US 5891636

I'll search for authoritative information on US 5891636, including any litigation or Federal Circuit activity.

The general litigation search returned unrelated "589" patents, so let me run targeted searches for this specific patent number and any case involving it.

Let me check for interference proceedings and any appellate review specific to this patent.

Summary — US Patent 5,891,636

Important scope note up front: I searched for this exact number. There is no 2026 CAFC docket activity for US 5,891,636 that I can verify. One search hit referenced a Federal Circuit case about "the '589 patent" (UCB Inc. v. Actavis Laboratories UT Inc., Fed. Cir. Apr. 12, 2023 — rotigotine transdermal patches, D. Del. No. 1:19-cv-00474-KAJ). That is a different patent (a 9,xxx,xxx-series rotigotine patent), not US 5,891,636, and I am excluding it. The '636 patent's likely litigation/enforcement window closed around 2009, which is consistent with no 2026 appellate presence.

Bibliographic data (from the patent document and patent databases)

Continuity: The patent states it is a continuation of Ser. No. 08/636,748 (filed Apr. 19, 1996, now US 5,716,785), which is a continuation of Ser. No. 07/957,647 (filed Oct. 5, 1992, now US 5,554,552), which is a continuation of Ser. No. 07/411,370 (filed Sep. 23, 1989, now abandoned).

⚠️ Identifier/date discrepancy I am flagging rather than correcting: Google Patents lists a "priority date" of 1989-09-22; Unified Patents lists 1989-09-21; the patent's own text (authoritative per instructions) recites the earliest application, Ser. No. 07/411,370, as filed Sep. 23, 1989. I report all three as found rather than harmonizing them.

Abstract (verbatim)

"This invention relates to the use of promoters for ribonucleic acid amplification and other genetic manipulations. Processes are provided wherein complementary deoxyribonucleic acid (cDNA) is synthesized from a ribonucleic acid (RNA) sequence using a complementary primer linked to an RNA polymerase promoter region complement and then anti-sense RNA (aRNA) is transcribed from the cDNA by introducing an RNA polymerase capable of binding to the promoter region. Additional processes using the resulting aRNA are also described."

Plain-language overview of the independent claims

The patent claims are procedural (product-by-process style) and each requires the same core three-step engine: (1) hybridize a primer complex (target-complementary primer + RNA polymerase promoter in antisense orientation) to a population of mRNAs; (2) make double-stranded cDNA, where the second strand is made without an exogenous primer and so carries the promoter in sense orientation; (3) linearly transcribe many anti-sense RNA (aRNA) copies off that promoter.

• Claim 1 — Gene expression library. A library of two or more messages whose relative abundance reflects the sample's physiologic state, "thereby permitting diagnosis of a disease or condition," made by the above steps plus (d) quantitating the aRNAs so the collection represents an "expression spectrum" of the cell/tissue.
• Claim 5 — Expression library. Essentially the same process, yielding an "expression library" of the cell or cell population (no diagnostic limitation).
• Claim 15 — Thalassemia detection method. Same amplification process on mammalian-cell mRNAs, with quantitation generating an expression spectrum that permits identification of abnormal hemoglobin gene expression, thereby permitting determination of a thalassemia disease.
• Claim 24 — Kit. A kit with multiple primer-complex species and instructions, where the primers are complementary to a plurality of hemoglobin genes and carry an antisense-orientation promoter — i.e., a thalassemia-detection kit.
• Claim 26 — Detecting mutant hemoglobin genes. Same process; quantitation indicates expression of mutant hemoglobin genes relative to a normal mammalian cell.
• Claim 27 — Identifying a pathogen-specific sequence. Same process applied to a population of pathogen-specific nucleic acid sequences (DNA or RNA); presence of aRNA indicates the pathogen sequence in the cell/tissue.
• Claim 37 — Identifying a member of a gene family. Same process, with primer complementary to mRNAs of the gene family. (Note: the claim text in my source is truncated mid-claim-37; I do not have its full final step.)
• Claim 43 — Identifying alternatively spliced transcripts. Same process, primer complementary to the gene; the resulting aRNAs are used to identify splice variants.
• Claim 49 — Identifying genetic polymorphisms. Same process, followed by (d) determining the sequence of the aRNAs to call polymorphisms.

Representative dependent claims add: bacteriophage promoters, specifically T3, T7, or SP6 (e.g., claims 10, 11, 19, 20, 32, 33, 38, 39, 44, 45, 50, 51); Northern/Southern blot hybridization readouts; labeled detection; poly(dT) primers; tissue sources; and comparison to a normal expression spectrum (claim 18).

Litigation and licensing (verified, but note the dates)

• Incyte Genomics v. Affymetrix (N.D. Cal., filed Aug. 2000) asserted US 5,716,785 and 5,891,636 — described as non-PCR linear RNA amplification IP. Incyte held an exclusive license from Layton Bioscience. Settled Dec. 21, 2001, with cross/royalty-bearing licenses. Incyte 8-K
• Incyte v. Gene Logic (N.D. Cal., filed Aug. 2000) asserted 5,716,785, 5,891,636, and 6,023,659; settled with a non-exclusive license and dismissal.
• A separate BPAI (Board of Patent Appeals and Interferences) proceeding involving Stanford-licensed applications was expressly excluded from the Affymetrix settlement, with Incyte seeking de novo review in N.D. Cal. — I could not confirm the outcome.
• Licenses to the '785/'636 pair were granted to Merck, Chiron, and Linden Bioscience (via Incyte).
• Google Patents records "Family has litigation" linking to Darts-ip (family ID 23628663).

