Drug discovery and development in idiopathic pulmonary fibrosis: challenges and opportunities.

The pharmacological and adverse effect profiles of the two approved therapies for IPF make the development of new therapies challenging. Considering the similarity of the characteristics of drug candidates to Standard of Care is important in defining positioning and development strategies for this disease.

The future R&D landscape in non-alcoholic steatohepatitis (NASH).

Nonalcoholic steatohepatitis (NASH) is emerging as a major public health issue for the 21st century and is associated with significant liver-related morbidity and mortality. At present, there are no approved drug therapies for NASH. Consequently, NASH has become the focus of significant public and private research and development. In this review, we highlight the research and development (R&D) challenges and opportunities in this emerging therapeutic area. In particular, we consider the impact of the development of new biomarker strategies on clinical trial execution and design, and the positioning of single and combination therapies in future approaches to the treatment of NASH.

Therapeutic dosing of an orally active, selective cathepsin S inhibitor suppresses disease in models of autoimmunity.

The purpose of the study was to examine the potential of inhibition of cathepsin S as a treatment for autoimmune diseases. A highly selective cathepsin S inhibitor, CSI-75, was shown to upregulate levels of the cathepsin S substrate, invariant chain Lip10, in vitro as well as in vivo in C57Bl/6 mice after oral administration. Functional activity of the compound was shown by a reduction in the OVA-specific response of OVA-sensitized splenocytes from C57Bl/6 mice as well as from OVA-TCR transgenic mice (DO11.10). Since these studies revealed a selective suppression of the Th1 and Th17 cytokines causing a shift to Th2, CSI-75 was tested in the murine HC-gp39-immunization model. Indeed, CSI-75 specifically reduced the circulating HC-gp39-specific IgG2a in these mice indicating selective inhibition of the Th1 type of response in vivo. The importance of especially the Th1 and Th17 cell subsets in the pathology of autoimmune diseases, renders CatS inhibition a highly interesting potential therapeutic treatment of autoimmune diseases. Therefore, CSI-75 was tested in a murine model of multiple sclerosis (i.e. experimental autoimmune encephalomyelitis (EAE)) in a semi-therapeutic setting (ie. oral treatment after initial sensitization to antigen). Finally, in a murine model with features resembling rheumatoid arthritis (the collagen-induced arthritis (CIA) model), CSI-75 was tested in a therapeutic manner (after disease development). CSI-75 caused a significant reduction in disease score in both disease models, indicating a promising role for CatS inhibitors in the area of therapeutic treatments for autoimmune diseases.

Optimisation of 6-substituted isoquinolin-1-amine based ROCK-I inhibitors.

Rho kinase is an important target implicated in a variety of cardiovascular diseases. Herein, we report the optimisation of the fragment derived ATP-competitive ROCK inhibitors 1 and 2 into lead compound 14A. The initial goal of improving ROCK-I potency relative to 1, whilst maintaining a good PK profile, was achieved through removal of the aminoisoquinoline basic centre. Lead 14A was equipotent against both ROCK-I and ROCK-II, showed good in vivo efficacy in the spontaneous hypertensive rat model, and was further optimised to demonstrate the scope for improving selectivity over PKA versus hydroxy Fasudil 3.

Fragment-based discovery of 6-substituted isoquinolin-1-amine based ROCK-I inhibitors.

Fragment-based NMR screening of a small literature focused library led to identification of a historical thrombin/FactorXa building block, 17A, that was found to be a ROCK-I inhibitor. In the absence of an X-ray structure, fragment growth afforded 6-substituted isoquinolin-1-amine derivatives which were profiled in the primary ROCK-I IMAP assay. Compounds 23A and 23E were selected as fragment optimized hits for further profiling. Compound 23A has similar ROCK-1 affinity, potency and cell based efficacy to the first generation ROCK inhibitors, however, it has a superior PK profile in C57 mouse. Compound 23E demonstrates the feasibility of improving ROCK-1 affinity, potency and cell based efficacy for the series, however, it has a poor PK profile relative to 23A.

6-Phenyl-1H-imidazo[4,5-c]pyridine-4-carbonitrile as cathepsin S inhibitors.

