Bioconjugation & PEGylation Patents: Leaders, Trends & Gaps 2026
- Filing has cooled since 2020. the peak year at 27 filings, with the 2026 count still partial and the mid-2022 figure of 16 showing a flat-to-declining trend rather than renewed growth.
- The top of the field is not fully consolidated. the leading assignee holds 32 records but the top 5 combined account for only 18.9% of all 571 records in scope, and the top 10 for 32.9% — a long tail does most of the filing.
- Claim density sits overwhelmingly in two IPC subclasses. A61K medicinal preparations (78.1%) and C07K peptides & proteins (65.3%) dominate, while condensation polymer chemistry under C08G covers only 8.6% of records.
What this landscape covers
This dataset tracks 571 published patent records filed between 2015 and mid-2026 that combine bioconjugation, PEGylation, or protein conjugation chemistry with claim language on site selectivity, conjugate heterogeneity, half-life extension, immunogenicity, or click chemistry, restricted to the core IPC groups for medicinal preparations, peptides and condensation polymers. It is a chemistry-and-formulation view of the field rather than a pure polymer-science one: the IPC gate pulls in therapeutic delivery and analytical claims alongside the underlying conjugation reactions themselves.
Because publication lags filing by roughly 18 months, the 2025 and 2026 counts in the trend chart are necessarily incomplete and should not be read as a real drop-off yet. The more reliable signal is the plateau visible from 2020 onward, well before the most recent two years enter the picture.
Filing trend and technology composition
Two views of the same 571-record set: how filing volume has moved year over year, and which IPC subclasses carry the claim weight.
Filing trend, 2017–2026
Filings ran at 16 in 2017, rose to a peak of 27 in 2020, and sat at 16 again by the 2022 midpoint — a pattern of growth followed by plateau rather than sustained expansion. The 2026 figure of 1 reflects the data cut-off, not a collapse in filing activity.
IPC subclass composition
A61K (78.1% of records) and C07K (65.3%) anchor the field as expected for a therapeutics-oriented conjugation corpus. A61P therapeutic-activity claims reach 28.9%, C12N genetic engineering 18.7%, and G01N analytical claims 9.3% — smaller but persistent slices that mark where conjugation chemistry intersects with characterization and biologics manufacture. Condensation polymer claims under C08G, at 8.6%, are comparatively thin given how central PEG chemistry is to the topic, which is one indicator of where claim space remains open.
Shares are the percentage of the 571 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Bioconjugation and PEGylation Chemistry with Eureka
This page is one run against one query. Ask Eureka your own question about bioconjugation and pegylation chemistry and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records
Bioconjugation Methods for Targeted in Situ Therapeutic Delivery (US20200038484A1)
Bioconjugation methods for promoting wound healing are disclosed. In particular, the invention relates to the in situ application of non-photochemical crosslinking techniques such as copper-free click chemistry using strain-promoted azide-alkyne cycloaddition (SPAAC) or multi-functional succinimidyl esters as a therapeutic delivery modality for biomolecules and stem cells to enhance wound healing.Filed by Stanford, this record ties bioorthogonal click chemistry directly to an in situ delivery use case rather than to protein pharmacokinetics alone.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO1992016221A1 | Pegylation of polypeptides | 1,097 |
| 2 | US6737236B1 | Bioconjugation of macromolecules | 545 |
| 3 | US6420339B1 | Site-directed dual pegylation of proteins for improved bioactivity and biocompatibility | 479 |
| 4 | US20050114037A1 | Methods for rational pegylation of proteins | 448 |
| 5 | WO1995034326A1 | Pegylation reagents and compounds formed therewith | 446 |
| 6 | WO2009155258A2 | Glucagon/GLP-1 receptor co-agonists | 426 |
| 7 | WO1998048837A1 | Polyalkylene oxide-modified single chain polypeptides | 400 |
| 8 | US7427678B2 | Method for immobilizing oligonucleotides employing the cycloaddition bioconjugation method | 356 |
| 9 | WO1999055377A2 | Polyol-IFN-beta conjugates | 331 |
| 10 | WO2004009627A1 | Pegylated erythropoietic compounds | 324 |
Citation counts inside a searched corpus favour older filings; treat these as markers of foundational influence rather than of current filing activity.
Each row carries its publication number; clicking a row searches Eureka by that number.
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What the filing counts, citation pattern and IPC spread mean for a team deciding where to file next.
No single assignee dominates the field
The leading assignee holds 32 records out of 571, and the top 5 combined reach only 18.9% of records in scope. That leaves the bulk of filing activity spread across a long tail of single- and few-filing entrants, which is unusual for a therapeutics-adjacent chemistry field this mature.
Filing has plateaued since the 2020 peak
Volume climbed from 16 filings in 2017 to a peak of 27 in 2020, then returned to 16 by the 2022 midpoint. Several of the most active historical assignees show zero filings in the latest tracked year, consistent with a field that has moved past its initial land-grab phase.
Foundational PEGylation patents still anchor the field
The most-cited record, a 1992 filing on pegylation of polypeptides, carries 1,097 citations, and the next four most-cited records are all pre-2005 filings on conjugation chemistry and rational pegylation. New filers work in the shadow of this prior art regardless of how novel their specific conjugation chemistry is.
