Category: Uncategorized

  • Acoramidis

    Selective transthyretin tetramer kinetic stabilizer designed to mimic the naturally occurring T119M protective variant

    A fluorinated benzoic acid derivative engineered to replicate the enthalpy-driven transthyretin stabilization of the protective T119M genetic variant, approved for transthyretin amyloid cardiomyopathy following a positive Phase 3 trial demonstrating reductions in all-cause mortality and cardiovascular hospitalization.

    Abstract

    Acoramidis (AG10) is a potent, selective, orally bioavailable small-molecule kinetic stabilizer of the transthyretin (TTR) tetramer, approved in the United States, European Union, United Kingdom, and Japan for the treatment of cardiomyopathy caused by wild-type or hereditary transthyretin-mediated amyloidosis (ATTR-CM). The compound was rationally designed to replicate the molecular mechanism of the naturally occurring T119M variant of TTR, a protective mutation that stabilizes the tetramer against the rate-limiting dissociation step that initiates amyloid fibril formation. Structurally, acoramidis is a 3,5-dimethylpyrazole linked through a propyloxy tether to a 4-fluorobenzoic acid; the pyrazole ring forms two hydrogen bonds with serine 117 and serine 117 prime residues at the floor of the thyroxine binding pocket, replicating the inter-dimer contact created by the threonine-to-methionine substitution in T119M carriers. This enthalpy-driven binding mechanism (binding enthalpy of negative 13.6 kilocalories per mole, compared to negative 5.0 kilocalories per mole for tafamidis) underpins the high selectivity of acoramidis for TTR over albumin and its capacity to achieve greater than 90 percent tetramer stabilization across the entire dosing interval at steady state. The clinical development program for acoramidis established pharmacokinetic parameters favorable for twice-daily oral dosing: rapid absorption (time to peak concentration less than one hour), terminal elimination half-life of approximately 25 hours, metabolism principally by UGT-mediated glucuronidation rather than cytochrome P450 enzymes, and renal elimination of conjugated metabolites. The pivotal Phase 3 ATTRibute-CM trial randomized 632 patients with wild-type or hereditary ATTR-CM to acoramidis 800 milligrams (as the hydrochloride salt) twice daily or placebo for 30 months. On the primary hierarchical endpoint (a four-component analysis of all-cause mortality, cardiovascular-related hospitalization, NT-proBNP change, and six-minute walk distance), acoramidis demonstrated a win ratio of 1.8 (95 percent confidence interval 1.4 to 2.2; P less than 0.001). The time-to-event composite of all-cause mortality or first cardiovascular hospitalization favored acoramidis with a hazard ratio of 0.64 (95 percent confidence interval 0.50 to 0.83; P equals 0.0008), with Kaplan-Meier curves separating at three months and benefit sustained through 42 months of follow-up in the open-label extension. A cardiac magnetic resonance substudy demonstrated stabilization of left ventricular mass and improvement of ejection fraction in the acoramidis arm relative to progressive deterioration in placebo recipients. The adverse event profile was similar to placebo; diarrhea (11.6 versus 7.6 percent) and gout (10.9 versus 8.1 percent) were the most frequent treatment-emergent events occurring at higher rates with acoramidis. This monograph reviews the chemistry, synthesis, and rational design of acoramidis; the enthalpy-driven TTR stabilization mechanism characterized through isothermal titration calorimetry and X-ray crystallography; the complete human pharmacokinetic profile; preclinical pharmacology in rodent and canine models; the clinical evidence base from Phase 1 through Phase 3 and the open-label extension; sourcing and quality considerations for research applications; reconstitution and handling; metabolic and pharmacodynamic interactions; the adverse event and safety profile; and a comparative assessment of five transthyretin-directed therapies (tafamidis, diflunisal, patisiran, vutrisiran, and eplontersen) against acoramidis on five competency standards. Acoramidis is a prescription medicine in its approved jurisdictions and is available as a research-grade preparation for investigational applications outside the approved indication. Investigators should obtain analytical confirmation of identity and purity on every research-grade lot.

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  • Simufilam

    Small-molecule filamin A conformation modulator proposed to disrupt amyloid beta-driven tau hyperphosphorylation and neuroinflammation in Alzheimer’s disease

    A spirocyclic triazaspirodecanone developed by Cassava Sciences to target an altered conformation of the scaffolding protein filamin A in Alzheimer’s disease, discontinued in November 2024 after two large Phase 3 randomized controlled trials failed to demonstrate cognitive or functional benefit over placebo.

    Abstract

    Simufilam (PTI-125) is an oral small-molecule drug candidate of the triazaspirodecanone structural class, developed by Cassava Sciences, Inc. for the treatment of mild-to-moderate Alzheimer’s disease (AD). The compound’s proposed mechanism centers on binding an altered conformation of the intracellular scaffolding protein filamin A (FLNA) that is reportedly induced by amyloid beta 1-42 (Abeta42) in AD brain tissue. According to the published preclinical literature, simufilam binds altered FLNA with femtomolar affinity and restores its native conformation, thereby disrupting two pathogenic signaling cascades: Abeta42 signaling via the alpha-7 nicotinic acetylcholine receptor (alpha7nAChR) that hyperphosphorylates tau protein, and persistent activation of toll-like receptor 4 (TLR4) that drives neuroinflammation. The proposed mechanism, if validated, would represent a first-in-class approach targeting a protein conformational change rather than a conventional receptor or enzyme.

