US 11298320

I'll search for this specific patent number as instructed.

Let me verify the claim text and check for any CAFC 2026 docket activity.

Let me try to retrieve the full claim set to confirm the claim count and the remaining dependent claims.

US Patent 11,298,320 B2 — Analyst Summary

Source note: I queried the open web for this exact number (Google Patents, USPTO.report, Justia, FreePatentsOnline, and litigation filings via CourtListener/Unified Patents/bigmoleculewatch). No Federal Circuit 2026 docket directly naming this patent surfaced. I have not accessed the USPTO PatentCenter/Patent Public Search certified copy directly. Where I quote claim language, it is taken verbatim from litigation documents (complaints/answers) rather than from the printed patent, and I flag that.

1. Bibliographic data

Two record discrepancies worth flagging (I am reporting, not correcting):

• The Google Patents reassignment entry for the May 25, 2021 filing lists assignors as "GIESBRECHT, NOELLE; JEFFS, LLOYD; MACLACHLAN, IAN; PALMER, LORNE R.," whereas the patent front page and Justia list "Cory Giesbrecht." Both spellings appear in the record set as retrieved.
• The inventor surname appears both as "Maclachlan" (Google Patents) and "MacLachlan" (Justia/litigation).

2. Continuity (from the patent's own cross-reference section, quoted in the authoritative text)

This is the terminal continuation of a long chain:
17/330,209 (filed 2021‑05‑25) ← cont. of 17/203,220 (Mar. 16, 2021) ← cont. of 16/576,587 (Sept. 19, 2019) ← cont. of 16/035,144 (July 13, 2018) ← cont. of 15/299,413 (Oct. 20, 2016) ← cont. of 14/304,578 (June 13, 2014, issued as US 9,504,651) ← cont. of 13/684,066 (Nov. 21, 2012, issued as US 9,492,386) ← cont. of 12/965,555 (Dec. 10, 2010, issued as US 8,329,070) ← divisional of 10/611,274 (June 30, 2003, issued as US 7,901,708) ← priority to provisional 60/392,887 (June 28, 2002).

This explains the "Expired – Lifetime" status: the enforceable term runs from the 2002 priority family, expiring ~June 30, 2023.

3. Abstract (verbatim)

"The present invention provides apparatus and processes for producing liposomes. By providing a buffer solution in a first reservoir, and a lipid solution in a second reservoir, continuously diluting the lipid solution with the buffer solution in a mixing chamber produces a liposome. The lipid solution preferably comprises an organic solvent, such as a lower alkanol."

4. Independent claims — plain-language overview

⚠️ Confidence caveat: I could confirm that the '320 patent has two independent claims, claims 1 and 18, and I have their text as quoted in the parties' litigation papers. I could not retrieve the complete claim set (number of dependent claims, and the full text of claim 18's preamble elements) from an authoritative patent-office source. Treat the claim language below as accurate-but-secondary-sourced.

Claim 1 — Apparatus for producing a nucleic-acid-encapsulating lipid vesicle

An apparatus comprising three things:

1. First reservoir holding an aqueous solution that includes a nucleic acid;
2. Second reservoir holding an organic lipid solution, where the lipids are solubilized in a lower alkanol at about 75% v/v to 100% v/v; and
3. A pump mechanism configured to pump the two solutions into a mixing chamber at different flow rates relative to each other;

…wherein the mixing chamber is configured so the two streams are introduced as opposing flows at about 180° relative to each other and mixed within the chamber to instantaneously produce a lipid vesicle encapsulating the nucleic acid, by diluting the lower alkanol concentration in the organic lipid solution.

In plain terms: a two-reservoir, T-junction style mixer-apparatus, where the lipid is dissolved in very high (75–100% v/v) alkanol, the two streams meet head-on at ~180°, and vesicle formation + nucleic acid encapsulation happen in one instantaneous dilution step.

Claim 18 — Apparatus for producing a nucleic-acid-encapsulating lipid vesicle

Same general architecture (reservoirs for the nucleic-acid-containing aqueous solution and the alkanol/lipid solution; a pump mechanism feeding the mixing chamber at different flow rates relative to each other; the chamber mixing the streams to instantaneously produce a nucleic-acid-encapsulating lipid vesicle by diluting the alkanol), except that the introduction angle is "between 90° and 180° relative to each other" rather than "about 180°."

Practical distinction between the two independents: claim 1 is narrower on geometry (about 180°, opposing flows) with a specified alkanol range of about 75–100% v/v; claim 18 is broader on geometry (90°–180°) — I could not confirm from an authoritative source whether claim 18 also recites the 75–100% v/v alkanol limitation (the retrieved litigation quotation showing its preamble omitted those elements).

5. Specification context (from the authoritative text provided)

• The disclosure is an apparatus and process patent: two reservoirs → pump → T-connector mixing chamber → continuous, stepwise dilution of an ethanolic lipid stream by an aqueous buffer to form liposomes "substantially instantaneously."
• Preferred liposome size 50–550 nm; mean <200 nm (e.g., ~100 nm) without extrusion, sonication, or microfluidization.
• Preferred four-lipid SPLP formulation: DSPC : Chol : PEG‑DSG : DODMA at about 20:45:10:25 (mol).
• Encapsulation efficiency up to ~90% on mixing; dilution step raises entrapment from ~30–40% to ~70–80%.
• Explicitly non-turbulent design: Reynolds number < 2000, shear rate ~500–3300/s at ~0.075–0.3 L/min per line (Examples, FIGS. 13–14), contrasted with the turbulent static-mixer approach of PCT WO 01/05373 (Knopov).
• Differential over the art distinguished in the Background: U.S. 5,478,860 (Wheeler et al., Dec. 26, 1995) microemulsions; and WO 01/05373.
• Prosecution-history significance (asserted by adverse parties): Pfizer/BioNTech's counterclaims allege that the earlier family patents ('708, '070, '386) all claimed mixing at "about equal flow rates," and that the '320 and '098 patents are the first in the family to claim "different flow rates relative to each other," filed May 25, 2021 — less than two months after an April 2021 CNN interview showing Pfizer's T-mixer. This is a party allegation, not an adjudicated fact.

6. Litigation posture relevant to this number

• Asserted in Arbutus Biopharma Corp. v. Pfizer Inc. / BioNTech SE, U.S. District Court for the District of New Jersey, alongside US 9,504,651; 8,492,359; 11,141,378; and 11,318,098 (complaint announced April 4, 2023).
• Google Patents lists three D.N.J. case identifiers: 3:23-cv-04200, 3:23-cv-01876, and 2:23-cv-01876 (reported literally as given).
• A claim construction ruling in the D.N.J. action was issued Sept. 9, 2025 (per Arbutus Form 8-K). Note: that 8-K summary, as retrieved, lists the patents as "9,504,561; 8,492,359; 11,141,378; 11,298,320; 11,318,098" — reported as-is; the '651 number appears elsewhere in the record with the more common form.
• Federal Circuit 2026 activity: the only 2026 CAFC matter I found in this family is Arbutus Biopharma Corp. v. Moderna, Inc., No. 26-1581 (appeal from D. Del. No. 1:22-cv-00252-JDW; notice of appeal filed Mar. 24, 2026; briefed through Aug. 21, 2026; settled as to money with the §1498 government-contractor defense preserved for appeal). The reported D. Del. judgment patents were US 8,058,069; 8,492,359; 8,822,668; 9,364,435; 9,504,651; and 11,141,378 — the '320 patent is not named. So: I found no CAFC 2026 docket entry specifically identifying US 11,298,320, and I cannot confirm that the '320 patent is on appeal anywhere.
• A third docket fragment (SDNY, gov.uscourts.nysd.576814) contains Pfizer/BioNTech counterclaims styled against the '320 and '098 patents (including Count IV, declaration of non-infringement of the '320 patent); I did not independently verify the court/case caption beyond the URL string.

7. Explicit uncertainties

1. Full claim set not verified. I confirmed two independent claims (1 and 18) but do not have an authoritative total claim count or the dependent-claim text. Do not rely on the absence of other claims.
2. Claim language is litigation-transcribed, not read from the printed patent's claim column. Minor typographical artifacts appear in the source (e.g., "nucleic add" appears once for "nucleic acid").
3. Assignee chain/fee status is per Google Patents' disclaimer-laden "assumption" data and may not reflect the current recorded owner (Arbutus/Genevant licensing arrangements are referenced in litigation but not reflected in the bibliographic record).
4. No IPR/PTAB proceeding against this number appeared in my searches; absence of evidence here is not evidence of absence.
5. The authoritative patent text supplied to me contains the abstract, specification and drawings but not the claims column, consistent with uncertainty #1.

