US 12071421

I'll search for this specific patent number and check for any 2026 CAFC docket activity.

Let me dig deeper on the claims and any 2026 PTAB/CAFC activity specific to this patent.

Summary — US 12,071,421 B2

Important caveat up front: I was able to confirm the bibliographic record and abstract from multiple independent sources, but the authoritative claim text was not retrieved. The claim summaries below are marked as inference where I could not verify. I also found no CAFC 2026 docket naming this patent, but I did find related 2026 PTAB activity that may or may not involve it — see the uncertainty note at the end.

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1. Bibliographic data

Inventors (8): Luca Fadini (CH), Peter Manini (CH), Claudio Pietra (IT), Claudio Giuliano (IT), Emanuela Lovati (CH), Roberta Cannella (CH), Alessio Venturini (IT), and Valentino J. Stella (US).

Priority chain (per Espacenet): US 61/564,537 (2011-11-29) → US 13/478,361 (2012-05-23) → PCT/US2012/066778 → US 14/360,991 → 15/194,984 → 15/874,325 → 16/228,835 → 16/896,135 (2020-06-08) → 17/699,522 (2022-03-21). This is a long continuation/continuation-in-part chain, per the specification's cross-reference (which states the application "claims priority to U.S. Provisional Application 61/564,537 … and is a continuation in part of U.S. Non-provisional application Ser. No. 13/478,361").

Representative classifications: C07D401/04 (first/inventive), C07F9/6509, C07F9/02, C07D213/89, C07D213/76, C07D213/74; A61K31/675, A61K31/573; A61P1/08, A61P25/22, A61P25/24, A61P13/10.

Assignment history (recorded, per Google Patents): security interest granted to Hamilton SA LLC on 2022-12-30; released 2023-09-20 back to the Helsinn entities. (Listed as recorded assignment data; not a legal conclusion on ownership.)

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2. Abstract (verbatim)

"Disclosed are compounds including phosphate and N-oxide prodrugs of the NK1 antagonist netupitant, useful in the prevention and/or treatment of diseases including emesis induced by chemotherapy. Also disclosed are methods of making a di-tert-butyl (chloromethyl) phosphate useful in the manufacture of such prodrugs by reacting a dialkylphosphate salt with an acid to obtain the corresponding ester of phosphoric acid, reacting the ester with a quaternary ammonium hydroxide base to form a monobasic salt, and reacting the monobasic salt with chloroiodomethane to form the corresponding chloromethyl dialkyl phosphate."

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3. Plain-language overview of the subject matter

Note the internal mismatch worth flagging: the granted title is narrow (a synthesis process), whereas the pre-grant publication was titled "Substituted 4-phenyl-pyridines" and the disclosure is much broader. The specification covers:

• A class of 4-phenyl-pyridine derivatives of formula (I) (and formulas II–VI) that are NK₁ receptor antagonists — defined as phosphate prodrugs and N-oxide derivatives of the NK₁ antagonist netupitant. The specification states a proviso requiring that if a non-pyridine N-oxide is present, the total number of N-oxides must be more than one.
• Eight named compounds GA1–GA8, including GA1 = 4-(5-(2-(3,5-bis(trifluoromethyl)phenyl)-N,2-dimethylpropanamido)-4-(o-tolyl)pyridin-2-yl)-1-methyl-1-((phosphonooxy)methyl)piperazin-1-ium (a phosphonooxymethyl prodrug of netupitant), and GA4–GA8 (various N-oxide forms). The specification calls the chloride hydrochloride HCl salt of GA1 a "particular preferred compound," asserted to be "tremendously resistant to decoupling of the oxo-phosphonomethyl, and reversion of the active moiety to its parent state."
• The synthesis process named in the title: making a chloromethyl dialkyl phosphate (specifically di-tert-butyl (chloromethyl) phosphate) by (i) acidifying a dialkyl phosphate salt to the free phosphoric acid ester, (ii) converting to a quaternary ammonium (monobasic) salt (tetramethylammonium or tetrabutylammonium hydroxide), and (iii) reacting with chloroiodomethane. The specification motivates this as a purity/economy improvement because "the quality of phosphate ester compositions from commercial sources is too low to provide acceptable yields."
• A one-step, acid-free method of functionalizing tertiary amines with chloromethyl dialkyl phosphate esters to make (phosphooxy)methyl prodrugs, stated to avoid the prior art's multi-step route requiring proton scavengers and strong acid deprotection.
• Stabilization insight: formulating the (phosphooxy)methyl prodrug with two equivalents of HCl (a "chloride hydrochloride" double salt), because the prior art's preferred dibasic salts were found unstable and prone to reverting to the parent drug on storage (FIG. 1 plots degradation over days for disodium, lysine, calcium, phosphate, and chloride-hydrochloride salts).
• Pharmaceutical compositions and methods of use for NK₁-mediated conditions — emesis (CINV, RINV, PONV, acute and delayed), bladder dysfunction, depression, and anxiety — including combination regimens with a 5-HT₃ antagonist (palonosetron, ondansetron, granisetron, tropisetron) and dexamethasone, plus rat and dog PK data.

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4. Independent claims — ⚠ inferred, not verified

I could not retrieve the authoritative granted claim set within my search budget, and the patent text supplied to me is truncated before the claims. I will not fabricate claim language. Based on the abstract and specification, the independent claims most likely fall into these groups (this is inference, not a citation to claim text):

1. A process claim for preparing a chloromethyl dialkyl phosphate, having the three steps recited in the abstract: (a) reacting a dialkylphosphate salt with an acid to give the phosphoric acid ester; (b) reacting that ester with a quaternary ammonium hydroxide base to give a monobasic (quaternary ammonium) salt; and (c) reacting the monobasic salt with chloroiodomethane to give the chloromethyl dialkyl phosphate.
2. A process claim for the one-step, acid-free (phosphooxy)methylation of a tertiary amine (e.g., netupitant) using a chloromethyl dialkyl phosphate ester, likely including a deprotection/acid-treatment step.
3. Possibly composition-of-matter claims to formula (I)/(VI) compounds and/or to the named compounds GA1–GA8 (including the chloride hydrochloride salt of GA1), and method-of-treatment claims — these appear throughout the specification but may or may not have survived into the granted claim set.

Confidence that the granted independent claims are process claims (not compound claims): moderately high, given the granted title. Confidence in the exact wording: low. If you need the claim text, pull it directly from USPTO PatentCenter or the granted-PDF at patents.google.com/patent/US12071421B2 (Claims section) — I did not verify it here.

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5. Litigation / docket status for this specific number — ⚠ not confirmed

• No CAFC 2026 docket naming patent 12,071,421 was found. I searched Federal Circuit 2026 summaries and docket aggregators and did not surface an appeal captioned to this patent. Treat "no CAFC appeal for this number" as a negative search result, not a definitive clearance.
• Related 2026 PTAB activity found: IPR2025-00945, -00946, -00947, -00948, and -00949, with Azurity Pharmaceuticals, Inc. v. Helsinn Healthcare S.A. A Feb. 25, 2026 Patent Owner exhibit and a Jan. 13, 2026 deposition transcript reference "four patents at issue" and "five different IPRs." I could not confirm that US 12,071,421 is among those four patents — the caption and materials reference Helsinn netupitant/palonosetron subject matter generally, and I hit my search-step limit before pinning the exact patent numbers. Flagging this as unresolved.
• Google Patents shows a "First worldwide family litigation filed" indicator (Darts-ip family 48094815), indicating known litigation in the family; it does not itself identify a CAFC docket.
• The DrugPatentWatch listing for "NETUPITANT; PALONOSETRON HYDROCHLORIDE" shows earlier district court cases (e.g., Helsinn v. Gland Pharma, D.N.J., 2022), but none I could tie specifically to 12,071,421.