    The preclinical and early clinical pharmacology of simufilam was developed almost entirely within the laboratory of Hoau-Yan Wang at the City University of New York (CUNY), in collaboration with Lindsay Burns, then chief science officer of Cassava Sciences. Published reports from this laboratory described femtomolar binding affinity for altered FLNA, picomolar efficacy in postmortem human brain tissue, and reduction of tau hyperphosphorylation, amyloid aggregation, and inflammatory cytokine release in intracerebroventricular Abeta42-infusion and triple-transgenic mouse models. A Phase 2a open-label study in 13 AD patients (100 mg twice daily for 28 days) reported significant reductions in cerebrospinal fluid biomarkers of neurodegeneration and neuroinflammation. These results, published in the Journal of Prevention of Alzheimer’s Disease in 2020, provided the basis for Phase 3 advancement. However, the Wang laboratory subsequently became the subject of data integrity investigations: a CUNY panel initially cited Wang for “egregious misconduct” across 20 papers (later reversed under a different evidentiary standard), a federal grand jury indicted Wang for fraud involving approximately 16 million dollars in NIH grants (charges later dropped), seven Wang papers have been retracted, and the Journal of Neuroscience issued expressions of concern for two foundational simufilam papers. In September 2024, the U.S. Securities and Exchange Commission charged Cassava Sciences with securities fraud, resulting in a 40 million dollar settlement and the resignation and barring of the chief executive officer and chief science officer. Independent replication of the proposed FLNA conformation-modulation mechanism has not been published by laboratories outside the Wang group.

    Two large Phase 3 randomized, double-blind, placebo-controlled trials evaluated simufilam in mild-to-moderate AD. The ReThink-ALZ trial (n = 804, simufilam 100 mg twice daily versus placebo for 52 weeks) found no significant difference on either co-primary endpoint: ADAS-Cog12 (least-squares mean difference negative 0.39, p = 0.431) or ADCS-ADL (difference 0.51, p = 0.403). The ReFocus-ALZ trial (n = 1,125, simufilam 50 mg or 100 mg twice daily versus placebo for 76 weeks) similarly failed all co-primary, secondary, and exploratory biomarker endpoints. No significant changes in plasma p-tau217, neurofilament light chain, or glial fibrillary acidic protein were observed. Simufilam was well tolerated in both trials, with an adverse event profile similar to placebo. Cassava Sciences discontinued the AD program in November 2024. An independent cell-culture assessment published in 2026 found that simufilam produced no beneficial effects on amyloid processing, neurotrophic factors, or mitochondrial function in differentiated human neuronal cells, aligning with the clinical outcomes.

    This monograph documents the chemistry, proposed molecular pharmacology, pharmacokinetics, preclinical pharmacology, the complete clinical evidence base including Phase 3 trial results, the data integrity controversies that accompanied development, sourcing and handling considerations, adverse event profile, and a comparative assessment of five Alzheimer’s disease therapeutic candidates against simufilam. The compound is not approved by any regulatory authority for any indication. Investigators considering simufilam for research applications should weigh the absence of independent mechanism validation, the complete Phase 3 clinical failure, and the unresolved questions regarding the integrity of the foundational preclinical data.

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  • ANAVEX 3-71

    Dual allosteric M1 muscarinic acetylcholine receptor agonist and sigma-1 receptor agonist

    A spirocyclic thiadiazine-piperidine compound developed at the Israel Institute for Biological Research as a dual allosteric M1 muscarinic and sigma-1 receptor agonist, distinguished by sub-nanomolar allosteric potency at M1, disease-modifying preclinical efficacy in transgenic Alzheimer’s disease models, and active clinical development across schizophrenia, frontotemporal dementia, and Alzheimer’s disease indications.