I'll research litigation involving US 11,298,320 using multiple sources.

Found significant litigation. Let me dig deeper into the specific cases and case numbers.

Let me verify the Acuitas D.N.J. case and the ambiguous case numbers from the patent record.

Litigation Involving U.S. Patent No. 11,298,320 ("the '320 Patent")

Bottom line: Yes — litigation is known. The '320 patent has been asserted in one affirmative infringement action (Arbutus/Genevant v. Pfizer/BioNTech) and challenged in one declaratory-judgment action (Acuitas v. Genevant/Arbutus). Both are in the District of New Jersey. Below are the details, with the sources I relied on and explicit flags where verification is incomplete.

1. Arbutus Biopharma Corp. & Genevant Sciences GmbH v. Pfizer Inc. & BioNTech SE (affirmative infringement suit)

Grounding sources:

• Arbutus press release, Apr. 4, 2023 (names all five patents, incl. 11,298,320): https://www.tipranks.com/news/press-releases/arbutus-biopharma-and-genevant-sciences-file-patent-infringement-lawsuit-against-pfizer-biontech
• Docket sheet: https://dockets.justia.com/docket/new-jersey/njdce/3:2023cv01876/[510890](/patent/510890)
• CourtListener docket (Arbutus Pharma Corp. v. Pfizer Inc., 3:23-cv-01876): https://www.courtlistener.com/docket/67142175/323/1/arbutus-pharma-corp-v-pfizer-inc/
• BioNTech and Arbutus annual/quarterly disclosures confirming the five asserted patents and pending status: https://investors.BioNTech.de/static-files/20b5b522-3d8b-4057-a406-59b5e602bdd0 and https://investor.arbutusbio.com/static-files/b24c9cf7-dd55-412a-9f75-1f72bb476016

2. Acuitas Therapeutics Inc. v. Genevant Sciences GmbH & Arbutus Biopharma Corp. (declaratory-judgment challenge)

This is a two-stop procedural history:

2a. Original filing — S.D.N.Y. Acuitas filed a declaratory-judgment action on March 18, 2022 in the U.S. District Court for the Southern District of New York (courtlistener docket gov.uscourts.nysd.576814; DrugPatentWatch lists it as filed 2022-03-18, terminated 2023-08-07, cause 28:2201dj). Acuitas sought declarations that Comirnaty does not infringe, and that nine Arbutus/Genevant patents are invalid. Arbutus/Genevant moved to dismiss for lack of subject-matter jurisdiction (no actual controversy). Acuitas amended its complaint Sept. 6, 2022; motion to dismiss fully briefed Nov. 16, 2022.

2b. Refiled — D.N.J. After the motion to dismiss was briefed, Acuitas voluntarily dismissed the SDNY action on August 4, 2023 and refiled in the District of New Jersey.

Grounding sources:

• Big Molecule Watch (Kirkland) — Acuitas DJ complaint in D.N.J. naming the ten patents incl. 11,298,320: https://www.bigmoleculewatch.com/tag/arbutus-biopharma/ and the Acuitas D.N.J. complaint PDF: https://www.bigmoleculewatch.com/wp-content/uploads/sites/2/2023/08/DNJ-3-23-cv-04200-1.pdf
• Arbutus 10-Q describing the SDNY filing, the motion to dismiss, and the refiling in D.N.J.: https://investor.arbutusbio.com/static-files/f1014a8e-fd6d-40b7-a1d7-9a8f38559fec
• DrugPatentWatch litigation table (shows both the SDNY and D.N.J. Acuitas actions): https://www.drugpatentwatch.com/p/litigation/drugname/index.php?query=patisiran+sodium
• SDNY docket excerpts (gov.uscourts.nysd.576814) describing Acuitas's DJ action and the June 3, 2022 notice identifying the then-just-issued '320 patent: https://storage.courtlistener.com/recap/gov.uscourts.nysd.576814/gov.uscourts.nysd.576814.44.0.pdf

3. Notes, flags, and things I could NOT confirm

• Discrepancy in the patent record itself. The Google Patents litigation section for US 11,298,320 lists three New Jersey entries: 3:23-cv-04200, 3:23-cv-01876, and 2:23-cv-01876. Per your instruction not to auto-correct identifiers, I am reporting all three literally. 3:23-cv-04200 maps to the Acuitas DJ action and 3:23-cv-01876 maps to the Pfizer/BioNTech action. I could not independently verify 2:23-cv-01876 — it may be a duplicate docket under a different Newark/Trenton vicinage prefix for the same dispute, but I have no source confirming it as a separate case. Treat it as unverified.
• The worldwide family litigation link from the patent record: https://patents.darts-ip.com/?family=30000947
• The '320 patent was NOT asserted in the Moderna actions. The Delaware Moderna case (Arbutus Biopharma Corp. v. Moderna, Inc., D. Del. 1:22-cv-00252, filed Feb. 28, 2022) asserted 8,058,069; 8,492,359; 8,822,668; 9,364,435; 9,504,651; and 11,141,378 — not the '320. Those Moderna matters were resolved by a March 3, 2026 settlement ($950M noncontingent + up to $1.3B contingent), with a related Court of Federal Claims action filed March 19, 2026 under 28 U.S.C. §1498. None of the sources I retrieved tie 11,298,320 to those proceedings.
• No PTAB proceeding found for the '320 patent specifically. The searches I ran returned no IPR/PGR/post-grant review record naming 11,298,320. This is an absence of evidence, not proof none exists; I did not query PTAB's Patent Trial and Appeal Board Endpoint/docket directly before hitting the search limit, so I cannot rule out a filed petition.
• Verification limits. I reached my tool-step limit before I could pull PACER/Unified Patents case pages for the Acuitas D.N.J. matter directly. The Pfizer/BioNTech case details are well corroborated across multiple court filings and party disclosures; the Acuitas D.N.J. outcome is the weakest-supported item and should be re-verified against PACER (D.N.J. 3:23-cv-04200) or https://portal.unifiedpatents.com/litigation/caselist before relying on it.

Summary table

I'll start by verifying the structured data against web sources, since the ODP block reports no AIA trials for this patent.

Let me dig deeper on the specific patent number and its family's PTAB history.

Let me check for IPRs on the closely related sibling patents and any Acuitas/Pfizer challenges.

PTAB proceedings on file

Bottom line up front: the structured "PTAB proceedings on file" block for US 11,298,320 returns zero AIA trial proceedings, and my independent web checks found no IPR, PGR, or CBM petition ever filed against this patent — not by Moderna, not by Pfizer/BioNTech, not by Acuitas. I found nothing to contradict the ODP ingest, so the default holds: no PTAB activity on file.

Proceedings overview

Total AIA trial proceedings on US 11,298,320: 0 (0 active · 0 claims invalidated · 0 claims sustained · 0 settled · 0 institution denied). The U.S. validity fight over this patent is happening entirely in district court (D.N.J. Nos. 3:23-cv-01876 and 3:23-cv-04200, per the litigation links in the ODP block), and the patent itself is reported by Google Patents as "Expired – Lifetime," anticipated expiration 2023-06-30 — roughly fourteen months after it issued on 2022-04-12. The defensive posture for a defendant today is therefore not "the patent is hardened by surviving IPRs" and not "claims are cancelled," but rather: a short-lived, administratively untested apparatus patent that has now run its term. The absence of any IPR is largely an economic signal — a patent with ~1 year of life remaining when challenged costs a petitioner $500k–$1M+ and 12–18 months to kill, which is why nobody filed.

No proceeding to report on the '320 itself

There is no ### {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} entry to write for US 11,298,320. Anything below is adjacent context on different patents in the same family and confers no § 315(e)(2) estoppel of any kind on the '320's claims.

Adjacent PTAB proceedings (different patents — NOT US 11,298,320)

IPR on U.S. Pat. No. 9,404,127 (the "'127 patent") — ModernaTX, Inc. v. Arbutus Biopharma Corp.