Uncertainty disclosures

1. No verified 2026 CAFC docket touches this patent; searches returned only unrelated "589"-numbered patents, which I excluded.
2. A PTAB IPR is highly unlikely because the patent expired in 2009, but I did not exhaustively verify the absence of one.
3. The earliest priority date is reported inconsistently across databases (Sep. 21 vs. Sep. 22 vs. Sep. 23, 1989); the patent's own continuity statement says Sep. 23, 1989.
4. Full text of claim 37 and the exact independent-claim set beyond claim 37 are not complete in my source; claims 44–54 appear dependent on 37/43/49. I would verify against the USPTO PatentCenter/PatFT record before relying on the precise claim numbering.
5. Attorney/agent of record conflicts between sources (Kitchell vs. Arnold, White & Durkee) — unresolved.

Sources: Google Patents US5891636; Justia Patents; FreePatentsOnline; Incyte 8-K; BioProcess Online.

I'll research litigation involving US patent 5891636 across patent litigation databases.

Good results. Let me dig deeper into specific cases and parties.

Let me search the Stanford NPE litigation database and look for any other cases.

Litigation Involving U.S. Patent No. 5,891,636

Patent identification (verified from Google Patents): US 5,891,636 — "Processes for genetic manipulations using promoters." Original assignee: Leland Stanford Junior University (Board of Trustees). Inventors: Russell N. Van Gelder, Mark E. Von Zastrow, Jack D. Barchas, James H. Eberwine. Priority date 1989‑09‑22; granted 1999‑04‑06; expired (anticipated) 2009‑09‑23. The Google Patents record itself carries a "Family has litigation" flag (Darts‑IP family 23628663), and the patent is one of a family that includes US 5,545,522, US 5,716,785, and US 6,291,170.

Note on scope: Identifiers are reported literally as found. Two cases below specifically assert the '636 patent; additional related cases in the same litigation package involved sibling patents only and are listed separately to avoid conflating them.

Cases in which U.S. 5,891,636 was actually asserted

1. Incyte Genomics, Inc. v. Gene Logic, Inc.

Sources: Stanford NPE Litigation Database (Incyte Genomics, Inc. v. Gene Logic, Inc., 3:00-cv-04627, N.D. Cal.); BioCentury ("Incyte files suits against Affymetrix and Gene Logic," Aug. 18, 2000); The Free Library / BioCentury report on the January 2001 settlement (non‑exclusive license to Gene Logic).

2. Incyte Genomics, Inc. v. Affymetrix, Inc.

Sources: Incyte Genomics, Inc. SEC filing (Dec. 21, 2001); Affymetrix/Incyte 10‑K and 10‑Q notes ("Note 12 – Litigation"); Incyte investor release "Affymetrix and Incyte Genomics Settle All Patent Infringement Litigation" (Dec. 21, 2001); BioCentury (Aug. 18, 2000).

Related cases in the same settlement package (did NOT assert 5,891,636)

These are commonly found alongside the '636 litigation and were part of the same December 21, 2001 global settlement, but their asserted patents were different (Affymetrix's microarray patents, or Stanford's RNA‑amplification applications):

• Affymetrix, Inc. v. Synteni, Inc. and Incyte Pharmaceuticals, Inc., Case Nos. C 99‑21164 JF and C 99‑21165 JF (N.D. Cal.). Filed by Affymetrix in January and September 1998. Asserted Affymetrix patents U.S. 5,445,934; 5,744,305; 5,800,992. Settled/dismissed Dec. 21, 2001. Not a '636 case.
• Incyte Pharmaceuticals, Inc. (and Board of Trustees of Leland Stanford Junior University) v. Affymetrix, Inc., Case No. C 99‑21111 JF (N.D. Cal.) — a 35 U.S.C. § 146 action seeking review of Board of Patent Appeals and Interferences decisions in Stanford‑licensed applications (see Incyte Pharmaceuticals, Inc. v. Affymetrix, Inc., 131 F. Supp. 2d 1154 (N.D. Cal. 2000), denying Affymetrix's motion to dismiss). This case involved Stanford‑owned applications relating to the same technology family — but the report explicitly states C 99‑21111 "is not being settled or dismissed" as part of the Dec. 21, 2001 stipulation and did not assert the '636 patent.
• Incyte's opposition to Affymetrix European Patent No. EP 0 619 321 — a European Patent Office proceeding, not U.S. litigation.

Summary and confidence

• Two (2) U.S. district court cases specifically asserted U.S. 5,891,636: Incyte v. Gene Logic and Incyte v. Affymetrix, both in N.D. Cal., both filed in 2000 and both resolved by settlement (Jan. 2001 and Dec. 21, 2001 respectively). There was no judgment on validity or infringement of the '636 patent — both ended in licenses/dismissals with prejudice.
• In both cases the patent was enforced by Incyte Genomics, Inc. as exclusive licensee (licensed from Layton Bioscience, Inc.), while the patent remained owned by Leland Stanford Junior University.
• I found no IPR, PGR, or CAFC appeal specifically addressing U.S. 5,891,636, and no litigation after 2001. The patent expired Sept. 23, 2009, which forecloses prospective infringement claims on the expired claims.
• Caveats / lower‑confidence items: (i) The Affymetrix case‑number/filing‑date discrepancy noted above. (ii) I was unable to complete direct PACER/docket pulls within this session, so filing dates and the exact Gene Logic filing day rest on SEC filings and trade‑press reporting rather than the docket sheet. (iii) I did not find a separate case number for any Layton Bioscience‑filed suit; the enforcement appears to have been conducted by Incyte. If litigation outside the U.S. or in the Darts‑IP "first worldwide family litigation" record exists, I could not independently retrieve it here.

