Imlifidase & IgG-Cleaving Enzymes — PatSnap Eureka
Imlifidase & IgG-Cleaving Enzyme Pipeline in Kidney Transplant Desensitization
Approximately 20–30% of US kidney transplant waitlist candidates are HLA-sensitized, facing prolonged wait times and elevated antibody-mediated rejection risk. IgG-cleaving enzymes such as imlifidase (IdeS) offer a mechanistically distinct approach to rapidly neutralizing donor-specific antibodies before and after transplantation.
The Immunological Barrier to Kidney Transplantation
Antibody-mediated rejection (AMR) is the primary driver of long-term allograft failure. The central barrier is the presence of pre-formed or de novo donor-specific antibodies (DSAs) directed against human leukocyte antigens (HLA) expressed on the vascular endothelium and tubular cells of transplanted kidneys. DSA binding activates the classical complement cascade, culminating in endothelial injury, transplant glomerulopathy (TG), and chronic active ABMR (cABMR).
Life sciences patent intelligence from PatSnap Eureka identifies IL-6 as a pivotal cytokine sustaining DSA-producing plasma cells and driving allograft inflammation. Multiple patent families from Cedars-Sinai Medical Center explicitly frame IL-6 as the molecular driver of sensitization and AMR pathobiology, with clazakizumab (an anti-IL-6 antibody) demonstrating reduced DSA levels in HLA-sensitized patients awaiting kidney transplant.
Complement component C5 is identified as a downstream effector target. The terminal complement membrane attack complex (MAC), generated after C5 cleavage, mediates acute endothelial damage. Anti-C5 antibody strategies are specifically claimed to reduce AMR in sensitized recipients receiving phased post-reperfusion dosing. The classical complement pathway initiator C1 is addressed separately: C1 esterase inhibitor (C1-INH) blocks both the classical and lectin complement pathways at a more proximal level, with patent filings from Shire ViroPharma Incorporated and Cedars-Sinai Medical Center claiming long-term eGFR improvement after kidney transplant.
A mechanistically distinct IgG-level target is introduced by patent analysis of Hansa BioPharma AB through the IdeS (Imlifidase/IgG cysteine protease) enzyme, which cleaves IgG at the hinge region, eliminating both Fc-receptor binding and complement fixation. CD38-expressing plasma cells are identified as a cellular source of pathogenic DSA, with Cedars-Sinai Medical Center patenting anti-CD38 antibody methods (including daratumumab) as a desensitization strategy for patients refractory to standard-of-care plasmapheresis and IVIG.
Five Mechanistic Approaches to Desensitization & AMR
Retrieved patent and literature data identify five principal therapeutic classes, each targeting a distinct point in the DSA-mediated rejection cascade.
IgG-Cleaving Enzyme Therapy (Imlifidase / IdeS)
IdeS (Imlifidase), a streptococcal cysteine protease, cleaves human IgG at the lower hinge region, generating F(ab')₂ and Fc fragments. This eliminates Fc-receptor-mediated effector functions, complement fixation via C1q, and ADCC. Hansa Biopharma's method patent specifies administration no longer than 6 hours before transplantation at 0.01–1 mg/kg body weight. AstraZeneca's 2024 patent on improved IgG-degrading cysteine proteases extends claims to gene therapy re-dosing applications, with effective doses of 0.05–0.50 mg/kg.
Hansa Biopharma AB · AstraZeneca 2024Anti-IL-6 Antibody Therapy (Clazakizumab)
IL-6 promotes plasma cell survival, DSA production, and allograft inflammation. Clazakizumab, an anti-IL-6 antibody, blocks IL-6 signaling, reducing both circulating DSA and inflammatory markers of cABMR. Cedars-Sinai Medical Center has filed clazakizumab-based patents in US, WO, CA, AU, BR, JP, and CN jurisdictions, with prosecution active as recently as 2025. Biopsy-proven cABMR patients showed stabilized eGFR at 6, 12, and 18 months post-treatment.
