpatents.com litigation "5545806"
• "5,545,806" Abgenix v. Medarex / CAFC case

The last two queries returned only patent-family citation lists (mostly foreign-language specifications citing the number as background art), not docket records. One search exceeded the available step budget before I could return results.

Honest statement of uncertainty

• I do not know of any confirmed litigation involving US 5,545,806, and I am not asserting there is none. My inability to find one is not proof of absence — the Unified Patents litigation case list and PACER are not fully indexed by the search tools available to me, and a suit filed and resolved before broad docket aggregation existed could be indexed only under the patent's other family members.
• This patent's commercial significance sits with the human-antibody transgenic-mouse programs (GenPharm/Abgenix "XenoMouse" and the Medarex "HuMAb" line, which was licensed from GenPharm). Industry disputes in that space are the place I would expect an assertion on this family to appear, but I have no verified case number tying any such dispute to US 5,545,806 specifically.

Recommended verification steps

1. Query the Unified Patents litigation case list directly for the exact string "5545806": https://portal.unifiedpatents.com/litigation/caselist
2. Run a PACER docket search / CourtListener RECAP search on "5545806" and on "5,545,806".
3. Check the CAFC opinion database for the exact patent number.
4. Query the USPTO Patent Center "Litigation" tab and the USPTO Assignment database for US 5,545,806 to trace ownership through the GenPharm → Abgenix → Amgen chain, which may reveal the correct party names for any suit.
5. If the Nature Biotechnology table entry matters, contact the authors (corresponding author of Nat. Biotechnol. 28:325, 2010) to obtain the underlying case citation; the supplementary table alone is insufficient evidence.

If you can confirm a case number or court, I can pull the specifics and populate the plaintiff/defendant/jurisdiction/filing-date/status fields you requested.

I'll verify the ODP structured data with targeted searches before writing anything.

Let me run additional targeted checks — IPR databases, Unified Patents' portal, reexamination history, and the known GenPharm/Abgenix litigation.

Proceedings overview

Zero AIA trial proceedings on file. The USPTO Open Data Portal returns no IPR, PGR, or CBM proceeding naming US 5,545,806, and my independent searches surfaced no petition, institution decision, Final Written Decision, or Federal Circuit appeal involving this patent. Breakdown: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denied. The bottom-line defensive posture is unusual and, for a defendant, unusually strong — but not because the patent was tested at the PTAB. It is because the patent expired on 2013-08-13 (anticipated expiration, status "Expired - Lifetime" in the structured data), and because the two AIA channels that could have generated a rich record against it — PGR and CBM — were never legally available against it:

• PGR: unavailable. PGR under 35 U.S.C. § 321 applies only to patents with an effective filing date on or after 2013-03-16. This patent's priority date is 1990-08-29 (application 07/990,860 filed 1992-12-16), with a chain of CIP parents back to Ser. No. 07/574,748 filed 1990-08-29. Twenty-three years too early.
• CBM: unavailable. CBM review is limited to patents claiming data processing or other operations used in the practice, administration, or management of a financial product or service. A transgenic-mouse/immunoglobulin claim set (claims 1–14, all method claims) is not a covered business method patent.
• IPR: legally available from 2012-09-16 onward, available even against expired patents — and never filed.

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Proceedings on US 5,545,806

None.

There is no proceeding number to report. Consistent with the instruction not to invent proceeding numbers, I am reporting an empty set rather than a plausible-looking docket.

What I searched, and what came back:

One adjacent hit worth flagging so it isn't mistaken for a proceeding on this patent: in IPR2017-01129 (Inter Partes Review of U.S. Pat. No. 8,679,487, Case IPR2017-01129), Patent Owner's Exhibit List dated 2017-07-06 cites "Lonberg, N. and Kay, R.M., '[T]ransgenic Non-Human Animals for Producing Heterologous Antibodies,' U.S. Patent No. 5,545,806 (filed December 16, 1992...)" as a documentary exhibit. That is US 5,545,806 being used as a reference in someone else's IPR on an unrelated patent. It is not a challenge to 5,545,806, and it confers no estoppel and no claim-level holding on this patent. Proceeding link: https://www.docketalarm.com/cases/PTAB/IPR2017-01129/

Reexamination: I found no evidence of an ex parte reexamination, reexamination certificate, or inter partes reexamination of 5,545,806. I could not confirm this to a certainty from the sources available to me, and I flag it as unverified rather than assert it. If a reexam certificate exists, it would appear in the patent's file wrapper at https://patents.google.com/patent/[US5545806A](/patent/US5545806A)/en and on Patent Center.

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Strategic summary

Claim status. Because no claim was ever canceled or confirmed in an AIA trial, the claim set stands as issued: claims 1–14, all untested at the PTAB, none canceled. Claim 1 is the broad method claim ("A method for producing heterologous immunoglobulins from a transgenic mouse, the method comprising: contacting said transgenic mouse with a pre-selected antigen... wherein the transgene undergoes isotype switching from a transgene-encoded mu isotype to a transgene-encoded downstream human gamma isotype in vivo... and collecting heterologous human gamma immunoglobulins which bind to said preselected antigen"). Claims 3–13 add structural/transgene limitations (the pHC1 NotI insert, VH251/VH105, DIR2, the 5.3 kb HindIII γ1 switch fragment, etc.). Note the claim set is method claims only — there is no composition or animal claim in this particular patent, which matters if you are being accused of making or using a transgenic animal rather than practicing the immunization/collection method.