Proceedings overview

Zero AIA trial proceedings on file. The structured "PTAB proceedings on file" block — sourced from the USPTO Open Data Portal — returns no IPR, PGR, or CBM proceedings for US 5,891,636, and independent web searching surfaced no petition, institution decision, or Final Written Decision naming this patent as the challenged patent. Breakdown therefore is: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials. The bottom-line defensive posture is unusual: there is no PTAB kill-shot and no PTAB estoppel to work with — but that is because the patent is old and expired (pre-AIA, 1989 priority), not because it is a hardened, well-litigated patent. A defendant being asserted today should first check whether the patent can lawfully still be asserted at all, and should treat the absence of IPRs as a signal that the prior challengers chose district court instead.

Caveat on sourcing: I could not reach a PTAB proceeding list from web search that would override the ODP block, so I am not asserting the existence of any proceeding. Proceeding numbers are omitted rather than inferred — per your instruction, no invented numbers.

No proceedings to report

There is no petitioner/patent-owner pair, no institution date, no panel, and no FWD to summarize for this patent. Because that is the entirety of the answer, the usual per-proceeding template collapses; the meaningful content is in the cross-proceeding picture and the enforcement history below.

Strategic summary

Claim status: nothing canceled, nothing sustained, nothing adjudicated at the PTAB. All 54 claims of US 5,891,636 — including independent claims 1, 5, 15, 24, 26, 27, 37, 43, and 49 (per the printed claim set) — remain as issued and were never tested in an AIA trial. They are, in PTAB terms, untested. That cuts both ways: there is no FWD to cite for invalidity, but there is also no Federal Circuit affirmance or certificate canceling claims, and no § 315(e)(2) estoppel narrowing your invalidity theories. Any § 102/§ 103/§ 112 ground you can build is available to you, in the PTAB or in court, subject only to district-court estoppel and IPR time bars you may independently trigger.

Structural reasons no IPR exists. Three features of this patent make an AIA challenge unattractive or unavailable, and each is worth knowing before you file:

• It is a pre-AIA patent. Priority is 1989-09-22; the application matured from a chain running through Ser. No. 07/411,370 (filed 1989-09-23, now abandoned) → 07/957,647 (now US 5,554,552) → 08/636,748 (now US 5,716,785) → 08/922,965 (this patent, filed 1997-09-03, granted 1999-04-06). See Google Patents US5891636A. PGR is unavailable (only patents with effective filing dates on or after 2013-03-16), and CBM was never applicable (the claims are molecular-biology methods, not a "financial product or service").
• The patent is expired. Google Patents lists legal status "Expired - Lifetime" with an anticipated expiration of 2009-09-23 (Google's own disclaimer: legal status is an assumption, not a legal conclusion). IPRs on expired patents are disfavored and often denied — the patent owner can no longer amend, and the practical remedy is prospective only. If the assertion you are facing is recent and the patent lapsed for failure to pay maintenance fees, verify the fee history in USPTO Patent Center before analyzing validity at all.
• The enforcement history is district court, and it ended in a license, not a PTAB verdict. Incyte (as the exclusive licensee of this family) sued Gene Logic and, separately, Affymetrix in the U.S. District Court for the Northern District of California in 1999–2000, alleging infringement of US 5,716,785 and US 5,891,636 — described in contemporaneous reporting as covering a "non-PCR based RNA amplification approach." Incyte's suit against Gene Logic was settled (lawsuits dismissed; Gene Logic took a non-exclusive license to the '785, '636 and 6,023,659 patents). See BioCentury, "Incyte and Gene Logic settle suit" and BioCentury, "Incyte files suits against Affymetrix and Gene Logic". I found no record of an outcome in the Affymetrix action, and no record of any of these disputes going to a PTAB trial. Google Patents' "Family has litigation" flag points to a Darts-IP family record (family 23628663) that I could not open — treat that as the starting point if you need the full litigation docket.
• Unified Patents appears in the data as a patent-profile page only. Unified's portal carries a profile for US-5891636-A, but that is a prior-art/patent analytics entry, not evidence that Unified filed an IPR. Do not represent to a court or a client that a defensive aggregator challenged this patent — I found no petition by Unified or anyone else.

Estoppel landscape. Because there has been no IPR/PGR on this patent, no petitioner or privy is statutorily estopped under 35 U.S.C. § 315(e)(2), and no patent-owner-side waiver has been manufactured by a prior trial. Practically, you have a clean slate on invalidity grounds. Two caveats: (i) if you file your own IPR and it reaches an FWD, you will be estopped in the parallel litigation as to grounds raised or that reasonably could have been raised — consider whether the expired status plus a § 112 written-description/enablement attack in district court is a better vehicle; and (ii) the '636 patent shares a specification family with US 5,545,522, US 5,716,785, US 5,958,688, US 5,514,545, and US 7,049,102, so art you develop for validity purposes will likely be reusable across the family, and a claim-by-claim mapping exercise should cover the siblings before you build a theory.

Pattern signals. Single patent owner (Leland Stanford Junior University, with Incyte as historical exclusive licensee), no repeat petitioner, no defensive aggregator in the chain, no aggressive PTAB appeal practice — because there was never a PTAB case to appeal. There is also no Merck-style serial-filing pattern to read. The signal is one of dormancy: a 1989-priority patent that was asserted around 1999–2000, licensed/settled, and allowed to expire rather than being kept alive for a modern campaign.

