Discovery of BMS-986144, a Third-Generation, Pan-Genotype NS3/4A Protease Inhibitor for the Treatment of Hepatitis C Virus Infection.

The discovery of a pan-genotypic hepatitis C virus (HCV) NS3/4A protease inhibitor based on a P1-P3 macrocyclic tripeptide motif is described. The all-carbon tether linking the P1-P3 subsites of 21 is functionalized with alkyl substituents, which are shown to effectively modulate both potency and absorption, distribution, metabolism, and excretion (ADME) properties. The CF3Boc-group that caps the P3 amino moiety was discovered to be an essential contributor to metabolic stability, while positioning a methyl group at the C1 position of the P1' cyclopropyl ring enhanced plasma trough values following oral administration to rats. The C7-fluoro, C6-CD3O substitution pattern of the P2* isoquinoline heterocycle of 21 was essential to securing the targeted potency, pharmacokinetic (PK), and toxicological profiles. The C6-CD3O redirected metabolism away from a problematic pathway, thereby circumventing the time-dependent cytochrome P (CYP) 450 inhibition observed with the C6-CH3O prototype.

Potent Inhibitors of Hepatitis C Virus NS3 Protease: Employment of a Difluoromethyl Group as a Hydrogen-Bond Donor.

The design and synthesis of potent, tripeptidic acylsulfonamide inhibitors of HCV NS3 protease that contain a difluoromethyl cyclopropyl amino acid at P1 are described. A cocrystal structure of 18 with a NS3/4A protease complex suggests the presence of a H-bond between the polarized C-H of the CHF2 moiety and the backbone carbonyl of Leu135 of the enzyme. Structure-activity relationship studies indicate that this H-bond enhances enzyme inhibitory potency by 13- and 17-fold compared to the CH3 and CF3 analogues, respectively, providing insight into the deployment of this unique amino acid.

Discovery of BMS-961955, an allosteric inhibitor of the hepatitis C virus NS5B polymerase.

The synthesis, structure-activity relationship (SAR) data, and further optimization of the metabolic stability and pharmacokinetic (PK) properties for a previously disclosed class of cyclopropyl-fused indolobenzazepine HCV NS5B polymerase inhibitors are described. These efforts led to the discovery of BMS-961955 as a viable contingency backup to beclabuvir which was recently approved in Japan for the treatment of HCV as part of a three drug, single pill combination marketed as XimencyTM.

Discovery of a Potent Acyclic, Tripeptidic, Acyl Sulfonamide Inhibitor of Hepatitis C Virus NS3 Protease as a Back-up to Asunaprevir with the Potential for Once-Daily Dosing.

The discovery of a back-up to the hepatitis C virus NS3 protease inhibitor asunaprevir (2) is described. The objective of this work was the identification of a drug with antiviral properties and toxicology parameters similar to 2, but with a preclinical pharmacokinetic (PK) profile that was predictive of once-daily dosing. Critical to this discovery process was the employment of an ex vivo cardiovascular (CV) model which served to identify compounds that, like 2, were free of the CV liabilities that resulted in the discontinuation of BMS-605339 (1) from clinical trials. Structure-activity relationships (SARs) at each of the structural subsites in 2 were explored with substantial improvement in PK through modifications at the P1 site, while potency gains were found with small, but rationally designed structural changes to P4. Additional modifications at P3 were required to optimize the CV profile, and these combined SARs led to the discovery of BMS-890068 (29).

The discovery of asunaprevir (BMS-650032), an orally efficacious NS3 protease inhibitor for the treatment of hepatitis C virus infection.

The discovery of asunaprevir (BMS-650032, 24) is described. This tripeptidic acylsulfonamide inhibitor of the NS3/4A enzyme is currently in phase III clinical trials for the treatment of hepatitis C virus infection. The discovery of 24 was enabled by employing an isolated rabbit heart model to screen for the cardiovascular (CV) liabilities (changes to HR and SNRT) that were responsible for the discontinuation of an earlier lead from this chemical series, BMS-605339 (1), from clinical trials. The structure-activity relationships (SARs) developed with respect to CV effects established that small structural changes to the P2* subsite of the molecule had a significant impact on the CV profile of a given compound. The antiviral activity, preclincial PK profile, and toxicology studies in rat and dog supported clinical development of BMS-650032 (24).

Discovery and early clinical evaluation of BMS-605339, a potent and orally efficacious tripeptidic acylsulfonamide NS3 protease inhibitor for the treatment of hepatitis C virus infection.

The discovery of BMS-605339 (35), a tripeptidic inhibitor of the NS3/4A enzyme, is described. This compound incorporates a cyclopropylacylsulfonamide moiety that was designed to improve the potency of carboxylic acid prototypes through the introduction of favorable nonbonding interactions within the S1' site of the protease. The identification of 35 was enabled through the optimization and balance of critical properties including potency and pharmacokinetics (PK). This was achieved through modulation of the P2* subsite of the inhibitor which identified the isoquinoline ring system as a key template for improving PK properties with further optimization achieved through functionalization. A methoxy moiety at the C6 position of this isoquinoline ring system proved to be optimal with respect to potency and PK, thus providing the clinical compound 35 which demonstrated antiviral activity in HCV-infected patients.

Biaryl isoxazolinone antibacterial agents.

In an era of increasing resistance to classical antibacterial agents, the synthetic oxazolidinone series of antibiotics has attracted much interest. Zyvoxtrade mark was the first oxazolidinone to be approved for clinical use against infections caused by multi-drug resistant Gram-positive bacteria. In the course of studies directed toward the discovery of novel antibacterial agents, a new series of synthetic phenyl-isoxazolinone agents that displayed potent activity against Gram-positive bacterial strains was recently discovered at Bristol-Myers Squibb. Extensive investigation of various substitutions on the phenyl ring was then undertaken. We report here, the synthesis and antibacterial activity of a series of biaryl isoxazolinone compounds.

Developments in antiviral drug design, discovery and development in 2004.

This article summarizes key aspects of progress made during 2004 toward the design, discovery and development of antiviral agents for clinical use. Important developments in the identification, characterization and clinical utility of inhibitors of human immunodeficiency virus; the hepatitis viruses, hepatitis B, hepatitis C; the herpes family of viruses, herpes simplex viruses 1 and 2, varicella zoster virus, Epstein-Barr virus and human cytomegalovirus; the respiratory viruses, influenza, respiratory syncytial virus, human metapneumovirus, picornaviruses, measles and the severe acute respiratory syndrome coronavirus; human papilloma virus; rotavirus; Ebola virus and West Nile virus, are reviewed.

Discovery of isoxazolinone antibacterial agents. Nitrogen as a replacement for the stereogenic center found in oxazolidinone antibacterials.

A series of potential antimicrobial derivatives possessing bioisosteric replacements for the central oxazolidinone ring found in oxazolidinone antibacterials have been prepared. The design concept involved replacement of the requisite sp(3)-hybridized stereogenic center found at the 5-position of the oxazolidinone with a nitrogen atom. The synthesis and antibacterial activity of three such ring systems, the benzisoxazolinones, pyrroles, and isoxazolinones is described.