Lysinuric Protein Intolerance Drug Pipeline — PatSnap Eureka
Lysinuric Protein Intolerance: Drug Pipeline & Therapy Approaches
LPI is a rare autosomal recessive disorder caused by SLC7A7 mutations with no approved pharmacotherapy. Explore dietary management, rGM-CSF, ASO, and emerging gene therapy signals — and discover a vacant IP landscape ripe for first-mover innovation.
Multi-system phenotype axes — PatSnap Eureka analysis
SLC7A7: The Sole Causative Gene in LPI
Lysinuric protein intolerance (LPI) is a rare autosomal recessive inborn error of metabolism caused by pathogenic variants in SLC7A7, encoding the cationic amino acid transporter subunit y+LAT1. The encoded protein functions as the light chain subunit of the heterodimeric system y+L amino acid transporter, responsible for basolateral transport of cationic amino acids — lysine, arginine, and ornithine — in intestinal epithelial cells, renal proximal tubular cells, and non-epithelial cells including macrophages and monocytes.
Deficient intestinal absorption and renal reabsorption of arginine and ornithine impair urea cycle function, producing episodic hyperammonemia after protein-rich meals. The retrospective cohort from Necker Hospital, Paris reported hyperammonemia in 10 of 16 patients across a 37-year follow-up period — the largest LPI cohort in the retrieved dataset.
The broader amino acid transporter disorder landscape, reviewed by Instituto de Investigación Biomédica de Málaga, identifies 11 SLC transporter families encompassing over 400 genes with known disease associations, providing a framework for understanding LPI within a larger class of transportopathies. Researchers and drug developers can leverage PatSnap's innovation intelligence platform to map this landscape systematically.
Multiple retrieved case reports document SLE-like autoimmune phenotypes — including Lupus nephritis, hemophagocytic lymphohistiocytosis (HLH), anti-nuclear antibodies, and cytopenias — underscoring a role for the y+LAT1 transporter in immune cell biology beyond simple amino acid transport.
LPI Drug Pipeline: From Dietary Management to Gene Therapy
Six therapeutic approaches identified across retrieved patent and literature records, ranging from established standard-of-care dietary strategies to emerging molecular modalities with no current LPI-specific filings.
Dietary Protein Restriction & Citrulline Supplementation
Protein-restricted diets are the primary intervention to reduce hyperammonemic episodes. Citrulline supplementation is the current standard to prevent hyperammonemia by bypassing the urea cycle defect, though the Barcelona Slc7a7 knockout mouse study notes its incomplete efficacy for systemic complications including PAP. No retrieved patent directly claims citrulline for LPI.
Standard of CareInhaled Recombinant GM-CSF for LPI-Associated PAP
The closest signal to a disease-modifying biological intervention in the retrieved dataset. A case series of two Chinese sisters with SLC7A7 mutations: one patient received inhaled rGM-CSF at 5 µg/kg twice daily for 18 months with reported clinical improvement and no adverse effects. This represents the only disease-modifying agent signal identified.
Compassionate UseLarge Neutral Amino Acid (LNAA) Strategies
Retrieved results document LNAA therapy for phenylketonuria (PKU), a related amino acid transport disorder where competitive transport blockade underlies the therapeutic rationale. Slow-release LNAA formulations increase plasma tyrosine levels in adult PKU patients (Padova, Italy). The pharmacological principle of LNAA competition at shared transporters such as LAT1/SLC7A5 is mechanistically proximate to y+LAT1 biology.
Clinical (PKU) / Preclinical (LPI)Antisense Oligonucleotide (ASO) Approaches
Two retrieved patents from CURna, Inc. describe antisense oligonucleotides targeting natural antisense transcripts of Alpha-L-Iduronidase (IDUA) to upregulate IDUA expression in Hurler syndrome. While not specific to LPI, these patents demonstrate the general applicability of antisense modulation to rare inherited metabolic transporter deficiencies, and the approach is mechanistically transferable to SLC7A7 upregulation strategies. A Radboud University study notes that 2'-O-methyl phosphorothioate ASOs can cause reversible proteinuria — a key safety consideration for renal transporter targets.
