The disease biology driving the DMOAD gap

Knee osteoarthritis carries a 45% lifetime risk of symptomatic disease and, as of the date of this analysis, no approved disease-modifying osteoarthritis drug (DMOAD) exists. This unmet need is the engine behind a rapid expansion of patent filings across multiple mechanistic fronts, each targeting a distinct node in the pathological cascade that destroys cartilage, inflames synovium, and remodels subchondral bone.

Retrieved patent filings consistently identify IL-1β as the central driver of chondrocyte catabolism in the OA joint. A Novartis patent filing describes how “excess pro-inflammatory cytokines (e.g., IL-1β, TNFα) and chemokines drive intraarticular inflammation… downregulate cartilage matrix production and increase matrix-degrading enzyme (MMP, ADAMTS) production” in OA synovium, cartilage, and synovial fluid. Beyond IL-1β, the molecular target landscape is broad: ADAMTS4 and ADAMTS5 aggrecanases, MMP-3 and MMP-13, IL-6, IL-17A, TNFα, oncostatin M (OSM), and upstream regulators including the NLRP3 inflammasome, JAK/STAT pathway, PI3K/PKB, and the aryl hydrocarbon receptor (AHR).

According to WHO, osteoarthritis is among the leading causes of disability globally, and the pipeline activity documented here reflects the scale of commercial and academic investment in finally closing the DMOAD gap. The three most patent-active therapeutic dimensions in this dataset are GLP-1 receptor agonism, IL-1 axis inhibition, and intraarticular delivery platform innovation — each examined in turn below.

GLP-1 receptor agonists: from metabolic drug to joint therapy

GLP-1 receptor agonists represent the most novel emerging modality for knee OA in this dataset, with multiple independent groups pursuing liraglutide and semaglutide reformulated specifically for intraarticular injection. In the joint context, GLP-1R agonism is posited to reduce pro-inflammatory cytokine secretion — including IL-1β — in chondrocytes and synoviocytes, stimulate anabolic pathways for cartilage matrix production, inhibit catabolic enzymes, and reduce MMP-driven proteoglycan loss.

Three French academic and hospital institutions have filed patents covering this approach. INSERM’s 2022 Canadian patent covers liraglutide and semaglutide formulated with tromethamine or phosphate buffer and isotonic agents — including glucose, PEG, and glycerol — for intraarticular administration in joint disease including OA. The same filing contemplates combination with GIP (glucose-dependent insulinotropic polypeptide) and FGF-18. Assistance Publique-Hôpitaux de Paris filed a 2024 CN patent describing GLP-1R agonist intraarticular formulations targeting OA-associated inflammation and anti-degradation mechanisms. Sorbonne University’s 2021 CN patent explicitly claims that GLP-1 and GLP-1 analogs induce chondrocyte anabolic stimulation, reduce catabolism, and cover cartilage regeneration and stem cell differentiation to chondrocytes.

“Retrieved data from three independent European groups and a South Korean biotech demonstrate convergent interest in GLP-1R agonism — both as intraarticular reformulations of approved systemic agents and as novel fusion proteins — creating near-term IP freedom-to-operate questions for any entrant in this space.”

An innovative fusion protein strategy extends this further. ImmunoForge Co., Ltd. (South Korea) has filed a 2023 Japanese patent describing a bispecific fusion protein combining a GLP-1R agonist with an anti-OSCAR (Osteoclast-Associated Receptor) antibody, reported to have “excellent chondroprotective and pain-relieving effects” validated in arthritis models. This positions GLP-1R as a platform for bispecific engineering, not merely a repurposed metabolic drug. No approved GLP-1R-based agent for OA has been identified in this dataset; the modality sits at the preclinical-to-early-clinical signal stage.

IL-1 axis inhibitors: dual blockade and NLRP3 upstream targeting

IL-1 inhibition is the most heavily represented cytokine-targeting modality for knee OA across the retrieved patent dataset, with two mechanistic sub-classes: direct dual IL-1α/β blockade via bispecific DVD-Ig antibodies, and upstream NLRP3 inflammasome inhibition that prevents IL-1β maturation before it can drive cartilage destruction.

AbbVie ABT-981: Dual Variable Domain IL-1α/β Blockade

AbbVie’s ABT-981 is a Dual Variable Domain Immunoglobulin (DVD-Ig) binding protein that simultaneously neutralises both IL-1α and IL-1β. Retrieved patent documents contain clinical dosing data from knee OA patients receiving 0.3, 1, or 3 mg/kg doses every other week, with MMP-generated type III collagen fragment (C3M) and CRP measured as pharmacodynamic markers. AbbVie has prosecuted this asset across EP, CA, AU, JP, and HK jurisdictions, indicating a coordinated global IP strategy. According to EMA guidance on biologic development, multi-jurisdictional filing patterns of this scope typically reflect late-stage clinical or near-approval programs.

