RESUMEN
This article outlines the process development leading to the manufacture of 800 g of BMS-986189, a macrocyclic peptide active pharmaceutical ingredient. Multiple N-methylated unnatural amino acids posed challenges to manufacturing due to the lability of the peptide to cleavage during global side chain deprotection and precipitation steps. These issues were exacerbated upon scale-up, resulting in severe yield loss and necessitating careful impurity identification, understanding the root cause of impurity formation, and process optimization to deliver a scalable synthesis. A systematic study of macrocyclization with its dependence on concentration and pH is presented. In addition, a side chain protected peptide synthesis is discussed where the macrocyclic protected peptide is extremely labile to hydrolysis. A computational study explains the root cause of the increased lability of macrocyclic peptide over linear peptide to hydrolysis. A process solution involving the use of labile protecting groups is discussed. Overall, the article highlights the advancements achieved to enable scalable synthesis of an unusually labile macrocyclic peptide by solid-phase peptide synthesis. The sustainability metric indicates the final preparative chromatography drives a significant fraction of a high process mass intensity (PMI).
Asunto(s)
Compuestos Macrocíclicos , Compuestos Macrocíclicos/química , Compuestos Macrocíclicos/síntesis química , Péptidos Cíclicos/química , Péptidos Cíclicos/síntesis química , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/química , Péptidos/química , Péptidos/síntesis química , Técnicas de Síntesis en Fase Sólida , Estructura MolecularRESUMEN
We describe an optimization and scale-up of the 45-membered macrocyclic thioether peptide BMS-986189 utilizing solid-phase peptide synthesis (SPPS). Improvements to linear peptide isolation, macrocyclization, and peptide purification were demonstrated to increase the throughput and purification of material on scale and enabled the synthesis and purification of >60 g of target peptide. Taken together, not only these improvements resulted in a 28-fold yield increase from the original SPPS approach, but also the generality of this newly developed SPPS purification sequence has found application in the synthesis and purification of other macrocyclic thioether peptides.
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Compuestos Macrocíclicos , Péptidos , Técnicas de Síntesis en Fase Sólida , Sulfuros , Sulfuros/química , Sulfuros/síntesis química , Compuestos Macrocíclicos/química , Compuestos Macrocíclicos/síntesis química , Péptidos/química , Péptidos/síntesis química , Péptidos Cíclicos/química , Péptidos Cíclicos/síntesis química , Estructura Molecular , CiclizaciónRESUMEN
A simple and expeditious method for the regioselective synthesis of N1-substituted-4-nitropyrazole-5-carboxylates was developed. The method involves cyclocondensation of ethyl 4-(dimethylamino)-3-nitro-2-oxobut-3-enoate with a series of monosubstituted hydrazines to give N1-substituted-4-nitropyrazole-5-carboxylates with excellent regioselectivity and good yields. Solvent effects on regioselectivity of the cyclocondensation were examined.
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Ácidos Carboxílicos , Hidrazinas , CiclizaciónRESUMEN
Indole and indoline rings are important pharmacophoric scaffolds found in marketed drugs, agrochemicals, and biologically active molecules. The [2 + 2] cycloaddition reaction is a versatile strategy for constructing architecturally interesting, sp3-rich cyclobutane-fused scaffolds with potential applications in drug discovery programs. A general platform for visible-light mediated intermolecular [2 + 2] cycloaddition of indoles with alkenes has been realized. A substrate-based screening approach led to the discovery of tert-butyloxycarbonyl (Boc)-protected indole-2-carboxyesters as suitable motifs for the intermolecular [2 + 2] cycloaddition reaction. Significantly, the reaction proceeds in good yield with a wide variety of both activated and unactivated alkenes, including those containing free amines and alcohols, and the transformation exhibits excellent regio- and diastereoselectivity. Moreover, the scope of the indole substrate is very broad, extending to previously unexplored azaindole heterocycles that collectively afford fused cyclobutane containing scaffolds that offer unique properties with functional handles and vectors suitable for further derivatization. DFT computational studies provide insights into the mechanism of this [2 + 2] cycloaddition, which is initiated by a triplet-triplet energy transfer process. The photocatalytic reaction was successfully performed on a 100 g scale to provide the dihydroindole analog.