    Abstract

    ANAVEX 3-71 (development code AF710B; CAS 1235733-73-9) is a synthetic spirocyclic thiadiazine-piperidine compound and a dual allosteric agonist at the M1 subtype of the muscarinic acetylcholine receptor and the sigma-1 receptor (SIGMAR1). The compound was invented by Abraham Fisher at the Israel Institute for Biological Research (IIBR) in Ness Ziona, Israel, as the fourth generation of a series of cholinergic agonists (AF102B, AF267B, AF292, AF710B) with progressively greater selectivity and allosteric character at the M1 muscarinic receptor. ANAVEX 3-71 emerged from high-throughput receptogram profiling as a compound with sub-nanomolar allosteric binding affinity at M1 muscarinic receptors (approximately 0.05 nM) and nanomolar affinity at the sigma-1 receptor (Ki approximately 1.3 nM), with no agonistic activity at M2 through M5 muscarinic subtypes, no significant binding at alpha-4-beta-2 or alpha-7 nicotinic receptors, and a clean off-target profile across 83 additional G-protein-coupled receptors, ion channels, and transporters screened at 10 micromolar. The preclinical pharmacology of ANAVEX 3-71 has been characterized principally in three studies using transgenic rodent models of Alzheimer’s disease. Fisher et al. (2016) reported that AF710B at 10 micrograms per kilogram per day intraperitoneally for two months in 3xTg-AD mice reversed cognitive deficits in the Morris water maze, decreased BACE1, GSK3-beta activity, and tau phosphorylation at multiple epitopes (AT180, AT270, PHF-1), reduced soluble and insoluble amyloid-beta 40 and 42, and rescued mushroom dendritic spine loss in hippocampal neuronal cultures at 30 nanomolar. Hall et al. (2018) extended these findings to McGill-R-Thy1-APP transgenic rats, demonstrating that oral treatment at 10 micrograms per kilogram per day for 4.5 months at 13 months of age (postplaque) reverted cognitive deficits, reduced amyloid pathology and neuroinflammation, and increased cerebrospinal fluid amyloid clearance, with effects maintained following a 5-week treatment interruption consistent with disease-modifying rather than symptomatic activity. Orciani et al. (2023) demonstrated that early (preplaque, 7 months of age) treatment at the same dose for 7 months prevented cognitive impairment, reduced hippocampal plaque burden and cortical amyloid-beta peptides, attenuated microglial and astrocytic neuroinflammation, and rescued pro-BDNF to mature BDNF conversion, with effects persisting through a 4-week washout. Human pharmacokinetics characterized in a Phase 1 single ascending dose study (NCT04442945; 36 healthy volunteers; 5 to 200 mg) demonstrate linear, dose-proportional, and time-invariant pharmacokinetics with a mean apparent terminal elimination half-life of 3.56 hours for the parent compound and 6.59 hours for the M8 metabolite. No clinically relevant effects on QTc or other electrocardiographic parameters were observed across the full studied dose range. Food had no effect on the pharmacokinetics of ANAVEX 3-71 or its M8 metabolite. Clinical development is ongoing across multiple indications. A Phase 2 study in schizophrenia (NCT06245213; 71 subjects) reported dose-dependent improvements in electroencephalographic biomarkers and favorable safety and tolerability with no serious treatment-emergent adverse events. A modified-release oral tablet enabling once-daily dosing was successfully developed in a Phase 1b study completed in October 2025. ANAVEX 3-71 is not approved by any regulatory authority and is supplied as a research-grade preparation. This monograph reviews the chemistry, dual-receptor pharmacology, preclinical pharmacology in transgenic Alzheimer’s models, human pharmacokinetics, the clinical evidence base, sourcing and quality verification, handling considerations, interaction profile, adverse event signal, and a comparative assessment of five mechanistically related compounds against ANAVEX 3-71 on five competency standards.

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  • Tofersen

    Antisense oligonucleotide targeting SOD1 mRNA via RNase H-dependent degradation for SOD1-associated amyotrophic lateral sclerosis

    A 2′-O-methoxyethyl gapmer antisense oligonucleotide developed by Ionis Pharmaceuticals and Biogen for intrathecal reduction of SOD1 protein in genetically defined SOD1-associated amyotrophic lateral sclerosis, the first gene-targeted therapy approved for any form of ALS.

    Abstract

    Tofersen (BIIB067, marketed as Qalsody) is a 20-base 2′-O-methoxyethyl (MOE) gapmer antisense oligonucleotide that binds to and mediates RNase H-dependent degradation of superoxide dismutase 1 (SOD1) messenger RNA, reducing synthesis of both mutant and wild-type SOD1 protein in the central nervous system. Developed by Ionis Pharmaceuticals and licensed to Biogen, tofersen received accelerated approval from the United States Food and Drug Administration on April 25, 2023, for the treatment of amyotrophic lateral sclerosis (ALS) in adults with a confirmed SOD1 gene mutation, making it the first gene-targeted therapy approved for any form of ALS. Subsequent approvals followed from the European Medicines Agency (May 30, 2024), the Therapeutic Goods Administration of Australia (January 5, 2025), and Health Canada (March 3, 2025). SOD1 mutations, first identified in familial ALS by Rosen et al. in 1993, account for approximately 13 to 20 percent of familial ALS cases and 1 to 2 percent of sporadic ALS cases. Over 200 pathogenic SOD1 variants have been reported, producing a spectrum of disease phenotypes from rapidly progressive (p.A5V, median survival approximately 1 year from onset) to slowly progressive (p.D91A homozygous, median survival exceeding 10 years). The pathogenic mechanism is a toxic gain of function in which mutant SOD1 protein undergoes misfolding, aggregation, and formation of cytoplasmic inclusions in motor neurons and astrocytes, driving neurodegeneration through oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and impaired protein degradation. Tofersen addresses this mechanism directly by reducing the concentration of the causative toxic protein. The clinical development program comprises a Phase 1-2 ascending-dose trial (50 participants) establishing dose-dependent CSF SOD1 reduction of up to 36 percent at the 100 mg intrathecal dose; the Phase 3 VALOR trial (108 participants) that did not meet its primary efficacy endpoint of change in the ALS Functional Rating Scale-Revised (ALSFRS-R) at 28 weeks (difference 1.2 points, p = 0.97) but demonstrated robust reductions in CSF SOD1 protein (29 percent) and plasma neurofilament light chain (60 percent); and an open-label extension demonstrating that participants who initiated tofersen early had a statistically significant 3.5-point advantage on ALSFRS-R decline compared with those whose treatment was delayed (p = 0.03 at 52 weeks). Accelerated approval was based on the reduction in plasma neurofilament light chain as a surrogate endpoint reasonably likely to predict clinical benefit. The ongoing ATLAS trial (NCT04856982) evaluates tofersen initiation in presymptomatic SOD1 variant carriers using plasma neurofilament light chain as a biomarker trigger for randomization. Tofersen is administered intrathecally at a dose of 100 mg in 15 mL, with three loading doses at 14-day intervals followed by maintenance doses every 28 days. The estimated CSF half-life is approximately four weeks, and elimination occurs through exonuclease-mediated hydrolysis without cytochrome P450 involvement. The principal adverse events are procedure-related (pain, headache) and drug-related (CSF pleocytosis in 42 percent of treated participants, fatigue, arthralgia, myalgia). Serious neurologic adverse events including myelitis, radiculitis, papilledema with elevated intracranial pressure, and aseptic meningitis have been reported in approximately 7 percent of tofersen-treated participants. This monograph reviews the chemistry, development history, molecular mechanism, pharmacokinetics, preclinical and clinical evidence, sourcing and handling, adverse event profile, and a comparative assessment of five alternative ALS therapeutic agents against tofersen.