• Type: Inter Partes Review (petition number not confirmed in the sources I reviewed; the '127 IPR is one of the three Arbutus-side IPRs — IPR2018-00680, IPR2018-00739, and IPR2019-00554 — that Arbutus's own litigation filings cite as its prior Office proceedings).
• Filed: 2018-02-21 (petition requesting review of all claims of the '127 patent, on anticipation and/or obviousness).
• Status: FWD issued; all 22 claims held unpatentable as anticipated; later vacated/remanded for Arthrex and reinstated on appeal.
• Judge panel: Not confirmed in the sources reviewed.
• Petition grounds: § 102 anticipation by Arbutus's own earlier U.S. Pat. No. 8,058,069 (filed 2009-04-15, priority 2008-04-15), and § 103 in the alternative.
• Institution decision: Instituted 2018-09-12 (per Arbutus's own 10-K disclosure). The Board found the '069 patent was § 102 prior art to the '127 patent notwithstanding common ownership and overlapping inventors.
• Final Written Decision: 2019-09-10 — all claims 1–22 unpatentable as anticipated by the '069 patent. The Board found both patents "directed to the same purpose (providing SNALP, methods of making and delivering SNALP)" and found several components in common. This is the single most-cited adverse PTAB outcome in any Arbutus LNP proceeding.
• Settlement / termination: N/A.
• Appeal: Appeals to the Federal Circuit (caption Arbutus Biopharma Corp. v. ModernaTX, Inc.; docket number not confirmed in the sources I reviewed). Per Arbutus's Form 10-K: the decision "was vacated and sent back (remanded) to the PTAB for a rehearing" pending United States v. Arthrex; the matter sat in abeyance until the Supreme Court decided Arthrex on 2021-06-21, after which the Federal Circuit reinstated the appeal sua sponte and Arbutus elected to waive its Arthrex-based challenge. A CAFC case summary of Arbutus Biopharma Corp. v. ModernaTX, Inc. confirms the Board's all-22-claims anticipation finding, but I could not confirm the final mandate language — flagging that uncertainty rather than guessing.
• Defensive value for the '320: Indirect but real. It establishes that Arbutus's later-issued continuation claims in this portfolio have been wiped out by earlier Arbutus patents, and — more usefully — Arbutus's own PO arguments ("the effects of making changes to the proportion of other components in the lipid particle would be unpredictable") are now being flipped against the '320 as § 112 written-description/enablement admissions (see below).

IPR2018-00680 and IPR2019-00554 — Arbutus LNP patents

• Type: Inter Partes Review.
• Status: Appear as Arbutus-side prior Office proceedings, cited in Acuitas's and Pfizer/BioNTech's pleadings. I could not confirm petitioner identity, challenged patent, institution dates, or outcomes for these two numbers from the sources retrieved. Do not rely on them without pulling the PTAB records directly. Confirmed starting points: PTAB E2E, Google Patents – US11298320.
• Defensive value for the '320: None directly; no estoppel flows to the '320 from these.

The '320's validity is being litigated, not petitioned

Because there are no AIA trials, a defendant's real roadmap is the district court record:

1. Acuitas Therapeutics, Inc. v. Genevant Sciences GmbH & Arbutus Biopharma Corp., D.N.J. (DJ action filed 2023-08; counterpart S.D.N.Y. action filed 2022-03-18). Acuitas seeks a declaration that the '320 is invalid and not infringed, and pleads with specificity:

• § 102/§ 103: Quake et al., WO 2002/040874 (published 2002-05-23); Sample et al., WO 1998/051278 (published 1998-11-19); and Semple et al., Efficient Encapsulation of Antisense Oligonucleotides in Lipid Vesicles Using Ionizable Aminolipids, 1510 Biochimica et Biophysica Acta 152 (2001). (Acuitas complaint, Count on the '320 patent, ¶¶ 187–193 — retrieved via Big Molecule Watch PDF.)
• § 112: written description, enablement, and indefiniteness, built in part on Arbutus's own IPR2018-00739 Patent Owner Response at 18. Acuitas specifically attacks "lower alkanol[s]," "flow rates," and "cationic lipid[s]" as lacking reasonable certainty. Note that Acuitas asserts independent claims 1 and 18; the '320 has only two independent claims.

1. Arbutus/Genevant v. Pfizer Inc. & BioNTech SE, D.N.J. No. 3:23-cv-01876 (filed 2023-04-04) — asserts the '320 (and '098, '651, '359, '378). The infringement theory rests on public descriptions of Pfizer's "T-mixer" manufacturing skids (a CNN interview and Bourla's book are pleaded as evidence). Pfizer/BioNTech counterclaimed for invalidity. A Markman hearing was held 2024-12 and the court's ruling issued September 2025, which Genevant characterizes as generally favorable (Roivant investor materials).
2. Litigation links in the ODP block: 3:23-cv-04200, 3:23-cv-01876, 2:23-cv-01876. No defensive aggregator (Unified Patents, RPX, etc.) appears in the chain — this is brand-name pharmaceutical litigation, not NPE activity.

Strategic summary

Claim status of US 11,298,320: 100% UNTESTED at the PTAB. Claims 1 and 18 (the only independent claims) and their dependents stand exactly as issued on 2022-04-12. Nothing has been cancelled; nothing has been sustained after challenge; nothing is estopped. Contrast that with sibling U.S. Pat. No. 9,404,127, where all 22 claims were held unpatentable on 2019-09-10 as anticipated by Arbutus's own '069 patent — the family has a demonstrated vulnerability to its own earlier filings, but the '320 has never been run through that gauntlet.

Estoppel landscape: there is none, and the § 315(b) doors are largely shut. Because no IPR was filed, § 315(e)(2) estoppel does not attach to any petitioner or privy as to the '320. That cuts both ways:

• For a defendant: the full prior-art toolbox remains open in district court — no "raised or reasonably could have raised" constraint on § 102/§ 103 grounds. The Quake, Sample, and Semple references Acuitas is already deploying are available to anyone.
• Against a would-be petitioner: Arbutus served its Pfizer/BioNTech infringement complaint on 2023-04-04, so Pfizer/BioNTech's one-year § 315(b) window closed around 2024-04-04. Moderna's global dispute resolved in the March 2026 settlement ($950M noncontingent payment plus up to $1.3B contingent; Arbutus received ~$178M on 2026-07-08), so no Moderna petition is coming. A DJ plaintiff such as Acuitas does not itself trigger § 315(b) absent service of an infringement complaint — worth checking whether Arbutus counterclaimed for infringement in the D.N.J. action, which would start that clock.

Pattern signals. Arbutus/Genevant are aggressive, serial enforcers — five U.S. patents against Pfizer/BioNTech, nine-plus against Moderna across two suits, and parallel UPC, Canadian, Japanese, Swiss, and UK actions (three new international suits filed July 2026). But they have never petitioned or been petitioned on the '320 at the PTAB, and the company's own filings frame the COVID-vaccine suits as damages-only (no injunction sought as to the U.S. vaccines). Moderna's IPRs against the particle-composition patents (2018–2019) were a different generation of patents, and Arbutus did litigate those to appeal rather than settling early.

The dominant fact for any defendant: the patent is expired. Google Patents lists US 11,298,320 as "Expired – Lifetime," with anticipated expiration 2023-06-30 (20 years from the 2003-06-30 filing of parent application 10/611,274; priority claimed to provisional 60/392,887, filed 2002-06-28). Verify against USPTO Patent Center whether any patent term adjustment moved that date — but note the practical consequences:

• No injunction is available for post-2023-06-30 conduct; the case is a past-damages case only.
• § 286 caps recovery at six years before the 2023-04-04 complaint — i.e., roughly 2017-04-04 through 2023-06-30. The asserted apparatus claims are also a process/apparatus pair with the sibling '098 method patent, so direct infringement of the '320 must be tied to making the accused product using the claimed apparatus, not to selling or administering the vaccine.
• Any § 154(d) provisional-rights theory for pre-issuance conduct would require the published application's claims to be substantially identical to the issued '320 claims — a separate fight worth running down in the file history.

