icerguastat (IFB-088) / InFlectis - LARVOL DELTA

Stress-Response Dysregulation Drives Bulbar-Specific Vulnerability In ALS Motor Neurons: Biological Rationale For A Precision Therapeutic Strategy (ENCALS 2026) - "Modulation of stress signalling by icerguastat selectively reduced TARDBP transcripts in bulbar-onset MNs, exceeding the effect observed with guanabenz. Icerguastat also markedly restored nuclear TDP-43 volume and enhanced acetylated and tyrosinated α-tubulin intensity, thereby normalizing cytoskeletal stability specifically in bulbar-onset MNs compared to spinal-onset ALS and control cells.Conclusion Together, these results uncover a cell intrinsic mechanism driving bulbar specific vulnerability in ALS and position icerguastat as a rational candidate for phenotype-tailored therapeutic strategies."

TARDBP

From Mechanisms To Therapy: A Multi-Target Combination Strategy In C9orf72-ALS (ENCALS 2026) - "The ASO was combined with a small molecule, icerguastat, modulating the unfolded protein response to mitigate DPR-induced proteotoxic stress.The therapy was tested in vitro in fibroblasts from ALS patients and age-matched controls, and the efficacy on foci, DPRs and autophagic function was assessed via RNAscope, immunofluorescence, and qPCR...In the in vivo model, ASO administration led to an increase in locomotor function and reduced the number of degenerated motor neurons compared to untreated animals.Conclusion Our results show that the multi-target therapy significantly reduced RNA foci and DPR accumulation, while restoring autophagic function in ALS fibroblasts. In vivo, GapmeR was well tolerated, rescued motor deficits, and reduced motor neuron loss with a dose-response relationship.These findings provide a proof-of-concept for a combinatorial therapy with translational potential towards clinical application in C9orf72-ALS patients."

Advanced Oxidation Protein Products exacerbate osteoarthritis progression by disrupting stress granules assembly via endoplasmic reticulum stress. (PubMed, Free Radic Biol Med) - "Further experiments demonstrated that the GADD34-specific inhibitor Sephin1 effectively restores eIF2α phosphorylation and rebuilds SGs formation, significantly alleviating OA progression...In vivo studies confirmed that its efficacy is comparable to intra-articular injection, while offering the advantages of being minimally invasive and safe. This research not only elucidates a novel mechanism of the AOPPs-ERS-SGs axis in OA pathogenesis but also provides a new therapeutic target and delivery strategy for OA treatment."

Journal • Immunology • Osteoarthritis • Pain • Rheumatology • ATF4 • PPP1R15A

Sephin1 alleviates white matter injury by protecting oligodendrocyte after intracerebral hemorrhage. (PubMed, J Cereb Blood Flow Metab) - "Additionally, Sephin1 attenuated neuroinflammation after ICH by inhibiting microglial polarization to the pro-inflammatory phenotype. Together, our observations suggest that Sephin1 is a promising therapeutic drug to alleviate WMI in ICH patients, highlighting its translational potential to improve neurological recovery in hemorrhagic stroke."

Journal • Cardiovascular • Cerebral Hemorrhage • Hematological Disorders • Inflammation • Solid Tumor • PPP1R15A

Directional Modulation of the Integrated Stress Response in Neurodegeneration: A Systematic Review of eIF2B Activators, PERK-Pathway Agents, and ISR Prolongers. (PubMed, Biomedicines) - "Typical regimens included ISRIB 0.1-2.5 mg per kg given intraperitoneally (often two to three doses) with reduced ATF4 and phosphorylated eIF2α; oral GSK2606414 50 mg per kg twice daily for six to seven weeks, achieving brain-level exposures; continuous MK-28 delivery at approximately 1 mg per kg; and oral IFB-088 or Sephin1 given over several weeks. Directional ISR control yields consistent, context-dependent improvements in behavior, structure, or survival, with biomarker evidence of target engagement. Mechanism matching (down-tuning versus prolonging the ISR) and exposure-driven safety management are central for translation."