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6. Data-integrity notes

• The patent number and all identifiers above are reported literally as found; nothing was auto-corrected.
• Where search results and the supplied full text overlapped, they agreed (PubChem, Espacenet, PatentGuru, and Google Patents all give the same title, dates, assignee, and abstract), so there is no conflict to resolve.
• The supplied Google Patents text contains an apparent OCR/segmentation artifact: the "Definitions" section is populated with text organized by extracted phrase fragments (e.g., "alkyl," "heterocycloalkyl") rather than full sentences. I treated the body text as authoritative over those fragment headers.
• One substantive internal discrepancy worth noting: the specification's Summary/Detailed Description describes compound claims of formula (I) and the GA1–GA8 compounds, while the granted title focuses only on the synthesis process — a shift from the pre-grant title ("Substituted 4-phenyl-pyridines"). This suggests the granted claims may be narrower (process-focused) than the disclosure, but I did not verify the actual claims.

Bottom line: US 12,071,421 B2 is a Helsinn Healthcare patent, filed 2022-03-21 and issued 2024-08-27, tracing priority to 2011-11-29, titled to a process for making substituted chloromethyl dialkylphosphates (notably di-tert-butyl (chloromethyl) phosphate), within a disclosure that more broadly claims/applies netupitant phosphate and N-oxide prodrugs (GA1–GA8) for NK₁-mediated conditions including chemotherapy-induced nausea and vomiting. I found no CAFC 2026 docket for this patent number, and I could not confirm whether it is one of the four Helsinn patents in the 2026 Azurity IPRs. For claim-level analysis, go to the granted PDF/PatentCenter claims, which I was unable to verify here.

I'll search for litigation involving US patent 12071421.

Let me check patent-specific litigation sources and the Darts-IP family litigation link noted on the patent page.

Let me check the Unified Patents litigation portal and other patent litigation databases directly.

Answer: No litigation naming US 12,071,421 itself was found

I searched patent-litigation sources (Google Patents' family-litigation linkage, CourtListener/RECAP dockets, paragraphfour.com, drugpatentwatch.com litigation listings, and PTAB/P-TACTS filings) for the exact identifier 12071421 / 12,071,421. I could not identify any case in which US Patent No. 12,071,421 has been asserted, challenged, or otherwise named as a patent-in-suit.

Caveat on confidence: I was not able to query PACER or the Darts‑IP database directly (both are paywalled/registration-gated), and my tool access to the Unified Patents litigation portal did not return docket records for this number. So I cannot rule out a very recent or non-indexed filing. But nothing in the public record surfaced for this specific number.

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Important context: the patent's own page flags family litigation

The Google Patents record for US 12,071,421 (https://patents.google.com/patent/US12071421/en) contains a "Family has litigation" flag with a Darts‑IP link (family ID 48094815) reading "First worldwide family litigation filed." That flag attaches to the patent family, not to US 12,071,421 individually. The family priority date is 2011‑11‑29 and the assignee is Helsinn Healthcare SA.

Consistent with the rules, I am reporting this literally: the flag indicates litigation exists somewhere in this family, but the indexed cases I could locate concern other family members, not the '421 patent.

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Litigation involving closely related Helsinn family patents (for context — NOT the '421 patent)

Helsinn Healthcare S.A. v. Gland Pharma Limited

• Court / Jurisdiction: U.S. District Court for the District of New Jersey
• Case No.: 2:22‑cv‑04635 (ZNQ)(LHG)
• Filed: July 18, 2022
• Plaintiff: Helsinn Healthcare S.A.
• Defendant: Gland Pharma Limited
• Patents-in-suit: U.S. 8,426,450; 8,895,586; 9,186,357; 9,403,772; 9,908,907; 10,208,073; 10,624,911; 10,717,721; 10,828,297; 11,312,698 (the '421 patent is not among them)
• Subject: Gland's ANDA No. 217374 for generic fosnetupitant chloride hydrochloride / palonosetron hydrochloride 235 mg/0.25 mg per 20 mL vial
• Outcome/Status: Resolved by Consent Judgment and Dismissal Order; the docket reflects termination on December 23, 2022. Gland admitted the ANDA submission was a technical act of infringement under 35 U.S.C. § 271(e)(2)(A) and did not rebut the statutory presumption of validity.

PTAB proceedings (Azurity Pharmaceuticals, Inc. v. Helsinn Healthcare S.A.) — these target the netupitant/palonosetron method and formulation patents, again not the '421 patent:

• IPR2025‑00945 — U.S. 8,623,826
• IPR2025‑00947 — U.S. 9,186,357
• Additional Azurity petitions filed May 1, 2025 (e.g., against U.S. 10,828,297)

Helsinn Healthcare S.A. v. Teva Pharmaceuticals USA, Inc. (the Supreme Court "on-sale bar" case, 139 S. Ct. 628 (2019)) concerned palonosetron dosing patents (e.g., U.S. 8,598,219) and is unrelated to the '421 patent.

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Why litigation naming the '421 patent is unlikely so far

• US 12,071,421 issued August 27, 2024 (filed March 21, 2022; priority November 29, 2011).
• It is a process/manufacturing patent ("Process for the synthesis of substituted chloromethyl dialkylphosphates") directed to making di‑tert‑butyl (chloromethyl) phosphate intermediates. Process patents of this type are generally not listed in the Orange Book and therefore are not typically asserted in Hatch‑Waxman Paragraph IV litigation, which is limited to patents listed for the referenced NDA.
• The Akynzeo Orange Book listings I found do not include 12,071,421 in connection with NDA No. 210493 (I saw, e.g., 8,426,450; 8,895,586; 10,208,073; 10,717,721; 10,828,297; 11,312,698; 12,208,109; 11,559,523 across the various NDA entries).

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Bottom line

• Litigation naming US 12,071,421: none known.
• Litigation in the same patent family: yes (flagged by the patent record via Darts‑IP family 48094815), most notably Helsinn Healthcare S.A. v. Gland Pharma Limited, D.N.J. No. 2:22‑cv‑04635, filed July 18, 2022, terminated December 23, 2022 by consent judgment — but that case asserted a different set of Helsinn patents (no '421).
• If you need a definitive negative, a PACER docket search and a Darts‑IP/Unified Patents litigation-portal query would be required; I could not run those directly.

If you'd like, I can attempt targeted follow-ups — for example, searching for any post‑August‑2024 Helsinn complaints or any case caption referencing a "chloromethyl dialkylphosphates" process patent.

I'll start by verifying the canonical list and then searching for any AIA trial activity, since the ODP block indicates none on file.

Let me look specifically for any proceeding naming the '421 patent, and check the Helsinn IPR family more broadly.

The Azurity family targets the CINV-method patents, not the '421 patent. Let me verify whether the '421 patent appears anywhere in litigation/PTAB dockets.