Preclinical / Patent-StageNonsense Suppression / Readthrough Strategies
Approximately 10% of disease-associated variants are in-frame premature termination codons (PTCs). Given that SLC7A7 harbors nonsense mutations in LPI patients — including a splice site mutation IVS4+1G>A in a Korean case and a nonsense mutation identified via whole exome sequencing at Baylor College of Medicine — PTC readthrough compounds represent a plausible modality. No LPI-specific readthrough patent or trial was retrieved.
EmergingMacrophage-Targeted Gene Correction
The macrophage-specific y+LAT1 defect in LPI-PAP, established by the Pavia study, combined with established precedent for macrophage-targeted gene therapy in other lysosomal storage diseases, signals hematopoietic stem cell gene therapy as a potentially relevant emerging modality. Macrophage-lineage SLC7A7 correction is identified as a distinct therapeutic goal from intestinal/renal correction. No retrieved result directly addresses this for LPI.
Conceptual / EmergingLPI Pipeline Intelligence: Key Data Visualised
Key quantitative signals from patent and literature analysis via PatSnap Eureka, illustrating the development stage distribution and institutional research footprint in the LPI space.
LPI Therapeutic Modalities by Development Stage
Pipeline distribution across six modalities — from standard-of-care dietary management to conceptual gene correction — based on retrieved patent and literature signals.
Innovation Activity Type in LPI Dataset
Innovation activity is predominantly literature-driven (academic research), with patent activity present but not specifically focused on LPI — illustrating the open IP opportunity.
Three Distinct Biological Axes Driving LPI Pathology
Mechanistic insights from retrieved patent and literature records identify separate therapeutic goals across intestinal, renal, and macrophage lineages — each requiring distinct correction strategies.
SLC7A7 / y+LAT1 Functional Characterisation
A mechanistic study from the University of Parma characterises LPI-causing mutations by expressing eGFP-tagged y+LAT1 mutant constructs in heterologous systems and measuring system y+L-mediated arginine uptake in monocytes and lymphoblasts from Italian LPI patients. Key findings: arginine transport is defective in patient monocytes; mutations cause variable mislocalization or destabilization of y+LAT1. The Finnish founder mutation (c.895-2A>T) is the most studied; Italian and other population mutations are heterogeneous with no genotype-phenotype correlation.
Macrophage y+LAT1 and PAP Pathogenesis
The Pavia study establishes that y+LAT1 transport activity is specifically absent in monocytes and differentiated macrophages from LPI-PAP patients, and identifies defective arginine transport in macrophages as potentially driving impaired surfactant clearance. This implicates macrophage-lineage SLC7A7 correction as a distinct therapeutic goal from intestinal/renal correction — pointing toward hematopoietic stem cell gene therapy approaches.
Six Emerging Combination Directions for LPI Therapy
Retrieved results signal several combination and emerging directions, though none are supported by formal trial data. All signals are derived from adjacent disease biology or mechanistic precedent.
| Combination Approach | Mechanism / Rationale | Evidence Source | Stage Signal |
|---|---|---|---|
| Dietary restriction + ammonia scavengers | Protein restriction reduces substrate; glycerol phenylbutyrate (GPB) or sodium benzoate detoxify residual ammonia | Argininosuccinate lyase deficiency case (GPB use); urea cycle disorder registry | Analogous clinical use |
| rGM-CSF + dietary management | Biologic superimposed on standard dietary management for PAP management | Chinese case report (Capital Institute of Pediatrics, 2017); 5 µg/kg twice daily × 18 months | Compassionate use |
| Dibasic AA supplementation + megalin pathway inhibition | High-dose lysine or arginine competitively inhibits megalin in proximal tubular cells, reducing pathological uptake | Bambino Gesù cystinosis study (2023); cross-disease pharmacological principle | Preclinical (cystinosis) |
| ASO upregulation of SLC7A7 | Target SLC7A7 natural antisense transcript to de-repress transporter expression; based on CURna IDUA ASO patent precedent | CURna, Inc. EP/HK patents (2018/2019); IP space open for LPI | Patent-stage precedent |
| Nonsense mutation readthrough | PTC readthrough compounds for ~10% of LPI variants that are in-frame PTCs | University of Alabama at Birmingham review (2016); Korean, Chinese, Turkish, Pakistani cohort mutation data | Emerging |
| Macrophage-targeted HSC gene correction | Hematopoietic stem cell gene therapy to correct macrophage-lineage y+LAT1 defect driving PAP | Pavia macrophage study (2010); LSd gene therapy precedent | Conceptual |
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Key Institutions Driving LPI Research
Innovation activity in this dataset is predominantly literature-driven. The following institutional footprints are identifiable across retrieved patent and academic records.