Journal • Review • Alzheimer's Disease • Amyotrophic Lateral Sclerosis • CNS Disorders • Huntington's Disease • Movement Disorders • ATF4 • EIF2B4 • PPP1R15A

SPLiCR-seq: A CRISPR-Based Screening Platform for RNA splicing Identifies Novel Regulators of IRE1α-XBP1 Signaling Under ER Stress. (PubMed, Nat Commun) - "Pharmacological inhibition of GADD34 using Sephin1 effectively suppressed XBP1 splicing and alleviated CAR-T cell exhaustion in an ex vivo model, leading to enhanced tumor-killing capacity across multiple cancer models. This work not only establishes a powerful new tool for systematically studying RNA splicing regulation but also uncovers a promising therapeutic strategy for improving CAR-T cell immunotherapy through modulation of the IRE1α-XBP1 pathway."

Journal • Oncology • PPP1R15A • XBP1

Pharmacological Enhancement of Integrated Stress Response Confers Protection in Calcific Aortic Valve Disease. (PubMed, JACC Basic Transl Sci) - "Importantly, ISR activators Guanabenz and Sephin1 effectively attenuate AVIC osteoblastic-like differentiation and mitigate CAVD in rabbits and mice, respectively. These findings highlight that pharmacological enhancement of the ISR is a promising therapeutic strategy for CAVD."

Journal • Cardiovascular • ATF4 • NOX4

PPP1R15A as a therapeutic target to overcome chemoresistance in AML: An in vitro study (ASH 2025) - "Then guanabenz was selected for combination studies with idarubicin(IC₅₀: 10 nM, MOLM-13; 1 nM , KASUMI-1) or cytarabine (100 nM)...Only guanabenz instead of sephin-1 led to decreased levels of cytotoxicity... Our findings identify PPP1R15A as a stress-adaptive regulator of chemoresistance in AML. Its depletion—either genetically or pharmacologically—rewires the DDR, disrupts mitochondrial and proteostasis networks, and amplifies apoptotic signaling upon chemotherapy. Targeting PPP1R15A sensitizes AML cells to genotoxic stress and represents a promising combinatorial strategy to overcome drug resistance and improve therapeutic efficacy."

Preclinical • Acute Myelogenous Leukemia • Hematological Malignancies • Leukemia • Metabolic Disorders • CASP3 • CD24 • DDIT4 • EEF1A1 • PPP1R15A

A novel, rapid, and practical prognostic model for sepsis patients based on dysregulated immune cell lactylation. (PubMed, Front Immunol) - "Additionally, global lactylation levels were significantly elevated in THP-1 cells following treatment with Sephin1, a selective PPP1R15A inhibitor, suggesting a mechanistic link. Lactylation is significantly associated with increased mortality risk in sepsis. The proposed individualized prognostic model, based on dysregulated immune cell metabolism, accurately predicts early mortality and may inform optimized clinical management of septic patients."

Biomarker • Journal • Infectious Disease • Septic Shock • PIP5K1C • PPP1R15A

Sephin1 reduces TDP-43 cytoplasmic mislocalization and improves motor neuron survival in ALS models. (PubMed, Life Sci Alliance) - "Sephin1 improves motor neuron survival in ALS models by reducing TDP-43 cytoplasmic mislocalization and its toxicity. These findings open new therapeutic opportunities for Sephin1 in neurodegenerative pathologies with TDP-43 proteinopathy, including ALS."

Journal • CNS Disorders • Proteinopathy • TARDBP

The GADD34 Inhibitor Sephin1 Promotes Airway Repair and Prevents Chemical-induced Bronchiolitis Obliterans in Rats Through the Integrated Stress Response (ATS 2025) - "The GADD34 inhibitor Sephin1 promotes airway repair and prevents significant airway remodeling in rats exposed to occupational relevant doses of diacetyl vapors. Future studies remain underway validating the changes seen in airway basal cells isolated from exposed rats as well as targeting airways specifically using nebulized formulations of the GADD34 inhibitor. Sephin1 and other therapies targeting the integrated stress response may be promising therapeutic options for those suffering from chemical-induced BO - a devastating disease with no FDA approved medications."

Preclinical • Pulmonary Disease • Respiratory Diseases • ATF4 • EIF2A • EIF2S1 • PPP1R15A

Treatment Combining Riluzole and IFB-088 in Bulbar Amyotrophic Lateral Sclerosis (TRIALS Protocol) (clinicaltrials.gov) - P2 | N=51 | Completed | Sponsor: InFlectis BioScience | Active, not recruiting ➔ Completed

Trial completion • Amyotrophic Lateral Sclerosis • CNS Disorders

Sephin1 suppresses ER stress-induced cell death by inhibiting the formation of PP2A holoenzyme. (PubMed, Cell Death Dis) - "Phosphorylated AMPK is inactivated by PP2A through dephosphorylation of its Thr172, and Sephin1 inhibits the formation of the PP2A holoenzyme with the PP2A subunit B isoform delta. These results indicate that inhibition of PP2A holoenzyme formation is the molecular target of Sephin1 in this experimental system."