RESUMEN
We describe a stereodefined synthesis of the newly identified non-natural phosphorothioate cyclic dinucleotide (CDN) STING agonist, BMT-390025. The new route avoids the low-yielding racemic approach using P(III)-based reagents, and the stereospecific assembly of the phosphorothioate linkages are forged via the recently invented P(V)-based platform of the so-called PSI (Ψ) reagent system. This P(V) approach allows for the complete control of chirality of the P-based linkages and enabled conclusive evidence of the absolute configuration. The new approach offers robust procedures for preparing the stereodefined CDN in eight steps starting from advanced nucelosides, with late-stage direct drop isolations and telescoped steps enabling an efficient scale-up that proceeded in an overall 15% yield to produce multigram amounts of the CDN.
RESUMEN
We describe the synthesis through visible-light photocatalysis of novel functionalized tetracyclic scaffolds that incorporate a fused azabicyclo[3.2.0]heptan-2-one motif, which are structurally interesting cores with potential in natural product synthesis and drug discovery. The synthetic approach involves an intramolecular [2 + 2] cycloaddition with concomitant dearomatization of the heterocycle via an energy transfer process promoted by an iridium-based photosensitizer, to build a complex molecular architecture with at least three stereogenic centers from relatively simple, achiral precursors. These fused azabicyclo[3.2.0]heptan-2-one-based tetracycles were obtained in high yield (generally >99%) and with excellent diastereoselectivity (>99:1). The late-stage derivatization of a bromine-substituted, tetracyclic indoline derivative with alkyl groups, employing a mild Negishi C-C bond forming protocol as a means of increasing structural diversity, provides additional modularity that will enable the delivery of valuable building blocks for medicinal chemistry. Density functional theory calculations were used to compute the T1-S0 free energy gap of the olefin-tethered precursors and also to predict their reactivities based on triplet state energy transfer and transition state energy feasibility.
RESUMEN
We describe an efficient synthetic route to differentially protected diester, 1-(tert-butyl) 4-methyl (1R,2S,4R)-2-methylcyclohexane-1,4-dicarboxylate (+)-1, via palladium-catalyzed methoxycarbonylation of an enol triflate derived from a Hagemann's ester derivative followed by a stereoselective Crabtree hydrogenation. Diester 1 is a novel chiral synthon useful in drug discovery and was instrumental in the generation of useful SAR during a RORγt inverse agonist program. In addition, we describe a second-generation synthesis of the clinical candidate BMS-986251, using diester 1 as a critical component.
Asunto(s)
Ácidos Carboxílicos , Ésteres , Ciclohexanos , EstereoisomerismoRESUMEN
(R)-3-((3S,4S)-3-fluoro-4-(4-hydroxyphenyl)piperidin-1-yl)-1-(4-methylbenzyl)pyrrolidin-2-one (BMS-986169) and the phosphate prodrug 4-((3S,4S)-3-fluoro-1-((R)-1-(4-methylbenzyl)-2-oxopyrrolidin-3-yl)piperidin-4-yl)phenyl dihydrogen phosphate (BMS-986163) were identified from a drug discovery effort focused on the development of novel, intravenous glutamate N-methyl-d-aspartate 2B receptor (GluN2B) negative allosteric modulators (NAMs) for treatment-resistant depression (TRD). BMS-986169 showed high binding affinity for the GluN2B subunit allosteric modulatory site (Ki = 4.03-6.3 nM) and selectively inhibited GluN2B receptor function in Xenopus oocytes expressing human N-methyl-d-aspartate receptor subtypes (IC50 = 24.1 nM). BMS-986169 weakly inhibited human ether-a-go-go-related gene channel activity (IC50 = 28.4 µM) and had negligible activity in an assay panel containing 40 additional pharmacological targets. Intravenous administration of BMS-986169 or BMS-986163 dose-dependently increased GluN2B receptor occupancy and inhibited in vivo [3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine ([3H]MK-801) binding, confirming target engagement and effective cleavage of the prodrug. BMS-986169 reduced immobility in the mouse forced swim test, an effect similar to intravenous ketamine treatment. Decreased novelty suppressed feeding latency, and increased ex vivo hippocampal long-term potentiation was also seen 24 hours after acute BMS-986163 or BMS-986169 administration. BMS-986169 did not produce ketamine-like hyperlocomotion or abnormal behaviors in mice or cynomolgus monkeys but did produce a transient working memory impairment in monkeys that was closely related to plasma exposure. Finally, BMS-986163 produced robust changes in the quantitative electroencephalogram power band distribution, a translational measure that can be used to assess pharmacodynamic activity in healthy humans. Due to the poor aqueous solubility of BMS-986169, BMS-986163 was selected as the lead GluN2B NAM candidate for further evaluation as a novel intravenous agent for TRD.
