exaluren (ELX-02) / Eloxx Pharma - LARVOL DELTA

Small Molecule Premature Termination Codon Readthrough Therapy: A Phase 2 Pediatric and Adult Trial in Nonsense Mutation Alport Syndrome (KIDNEY WEEK 2024) - "ELX-02 is a small molecule that induces readthrough of premature (but not native) stop codons and is efficiently taken up by cells expressing megalin, allowing full length protein to be made by podocytes or tubular cells in the presence of a nonsense mutation... This first evidence of efficacy of a gene-targeted therapy in a podocyte-based Mendelian disease justifies a follow-on randomised-controlled study to quantify the potential for clinical benefit. Therapeutic readthrough of premature termination codons in Alport Syndrome suggests other genes expressed by megalin-expressing kidney cells may be targetable with this approach."

Clinical • Late-breaking abstract • P2 data • Genetic Disorders • Nephrology • Pediatrics • Renal Disease

Novel readthrough agent suppresses nonsense mutations and restores functional type VII collagen and laminin 332 in epidermolysis bullosa. (PubMed, Mol Ther Nucleic Acids) - "ELX-02, an aminoglycoside analog, has demonstrated superior PTC readthrough activity and lower toxicity compared to gentamicin in various genetic disorders. This is the first study demonstrating that ELX-02 can induce PTC readthrough and restore functional C7 and laminin 332 in RDEB and JEB caused by nonsense mutations. Therefore, ELX-02 may offer a novel and safe therapy for RDEB, JEB, and other inherited skin diseases caused by nonsense mutations."

Journal • Dermatology • Genetic Disorders • COL7A1 • LAMA3 • LAMC2

Determining the functional consequences of translational readthrough at common CFTR nonsense mutations (NACFC 2024) - "When we used other small-molecule compounds, such as SRI-41315 and ELX-02, to induce readthrough of G542X and G550X, we observed no major differences from the variants produced with G418-mediated readthrough. WT CFTR protein was produced upon readthrough of some CFTR PTC contexts used in this study (Y122X, Q493X, R553X, Y1092X). However, CFTR variant proteins were also created. Overall, readthrough at seven CF-causing PTCs yielded 12 variant CFTR protein possibilities."

Cystic Fibrosis • Genetic Disorders • Immunology • Respiratory Diseases

Rescue of CFTR nonsense mutations is enhanced under inflammatory stimuli (NACFC 2024) - "Cells were also treated in the last 24 hours with ELX-02 (200 µM) plus VX-809 (1 µM) with or without CC-90009 (0.1 µM). We found that cytokine-treated epithelia had an enhanced response to the triple compound combination containing the eRF3a degrader CC-90009. We are investigating the molecular basis of this behavior because the cytokine treatment may change expression of genes controlling protein synthesis, thus potentiating the effect of readthrough maneuvers."

Cystic Fibrosis • Genetic Disorders • Immunology • Respiratory Diseases • GSPT1 • IL17A • IL4 • TNFA

Development of a drug testing platform for CFTR premature termination codon variants based on rectal organoids (NACFC 2024) - "Incubation with the aminoglycoside G418, as expected from the literature, caused a significantly greater in FIS rate than control (vehicle) and ELX-02 or PTC124, with further improvement in combination with CFTR modulators (elexacaftor/tezacaftor/ivacaftor [ETI]). Our preliminary data indicate that the levels of swelling induced by G418+ETI reached reference AUC values of F508del/F508del organoids treated with VX809/ VX770 (mean 2,487.9 ± 504). Our data show that this platform may be able to evaluate the drug response that reflects variability in genotypes and individual response to pharmacological treatment to direct clinical research toward a rapid, reliable evaluation of the most promising compounds for CFTR PTC variants. Additional candidate readthrough molecules are being studied using this screening and validation platform."

Cystic Fibrosis • Genetic Disorders • Immunology • Respiratory Diseases

Targeting elexacaftor/tezacaftor/ivacaftor-unresponsive CFTR mutations: novel drug combos in patient-derived organoids (NACFC 2024) - "We tested combinations of phosphodiesterase-4 (PDE4) inhibitors (roflumilast, apremilast) and the readthrough agent ELX-02 with a nonsense-mediated mRNA decay (NMD) inhibitor (SMG1i), alongside ETI. Testing combinations of modulators for mutations insufficiently responsive to or ineligible for ETI in PDROs can open novel therapeutic solutions for PwCF."