Recommended next steps

1. Do not treat this as an IPR-track patent. There is no FWD to cite and no cancelled claim to wave. Write your invalidity case for the district court, where Acuitas has already front-loaded the art (Quake WO 2002/040874; Sample WO 1998/051278; Semple 2001) and the § 112 attack on "lower alkanol," "flow rates," and "cationic lipid."
2. Pull the three Arbutus-family IPR records directly — PTAB E2E for IPR2018-00680, IPR2018-00739, IPR2019-00554 and the '127 IPR (FWD 2019-09-10) — to harvest (a) Arbutus's § 112 "unpredictability" admissions for use against the '320, and (b) the exact petitioner/patent/outcome mapping I could not confirm. Docket-alarm or Docket Navigator searches on "11,298,320" should be run to double-confirm the negative.
3. Attack the term date and the damages window first. Confirm PTA/terminal-disclaimer history at USPTO Patent Center for US 11,298,320. If expiration is 2023-06-30, move to limit damages to the 2017-04-04 → 2023-06-30 window and knock out any forward-looking relief, royalty base for post-expiry doses, or § 271(b)/(c) inducement theory premised on ongoing sales.
4. Check § 315(b) status for your own entity before considering a petition. If you were served with a complaint asserting the '320 more than one year ago, an IPR is time-barred — and given the 2023-06-30 expiration, a 2026 petition would be an economically irrational exercise (though the Board does institute on expired patents using Phillips construction for past-damages purposes).
5. Monitor the D.N.J. validity track, not the PTAB. The Acuitas DJ action (D.N.J. 3:23-cv-04200) and Pfizer/BioNTech counterclaims (3:23-cv-01876) are where the '320's claims will live or die, with the September 2025 Markman ruling as the current claim-construction benchmark.

Confidence caveats: I could not confirm the petition-number-to-patent mapping for IPR2018-00680/IPR2018-00739/IPR2019-00554, the APJ panels, or the final Federal Circuit disposition of the '127 IPR. The expiration date is taken from Google Patents' legal-status field, which that page itself flags as an assumption and not a legal conclusion. Run those three items down in PTAB E2E before relying on them in a brief.

I'll start by gathering the assignment-record and litigation evidence rather than relying on the Google Patents legal-events excerpt alone.

Useful context. Now let me pin down the litigation and corporate-chain facts.

Ownership Reconstruction — US 11,298,320 B2 ("Liposomal apparatus and manufacturing methods")

Method note / limitation up front: I could not retrieve USPTO Assignment Center reel/frame numbers in this session — neither Google Patents' legal-events pane on the patent page nor the indexed litigation/SEC sources expose them. Rather than guess, every reel/frame field below is marked not retrieved, and the recorded dates/conveyances that are documented are cited to source. Verify the reel/frame against the Assignment Center entry for patent number 11298320 before relying on this for diligence: https://assignmentcenter.uspto.gov/ (mirror: https://assignment.uspto.gov/patent/index.html).

Inventors

Pattern notes:

• No "inventor exodus" signal. There is no evidence any of the four departed the original assignee within 12 months of the 2002-06-28 priority date. The opposite: the same inventors recur across the family and are still publicly credited by Arbutus in 2026 — Arbutus's CEO's March 3, 2026 statement names "Ian MacLachlan, Ed Yaworski, Lloyd Jeffs, Kieu Lam, Lorne Palmer" as the inventors whose work enabled the vaccine (https://www.theglobeandmail.com/investing/markets/stocks/ABUS/pressreleases/36523222/). MacLachlan in particular is named on 51 patents attributed to Protiva Biotherapeutics (https://www.patentleaderboard.com/protiva-biotherapeutics/ian-maclachlan/[490972](/patent/490972)). This is a career-tenure pattern, not a fire-sale pattern.
• Record discrepancy worth resolving (not a fraud finding). The 2021-05-25 recorded assignment of inventors' rights lists assignors "GIESBRECHT, NOELLE, JEFFS, LLOYD, MACLACHLAN, IAN, PALMER, LORNE R." (per the Google Patents legal-events record). The issued patent names Cory Giesbrecht. A differing first name on an inventor-assignment record usually indicates a legal representative/executor signing for a deceased or incapacitated inventor, or a recording error. I flag it as literally recorded; I did not find evidence either way.

Original assignee

Protiva Biotherapeutics, Inc. — a British Columbia, Canada corporation, and a wholly-owned subsidiary of Tekmira Pharmaceuticals Corporation. Protiva was the applicant on the 2003 parent application (U.S. Ser. No. 10/611,274, which issued as US 7,901,708 on 2011-03-08, per the cross-reference paragraph on the '320 face). Google Patents displays "Original Assignee: Arbutus Biopharma Corp" for this record, but that field reflects the current owner; the operational first-party for the 2002/2003 invention was Protiva, corroborated by the recorded inventor assignment naming Protiva as assignee and by the PTAB's own recitation in IPR2018-00739.

• Primary line of business: LNP/nucleic-acid-lipid-particle formulation and manufacturing R&D. The '320 claims an apparatus (reservoirs, pump mechanism, mixing chamber with opposing ~180° flows) for producing lipid vesicles — a manufacturing platform, not a marketed drug. The platform is embodied in LNP products made by licensees; Alnylam's Onpattro (RNAi, FDA-approved August 2018) was developed "under an LNP license from Arbutus" (D. Del. C.A. 22-252 complaint). I have not verified that Onpattro's manufacture literally practices the claimed apparatus.
• Current status: Protiva no longer exists as a separate entity. Per the Patent Owner's real-party-in-interest statement in an Arbutus PTAB proceeding: "Protiva Biotherapeutics, Inc. existed as a wholly-owned subsidiary of Arbutus Biopharma Corporation. Protiva Biotherapeutics, Inc. was amalgamated into Arbutus Biopharma Corporation in January 2018" (https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1508276](/patent/1508276)/download-documents). Arbutus Biopharma Corporation (Nasdaq: ABUS) is today an operating, solvent, clinical-stage biopharmaceutical company (Warminster, PA) — as of July 16, 2026 it announced receipt of ~$178M from Moderna and an intent to return up to ~$230M of capital (https://investor.arbutusbio.com/node/19581/pdf). No bankruptcy, no dissolution.

Assignment timeline

The patent's own legal-events record shows exactly two recorded assignments, both with recordation date 2021-05-25 — the same day application 17/330,209 was filed. That co-dating indicates the chain was re-papered onto the new continuation at filing, not in response to any litigation or liquidity event.

• 2003 (execution date not retrieved — presumably on/around the 2003-06-30 parent filing) / recorded 2021-05-25 — Reel not retrieved

  • Conveyance: Assignment (inventors → company)
  • Assignor: Giesbrecht, Noelle; Jeffs, Lloyd; MacLachlan, Ian; Palmer, Lorne R. (as recorded)
  • Assignee: PROTIVA BIOTHERAPEUTICS, INC.
  • Correspondent: not retrieved — the correspondent field is not exposed in the sources available to me; no recurrence analysis is possible
  • Context: original inventor assignment to the founding employer — first link of the chain

• 2018-01-01 (merger effective date, per PTAB record) / recorded 2021-05-25 — Reel not retrieved

  • Conveyance: Merger (amalgamation)
  • Assignor: PROTIVA BIOTHERAPEUTICS INC.
  • Assignee: ARBUTUS BIOPHARMA CORPORATION
  • Correspondent: not retrieved
  • Context: internal corporate reorganization — subsidiary folded into the parent; no change in ultimate beneficial ownership

No assignments recorded after 2021-05-25. That is itself the key finding: Arbutus Biopharma Corp. is still the record owner. Genevant Sciences GmbH's interest is an exclusive license under a cross-license agreement (with a right to sue), not a recorded assignment — the D. Del. complaint pleads that the patents are "assigned to and owned by Arbutus" while "Genevant has held Exclusive Rights."

Chain-of-title gap to note for diligence: the corporate lineage Inex Pharmaceuticals → Tekmira Pharmaceuticals → renamed Arbutus Biopharma (2015) is documented in SEC filings (Arbutus 10-Q, "Arbutus Biopharma Corporation (formerly Tekmira Pharmaceuticals Corporation)") and in the PTAB's RPI statement ("Arbutus Biopharma Corporation (fka 'Tekmira')"), but no Change-of-Name assignment appears in this patent's recorded events. That is unremarkable for a name change, but it means the record chain as recorded consists of only the two links above.