Cedars-Sinai · Vitaeris Corp. · 10+ patent familiesComplement Pathway Inhibitors (Anti-C5 & C1-INH)
Alexion Pharmaceuticals holds patents on phased post-reperfusion anti-C5 dosing in sensitized recipients who have received ≥2 weeks of desensitization therapy, with only 1/16 (6%) developing acute AMR versus ~40% of historical controls. C1 esterase inhibitor (C1-INH) addresses the more proximal classical/lectin pathway; a Cedars-Sinai study showed significantly reduced dialysis requirements at weeks 2 and 4, and improved eGFR at 1 year post-transplant.
Alexion · Shire ViroPharma · CSL BehringAnti-CD38 Plasma Cell Depletion (Daratumumab)
CD38 is highly expressed on long-lived plasma cells producing DSA. Anti-CD38 antibodies such as daratumumab deplete this cellular DSA source, providing a complementary mechanism to DSA-clearance strategies. Cedars-Sinai's US patent positions anti-CD38 therapy specifically for patients refractory to IVIG and plasmapheresis, representing an escalation strategy for drug-resistant sensitization. This remains an underexplored white space with only one retrieved patent assignee active in this indication.
Cedars-Sinai Medical Center · 2022 PatentKey Efficacy & Activity Signals from Retrieved Data
Quantitative signals extracted from patent specifications and referenced clinical data within the retrieved dataset.
Acute AMR Incidence: Anti-C5 vs Historical Controls
Only 1/16 (6%) of sensitized recipients receiving anti-C5 antibody developed acute AMR at 1 month versus ~40% of historical controls, per retrieved Alexion patent data.
Patent Activity by Assignee: Desensitization & AMR Space
Cedars-Sinai Medical Center dominates with 15+ patent families; Hansa Biopharma holds the exclusive IgG-cleaving enzyme position in the retrieved dataset.
DSA-IgG3 Reduction: Imlifidase + EndoS Combination
Hansa Biopharma's conditioning regimen patent discloses ~80% DSA-IgG3 reduction in sensitized mouse models with the imlifidase + EndoS dual-mechanism combination.
Standard Desensitization Protocol: Treatment Intensity
A clinical paper reports 32 HLA-incompatible live-donor recipients undergoing a multi-component desensitization protocol, with a mean of 8±3 plasmapheresis/immunoadsorption sessions.
Next-Generation Combination Protocols
Retrieved results signal several combination strategies as active development directions, addressing the limitations of single-agent approaches.
Imlifidase + EndoS Dual Enzyme
The Hansa Biopharma conditioning regimen patent explicitly discloses the rationale for combining IdeS (cleaves IgG, especially IgG3) with EndoS (deglycosylates Fc of imlifidase-resistant IgG molecules), producing dual-mechanism IgG effector silencing. This combination addresses incomplete DSA elimination by either enzyme alone.
Anti-IL-6 + IVIG + Plasmapheresis ± Rituximab
Multiple Cedars-Sinai patent families describe clazakizumab administered simultaneously or sequentially with IVIG, plasmapheresis, and anti-CD20 agents. The molecular rationale is that plasmapheresis and IVIG remove circulating DSA acutely, while clazakizumab suppresses IL-6-driven plasma cell survival and DSA re-synthesis.
Who Holds the Key IP Positions?
Patent activity is concentrated among US academic medical centers and a small number of biopharmaceutical companies, with distinct IP positions by modality.
| Assignee | Primary Modality | Key Claims | Jurisdictions | Latest Filing |
|---|---|---|---|---|
| Cedars-Sinai Medical Center Most Active | Anti-IL-6 (Clazakizumab), Anti-CD38, C1-INH, CTLA4-Ig | Pre-transplant desensitization, cABMR treatment, eGFR stabilization at 6–18 months | US, WO, CA, AU, BR, JP, CN | 2025 |
| Hansa Biopharma AB | IgG-Cleaving Enzyme (IdeS/Imlifidase) | IdeS + EndoS conditioning, ≤6hr pre-transplant dosing, IgG cysteine protease product class | JP, NZ, CL, CN | 2024 |
| AstraZeneca (Ireland) Ltd. | Improved IgG-Degrading Cysteine Proteases | Transplant desensitization (cPRA ≥10%), gene therapy re-dosing, 0.05–0.50 mg/kg dose range | CN | 2024 |
| Alexion Pharmaceuticals | Anti-C5 Antibody | Phased post-reperfusion dosing, ≥2 weeks pre-desensitization requirement | WO, US, JP, EP | 2018 |
| Shire ViroPharma / CSL Behring | C1 Esterase Inhibitor (C1-INH) | Classical/lectin complement blockade, subcutaneous maintenance ≥10 weeks, improved 1-year eGFR | US, EP, JP, HK | 2023 |
| Vitaeris Corp. | Anti-IL-6 (Clazakizumab) | Solid organ transplant desensitization and ABMR prevention/stabilization across kidney, heart, liver, lung, pancreas, intestine | WO, JP | 2019 |
Track IP Movements Across All Assignees
PatSnap Eureka monitors new filings, prosecution updates, and citation networks in real time.
