PROTAC Patents: Who Leads, Where the Gaps Are 2026
- Filing already peaked. 2020 recorded 32 filings, the high point of the trend; the 2022 midpoint of 24 shows momentum since then is flat to declining, not accelerating.
- The top five hold 43.4% of the field. 72 of 166 records in scope sit with the five leading assignees, with the leader alone on 28 — concentrated enough that new entrants are filing around, not through, that group.
- Almost everything sits inside two IPC subclasses. A61K appears on 87.3% of records and C07D on 75.3%, so the differentiating claim language is rarely in the broad medicinal-preparation or heterocyclic-compound classes themselves.
What the PROTAC patent record actually shows
Targeted protein degradation patents built around E3 ligase recruitment, ternary complex formation, the hook effect, degrader oral bioavailability and resistance mechanisms form a comparatively young but already top-heavy filing record. The dataset in scope covers 166 published records from 2015 through the 2026-07-31 cut-off, filtered to IPC classes A61K31, C07D401 and A61P35. Publication lags filing by roughly 18 months, so the most recent filing year is undercounted by construction, not because interest has stopped.
Within that record, filing activity rose through the late 2010s, peaked in 2020, and has not regained that level since — the 2022 midpoint of 24 filings sits well under the 2020 peak of 32. Technology composition is dominated by two IPC subclasses that together cover the great majority of records, while several smaller subclasses — steroids, peptides and proteins, acyclic compounds, genetic engineering and analytical methods — carry a small but non-trivial share of the filings and mark where claim language diverges from the mainstream small-molecule degrader chemistry.
Filing trend and technology composition
Two views of the same 166-record dataset: how filing volume has moved year over year, and which IPC subclasses carry the claims.
A 2020 peak, then a plateau
Filings rose from 3 in 2017 to a peak of 32 in 2020. The 2022 figure of 24 sits below that peak, and the count for the most recent year is partial by definition given publication lag — read the tail of the trend as incomplete, not as a real decline to near zero.
Two subclasses carry most of the claim volume
A61K (medicinal preparations) appears on 87.3% of the 166 records and C07D (heterocyclic compounds) on 75.3%; A61P (therapeutic activity) follows at 59.0%. Because a single record can carry several IPC classes, these shares add to more than 100% of the record total — smaller subclasses such as C07J (steroids, 9.6%) and C07K (peptides & proteins, 4.8%) mark where filings depart from the mainstream heterocyclic degrader chemistry.
Shares are the percentage of the 166 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Targeted Protein Degradation (PROTAC) with Eureka
This page is one run against one query. Ask Eureka your own question about targeted protein degradation (protac) and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this dataset
Proteolysis targeting chimera (PROTAC) for degradation of Aurora A-kinase
This filing claims a PROTAC built on the structure AAB-L-E3B: a binding unit for Aurora A-kinase joined through a linker to an E3-ubiquitin ligase binding unit built on thalidomide or one of its analogs (lenalidomide, pomalidomide, apremilast). The linker is specified as an alkyl or polyalkyl ether residue, including variants where a C-C bond is replaced with a C=C double bond.Filed by Julius-Maximilians-Universitaet Wuerzburg, published 2023-04-20.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20160045607A1 | Estrogen-related receptor alpha based protac compounds and associated methods of use | 352 |
| 2 | WO2017079267A1 | Proteolysis targeting chimera compounds and methods of preparing and using same | 315 |
| 3 | US20160176916A1 | Methods to induce targeted protein degradation through bifunctional molecules | 258 |
| 4 | US20180134684A1 | Methods to induce targeted protein degradation through bifunctional molecules | 160 |
| 5 | US20160243247A1 | Methods to induce targeted protein degradation through bifunctional molecules | 138 |
| 6 | US20180085465A1 | Methods to induce targeted protein degradation through bifunctional molecules | 127 |
| 7 | US9694084B2 | Methods to induce targeted protein degradation through bifunctional molecules | 96 |
| 8 | US20180009779A1 | Methods to induce targeted protein degradation through bifunctional molecules | 90 |
| 9 | US9821068B2 | Methods to induce targeted protein degradation through bifunctional molecules | 88 |
| 10 | WO2020041331A1 | Proteolysis targeting chimeric (protac) compound with e3 ubiquitin ligase binding activity and targeting alph… | 82 |
Ranked by citation count within the searched corpus. Older filings accumulate more citations by virtue of age, so treat this as a signal of influence on the field's early claim language, not of current commercial relevance.
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Browse MCP servers →What the concentration and citation data mean for filing strategy
The ranking, the citation table and the co-filing pairs point to the same conclusion from three different angles: this is a field with an entrenched early cohort and a long tail testing narrower chemistry around it.
The leading cohort is hard to file around directly
The top five assignees combined account for 72 of the 166 records in scope, with the single leader holding 28. A ranked field of 72 companies means the remaining share is spread thin across many single- or few-filing entrants rather than a second concentrated tier.
Filing has plateaued since the 2020 peak
Volume built steadily from 3 filings in 2017 to 32 in 2020, then eased. A midpoint of 24 in 2022 confirms the pattern is flat-to-declining rather than a rebound, though the most recent year is necessarily undercounted by publication lag.