Timeline diagram

timeline
    title Ownership of US 11298320
    2002 : Priority date 28 June 2002
    2003 : Parent application filed by Protiva
    2011 : Parent patent 7901708 issues
    2015 : Tekmira renamed Arbutus Biopharma
    2018 : Protiva amalgamated into Arbutus
    2021 : Continuation 17330209 filed 25 May
         : Inventor assignment to Protiva recorded
         : Protiva merger into Arbutus recorded
    2022 : Patent 11298320 issues 12 April
    2023 : Pfizer and BioNTech suit filed naming the 320 patent
         : Patent term ends 30 June 2023
    2026 : Moderna pays 950M under global settlement

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only two recorded conveyances are an inventor assignment and an intra-group merger; the assignee on both is the originating operating company (Protiva) and its public parent (Arbutus, Nasdaq: ABUS). No "IP / Licensing / Holdings / Ventures" assignee appears, no registered-agent address appears, and the record contains no single-purpose LLC.
2. Known asserter in the chain — not present. None of Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp or Spangenberg entities appears as assignee. The current owner is a clinical-stage pharmaceutical company; the exclusive licensee, Genevant Sciences GmbH, is a subsidiary of publicly traded Roivant Sciences Ltd. (Nasdaq: ROIV), which holds 83% of Genevant's parent (Arbutus 16%). Note the monetization flavor but also the substance: the operating originator retains title and takes 20% of recovery, Genevant 80%.
3. Repeat correspondent across the chain — unclear (no data). Correspondent/recording-attorney fields were not retrievable in this session, so I cannot test recurrence, and I will not infer it from firm names appearing elsewhere (Kilpatrick prosecuted these patents but prosecution counsel is not the same as assignment correspondent).
4. Cascading transfers — not present. Two records, one of which is a merger, both recorded on 2021-05-25; no chained LLCs, no <24-month cascade.
5. Pre-litigation transfer — not present. The last recorded transfer (2021-05-25) predates the first suit naming the '320 patent — Arbutus/Genevant v. Pfizer and BioNTech, filed 2023-04-04 in D.N.J. — by ~22 months, and predates Acuitas's D.N.J. declaratory-judgment action (3:23-cv-04200, filed 2023-08-04) by ~26 months. The merger link precedes the suits by ~5 years.
6. Bankruptcy fire-sale — not present. No Chapter 7/11 for Protiva or Arbutus; Arbutus is paying dividends/buybacks in 2026.
7. Privateering — unclear / partially present in structure, not in title. Arbutus granted an exclusive license (including standing to sue) to Genevant, an entity 83% held by Roivant, and the two co-plaintiff every COVID-vaccine case. That is a licensing-monetization overlay. It does not satisfy the classic privateering definition here because title never moved and the originator shares in the recovery; characterize it as an exclusive-license enforcement vehicle, not a transfer to an unaffiliated NPE.
8. Defensive aggregator (anti-NPE) — not present. Nothing in the record points to RPX, AST, LOT, Unified or OIN.

Additional finding outside the eight signals: the patent's term is expired as of 2023-06-30 (20 years from the 2003-06-30 parent filing; Google Patents status "Expired – Lifetime," anticipated expiration 2023-06-30). It issued 2022-04-12, giving roughly 14 months of enforceable life, and the suits against Pfizer/BioNTech and Acuitas were filed in that window. The $2.25B Moderna outcome (settlement announced 2026-03-03) resolved on different patents in the portfolio (the '069/'359/'668/'435/'651/'378 formulation family), not on the '320.

Verdict

Operating-company assertion.

Title never left the originating corporate family: the only recorded conveyances are (i) the inventors' assignment to Protiva Biotherapeutics, Inc. and (ii) the merger of Protiva into Arbutus Biopharma Corporation, both recorded 2021-05-25 (the day continuation 17/330,209 was filed), so current record ownership sits with a solvent, Nasdaq-listed operating pharmaceutical company that itself uses and licenses the patented LNP manufacturing technology. The enforcement history fits an operating-company-vs-competitor posture — suit filed against Pfizer/BioNTech on 2023-04-04 in D.N.J. naming the '320 patent, and against Moderna on 2022-02-28 in D. Del. — with none of the shell-entity, known-asserter, cascading-transfer, pre-litigation-transfer or bankruptcy markers present. The one caveat is the Genevant/Roivant exclusive-license enforcement vehicle, which I treat as a monetization overlay rather than a transfer to an NPE, since Arbutus retained title and 20% of the recovery.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 11298320) — reel/frame and correspondent confirmation is the one remaining gap in the above.

I'll search for this specific patent and its cited references.

Let me pull the actual citation record from the patent's front page.

Let me retrieve the complete front-page reference list from the patent PDF.

Scope note before the analysis

I was unable to reach USPTO PatentCenter / Patent Public Search directly in this session; the front-page "(56) References Cited" data below was retrieved from open-web copies of the printed patent (the Google Patents PDF image and the D.N.J. complaint-exhibit PDF of the same document, gov.uscourts.njd.510682.1.5.pdf). Two consequences you should weigh:

1. My retrieval of the (56) list is truncated, not complete. The U.S. patent list was cut off after 5,736,392 A 4/1998, and the foreign-document list was cut off at WO 2001/05373 A1. Do not treat the list below as the whole citation record — only as the portion I could actually read.
2. gov.uscourts.njd.510682.1.5.pdf carries the same title ("Liposomal Apparatus and Manufacturing Methods") and the same §CROSS-REFERENCE paragraph as the '320, but so does US 11,318,098 (issued 2022‑05‑03), which is the sibling filed as Ser. No. 17/329,755. I cannot confirm that the exhibit is the '320 rather than the '098. Their front-page (56) lists are near-identical in any event.

Also flagging a conflict with the earlier-generated section: my prior summary could not retrieve the claim set and warned that the patent's claims are apparatus claims (1 and 18). Where the anticipation mapping below turns on claim elements, I am relying on litigation-transcribed claim language, not the printed claim column. Where a reference is mapped, treat it as a candidate mapping, not a concluded anticipation.

A. Face-of-patent references as literally retrieved

A.1 U.S. Patent Documents

Reported verbatim as the two OCR renderings gave them. Where the two renderings disagree I give both and correct nothing (per the literal-interpretation rule) — these are almost certainly OCR variants of one printed list.

* The 5,705,385 entry carries an asterisk and the trailing classification A61K 9/1272 / 264/4.1 — the asterisk convention on U.S. front pages marks a reference the examiner/applicant treated as of particular interest. A61K 9/1272 is the CPC subclass for liposome preparation processes and 264/4.1 is a micro-encapsulation class — i.e., this is a process/apparatus reference, which makes it markedly more on-point to the '320's subject matter than the cationic-lipid transfection references around it.

A.2 Foreign Patent Documents

A.3 Other Publications

• Arpicoo, S. et al., "Preparation and characterization of novel cationic lipids developed for gene transfection," Proceed. Int'l Symp. Control. Rel. Bioact. Mater. (Controlled Release Society, Inc.), 1999, 26:759–760.
• Hirota, S. et al., "Simple mixing device to reproducibly prepare cationic lipid‑DNA complexes (lipoplexes)," BioTechniques, 1999, 27(2), 286–290. — printed with a trailing asterisk and "(Year: 1999)", which is the U.S. front-page convention for a reference considered important to patentability.

A.4 References cited in the specification body (also in the §BACKGROUND)

• U.S. Pat. No. 5,478,860 — Wheeler et al., issued Dec. 26, 1995 — "microemulsion compositions for the delivery of hydrophobic compounds." Expressly stated to be incorporated herein by reference. (This is the only cited reference whose date and disclosure the authoritative patent text confirms from within itself.)
• PCT Publication WO 01/05373 — Knopov et al. — "techniques for preparing lipid vesicles using an ethanol injection-type process with a static mixer that provides a turbulent environment (e.g., Reynolds numbers >2000)," with therapeutic agents loaded after vesicle formation.

B. A threshold issue that governs the whole §102 analysis

The mapping of any reference to claims 1 and 18 depends entirely on the effective filing date of those claims — and that date is contested.

• If claims 1 and 18 are entitled to the listed 2002‑06‑28 priority date, then only art published before mid‑2002 is §102 art, and every reference on the (56) list qualifies (all are ≤ 2001).
• If they are not so entitled — and per the earlier section, Pfizer/BioNTech's counterclaims allege that the "different flow rates relative to each other" limitation was first introduced in the 2021 continuation and that the earlier family members ('708, '070, '386) all claimed "about equal flow rates" — then a much larger body of 2002–2021 art becomes available. That is a §112 written-description/enablement argument, but it directly re-scopes the §102 window.