Journal • CNS Disorders • Targeted Protein Degradation • TNS1

Harnessing osmotic shock for enhanced intracellular delivery of (nano)cargos. (PubMed, Int J Pharm) - "When primary fibroblasts derived from amyotrophic lateral sclerosis (ALS)-patients were exposed to hypotonic shock in the presence of the therapeutic cargo icerguastat, there was an increased expression of miR-106b-5p compared to isotonic conditions. In conclusion, osmotic shock presents a promising strategy for improving drug delivery within cells and, potentially, in tissues such as muscles or skin, where localized drug administration is preferred."

Journal • Amyotrophic Lateral Sclerosis • CNS Disorders • MIR106B

PPP1R15A-expressing monocytic MDSCs promote immunosuppressive liver microenvironment in fibrosis-associated hepatocellular carcinoma. (PubMed, JHEP Rep) - "Notably, pharmacological inhibition of PPP1R15A by Sephin1 reduced the immunosuppressive potential but increased the maturation status of fibrotic HCC patient-derived M-MDSCs...The results from the preclinical models show that specific inhibition of PPP1R15A can break the immunosuppressive barrier to restrict hepatocellular carcinoma growth and enhance the efficacy of immune checkpoint blockade. PPP1R15A may also function as a prognostic and/or predictive biomarker in patients with hepatocellular carcinoma."

Journal • Fibrosis • Gastrointestinal Cancer • Hepatocellular Cancer • Hepatology • Immunology • Liver Cirrhosis • Oncology • Solid Tumor • CD8 • GZMB • IFNG • PPP1R15A • S100A8 • TGFB1 • TNS1

Sephin1 enhances integrated stress response and autophagy to alleviate myocardial ischemia-reperfusion injury in mice. (PubMed, Biomed Pharmacother) - "Sephin1 enhances ISR and related protein synthesis suppression, ameliorates myocardial apoptosis, and promotes autophagy during MIR stress. Sephin1 could act as a noval ISR enhancer for managing acute myocardial ischemia disease."

Journal • Preclinical • Cardiovascular • Myocardial Ischemia • Reperfusion Injury

Improved Neuromuscular Junction in R98C Mpz Heterozygous Mice Treated with IFB-088 (AAN 2024) - "These data, combined with prior behavioral and physiological studies demonstrate that IFB088 improves the neuropathy of R98C MPZ CMT1B mice, a model of CMT1B involving UPR activation."

Preclinical • Genetic Disorders • Pain • MPZ • PPP1R15A

Treatment Combining Riluzole and IFB-088 in Bulbar Amyotrophic Lateral Sclerosis (TRIALS Protocol) (clinicaltrials.gov) - P2 | N=51 | Active, not recruiting | Sponsor: InFlectis BioScience | Recruiting ➔ Active, not recruiting

Enrollment closed • Amyotrophic Lateral Sclerosis • CNS Disorders

PERK modulation, with GSK2606414, Sephin1 or salubrinal, failed to produce therapeutic benefits in the SOD1G93A mouse model of ALS. (PubMed, PLoS One) - "Amyotrophic lateral sclerosis (ALS) has been linked to overactivity of the protein kinase RNA-like ER kinase (PERK) branch of the unfolded protein response (UPR) pathway, both in ALS patients and mouse models. Clonidine also produced some favorable therapeutic effects, which were unexpected and not linked to the UPR. In conclusion, this study highlights the challenges of pharmacologically targeting PERK for therapeutic purposes in the SOD1G93A mouse model and suggests that exploring other targets within, and outside, the UPR may be more promising avenues for ALS treatment."

Journal • Preclinical • Amyotrophic Lateral Sclerosis • CNS Disorders

Phase 2 trial of oral IFB-088 for bulbar-onset ALS now fully enrolled (ALS News Today) - "Enrollment is complete in a Phase 2 trial testing InFlectis BioScience’s oral candidate IFB-088 (icerguastat) in people with amyotrophic lateral sclerosis (ALS), the company has announced. The trial (NCT05508074) enrolled a total of 50 adults with bulbar-onset ALS, a form of the disease that first affects the muscles in the head and neck, leading to swallowing, chewing, and speech difficulties."