Estoppel landscape. There is none to navigate. Section 315(e)(2) estoppel attaches only to a petitioner that received a Final Written Decision, and no FWD exists. No third party is estopped, and no prior-art ground has been "used up." If a defendant today wanted to mount a § 102/§ 103 defense, every printed-publication ground remains available in district court. Practically, though, the better framing is not "which art survives estoppel" but "why litigate validity at all" — see below.

Pattern signals. No serial petitioner, no defensive aggregator (Unified Patents, RPX, etc.) in the chain, and no patent-owner appeal activity, because there was no proceeding to appeal. The litigation history runs the other direction: GenPharm International sued Abgenix, Inc., a Cell Genesys subsidiary, in the mid-1990s asserting this patent alongside US 5,569,825, per contemporaneous trade reporting ("GenPharm Receives U.S. Patents for Mice Producing Human Antibodies; Sues Cell Genesys Subsidiary"). That was a district court infringement action, not an AIA proceeding, and I do not have a verified disposition for it — I am flagging it rather than characterizing the outcome. Ownership has since moved through the Medarex → Bristol-Myers Squibb lineage; the '806 patent is cited extensively as foundational art in the HuMAb/XenoMouse literature but was never itself put on trial at the Board.

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Recommended next steps

1. Lead with expiration, not with PTAB. The patent expired 2013-08-13. Under 35 U.S.C. § 286 there is a six-year lookback on damages, so a demand letter served in 2026 can reach, at most, conduct from roughly 2020 onward — and there can be no infringement at all after the expiration date absent an intervening unexpired reissue or continuation. Before engaging any validity argument, demand from the asserting party (a) the expiration date they are relying on, (b) the specific accused acts, and (c) the dates of those acts.

2. No PTAB link to cite, because there is no FWD. There is no institution decision or Final Written Decision to quote or link. If opposing counsel implies the patent was "upheld by the PTAB" or "survived IPR," that is not accurate — it was never challenged. The correct characterization is that the patent was never tested in an AIA trial. Cite the patent's PTAB record page (https://patents.google.com/patent/US5545806A/en, "PTAB proceedings" tab, empty) and PTAB E2E (https://ptacts.uspto.gov/ptacts/) for verification.

3. If you need a validity fallback anyway (e.g., a licensee or indemnitor insists, or the assertion targets pre-2013 conduct), the affirmative defenses are § 102/§ 103 on the 1990–1992 priority art — Bruggemann et al., Bucchini et al., Goodhart et al., and the WO 90/04036 / WO 91/00906 / EP 0315062 references that already appear on the '806 face — plus the § 112 written-description and enablement attacks on the "less than the number of nucleotides... in the human germline" limitation added during prosecution. None of these were ever adjudicated at the Board, so a § 315(e)(2) estoppel analysis is unnecessary: nothing is barred.

4. Verify the negative on ODP once more at the moment of reliance. The structured block states ODP returned no proceedings "as of the most recent ingest," and my searches agree. Because patents this old rarely generate new petitions and this one is expired, I would expect the negative to hold — but the absence is a data artifact worth re-confirming at the time you file, not a legal conclusion. The absence of PTAB activity here is not the usual "well-asserted patents eventually attract IPRs" signal; it is explained by expiration plus the unavailability of PGR and CBM. Do not read it as evidence that the claims are robust.

Reproducibility note: the negative finding above rests on the structured ODP block supplied in the prompt plus web searches of Google Patents, the PTAB/docketalarm IPR corpus, and Unified Patents' portal. One search batch returned no results after I reached the tool-call limit; that omission does not change the conclusion, since the structured ODP data — the canonical source for AIA proceedings — is itself empty.

I'll research the assignment chain for US 5,545,806 across the USPTO assignment records and corporate-history sources.

Key lead: the original assignment reel/frame (006409/0573) surfaced. Let me trace the downstream chain and corporate history.

Critical correction surfaced: Medarex (not Abgenix) acquired GenPharm. Let me pin down the recorded post-issuance assignments and reel/frame numbers.

Assignment & Ownership Reconstruction — US 5,545,806

Scope note before the findings. I could not query the USPTO Assignment Center (assignmentcenter.uspto.gov) directly — it is a JavaScript application that does not render into my search results, and my assignment.uspto.gov queries returned no per-patent record for 07/990,860. What follows therefore rests on (a) the authoritative full text supplied in the prompt, whose Google Patents legal-events block shows exactly one reassignment event, and (b) a structured third-party mirror of the USPTO assignment record. I recovered only one reel/frame. I am not inventing the missing links.

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Inventors

Pattern check — no anomaly. Both inventors were in-house to the assignee and both assigned to GenPharm in the same instrument (Reel 006409/0573, executed 1993-01-28), roughly three months after the 1992-12-16 filing and seven months before the 1993-08-13… i.e. well before the 1996-08-13 grant. There is no evidence of inventors departing the assignee within 12 months of filing, no inventor-retained rights, and no separate inventor-to-third-party recordings. This is the ordinary "employee inventors assign to employer" pattern and is the antithesis of the pre-fire-sale signal.

(Unverifiable detail: neither inventor's employment contract or departure date is in the record I could retrieve. I make no claim about their later careers.)

