Targeted Protein Degradation Patents: Leaders & White Space 2026
A data-backed look at E3 ligase recruitment patents in targeted protein degradation: who leads filings, how concentrated the field is, and where claim space remains open.
Filing growth = 2021 (45 records) → 2024 (48); 2024 is the last year we treat as complete. Top-5 share = the 5 largest assignees ÷ all 267 records in scope (CR5), not the ranked leaders only.
What the E3 ligase recruitment patent record shows
Targeted protein degradation depends on recruiting an E3 ligase to a target protein so the cell’s own machinery destroys it. The patent record for this specific mechanism — 267 records published between 2015 and the 2026 cut-off — is dominated by cereblon-based ligand chemistry and bifunctional PROTAC-style compounds, with a smaller but active thread of antibody-conjugate and fetal liver kinase degrader claims. Most filings are framed as medicinal preparations with a stated therapeutic activity, rather than as standalone chemical compositions, which shapes how narrow or broad a given claim can be read.
Filing activity rose steadily through the late 2010s and peaked at 48 records in 2024, the last year that can be treated as materially complete given the roughly 18-month lag between filing and publication. The most recent years in the trend will fill in further as pending applications publish, so any read of 2025 or 2026 as a slowdown would be premature.
Filing concentration, technology mix and where applicants file
The dataset spans 267 published records across 66 ranked assignees, six major receiving offices and eight IPC subclasses. The patterns below describe where claim density is heaviest and where the field remains comparatively open.
A plateau, not a slowdown
Filings climbed from 23 in 2017 to a peak of 48 in 2024, with growth of just 7% across the 2021-to-2024 window. That is a maturing rate of new filing rather than an accelerating one, though the 2025-2026 figures are still incomplete due to publication lag.
Publication lags filing by roughly 18 months, so 2025 onwards are still filling in. Growth rates on this page therefore end at 2024; running them to the last bar would understate the field.
Medicinal framing dominates the class mix
A61K (medicinal preparations) appears on 79.0% of records and A61P (therapeutic activity) on 69.3%, meaning most applicants claim both a compound and its disease use. Heterocyclic chemistry under C07D covers 48.3% of records, while peptide and protein claims under C07K sit at 25.5%. Organo-metallic compound claims under C07F and nanotechnology applications under B82Y are each below 5%, marking the thinnest-claimed corners of the space.
Shares are the percentage of the 267 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
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Compounds and methods for FBXO22-mediated protein degradation
In some aspects, provided herein compounds (PROTACs) targeting the E3 ligase FBXO22 and uses thereof. In some aspects, provided herein are methods of identifying E3 ligases and compounds that support targeted protein degradation.Filed by Northwestern University and published 2025-03-20, this record targets FBXO22 rather than the cereblon or VHL pathways that dominate the most-cited records, illustrating how newer entrants are claiming alternative E3 ligases to work around crowded chemistry.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2018144649A1 | Cereblon ligands and bifunctional compounds comprising the same | 357 |
| 2 | WO2016146985A1 | Derivatives of 1-[(cyclopentyl or 2-pyrrolidinyl)carbonylaminomethyl]-4-(1,3-thiazol-5-YL) benzene which are … | 249 |
| 3 | US20180215731A1 | Cereblon ligands and bifunctional compounds comprising the same | 218 |
| 4 | WO2017201449A1 | Protac antibody conjugates and methods of use | 213 |
| 5 | WO2018118598A1 | Compounds and methods for the targeted degradation of fetal liver kinase polypeptides | 111 |
| 6 | WO2017211924A1 | Novel compounds | 104 |
| 7 | WO2018051107A1 | Fluorohydroxyproline derivatives useful in the preparation of proteolysis targeted chimeras | 73 |
| 8 | US20180050021A1 | Derivatives of 1-[(cyclopentyl or 2-pyrrolidinyl)carbonylaminomethyl]-4-(1,3-Thiazol-5-yl) benzene which are … | 71 |
| 9 | US20180256586A1 | Compounds and methods for the targeted degradation of fetal liver kinase polypeptides | 64 |
| 10 | WO2018033556A1 | Novel compounds | 61 |
Citation counts favour older, more-searched records and should be read as a signal of influence within this corpus, not as a measure of current commercial importance.