What the Patent Landscape Signals for Developers & IP Strategists
Hansa Biopharma and AstraZeneca hold the primary IgG-cleaving enzyme IP positions in this dataset: Hansa controls the foundational IdeS/imlifidase transplant conditioning claims, while AstraZeneca's 2024 filing on improved cysteine proteases introduces competition at the enzyme engineering level and extends the platform to gene therapy, creating a potential IP encroachment dynamic that Hansa will need to monitor. Both companies' activities are tracked through PatSnap's patent analytics platform.
Cedars-Sinai Medical Center has constructed a remarkably broad desensitization and AMR treatment IP portfolio centered on clazakizumab (anti-IL-6), with prosecution active across US, WO, CA, AU, BR, JP, and CN jurisdictions as recently as 2025. Drug developers and IP strategists should note that both pre-transplant desensitization and post-transplant cABMR treatment indications are claimed, covering the full clinical timeline of sensitization management. Relevant context on transplant immunology can be found through WIPO's patent database.
No single modality in the retrieved dataset provides durable protection against both acute AMR and long-term transplant glomerulopathy. Retrieved clinical signals from anti-C5 antibody data (approximately 50% TG incidence after cessation) and the rebound of IgG after IdeS treatment both indicate that combination or sequential strategies are likely to define next-generation protocols. The NIH/NIDDK provides additional context on end-stage renal disease burden and transplant outcomes.
Anti-CD38 therapy (daratumumab) represents an underexplored but strategically positioned escalation option for standard-of-care refractory patients, with only one retrieved patent assignee (Cedars-Sinai) active in this space within the dataset. This represents a potential white space for biopharmaceutical developers with CD38-targeting assets in oncology seeking transplant label extensions. For life sciences R&D teams, this gap represents a significant opportunity.
The proximal complement pathway (C1-INH) may offer allograft survival benefits beyond AMR prevention, including ischemia-reperfusion injury mitigation in deceased-donor recipients, as signaled by Cedars-Sinai C1-INH data showing improved 1-year eGFR. The Transplantation Society maintains clinical guidance on complement-mediated rejection management.
Imlifidase & IgG-Cleaving Enzymes in Kidney Transplant — Key Questions Answered
IdeS (Imlifidase), a streptococcal cysteine protease, cleaves human IgG at the lower hinge region, generating F(ab')₂ and Fc fragments. This eliminates Fc-receptor-mediated effector functions, complement fixation via C1q, and antibody-dependent cellular cytotoxicity (ADCC). In sensitized recipients, this cleavage transiently but profoundly reduces functional DSA titers, enabling a crossmatch-negative window for transplantation.
Approximately 20–30% of waitlisted candidates in the United States are HLA-sensitized, facing dramatically prolonged wait times and elevated risks of antibody-mediated rejection (AMR).
IL-6 promotes plasma cell survival, DSA production, and allograft inflammation. IL-6 sustains B-cell differentiation into DSA-producing plasma cells and promotes the inflammatory milieu of the allograft. Clazakizumab (anti-IL-6) at subcutaneous doses of approximately 25 mg reduces DSA in HLA-sensitized patients and stabilizes eGFR in cABMR.
Retrieved data cite a study of 16 sensitized human kidney transplant recipients given anti-C5 monoclonal antibody after transplantation, in which only 1/16 (6%) developed acute AMR within the first month compared with approximately 40% of historical controls. However, nearly 50% of patients developed transplant glomerulopathy after cessation of therapy, consistent with historical controls, pointing to the limitation of terminal complement blockade alone.