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Original assignee

GenPharm International, Inc., a California corporation, Mountain View, CA (per the 1993 assignment document, which states the assignee's state of organization).

• Primary line of business: transgenic-animal biotechnology — specifically the HuMAb-Mouse, a mouse engineered to produce fully human-sequence antibodies. Founded 1989; the company also ran a European arm that produced "Herman" the transgenic bull.
• Did it ship a product embodying the claims? No marketed therapeutic. GenPharm's asset was the platform and its out-licenses, not a drug. Its revenue model was collaborations and licenses (Eisai, Centocor, LeukoSite) plus patent assertion. Critically for this analysis, asserting the transgenic-mouse patents was a line of business — in 1994 Cell Genesys sued GenPharm for trade-secret misappropriation, GenPharm's IPO was shelved, and after its own patents issued in late 1996/early 1997 GenPharm counter-asserted against Abgenix and Cell Genesys. That is operating-company patent enforcement against a competitor, not NPE behavior.
• Current status: No longer exists as an independent company. Acquired by Medarex, Inc. on 1997-10-21 for up to ~$65M in Medarex stock, becoming a wholly owned Medarex subsidiary (not dissolved — Medarex filings as late as the 2000s still refer to "Medarex, Inc. and its wholly-owned subsidiary GenPharm International, Inc."). Medarex was in turn acquired by Bristol-Myers Squibb (deal announced 2009; Medarex operations now "part of Bristol-Myers Squibb Company" per FibroGen's SEC disclosure). No bankruptcy, no Chapter 7/11, no assignment for the benefit of creditors appears anywhere in the record.

Correction to the earlier sections — flagging explicitly as required. The previously generated Litigation summary asserted that "Abgenix is the entity that succeeded to GenPharm's business (GenPharm renamed itself Abgenix in 1999)." The evidence contradicts this. Abgenix, Inc. was a Cell Genesys subsidiary (spun out 1996), and GenPharm sued Abgenix/Cell Genesys for infringement in 1996–97; the two settled via a Settlement and Cross-License Agreement dated 1997-03-26 among GenPharm, Cell Genesys, Abgenix, Xenotech L.P. and Japan Tobacco. Abgenix's own lineage patents descend from Cell Genesys ("Generation of xenogeneic antibodies," 1991), and Abgenix became Amgen Fremont Inc. after Amgen's 2006 acquisition — a different ownership tree from this patent's. The GenPharm line runs GenPharm → Medarex → Bristol-Myers Squibb. The earlier Litigation and PTAB sections' statement that ownership "moved through the Medarex → Bristol-Myers Squibb lineage" is the accurate one; the Abgenix-as-successor statement is not, and should be treated as superseded.

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Assignment timeline

One recorded assignment. That is the entire chain of title of record.

• 1993-01-28 (executed) / recorded 1993-02-16 — Reel 006409/0573
  • Conveyance: Assignment of assignors' interest (USPTO brief: "ASSIGNMENT OF ASSIGNORS INTEREST.; ASSIGNORS: LONBERG, NILS; KAY, ROBERT M.")
  • Assignor: Nils Lonberg; Robert M. Kay (individually, both inventors)
  • Assignee: GenPharm International, Inc., a California corporation
  • Correspondent: Not recovered. The notice-of-recordation metadata that would carry the filing attorney/firm was not returned by any source I could reach. I decline to guess; the reel/frame, dates and parties above are the verified elements.
  • Context: Founder/employee-to-company assignment; routine prosecution-stage perfection of title. No third party involved.
  • Corroboration: This is the only reassignment event in the Google Patents legal-events block of the authoritative record supplied in the prompt ("1993-02-16 — Assigned to GENPHARM INTERNATIONAL, INC. — reassignment … Assignors: KAY, ROBERT M., LONBERG, NILS"), and the only reel/frame the structured record exposes (REEL/FRAME 006409/0573, effective date 1993-01-28).

No post-issuance assignment is on record that I could retrieve. Specifically, I found no recorded instrument transferring title out of GenPharm International, Inc. — not for the 1997-10-21 Medarex merger, and not for the Bristol-Myers Squibb acquisition of Medarex. Hypothesis (labeled as such, not a finding): because GenPharm survived the 1997 transaction as a continuing wholly owned subsidiary of Medarex rather than being merged out of existence, the patent's record title may have remained in "GenPharm International, Inc." indefinitely, while beneficial ownership passed up the chain by stock acquisition. That would explain both the absence of a recorded instrument and why Google Patents still renders the assignee string as "Genpharm International Inc." This is a plausible reading of a negative — it is not documentary proof, and the correct check is a title search of Reel 006409 and of GenPharm's later reel ranges at the Assignment Center.

Note: I checked but did not find whether BMS recorded a bulk merger assignment covering the GenPharm portfolio. Bulk merger recordations (the pattern seen in the Reel 033xxx series for other parties) are the likely location if one exists. Unverified.

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Timeline diagram

timeline
    title Ownership chain US 5545806
    1989 : GenPharm International founded
    1990 : Priority date Aug 29
    1993 : Inventors assign to GenPharm
         : Reel 006409 frame 0573
    1996 : Patent issues Aug 13
    1997 : Medarex acquires GenPharm Oct 21
    2009 : Bristol-Myers Squibb acquires Medarex
    2013 : Patent expires Aug 13

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NPE / troll-pattern signals

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Verdict

Insufficient data — with the direction of the evidence running clearly non-NPE.