Necker Hospital / Imagine Institute / APHP, Paris
Largest reported LPI cohort in the dataset: 16 patients across a 37-year follow-up period. Primary clinical reference center for LPI in Europe. Published the definitive retrospective cohort analysis including hyperammonemia frequency, PAP incidence, and long-term outcomes.
16-patient cohort · 37-year follow-upHospital Sant Joan de Déu / University of Barcelona
Generated the tamoxifen-inducible Slc7a7 knockout mouse model — the only viable LPI animal model in the dataset (2019). Characterisation includes hyperammonemia, malabsorption, and PAP-like lung pathology, providing a platform for IND-enabling studies. Also describes citrulline supplementation as current standard of care.
Only viable Slc7a7 KO mouse modelUniversity of Parma & Fondazione IRCCS Pavia
Parma: functional characterisation of LPI-causing y+LAT1 mutations in monocytes and lymphoblasts, demonstrating variable mislocalization or destabilization. Pavia: established that y+LAT1 transport activity is specifically absent in monocytes and GM-CSF-differentiated macrophages from LPI-PAP patients — identifying macrophage surfactant clearance failure as a mechanistic driver.
y+LAT1 mutation functional mappingCURna, Inc. · MJN U.S. Holdings · N.V. Nutricia
CURna, Inc. holds EP and HK patents for ASO-mediated upregulation of IDUA (Hurler syndrome) — the mechanistic precedent most directly transferable to SLC7A7 ASO strategies. MJN U.S. Holdings holds an active EP patent for casein hydrolysate in inflammatory disease. N.V. Nutricia holds an active EP patent for non-digestible oligosaccharides for dietary protein tolerance induction. None have filed LPI-specific IP.
No LPI-specific IP filed by any assigneeAdditional key institutions: National Human Genome Research Institute (NIH) — clinical diagnostic guidance; Baylor College of Medicine — whole exome sequencing identification of SLC7A7 in atypical presentations; Bambino Gesù Children's Hospital (Rome) — cross-disease dibasic amino acid supplementation research; Capital Institute of Pediatrics (Beijing) — first reported Chinese LPI cases and rGM-CSF use for PAP. Life sciences researchers can explore the full institutional landscape via PatSnap's life sciences intelligence platform and customer case studies demonstrating rare disease R&D acceleration.
Four Strategic Signals for LPI Drug Developers
Key takeaways derived from the retrieved patent and literature dataset — each representing a concrete strategic consideration for rare disease programs targeting LPI.
IP Landscape for LPI Therapeutics is Essentially Vacant
No retrieved patent is specifically directed at SLC7A7, y+LAT1, or LPI. This represents a potential first-mover opportunity for gene therapy vectors, SLC7A7-targeted ASOs, or small molecule transporter modulators in a disease with no approved pharmacotherapy. The PatSnap open API enables systematic monitoring of this space.
Slc7a7 Knockout Mouse Model is a Critical Enabler
The 2019 Slc7a7 knockout mouse model from Barcelona recapitulates human phenotypes including PAP, hyperammonemia, and malabsorption. Its recent availability suggests the preclinical pipeline is nascent — drug developers seeking IND-enabling studies have access to a validated animal model that did not exist before 2019.
rGM-CSF for PAP is the Most Actionable Near-Term Signal
The retrieved compassionate-use case of inhaled rGM-CSF for LPI-associated PAP, combined with established regulatory precedent for rGM-CSF in autoimmune PAP, suggests a development pathway that could leverage existing clinical data and manufacturing infrastructure — potentially the shortest path to a disease-modifying intervention.
Diagnostic Underdetection is a Commercial Pipeline Barrier
Retrieved results from NIH, Pakistan, Turkey, Canada, and China document repeated delayed or missed diagnoses of LPI. IP strategies or orphan drug programs in this space will need to address the small and underdiagnosed patient population through companion diagnostics or newborn screening programs. The PatSnap Trust Center provides guidance on data governance for rare disease programs.