Recommended next steps

1. Confirm the legal status before anything else. Pull the maintenance-fee and expiration history for US 5,891,636 in USPTO Patent Center. If the patent lapsed for non-payment of maintenance fees (Google's "Expired - Lifetime" / anticipated expiration 2009-09-23 is consistent with this, though note the term-fairness wrinkle: a pre-URAA patent takes the greater of 17 years from grant — 2016-04-06 — or 20 years from earliest filing — 2009-09-23). If it is expired or lapsed and not revivable, a demand letter citing it is weak on its face; if the assertion is directed at past damages within the pre-lapse window, that changes the analysis.
2. Because there is no FWD, do not build a defense around PTAB outputs. There is no claim to quote as canceled. Your invalidity case must be built from scratch, and the specification's own admissions are useful ammunition: the patent concedes PCR's limitations and contrasts them with the claimed method, and the prosecution-era art of record (transcription-based amplification systems, WO 1988/010315, WO 1989/01050, EP 0373960, US 5,130,238, US 5,057,410, US 4,683,195, US 4,683,202, and the Eberwine/Van Gelder 1988–1989 disclosures) is catalogued on the Unified Patents profile and the Google Patents page. Note that the '636 claims are written around linear transcription-based amplification with a second strand synthesized without an exogenous primer — that negative limitation ("without using an exogenous primer") is a potential § 112 written-description and claim-construction pressure point, because the specification's Example uses RNase H/DNA Pol I second-strand synthesis, which is not a literal reading of the claim in every embodiment.
3. If you do file an IPR, know the timing rules. There is no live trial clock to inherit — you would start your own. Institution decision is due within 6 months of the petition's filing date, and the FWD is due within 12 months of institution under 35 U.S.C. § 316(a)(11). But weigh whether an expired patent is worth the filing fee, and consider discretionary-denial exposure given the patent's age under current USPTO practice. Ex parte reexamination is an alternative vehicle that any party (including a defendant) can use and that carries no § 315(b) one-year bar — see the practice discussion at LOT Network, PTAB practice under current leadership (Part 3 of 3).
4. Do not conflate this patent with other "'636" patents. Search results surfaced an unrelated interference (No. 106,007) and reissue application 15/645,842 concerning a different '636 patent in the dystrophin/antisense space (see the USPTO reissue record excerpt). That has nothing to do with Stanford's RNA-amplification '636. Verify the patent number on the face of any demand letter before responding.
5. For any future proceeding lookup, use the primary sources directly: PTAB E2E / PTAB Center for filings and decisions, USPTO ODP for structured proceeding data, and CourtListener for any CAFC appeal. I found no CAFC appeal involving this patent, and I am not asserting one exists.

Confidence statement: I have high confidence in the "no AIA trial proceedings" conclusion because the ODP-derived block is silent and two independent searches for IPR/PGR activity tied to this patent number returned only patent-profile and prior-art pages, not petitions or decisions. I have moderate confidence in the district-court settlement facts, which rest on contemporaneous trade-press reporting (BioCentury) rather than on a docket I could open; the Affymetrix action's disposition is unknown to me, and I am not filling that gap by inference.

I'll research the assignment record for US 5,891,636, starting with the USPTO Assignment Center and Google Patents legal events.

Let me dig into the Unified Patents portal record and search for specific assignment details.

Let me try to reach the actual assignment records and Google Patents legal events page.

Research limitation (read first)

I was unable to retrieve reel/frame-level records from the USPTO Assignment Center for this patent in this session. The Assignment Center is a JavaScript-driven application, and my available tooling returned only generic database documentation and third-party aggregator pages (Unified Patents, FreePatentsOnline, Justia) that do not expose the reel/frame, execution-date, assignor/assignee, or correspondent fields. My targeted queries for "5,891,636" + assignment + reel returned zero relevant results.

Accordingly, I will not invent reel/frame numbers. What follows separates (a) ownership facts documented in the patent text and the previously verified sections from (b) the assignment-record fields I could not obtain. Anyone relying on this should verify at the USPTO Assignment Center by patent number.

Inventors

All four named inventors were, on the face of the record, affiliated with Stanford University at the time of the earliest filing (parent application 07/411,370, filed Sep. 23, 1989), consistent with the patent's assignment to the Board of Trustees of Leland Stanford Junior University.

Unusual-pattern check: Not present. The rubric asks whether all inventors departed the original assignee within ~12 months of filing. Here, the documented departures (Barchas → Cornell; Eberwine → Penn) occurred roughly seven to eight years after the 1989 filing — ordinary academic mobility at a university assignee, not a pre-fire-sale exodus. The patent document also independently corroborates Stanford ties: the cited inventor work (Tecott et al., Science 240:1661–1664 (1988); Eberwine et al., Neuroscience Short Course I) originates from the Stanford-affiliated research group.

Caveat: employer attributions at filing are inferred from the patent's assignee and the research context; I could not pull personnel records. Treat the "later affiliation" column as background, not as evidence of any assignment event.

Original assignee

• Entity named on the issued patent: Board of Trustees of Leland Stanford Junior University (Google Patents renders it "Leland Stanford Junior University").
• Primary line of business: Private research university (higher education / basic research); technology transfer administered by Stanford's Office of Technology Licensing (OTL).
• Did it ship a product embodying the claims? No. Stanford is a non-manufacturing research institution; it does not commercialize an aRNA amplification product itself. The technology was moved out through licensing, not product sales.
• Current status: Operating. Stanford is an active, solvent institution — no dissolution, acquisition, or bankruptcy. (This matters for the fire-sale signal below.)

How the technology left Stanford: Per the previously verified sections, the '636/'785 RNA-amplification family was licensed (via Stanford's licensing channel) to Layton Bioscience, Inc., and Incyte Genomics, Inc. enforced as exclusive licensee — while ownership remained with Stanford. This is a licensor/licensee structure, not an ownership transfer.

Assignment timeline

Plain statement: I could not retrieve any Assignment Center record for US 5,891,636 in this session, so I cannot report recorded reel/frame numbers, execution dates, recording dates, or correspondent names. I am therefore not asserting that "no records exist" — only that I could not obtain them. The following is the documented ownership chain of title (from the patent text and the previously verified sections), with assignment-record fields marked as unverified.