Justification (2–3 sentences). The assignment record I could actually retrieve contains exactly one instrument: inventors Lonberg and Kay to GenPharm International, Inc., Reel 006409/0573, executed 1993-01-28 and recorded 1993-02-16 — and the authoritative legal-events block supplied in the prompt corroborates that this is the only reassignment of record. Because the subsequent ownership changes (Medarex's 1997-10-21 acquisition of GenPharm; Bristol-Myers Squibb's later acquisition of Medarex) are documented in SEC filings and corporate disclosure rather than in any reel/frame I could verify, the strict verdict is insufficient data — "only the original assignment" is precisely this case. Every affirmative NPE signal is nonetheless absent: no shell LLC, no known asserter, no cascading transfers, no bankruptcy sale, no defensive aggregator, and the single recorded transfer is a routine employee assignment from three years before issuance.

Verify at: https://assignmentcenter.uspto.gov/ (search the patent number, or run a title search across Reel 006409 and the GenPharm reel ranges) and https://patents.google.com/patent/[US5545806A](/patent/US5545806A)/en (Legal Events + "PTAB proceedings" tabs).

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Two open items I would close before relying on this

1. Confirm whether a Reel 036xxx-era merger recordation exists covering the GenPharm portfolio (Medarex 1997 / BMS 2009). If one does, the chart gains a link and the verdict strengthens to operating-company on the record itself, not merely on SEC corroboration. If none exists, the "record title stayed in GenPharm International, Inc." hypothesis is the better reading.
2. Recover the correspondent of record for Reel 006409/0573, chiefly to rule signal #3 in or out — and, if a Medarex/BMS bulk recording is found, to check whether a single corporate-law or IP-department correspondent appears across many GenPharm-family patents. That is a useful portfolio-provenance tell even where no NPE is involved. The FibroGen-disclosed pattern of Medarex/BMS-era filings used in-house legal contacts (e.g., a named legal-department attorney rather than an outside firm), so I would expect correspondent strings of that type on any bulk recording.

I'll search for the USPTO record and the cited prior art for US 5,545,806.

Let me pull the actual front-page citation list from patent full-text sources.

Let me get the front-page references from the full-text patent sources.

Prior-Art Analysis — US Patent 5,545,806

Scope flag before anything else. You asked me to look at each patent citation on US 5,545,806 and map it to § 102. I was not able to retrieve the examiner-cited front-page "References Cited" list for this patent within my tool budget. My searches kept returning forward citations (later patents — TW202102544A, CN111670203A, RU2743590C2, EP3693013, DK2797957T3, etc. — that cite '806 as background), not '806's own face. I therefore split this memo into references I can ground, and a clearly labeled unverified block. I have not invented any citation.

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1. What I could and could not verify

To get the examiner-cited list definitively, pull the face page at https://patents.google.com/patent/US5545806A/en (Citations tab), https://ppubs.uspto.gov, or the file wrapper at https://patentcenter.uspto.gov (application 07/990,860).

Literal-record notes: as printed in the '806 text, the reference is spelled "Buchini" (not Bucchini), the rabbit referenced gene is written "rabbit K gene", the author is printed "Bruggemann", and the Sado citation is printed "154:264271" without an internal hyphen. I reproduce these verbatim and do not auto-correct them.

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2. Group A — Prior art grounded in the '806 specification itself (verified)

These are the references the applicants themselves distinguished or relied on. Under § 102 they are the only printed publications I can cite with confidence. § 102 bracket assumes the pre-AIA statute (priority 1990-08-29; filed 1992-12-16), which is correct for this patent.

Critical-date math used below: earliest priority = 1990-08-29; actual filing = 1992-12-16; one-year § 102(b) bar relative to the earliest priority = 1989-08-29. Because '806 is a CIP chain, claims entitled to the 1990-08-29 parent get the 1989-08-29 bar; claims supported only by later-filed matter get the 1991-12-16 bar.

A.1 — Unrearranged immunoglobulin transgenes in mice (the § 102-relevant core)

A.2 — Immunoglobulin locus structure, switch regions, and sterile transcripts

A.3 — Isotype-switch biology and B-cell development

A.4 — Antisense suppression (relevant only to the suppression-dependent claims)

A.5 — Reference works

• Kabat et al., Sequences of Proteins of Immunological Interest (1991), U.S. Dept. of Health and Human Services — CDR/framework definitions (cited for the CDR1/CDR2/CDR3 and FR1–FR4 definitions underlying FIG. 1 and the somatic-mutation discussion). Not anticipatory of any claim.

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3. Group B — The patent's own co-pending applications (NOT prior art)

The specification relies on these, and they are the applicants' own work, not "by others" under pre-AIA § 102(a)/(b)/(e). They cannot be § 102 art against '806:

• U.S.S.N. 07/574,748, filed 1990-08-29 — "Transgenic Non-Human Animals Capable of Producing Heterologous Antibodies" (the parent).
• U.S.S.N. 07/574,747, filed 1990-08-29 — "Intracellular Generation of DNA by Homologous Recombination of DNA Fragments."
• PCT/US91/06185, filed 1991-08-28 — published as WO 92/03918 on 1992-03-19, naming Lonberg and Kay. Published only ~9 months before the 1992-12-16 filing, and it is the inventors' own disclosure → not § 102(b), and not § 102(a) "by others."
• U.S.S.N. 07/810,279, filed 1991-12-17; U.S.S.N. 07/853,408, filed 1992-03-18 (priority parents claimed on the Google Patents record).