Early bifunctional-molecule filings anchor the citation graph
The most-cited records in this dataset describe early estrogen-receptor and bifunctional-molecule degrader chemistry, several exceeding 100 citations each. That weight reflects age within the searched corpus as much as ongoing relevance — cite them as foundational prior art, not as the current state of the art.
Co-filing is limited and concentrated in a few pairs
Only ten co-assignee pairs appear across the dataset, and the strongest pair shares just 6 records. Collaboration is not a major structural feature of this field yet — most organisations here are filing independently rather than jointly.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to targeted protein degradation (protac), with the prior art for and against each one.
Who holds the claims, and where activity has gone quiet
The ranked leaders show a mix of academic institutions and biotech companies; recent-year momentum figures suggest even the top filers have slowed, consistent with the field-wide plateau after 2020.
A single academic-affiliated leader tops the ranking
The top-ranked assignee holds 28 of the 166 records in scope, well ahead of fifth place at 7. That gap between first and fifth is the clearest sign of concentration in this dataset.
The gap narrows quickly after the leader
Fifth place holds 7 records and tenth place 6 — a narrow spread that indicates a genuine mid-tier of active filers rather than a sharp cliff after the top one or two names.
Even leading filers show no recent-year activity
Several of the most active historical assignees show zero filings in the latest year, including one with a -100% year-on-year change. Given publication lag, this likely overstates any real slowdown, but it is consistent with the plateau visible in the aggregate trend.
| Assignee | Recent year | YoY |
|---|---|---|
| Dana-Farber Cancer Institute, Inc. | 0 | — |
| Captor Therapeutics S.A. | 0 | -100% |
| C4 Therapeutics, Inc. | 0 | — |
| Ribon Therapeutics, Inc. | 0 | — |
| Yale University | 0 | — |
| The Regents of the University of Michigan | 0 | — |
| Korea Institute of Science and Technology | 0 | — |
| Baylor College of Medicine | 0 | -100% |
Where to take this next
The dataset points to specific follow-up questions depending on whether the goal is freedom-to-operate, licensing, or identifying open claim space.
Check freedom-to-operate against the leading cohort
With 43.4% of records held by five assignees, any new filing in core E3 recruitment or ternary complex chemistry should be checked against that group's claim scope first, not just the most-cited individual patents.
Run a freedom-to-operate check in EurekaMap the under-claimed IPC branches in detail
Steroid-scaffold, peptide-based and acyclic linker chemistries each carry single-digit-percentage shares of the 166 records. A closer read of those subclasses can surface claim language that has not been tested against the dominant A61K/C07D filings.
Explore white space in EurekaWatch for renewed filing activity post-lag
Because publication lags filing by roughly 18 months, the apparent 2020 peak and subsequent plateau should be re-checked as later years fill in, particularly for assignees currently showing zero recent-year filings.
Track filing trends in EurekaCommon questions about PROTAC patents
Within this 166-record dataset, one assignee leads with 28 records, well ahead of the fifth-ranked entity at 7. The top five combined account for 43.4% of all records in scope, so the field is concentrated at the top even though 72 companies appear in the full ranking. That said, publication lag means the most recent filings by any assignee, including the leader, are undercounted in current figures.
No — filing peaked at 32 records in 2020 and has not returned to that level since, with the 2022 midpoint at 24. This looks like a plateau rather than continued growth, though the very latest year in any dataset is always partial because publication trails filing by around 18 months. A practitioner should treat the recent-year numbers as a floor, not a ceiling, on actual filing activity.
The dataset is filtered to A61K31 (medicinal preparations), C07D401 (heterocyclic compounds) and A61P35 (therapeutic activity against tumours), and within it A61K appears on 87.3% of records and C07D on 75.3%. Smaller but meaningful shares fall in C07J (steroids, 9.6%) and C07K (peptides and proteins, 4.8%), which is where degrader chemistry structurally diverges from the small-molecule mainstream. A single filing can carry multiple IPC classes, so these percentages overlap rather than sum to 100%.
The clearest under-claimed branches by record share are steroid-scaffold E3 ligase warheads, peptide-based degrader binding units, acyclic and carbocyclic linker chemistries, and genetically engineered degron systems — each sitting in the single digits of the 166-record total. These are not untouched, but they carry far fewer filings than the dominant heterocyclic small-molecule degrader chemistry, which is where a first claim with narrower, more specific scope has more room to stand.
That filing claims a specific PROTAC architecture — an Aurora A-kinase binder joined via an alkyl or polyalkyl ether linker to a thalidomide-family E3 ligase binder (thalidomide, lenalidomide, pomalidomide or apremilast) — so it constrains that particular combination of target, linker chemistry and cereblon-recruiting warhead rather than PROTAC design generally. Designs using different E3 ligases, different linker chemistries, or targets other than Aurora A-kinase sit outside its literal claim scope. A proper freedom-to-operate assessment still needs to check the claims against the specific target and warhead combination in question rather than relying on this summary alone.
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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.
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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.