Asunto(s)
Antidepresivos/uso terapéutico , Trastorno Depresivo Mayor/tratamiento farmacológico , Organofosfatos/uso terapéutico , Piperidinas/uso terapéutico , Profármacos/uso terapéutico , Pirrolidinonas/uso terapéutico , Receptores de N-Metil-D-Aspartato/metabolismo , Administración Intravenosa , Regulación Alostérica , Animales , Antidepresivos/efectos adversos , Antidepresivos/farmacocinética , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/fisiopatología , Ondas Encefálicas/efectos de los fármacos , Trastorno Depresivo Mayor/fisiopatología , Trastorno Depresivo Mayor/psicología , Trastornos Disociativos/inducido químicamente , Macaca fascicularis , Masculino , Memoria a Corto Plazo/efectos de los fármacos , Ratones , Actividad Motora/efectos de los fármacos , Organofosfatos/efectos adversos , Organofosfatos/farmacocinética , Piperidinas/efectos adversos , Piperidinas/farmacocinética , Profármacos/efectos adversos , Profármacos/farmacocinética , Pirrolidinonas/efectos adversos , Pirrolidinonas/farmacocinética , Ensayo de Unión Radioligante , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , XenopusRESUMEN
The identification of small molecule inhibitors of IRAK4 for the treatment of autoimmune diseases has been an area of intense research. We discovered novel 4,6-diaminonicotinamides which potently inhibit IRAK4. Optimization efforts were aided by X-ray crystal structures of inhibitors bound to IRAK4. Structure activity relationship (SAR) studies led to the identification of compound 29 which exhibited sub-micromolar potency in a LTA stimulated cellular assay.
Asunto(s)
Diseño de Fármacos , Quinasas Asociadas a Receptores de Interleucina-1/antagonistas & inhibidores , Niacinamida/química , Inhibidores de Proteínas Quinasas/química , Sitios de Unión , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Humanos , Concentración 50 Inhibidora , Quinasas Asociadas a Receptores de Interleucina-1/metabolismo , Janus Quinasa 3/química , Janus Quinasa 3/metabolismo , Conformación Molecular , Simulación de Dinámica Molecular , Niacinamida/metabolismo , Inhibidores de Proteínas Quinasas/metabolismo , Estructura Terciaria de Proteína , Relación Estructura-ActividadRESUMEN
A series of potent dual JAK1/3 inhibitors have been developed from a moderately selective JAK3 inhibitor. Substitution at the C6 position of the pyrrolopyridazine core with aryl groups provided exceptional biochemical potency against JAK1 and JAK3 while maintaining good selectivity against JAK2 and Tyk2. Translation to in vivo efficacy was observed in a murine model of chronic inflammation. X-ray co-crystal structure determination confirmed the presumed inhibitor binding orientation in JAK3. Efforts to reduce hERG channel inhibition will be described.
Asunto(s)
Janus Quinasa 1/antagonistas & inhibidores , Janus Quinasa 3/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Piridazinas/química , Pirroles/química , Animales , Sitios de Unión , Dominio Catalítico , Línea Celular , Cristalografía por Rayos X , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Inflamación/prevención & control , Concentración 50 Inhibidora , Janus Quinasa 1/metabolismo , Janus Quinasa 2/antagonistas & inhibidores , Janus Quinasa 2/metabolismo , Janus Quinasa 3/metabolismo , Ratones , Ratones Endogámicos BALB C , Conformación Molecular , Simulación de Dinámica Molecular , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Piridazinas/síntesis química , Piridazinas/farmacocinética , Pirroles/síntesis química , Pirroles/farmacocinética , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , TYK2 Quinasa/antagonistas & inhibidores , TYK2 Quinasa/metabolismoRESUMEN
A useful and novel set of tool molecules have been identified which bind irreversibly to the JAK3 active site cysteine residue. The design was based on crystal structure information and a comparative study of several electrophilic warheads.