This is an affirmative defensive point, not just a footnote: the closest-in-subject-matter documents to '806 are the applicants' own earlier filings, which removes the family from § 102(a)/(e) exposure.

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4. Group C — U.S. patent references on the '806 face — UNVERIFIED

I was not able to open the face page in this session, so I am not going to print a list of US patent numbers or their dates. Doing so would be fabrication. What I can say with confidence about the category of art the examiner would have cited on a 1992-filed transgenic-animal case:

• Foundational transgenic-mouse/gene-transfer patents (e.g., the Leder/Stewart and Wagner-era patents) — these teach making a transgenic mammal, nothing about human Ig miniloci, D segments, or isotype switching. On the § 102 axis they reach no claim in this patent; they are at most § 103 backdrop.
• Patent documents directed to human immunoglobulin locus fragments or to gene targeting in ES cells — relevant to the knockout/suppression-dependent claims only.

Verify the actual list at the three URLs in § 1. The number that matters most — the Leder-family and Krimpenfort-family transgenic patents — I will not assert without the face page.

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5. § 102 claim map — bottom line

Caveat: I only have verified text for claim 1 and fragments of claims 13–14 (per the summary section). A complete claim-by-claim § 102 chart requires the full claim set from PatentCenter. What follows is a limitation-by-limitation read of claim 1, which is the broadest and the only independent claim I can see.

Claim 1 requires, in combination:

1. Contacting a transgenic mouse with a pre-selected antigen;
2. The mouse genome contains germline copies of a transgene with human VH, human D, and human JH segments;
3. The transgene undergoes isotype switching in vivo from transgene-encoded mu to a downstream human gamma isotype;
4. A minilocus limitation: the number of nucleotides between the transgene's mu and gamma segments is less than the corresponding human-germline distance; and
5. Collecting heterologous human gamma immunoglobulins that bind the antigen.

Net conclusion: On the references I can verify, no single reference anticipates claim 1, and the combination limitation in element 4 (a compacter-than-germline Cμ→Cγ spacing that still supports real in-vivo switching) is the limiting feature that separates '806 from the Art. The strongest § 102 theory anyone could mount is Bruggemann 1989, and it is a § 102(a) theory only (it is not § 102(b) as to 1990-08-29-entitled claims because October 1989 post-dates the 1989-08-29 bar). Everything else in this memo is § 103 material, not § 102.

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6. Contradictions with the previously generated sections — flagged

1. Litigation posture. The Litigation summary called "GenPharm International v. Abgenix" an internally incoherent caption and suggested the Nature Biotechnology table entry was likely a data artifact or corporate-succession coding. The PTAB challenges section then characterized the mid-1990s suit as GenPharm asserting '806 and '5,825 against Abgenix, Inc., a Cell Genesys subsidiary — which is coherent (Abgenix was spun out of Cell Genesys), not incoherent. These two sections are in tension and one is wrong. The reconciliation is that Cell Genesys/Abgenix as defendant and GenPharm as plaintiff is a normal caption; the "implausibility" observation in the litigation section should be withdrawn pending the docket. I have no verified case number either way.
2. Dates. The prior sections are stamped 2026-09-28; this task header says April 26, 2026. The analysis is unaffected, but note the discrepancy if these are being merged into one document.
3. Claim count. The summary says "claims 1–14, all untested at the PTAB, none canceled," but also says the full claim set was never verified and that claim 13 recites a NotI/pHC1 insert while claim 14 recites collecting serum with human γ1 chains. My § 102 chart is therefore limited to claim 1 plus those two fragments. Do not treat the "14 claims" figure as verified.

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7. What must be done to close the gaps

1. Pull the face page of US 5,545,806 (Citations tab at https://patents.google.com/patent/US5545806A/en, or https://ppubs.uspto.gov) to get the verified US-patent and foreign-patent reference list; then re-run § 102 on those.
2. Pull the full 14-claim set from https://patentcenter.uspto.gov (application 07/990,860) and the prosecution history for the amendment that added the "less than the number of nucleotides… in the human germline" language — under pre-AIA § 102/§ 103, the examiner's basis for allowing that limitation is the best predictor of what art was considered closest.
3. Obtain and read Bruggemann et al., PNAS 86:6709-6713 (1989) in full, specifically the transgene map (does it include human Cγ?) and whether any switched human IgG was detected. That single document determines whether claim 1 has a viable § 102 attack at all.
4. Obtain WO 92/03918 and the '806 parent 07/574,748 as filed, to confirm which claims are entitled to the 1990-08-29 priority and therefore which critical date (1989-08-29 vs. 1991-12-16) governs each § 102(b) analysis.

I'll ground the prior-art record before writing the analysis. Let me pull the cited references and their content.

Let me pull the specific prior-art references cited on the face of this patent.

Now let me verify the content of the key pre-priority-date references.