Proceedings overview

Total AIA trial proceedings on US 12,071,421: 0. The structured "PTAB proceedings on file" block (USPTO ODP) returns no IPR, PGR, or CBM for this patent, and my independent web checks of PTAB E2E/docket aggregators and the Helsinn–Azurity IPR docket surfaced no petition naming 12,071,421. Breakdown: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution-denied. The bottom line for a defendant: there is no IPR-based invalidation shortcut available, and there is no estoppel on the books you can borrow — but also no adverse claim-level adjudication that narrows the patent for you. You are litigating this patent on a clean slate, and any invalidity theory you want to run is yours alone to fund.

Because the canonical list is empty, the per-proceeding template has no entries. I have not invented any. What follows instead is (a) what I verified about the absence, and (b) the adjacent Helsinn PTAB activity that IS on the public record — clearly labeled as proceedings on other patents, not on 12,071,421, because it is strategically relevant but is not an outcome for this patent.

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No proceedings on US 12,071,421 — verification trail

• Structured source (authoritative): USPTO ODP "PTAB proceedings on file" block supplied in this prompt → zero records. Per my operating rules, this is the canonical list.
• Independent check: Web search for PTAB petitions and docket aggregators citing "12,071,421" returned no petition, institution decision, or FWD. The only hits tying the number to PTAB-adjacent documents were unrelated.
• Timing check: The patent issued 2024-08-27, so the PGR window under 35 U.S.C. § 321(c) (9 months from grant) closed on or about 2025-05-27 with no PGR filed. IPR remains available to any petitioner not time-barred under § 315(b) — none has been filed as of this review.
• Do not confuse this with the Gland ANDA case. In Helsinn Healthcare S.A. v. Gland Pharma Ltd. (D.N.J. No. 2:22-cv-04635 / counterclaim docket at CourtListener 499051), the asserted patents are the '450, '586, '357, '772, '907, '073, '911, '721, '297, and '698 patents. The "'721" in that caption cannot be US 12,071,421, which did not issue until 2024-08-27, whereas Gland's Paragraph IV notice letters are dated 2022-06-02 and 2022-07-11 and the complaint was filed 2022-07-18. Treat any "the '721 patent" reference in the Helsinn Akynzeo docket as a different, earlier-issued patent.

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Context: PTAB activity against sibling Helsinn patents (NOT this patent)

These matter to a defendant only as a pattern signal. None of them adjudicates 12,071,421's claims, and none creates § 315(e)(2) estoppel against anyone as to this patent.

IPR2025-00945 / -00946 / -00947 / -00948 / -00949 — Azurity Pharmaceuticals, Inc. v. Helsinn Healthcare S.A.

• Type: Inter Partes Review (five separate petitions)
• Filed: 2025-05-01 (per Azurity's own related-matters statement in the co-filed petitions)
• Patents challenged (all different from 12,071,421):
  • IPR2025-00945 → US 8,623,826
  • IPR2025-00946 and IPR2025-00947 → US 9,186,357 (split across two petitions by claim set)
  • IPR2025-00948 → US 9,943,515
  • IPR2025-00949 → US 10,828,297
• Status (as retrieved): In IPR2025-00948, the Board granted institution on 2025-11-19 (docket; institution decision PDF via the same docket page). Helsinn had filed a discretionary-denial brief on 2025-08-04; on 2025-09-19 then-Acting Director Stewart denied discretionary denial and referred the petition to the Board. Statuses for -00945, -00946, -00947, and -00949 are not established in the material I retrieved — I will not guess at them.
• Judge panel (IPR2025-00948 institution decision): Administrative Patent Judges Michael J. Fitzpatrick, Sheridan K. Snedden, and Christopher J. Paulraj; opinion authored by Judge Fitzpatrick.
• Petition grounds (representative, from the -00947 petition for US 9,186,357): § 103 obviousness over combinations of Herrstedt, Bös, Herrington, ALOXI label, Hargreaves, and Bonadeo, in eight grounds mapped claim-by-claim (e.g., Ground 1: claims 1, 5–10, 17 over Herrstedt + Bös; Ground 7: claims 21–23, 33–35, 37–39, 43–44, 46–51 over Herrstedt, Bös, Bonadeo, Herrington, and ALOXI).
• Final Written Decision: none reported on this record.
• Settlement / termination: none reported.
• Appeal: none reported.
• Relevance to you (caveated): This shows Helsinn is actively defending an ANDA-driven IPR wave at the Board, and that in at least one 2025 case the Director declined to exercise Fintiv-style discretion in Helsinn's favor. It tells you the Board is willing to institute against this patent family. It tells you nothing about whether 12,071,421's claims are valid.

Bottom-line caveat, stated plainly: the only honest answer to "surfaced every AIA trial proceeding on US 12,071,421" is there are none on file. Everything else is adjacency.

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Strategic summary

Claim status on 12,071,421: 100% UNTESTED. No claim of this patent has been canceled, confirmed, or even challenged at the PTAB. There is no FWD to quote, no claim-level disposition to report, and therefore no "surviving claims" list to give you — the full claim set as granted on 2024-08-27 stands untouched. Anticipated expiration per the structured data is 2032-05-23, which is consistent with the CIP relationship recited in the specification ("continuation in part of U.S. Non-provisional application Ser. No. 13/478,361, filed May 23, 2012") and the 2011-11-29 provisional priority claim. Practically: roughly six years of term remain, which is enough runway to make an invalidity fight worth funding if the patent is asserted against a product you actually sell.

Estoppel landscape: empty. Because no petition was ever filed against this patent, no petitioner and no privy is subject to § 315(e)(2) estoppel as to 12,071,421. Concretely, for a defendant being asserted against today:

• Every § 102/§ 103 ground built on patents and printed publications is available in the IPR forum — nothing has been "used up."
• Equally, you get no free ride: there is no prior FWD invalidating art you could point to, and no petitioner before you whose work product you can adopt.
• Watch the real estoppel risk in the other direction: if you file your own IPR on this patent, you will be estopped in the parallel district court case as to grounds you raised or reasonably could have raised. Given that the '421 specification is a synthesis/method disclosure, the printed-publication art base for a § 103 attack is likely narrower than the system art available in district court (e.g., prior public use, on-sale, § 112 written-description/enablement, inequitable conduct) — so consider whether an IPR is even the right primary vehicle, or whether you keep your best art for court.
• § 315(b) runs one year from service of a complaint alleging infringement of this patent. If Helsinn has not yet served you on the '421 patent, that clock has not started; if it has, it is running.

Pattern signals. Three things stand out.

1. Same petitioner, multiple patents — but not this one. Azurity Pharmaceuticals filed a coordinated five-petition campaign on 2025-05-01 against four Helsinn CINV patents. Azurity is targeting the method-of-treatment and formulation patents that read on generic fosnetupitant/palonosetron. The '421 patent is a process patent in the same commercial ecosystem, and Azurity has conspicuously not challenged it. Either Azurity judged the process claims harder to invalidate, or it judged them unnecessary to clear its ANDA pathway. Both readings are bad news if you were hoping to piggyback.
2. Patent owner litigates hard. Helsinn asserted a ten-patent Akynzeo set against Gland (filed 2022-07-18), asserted the '297 patent against Gland in a separate action, filed a full discretionary-denial brief in IPR2025-00948 rather than conceding, and lost the discretionary-denial fight on 2025-09-19 when the Acting Director referred the petition to the Board. Expect the same posture against you: a contested POPR, a Fintiv-style discretionary-denial brief, and a hard merits defense.
3. No defensive aggregator in the chain. Nothing in the retrieved record shows Unified Patents or any similar entity filing on this family. The petitioners are commercial ANDA filers, not third-party validity challengers — which means a validity challenge against 12,071,421 will only appear if and when a specific competitor needs it.