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Janus Quinasa 3/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Sitios de Unión , Dominio Catalítico , Línea Celular , Supervivencia Celular/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Humanos , Concentración 50 Inhibidora , Janus Quinasa 1/antagonistas & inhibidores , Janus Quinasa 1/metabolismo , Janus Quinasa 2/antagonistas & inhibidores , Janus Quinasa 2/metabolismo , Janus Quinasa 3/metabolismo , Simulación del Acoplamiento Molecular , Inhibidores de Proteínas Quinasas/metabolismo , Relación Estructura-ActividadRESUMEN
The synthesis and structure-activity relationship (SAR) of a series of pyridyl-isoxazole based agonists of S1P1 are discussed. Compound 5b provided potent in vitro activity with selectivity, had an acceptable pharmacokinetic profile, and demonstrated efficacy in a dose dependent manner when administered orally in a rodent model of arthritis.
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Artritis Experimental/tratamiento farmacológico , Lisofosfolípidos/agonistas , Esfingosina/análogos & derivados , Relación Estructura-Actividad , Administración Oral , Animales , Técnicas de Química Sintética , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos/métodos , Humanos , Isoxazoles/química , Isoxazoles/farmacología , Recuento de Linfocitos , Masculino , Ratas Endogámicas Lew , Receptores de Lisoesfingolípidos/agonistas , Esfingosina/agonistasRESUMEN
A macrocyclic peptide A was successfully purified in large quantities (â¼30 g) in >95 % purity by an integrated two-step orthogonal purification process combining supercritical fluid chromatography (SFC) with medium-pressure reverse-phase liquid chromatography (MP-RPLC). MP-RPLC was used to fractionate the crude peptide A, remove unwanted trifluoroacetic acid (TFA) originating from the peptide A cleavage off the resin, and convert the peptide A into ammonium acetate salt form, prior to the final purification by SFC. A co-solvent of methanol/acetonitrile containing ammonium acetate and water in CO2 was developed on a Waters BEH 2-Ethylpyridine column. The developed SFC method was readily scaled up onto a 5 cm diameter column to process multi-gram quantities of the MP-RPLC fraction to reach > 95 % purity with a throughput/productivity of 0.96 g/h. The incorporation of SFC with MP-RPLC has been demonstrated to have a broader application in other large-scale polypeptide purifications.
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Cromatografía de Fase Inversa , Cromatografía con Fluido Supercrítico , Cromatografía con Fluido Supercrítico/métodos , Cromatografía de Fase Inversa/métodos , Acetatos/química , Ácido Trifluoroacético/química , Péptidos Cíclicos/química , Péptidos Cíclicos/aislamiento & purificación , Acetonitrilos/química , Metanol/químicaRESUMEN
GSK3640254 is an HIV-1 maturation inhibitor (MI) that exhibits significantly improved antiviral activity toward a range of clinically relevant polymorphic variants with reduced sensitivity toward the second-generation MI GSK3532795 (BMS-955176). The key structural difference between GSK3640254 and its predecessor is the replacement of the para-substituted benzoic acid moiety attached at the C-3 position of the triterpenoid core with a cyclohex-3-ene-1-carboxylic acid substituted with a CH2F moiety at the carbon atom α- to the pharmacophoric carboxylic acid. This structural element provided a new vector with which to explore structure-activity relationships (SARs) and led to compounds with improved polymorphic coverage while preserving pharmacokinetic (PK) properties. The approach to the design of GSK3640254, the development of a synthetic route and its preclinical profile are discussed. GSK3640254 is currently in phase IIb clinical trials after demonstrating a dose-related reduction in HIV-1 viral load over 7-10 days of dosing to HIV-1-infected subjects.