Obviousness Analysis — US 5,545,806 under 35 U.S.C. § 103

Analyst note on inputs. You asked me to work from "the Prior Art section of this page." The Google Patents rendering I retrieved supplies only the prior-art keyword block (human; transgene; gene; sequences; segments) and the abstract-derived concept list — not a machine-readable "References Cited" table. The actual citation list is reproduced on the issued patent's front page, which the search returned as a PDF text extract of patentimages.storage.googleapis.com/.../US5545806.pdf, and in near-identical form on sibling US 5,625,126 (same family, same inventorship, essentially the same art). I used those two lists as the prior-art record and have said so where it matters. I did not verify each reference's full text; where I am relying on training knowledge rather than a retrieved source, I say so explicitly.

Two flags before the analysis:

1. Contradiction between the two previously generated sections. The Litigation section states that Abgenix "is the entity that succeeded to GenPharm's business (GenPharm renamed itself Abgenix in 1999)," while the PTAB challenges section calls Abgenix "a Cell Genesys subsidiary." These are different corporate histories and cannot both be right. I cannot resolve it from the retrieved record, and it does not affect § 103 analysis (ownership is irrelevant to validity), so I set it aside — but you should not carry both statements forward.
2. Date discrepancy. The current task header says April 26, 2026; the system date and the prior sections use 2026-09-28. Immaterial to § 103; noted for the record.

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1. The threshold question that governs everything: the effective filing date

Claim 1 of the '806 patent is a CIP claim. US 07/990,860 was filed 1992-12-16, claiming benefit back through US 07/853,408 (1992-03-18) and US 07/810,279 (1991-12-17), with the family root at US 07/574,748 (1990-08-29) — the date Google Patents reports as the "prior art date." The prior-art set is not the same under each date, so any § 103 opinion must state which date it assumes:

My working assumption below is the 1990-08-29 date for the priority-date-sensitive art, because that is the most applicant-favorable assumption and therefore the correct one for a validity opinion. Under that assumption WO 91/00906 and WO 91/10741 drop out as § 102 art (they published 1991-01-24 and 1991-07-xx, after the priority date) — but note that the applicant's own specification relies on WO 90/04036 and EP 0315062, both of which predate 1990-08-29.

References on the front page that cannot be prior art at all and should be excluded from any § 103 chart: Jung et al., Science 259:984 (1993); Fishwild et al., Nat. Biotechnol. 14:845 (1996); Shimizu et al., J. Exp. Med. 173:1385 (1991); Rath et al., J. Immunol. 146:2841 (1991); Kitamura et al., Nature 350:423 (1991); Soriano et al., Cell 64:693 (1991); Lo et al., Eur. J. Immunol. 21:1001 (1991); Mills et al., NAR 18:7305 (1991); Brüggemann et al., Eur. J. Immunol. 21:1323 (1991). These are listed on the face of the patent but post-date the priority chain — an artifact of later prosecution and family citations. Their presence is not an admission of prior-art status.

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2. The person of ordinary skill in the art (POSA)

As of August 1990: a Ph.D.-level immunologist/molecular biologist with 2–5 years' experience in transgenic mouse production and immunoglobulin gene cloning, working as part of a team including a molecular biologist and a hybridoma technologist. This POSA knows: (a) microinjection size limits (practical ceiling roughly 100–200 kb, with YAC-based transgenesis an emerging but unreliable alternative — Murray & Szostak 1983); (b) the deletional model of heavy-chain class switching (Ravetch 1980; Nikaido 1981/1982); (c) the requirement of surface IgM for B-cell maturation and the therapeutic inadequacy of IgM (Kohler & Milstein 1975; the background discussion in WO 91/00906); (d) 1987–1989 reports of unrearranged heterologous Ig transgenes rearranging in mice (Bucchini; Goodhardt; Brüggemann).

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3. The core reference: Brüggemann et al., PNAS 86:6709–6713 (1989)

This is the single most damaging reference and the linchpin of any § 103 case. Verified abstract language:

"mice were created that carry a human heavy-chain minilocus comprising unrearranged immunoglobulin variable, diversity, and joining elements linked to a human mu-chain gene. The gene segments of this minilocus are rearranged in a large proportion of cells in thymus and spleen but not in nonlymphoid tissue. Some 4% of the B lymphocytes synthesize human mu chains resulting in a serum titer of about 50 micrograms of transgenic IgM antibody per ml. Hybridomas were established from the transgenic mice that stably secreted several micrograms of antibodies containing human mu heavy chains per milliliter."
— https://pubmed.ncbi.nlm.nih.gov/[2505258](/patent/2505258)/ ; https://www.pnas.org/doi/abs/10.1073/pnas.86.17.6709

That reference alone discloses elements (a), (b) and (e) of claim 1 and most of the conceptual apparatus — a functional human V-D-J-Cμ minilocus transmitted through the germline of a mouse, rearranging in B-lineage cells, producing human μ in serum, and recoverable as a monoclonal via fusion. What it does not disclose is a transgene-encoded γ constant region, isotype switching to γ in vivo, or the "shorter than germline" distance between μ and γ. Those three gaps define the entire § 103 question.

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4. Mapping the remaining limitations

Caveat on Durdik/Gerstein. I was unable to re-verify the Durdik and Gerstein abstracts in this session (tool limit reached). My statement of their holdings rests on the titles as they appear on the patent's own front-page reference list ("Isotype switching by a microinjected .mu. immunoglobulin heavy chain gene in transgenic mice, Proc. Natl. Acad. Sci. USA 86:2346-2350 (1989)" and "Isotype switching of an immunoglobulin heavy chain transgene occurs by DNA recombination between different chromosomes, Cell 63:537-548 (1990)") plus my recollection of their content. The titles alone carry substantial weight — they are the applicant's own cited art and they state the operative teaching in the title. But before filing anything, pull the full texts and confirm the constructs used.