Clinical • Cystic Fibrosis • Genetic Disorders • Immunology • Respiratory Diseases • CFTR

Screening for translational readthrough of CFTR R1162X leads to the identification of mammalian target of rapamycin inhibitors for nonsense suppression (NACFC 2024) - " Combining aminoglycosides (G418, ELX-02) with CC-90009 results in translational readthrough of native CFTR R1162X, achieving full-length CFTR protein levels equivalent to 20% of normal CFTR expression in parental 16HBE14o- cells. Screening a repurposing library is an attractive option to accelerate drug discovery for PwCF with CFTR nonsense variants. Further evaluation of the effect of mTOR inhibitors on the readthrough of CFTR nonsense variants may help reveal their therapeutic potential in nonsense suppression."

CFTR • GSPT1

A novel induced pluripotent stem cell-derived intestinal organoid protocol to assess CF therapies (NACFC 2024) - "Results by FIS indicate matched functional responses to ELX-02 in multiple PTC variants... This work represents the next generation of intestinal differentiation from iPSCs and focuses on advancing therapies for rare and nonsense CFTR variants. We generated and validated an isogenic panel of iPSC intestinal organoids with PTC-CFTR mutations and have begun exploring potential curative strategies including SuperExon approaches."

Clinical • Cystic Fibrosis • Genetic Disorders • Immunology • Respiratory Diseases • CFTR • KRT20 • OLFM4

CFTR premature termination codon readthrough can be enhanced by a transcript-specific antisense oligonucleotide approach (NACFC 2024) - "We also investigated whether combining ASOs with PTC modulators such as aminoglycosides (G418, ELX-02) and eRF degraders (SRI-41315, CC-90009) enhances PTC readthrough. This study presents a new approach for enhancing specific PTC readthrough in CFTR using ASOs that target a sequence near PTCs. This approach has the potential to safely increase the efficacy of current PTC modulators without exacerbating transcriptome-wide undesired effects."

CFTR

Induced pluripotent stem cell-derived airway basal cell direct thaw protocol: A method to generate reproducible induced pluripotent stem cell-derived air-liquid-interface cultures (NACFC 2024) - "For example, representative AUC/min (mA/cm2) for a W1282X+/+ iBC line treated with ELX-02/CC-9009/VX445/VX661/VX770: Standard protocol = 2.67; iBC-direct thaw: 3.16. We have thoroughly analyzed the iBC-direct thaw protocol and shown its utility in CF research, specifically for genotypes with limited or no availability of primary cells. iBCs will be made available to the community upon request."

Cystic Fibrosis • Genetic Disorders • Immunology • Respiratory Diseases

Eloxx Pharmaceuticals Provides ELX-02 and ZKN-013 Program Updates (GlobeNewswire) - "Eloxx Pharmaceuticals, Inc...provided program updates for ELX-02 and ZKN-013, including Orphan Drug Designation (ODD) for ELX-02....Initiated Phase 1 Single Ascending Dose (SAD) study: Initiated Phase 1 SAD study in Australia with initial results expected in 2nd half of 2024."

Orphan drug • P1 data • Dermatology • Genetic Disorders • Muscular Dystrophy • Rare Diseases

Utilizing ribosome-directed small molecules and nucleotide-based approaches to overcome distinct subclasses of CFTR variants (NACFC 2023) - "Preliminary data indicate that investigational inhibitors of ribosome function, such as G418, ELX-02, and PTC-124, do not impair uL11 production in FRT cells...Escin has been subsequently employed to inform structure-guided high-throughput screens to establish lead compounds at which approximately 50% suppression of uL11 is attained... Partial depletion of uL11 is a feasible strategy for CFTR modulation that may be applicable to CFTR genotypes that are refractory to available clinical interventions. Overall, this work serves as a foundation from which future studies may be pursued to examine efficacy and tolerability of anti-uL11 compounds or ASOs delivered to CF animal models."

Pediatrics • CFTR

In vitro and ex vivo rescue of a nonsense mutation responsible for severe coagulation factor V deficiency. (PubMed, J Thromb Haemost) - "These findings provide in vitro and ex vivo proof-of-principle for readthrough-mediated rescue of the F5 p.Arg1161Ter mutation."

Journal • Preclinical • Hematological Disorders • ARG1 • F5

Novel eRF3 degrader monotherapy induces translational readthrough of CFTR nonsense mutations at therapeutically relevant levels (NACFC 2023) - "CC-90009 rescued W1282X-CFTR func-tion to approximately 20% of wt levels and, when paired with G418, rescued G542X-CFTR function to approximately 50% of wt levels in Bmi-1/hTERT airway epithelial cell lines [1]...SRI-47749 combined with ELX-02 (53 μg/mL) and CFTR modulators (elexacaftor-tezacaftor-ivacaftor, 3 uM) increased forskolin-induced swelling in organoids from the same donors, reaching approximately 5% to 25% of the wt control. SRI-47749 is a novel compound that induces translational readthrough by degrading eRF3, which restores substantial CFTR function from PTC alleles in primary organoids. Further research for development of SRI-47749 as a monotherapeutic agent for people with CF with PTCs is ongoing."