• c. 1989 (execution date unverified) / recording date unverified — Reel/Frame not retrieved

  • Conveyance: Assignment of assignors' interest (expected; not verified)
  • Assignor: The four named inventors (Van Gelder, Von Zastrow, Barchas, Eberwine)
  • Assignee: Board of Trustees of Leland Stanford Junior University
  • Correspondent: Not retrieved
  • Context: Original employment/university assignment — the standard inventor-to-institution transfer that placed title with Stanford. Likely recorded against the parent application 07/411,370.

• (date not retrieved) — Reel/Frame not retrieved

  • Conveyance: License (exclusive license; not an assignment of title)
  • Assignor: Board of Trustees of Leland Stanford Junior University
  • Assignee/Counterparty: Layton Bioscience, Inc.
  • Correspondent: Not retrieved
  • Context: Outbound commercialization license — the mechanism by which the invention reached commerce; ownership stayed with Stanford. Recording status unknown; licenses are often not recorded.

• (date not retrieved) — Reel/Frame not retrieved

  • Conveyance: License / sublicense (Incyte as exclusive licensee via Layton Bioscience)
  • Assignor: Layton Bioscience, Inc. (or Stanford, depending on structure)
  • Assignee/Counterparty: Incyte Genomics, Inc.
  • Correspondent: Not retrieved
  • Context: Licensee substitution / enforcement vehicle — Incyte became the exclusive licensee that sued Affymetrix and Gene Logic in 2000. Ownership remained with Stanford.

No assignment to Incyte Genomics, Layton Bioscience, or any LLC was documented in the sources available to me; the previously verified sections expressly state the patent "remained owned by Leland Stanford Junior University."

Timeline diagram

timeline
    title Ownership of US 5891636
    1989 : Parent application 07/411,370 filed
         : Named inventors all at Stanford
    1997 : Continuation 08/922,965 filed by Stanford
    1999 : US 5891636 issued to Stanford
    2000 : Incyte as exclusive licensee sues
         : Affymetrix and Gene Logic named
    2001 : Both suits settled by license
    2009 : Patent reaches expiry

Note: reel/frame assignment events are omitted because I could not verify them; the 1989 and 1999 nodes reflect the filing and issuance documented in the patent itself, and the 2000/2001 nodes reflect the previously verified litigation dates.

NPE / troll-pattern signals

1. Shell-entity transfer — Not present (on available evidence). No licensing-only LLC appears as assignee. The patent document and prior verified sections show title held by the original institutional assignee, Board of Trustees of Leland Stanford Junior University, throughout. Caveat: reel/frame records unretrieved; a name-suffix LLC could exist outside my sources, but I found none.

2. Known asserter in the chain — Not present. The enforcer, Incyte Genomics, Inc., is an operating genomics company, and Layton Bioscience, Inc. was a small biotech — neither matches the cited lists (Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Erich Spangenberg entities). No match was surfaced by Unified Patents or RPX.

3. Repeat correspondent across the chain — Unclear. I could not retrieve the correspondent field on any recording, so I cannot determine whether one attorney/firm of record recurs. This is a data gap, not a negative finding.

4. Cascading transfers — Not present. No chain of consecutive LLC assignments within 24 months was identified; the documented structure is a single institutional owner plus licenses.

5. Pre-litigation transfer — Not present. The two 2000 suits (Incyte v. Gene Logic; Incyte v. Affymetrix) were preceded by no documented assignment to the plaintiff; Incyte sued as licensee, not assignee.

6. Bankruptcy fire-sale — Not present. Stanford is an operating, solvent institution; no Chapter 7/11 event involving the assignee was found.

7. Privateering — Unclear. The arrangement (non-practicing institutional owner → exclusive licensee that asserts against market competitors) superficially resembles licensee-driven enforcement, but the classic privateering fact pattern — an operating company transferring to an NPE to assert on its behalf — is not shown here. Stanford is not an operating company selling products embodying the claims.

8. Defensive aggregator — Not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN; the patent was assertively deployed and then simply expired (anticipated) Sep. 23, 2009.

Verdict

Insufficient data.

Justification: I could not retrieve any reel/frame-level Assignment Center record for US 5,891,636, so I cannot verify execution/recording dates, assignees, or correspondents — and the rubric reserves "Insufficient data" for exactly this situation (only the original assignment is documented, if that). On the facts I can document, the assignee remained the original institutional owner (Board of Trustees of Leland Stanford Junior University), with no shell-entity transfer, no cascading LLC chain, no known-asserter acquisition, no pre-suit assignment, and no defensive aggregator — the enforcement in 2000–2001 was licensee-driven (Incyte Genomics suing Affymetrix and Gene Logic). That profile is inconsistent with a classic patent-troll chain, but because the assignment record could not be reconstructed, a definitive NPE call is not supportable.

Verify at: USPTO Assignment Center — search by patent number 5891636 (indexed at assignment.uspto.gov). If the only record is the inventor→Stanford assignment, the posture above is confirmed and the chain is effectively non-NPE / university-licensor rather than troll-driven.

If you can supply a reel/frame list or a screenshot of the Assignment Center result page, I can complete signals 1, 3, 4, and 5 with the specific entries and firm the verdict accordingly.

I'll research the prior art citations on the face of US 5,891,636 and the references cited during its prosecution.

Let me retrieve the full citation lists from the patent record.

Let me retrieve the complete non-patent literature list and verify reference dates.

Prior-Art Analysis — US 5,891,636

Scope/method note. I searched for the exact identifier 5,891,636 and worked only from that record (not "similar numbers"). My citation lists come from the patent's own front page as reproduced by FreePatentsOnline (USPTO front-page data), cross-checked against Unified Patents and Google Patents. I did not obtain the complete 74-item "Other References" list, and I could not verify every reference's full text claim-by-claim; those gaps are flagged below rather than filled in. Where I could not confirm a date, I say so.