I express no view on which date controls. But no serious anticipation analysis of this number can be done without resolving it, and any prior-art search you commission should be run twice — once bounded at 2002‑06‑28 and once bounded at 2021‑05‑25.

C. Anticipation analysis — reference by reference

Method. §102 anticipation requires a single reference disclosing every element as arranged in the claim. From the (litigation-transcribed) claim language summarized earlier, claims 1 and 18 each require, in substance:

The controlling structural fact: the '320's independent claims are apparatus claims. The overwhelming majority of the (56) list is composition/transfection/chemistry art (cationic lipids, PEG-lipids, lipoplex formulation). Those references cannot anticipate an apparatus claim as a matter of law — they disclose no reservoirs, no pump mechanism, no mixing chamber, and no flow-rate relationship. For those references the honest characterization is §103 art (or art cited against sibling composition patents), not §102 art against the '320 apparatus claims. I say this plainly rather than manufacturing element-by-element mappings that the references cannot support.

Tier 1 — genuine apparatus/process candidates (the only serious §102 targets)

1. WO 2001/05373 A1 — Knopov et al. (front-page date truncated in my retrieval; the WO year code indicates 2001 publication).

• Description (per the '320's own characterization): ethanol-injection-type process for preparing lipid vesicles using a static mixer producing turbulent flow (Re > 2000); therapeutic agent loaded after vesicle formation.
• Potential §102 relevance: This is the reference the '320 sets itself against, and it is the closest prior art on the list for elements (a)–(c) and (e). It potentially reaches claims 1 and 18 if and only if the reference itself discloses (i) two reservoirs feeding a single mixing junction, (ii) a pump arrangement producing different flow rates as between the streams, and (iii) a T-junction / opposed-flow geometry. My retrieval does not show those disclosures, and the '320's stated point of novelty is that its mixer is non-turbulent (Re < 2000) — which is the inverse of Knopov. Likely outcome: §103, not §102.
• Claims potentially anticipated: 1 and 18 (provisional; contingent on the reference's own disclosure).

2. US 5,705,385 A — Bally (1/1998), asterisked, CPC A61K 9/1272 / 264/4.1.

• Description: The classification data on the face (A61K 9/1272 = liposome preparation processes; 264/4.1 = micro-encapsulation) identifies this as a vesicle-preparation process/apparatus reference, not a lipid-chemistry reference.
• Potential §102 relevance: Because it sits in the same technical class as the '320's apparatus, this is — in my assessment — the single most under-examined entry on the (56) list for claims 1 and 18. Whether it anticipates turns on whether it discloses nucleic-acid-containing aqueous feed, alkanol-solubilized lipid feed, differential flow rates, and a 180°/90–180° opposed-flow junction. I do not have the reference's text and cannot confirm.
• Claims potentially anticipated: 1 and 18 (unverified).

3. Hirota, S. et al., BioTechniques 1999, 27(2):286–290 — asterisked "(Year: 1999)".

• Description: titled "Simple mixing device to reproducibly prepare cationic lipid‑DNA complexes (lipoplexes)."
• Potential §102 relevance: This is the only non-patent reference on the face of the patent directed to a mixing device for lipid–DNA complex formation. Element (d) is the crux: a "simple mixing device" may or may not be a T-junction with opposed flows at ~180°. It plainly speaks to elements (a)–(c) and (e).
• Claims potentially anticipated: 18 (the broader 90°–180° geometry claim) is the more plausible target; claim 1 (about 180°) requires closer geometry. (Unverified — I have not read the paper.)

Tier 2 — liposome preparation/encapsulation process art

4. US 5,478,860 — Wheeler et al., Dec. 26, 1995 (confirmed from the '320's own §BACKGROUND; expressly incorporated by reference).

• Description: microemulsion compositions for delivery of hydrophobic compounds; in vitro and in vivo delivery methods.
• Potential §102 relevance: Discloses compositions and delivery, and per the '320's own summary is not directed to a two-reservoir/differential-flow mixing apparatus. It is the classic §103 primary reference against composition/process claims in this family, but it does not anticipate apparatus claims 1 or 18.
• Claims potentially anticipated: none, as to claims 1/18; potentially relevant to any process claims in the set (claim set unconfirmed).

5. US 4,394,448 — Szoka, Jr. et al. (7/1983).

• Description (from my background knowledge, not from the retrieved record): reverse-phase-evaporation liposome preparation. Flagged as unverified — I did not retrieve the reference text or title in this session.
• Potential §102 relevance: Process art. No disclosed two-reservoir differential-flow mixer. §103 candidate at most.
• Claims potentially anticipated: none as to 1/18.

6. US 4,515,736 — Deamer (5/1985). Liposome-preparation art. Same reasoning as (5). §103 candidate.

7. US 5,225,212 — Martin et al. (7/1993). Liposome art. §103 candidate.

8. US 5,171,678 — Behr et al. (12/1992); US 5,264,618 — Felgner et al. (11/1993); US 5,703,055 — Felgner et al. (12/1997). Cationic-lipid / transfection art. These are the references that populate the Background's "cationic lipid" discussion (DODAC, DOTMA, DDAB, DOTAP, DC-Chol, DMRIE). They cannot anticipate an apparatus claim. §103 and/or §112-support art only.

9. US 5,279,833 (Rose, 1/1994); US 5,283,185 (Epand et al., 2/1994); US 5,230,906/5,320,906 (Eley et al., 6/1994); US 5,334,761 (Gebeyehu et al., 8/1994); US 5,424,073 (Rahman et al., 6/1995). Liposome/transfection adjunct art (targeting, PEGylation, transfection reagents). §103 candidates against composition claims; not §102 art against 1/18.

10. US 4,897,355 (Eppstein et al., 1/1990); US 5,208,946/5,208,036 (Eppstein et al., 5/1993); US 5,545,412 (Eppstein et al., 8/1996); US 5,013,556 (Woodle/Woodie et al., 5/1991); US 5,578,475 (Jessee, 11/1996); US 5,552,157 (Yagi et al., 9/1996); US 5,593,622 (Yoshioka et al., 1/1997); US 5,627,159 (Shih et al., 5/1997); US 5,641,662 (Debs et al., 6/1997); US 5,653,996 (Hsu, 8/1997); US 5,656,743 (Busch et al., 8/1997); US 5,674,908 (Haes et al., 10/1997); US 4,687,661 (Kikuchi et al., 8/1987); US 4,394,372 (Taylor, 7/1983). Bulk liposome/transfection/detergent–dialysis art. None discloses the claimed apparatus. §103 only.

Tier 3 — Foreign documents A.2

The WO/CA entries (WO 98/51278, WO 98/51285, WO 98/58630, WO 99/14346, WO 2000/00178, WO 2000/03683, WO 2000/15820, WO 2000/029103, WO 2000/62813, CA 2041075, CA 2309727) are, on their face, lipid-nucleic-acid particle and formulation art of the same character as Tier 2 — cited against the composition lineage, not the apparatus. WO 2000/62813 A2 recurs in the D. Del. claim-construction record for this family (it appears in Arbutus's intrinsic-evidence lists alongside WO 98/051278 and WO 00/003683), which suggests it is a formulation/process reference rather than an apparatus one. I did not retrieve these documents' texts and cannot map them to claims 1/18. Treat them as §103 candidates pending review.

A note on the trailing asterisk entries

On a U.S. front page, an asterisk next to a reference conventionally means the reference was cited during prosecution and considered by the examiner. Two entries carry that mark: US 5,705,385 (Bally) and Hirota et al. (1999). Those two, plus WO 01/05373 (Knopov) and US 5,478,860 (Wheeler) — the two references the specification itself addresses — are the four references that actually matter for a validity challenge to the '320. Everything else on the list is inherited citation baggage carried forward from the 2003-era '708 prosecution.

D. What this means practically

1. There is no reference on the face of the '320 that, on the record I retrieved, anticipates claims 1 or 18. The claims are apparatus claims requiring a two-reservoir, differential-flow, opposed-flow mixing geometry; the (56) list is dominated by lipid-composition art that discloses no such structure.
2. The four references worth briefing are, in priority order: WO 2001/05373 (Knopov) → US 5,705,385 (Bally) → Hirota et al., BioTechniques 27(2):286–290 (1999) → US 5,478,860 (Wheeler). The best §102 theory is Knopov or Bally against claim 18 (the broader 90°–180° geometry); the best §103 theory is Knopov in view of Hirota or Bally.
3. The real vulnerability is not the (56) list — it is the priority question. If the "different flow rates relative to each other" limitation cannot claim 2002‑06‑28, then the search space for §102 art expands from "pre-2002" to "pre-2021," which brings in the entire 2003–2021 lipid-nanoparticle literature (including the family's own intervening publications, e.g. MacLachlan WO 2005/007196 and US 2006/0134189 A1 — the very references that Pfizer/BioNTech/Moderna plead against the sibling patents).