Monotherapy • Targeted Protein Degradation • BMI1 • CFTR • CRBN • GSPT1

Identifying the amino acid(s) inserted upon premature termination codon readthrough and their effect on CFTR functionality (NACFC 2023) - "When we used other small-molecule compounds such as SRI-41315 and ELX-02 to induce RT of G542X and G550X, we observed no major differences from the variants produced with G418-mediated RT. Our results indicate that the local PTC mRNA context greatly affects the identity and frequency of amino acid incorporation upon RT. We are examining the functionality of the CFTR variants created upon RT and whether they are susceptible to HEMT. Additionally, as we observed similar amino acid incorporation profiles for two different classes of RT compounds at two different CFTR PTCs, we conclude that it is not the RT agent but rather the local sequence context that serves as the major determinant of amino acid incorporation upon RT."

Development of a robust protocol for functional assessment of CFTR in human primary enteric monolayer cultures grown on permeable filter supports (NACFC 2023) - "After treatment, CFTR nonsense readthrough was assessed by measuring the area under the curve of CFTR-mediated Cl– current between acute additions of CFTR agonists (10 mM forskolin + 1 mM ivacaftor) and a Table 1...hPEM cultures cultured in 1:1 medium for 13 days followed by 2 days in differentiation medium (13+2) developed TEER values between 500 and 1,000 ohms/cm2 , and combin-ation treatments of ELX-02 or G418, with 10 nM CC-90009 generated Emax of 28.5 ± 1.4 mA/cm2 and 41.6 ± 1.3 mA/cm2 , respectively, and EC50 of 65.7 ± 8.2 mM and 64.9 ± 2.9 mM, respectively. We have established a robust protocol for preparation of an IO-derived, electrophysiologically competent primary cell model to aid in discovery and profiling of novel therapeutics, particularly those targeting nonsense and other rare CFTR mutations."

CFTR • GSPT1 • WRN

Comparing functional responses of nonsense CFTR variants to modulators in human primary enteric monolayer, human bronchial epithelial, and 16hBEge cell cultures (NACFC 2023) - "hPEM cultures were maintained in 1:1 organoid growth medium (IntestiCult) and L-WRN conditioned media for 13 days and then switched to Translational Tissue Modeling Laboratory differentiation media supplemented with vehicle or increasing concentrations of aminoglycosides (G418, ELX-02) ± CC-90009 for 2 days. After treatment, CFTR nonsense readthrough was assessed by measuring the area under the curve of CFTR-mediated Cl– current between acute additions of CFTR agonists (10 mM forskolin + 1 mM ivacaftor) and a CFTR-specific inhibitor cocktail (20 mM CFTR-inh172/20 mM GlyH-101) on a 24-channel current clamp system (TECC-24, EP Design, Belgium)... The qualitative correlation in nonsense readthrough modu-lator responses between the tested cell models validates their utility as part of an in vitro screening paradigm for discovery of novel readthrough active compounds."

Preclinical • GSPT1 • WRN

Screening the Calibr ReFRAME drug-repurposing library for efficient functional restoration of native CFTR nonsense variants (NACFC 2023) - "Background: Drugs in clinical trials for readthrough of CF-causing nonsense mutations have failed (ataluren) or not yet demonstrated meaningful efficacy (ELX-02)... Combinations of AGS (G418 or ELX-02) and CC-90009 for the translational readthrough of native CFTR R1162X achieved full-length CFTR protein levels of 20% of normal expression in parental 16hBE14o– cells, analyzed by CFTR ELISA and Western blotting... Screening a repurposing library is an attractive option to speed drug discovery for PwCF with CFTR nonsense variants. Our next step will focus on combinational profiling of hits to explore synergies for the readthrough of CFTR PTC variants and down-selection of hits for hit-to-lead optimization."

GSPT1

Eloxx Pharmaceuticals Provides Program Updates on ELX-02 and ZKN-013 (GlobeNewswire) - P1 | N=8 | NCT05448755 | Sponsor: Eloxx Pharmaceuticals, Inc. | "Eloxx Pharmaceuticals...today provided an update on the continued advancement of ELX-02 for the treatment of Alport syndrome with nonsense mutations, including additional positive results from its Phase 2 clinical study evaluating ELX-02...Based on the encouraging clinical results to date, Eloxx has submitted an IND application with the U.S. FDA for ELX-02 for the treatment of Alport syndrome with nonsense mutations. Allowance of the IND will allow for the inclusion of U.S.-based sites in the planned pivotal trial....Biopsy Results from ELX-02 Phase 2 Alport Trial Support Protein Restoration: All three patients (100% response rate) treated with ELX-02 in its proof-of-concept Phase 2 open-label clinical trial (NCT05448755) showed an improvement in podocyte foot process effacement, a hallmark of proteinuric kidney diseases like Alport syndrome."