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Recommended next steps

1. Do not represent, in any demand-letter response or IPR filing, that 12,071,421 has been invalidated or narrowed at the PTAB. It has not. Any statement to the contrary would be false, and there is no FWD to link to.
2. If you are facing assertion on this patent, your invalidity work is ground-up. There is no FWD to cite and no estoppel to inherit. Start from the '421 specification itself: the background section concedes the prior art status of U.S. Pat. No. 5,985,856 (University of Kansas — water-soluble N-phosphoryloxymethyl derivatives of secondary/tertiary amines) and U.S. Pat. No. 6,747,026 (Hoffmann-La Roche — mono-N-oxide 4-phenyl-pyridine derivatives), and the general synthetic-scheme section expressly frames the alleged advance as a "one-step, acid-free synthesis" replacing prior multi-step routes. Those admissions are your obviousness anchor for the process claims, and the file history is where you check whether the § 103 rejection was overcome with argument rather than art.
3. Separate the claim types before you pick a forum. The '421 disclosure spans (i) process claims to making di-tert-butyl (chloromethyl) phosphate — di-tert-butyl phosphate potassium salt + acid, then quaternary ammonium hydroxide base (tetramethylammonium or tetrabutylammonium di-tert-butyl-phosphate), then chloroiodomethane in DME/acetone; and (ii) compound/composition subject matter (formula (I); GA1–GA8, including the chloride hydrochloride salt of GA1 / fosnetupitant). Process claims present § 112 enablement and written-description vulnerabilities that IPR's patents-and-printed-publications-only scope cannot reach — keep those for district court or an ITC defense.
4. Docket-watch IPR2025-00945, -00946, -00947, and -00949. Institution decisions on those petitions (statutory deadline: three months from the POPR, § 314(b)) will tell you whether the Board is receptive to this art family against Helsinn generally. Track them at PTAB E2E and Docket Alarm IPR2025-00948. For the one instituted case (IPR2025-00948), the § 316(a)(11) one-year trial clock runs from the 2025-11-19 institution date, putting the FWD due on or before approximately 2026-11-19.
5. Re-check the ODP block before you rely on "no PTAB activity." The absence is real as of this review, but it is also a live-status fact. A well-asserted patent eventually attracts IPRs, and 12,071,421 issued only on 2024-08-27 — it is young, not immune. Confirm the current E2E record before filing anything that depends on the absence of proceedings.

Confidence note: I have high confidence that no AIA trial proceeding was on file for US 12,071,421 as of the ODP ingest and as of my searches. I have not independently confirmed the current institution status of IPR2025-00945, -00946, -00947, or -00949, and I have not verified the granted claim set of 12,071,421 verbatim from the patent's claims — I therefore have not attributed any specific claim numbers to this patent.

I'll start by hunting for the recorded assignment records (reel/frame) and the correspondent of record.

The search results don't surface reel/frame numbers. Let me query the assignment databases more specifically.

I hit my search-step budget before I could pull the actual Assignment Center record fields (reel/frame, correspondent, execution dates). Below I report what is verifiable from the record and mark every unretrieved field explicitly rather than filling it in.

Important methodological caveat up front: I was not able to open the USPTO Assignment Center record page itself (https://assignmentcenter.uspto.gov) — it is a JS/API-gated application and my search tools returned only secondary mirrors. The post-issuance events below come from Google Patents legal events, which are derived from the USPTO assignment database. That means the conveyance type, assignor/assignee names, and recorded dates are reliable, but the reel/frame numbers, execution dates, and correspondent of record were not retrieved and are left blank. Per the operating rules, I am not reconstructing them from memory. (One useful side finding: a USPTO P-TACTS filing confirms the assignment URLs migrated — "On February 2, 2026 all older web URLs, assignments.uspto.gov and assignment.uspto.gov will no longer be available," so assignmentcenter.uspto.gov is now the only valid portal.)

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Inventors

Why "inferred": the assignment record names Helsinn Healthcare SA as original assignee, and the specificity of this disclosure (in-house netupitant prodrug process chemistry, including the two-equivalent-HCl salt stabilization insight) is consistent with a small in-house Helsinn team. But I could not retrieve the inventors' recorded assignment, so I cannot confirm from this session that each of inventors 1–7 executed an assignment to Helsinn. Treat the employer column as a working hypothesis, not a record citation.

Unusual pattern worth flagging: inventor #8, Valentino J. Stella (US), is the odd one out — a US academic, not a Swiss/Italian Helsinn scientist. The specification's own background cites U.S. Pat. No. 5,985,856 to the University of Kansas for "water soluble N-phosphoryloxymethyl derivatives of secondary and tertiary amines," which is the exact chemistry platform used here. Stella is the well-known University of Kansas prodrug chemist associated with that work. So the '421 patent appears to blend (a) Helsinn's netupitant process know-how with (b) an outside academic inventor whose home institution owns the cited enabling patent — yet the '421 patent is recorded as assigned to Helsinn alone. That is an ownership-chain diligence point (was there a KU assignment, a license, an inter-institutional agreement, or an inventorship/ownership defect?), and I did not verify any Stella→Helsinn or KU→Helsinn instrument. Flagging it as a question, not a finding.

Inventor-departure screen (the "all inventors gone within 12 months" fire-sale precursor): not present / no evidence. I found no record of any inventor severing ties or of an inventorship correction. Caveat: I could not run the employment-history check that would definitively rule this out.

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Original assignee

Helsinn Healthcare SA — Via Pian Scairolo 9, CH-6912 Lugano-Pazzallo, Switzerland (address confirmed in the Gland complaint, D.N.J. 2:22-cv-04635, ¶1). Swiss corporation; family-controlled (Braglia family) specialty pharma.

• Primary line of business: in-licensing and commercializing supportive-care and dermo-oncology products; explicitly a "business-to-business" / in-licensing model rather than a drug-discovery house (per the trial testimony of Dr. Calderari quoted in P-TACTS materials). It acquired worldwide netupitant rights from Roche in 2005, and netupitant's phosphate prodrug fosnetupitant is the direct downstream subject matter of the compound family this process patent serves.
• Did it ship a product embodying the claims? Yes. Helsinn holds NDA 210493 (first approved 2018-04-19) for fosnetupitant chloride hydrochloride / palonosetron hydrochloride, marketed as Akynzeo® for IV infusion (235 mg fosnetupitant / 0.25 mg palonosetron per 20 mL vial). Fosnetupitant is the chloride hydrochloride salt of GA1, the compound the specification calls "a particular preferred compound." The '421 process claims are directed to making the di-tert-butyl (chloromethyl) phosphate intermediate used to install the (phosphonooxy)methyl group on netupitant — i.e., a manufacturing-enabling patent for a product Helsinn actually manufactures and sells. Helsinn's 2025 sustainability report confirms own production facilities in Dublin, Ireland.
• Current status: Operating. No bankruptcy, no dissolution, no acquisition found. The 2023 security release (below) is consistent with ordinary secured-financing activity, not distress — but I did not locate an SEC filing or press release confirming the character of that facility (Helsinn Healthcare SA is Swiss and not an SEC registrant, so no 10-K/8-K exists for it).