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  • CAD-31

    Trifluoroacetyl hydrazone geroneuroprotector with AMPK-mediated neuroprotective and neurogenic activity

    A synthetic trifluoroacetyl hydrazone derived from the curcumin scaffold via four generations of phenotypic optimization at the Salk Institute, selected for combined neuroprotective and neurogenic activity in human neural precursor cells, with preclinical efficacy in transgenic Alzheimer’s disease and accelerated-aging mouse models through AMPK-dependent modulation of fatty acid metabolism, inflammation, and acetyl-CoA homeostasis.

    Abstract

    CAD-31 (CAD-031; CAS 2071209-49-7) is a synthetic trifluoroacetyl hydrazone (molecular weight 404.31, C18H14F6N2O2) derived from the curcumin scaffold through four generations of phenotypic optimization at the Cellular Neurobiology Laboratory of the Salk Institute for Biological Studies. The compound was selected from a library of more than 200 derivatives of the parent compound J147 on the basis of superior potency in a human embryonic stem cell-derived neural precursor cell (hNPC) neurogenesis assay and retention of broad neuroprotective activity across six cell culture models of age-associated brain toxicity [1, 2]. In assays for trophic factor withdrawal, oxidative stress (oxytosis), in vitro ischemia, extracellular and intracellular amyloid-beta toxicity, and BDNF-like neurotrophic activity, CAD-31 demonstrates EC50 values in the range of 12 to 95 nanomolar, comparable to J147 in most assays and superior in the trophic factor withdrawal model [1]. Neurogenesis markers in human neural precursor cells (nestin, Pax6, doublecortin, Ki67) are elevated 2.6- to 5.2-fold relative to J147 at matched concentrations, representing the distinctive pharmacological advance of CAD-31 within the compound series [2]. The molecular mechanism of CAD-31 converges on the AMP-activated protein kinase (AMPK) signaling cascade. CAD-31 activates AMPK by phosphorylation at threonine 172 and inhibits the downstream target acetyl-CoA carboxylase 1 (ACC1) by phosphorylation at serine 79, resulting in elevated acetyl-CoA levels, reduced free fatty acid synthesis, and increased ketone body availability in the brain [1, 6]. This metabolic reprogramming is accompanied by reductions in inflammatory markers (vascular cell adhesion molecule, receptor for advanced glycation endproducts, clusterin) and increases in synaptic proteins (drebrin, activity-regulated cytoskeleton-associated protein) in hippocampal tissue of transgenic Alzheimer’s disease mice [1]. In the therapeutic APPswe/PS1deltaE9 transgenic mouse model of Alzheimer’s disease, CAD-31 administered orally at approximately 10 mg/kg/day to symptomatic 10-month-old mice for three months rescued hippocampus-dependent memory deficits in fear conditioning, Morris water maze, and elevated plus maze paradigms to wild-type control levels [1]. In rapidly aging SAMP8 mice, CAD-31 extended median lifespan by approximately 30 percent when administered in the final quarter of life, with corresponding preservation of youthful gene, protein, and metabolite expression profiles in the brain [6]. Pharmacokinetic characterization in rats demonstrates brain penetrance with a brain-to-plasma ratio of 2.8 at eight hours after oral gavage at 20 mg/kg, and maximum brain concentrations approximately tenfold higher than the in vitro EC50 values [1]. Preclinical safety screening shows no acute toxicity at 2 g/kg, no activity in hERG, Ames, or micronucleus assays, and no inhibition of five major cytochrome P450 enzymes at concentrations more than tenfold above the effective range [1]. No formal molecular target has been identified for CAD-31; the parent compound J147 binds the alpha-F1 subunit of mitochondrial ATP synthase (ATP5A), and CAD-31 likely engages the same or a closely related target given the shared downstream AMPK activation and neuroprotective phenotype [7, 8]. CAD-31 has not entered human clinical trials. The parent compound J147 completed a Phase 1 safety study (NCT03838185), and the related compound CMS121 has received National Institutes of Health funding for Investigational New Drug studies [5]. This monograph reviews the chemistry and synthesis lineage, molecular pharmacology, preclinical pharmacokinetics, in vivo efficacy in transgenic Alzheimer’s disease and accelerated-aging models, the safety profile, and a comparative assessment of five compounds in the geroneuroprotector and Alzheimer’s disease therapeutic landscape against CAD-31. The compound is available as a research-grade preparation from multiple chemical suppliers; it has no approved medical indication in any jurisdiction.