Asunto(s)
Fármacos Anti-VIH , VIH-1 , Triterpenos , Humanos , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , Ácido Benzoico/química , Carbono , Triterpenos/química , Triterpenos/farmacología , Triterpenos/uso terapéuticoRESUMEN
The synthesis, structure-activity relationships (SAR) and biological evaluation of thiazole based tricyclic inhibitors of IKK2 are described. Compound 9 was determined to be orally efficacious in a murine model of rheumatoid arthritis.
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Artritis Reumatoide/tratamiento farmacológico , Quinasa I-kappa B/antagonistas & inhibidores , Imidazoles/química , Inhibidores de Proteínas Quinasas/química , Piridinas/química , Tiazoles/química , Animales , Modelos Animales de Enfermedad , Perros , Evaluación Preclínica de Medicamentos , Femenino , Quinasa I-kappa B/metabolismo , Ratones , Ratones Endogámicos BALB C , Inhibidores de Proteínas Quinasas/farmacocinética , Inhibidores de Proteínas Quinasas/uso terapéutico , Piridinas/farmacocinética , Piridinas/uso terapéutico , Ratas , Relación Estructura-ActividadRESUMEN
The synthesis, structure-activity relationships (SAR), and biological results of pyridyl-substituted azaindole based tricyclic inhibitors of IKK2 are described. Compound 4m demonstrated potent in vitro potency, acceptable pharmacokinetic and physicochemical properties, and efficacy when dosed orally in a mouse model of inflammatory bowel disease.
Asunto(s)
Acetamidas/química , Descubrimiento de Drogas , Inhibidores Enzimáticos/química , Compuestos Heterocíclicos con 3 Anillos/química , Quinasa I-kappa B/antagonistas & inhibidores , Acetamidas/síntesis química , Acetamidas/farmacología , Administración Oral , Animales , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Compuestos Heterocíclicos con 3 Anillos/síntesis química , Compuestos Heterocíclicos con 3 Anillos/farmacología , Humanos , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Ratas , Relación Estructura-ActividadRESUMEN
BMS-962212, a parenteral Factor XIa inhibitor, was scaled-up for toxicity studies. Two steps of supercritical fluid chromatography (SFC) were developed for the chiral resolution of the penultimate and achiral purification of final active pharmaceutical ingredient (API), BMS-962212. A robust SFC process using Chiralcel OD-H with methanol-acetonitrile as modifier in CO2 was established to achieve a stable and uninterrupted operation with reduced mobile phase viscosity and system pressure drop. More than 230 g of the racemic penultimate was chirally resolved to reach >99% chiral purity, ready for final tert-butyl ester deprotection to provide the API. There were a significant number of impurities in BMS-962212 generated from the final step that needed to be removed. In contrast to conventional SFC conditions, an SFC method exploiting water and ammonia as additives in both the mobile phase and sample solution was developed to accomplish purification and desalting (i.e. removing TFA) of the zwitterionic API in one step. Water as an additive eliminated salt precipitation and improved the resolution while ammonia contributed to the desalting, details of which will be discussed in this article. A throughput of 2 g/h was achieved, and >80 g of the crude API was purified. The same strategy was applied to another Factor XIa API (compound A) and its penultimate.