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Assignment timeline

Two post-filing events are on the record for this patent. Both are reflected in Google Patents legal events for US 12,071,421 and were also reported in the earlier-generated sections of this analysis (no contradiction between sources). Reel/frame, execution dates, and correspondent were not retrievable — left as [not retrieved]. Correspondent is called out per the task because it is the key NPE tell; its absence forces signal 3 below to "unclear."

• 2022-12-30 (recorded) / executed [not retrieved] — Reel [not retrieved]/[not retrieved]

  • Conveyance: SECURITY INTEREST (Google Patents: "SECURITY INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor(s): HELSINN BIREX PHARMACEUTICALS LIMITED; HELSINN HEALTHCARE SA; HELSINN THERAPEUTICS (U.S.), INC.
  • Assignee: HAMILTON SA LLC (as collateral agent/secured party)
  • Correspondent: [not retrieved] — cannot evaluate the repeat-correspondent signal
  • Context: Securitization — a group-wide secured financing encumbering the Helsinn entities' IP; a security interest conveys no title, so ownership stayed with Helsinn.

• 2023-09-20 (recorded) / executed [not retrieved] — Reel [not retrieved]/[not retrieved]

  • Conveyance: RELEASE BY SECURED PARTY
  • Assignor(s): HAMILTON SA LLC
  • Assignee(s): HELSINN THERAPEUTICS (U.S.), INC.; HELSINN BIREX PHARMACEUTICALS LIMITED; HELSINN HEALTHCARE SA
  • Correspondent: [not retrieved]
  • Context: Release of lien — the encumbrance was discharged ~9 months after recordation; consistent with refinancing, a payoff of one collateral pool, or a collateral-substitution. No title change either way.

Gap I could not close: the original inventor→Helsinn assignment does not appear as an event against this patent number in the retrieved legal-events text. That is expected for a continuation — the inventors' original assignment was executed/recorded against the 2011–2012 ancestral applications (61/564,537 / 13/478,361) and is inherited by the continuation chain — but I did not confirm the recorder's entry, so I am stating it as an apparent absence, not a confirmed one. If, on the Assignment Center record, there is genuinely no inventor-assignment entry anywhere in this chain, that is itself a standing/enforceability diligence item — but I cannot make that call from this session's data.

No other conveyances found: no change of name, no merger, no license recordation, no transfer to an IP-holding LLC, no sale to a third party, no defensive-aggregator recordation.

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Timeline diagram

timeline
    title Ownership of US 12071421
    2011 : Priority application filed
    2012 : Parent application filed
    2022 : Continuation filed by Helsinn
         : Security interest to Hamilton SA LLC
    2023 : Hamilton releases security interest
    2024 : Patent issued to Helsinn Healthcare SA

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NPE / troll-pattern signals

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Verdict

Operating-company assertion.

The chain is an unbroken operating-company record: inventors → Helsinn Healthcare SA as sole assignee → a security interest to Hamilton SA LLC recorded 2022-12-30 (securitization; no title transfer) → release by secured party 2023-09-20 returning the encumbrance-free position to the three Helsinn entities. Helsinn is a Swiss specialty pharma that manufactures and sells the product this process serves (fosnetupitant chloride hydrochloride, i.e., GA1's salt, in Akynzeo® IV under NDA 210493), and it litigates its netupitant/palonosetron family against ANDA filers in its own name (Helsinn v. Gland, D.N.J. 2:22-cv-04635) — the opposite of an NPE posture. Caveat on the label: Helsinn is not yet asserting this specific patent (no litigation names '421, and as a process/manufacturing patent it is not an Orange-Book-listed patent for NDA 210493), and signal 3 could not be scored because the correspondent of record was not retrievable — so a reader should treat "no NPE pattern" as well-supported on signals 1, 2, 4, 5, 6, 7, 8 but not corroborated by the correspondent-recurrence test.

Verification links: search the record directly at https://assignmentcenter.uspto.gov (patent assignment search, query 12071421 or application 17/699,522); the legacy assignment.uspto.gov / assignments.uspto.gov endpoints were retired effective 2026-02-02. Cross-check the same two events on the Google Patents legal-events tab at https://patents.google.com/patent/US12071421/en.

I'll search for the USPTO record and the patent's cited references.

Let me retrieve the patent's cited references (front-page citations) from the patent databases.

Let me get the full citation list with dates and the granted claim text.

Prior Art Analysis — US 12,071,421 B2

Identification confirmed (literal match, no auto-correction): The USPTO/Google/Espacenet/PubChem records retrieved are for US 12,071,421 B2, application 17/699,522, filed 2022-03-21, granted 2024-08-27, titled "Process for the synthesis of substituted chloromethyl dialkylphosphates," assignee Helsinn Healthcare SA. This is the same patent number specified in the task; no similar-numbered record (e.g., 12,071,412 / 12,074,121) was substituted.

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⚠️ Critical caveats before the analysis (please read)

1. The authoritative granted claim set is still not in hand. This was flagged as unresolved in the previously generated sections, and it remained unresolved in this session — the claim column of the granted text could not be retrieved. I therefore will not assign anticipation to specific claim numbers. Any "potentially anticipates" statement below is expressed against the claim categories the record supports (process-for-chloromethyl-dialkylphosphate claims; possibly compound/composition claims), not against verified claim language. Mapping to numbered claims requires the claims section of the granted PDF/PatentCenter.
2. A front-page citation is not automatically § 102 prior art. Cited references may be cited for § 103 (obviousness), as background, or as "documents defining the general state of the art" — the Art-unit/ISR categories distinguish these. Treating a citation as anticipatory without the claim text and the reference's disclosure is a category error I am deliberately avoiding.
3. Date verification was partial. I could not open every cited reference's front page in this session. Dates I am confident of are marked [V]; the rest are marked [UV — not verified in this session] and given as best-known with an "est." qualifier. Do not treat the unverified dates as record-grade.
4. Citation-list provenance. The list below is reproduced from the PubChem patent record for US-12071421-B2 (https://pubchem.ncbi.nlm.nih.gov/patent/US-12071421-B2). PubChem labels the section "12 Citations" but renders ~25 patent documents plus ~15 non-patent items — the label appears to refer to a subset, and the rendered list likely mixes patent citations, family members, and cited-by/citing items. I report it literally and flag the ambiguity rather than silently curating it.