E. Explicit uncertainties

1. The (56) list I retrieved is incomplete — truncated after 5,736,392 A (U.S.), after WO 2001/05373 A1 (foreign), and after the Arpicoo and Hirota entries (other publications). There are almost certainly more references on the printed face of the patent that I did not see. Do not rely on absence.
2. The exhibit from which I took the foreign-document list may be the '098 patent, not the '320. Same title, same cross-reference chain; not disambiguated.
3. Several printed numbers differ between my two OCR sources (4,488,052/4,438,052; 4,598,961/4,598,051; 5,208,946/5,208,036; 5,230,906/5,320,906; "Woodie"/"Woodle"; "Feigner"/"Felgner"). Per the literal-interpretation rule I have reported both and corrected neither.
4. Titles, filing dates, and disclosures for individual references were not retrieved. The task asked for publication/filing dates; I could supply only the dates printed on the '320's face (which for U.S. patents are issue dates, not filing dates). Any element-by-element §102 mapping must be re-run against the actual reference documents.
5. The claim set is unconfirmed (see the earlier section). The mapping above assumes independent claims 1 and 18 as characterized in the litigation papers, with claim 1 at "about 180°" and claim 18 at "90°–180°," and does not account for dependent claims or any process claims that may exist.
6. "Cited by" / forward citations (e.g., US 11,298,320 appearing as a citation in later Arbutus filings) are not prior art to the '320 and are excluded from this analysis.
7. No assumption is made about the assignee, the litigation posture, or the September 2025 claim-construction ruling's effect on these mappings — a construction of "mixing chamber," "different flow rates," or "instantaneously" would materially re-scope every §102 theory above.

I'll research the prior art references relevant to this patent's claims, particularly the references cited in the patent itself and any references from the related litigation.

I have strong leads. Let me pin down the secondary references' identities/dates and check for any invalidity contentions specifically targeting the '320 patent.

Obviousness Analysis — US 11,298,320 B2 under 35 U.S.C. § 103

Analyst note on scope and sourcing. I was able to retrieve and read the substantive text of the principal prior-art references during this session (WO 01/05373 via the AU771706B2 family copy; US 5,478,860; the Optime "Liposome Production" applications). I could not retrieve the printed claim column of the '320 patent itself, so — as flagged in the prior sections — the claim language I chart against is the litigation-transcribed text (claims 1 and 18, apparatus). Courts construe claims as a matter of law; the mapping below is an invalidity hypothesis keyed to that transcribed language, not a merits opinion. Where a reference's own date is uncertain, I say so rather than assume.

1. Threshold issue that controls everything: the effective filing date

Because the '320 patent claims priority through to Provisional 60/392,887 (June 28, 2002), the pre-AIA §§ 102/103 regime applies if, and only to the extent that, the challenged claims are entitled to that date.

This matters enormously here, for the reason the prior section already identified: the prior-family patents ('708/'070/'386) claimed mixing at "substantially equal flow rates," whereas '320 claim 1 recites pumping the two streams "at different flow rates relative to each other." I found independent corroboration of this in the European family members retrieved this session:

• EP 1 519 714 B1 (EP counterpart of the '708) — claim 35: a pump mechanism configured to pump the aqueous and organic lipid solutions "à des débits pratiquement identiques" (substantially identical/equal flow rates), with the T‑connector and opposing flows at ~180°, and claim 41 reciting continuous stepwise dilution.
• EP 2 823 809 B1 (a later-divided member of the same family, pub. Jan. 14, 2015) — recites lipids solubilized in a lower alkanol at "70% v/v to 100% v/v" at "substantially equal flow rates," again with the T‑connector/180° limitation.

Two consequences:

1. Priority risk for the patentee. If "different flow rates" is not supported by the June 28, 2002 provisional (and the equal‑flow-rate claims in the family suggest it may not have been), the claim's effective date could move to a much later date — in which all of the references below, including the Optime filings, become § 102 prior art. This is precisely the kind of "priority is a § 103 predicate" issue that should be resolved before any obviousness argument is credited or rejected.
2. A flag against the prior section. The prior section reported claim 1's alkanol limitation as "about 75% v/v to 100% v/v." Family member EP 2 823 809 B1 states "70% v/v to 100% v/v." These are reconcilable within "about," but the discrepancy should be checked against the certified claim copy before reliance. I could not resolve it from the sources available.

POSA definition used: a person with a B.S./M.S. in chemical engineering, pharmaceutics or a related discipline and 2–5 years' experience formulating lipid vesicles/lipid-nucleic-acid particles, familiar with ethanol-injection and continuous in-line mixing.

2. The claim elements to be met

3. The prior-art references

3.1 Primary art (unambiguously prior art — published/issued >1 year before June 28, 2002)

R1 — WO 01/05373 A1 (Knopov, Dzubanov, Harper & Cullis; Inex Pharmaceuticals Corp.), "Methods and Apparatus for Preparation of Lipid Vesicles," published Jan. 24, 2001 (PCT/CA00/00842; priority July 14, 1999).
Verified from the AU771706B2 family copy. Discloses:

• An apparatus comprising "(a) a first reservoir for receiving a buffer composition; … (c) a second reservoir for receiving a lipid solution; (d) a dispensing head … (e) a connector joining the second reservoir to the dispensing head … wherein the dispensing head has formed therein one or more injection ports having a diameter of 2 mm or less." → meets element A/B architecture and provides a mixing aperture.
• A third aspect reciting "a first feeder tank containing an ethanolic lipid; a second feeder tank containing an aqueous buffer; (c) a combining chamber disposed to receive…" → a two-reservoir, pump-fed, chamber-mixing apparatus.
• "a solution of ethanolic lipid comprising from about 1 to about 100 mg/ml lipid in at least 90% by weight ethanol" (claim 1/2; claim 2 also recites the first reservoir containing citrate buffer) → squarely within element B ("75–100% v/v").
• "injecting the ethanolic lipid directly into aqueous buffer through an injection port… to make a lipid/buffer mixture" → element E's dilution-by-mixing.
• Resulting vesicles "in about 10% or more by weight ethanol, and have average diameter of from about 80 nm to about 200 nm" without an extrusion step → the same small-vesicle, no-post-sizing result the '320 touts.
• "Therapeutic agents may then be loaded after vesicle formation" (as characterized in the '320 background) → element A's therapeutic payload.

R2 — U.S. Pat. No. 5,478,860 (Wheeler et al.; Inex Pharmaceuticals Corp.), issued Dec. 26, 1995. Microemulsions for hydrophobic-compound delivery, PEG-linked lipids, and a polar-lipid monolayer surrounding an oil core (verified). Cited in the '320 background itself. Supplies the lipid-formulation element (PEG-lipid, delivery of a therapeutic compound) and, as an Inex reference, the same corporate/technical lineage.

3.2 Secondary art (qualification depends on the priority issue in § 1)

R3 — US 2003/0124033 A1 (Baker & Heriot; OPTIME Therapeutics), "Method and apparatus for liposome production," filed Nov. 15, 2002, published July 3, 2003 (granted as US 6,855,277). Verified content:

• Two temperature-controlled phase reservoirs; first and second "precise metering" pumps with manifolds → element C (a pump mechanism with independently set rates).
• A pre-mixing system with first and second inlet orifices and, in FIG. 11, a T-shaped section in which "the injector section … extends within the T portion of section 434 and exits directly into the pre-mixing chamber" → element D (T-geometry, two streams meeting at an aperture).
• "The ratio of (a) the internal cross-sectional area of the branched portion … to (b) the internal cross-sectional area of injector section 446 is determined by the desired volumetric ratio of the aqueous phase to the lipid phase" and claim 45 ("the fluid flow rate of the lipid phase is about 3 to 200 cm³/sec, and the fluid flow rate of the aqueous phase is about 5 to 300 cm³/sec") → element C's "different flow rates" expressly taught.
• "an active agent is encapsulated in either the aqueous core of the lipid vesicles, within the lipid bilayer … or both" → element A's payload-in-aqueous-phase teaching.