Polymer-chemistry claims are thinner than the topic implies
Despite PEGylation being named in the search itself, condensation-polymer claims under C08G cover only 8.6% of records, well behind A61K (78.1%) and C07K (65.3%). Most filers claim the therapeutic composition or the peptide construct, leaving the polymer synthesis chemistry itself comparatively under-litigated in claim language.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to bioconjugation and pegylation chemistry, with the prior art for and against each one.
Who is filing, and where the gate sits
The ranked leaders sit at the top of a long tail; recent-year momentum has cooled across nearly every one of the most active historical filers.
A single leader without a wide gap to the field
The top-ranked assignee holds 32 records, ahead of a fifth-place holder at 18 and a tenth-place holder at 13. The gradient is gentle rather than a cliff, meaning displacement at the top is plausible for a well-resourced new entrant.
Co-filing is limited but concentrated where it exists
Only 10 co-assignee pairs appear across the corpus, and the strongest pair files jointly 17 times — far ahead of the next pairs at 4 and 3. Most assignees in this field file solo rather than through joint ventures or research partnerships.
Recent-year activity has gone quiet among historical leaders
Several of the assignees with the deepest historical portfolios recorded zero filings in the latest tracked year, and at least two show a full -100% year-on-year change. That does not mean the underlying science has stalled, but it does mean the active filers of 2026 may not be the names that built this landscape.
| Assignee | Recent year | YoY |
|---|---|---|
| Biogen MA Inc. | 0 | — |
| Amgen Inc. | 0 | — |
| Applied Research Systems ARS Holding N.V. | 0 | — |
| ABTIS Co., Ltd. | 0 | -100% |
| Research & Business Foundation Sungkyunkwan University | 0 | -100% |
| IBC Pharmaceuticals Inc. | 0 | — |
| Merck Sharp & Dohme Corp. | 0 | — |
| Merck Serono SA | 0 | — |
Where to take this analysis
The landscape numbers point to specific next steps depending on whether the goal is freedom-to-operate, portfolio strategy, or scouting.
Check freedom-to-operate against the most-cited prior art
The five most-cited records, several dating to the 1990s and early 2000s, still shape claim scope in pegylation reagent and site-directed conjugation chemistry. Any new filing in this space should be checked against them before drafting claims.
Run a freedom-to-operate searchTrack momentum shifts among historical leaders
With several top historical assignees at zero filings in the latest year, the competitive set active in 2026 may differ from the one that built the current portfolio base. Monitoring new entrants matters more here than tracking incumbents.
Set up assignee monitoringProbe the under-claimed polymer-chemistry branch
C08G condensation-polymer claims cover just 8.6% of records despite PEG chemistry being central to the field's name. A first-claim drafted around novel polymer backbone synthesis rather than the therapeutic composition may face less prior art congestion.
Explore white space with EurekaCommon questions about this landscape
The ranked leaders in this dataset span pharmaceutical companies, university technology-transfer offices and specialty conjugation-chemistry firms, with the top assignee holding 32 records out of 571 in scope. No single company dominates the field: the top 5 assignees combined account for only 18.9% of all records, and the top 10 for 32.9%, which points to a fragmented competitive landscape rather than one controlled by a handful of players. Anyone assessing freedom-to-operate should look beyond the top few names to the long tail of single- and few-filing entrants, since a meaningful share of the claim space sits there.
Filing activity peaked at 27 records in 2020 and had returned to 16 by the 2022 midpoint, indicating a plateau rather than continued growth. The 2026 figure appears much lower, but that reflects the roughly 18-month lag between filing and publication rather than an actual drop in research activity. Readers should treat the most recent one to two years of any patent trend as understated and wait for later data before concluding the field has genuinely slowed.
The bulk of records fall under A61K (medicinal preparations, 78.1% of the 571 records in scope) and C07K (peptides and proteins, 65.3%), reflecting the field's orientation toward therapeutic applications. A61P (therapeutic activity, 28.9%) and C12N (microorganisms and genetic engineering, 18.7%) appear as secondary but persistent classes. Condensation-polymer claims under C08G, which cover the PEG synthesis chemistry itself, are comparatively thin at 8.6%, suggesting that most patent protection targets the therapeutic construct rather than the underlying polymer chemistry.
The most-cited record in this dataset is a 1992 filing on pegylation of polypeptides with 1,097 citations, followed by patents on macromolecule bioconjugation, site-directed dual pegylation, and rational pegylation methods, several of which carry over 400 citations each. These older filings still anchor the field's prior art baseline even though citation counts inside any searched corpus tend to favour older records simply by virtue of having had more time to accumulate them. A freedom-to-operate review for new site-selective or half-life-extension conjugation chemistry should start with this set before moving to more recent filings.
The clearest gap sits in condensation-polymer synthesis chemistry under C08G, which covers only 8.6% of the 571 records despite PEG chemistry being central to the field. Bioorthogonal click-chemistry approaches for in situ delivery, enzymatic site-specific conjugation catalysts, and non-PEG half-life-extension carriers also appear thinly represented relative to the dominant A61K and C07K claim categories. These branches are good candidates for a first claim precisely because the dominant assignees have concentrated their filing elsewhere.
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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.