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A. Patent references listed for US 12,071,421 B2

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B. Non-patent literature listed for US 12,071,421 B2

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C. The most relevant prior art, and the priority problem that governs § 102

Ranked by likely significance:

1. US 5,985,856 (Stella/Univ. Kansas) + the Krise/Stella phosphonooxymethyl-prodrug paper — the two references that squarely cover "(phosphooxy)methyl prodrugs of tertiary amines" and chloromethyl dialkyl phosphate intermediates. The '421 specification expressly frames its own novelty against this art: the prior art "required multiple synthetic steps… including requiring the use of proton scavengers… and requiring strong acid to deprotect the phosphate group." That is a classic § 103 argument structure, and it means these references are the primary validity fulcrum against the process claim, not mere background.
2. US 6,747,026 (Roche, mono-N-oxides) and US 6,297,375 (Roche, 4‑phenylpyridines) — the primary art for the compound subject matter (GA4–GA8 and netupitant-derived structures). The formula-(I) proviso requiring more than one N-oxide when a non-pyridine N-oxide is present appears purpose-built to avoid anticipation by '026.
3. Helsinn's own family: US 8,426,450 B1 and US 9,403,772 B2 — central to validity, but not third-party art so long as priority is intact.

The controlling issue — priority / § 102(a)(2): US 12,071,421 is a continuation-in-part. Its specification states it "claims priority to U.S. Provisional Application 61/564,537… and is a continuation in part of U.S. Non-provisional application Ser. No. 13/478,361." A CIP's new matter is only entitled to the CIP's actual filing date for that matter. If the chloromethyl-dialkylphosphate process claims were added as new matter in a later link of the chain (the record shows the chain running 15/194,984 → 15/874,325 → 16/228,835 → 16/896,135 (2020-06-08) → 17/699,522 (2022-03-21)), then the effective filing date of those claims is not 2011-11-29. Consequences:

• Family members become prior art. US 8,426,450 (2013), US 9,403,772 (2016), WO 2013/082102, WO 2013/177224, and US 2017/0050993 (all listed as citations) could then qualify under § 102(a)(2) (or § 102(a)(1) where published before the claim's effective date).
• Conversely, the art that predates 2011-11-29 (US 5,985,856; the Krise paper; US 6,297,375; US 6,747,026; Hoffmann 2006; Giuliani 2011) is prior art regardless of which link the claims get.
• Google Patents shows the anticipated expiration as 2032-05-23, i.e., a 20-year term anchored to the 2012-05-23 parent filing — not to the 2022 filing. That is consistent with the disclosure claiming the earlier chain, but it says nothing about whether the process claims are supported by the 2011/2012 disclosure. That question can only be answered by comparing the granted process claims to the 2012 parent's written description.

Bottom line on anticipation: On the record available, I can identify the references to test for anticipation (principally US 5,985,856 and the Krise/Stella paper against the process claims; US 6,747,026 and US 6,297,375 against the compound claims), and I can identify the proviso in formula (I) as an apparent anticipation-avoidance amendment. I cannot state that any reference anticipates any numbered claim, because (a) the granted claim text was not retrieved, and (b) the full disclosures of the cited references were not opened in this session.

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D. What is needed to close this out

1. Pull the granted claims for US 12,071,421 B2 (USPTO PatentCenter or the granted-PDF "Claims" section). Without the claim numbers I will not manufacture a § 102 mapping.
2. Pull the front-page "(56) References Cited" block from the granted PDF, which separates U.S. Patent Documents / Foreign Patent Documents / Other Publications and shows examiner-vs-applicant citation — more reliable than the PubChem aggregate.
3. Pull the PCT/US2012/066778 ISR (2013-01-03) to see which references the examiner categorized "X" (anticipatory) versus "Y" (obviousness) — the fastest route to the true § 102 set.
4. Compare the granted process claims against the 2012-05-23 parent's specification to settle the CIP priority question, which determines whether the Helsinn family members (US 8,426,450; US 9,403,772) are § 102(a)(2) art against the '421 claims.

Integrity note: No patent number or identifier in this response was auto-corrected; the patent addressed is literally 12,071,421. Where I could not verify a date or a reference's content, I have said so explicitly rather than asserting it. The prior-section finding that no CAFC docket names this patent and that it is not listed in the Akynzeo Orange Book entries I located is consistent with this being a process/manufacturing patent, which also explains why its citation list is dominated by chemistry/prodrug-art references rather than formulation or method-of-treatment patents.

I'll ground this analysis by pulling the granted claim text and the key prior-art references before reasoning.

Let me pull the full granted claim set and check the key prior-art references cited on the patent page.

Let me retrieve the exact claim 1 language and identify the prosecution-cited prior art on the patent's own page.

Obviousness Analysis — US 12,071,421 B2 under 35 U.S.C. § 103

Analyst note on dates: this task specifies "Current Date: April 26, 2026," while the session metadata says 2026‑09‑30. I flag the discrepancy rather than reconciling it, per the no‑auto‑correction rule. All identifiers below are reproduced literally as found.

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1. What is actually being tested (claim scope)

I was able to retrieve part of the granted claim set from a secondary source, which materially changes the analysis from the earlier "Litigation summary"/"Patent summary" sections (which could not verify any claim text).

From Justia's copy of the granted patent (https://patents.justia.com/patent/[12071421](/patent/12071421)):

• Claim 1 is a process claim. Its variable definitions recite that R²⁰⁰ is C₁‑₆ alkyl (optionally substituted with one or more R¹⁰³), R³⁰⁰ is C₁‑₆ alkyl (optionally substituted with one or more R¹⁰³), each R¹⁰³ is independently halogen, CN, NO₂, C(O)R¹⁰⁴, C(O)NR¹⁰⁴R¹⁰⁵, C(O)OR¹⁰⁴, NR¹⁰⁴R¹⁰⁵, NR¹⁰⁴C(O)R¹⁰⁵, NR¹⁰⁴S(O)₂R¹⁰⁵, O⁻, OR¹⁰⁴, SR¹⁰⁴, S(O)₂R¹⁰⁴, S(O)₂NR¹⁰⁴R¹⁰⁵, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, and each R¹⁰⁴ is independently H, halogen, CN, NO₂, alkyl, alkyl(hydroxy)… etc. The claim recites steps (a), (b) and (c).
• Claim 2 depends on claim 1: "wherein, in step (a): R²⁰⁰ is C(CH₃)₃; R³⁰⁰ is C(CH₃)₃; and the inorganic acid is hydrochloric acid."
• Claim 3 depends on claim 1: "(i) in step (a), the first C₁‑C₆ alcohol solvent is methanol; (ii) in step (b), the second C₁‑C₆ alcohol solvent is methanol; and (iii) in step (c), the C₁‑C₆ aldehyde solvent or C₁‑C₆ ketone solvent is acetone."

⚠️ Verification gap (must be carried forward): the verbatim preamble and the (a)/(b)/(c) step language of claim 1 were not retrieved in full. I have the variable definitions and the dependent-claim language, and the abstract supplies the step sequence — "reacting a dialkylphosphate salt with an acid to obtain the corresponding ester of phosphoric acid, reacting the ester with a quaternary ammonium hydroxide base to form a monobasic salt, and reacting the monobasic salt with chloroiodomethane to form the corresponding chloromethyl dialkyl phosphate" — but the claim's exact recitations of the acid (inorganic), the quaternary ammonium hydroxide, and the solvent classes are reconstructions from the abstract + claims 2–3, not a confirmed quotation. A definitive §103 opinion requires the granted claim text from the USPTO PatentCenter / granted PDF (https://patents.google.com/patent/US12071421/en, Claims section), which I could not open here.

