Post-marketing study of clinical experience of atorvastatin 80 mg vs 40 mg in Indian patients with acute coronary syndrome- a randomized, multi-centre study (CURE-ACS).

OBJECTIVE: To generate comparative clinical data in Indian patients with acute coronary syndrome (ACS) in terms of safety and efficacy of atorvastatin 80 mg vis-à-vis atorvastatin 40 mg MATERIALS AND METHODS: A total of 236 patients with diagnosed ACS (with TIMI Risk score > or = 3) within preceding 10 days were randomized to receive either atorvastatin 80 mg or atorvastatin 40 mg once daily for 12 weeks. Out of 236 patients, data for 173 was analyzed who had both baseline and post-baseline lipid assessment. The primary end point of the trial was percentage change in LDL-C at the end of treatment from baseline. Other end points were change in high sensitivity C reactive protein, incidence of increase in liver enzymes > or = 3 times upper limit of normal and incidence of myotoxicity (with or without elevation of creatinine phosphokinase) at the end of treatment. RESULTS: A dose-dependent response was observed with greater reduction of LDL -C in atorvastatin 80 mg (27.5% vs 19.04%) than that of atorvastatin 40 mg group. Both the treatment groups had a significant reduction (p < 0.001) in LDL-C at the end of 6 and 12 weeks in comparison to baseline. hs-CRP was also significantly reduced (p < 0.001) in both the treatment groups i.e. atorvastatin 80 mg (76.15%) and atorvastatin 40 mg (84.4%) from baseline at the end of 12 weeks. Both doses of atorvastatin were well tolerated. No patient had elevation of (> or = 3 times of upper limit of normal) liver enzymes or creatinine phosphokinase. One patient on atorvastatin 80 mg complained of myalgia. There were no dose-related differences in incidence of adverse events between two treatment groups. CONCLUSION: The CURE-ACS trial indicated that atorvastatin 80 mg was more effective than atorvastatin 40 mg in terms of reduction in LDL cholesterol and was as safe and well tolerated as 40 mg dose in Indian patients with ACS.

High-throughput screening of RNA polymerase inhibitors using a fluorescent UTP analog.

RNA polymerase (RNAP) is a well-validated target for the development of antibacterial and antituberculosis agents. Because the purification of large quantities of native RNA polymerase from pathogenic mycobacteria is hazardous and cumbersome, the primary screening was carried out using Escherichia coli RNAP. The authors have developed a high-throughput screening (HTS) assay to screen for novel inhibitors of RNAP. In this assay, a fluorescent analog of UTP, gamma-amino naphthalene sulfonic acid (gamma-AmNS) UTP, was used as one of the nucleotide substrates. Incorporation of UMP in RNA results in the release of gamma-AmNS-PPi, which has higher intrinsic fluorescence than (gamma-AmNS) UTP. The assay was optimized in a 384-well format and used to screen 670,000 compounds at a concentration of 10 microM. About 0.1% of the compounds showed more than 60% inhibition in the primary HTS. All the primary actives tested for dose response using the same assay had an EC(50) below 100 microM. Eighty percent of the primary HTS actives obtained using E. coli RNAP showed comparable activity against Mycobacterium smegmatis RNAP in the conventional radioactive assay. Activity of hits selected for the hit-to-lead optimization was also confirmed against Mycobacterium bovis RNAP which has >99% sequence identity with Mycobacterium tuberculosis RNAP subunits.

Assays, surrogates, and alternative technologies for a TB lead identification program targeting DNA gyrase ATPase.

Mycobacterium tuberculosis (Mtb) DNA gyrase ATPase was the target of a tuberculosis drug discovery program. The low specific activity of the Mtb ATPase prompted the use of Mycobacterium smegmatis (Msm) enzyme as a surrogate for lead generation, since it had 20-fold higher activity. Addition of GyrA or DNA did not significantly increase the activity of the Msm GyrB ATPase, and an assay was developed using GyrB alone. Inhibition of the Msm ATPase correlated well with inhibition of Mtb DNA gyrase supercoiling across three chemical scaffolds, justifying its use. As the IC50 of compounds approached the enzyme concentration, surrogate assays were used to estimate potencies (e.g., the shift in thermal melt of Mtb GyrB, which correlated well with IC(50)s >10 nM). Analysis using the Morrison equation enabled determination of K(i)(app)s in the sub-nanomolar range. Surface plasmon resonance was used to confirm these IC(50)s and measure the K ds of binding, but a fragment of Mtb GyrB had to be used. Across three scaffolds, the dissociation half life, t1/2, of the inhibitor-target complex was ≤ 8 min. This toolkit of assays was developed to track the potency of enzyme inhibition and guide the chemistry for progression of compounds in a lead identification program.

Therapeutic efficacy of a novel nanosomal docetaxel lipid suspension compared with taxotere in locally advanced or metastatic breast cancer patients.

BACKGROUND: Nanosomal docetaxel lipid suspension formulation was developed to eliminate ethanol and polysorbate 80 from the currently used docetaxel (Taxotere) drug for treatment of cancer patients. NDLS clinical safety and efficacy was evaluated and compared with Taxotere at 75 mg/m(2) in metastatic breast cancer patients. PATIENTS AND METHODS: A total of 72 patients were randomized in a ratio of 2:1 (NDLS:Taxotere). Patients treated with NDLS were not premedicated with corticosteroids as required with solvent-based Taxotere. Disease status and tumor response was assessed after every 2 cycles of treatment using Response Evaluation Criteria in Solid Tumors 1.1 guidelines through cycle 6. RESULTS: Overall therapeutic response (complete + partial) rate in metastatic breast cancer patients treated with NDLS and Taxotere were 35.5% and 26.3%, respectively, indicating better response in patients treated with NDLS. Patients in the NDLS group were not premedicated but the safety results of NDLS were found to be comparable with Taxotere. CONCLUSION: NDLS formulation with no premedication provides an alternative treatment option for breast cancer patients.

Assay development for identifying inhibitors of the mycobacterial FadD32 activity.

FadD32, a fatty acyl-AMP ligase (FAAL32) involved in the biosynthesis of mycolic acids, major and specific lipid components of the mycobacterial cell envelope, is essential for the survival of Mycobacterium tuberculosis, the causative agent of tuberculosis. The protein catalyzes the conversion of fatty acid to acyl-adenylate (acyl-AMP) in the presence of adenosine triphosphate and is conserved in all the mycobacterial species sequenced so far, thus representing a promising target for the development of novel antituberculous drugs. Here, we describe the optimization of the protein purification procedure and the development of a high-throughput screening assay for FadD32 activity. This spectrophotometric assay measuring the release of inorganic phosphate was optimized using the Mycobacterium smegmatis FadD32 as a surrogate enzyme. We describe the use of T m (melting temperature) shift assay, which measures the modulation of FadD32 thermal stability, as a tool for the identification of potential ligands and for validation of compounds as inhibitors. Screening of a selected library of compounds led to the identification of five novel classes of inhibitors.