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5. The § 103 combinations

Combination A (primary) — Brüggemann 1989 + Durdik 1989 + WO 90/04036, with Rabbitts 1981 / Berman 1988 / Sato 1988 for the map

What it renders obvious. Brüggemann 1989 supplies the transgenic mouse with a germline human V-D-J-Cμ minilocus that rearranges and expresses human μ (elements a, b, and the μ half of c). Durdik 1989 supplies the teaching that a heavy-chain transgene in a mouse can undergo isotype switching in vivo — eliminating the only doctrinal gap on element (c). Rabbitts 1981 ("Human immunoglobulin heavy chain genes: evolutionary comparisons of C.mu., C.delta. and C.gamma. genes and associated switch sequences"), Berman 1988 (the 670–830 kb NotI fragment containing all six VH families, D, J, and the μ, δ, γ3, γ1, α1 constant regions), Sato 1988 (the 23 kb SfiI/SpeI fragment spanning J through Cμ with 3′ cis regulatory elements) and Nikaido 1981/1982 (Sμ/Sγ structure) supply the sequence information and the germline spacing measurement needed to construct the γ-bearing variant and to know that it is shorter than germline.

Motivation to combine — articulated as a challenger would:

1. Therapeutic inadequacy of IgM is expressly stated in the art. Durdik's co-field and the contemporaneous patent literature state it plainly: "such cells predominantly produce antibodies of only the IgM isotype, which is not appropriate for many clinical uses" (WO 91/00906, background). The '806 specification itself repeats this framing ("isotypes other than IgM are desired for therapeutic uses"). A POSA seeking serum IgG, IgA or IgE effector function (Fc receptor binding, complement activation) had a direct, stated reason to add a downstream human γ gene.
2. The switch mechanism is deletional, so the intervening DNA is dispensable. Ravetch 1980 and Nikaido 1981/1982 taught that class switching deletes the intervening CH exons. A POSA therefore knew that the sequences between Cμ and Cγ are removed anyway during the very event the transgene must support. Removing them at the cloning stage is not a functional change to the switch mechanism; it is the same deletion, executed earlier. This is the strongest answer to the "less than germline" limitation.
3. The size constraint is a known problem with a finite set of known solutions. Microinjection imposes a practical ceiling; Murray & Szostak 1983 offered YACs, but YAC transgenesis in 1990 was technically unreliable. Deleting intervening sequence to fit a microinjectable fragment is the ordinary engineering response — and Brüggemann 1989 had already demonstrated that a ligated minilocus (necessarily non-germline in spacing) works in a mouse. Once Brüggemann's minilocus is the starting design, the "shorter than germline" limitation is close to inherent in the approach.
4. KSR-style predictable variation. Under KSR Int'l v. Teleflex, 550 U.S. 398 (2007), arranging known gene segments in a known vector to solve a known size problem, where the art teaches that switch sequences function independently of the constant region they are placed next to, is "a predictable variation" using "a known technique to improve similar devices in the same way."

Combination B — Brüggemann 1989 + WO 91/00906 (only if the 1992 filing date controls)

WO 91/00906 (Genetics Institute; Wood & Kaufman; PCT/US90/03894; published 1991-01-24) is, on its face, very close art. From the retrieved PDF text:

"If the structure is attached in this manner to the gamma constant region in a construct similar to that of Example 2 with μ and gamma constant regions, selection for expression of DHFR by conventional means would allow selection of cells that have class switched from transgene μ to gamma expression." — https://patentimages.storage.googleapis.com/c2/50/29/84d512883f7a20/WO1991000906A1.pdf

That is an express teaching of (i) an unrearranged human Ig transgene carrying both μ and γ constant regions and (ii) the expectation that the transgene class-switches from μ to γ. Combined with its claim 1 (germline-integrated unrearranged human Ig segments in a non-human eukaryotic animal, capable of rearranging and producing antibodies with rearranged exogenous heavy chains) and its immunization/hybridoma disclosure, Combination B leaves only the "shorter than germline" spacing limitation to be supplied by the engineering rationale in point 2 above. This combination is materially stronger than Combination A — which is why the effective filing date is the decisive battleground. If a defendant can show claim 1 is not entitled to the 1990 root disclosure (e.g., because the "minilocus" spacing limitation first appears in the 1992 CIP), WO 91/00906 becomes live art and the case tightens considerably.

Combination C — add WO 91/10741 (Cell Genesys, "Generation of Xenogeneic Antibodies")

WO 91/10741 appears on the '806 front page and is the Jakobovits/Cell Genesys counterpart. Same date problem: published July 1991. Relevant only under the later-date scenario; I did not retrieve its text this session and will not characterize its disclosure beyond noting its presence on the face of the patent and its title.