No Registered Trials — But Five Key Translational Signals
Retrieved results contain no evidence of registered clinical trials, IND filings, or regulatory submissions specifically for LPI pharmacotherapy or gene therapy. Clinical signals are limited to five identified areas across the dataset.
rGM-CSF inhalation for PAP was used compassionately in one patient (5-year-old Chinese girl with SLC7A7 mutations) at 5 µg/kg twice daily for 18 months with self-reported improvement — the only disease-modifying agent signal in the retrieved dataset. Citrulline supplementation is described as current standard of care for hyperammonemia prevention across multiple retrieved case reports, but no formal clinical trial data or efficacy endpoints are reported.
Prenatal dietary intervention is documented in one case: neonatal dietary adaptation following prenatal LPI diagnosis via ultrasonography prevented acute hyperammonemia in a Brussels case. Exome and next-generation sequencing diagnostics are increasingly used to diagnose LPI in atypical presentations — demonstrated by Baylor, University of Alberta, and NHGRI — and are a prerequisite for enrollment in any future clinical program.
The 2019 Slc7a7 knockout mouse model from Barcelona represents a critical preclinical translational resource that provides a platform for IND-enabling studies. Its characterisation — including hyperammonemia, malabsorption, and PAP-like lung pathology — means the preclinical pipeline is now enabled for the first time. For rare disease developers, PatSnap's life sciences solutions can accelerate target validation and competitive landscape mapping. Regulatory guidance from bodies such as EMA's Committee for Orphan Medicinal Products and FDA's Office of Orphan Products Development provides the framework for LPI orphan designation pathways.
Lysinuric Protein Intolerance Drug Pipeline — Key Questions Answered
LPI is caused by pathogenic variants in SLC7A7, encoding the cationic amino acid transporter subunit y+LAT1. The encoded protein functions as the light chain subunit of the heterodimeric system y+L amino acid transporter, responsible for basolateral transport of cationic amino acids (lysine, arginine, ornithine) in intestinal epithelial cells, renal proximal tubular cells, and non-epithelial cells including macrophages and monocytes.
Citrulline supplementation is described as the current standard to prevent hyperammonemia by bypassing the urea cycle defect, though the authors note its incomplete efficacy for systemic complications including PAP. Protein-restricted diets are the primary intervention to reduce hyperammonemic episodes.
LPI has an estimated prevalence of 1:50,000 in Finland and similar frequencies in Japan and Italy. Retrieved results from NIH, Pakistan, Turkey, Canada, and China document repeated delayed or missed diagnoses of LPI, indicating significant diagnostic underdetection globally.
Yes. The 2019 tamoxifen-inducible Slc7a7 knockout mouse model from Hospital Sant Joan de Déu, Barcelona represents a critical preclinical translational resource. Its characterization includes hyperammonemia, malabsorption, and PAP-like lung pathology, providing a platform for IND-enabling studies.
No patent assignee in this dataset has filed IP specifically directed at SLC7A7, LPI, or y+LAT1 correction. The patent landscape for LPI-specific therapeutics appears vacant in retrieved results, representing a potential first-mover opportunity for gene therapy vectors, SLC7A7-targeted ASOs, or small molecule transporter modulators.
The Pavia study establishes that y+LAT1 transport activity is specifically absent in monocytes and differentiated macrophages from LPI-PAP patients, and identifies defective arginine transport in macrophages as potentially driving impaired surfactant clearance. This implicates macrophage-lineage SLC7A7 correction as a distinct therapeutic goal from intestinal/renal correction.