Novartis NLRP3 Inhibitor: Upstream Inflammasome Targeting

Novartis has filed patents disclosing NLRP3 inhibitors for OA, positioning them explicitly as potential DMOADs. The filings state that “NLRP3 inhibitors block IL-1β secretion, IL-18 secretion and pyroptotic cell death in vitro and in vivo in response to a variety of NLRP3-dependent danger signals,” and the dosing regimen patent covers NLRP3 inhibitor monotherapy or combination with at least one other therapeutic agent. The stated clinical goal is to “reduce pain, slow joint damage and improve function” in symptomatic OA adults. This upstream approach differs mechanistically from ABT-981: rather than neutralising secreted IL-1β protein, NLRP3 inhibition prevents its maturation and release, potentially offering broader anti-inflammatory coverage including IL-18 suppression.

Beyond AbbVie and Novartis, the IL-1 signalling pathway is being targeted at additional nodes. Genzyme Corporation has filed a Japanese patent describing JAK3 inhibitors that prevent IL-1-induced gene expression in chondrocytes with in vivo efficacy in OA cartilage degradation models. Elanco Animal Health’s 2024–2025 WO and AU filings cover IRAK4 (Interleukin-1 receptor-associated kinase 4) inhibitors for OA pain and inflammation, primarily targeting canine OA but with claims extending to mammalian OA broadly. These represent recent entries of upstream IL-1 signalling pathway inhibitors into the OA space, benchmarked against the ABT-981 clinical biomarker dataset (C3M, CRP dose-response).

Intraarticular delivery platforms: biologics, particles, and small molecules

Intraarticular (IA) injection is the dominant delivery modality across the retrieved dataset for knee OA, enabling local high drug concentration while minimising systemic exposure. The platform diversity is striking: biologics, polymer microparticles, small molecules, peptides, and repurposed systemic drugs are all being adapted for joint-specific administration.

Novartis Compound 1 (ANGPTL3 Polypeptide) — Most Advanced Biologic Signal

The most clinically advanced intraarticular biologic signal in this dataset is Novartis Compound 1, a modified ANGPTL3 polypeptide (SEQ ID NO:17) with chondrogenic activity. It has been administered intraarticularly in a randomised, double-blind, first-in-human single ascending dose study in primary OA patients scheduled for total knee replacement, at doses of 0.2–60 mg IA. Patent text references a “clear dose-response pattern… long-term pharmacodynamic effects… good safety profile in human subjects.” An interim analysis of a proof-of-concept study Part B in mild-to-moderate knee OA patients receiving 4 monthly injections of 20 mg or 40 mg is noted as ongoing, with a 6-month dosing cycle comprising 3 monthly IA injections described in a 2024 Japanese filing. Novartis also claims IA co-injection of Compound 1 with an anti-IL-1β antibody, combining chondrogenic and anti-inflammatory mechanisms in a single combination regimen.

ADAMTS5 Inhibitory Polypeptide — Merck Patent GmbH

Merck Patent GmbH has filed a 2023 CN patent providing dosing regimens for ADAMTS5 inhibitory polypeptides in knee OA. ADAMTS5 (aggrecanase-5) drives proteoglycan (aggrecan) degradation, a hallmark of early irreversible cartilage loss. This biologic DMOAD candidate targets the catabolic enzyme directly, distinct from cytokine-blocking approaches. Earlier ADAMTS5 small molecule aggrecanase inhibitor filings in the ES jurisdiction (now inactive) indicate a long-running program that has shifted toward polypeptide modalities.

Immunomodulatory PLGA Microparticles — University of California

The University of California Board of Regents describes IA injection of all-trans retinoic acid (ATRA)-encapsulated PLGA microparticles that produce both local and contralateral (systemic) disease modification in SKG mouse arthritis models via regulatory T cell (Treg) induction. This approach is mechanistically distinct from conventional corticosteroid or hyaluronic acid IA injections and signals an emerging direction for locally injectable, Treg-inducing immunotherapy with systemic reach.

Intraarticular Metformin — Indiana University (2025)

Indiana University’s 2025 WO filing discloses intraarticular metformin as a potential preventive strategy for post-traumatic osteoarthritis, extending the AMPK-activating drug into a new delivery modality. This represents one of the most recent entries in the IA delivery patent space and illustrates the breadth of repurposing strategies now being explored.

Platelet-Rich Plasma (PRP) — Dual Injection Protocol

A clinical paper from Hospital Vithas San Jose (Spain) reports a novel dual-injection protocol combining intraarticular PRP with intraosseous PRP infiltrations into subchondral bone. KOOS pain scores improved significantly from 61.55±14.11 at baseline to 74.60±19.19 at 24 weeks (p=0.008), with mesenchymal stem cell quantification in synovial fluid as an additional outcome measure. Intraarticular hyaluronic acid remains in clinical use as a standard-of-care IA option, with a favourable safety profile compared to NSAIDs for long-term knee OA management, as reported by TRB Chemedica International SA in a 2017 clinical paper.