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Three patterns stand out once the ranking, the IPC mix and the citation leaders are read together: concentration at the top, a chemistry-heavy claim style, and citation leadership sitting with cereblon-ligand chemistry rather than newer ligase targets.
The field is led by a small group, not one dominant player
The leader holds 40 records against a fifth-place figure of 17 and a tenth-place figure of 8, a steep drop-off that indicates strong but not monopolistic control. A long tail of the remaining ranked assignees each hold small numbers of records, leaving room for focused entrants that avoid the cereblon-chemistry core.
Most claims are written as medicinal preparations with therapeutic use
Combined A61K and A61P coverage means the bulk of filings pair a compound claim with a stated disease application, which narrows the practical scope of any single patent but also means broad composition-only claims are comparatively rare.
Cereblon-ligand chemistry anchors the most-referenced prior art
The most-cited records in the dataset are cereblon ligand and bifunctional compound filings, several exceeding 200 citations, while antibody-conjugate and kinase-degrader records trail behind. New filings that build on FBXO22 or other non-cereblon ligases sit outside this citation core, for now.
Organo-metallic and nanotechnology claims remain thin
C07F organo-metallic compound claims and B82Y nanotechnology application claims each sit under 5% of records, well below the heterocyclic and peptide classes. That gap suggests these framings have not been heavily tested as claim strategies in this specific mechanism.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to targeted protein degradation: e3 ligase recruitment patent landscape, with the prior art for and against each one.
Where to take this analysis
The figures above describe the shape of the field. Turning that into a filing or licensing decision means drilling into specific claims, specific assignees, and the branches that are not yet crowded.
Map a specific E3 ligase target against existing claims
Cereblon and VHL chemistry is dense with prior art; ligases like FBXO22 have far fewer filings against them. Checking a target ligase against the full claim set before drafting avoids collision with the most-cited records.
Explore E3 ligase claims in EurekaTrack the assignees building co-filing relationships
Several academic-industry pairs recur across the co-assignee data, pointing to active collaboration structures worth watching for licensing or partnership signals.
Review assignee relationships in EurekaCommon questions on E3 ligase recruitment patents
The assignee ranking in this dataset covers 66 companies across 267 published records, with the leader holding 40 records. The top five assignees combined hold 123 records, or 46.1% of all records in scope, which is a meaningful concentration but well short of a monopoly. Below the top ten, which together hold 65.9% of records, filing activity spreads across a long tail of smaller and single-filing entrants, including several academic institutions.
Filings rose from 23 in 2017 to a peak of 48 in 2024, but the growth rate slowed to just 7% between 2021 and 2024. That is consistent with a field settling into steadier annual filing rather than one still accelerating. Figures for 2025 and 2026 will read as lower, but that reflects the roughly 18-month lag between filing and publication rather than an actual drop in activity.
The two largest IPC subclasses are A61K, medicinal preparations, covering 79.0% of the 267 records, and A61P, therapeutic activity of compounds, covering 69.3%. Heterocyclic chemistry under C07D appears on 48.3% of records and peptide and protein claims under C07K on 25.5%. Because a single record can carry multiple IPC classes, these shares add up to more than 100% and should not be summed as if they were exclusive categories.
The most-cited record in this dataset is a cereblon ligand and bifunctional compound filing cited 357 times, followed closely by a related cereblon ligand filing and a thiazole-benzene derivative patent. A PROTAC antibody conjugate filing and a fetal liver kinase degradation patent round out the most-cited group. High citation counts in a corpus like this tend to favour older, more heavily searched filings, so they signal historical influence on the field's chemistry more than current commercial weight.
The IPC data points to organo-metallic compound claims under C07F and nanotechnology application claims under B82Y as the thinnest-claimed branches, each under 5% of the 267 records. Ligases outside the cereblon and VHL pathways, such as FBXO22, also show far fewer filings than the citation leaders in this corpus. Neither observation guarantees an easy path to allowance, but both mark areas with less prior art density to search against.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.