DiscoveryDiagram

Aurigene’s discovery research model. This is the core strength that has enabled Aurigene to build an exemplary track-record for managing and delivering successful candidates to its partners.

Drug discovery solutions at Aurigene are provided not just as integrated research services but also in the form of standalone research services, if desired. Standalone services are offered in synthetic chemistry (Small molecules and peptides), scale up, molecular modeling, protein production and structural biology, invitro DMPK, invivo pharmacology, invitro and invivo toxicology and pharmaceutical development.

Genetic Validation

target-validation1

  • Transfection of siRNA for the target of interest (T= targeting) resulted in reduction in target protein levels as determined by Western blot analysis (Panel A) that correlated well with inhibition of substrate modulation in a biochemical assay (Panel B) and inhibition of NSCLC cell proliferation (Panel C).

Pharmacological Validation

target-validation2

  • Studies with a selective small molecule inhibitor indicated significant reduction of proliferation of cancer cells but not normal cells (Panel A).
  • Sensitivity of breast cancer cells correlated with the expression of a helper protein, which could potentially be used a predictive biomarker (Panel B).

Early Efficacy and Toxicity Evaluation

  • Comparison of the doses required to achieve efficient tumor growth inhibition (TGI) and that shows good tolerability in repeated dose studies indicated an acceptable therapeutic window.

Validation summary

  • Based on the findings in target validation studies, this target was selected for a fully resourced drug discovery program.
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  • Based on literature crystal structure of matriptase catalytic domain in complex with benzamidine sulfate, we hypothesized that benzamidine could engage sulfate pocket & spacious solvent exposed S3/S4 region.
  • Few focused libraries were designed and screened.
  • The initial hits were further refined through series of co-crystal structure and modeling analysis (SBDD) to get potent hit (Ki = 40nM).
  • The hit had favorable selectivity over undesirable serine proteases, besides desired cellular activity, solubility, and metabolic stability.

Ref: ACS Med. Chem. Lett. 2013, 4, 1152−1157

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  • Compound-1 was a potent ALK inhibitor (WT and mutant), with undesired inhibition of Aurora A kinase activity (implicated in cardio toxicity).
  • From SBDD analysis, it was found proximity of pyrazole N2 nitrogen to catalytic Lys-162 of Aurora A (3Å distance) compared to ALK (4.4Å distance), was responsible for lack of selectivity.
  • Disrupting the above interaction by having dimethyl pyrazole in compound-2, resulted in greater selectivity for Aurora A.

Ref: Bioorg. Med. Chem. Lett., 2013, 23, 4911

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  • The high efflux ratio of compound-1 was reduced by
    • H-bond donor capacity reduced by changing from primary amide (1) to secondary amide (2)
    • Decreasing H-bond acceptor potential (oxetane replaced with azetidine)
  • The attenuation of efflux in compound-2 resulted in improved gastrointestinal absorption and bioavailability (> 30%).