Asunto(s)
Cromatografía con Fluido Supercrítico/métodos , Factor XIa/aislamiento & purificación , Preparaciones Farmacéuticas/aislamiento & purificación , Agua/química , Acetonitrilos , Amoníaco/química , Cromatografía Líquida de Alta Presión , Factor XIa/química , Isoquinolinas/química , Metanol/química , Preparaciones Farmacéuticas/química , Estereoisomerismo , para-Aminobenzoatos/químicaRESUMEN
A regioisomeric mixture of the nucleoside derivative, Intermediate 1, required resolution by preparative supercritical fluid chromatography (SFC) in order to obtain the desired regioisomer as a key intermediate in a STING agonist program. Various chiral columns and solvents including methanol, acetonitrile, isopropanol, and the mixture of acetonitrile and isopropanol as organic modifiers in carbon dioxide at different temperatures were screened to obtain the best regioisomeric resolution. A key issue associated with interconversion between the regioisomers via silyl migration during purification was investigated in methanol, acetonitrile, and the mixture of acetonitrile and isopropanol, and the optimal organic modifier in CO2 was established to mitigate the interconversion to an acceptable level (<5%). Taking into account peak resolution, throughput, interconversion and operation robustness, an efficient SFC method for large-scale purification was successfully developed and scaled up onto a 5 cm I. D. Chiralcel OJ-H column using 25% acetonitrile: isopropanol [1:1 (v/v)] with 0.1% ammonium hydroxide as the modifier in CO2 at a total flow rate of 270 mL/min and a temperature of 30°C. In addition, continual evaporation (i.e. every hour) of the desired isomer fraction stream post-separation ensured minimal further interconversion. A total of 258 grams were separated at a high throughput of 8.6 g/h. Regioisomeric purity of the desired isomer of Intermediate 1 was ≥98.2% and the recovery was ≥90.2%. A similar purification strategy was applied to the regioisomeric resolution of Intermediate 2, an analog of Intermediate 1. In total, 1028 grams of Intermediate 2 were processed at a high throughput of 12.5 g/h on a Viridis BEH 2-EP column. The regioisomeric purity of the desired isomer was ≥96.8% and the recovery was ≥90.7%.
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Adyuvantes Inmunológicos/aislamiento & purificación , Cromatografía con Fluido Supercrítico , Proteínas de la Membrana/agonistas , Adyuvantes Inmunológicos/química , Hidróxido de Amonio/química , Dióxido de Carbono/química , Proteínas de la Membrana/genética , Metanol/química , Solventes/química , Estereoisomerismo , TemperaturaRESUMEN
An efficient and "endotoxin-free" purification of a cyclic dinucleotide (CDN) STING agonist was achieved to produce multigram quantities of pure BMT-390025, an active pharmaceutical ingredient (API), for toxicological studies. A two-step sub/supercritical fluid chromatography (SFC) procedure was developed for the achiral purification and desalting of the polar ionic CDN. A robust SFC process employing methanol-acetonitrile-water with ammonium acetate as co-solvent in CO2 on BEH 2-ethylpyridine was established and scaled up as the first step to achieve a successful purification. The desalting/salt-switching (i.e. removing acetate and acetamide) was conducted using methanol-water with ammonium hydroxide as co-solvent on the same column in the second step to convert the final API to the ammonium salt. Water with additive was essential to eliminating salt precipitation and improving the peak shape and resolution. Due to the extreme hydrophilicity of BMT-390025, 65% of co-solvent was needed to adequately elute the target in both steps. More than 40 g of crude API was purified and desalted producing >20 g of pure BMT-390025 as the ammonium salt which was obtained with a chemical purity of >98.5% and met the endotoxin requirement of <0.1 EU/mg. In addition, >80 g of its penultimate prior to the deprotection of the silyl group was purified at a high throughput of 6.3 g/h (0.42 g/day/g SP).
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Cromatografía con Fluido Supercrítico/métodos , Acetamidas/química , Acetatos/química , Acetonitrilos/química , Hidróxido de Amonio/química , Interacciones Hidrofóbicas e Hidrofílicas , Metanol/química , Solventes/química , Agua/químicaRESUMEN
Inhibition of TGFß signaling in concert with a checkpoint blockade has been shown to provide improved and durable antitumor immune response in mouse models. However, on-target adverse cardiovascular effects have limited the clinical use of TGFß receptor (TGFßR) inhibitors in cancer therapy. To restrict the activity of TGFßR inhibitors to tumor tissues and thereby widen the therapeutic index, a series of tumor-activated prodrugs of a selective small molecule TGFßR1 inhibitor 1 were prepared by appending 1 to a serine protease substrate and a half-life extension fatty acid carbon chain. The prodrugs were shown to be selectively metabolized in tumor tissues relative to the heart and blood and demonstrated a prolonged favorable increase in the tumor-to-heart ratio of the active drug in tissue distribution studies. Once-weekly administration of the most tissue-selective compound 10 provided anti-tumor efficacy comparable to the parent compound and reduced systemic exposure of the active drug.