6-Phenyl-1H-imidazo[4,5-c]pyridine-4-carbonitrile analogues were identified as potent and selective cathepsin S inhibitor against both purified enzyme and in human JY cell based cellular assays. This core has a very stable thio-trapping nitrile war-head in comparison with the well reported pyrimidine-2-carbonitrile cysteine cathepsin inhibitors. Compound 47 is also very potent in in vivo mouse spleenic Lip10 accumulation assays.

Triazine and pyrimidine based ROCK inhibitors with efficacy in spontaneous hypertensive rat model.

The profile of a series of triazine and pyrimidine based ROCK inhibitors is described. An initial binding mode was established based on a homology model and the proposed interactions are consistent with the observed SAR. Compounds from the series are potent in a cell migration assay and possess a favorable kinase selectivity. In vivo activity was demonstrated for compound 1A in a spontaneous hypertensive rat model.

Noninvasive diagnosis of ruptured peripheral atherosclerotic lesions and myocardial infarction by antibody profiling.

Novel biomarkers, such as circulating (auto)antibody signatures, may improve early detection and treatment of ruptured atherosclerotic lesions and accompanying cardiovascular events, such as myocardial infarction. Using a phage-display library derived from cDNAs preferentially expressed in ruptured peripheral human atherosclerotic plaques, we performed serological antigen selection to isolate displayed cDNA products specifically interacting with antibodies in sera from patients with proven ruptured peripheral atherosclerotic lesions. Two cDNA products were subsequently evaluated on a validation series of patients with peripheral atherosclerotic lesions, healthy controls, and patients with coronary artery disease at different stages. Our biomarker set was able to discriminate between patients with peripheral ruptured lesions and patients with peripheral stable plaques with 100% specificity and 76% sensitivity. Furthermore, 93% of patients with an acute myocardial infarction (AMI) tested positive for our biomarkers, whereas all patients with stable angina pectoris tested negative. Moreover, 90% of AMI patients who initially tested negative for troponin T, for which a positive result is known to indicate myocardial infarction, tested positive for our biomarkers upon hospital admission. In conclusion, antibody profiling constitutes a promising approach for noninvasive diagnosis of atherosclerotic lesions, because a positive serum response against a set of 2 cDNA products showed a strong association with the presence of ruptured peripheral atherosclerotic lesions and myocardial infarction.

Oestrogen-mediated cardioprotection following ischaemia and reperfusion is mimicked by an oestrogen receptor (ER)alpha agonist and unaffected by an ER beta antagonist.

Oestrogen protects the heart from ischaemic injury. The current study aims to characterise two novel oestrogen receptor (ER) ligands, an ER alpha agonist ERA-45 and an ER beta antagonist ERB-88, and then use them to investigate the roles of ER alpha and ER beta in mediating the cardioprotection by E from ischaemia-reperfusion injury in the rat. The ER ligands were characterised by gene transactivation assay using ER-transfected Chinese hamster ovary (CHO) cells and in bioavailability studies in vivo. Female rats (n=48) were ovariectomised and implanted with 17beta-oestradiol (17 beta E(2)) releasing or placebo pellets. ERA-45, ERB-88 or vehicle was administered for 5 days prior to ischaemia-reperfusion studies. Necrosis, neutrophil infiltration (myeloperoxidase activity) and oxidant stress production (electron paramagnetic resonance) from the area-at-risk were measured to assess reperfusion injury. The ER alpha agonist ERA-45 showed more than 35-fold selectivity for ER alpha compared with ER beta gene transactivation. In vitro, the ER beta antagonist ERB-88 inhibited transactivation by 17 beta E(2) via ER beta with 46-fold selectivity relative to inhibition via ER alpha. In vivo, 17 beta E(2) significantly reduced neutrophil infiltration, oxidant stress and necrosis following ischaemia and reperfusion. Cardioprotection by 17 beta E(2) was not inhibited by ERB-88 but was completely reproduced by ERA-45. In conclusion, protection of the rat heart after ischaemia-reperfusion by 17 beta E(2) is achieved through the reduction of cardiomyocyte death, neutrophil infiltration and oxygen-free radical availability.The results of this study indicate that these effects are primarily mediated via activation of ER alpha.