Clinical translation signals and combination strategies

Several assets in the retrieved dataset have crossed from preclinical into human dosing, providing benchmarks against which newer entrants can be evaluated. The clinical evidence embedded in patent filings — rather than trial registries — is a distinctive feature of this pipeline snapshot.

Novartis Compound 1 (ANGPTL3 polypeptide) has the most advanced clinical signal: a completed randomised, double-blind, placebo-controlled, single ascending dose study in primary OA patients scheduled for total knee replacement, with an ongoing proof-of-concept Part B study in mild-to-moderate knee OA patients receiving 4 monthly injections of 20 mg or 40 mg. AbbVie ABT-981 has Phase 2-level clinical evidence in knee OA, with dose-ranging data (0.3, 1, and 3 mg/kg every other week) and C3M and CRP pharmacodynamic readouts documented across multiple jurisdictions. Regeneron’s anti-NGF antibody fasinumab is described in a US and WO patent context for treating knee and hip OA pain in patients non-responsive or intolerant to standard analgesic therapy, with arthropathy safety monitoring as a regulatory concern. According to FDA guidance on analgesic drug development for OA, arthropathy risk is a recognised safety signal for anti-NGF agents.

Combination strategies are a defining feature of the most advanced programs. Novartis explicitly claims IA co-injection of Compound 1 with anti-IL-1β antibody, combining chondrogenic and anti-inflammatory mechanisms. INSERM’s Canadian patent contemplates combination of GLP-1R agonists with GIP, FGF-18, anti-NGF agents, and Wnt pathway modulators. Novartis’ NLRP3 dosing patent explicitly covers combination with “at least one other therapeutic agent.” The corticosteroid plus P-glycoprotein inhibitor IA combination (Xiangya Hospital, Central South University, 2024) positions efflux pump inhibition as a strategy to extend corticosteroid joint retention and prolong analgesia.

University Health Network’s 2024 WO filing for a cell-based anti-inflammatory treatment in knee OA includes a phenotype/endotype patient selection framework — signalling that precision patient stratification by synovial fluid molecular endotype, imaging, and biomarker profiles is increasingly being codified into patent claims. This suggests future DMOAD trials will require enrichment strategies to demonstrate structural modification activity.

Strategic implications for IP and competitive positioning

The patent landscape reviewed here carries several actionable implications for R&D leaders, IP counsel, and business development teams operating in the musculoskeletal space.

GLP-1R agonists create immediate freedom-to-operate questions. The convergence of INSERM, Sorbonne University, Assistance Publique-Hôpitaux de Paris, and ImmunoForge on GLP-1R agonism for knee OA — across CA, CN, JP, and BR jurisdictions — means any new entrant formulating semaglutide or liraglutide for intraarticular use must conduct a thorough FTO analysis before entering clinical development. The fusion protein approach (GLP-1R agonist + anti-OSCAR antibody) from ImmunoForge adds a bispecific engineering dimension that may be independently patentable.

Novartis holds the broadest claimed DMOAD portfolio in this dataset. The combination of first-in-human clinical data for ANGPTL3 IA therapy, NLRP3 inhibitor dosing regimens, and anti-IL-1β IA combinations positions Novartis with the widest claimed therapeutic portfolio for structural KOA modification. Competitors should monitor prosecution outcomes across CN, JP, and EP families closely, particularly claim scope for IA dosing regimens and combination claims.

AbbVie ABT-981 provides the clinical comparator benchmark for IL-1 pathway entrants. The C3M and CRP dose-response data embedded in ABT-981 filings across multiple jurisdictions constitute a de facto comparator dataset for evaluating NLRP3 inhibitors, IRAK4 inhibitors, and other IL-1 pathway modifiers. New entrants should design biomarker strategies that enable direct comparison with this benchmark.

Intraarticular delivery formulation IP is expanding rapidly. Multiple assignees — Novartis, INSERM, Orthotrophix, University of California, Indiana University — are filing IA-specific formulation and dosing patents, suggesting that delivery platform IP, not just molecular target IP, will be a critical competitive differentiator. Gel depots, polymer microparticles, and sustained-release carriers are emerging as independently patentable assets. The WIPO Patent Cooperation Treaty filing patterns across these assignees indicate active global prosecution intent for delivery platform claims.

“Delivery platform IP — not just molecular target IP — will be a critical competitive differentiator; gel depots, polymer microparticles, and sustained-release carriers are emerging as independently patentable assets in the knee OA intraarticular space.”

Patient stratification is becoming a prerequisite for clinical success. University Health Network’s 2024 WO filing for cell-based IA therapy and the broader trend toward endotype-specific patient selection signal that future DMOAD trials will need enrichment strategies — defined by synovial fluid molecular endotype, imaging, and biomarker profiles — to demonstrate structural modification activity. Teams that codify patient selection criteria into their patent claims early may gain both IP and regulatory advantages.