Working claim-1 model (subject to the caveat above):

(a)  (RO)2P(O)O⁻ M⁺   +  inorganic acid  —→  (RO)2P(O)OH        [in a C1-C6 alcohol]
(b)  (RO)2P(O)OH      +  R4N⁺OH⁻         —→  (RO)2P(O)O⁻ ⁺NR4  [in a C1-C6 alcohol]
(c)  (RO)2P(O)O⁻ ⁺NR4 +  ClCH2I          —→  (RO)2P(O)OCH2Cl   [in a C1-C6 aldehyde/ketone solvent]

Where R²⁰⁰/R³⁰⁰ are C₁‑₆ alkyl (claim 2 narrows to tert‑butyl); i.e., the commercially important product is di‑tert‑butyl (chloromethyl) phosphate.

This is consistent with the granted title ("Process for the synthesis of substituted chloromethyl dialkylphosphates") and resolves the internal inconsistency flagged in the earlier Patent summary: the granted claims are process-focused; the broad formula (I)/(II)–(VI) and GA1–GA8 compound subject matter discussed in the specification does not appear in claims 1–3. Whether any compound claims survive elsewhere in the granted set remains unverified.

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2. Threshold issue: which references qualify as prior art

Effective filing date is dispositive here, and it is not self-evident:

• Earliest priority is 2011‑11‑29 (US 61/564,537), with a 2012‑05‑23 non-provisional parent.
• The application on file (17/699,522, filed 2022‑03‑21) is, on its own face, a continuation‑in‑part. CIP claim language that is not supported by the 2011/2012 disclosure is not entitled to the 2011 date and instead gets the 2022 filing date.

Consequence: if claim 1 is fully supported in the 2011/2012 disclosure, post‑2011 publications (notably US 2015/0315218 A1) are not §102/§103 art. If claim 1 was written to embrace process features first described in the CIP matter, the 2022 date opens up a materially larger art set. I cannot resolve this without the priority‑support record, so I analyze both scenarios and label which references depend on which date.

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3. The prior art

3A. Art identified in the Background/"Description of Related Art" of the '421 page itself (per the task instruction)

3B. Art surfaced by search that is most probative against the granted process claim (⚠️ not literally quoted in the '421 Background section — flagging the distinction)

Data-integrity flag: I verified the disclosure content of the 3B references from search snippets, but I did not verify their exact priority chains or confirm that they appear on the '421's own "Prior Art"/"Citations" list on Google Patents. The task directed me to "use the results from the Prior Art section of this page"; the page's Background section names only the three US patents and the two journal articles in 3A. The 3B set is offered as the art that a §103 attack would actually be built on, and is labeled as such.

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4. Element-by-element mapping

Claim 1

Every element of claim 1 is disclosed or is a routine, predictable selection. There is no missing element that requires a leap.

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5. Obviousness combinations and motivation to combine

Combination A (strongest) — WO 2005/090367 + US 8,168,615 ("improved preparation") + the commercial availability of quaternary ammonium dialkyl phosphates

Primary reference: WO 2005/090367 A1 (and its US siblings US 8,158,615 / US 8,461,333 / US 7,745,625), which discloses step (c) essentially verbatim, with the exact di‑tert‑butyl species and the exact chloroiodomethane reagent.

Secondary reference: US 8,168,615 / US 2015/0315218 ("improved preparation… utilizes less expensive ditertbutyl potassium phosphate… the starting materials… are more economical and less hazardous and the final product is produced in higher purity").

Motivation, articulated as a POSITA would:

1. Same field, same reagent, same purpose. All references are directed to making the same molecule — di‑tert‑butyl (chloromethyl) phosphate — as the alkylating reagent for installing a POM promoiety on a tertiary amine. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) ("familiar elements… according to known methods"); In re Bigio, 381 F.3d 1320 (Fed. Cir. 2004) (same field of endeavor).
2. Explicit, articulated cost/purity motivation. US 8,168,615 does not merely make the substitution obvious — it states the reason: the potassium salt is cheaper and the product purer. That is precisely the '421's own stated rationale ("the quality of phosphate ester compositions from commercial sources is too low to provide acceptable yields"). Under KSR, a "known technique… improved in the same way as the improvement in the primary reference" is obvious, and an express motivation in the art is the paradigm case.
3. The alkali‑metal → quaternary‑ammonium conversion is a predictable salt metathesis. A POSITA knows (a) the tetraalkylammonium dialkyl phosphate is the species that is soluble in the aprotic organic medium (DME, acetone, THF, benzene) required for the SN2 displacement on ClCH₂I, and (b) potassium dialkyl phosphate is not. Converting K⁺ to R₄N⁺ — classically by liberating the free acid with HCl in methanol (a step the '421 performs and that precipitates KCl) and titrating with R₄NOH — is a routine ion‑exchange step with a predictable result. US 8,461,333's use of n‑Bu₄NHSO₄ alongside K di‑tert‑butyl phosphate is direct evidence that the K⁺→R₄N⁺ conversion was known and conventional in this very synthesis.
4. Art-recognized interchangeability of the two salt forms. JP 5046959 B2 describes the TBA salt/ClCH₂I route and the K salt/chloromethyl chlorosulfonate route as equally usable alternatives for the same product — i.e., the art treats the cation and the chloromethylating agent as independently selectable, which is a KSR "obvious to try" situation with a finite number of identified, predictable solutions and a reasonable expectation of success.
5. Solvent choice is routine optimization. Methanol for the acid/salt steps and acetone (claim 3) for the displacement are among the solvents the art expressly lists. In re Aller, 220 F.2d 454 (CCPA 1955) (optimizing a recognized process variable is not inventive absent unexpected results); In re Boesch, 617 F.2d 272 (CCPA 1980).

Conclusion for Combination A: claim 1 would have been obvious; claims 2 and 3 would have been obvious as express species/solvent selections recited in or suggested by the art.

Combination B — US 5,985,856 + US 6,297,375 (+ US 6,747,026) for any compound/method-of-treatment claims

If any granted claim is directed to the POM prodrug genus, to GA1, or to the N‑oxides (the specification's formula (I)/(VI) and GA1–GA8 material), the obviousness case is if anything stronger and simpler:

• US 5,985,856 claim 5 discloses a method of derivatizing a tertiary amine with a chloromethyl phosphate reagent bearing tertiary‑butyl protecting groups — the exact reaction the '421 claims to have rendered "one‑step, acid‑free."
• US 5,985,856 claim 1 / formula VIa/VIb discloses the POM quaternary ammonium compound genus with an external cation X and anion A, and the internal‑salt (zwitterionic) embodiment.
• US 6,297,375 supplies netupitant as a tertiary‑amine 4‑phenyl‑pyridine NK₁ antagonist; US 6,747,026 supplies mono‑N‑oxide derivatization of that chemotype.
• Motivation: the '421 Background, and '856 itself, frame the problem identically — tertiary‑amine drugs are poorly soluble near physiological pH; POM derivatization of a tertiary amine produces a zwitterionic/quaternary species with high aqueous solubility; a POSITA seeking a soluble, phosphatase‑cleavable form of netupitant would have applied '856's method to '375's compound. KSR; In re Kao, 639 F.3d 1057 (Fed. Cir. 2011) (predictable improvement).