The Hansa Biopharma conditioning regimen patent explicitly discloses the rationale for combining IdeS (cleaves IgG, especially IgG3) with EndoS (deglycosylates Fc of imlifidase-resistant IgG molecules), producing dual-mechanism IgG effector silencing. This combination addresses incomplete DSA elimination by either enzyme alone, with imlifidase preferentially cleaving DSA-IgG3 subclass (approximately 80% reduction in murine models).
CD38 is highly expressed on long-lived plasma cells producing DSA. Anti-CD38 antibodies such as daratumumab deplete this cellular DSA source. Cedars-Sinai Medical Center's US patent positions anti-CD38 therapy specifically for patients refractory to IVIG and plasmapheresis (drug-resistant sensitization), representing an escalation strategy in the desensitization cascade.
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References
- Transplant conditioning regimens — Hansa BioPharma AB, 2023, JP [Patent]
- Methods to enhance organ transplant and antibody therapies — Hansa Biopharma AB, 2024, NZ [Patent]
- IgG Cysteine Proteases — Hansa Biopharma AB, 2018, CL [Patent]
- A Method — Hansa Medical Corporation (Hansa BioPharma predecessor), 2017, CN [Patent]
- Improved IgG Degrading Enzyme and Methods of Use — AstraZeneca (Ireland) Ltd., 2024, CN [Patent]
- Use of clazakizumab to desensitize and improve renal transplantation in HLA-sensitized patients — Cedars-Sinai Medical Center, 2020, WO [Patent]
- Use of clazakizumab to desensitize and improve renal transplantation in HLA-sensitized patients — Cedars-Sinai Medical Center, 2021, US [Patent]
- Clazakizumab in the Treatment of Chronic Antibody-Mediated Rejection of Organ Transplant — Cedars-Sinai Medical Center, 2025, US [Patent]
- Clazakizumab in the treatment of chronic antibody-mediated rejection of organ transplant — Cedars-Sinai Medical Center [Patent]
- Efficacy of an Anti-C5 antibody in the prevention of antibody mediated rejection in sensitized recipients of a kidney transplant — Wang/Alexion Pharmaceuticals, 2018 [Patent]
- Efficacy of an Anti-C5 Antibody in the Prevention of Antibody Mediated Rejection in Sensitized Recipients of a Kidney Transplant — Alexion Pharmaceuticals, 2018 [Patent]
- Methods of treating antibody-mediated rejection in organ transplant patients with C1-esterase inhibitor — Shire ViroPharma, 2020 [Patent]
- Methods of treating antibody-mediated rejection in organ transplant patients with C1-esterase inhibitor — Shire ViroPharma, 2016 [Patent]
- Methods for improving organ function in organ transplant patients — Cedars-Sinai Medical Center, 2020 [Patent]
- Methods of treating antibody-mediated rejection — CSL Behring Germany (CSL Behring GmbH), 2023 [Patent]
- Anti-CD38 agents for desensitization and treatment of antibody-mediated rejection of organ transplants — Cedars-Sinai Medical Center, 2022 [Patent]
- Use of Anti-IL-6 Antibody for Desensitization of Solid Organ Transplant Recipients and/or for Preventing, Stabilizing or Reducing ABMR — Vitaeris Corp., 2019 [Patent]
- Type II Anti-CD20 Antibody for Use in Organ Transplantation — Genentech, Inc., 2018 [Patent]
- Kidney transplantation of 32 patients from HLA-incompatible live donors: Efficacy and outcome after desensitization — Servicio de Nefrología, Complexo Hospitalario Universitario A Coruña, 2017 [Paper]
- National Center for Biotechnology Information (NCBI) — HLA and transplant immunology literature
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) — End-stage renal disease and transplant outcomes
- World Intellectual Property Organization (WIPO) — International patent database
- The Transplantation Society — Clinical guidance on complement-mediated rejection
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform. This page represents a snapshot of innovation signals within the retrieved dataset only and should not be interpreted as a comprehensive view of the full field, clinical pipeline, or regulatory landscape.
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