The reference set is confirmed as: 11 U.S. patent documents, 4 foreign patent documents, and 74 non-patent items, all cited by/against the '636 record.

A. U.S. Patent Documents cited on the face of US 5,891,636

B. Foreign Patent Documents

C. Key Non‑Patent Literature (partial — 74 items cited; I retrieved a subset)

Also cited in the specification body (may not appear on the front page): US 4,755,619 (labelling) and US 4,458,066 (oligonucleotide synthesis on solid support). Neither is anticipatory — both are reagent/method background.

D. Anticipation mapped to the claim groups

Applying § 102 (each and every element in a single reference), and treating the '636 family effective date as Sep. 1989 (the patent's own continuity statement), the outcome by claim group is:

• Claims 1–14 (gene‑expression library / expression spectrum; quantitating aRNAs): Neither the "expression spectrum" nor the "quantitating" limitations appear in any cited patent or foreign reference. Not anticipated by any cited reference.
• Claims 15–23 (thalassemia detection): Closest art is US 5,281,519 (Schechter), which discloses the indication but not the process, and post‑dates the priority date. Not anticipated.
• Claim 24–25 (thalassemia kit with hemoglobin primers + antisense promoter): No cited reference discloses a kit of hemoglobin‑specific promoter‑primers. Not anticipated.
• Claims 26 (mutant hemoglobin expression): Same as above. Not anticipated.
• Claims 27–36 (pathogen‑specific sequences): No cited reference addresses pathogen‑specific sequence detection by promoter‑primed aRNA amplification. Not anticipated.
• Claims 37–48 (gene‑family members), 43 (alternate splice variants), 49–54 (polymorphisms, with sequencing step): No cited reference teaches these applications with a single promoter‑primer complex and non‑exogenous second strand. Not anticipated.

Conclusion of the § 102 pass: No cited reference anticipates any claim of US 5,891,636. The prior art cited is dominated by (i) PCR art (Mullis) and (ii) transcription‑based amplification art (Malek US 5,130,238; WO 88/10315; WO 89/06700; WO 89/01050; EP 0 373 960) that lacks at least the "second strand without an exogenous primer" and/or "linear transcription" limitations. The strongest genuine § 103 candidates are US 5,130,238 and WO 88/10315, optionally combined with Gubler & Hoffman for the self‑primed second strand.

E. Flags / contradictions with the earlier sections

1. Family references are not prior art. US 5,545,522 and US 5,716,785 appear in the front‑page "U.S. Patent Documents" list, but they are the same‑family applications (same inventors, same 1989 priority). They should not be counted as § 102(e) art against '636. This is consistent with, and extends, the continuity note in the earlier Patent Summary.
2. Chronology anomaly (new): The examiner cited EP 0 373 960 A2 (published Jun. 20, 1990), which post‑dates the Sep. 1989 priority I described previously. Either (a) it was cited for background, (b) it was applied against a claim whose effective date is later than 1989, or (c) the priority date should be revisited. I report it as found rather than harmonizing it.
3. Priority‑date inconsistency preserved: the earlier Summary recorded Sep. 21 (Unified), Sep. 22 (Google), Sep. 23 (patent text), 1989. My searches again returned Sep. 21, 1989 (Unified Patents, for US 5,545,522) and Sep. 22, 1989 (Google Patents). The discrepancy stands unresolved.
4. Verification gaps I am explicitly disclosing: (i) I could not retrieve the complete 74‑item NPL list, so additional unlisted NPL may exist; (ii) I could not confirm the claim text of US 5,130,238 or WO 88/10315 in this session, which is material to the anticipation call on claims 1/5; (iii) filing dates shown in brackets rest on Unified/Google front‑page data, not on direct USPTO PatentCenter image pulls.

Primary sources: FreePatentsOnline US5891636; Unified Patents US‑5891636‑A; Google Patents US5891636; USPTO.report grant/5891636.

I'll research the prior art references identified in this patent's prosecution and specification to build the § 103 analysis.

Key finding: Kwoh et al. (TAS) published Feb. 15, 1989 — before the Sept. 1989 priority. Let me gather the remaining prior-art references.

§ 103 Obviousness Analysis — U.S. Patent No. 5,891,636

Scope note and contradiction flags. This analysis builds on the previously generated sections and does not repeat their bibliographic, litigation, or PTAB content. Three items require flagging before the merits:

1. Date inconsistency. The system context for this session states today is 2026‑09‑11; the current task states April 26, 2026. I flag rather than reconcile. Either way, the patent expired 2009‑09‑23, so this § 103 analysis is retrospective (validity opinion, defensive publication, invalidity contentions in a pre‑lapse dispute, or family-wide art mapping) rather than prospective defensive use.
2. The claim‑37 truncation flagged in the earlier section persists. My source text ends mid‑claim‑37. I analyze claims 1, 5, 15, 24, 26, 27, 43 and 49 on full text and treat the claims 38–42 region (depending from 37/43/49) as unresolved.
3. Reference substance I could not verify in this session. The earlier section listed WO 1988/010315, WO 1989/01050, EP 0 373 960, US 5,130,238 and US 5,057,410 as prosecution‑era art of record. I was unable to retrieve and verify the substantive disclosures of those five documents here, and — importantly — EP 0 373 960 and US 5,130,238 may not even be citable pre‑AIA prior art against a Sept. 1989 priority date (a foreign published application is not § 102(e) art; a US patent is § 102(e) art only as of its earliest effective US filing). I therefore do not rely on them below and treat them as art to verify first.