R4 — US 2004/0032037 A1 (continuously produced lipid vesicles via a phase-intersection/cross-flow module; published Feb. 19, 2004). Verified content: the polar and lipid-containing phases are "transported separately … and fed to a phase intersection region … preferably in the form of a cross-flow module"; the lipid phase flows into the polar phase "via at least one laterally arranged orifice"; the liquid is deliberately not stirred ("neither stirred nor is a homogenizer or another mechanical stirring or dispersing aid used"); and "by regulating the feed rates and flow rates of both the polar and the lipid-containing phases and by varying the metering pressure … the self-assembly process … is controllable." → corroborates elements C and E, and the low-shear/non-turbulent theme.

R5 — US 2003/0077829 A1 (MacLachlan), published April 2003. Listed in the "References Cited" section reproduced on a family counterpart of the '320. I could not retrieve its content this session; flagged for completion.

Date qualification (critical for R3–R5): Each of R3–R5 published in 2003–2004, after June 28, 2002. They are not § 102(a)/(b) art for a claim entitled to the 2002 priority date. R3 (US filing Nov. 15, 2002) would qualify, if at all, only under § 102(e) — and only if the '320 claim is not entitled to June 28, 2002. Their prior-art status therefore rises and falls with the priority question in § 1. R1 and R2 are not subject to this caveat.

3.3 Background/acknowledged art

The '320 background itself acknowledges as known: sonication, detergent dialysis, ethanol injection or dilution, French press extrusion, ether infusion, reverse-phase evaporation, and "conventional ethanol dilution, [which] involves the injection or dropwise addition of lipid in an aqueous buffer." The classical ethanol-injection literature (e.g., Batzri & Korn, Biochim. Biophys. Acta 298:1015 (1973)) and post-formation nucleic-acid-lipid-particle work in the inventors' own corporate lineage (e.g., the "SPLP" literature of the late 1990s) are the natural background; I did not fetch them this session, so I cite them only as acknowledged art, not as independently verified references.

4. The core combination: R1 (Knopov) primary + R3 (Baker/Optime) + R4

4.1 Element mapping

4.2 Why a POSA would combine them

1. Same field, same problem, same solution architecture. R1 and R3 are both liposome-manufacturing apparatus/method references aimed at the identical problem the '320 recites in its own background: scalable continuous production of small, homogeneous vesicles with high encapsulation, avoiding post-hydration extrusion. Both disclose two reservoirs feeding a mixing region via pumps/metering systems. Combination is the textbook "same field of endeavor / reasonably pertinent" case.

2. The '320 background supplies the express motivation to modify R1. The '320 specification criticizes R1's approach ("the process does not involve a static mixer or specialized extrusion equipment"). A POSA wishing to simplify Knopov's static-mixer/turbulent design would naturally replace the static mixer with the simplest known in-line combining element — a T-connector — which R3 discloses and which is a notoriously well-known fluid-handling component. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (known element, known function, predictable result = obvious).

3. "Different flow rates" is taught, and in any event is an inevitable design parameter. R3 expressly claims unequal lipid/aqueous rates and ties the rate ratio to the desired volumetric ratio; R4 teaches "regulating the feed rates and flow rates of both." Moreover, a claim to a pump "configured to pump … at different flow rates" reads on any two-pump/two-feeder system with independently settable rates, including R1's two feeder tanks — i.e., the limitation is met by capability, not by operation. That makes element C nearly de minimis over R1 alone.

4. Reasonable expectation of success. Every reference produces 80–200 nm vesicles/lipid particles by ethanol dilution in a continuous stream and reports high loading/encapsulation (R1: 95% vincristine loading, 80–200 nm, no extrusion; R3: "higher encapsulation efficiency than state of the art methods"). Combining them would predictably yield the claimed result.

5. Nucleic-acid payload. Supplying the aqueous phase with a nucleic acid was standard in the field (R3: active agent in the aqueous core; R2 and the acknowledged SPLP art: nucleic-acid-lipid particles). A POSA would place the nucleic acid in the aqueous reservoir as a matter of routine choice, with a reasonable expectation of passive entrapment on vesicle formation.

4.3 KSR-style rationales available

• Known technique / predictable variation: replacing a static mixer with a T-connector; setting two pumps to unequal rates.
• Design choice: mixing-angle selection within 90°–180° (claim 18) is a routine geometric choice; the '320 itself asserts vesicles "<100 nm" can be formed across 27°–180°.
• Obvious to try: a finite, small set of known in-line mixer geometries (T, Y, cross-flow) with predictable results.

5. Claim 18 and the dependent claims

• Claim 18 differs only in the introduction angle ("between 90° and 180°"). R3's T-shaped injector-in-a-T and R4's laterally arranged orifice both fall within this range, so claim 18 is at least as vulnerable as claim 1. The broader angular range also removes any residual argument that the about-180° requirement was non-obvious.
• Dependent claims (2–17, 19+): I could not retrieve their text (consistent with prior-section uncertainty #1). Any that add conventional features — peristaltic pumps, T-connector with hose barbs, citrate buffer, DSPC/Chol/PEG-DSG/DODMA ratios, 20 mM lipid, tangential-flow ultrafiltration/diafiltration — are disclosed or suggested by R1, R2 and the '320's own acknowledged art, and would be obvious as additional design choices. Dependents cannot be charted without the printed claim column.

6. Secondary considerations (to be tested by the patentee)

1. Unexpected results? Weak. R1 already achieves 80–200 nm vesicles with no extrusion and high loading, so the '320's "no post-sizing" and "up to ~90%" results are not unexpected over R1. The '320 claims to an apparatus, not to the SPLP formulation, so formulation-level efficacy data (e.g., mRNA-LNP performance) is of attenuated relevance to these claims.
2. Long-felt need / commercial success: the COVID-19 LNP vaccines show industry adoption of LNP technology generally, but nexus to the claimed apparatus (as opposed to the formulation patents) would need to be shown.
3. Licensing/industry praise: none retrieved for this number.
4. Copying/failure of others: none retrieved.

None of these, as currently documented, appears to overcome the R1+R3+R4 combination.

7. Conclusion

On the evidence retrieved, claims 1 and 18 (and their dependents) are prima facie obvious under § 103 over WO 01/05373 (Knopov) in view of US 2003/0124033 A1 (Baker, Optime) and US 2004/0032037 A1, further in view of U.S. 5,478,860 (Wheeler) for the lipid/payload elements. WO 01/05373 alone supplies every architectural element at the claimed alkanol concentration and the no-extrusion result; the only meaningful gaps — explicit unequal flow rates and a T-connector — are taught outright by the Optime filings and/or are matters of known, predictable design choice.

The single most important unresolved gating question is priority. If the '320 claims are entitled to June 28, 2002, R3–R5 are disqualified as § 102(a)/(b) art (surviving, if at all, only under § 102(e)), and the obviousness case leans almost entirely on WO 01/05373 + U.S. 5,478,860 + the acknowledged background. If the claims are not entitled to 2002 — a real risk given that the family's own earlier claims recited "substantially equal flow rates" — the full R1+R3+R4 combination is squarely available and the case is very strong.

8. Explicit uncertainties / open items

1. Claim text is litigation-sourced, not read from the printed claims; the dependent claims are uncharted. Verify against the certified copy.
2. Priority support for "different flow rates" in the June 28, 2002 provisional is unverified and is outcome-determinative for the prior-art set.
3. R3/R4/R5 dates: I verified R3's filing (Nov. 15, 2002) and R4/R5 publication dates, but not their earliest priority claims; whether U.S. 6,534,018 (Optime) predates June 2002 is unverified.
4. Unresolved discrepancy flagged against the prior section: claim 1 alkanol range reported as "about 75–100% v/v" (litigation) vs. "70–100% v/v" (EP 2 823 809 B1, same family).
5. Corroboration of the prior section: EP 1 519 714 B1 claim 35 confirms the earlier family claimed "débits pratiquement identiques" (equal flow rates) with the T-connector/180° limitation — supporting the prior section's point that "different flow rates" is a late-arriving limitation, and reinforcing that the mechanism it adds was long known.
6. I did not find any IPR/PTAB proceeding or CAFC 2026 docket specifically naming the '320; nothing this session contradicts the prior section's finding on that point.