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  • Traxoprodil

    NR2B subunit-selective N-methyl-D-aspartate receptor antagonist

    A second-generation phenylethanol amine ifenprodil derivative developed at Pfizer as a forebrain-selective neuroprotectant, distinguished from first-generation NR2B antagonists by absence of alpha-1 adrenergic receptor activity and clinically evaluated in traumatic brain injury, treatment-resistant major depression, and levodopa-induced dyskinesia in Parkinson’s disease.

    Abstract

    Traxoprodil (CP-101,606) is a potent and selective antagonist of N-methyl-D-aspartate (NMDA) receptors containing the NR2B (GluN2B) subunit, originally synthesized at the Central Research Division of Pfizer Inc. in Groton, Connecticut, and first disclosed by Chenard et al. in 1995 as a neuroprotectant with high selectivity for forebrain neurons. Structurally a substituted 4-phenylpiperidine and single-isomer phenylethanol amine derivative of the first-generation NR2B antagonist ifenprodil, traxoprodil retains the high-affinity NR2B binding (KD of 4.2 nanomolar in adult rodent forebrain) while eliminating the alpha-1 adrenergic receptor activity that limited the clinical utility of its predecessor. The compound binds at the amino-terminal domain interface of the NR1/NR2B heterodimer and inhibits channel opening by enhancing tonic proton inhibition, a mechanism formally characterized by Mott et al. (1998) that distinguishes the phenylethanol amine class from channel-blocking NMDA antagonists such as ketamine and memantine. Pharmacokinetics in humans are dominated by hepatic cytochrome P450 2D6 (CYP2D6) metabolism, producing a striking polymorphic phenotype: in CYP2D6 extensive metabolizers, the oral bioavailability at a 100 mg dose is approximately 39.5 percent with a plasma elimination half-life of 2 to 4 hours, whereas in poor metabolizers the bioavailability approaches 80 percent with a half-life of approximately 20 hours. The nonlinear, dose-dependent oral pharmacokinetics in extensive metabolizers reflect saturation of hepatic first-pass CYP2D6 metabolism; at high oral doses the impact of CYP2D6 polymorphism on exposure diminishes as the enzyme saturates. The compound was advanced through three principal clinical programs. In traumatic brain injury, an open-label study of 30 patients with severe head injury or spontaneous intracerebral hemorrhage demonstrated safety, tolerability, and 80 percent good recovery at 3 months; a subsequent randomized, double-blind, placebo-controlled Phase 2/3 trial of 404 severe TBI patients showed trends toward improved functional outcome (7.5 percent improvement on the dichotomized Glasgow Outcome Scale, p = 0.07) and reduced mortality (7 percent difference, p = 0.08) but did not reach conventional statistical significance. In treatment-resistant major depression, a randomized, double-blind, placebo-controlled proof-of-concept trial of 30 paroxetine-nonresponders demonstrated a 60 percent response rate on the Hamilton Depression Rating Scale after a single intravenous infusion of CP-101,606 versus 20 percent on placebo, with 78 percent of responders maintaining response for at least one week, and without dissociative side effects. In Parkinson’s disease, a double-blind crossover trial in 12 patients showed approximately 30 percent reduction in levodopa-induced dyskinesia but dose-dependent dissociative and amnestic adverse events. Clinical development was ultimately discontinued due to cardiovascular safety concerns, specifically QTc interval prolongation attributed to inhibition of the human ether-a-go-go-related gene (hERG) potassium channel, a liability that Pfizer determined precluded further advancement. This monograph reviews the chemistry and stereochemistry of traxoprodil; the NR2B-selective pharmacology including the proton-enhancing mechanism and the two-class distinction among NR2B antagonists; the comprehensive CYP2D6-dependent human pharmacokinetics; the preclinical neuroprotection, antinociception, antiparkinsonian, and antidepressant pharmacology; the clinical evidence across traumatic brain injury, treatment-resistant depression, and Parkinson’s disease; and a comparative assessment of five NR2B-selective or NMDA-targeting compounds (rislenemdaz, ifenprodil, Ro 25-6981, radiprodil, and ketamine) against traxoprodil on five competency standards. The compound is not approved by any regulatory authority for any indication. It is available as a research-grade preparation; investigators should obtain analytical confirmation of identity and purity on every lot.

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  • CMS121

    Geroneuroprotective small molecule; synthetic fisetin derivative; fatty acid synthase inhibitor with anti-ferroptotic and anti-inflammatory activity

    A synthetic quinoline derivative of the flavonoid fisetin, developed at the Salk Institute through phenotypic screening against age-associated neuronal cell death, that inhibits fatty acid synthase and acetyl-CoA carboxylase 1 to protect against ferroptotic lipid peroxidation and cognitive decline in transgenic Alzheimer’s disease and accelerated aging mouse models, with Phase 1 human pharmacokinetic data completed in 2022.