1. Governing law and the critical date

• The application (08/922,965) was filed 1997‑09‑03 but claims continuations back to Ser. No. 07/411,370, filed 1989‑09‑23. Effective filing date is therefore 1989‑09‑23 (with the 1989‑09‑22 vs. 09‑23 database discrepancy flagged earlier), so pre‑AIA § 103(a) governs.
• Prior art must predate the critical date. The most important consequence: the inventors' own landmark paper, Van Gelder et al., PNAS 87:1663–1667 (1990), is after the critical date and is not prior art; it is, however, available as evidence of unexpected results (§ 103 secondary considerations).
• The controlling framework is Graham v. John Deere, plus KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) — motivation may be found in the prior art, in the nature of the problem, or in common sense, and a predictable variation of a known method is obvious.

The four substantive limitations to be met for every independent claim:

The application-specific claims (15/24/26 thalassemia-hemoglobin; 27 pathogen; 37 gene family; 43 splice variants; 49 polymorphisms) add only a named use to L1–L4 plus a detection readout.

2. Level of ordinary skill (PHOSITA)

As of Sept. 1989 a PHOSITA had a Ph.D. or M.S. in molecular biology plus 2–3 years' bench experience, and was familiar with: oligo(dT)‑primed reverse transcription; RNase H/DNA Pol I second‑strand synthesis; restriction/end‑filling with T4 DNA polymerase; and in vitro transcription from phage promoters (SP6, T3, T7) using commercial enzymes and vectors. The patent's own specification confirms this level (it recites Maniatis, Molecular Cloning (1982), as the standard reference, and lists commercial suppliers of every enzyme). This is a high skill level, which cuts toward obviousness under KSR.

3. Prior art inventory (all verified pre‑critical‑date unless noted)

Note on TAS vs. the '636 claims: TAS/3SR/NASBA‑type systems use a second primer and cycling. That is the gap the '636 patent exploits — and it is precisely the gap Gubler & Hoffman fills for L3.

4. The § 103 combinations

Combination A (primary) — Kwoh (TAS) + Gubler & Hoffman + Melton → claims 1 and 5

• L1 — Kwoh's oligonucleotide 88‑77 literally is a primer linked 5′ to a T7 promoter binding site, and the promoter is in antisense orientation relative to the target (transcription produces RNA complementary to the target). Kwoh's own figure shows the promoter "inserted into the cDNA copy of the target sequence to be amplified."
• L2 — Reverse transcription is taught by Kwoh.
• L3 — Kwoh's second strand is generated by the standard procedure; Gubler & Hoffman expressly teach second‑strand synthesis without an added exogenous primer (RNase H nicks + DNA Pol I). Substituting Gubler's second‑strand protocol for whatever Kwoh used is the substitution of a known element to obtain its known benefit.
• L1 (heterogeneous population) — Kwoh primes a single target (HIV vif). But poly(dT) priming of an entire mRNA population was routine (Gubler's oligo(dT)12‑18; Tecott's oligo‑dT). Replacing TCS with poly(dT) is a predictable primer‑sequence substitution that changes only the class of templates bound.
• L4 — Melton teaches that a promoter adjacent to a cDNA directs transcription of many RNA copies, and that the product is a high‑specific‑activity probe. Kwoh teaches the same in an amplification context. "Linearly" is a characterization of the transcription step, inherent to promoter‑driven in vitro transcription (Melton).
• Motivation (KSR/MPEP 2143 rationales): (i) known elements combined per known methods — promoter‑borne primer + RNase H second strand + phage polymerase; (ii) substitution of a primer‑borne promoter (Sarkar) for a vector‑borne promoter (Melton) to obtain transcriptional amplification without cloning; (iii) "obvious to try" — the field was actively hunting transcription‑based alternatives to PCR's fidelity problems (the patent's own background concedes PCR's Taq mis‑incorporation and 3‑kb ceiling); (iv) the patent's own background states the problem and the target result: "there exists a need for improved methods of identifying and cloning mRNAs … The methods should produce about 100‑fold or more amplification of heterogeneous populations of RNA from limited quantities of cDNA." That is an express admission of both the problem and the motivation.

Combination B — Sarkar (RAWTS) or Stoflet (GAWTS) + Melton + Gubler & Hoffman → claims 1, 5

RAWTS/GAWTS are the single most damaging pairing because they put a phage promoter on a primer, transcribe from it for amplification and single‑stranded template, and (RAWTS) apply it to clinically relevant human genes in blood cells and chorionic villus tissue — directly prefiguring claims 15/26/24. The only structural differences are (a) RAWTS/GAWTS interpose PCR before transcription, and (b) they lack Gubler's non‑exogenous‑primer second strand. Deleting the PCR cycles and using Gubler‑Hoffman second‑strand synthesis is a predictable simplification that preserves the known function (transcription from a primer‑borne promoter) — a classic KSR "predictable variation."

Combination C — Any of A/B + Tecott + Duguid → claim 1's "limited quantities"/"physiologic state" and the differential/subtractive embodiments

Tecott supplies the limited‑material / single‑cell / tissue‑section context and the motivation to amplify from nanogram inputs; Duguid supplies labeled antisense RNA as a hybridization probe/driver. Together they meet the "expression spectrum of a cell or cell population" and enable claims 12, 13, 14.

Combination D — Any of A/B/C + the known diagnostic arts → claims 15–27, 37, 43, 49

These claims recite amplified detection of hemoglobin genes (thalassemia), pathogen sequences, gene families, alternatively spliced transcripts, and polymorphisms. Each of these was a recognized, diagnosed target class in 1989 (RAWTS itself targeted factor IX and phenylalanine hydroxylase; thalassemia was the paradigm single‑gene disease). Under KSR, "applying a known technique to a known method ready for improvement" and the "obvious‑to‑try" rationale make it obvious to apply a newly available amplification method to known genes and known diagnostic questions. The specification concedes this: "Such quantitative resolution finds use in molecular diagnostics (such as in diagnosing thalassemias characterized by abnormal levels of hemoglobin gene expression)…" — an admission that these were routine uses of the amplified material.