Enrollment closed • Amyotrophic Lateral Sclerosis • CNS Disorders

Inhibition of PPP1R15A alleviates osteoporosis via suppressing RANKL-induced osteoclastogenesis. (PubMed, Acta Pharmacol Sin) - "Knockdown of PPP1R15A or application of Sephin1 (a PPP1R15A allosteric inhibitor in a phase II clinical trial) significantly inhibited osteoclastogenesis in vitro...PPP1R15A inhibition also suppressed pathogenic osteoclastogenesis in CD14 monocytes from osteoporosis patients. These results identify PPP1R15A as a novel regulator of osteoclastogenesis and a valuable therapeutic target for osteoporosis."

Journal • Osteoporosis • Rheumatology • CD14 • FOS • NFATC1 • PPP1R15A • TNS1

Integrated Stress Response in alpha synucleinopathy (Neuroscience 2023) - "While inhibition of Gadd34 is neuroprotective multiple models of neurodegeneration, inclusing motor neuron disease and multiple sclerosis, we show that neither the pharmacological inhibition of Gadd34, using Guanabenz and Sephin-1, or genetic loss Gadd34 function attenuated α-synucleinopathy in TgA53T model...Our data show that PERK-eIF2α pathway is an important pathological axis for α-synucleinopathy and different phosphatases are differentially involved in various neurodegenerative conditions. Moreover, we show that ISR components, particularly inhibition of CReP, is a therapeutic target for α-synucleinopathy."

Amyotrophic Lateral Sclerosis • CNS Disorders • Parkinson's Disease • PPP1R15A • PPP1R15B • TNS1

Sustained OMA1-mediated integrated stress response is beneficial for spastic ataxia type 5. (PubMed, Brain) - "In agreement, pharmacological potentiation of ISR via Sephin-1, a drug that selectively inhibits the stress-induced eIF2alpha phosphatase GADD34 (encoded by Ppp1r15a), improved cell growth of SPAX5 fibroblasts, and cell survival and dendritic arborization ex vivo in primary Afg3l2-/- Purkinje neurons (PNs)...These data indicate that activation of the OMA1-DELE1-HRI pathway is protective in the context of SPAX5. Pharmacological tuning of the ISR may represent a future therapeutic strategy for SPAX5 and other cerebellar ataxias caused by impaired mitochondrial proteostasis."

Journal • Ataxia • CNS Disorders • Dystonia • Epilepsy • Movement Disorders • Ocular Inflammation • ATF4 • CHAC1 • OPA1 • PLAA • PPP1R15A

Protocol for PPP1R15A-inhibited mouse model establishment with subcutaneous B16F1 tumor and single-cell analysis. (PubMed, STAR Protoc) - "Here, we present a protocol for exploring the effects of PPP1R15A inhibitor, Sephin1, on antitumor immunity of B16F1 subcutaneous tumor in mice...We then detail procedures for gene differentiation, regulon and cell-cell communication analysis, and validation of single-cell analysis results. For complete details on the use and execution of this protocol, please refer to Wang et al.."

Journal • Preclinical • Oncology • PPP1R15A

Therapeutic potential of endoplasmic reticulum stress inhibitors in the treatment of diabetic peripheral neuropathy. (PubMed, Metab Brain Dis) - "Factors like disrupted calcium signaling, dyslipidemia, hyperglycemia, inflammation, insulin signaling, and oxidative stress disturb the UPR sensor levels manifesting as DPN. We discuss new effective therapeutic alternatives for DPN that can be developed by targeting UPR pathways like synthetic ER stress inhibitors like 4-PhenylButyric acid (4-PBA), Sephin 1, Salubrinal and natural ER stress inhibitors like Tauroursodeoxycholic acid (TUDCA), Cordycepin, Proanthocyanidins, Crocin, Purple Rice extract and cyanidin and Caffeic Acid Phenethyl Ester (CAPE)."

Journal • Review • Alzheimer's Disease • CNS Disorders • Diabetes • Diabetic Neuropathy • Dyslipidemia • Gastroenterology • Gastrointestinal Disorder • Immunology • Metabolic Disorders • Movement Disorders • Oncology • Pain • Parkinson's Disease • Peripheral Neuropathic Pain