    Abstract

    CMS121 (CAS 1353224-53-9) is a synthetic quinoline derivative of the dietary flavonoid fisetin (3,7,3′,4′-tetrahydroxyflavone), identified through a phenotypic screening cascade at the Salk Institute for Biological Studies as a potent inhibitor of oxytotic/ferroptotic neuronal cell death with nanomolar protective activity in glutamate toxicity and iodoacetic acid toxicity assays in the HT22 hippocampal cell line. The compound was selected from more than 160 synthetic fisetin derivatives prepared by Chiruta, Schubert, Dargusch, and Maher (Journal of Medicinal Chemistry, 2012) through a multitiered screening approach that evaluated neuroprotective potency, anti-inflammatory activity, and oral pharmacokinetic suitability. The molecular target of CMS121 was subsequently identified as fatty acid synthase (FASN), with dose-dependent enzymatic inhibition demonstrated in cell lysate assays (Ates, Goldberg, Currais, and Maher, Redox Biology, 2020). Downstream of FASN inhibition, CMS121 engages the AMP-activated protein kinase/acetyl-CoA carboxylase 1 (AMPK/ACC1) axis, elevating intracellular acetyl-CoA levels and promoting histone H3 lysine 9 acetylation, a modification linked to memory enhancement in the senescence-accelerated mouse prone 8 (SAMP8) model (Currais et al., eLife, 2019). The anti-ferroptotic mechanism operates through reduction of polyunsaturated fatty acid substrates available for lipid peroxidation, thereby decreasing 4-hydroxynonenal protein adduct accumulation and suppressing downstream neuroinflammatory cascades including inducible nitric oxide synthase, cyclooxygenase-2, and tumor necrosis factor-alpha expression in activated microglia. Preclinical efficacy has been demonstrated across multiple disease models: in APPswe/PS1deltaE9 double transgenic Alzheimer’s disease mice, dietary CMS121 at 400 parts per million (approximately 34 mg/kg/day) for three months beginning at nine months of age normalized spatial memory, contextual fear conditioning, and hippocampal lipid peroxidation markers to wild-type levels; in SAMP8 accelerated aging mice, four months of treatment preserved cognition and reduced transcriptional markers of brain aging; in R6/2 and YAC128 Huntington’s disease models, CMS121 slowed motor dysfunction and extended median lifespan by up to 17 percent; and in db/db leptin receptor deficient mice and wild-type C57BL/6 mice, the compound ameliorated metabolic dysfunction, reduced adiposity, and improved hepatic and renal biomarkers. The compound was advanced to a first-in-human Phase 1 clinical trial (NCT05318040) by Virogenics, Inc. in collaboration with the National Institute on Aging, conducted at Celerion (Lincoln, Nebraska) in 2022. Single ascending doses up to 1800 mg and multiple ascending doses up to 900 mg per day for seven days were generally well tolerated in approximately 88 healthy volunteers, with the majority of treatment-emergent adverse events mild in severity. Pharmacokinetics were dose-proportional or slightly greater than dose-proportional; the CMS121-C2 metabolite was the predominant circulating species; urinary excretion was minimal; systemic exposure was approximately 50 percent higher in the fed state; and elderly subjects exhibited higher exposures and longer terminal elimination half-lives than young adults (Maher, Christopher, Evans, and Raschke, medRxiv, 2025, preprint). This monograph reviews the chemistry and structural relationship to fisetin; the FASN/ACC1/AMPK molecular pharmacology; the preclinical evidence base across Alzheimer’s disease, Huntington’s disease, aging, and metabolic models; the Phase 1 human pharmacokinetic and safety data; sourcing and handling considerations for research applications; and a comparative assessment of five related compounds (fisetin, J147, CAD031, denifanstat, and ferrostatin-1) against CMS121 on five competency standards. The compound has not received regulatory approval for any therapeutic indication. It is positioned as a research-grade geroneuroprotector for investigational use.

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  • Danavorexton

    Selective orexin 2 receptor agonist (nonpeptide, intravenous piperidine carbamate)

    A selective nonpeptide orexin 2 receptor agonist developed at Takeda Pharmaceutical Company, the first small-molecule OX2R agonist to achieve clinical proof of concept for orexin replacement therapy across narcolepsy type 1 and type 2, idiopathic hypersomnia, obstructive sleep apnea, and opioid-induced respiratory depression.