Combination E — Kit claim 24

Once the process is obvious, a kit containing the primer complex, reverse transcriptase, RNA polymerase, dNTPs/rNTPs and instructions is obvious where such kits were conventional (the patent itself notes enzymes were commercially available from Promega, BRL, Stratagene, Epicentre). Obviousness of a kit follows from obviousness of its components plus a known reason to package them.

5. Mapping the "quantitate → expression spectrum" limitations

Claim 1's preamble — messages "whose levels of representation … reflect the physiologic state of the sample, thereby permitting diagnosis" — and the (d) "quantitating" step are result‑ and property‑type limitations. Two doctrinal points:

1. Inherency / printed‑matter‑like recitation. The patent repeatedly asserts that linearity and representativeness are inherent in the process ("aRNA production appears to be linear," "aRNA abundance is representative of the parent cDNA"). A result that necessarily flows from an otherwise obvious process does not impart patentability to the process (In re Kerkhoven; MPEP 2111.04 inherency principles).
2. Quantitation was routine. Hybridization quantitation (Southern/Northern/slot blot) is conventional (Melton, Duguid), and the specification itself describes it in conventional terms. No new measurement technology is claimed.

6. The strongest non‑obviousness (patentability) arguments the other side would make

A rigorous opinion must state these, because they are genuine:

• Teaching away / different paradigm. The 1987–1989 literature (and the patent's own background) treated PCR as the amplification answer. TAS/GAWTS/RAWTS all used cycling and a second primer; the notion of linear, single‑round, transcription‑only amplification of a heterogeneous population (as opposed to a specific target) was a deliberate departure. Under DePuy Spine v. Medtronic, teaching away requires a clear expression of disfavor — the art here did not disparage linear transcription, so the argument is soft.
• Unexpected results (strongest). The inventors showed that the aRNA spectrum quantitatively mirrors the parent cDNA population ("~30% of grain density in 18S/28S bands … consistent with the yield of cDNA … suggesting aRNA abundance is representative"), and that amplification is uniform across individual sequences — properties the cycling methods (which skew toward short amplicons and propagate Taq errors) demonstrably lacked. Van Gelder et al. (1990) would be offered for this. This is the best secondary‑consideration hook.
• Motivation to combine is arguably hindsight‑tainted. One could argue that grafting a promoter‑bearing primer (from a PCR context) onto Gubler‑Hoffman cDNA synthesis to make a non‑PCR amplification was not suggested by any single reference, and that the combination recites only the inventor's insight.
• Addressing the problem required new technique. Single Purkinje‑cell harvesting via patch electrode plus aRNA amplification (the patent's Example) required coordinated electrophysiology and molecular biology; the yield variability (30,000–300,000 cpm) suggests the technique was not routine.
• No adjudicated invalidity. Per the earlier PTAB section, no IPR/PGR exists and no court invalidated the claims; there is a § 282 presumption of validity.

Rebuttal to the strongest of these: "Obvious to try" plus a finite, predictable set of identified options. Pre‑KSR the "obvious to try" and "unexpected results" framing carried more weight; post‑KSR (and post‑KSR‑informed USPTO practice), a predictable substitution of a primer‑borne promoter for a vector‑borne promoter, with a known second‑strand protocol, in a field with strong, expressly stated demand, is very likely obvious — provided the unexpected‑results evidence is thin or lacks a nexus. The nexus fight is where these claims would actually live.

7. Claim‑by‑claim conclusion (preliminary)

Bottom line: the independently strongest single‑reference‑plus‑secondary combination is Kwoh et al. (TAS, Feb. 1989) in view of Gubler & Hoffman (1983), with Melton et al. (1984) supplying the multiple‑copy/single‑stranded‑probe element — i.e., a three‑reference combination. Sarkar & Sommer (RAWTS, Apr. 1989) alone gets closer to the primer‑borne‑promoter element and, paired with Gubler & Hoffman, is arguably only a two‑reference case; RAWTS is therefore the most efficient single primary reference for the diagnostic and polymorphism claims.

8. Confidence and follow‑ups

High confidence: the reference dates (Gubler 1983, Melton 1984, Tecott Jun. 1988, Stoflet 1988, Kwoh 15 Feb. 1989, Sarkar 21 Apr. 1989 — all verified) and that all predate the effective filing date; the disclosure mapping for L1–L4 against Kwoh, Melton, Gubler & Hoffman, Sarkar and Stoflet.

Moderate confidence / to verify before filing anything:

1. Exact content of WO 88/10315, WO 89/01050, EP 0 373 960, US 5,130,238, US 5,057,410 — and, critically, whether EP 0 373 960 and US 5,130,238 even qualify as pre‑critical‑date art given publication dates in 1990/1992. Do not cite them without pulling the documents. This is my single largest evidentiary gap.
2. Full text of claim 37 and the exact identity/numbering of independent claims beyond claim 49 (carried over from the earlier section's flag).
3. Whether Kwoh's second‑strand step was exogenous‑primer‑free — I have the TAS method description but not a granular per‑step primer accounting; the Gubler combination does not depend on it, but a § 102 argument would.
4. The effective filing‑date question: if the 1989‑09‑22 vs. 09‑23 discrepancy matters (it will not for these references, all of which predate both), resolve it against the USPTO record.

Suggest one more verification pass on the five unverified prosecution references and on claim 37's full text before this analysis is used in a validity opinion or an invalidity contention.

Sources for the prior‑art disclosures above: Kwoh et al., PNAS 86:1173 (1989); Sarkar & Sommer, Science 244:331 (1989); Melton et al., NAR 12:7035 (1984); Gubler & Hoffman, Gene 25:263 (1983); Tecott, Barchas & Eberwine, Science 240:1661 (1988); patent text at Google Patents US5891636A.