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6. Where the challenger will lose ground (and the patent owner will defend)

I would not write an opinion that claim 1 is clearly obvious. Three real weaknesses in the § 103 case:

1. No reference demonstrates transgene-encoded γ expression from a compacted human locus. Brüggemann 1989 got 4% of B cells / ~50 µg/ml of human μ and no IgG. Durdik and Gerstein showed switching in transgenes, but (on my recollection of Gerstein at least) via trans-chromosomal recombination with the endogenous locus — i.e., non-classical mechanisms that do not establish that a self-contained human μ→γ minilocus will switch. The applicant's own specification seizes on exactly this: "there have been no reports of heterologous transgenes that undergo successful isotype switching." That is a strong objective-evidence datum against obviousness, because it is the applicant's contemporaneous statement that the field had not achieved the result.
2. The art's preferred solution ran the other way. Berman 1988 and the '806 specification both identify the 670–830 kb NotI fragment (full germline configuration) as the preferred transgene, and Murray & Szostak 1983 pointed the field to YACs for large, germline-spaced loci. A defendant arguing that telescoping the μ–γ interval was obvious must explain away a body of art whose accepted answer to "we need bigger loci" was make them bigger, not shrink them. That is a colorable teaching-away argument under In re Gurley.
3. Unpredictability of switch frequency and order. The '806 specification itself states that "the mouse switch sequences are optimized to function with the mouse switch recombinase enzyme system, whereas the human switch sequences are not," and contemplates grafting switch regions and linking switch regions to CH genes they do not naturally neighbor in order to modulate switching frequency. A challenger should expect the patent owner to argue that whether a compressed human μ/γ interval switches at a useful frequency in vivo was not predictable from the deletion model alone.

Secondary considerations the patent owner would marshal: long-felt need (failure of mouse/human hybridomas, EBV-transformed human B cells and human/human hybridomas — recited at length in WO 91/00906's background and in the '806 specification); industry adoption and licensing of the resulting platform; and the commercial success of the human-antibody transgenic mouse lines that trace to this family. Note the asymmetry: these are post-1990 facts, so they support non-obviousness but do not defeat a § 102 anticipation, and their nexus to the specific "shorter than germline" limitation (rather than to human-Ig transgenic mice generally) is the nexus question a court would press.

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7. Dependent claims 3–14

The previously generated summary records that claims 3–13 add structural/transgene limitations (the pHC1 NotI insert; VH251 and VH105; the DIR2 D segment; a 5.3 kb HindIII γ1 switch fragment) and that claims 13–14 recite expression of human μ and γ1 chains and collection of serum. I could not verify the full claim set and I flag that expressly — the claim count, the existence of any additional independent claim, and the exact wording of claims 2–12 are not confirmed from the retrieved record.

Two observations that hold regardless:

• There is no composition-of-matter or animal claim in this patent — the set appears to be method-only. That matters for the prior-art analysis because the structural elements (pHC1 insert, VH251, DIR2) enter the case only as method step limitations, and the challenger need not anticipate the construct itself, only show that performing the recited method with those elements would have been obvious.
• The narrower structural claims are harder to invalidate. VH251 and DIR2 are published human germline sequences (Berman 1988; Ichihara 1988; Siebenlist 1981), so a combination can reach them — but a claim reciting a specific NotI insert plus specific V and D segments plus a specific 5.3 kb HindIII switch fragment requires the challenger to show the POSA would have selected that combination, which is a materially higher burden than for claim 1.

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8. Bottom line

The decisive question is not "what does Brüggemann teach" but "what is claim 1's effective filing date." Everything else follows from it.

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9. Verification steps before reliance

1. Pull the full claim set from USPTO Patent Center / the granted patent PDF for 07/990,860 — confirm claim count, confirm method-only status, confirm the exact wording of claims 2–12, and confirm my transcription of claim 1's "less than…human germline" clause.
2. Retrieve and read WO 90/04036 in full (I could not; search budget exhausted). It predates 1990-08-29 and is the applicant's own cited art; if it discloses a μ-plus-γ human transgene, the § 103 case strengthens materially even under the early date.
3. Retrieve Durdik 1989 (PNAS 86:2346) and Gerstein 1990 (Cell 63:537) in full. Confirm which constant regions their transgenes carried and whether switching was classical (intra-transgene Sμ/Sγ) or trans-chromosomal. This determines whether element (c) is truly met.
4. Determine, from the prosecution file wrapper, whether the "shorter than germline" limitation was added by amendment and on what record. That both fixes the effective-date question and reveals the examiner's own § 103 reasoning — the cheapest way to see the strongest ground the applicant was forced to overcome.
5. Confirm the priority-chain dates independently (the Google Patents "priority claimed from" entries are automated inferences, not legal conclusions).
6. Check Brüggemann et al., Eur. J. Immunol. 21:1323 (1991) — "expression from 100 kb of the human IgH locus." If that construct preserved germline μ–γ spacing, it is a teaching-away citation for the patent owner; if it was compacted, it is a teaching-toward citation for the challenger. Either way it is not prior art at the 1990 date.

Primary sources used: Brüggemann 1989 abstract — https://pubmed.ncbi.nlm.nih.gov/2505258/ and https://www.pnas.org/doi/abs/10.1073/pnas.86.17.6709 ; WO 91/00906 full text — https://patentimages.storage.googleapis.com/c2/50/29/84d512883f7a20/WO1991000906A1.pdf ; '806 front-page reference list — https://patentimages.storage.googleapis.com/56/3a/f1/4792f30f8783f6/US5545806.pdf ; sibling reference list — http://www.everypatent.com/comp/pat5625126.html ; EP 0315062 — https://patents.google.com/patent/EP0315062A3 ; patent record — https://patents.google.com/patent/US5545806/en .