    Abstract

    Danavorexton (TAK-925) is a potent, selective, brain-penetrant, nonpeptide orexin 2 receptor (OX2R) agonist developed by Takeda Pharmaceutical Company as the first small-molecule orexin receptor agonist to enter clinical development. Identified through high-throughput screening and optimized through a medicinal chemistry campaign that converted a micromolar-potency hit (EC50 570 nM) into a low-nanomolar agonist (EC50 5.5 nM in calcium mobilization assays) with greater than 18,000-fold selectivity for human OX2R over OX1R, danavorexton is a (2R,3S)-piperidine carbamate bearing a cis-4-phenylcyclohexyl ether and a methylsulfonamide pharmacophore. The compound adopts a compact U-shaped conformation that engages the OX2R orthosteric pocket through a critical hydrogen bond between the sulfonamide nitrogen and Gln134(3.32), as resolved by two cryo-electron microscopy structures of the OX2R-G protein complex at 3.2 to 3.3 angstrom resolution. Selectivity over OX1R arises from subtle differences at only two residues (Thr111(2.61) and Thr135(3.33) in OX2R versus Ser and Ala at the corresponding positions in OX1R) that alter steric complementarity and desolvation within the orthosteric pocket. Administered exclusively by intravenous infusion, danavorexton has completed Phase 1 clinical studies in narcolepsy type 1, narcolepsy type 2, idiopathic hypersomnia, obstructive sleep apnea with residual excessive daytime sleepiness, and opioid-induced respiratory depression, collectively enrolling over 150 participants across six registered trials. In a multiple-rising-dose study (NCT03748979), danavorexton at 44 mg intravenous over 9 hours produced maximal Maintenance of Wakefulness Test sleep latency (40 minutes in all sessions) in all narcolepsy type 1 participants, reduced cataplexy episodes to zero during infusion, and normalized the Epworth Sleepiness Scale score from a baseline of 18.6 to 0.0 by day 7. Comparable wakefulness-promoting effects were demonstrated in narcolepsy type 2, idiopathic hypersomnia (placebo-adjusted sleep latency improvement of 29.4 minutes), and sleep-deprived healthy volunteers (sleep latency of 31.8 minutes at 112 mg versus 9.2 minutes on placebo). In a crossover study of remifentanil-induced respiratory depression, danavorexton reversed respiratory depression (minute volume increase of 13.0 L/min at 19 mg, p < 0.001) and sedation without reversing opioid analgesia. Human pharmacokinetics are characterized by dose-proportional plasma concentrations, a terminal half-life of approximately 3 to 5 hours, negligible accumulation with daily 9-hour infusions, and a cerebrospinal fluid-to-plasma concentration ratio of approximately 2.8 percent. The compound is well tolerated across all studied populations. The most common drug-related adverse events are pollakiuria (urinary frequency), transient blood pressure elevation, insomnia, headache, and dizziness, all predominantly mild in severity. No hepatotoxicity has been observed, distinguishing danavorexton from its oral successor TAK-994 (firazorexton), which demonstrated exceptional efficacy in a Phase 2 narcolepsy trial but was discontinued following drug-induced liver injury in three participants meeting Hy's law criteria. The second-generation oral OX2R agonist TAK-861 (oveporexton), structurally distinct from both danavorexton and TAK-994, has completed a positive Phase 2 trial with no hepatic signal and is advancing toward Phase 3 registration. This monograph reviews the medicinal chemistry, structural biology, receptor pharmacology, pharmacokinetics, preclinical and clinical evidence base, adverse event profile, sourcing and handling considerations, and a comparative assessment of danavorexton against four alternative agents in the narcolepsy and excessive daytime sleepiness pharmacotherapy space (TAK-994, TAK-861, pitolisant, solriamfetol) on five competency standards. Danavorexton is not approved for any indication in any jurisdiction. It is an investigational compound available in research-grade preparations; investigators should obtain analytical confirmation of identity and purity on every lot.

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  • Elamipretide

    Mitochondria-targeted aromatic-cationic tetrapeptide that binds cardiolipin in the inner mitochondrial membrane

    A first-in-class cardiolipin-binding tetrapeptide developed by Szeto and Schiller that stabilizes mitochondrial cristae architecture, restores electron transport chain supercomplex function, and received FDA accelerated approval for Barth syndrome as the first mitochondria-targeted peptide therapeutic.

    Abstract

    Elamipretide (D-Arg-2′,6′-dimethylTyr-Lys-Phe-NH2; also designated SS-31, MTP-131, and Bendavia) is a synthetic aromatic-cationic tetrapeptide that concentrates more than 1000-fold in the inner mitochondrial membrane, where it binds cardiolipin and modulates membrane surface electrostatics to stabilize cristae architecture, optimize electron transport chain supercomplex assembly, and reduce reactive oxygen species generation at the mitochondrial source. Discovered fortuitously by Hazel Szeto and Peter Schiller during opioid receptor research, the compound was characterized in a foundational 2004 report demonstrating nanomolar-range cytoprotection against oxidative cell death and reperfusion injury in isolated mitochondria and ex vivo cardiac tissue. Biophysical studies by Mitchell et al. (2020) have since established that the primary mechanism is not stoichiometric antioxidant scavenging but rather electrostatic modulation of anionic lipid bilayer properties: SS-31 partitions into the membrane interfacial region with a dissociation constant of 2.0 to 2.9 micromolar for cardiolipin-containing membranes, saturably reduces surface potential, and decreases interfacial divalent cation accumulation by over an order of magnitude; these effects are independent of mitochondrial membrane potential. In freshly explanted failing human heart tissue, elamipretide at 100 micromolar selectively restored Complex I-driven oxygen flux, supercomplex coupling, and respiratory control ratio without affecting non-failing hearts, confirming a disease-selective mechanism operating through cardiolipin-protein interaction stabilization rather than cardiolipin remodeling. Stealth BioTherapeutics advanced elamipretide through clinical programs in Barth syndrome (TAZPOWER), primary mitochondrial myopathy (MMPOWER series), heart failure with reduced ejection fraction (PROGRESS-HF, EMBRACE-STEMI), and dry age-related macular degeneration (ReCLAIM series). The Barth syndrome program, conducted in patients with tafazzin gene mutations and defective cardiolipin remodeling, demonstrated sustained improvements in six-minute walk distance (cumulative 96.1 meters at 168 weeks, P = 0.003) and knee extensor muscle strength in the open-label extension, leading to FDA accelerated approval in September 2025 under the brand name FORZINITY for improvement of muscle strength in adult and pediatric patients weighing at least 30 kilograms. The 12-week randomized crossover portion of TAZPOWER did not meet its primary endpoints, and the pivotal Phase 3 trial in primary mitochondrial myopathy (MMPOWER-3, n = 218) did not meet co-primary endpoints on six-minute walk test and fatigue score, though post hoc analysis identified a responding subgroup with nuclear DNA replisome pathogenic variants and chronic progressive external ophthalmoplegia phenotype. Heart failure and macular degeneration trials similarly did not meet primary endpoints, though exploratory signals in cardiac volume reduction and ellipsoid zone preservation were observed. Pharmacokinetically, elamipretide is administered as a 40 mg subcutaneous injection once daily, with absolute bioavailability of approximately 92 percent, time to peak concentration of 0.5 to 1 hour, plasma elimination half-life of approximately 3 to 4 hours, and exclusively renal elimination with no hepatic metabolism and no cytochrome P450 interactions. This monograph reviews the chemistry and structure, discovery history, cardiolipin-binding pharmacology, pharmacokinetics, preclinical evidence across cardiac, renal, neuroinflammatory, and aging models, the complete clinical trial inventory across all studied indications, sourcing and quality verification, handling, drug interactions, adverse event profile, and a comparative assessment of five mitochondrial therapeutics (idebenone, omaveloxolone, MitoQ, vatiquinone, and coenzyme Q10) against elamipretide on five competency standards.