IND • New trial • P2 data • Genetic Disorders

A Phase 2 Study to Evaluate the Safety, Tolerability, PK and PD in Cystic Fibrosis Patients With at Least 1 G542X Allele (clinicaltrials.gov) - P2 | N=17 | Completed | Sponsor: Eloxx Pharmaceuticals, Inc. | Recruiting ➔ Completed

Trial completion • Cystic Fibrosis • Fibrosis • Genetic Disorders • Immunology • Pulmonary Disease • Respiratory Diseases

In vitro and ex vivo rescue of a nonsense mutation (F5 p.Arg1161Ter) responsible for severe coagulation factor V deficiency (ISTH 2023) - "COS-1 cells transfected with the FV p.Arg1161Ter cDNA secreted hardly any functional FV (FV activity: 0.8±0.3% of wild-type). Treatment with G418, ELX-02 and 2,6-diaminopurine increased FV activity in a dose-dependent manner (up to 4.7-fold, 2.8-fold and 13.6-fold, respectively), while PTC-124 and amlexanox were ineffective. All readthrough agents except ELX-02 showed some degree of cytotoxicity."

Preclinical • Hematological Disorders • ARG1

Eloxx Pharmaceuticals Announces Final Data Assessment from Phase 2 Combination Clinical Trial of ELX-02 in Class 1 Cystic Fibrosis (CF) Patients (GlobeNewswire) - P2 | N=16 | NCT04135495 | Sponsor: Eloxx Pharmaceuticals | "Eloxx Pharmaceuticals...announced the final data assessment from the Phase 2 clinical trial of ELX-02 in combination with ivacaftor in Class 1 CF patients with at least one nonsense mutation. In the final assessment, ELX-02 demonstrated clinically relevant improvement in ppFEV1....6 of 13 patients entered trial from monotherapy arm (after average 463 days) and had a decrease in lung function (annualized -4.26% reduction in ppFEV1) due to disease progression. Treatment with ELX-02 stabilized disease overall and resulted in a clinically relevant increase in ppFEV1 in six of thirteen patients based on change in ppFEV1 at the end of treatment at Day 35 compared to the start of treatment at Day 1....ELX-02 was generally well tolerated in the trial, with no treatment-related serious adverse events noted."

P2 data • Cystic Fibrosis • Genetic Disorders

Eloxx Pharmaceuticals Reports First Quarter 2023 Financial and Operating Results and Provides Business Update (GlobeNewswire) - "R&D expenses were $3.5 million for the three months ended March 31, 2023, which included $0.3 million in stock-based compensation. For the same period in the prior year, R&D expenses were $7.9 million, which included $0.4 million of stock-based compensation. The decrease was primarily related to a decrease in clinical trial expenses for activities related to inhaled delivery of ELX-02 in cystic fibrosis and a decrease in clinical trial expenses related to a decrease in Cystic Fibrosis Foundation funded activities."

Commercial • Cystic Fibrosis

Exaluren: Expiry of patents related to compounds, pharmaceutical compositions, methods of use and compositions to treat genetic disorders, in US, EU, Canada, Hong Kong, India, Israel, and Japan in 2031 (Eloxx Pharma) - Annual Report 2022: Expiry of patents related to methods for large-scale synthesis and compound in US, EU, Australia, Israel, India, Japan, Brazil, Canada, China and Hong Kong in 2038; Expiry of patents related to methods and compounds to treat various ocular conditions in US. EU Australia, Canada, China, Hong Kong, Israel, Japan, Mexico, Malaysia, New Zealand, Philippines, Singapore, South Africa, and South Korea in 2039

Patent • Cystic Fibrosis

ELX-02 suppress premature stop mutations and restores type VII collagen and laminin 332 function in RDEB and JEB (ISID 2023) - "We showed previously that topical or intravenous gentamicin induced PTC readthrough, leading to C7 and laminin 332 production in RDEB and JEB patients. Using an in vitro three-dimensional skin equivalent model, we showed that ELX-02 induced C7 in RDEB cells and laminin 332 in JEB cells, correctly localizing at the dermal-epidermal junction. Therefore, ELX-02 may offer a novel and safe therapy for RDEB and JEB and other inherited skin diseases caused by PTC mutations."

Dermatology • Genetic Disorders • LAMA3 • LAMC2