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References
- Update on Lysinuric Protein Intolerance, a Multi-faceted Disease: Retrospective Cohort Analysis from Birth to Adulthood — Reference Center of Inherited Metabolic Diseases, Imagine Institute, Necker Hospital, APHP, Paris, France, 2017
- Lysinuric Protein Intolerance: Pearls to Detect This Otherwise Easily Missed Diagnosis — National Human Genome Research Institute, NIH, Bethesda, MD, 2019
- Lysinuric Protein Intolerance: An Overlooked Diagnosis — Gazi University Hospital, Ankara, Turkey, 2020
- Metabolic Disease with Autoimmune Phenomena: 2 Cases of SLE-like Disease in Young Children Diagnosed with Lysinuric Protein Intolerance — Charité – Universitätsmedizin Berlin, 2008
- Immune Dysregulation Mimicking Systemic Lupus Erythematosus in a Patient with Lysinuric Protein Intolerance: Case Report and Review of the Literature — Seattle Children's Hospital, 2021
- Inducible Slc7a7 Knockout Mouse Model Recapitulates Lysinuric Protein Intolerance Disease — Hospital Sant Joan de Déu, Barcelona, Spain, 2019
- Lysinuric Protein Intolerance in a Family of Mexican Ancestry with a Novel SLC7A7 Gene Deletion — Phoenix Children's Hospital, 2015
- Casein Hydrolysate for Use in Treating Inflammatory Diseases — MJN U.S. Holdings, LLC, 2020, EP [Patent]
- The First Korean Case of Lysinuric Protein Intolerance: Presented with Short Stature and Increased Somnolence — Seoul National University College of Medicine, 2012
- Lysinuric Protein Intolerance Mimicking N-Acetylglutamate Synthase Deficiency in a Nine-Year-Old Boy — University of Alberta, Stollery Children's Hospital, 2021
- Children with Lysinuric Protein Intolerance: Experience from a Lower Middle Income Country — Aga Khan University Hospital, Karachi, Pakistan, 2022
- Fanconi Syndrome with Lysinuric Protein Intolerance — University Federico II, Naples, Italy, 2014
- Lysinuric Protein Intolerance Presenting with Multiple Fractures — Baylor College of Medicine, Houston, TX, 2014
- In Lysinuric Protein Intolerance System y+L Activity is Defective in Monocytes and in GM-CSF-Differentiated Macrophages — Fondazione IRCCS Policlinico San Matteo, Pavia, Italy, 2010
- Mice Lacking the Intestinal and Renal Neutral Amino Acid Transporter SLC6A19 Demonstrate the Relationship between Dietary Protein Intake and Amino Acid Malabsorption — Australian National University, 2019
- Amino Acid Transport Defects in Human Inherited Metabolic Disorders — Instituto de Investigación Biomédica de Málaga-IBIMA, Spain, 2019
- Heterogeneous Colonic Content: A Prenatal Sonographic Manifestation of Lysinuric Protein Intolerance — Iris Hospitals South, Brussels, Belgium, 2020
- Dietary Supplementation of Cystinotic Mice by Lysine Inhibits the Megalin Pathway and Decreases Kidney Cystine Content — Bambino Gesù Children's Hospital, IRCCS, Rome, Italy, 2023
- New Mutations in the SLC7A7 Gene of Two Chinese Sisters with Lysinuric Protein Intolerance — Capital Institute of Pediatrics, Beijing, China, 2017
- Analysis of LPI-Causing Mutations on y+LAT1 Function and Localization — University of Parma, Italy, 2019
- Treatment of Alpha-L-Iduronidase (IDUA) Related Diseases by Inhibition of Natural Antisense Transcript to IDUA — CURna, Inc., 2018, EP [Patent]
- Treatment of Alpha-L-Iduronidase (IDUA) Related Diseases by Inhibition of Natural Antisense Transcript to IDUA — CURna, Inc., 2019, HK [Patent]
- Therapy with 2′-O-Me Phosphorothioate Antisense Oligonucleotides Causes Reversible Proteinuria by Inhibiting Renal Protein Reabsorption — Radboud University Medical Center, 2019
- Nonsense Suppression as an Approach to Treat Lysosomal Storage Diseases — University of Alabama at Birmingham, 2016
- Beneficial Effects of Slow-Release Large Neutral Amino Acids after a Phenylalanine Oral Load in Patients with Phenylketonuria — Federico II University, Naples, Italy, 2021
- Large Neutral Amino Acid Therapy Increases Tyrosine Levels in Adult Patients with Phenylketonuria: A Long-Term Study — University Hospital, Padova, Italy, 2019
- European Medicines Agency — Committee for Orphan Medicinal Products (COMP)
- U.S. Food and Drug Administration — Office of Orphan Products Development
- Orphanet — Rare Disease Database (LPI / SLC7A7)
All data and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform. This report is derived from a limited set of patent and literature records retrieved across targeted searches and represents a snapshot of innovation signals within this dataset only. It should not be interpreted as a comprehensive view of the full field, clinical pipeline, or regulatory landscape.
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