Combination C — + phase‑transfer catalysis art

US 8,461,333 (n‑Bu₄NHSO₄ + K di‑tert‑butyl phosphate + CMCS) and US 8,168,615 (n‑Bu₄NI as iodide source) additionally supply the teaching that the K salt and a quaternary ammonium species are used together in the same pot. This closes any residual argument that the cation swap in step (b) was somehow outside routine practice.

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6. The strongest non-obviousness defenses (and how they cut)

I would be doing the analysis a disservice not to state these:

1. "Teaching away" from chloroiodomethane. US 8,168,615/US 2015/0315218 criticizes the earlier TBA/chloroiodomethane route: a ≥5‑fold excess of the reagent, ≥50 equivalents of chloroiodomethane, and "side products… removed using silica gel chromatography, a tedious, time consuming, and expensive operation especially on reactions of increasing scale," whereas the improved CMCS route gives product "isolated in pure form via convenient distillation." A prima facie argument exists that this criticizes and discourages the very route claim 1 claims. In re Fulton, 391 F.3d 1195 (Fed. Cir. 2004); DePuy Spine v. Medtronic, 567 F.3d 1314 (Fed. Cir. 2009).
   • Rebuttal: the criticism targets the scale of the reagent excess and the chromatography, not the underlying ClCH₂I chemistry; the same reference still discloses the ClCH₂I route. Also, the '421 does not claim reduced chloroiodomethane equivalents — its claimed benefit is the purity of the in‑situ‑prepared ammonium salt, a different problem. But if the applicant can show the art's teaching was "go to CMCS/distillation," this is the most plausible escape hatch.
2. Unexpected results / the "unstable dibasic salt" finding. The specification asserts that "the prior art preferred the use of dibasic salts of (phosphooxy)methyl substituents for quaternary ammonium salts in prodrugs," and that the present inventors found "such salts are unstable and reform the underlying drug during storage," motivating the bis‑HCl (chloride hydrochloride) form — with FIG. 1 plotting degradation over days for the disodium, lysine, calcium, phosphate and chloride‑hydrochloride salts. If the granted claims extend to a bis‑HCl salt form or to a specifically stabilized composition, that is a potential unexpected‑results showing. In re Soni, 54 F.3d 746 (Fed. Cir. 1995).
   • Limitation: this evidence attaches to the salt/product, not to the process of claims 1–3 as I have been able to read them. Unless it is tied to process performance, it lacks nexus for the process claims. In re Huang, 100 F.3d 135 (Fed. Cir. 1996) (nexus required).
3. Commercial success (Akynzeo/fosnetupitant). Potential secondary consideration, but the nexus is weak: claim 1 covers a manufacturing intermediate, and the akynzeo commercial success is attributable to the active prodrug/netupitant combination, not to the route by which di‑tert‑butyl chloromethyl phosphate is made. In re GPAC, 57 F.3d 1573 (Fed. Cir. 1995).
4. Priority-date gating. If claim 1 is entitled to 2011‑11‑29, then US 2015/0315218 A1 is not prior art, and the §103 case rests on WO 2005/090367 + US 8,158,615/US 8,461,333 + the knowledge that quaternary ammonium dialkyl phosphates are the reactive species. That case is still strong but the express "cheaper potassium salt / higher purity" motivation is lost. If instead the claim relies on CIP matter, the full motivation is available. This is the single most outcome‑determinative fact I could not verify.

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7. Reasons for allowance (my read, and why it may have been granted anyway)

The '421 appears to have been examined by a chemical‑process examiner (Primary Examiner Douglas M. Willis, per the Justia record) with an art unit focused on C07F9 (phosphorus compounds). The grant is most plausibly explained by:

• A remarkably late filing inside a very long priority chain. The application was filed 2022‑03‑21 on a 2011 priority family. Examiners searching the 2011‑dated art may not have surfaced the WO 2005/090367 family's Example language in the same way a targeted reagent search would, precisely because those references are in the antiviral‑prodrug field, not the NK₁ field — an art‑unit/cross‑discipline blind spot of the kind that frequently underlies §103 attacks.
• The claim's variable definitions (R¹⁰³/R¹⁰⁴ lists, the "O⁻" moiety) are broad and Markush‑heavy, which can obscure that the commercial species is simply the di‑tert‑butyl ester.
• No apparent consideration of the WO 2005/090367 family in the Background section, which cites only '375, '026 and '856 — the three references the patentee itself admits, and none of which discloses the di‑tert‑butyl chloromethyl phosphate synthesis with specificity.

That procedural posture (a narrow, mechanical process claim over a crowded reagent‑synthesis art) is a classic candidate for an IPR. Note the unresolved relevance of the earlier‑flagged Azurity v. Helsinn IPR cluster (IPR2025‑00945 through ‑00949) — the earlier Patent summary could not confirm whether US 12,071,421 is among the challenged patents. Given that the '421 is a process patent not listed in the Orange Book for Akynzeo, it is unlikely to be an IPR target, but I did not verify the petition captions.

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8. Bottom line

Claims 1–3 (process claims for making di‑tert‑butyl (chloromethyl) phosphate): obvious under §103, subject to two verifications.

• Primary combination: WO 2005/090367 A1 (discloses step (c) verbatim: tetrabutylammonium di‑tert‑butyl phosphate + chloroiodomethane → di‑tert‑butyl chloromethyl phosphate) in view of US 8,168,615 / US 2015/0315218 (express teaching that the less expensive potassium di‑tert‑butyl phosphate is a preferred, higher‑purity starting material) in further view of US 8,461,333 (n‑Bu₄N⁺ phase‑transfer species used with K di‑tert‑butyl phosphate) and JP 5046959 B2 (the two cation/chloromethylating‑agent routes described as interchangeable).
• Motivation: same reagent, same purpose, same field; express cost/purity rationale in the art mirroring the patent's own stated rationale; salt metathesis (acid → R₄NOH) as a predictable, conventional step; the reactive tetraalkylammonium species being the known prerequisite for the SN2 in aprotic solvent; and solvent selection as routine optimization (KSR; In re Aller).
• Dependent claims 2–3: obvious — the di‑tert‑butyl ester and HCl are the art's express species, and acetone is expressly listed as a suitable solvent in the art.
• Any residual compound/method claims (formula (I)/(VI), GA1–GA8): obvious/invalid over US 5,985,856 (POM methodology and compound genus) in view of US 6,297,375 (netupitant) and US 6,747,026 (mono‑N‑oxides).

Confidence: moderate‑to‑high that a properly framed §103 challenge succeeds on the process claims if the WO 2005/090367 family is available as art — which turns on (i) whether claim 1 gets the 2011 priority date (determines whether US 2015/0315218 is in play and how much explicit motivation exists) and (ii) the exact claim 1 text, which I could not verify. Confidence in the verbatim claim‑1 language: low — retrieve from USPTO PatentCenter before relying on this opinion.

Two items flagged for correction of the earlier sections: (1) the earlier "Patent summary" doubted whether compound claims survived prosecution; the Justia record now shows claims 1–3 are process claims, so the compound‑claim hypothesis should be downgraded. (2) The earlier sections recorded no litigation for this number and could not tie this patent to the Azurity IPRs — nothing in this analysis changes that, but a §103 analysis is the more productive line of attack on this patent than an infringement theory, because the claim is a manufacturing step likely to be practiced in a supplier's plant rather than by a US ANDA filer.