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  • Fasudil

    Isoquinolinesulfonamide Rho-associated protein kinase (ROCK) inhibitor with vasodilatory, anti-inflammatory, and neuroprotective activity

    An isoquinolinesulfonamide kinase inhibitor developed by Asahi Kasei as the first clinically approved ROCK inhibitor, registered in Japan and China for cerebral vasospasm after subarachnoid hemorrhage, with expanding investigational applications in pulmonary hypertension, amyotrophic lateral sclerosis, and cardiovascular disease.

    Abstract

    Fasudil (HA-1077, AT-877), the isoquinolinesulfonamide derivative of the H-series protein kinase inhibitors first described by Hidaka et al. in 1984, is the only Rho-associated coiled-coil-containing protein kinase (ROCK) inhibitor approved for systemic clinical use and the first protein kinase inhibitor to receive regulatory approval for any indication. Developed by Asahi Kasei Pharma (Tokyo, Japan) and marketed as Eril, fasudil has been approved in Japan since 1995 and in China for the treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage, where it is standard of care in Japanese neurosurgical practice. The compound inhibits ROCK by competitive occupation of the ATP-binding domain, with a Ki of approximately 0.33 micromolar against ROCK activity and modest preferential selectivity for ROCK2 (Ki approximately 47 nanomolar) over ROCK1 (Ki approximately 76 nanomolar) in purified kinase assays. Off-target inhibition of protein kinase A, protein kinase G, protein kinase C, and myosin light chain kinase occurs at approximately 5- to 100-fold higher concentrations. The principal metabolic transformation is rapid hepatic conversion to hydroxyfasudil by aldehyde oxidase (not cytochrome P450), producing an active metabolite with ROCK inhibitory potency similar to or greater than the parent compound and a substantially longer plasma half-life (approximately 5.5 hours versus 0.55 hours for fasudil). This metabolic profile renders fasudil effectively a prodrug of hydroxyfasudil in the oral context. The clinical evidence base in cerebral vasospasm rests on a pivotal 267-patient double-blind placebo-controlled trial (Shibuya et al. 1992) demonstrating significant reductions in angiographic vasospasm (38 versus 61 percent), symptomatic vasospasm (35 versus 50 percent), and poor outcome on the Glasgow Outcome Scale (12 versus 26 percent), confirmed by a 1,462-patient postmarketing surveillance study and a meta-analysis of 8 trials (odds ratio 0.48 for symptomatic vasospasm). Head-to-head comparison with nimodipine demonstrated comparable or superior outcomes (74.5 versus 61.7 percent good clinical outcome). Expanding investigational programs span pulmonary arterial hypertension, where meta-analyses of up to 865 patients demonstrate significant reductions in pulmonary artery pressure, vascular resistance, and 6-minute walk distance with no serious adverse events; and amyotrophic lateral sclerosis, where the 120-patient ROCK-ALS Phase 2 trial confirmed safety, demonstrated significant electrophysiological biomarker preservation (motor unit number index), and confirmed cerebrospinal fluid penetration of the active metabolite at concentrations matching preclinical efficacy. This monograph reviews the chemistry, synthesis, and structure-activity relationships of fasudil; the kinase inhibition profile and downstream signaling including ROCK-mediated myosin light chain phosphorylation, NF-kappaB inflammatory signaling, PPARalpha-NOX neuroprotective axis, and microglial modulation; the comprehensive pharmacokinetics of fasudil and hydroxyfasudil from the first formal Phase I oral bioavailability study; the preclinical evidence across cerebrovascular, cardiovascular, spinal cord injury, and neurodegenerative disease models; the full clinical evidence base across cerebral vasospasm, pulmonary hypertension, amyotrophic lateral sclerosis, and coronary vasospasm indications; and a comparative assessment against four ROCK inhibitor comparators (Y-27632, ripasudil, netarsudil, belumosudil) and the calcium channel blocker nimodipine. Fasudil is approved only in Japan and China. It is available as a research-grade preparation from established chemical suppliers; investigators should obtain analytical confirmation of identity and purity on every lot.

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