A first in man study to evaluate the safety, pharmacokinetics and pharmacodynamics of RP7214, a dihydroorotate dehydrogenase inhibitor in healthy subjects.

Dihydroorotate dehydrogenase (DHODH) is a mitochondrial enzyme that is essential for pyrimidine de novo synthesis. Rapidly growing cancer cells and replicating viruses are dependent on host cell nucleotides, the precursors of which are provided by DHODH. Hence, DHODH becomes an ideal target for pharmacological intervention. RP7214 is a potent and selective inhibitor of human DHODH and has shown antiviral and antileukaemic activity in preclinical studies. This paper describes the phase I study that evaluated the safety and pharmacokinetics of single and multiple ascending doses (SAD and MAD) and the food effect of RP7214 in healthy volunteers (HVs). The study was a randomized, double-blind, placebo-controlled trial of single dose (100, 200 and 400 mg QD), multiple doses (200 and 400 mg BID for 7 days) and a food effect study at a single dose of 200 mg. A total of 18, 12 and 12 HVs were enrolled in the SAD, MAD and food effect parts of the study, respectively. RP7214 was well tolerated at all dose levels. There were 20 treatment-emergent adverse events (TEAEs) reported, out of which most were mild to moderate in severity while three TEAEs were grade ≥3. RP7214 showed accumulation on multiple dosing. Steady-state concentrations were reached within about 3-6 days. The mean plasma half-life at steady-state was 12.8 hours (9.9-15.3). Food did not impact the absorption of RP7214. Inhibition of DHODH, as evidenced by increased dihydroorotate levels, was observed, confirming target engagement. The high systemic exposure with a favourable safety profile shows potential for the development of RP7214 in SARS-CoV-2 and acute myeloid leukaemia (NCT04680429).

A first-in-human study to evaluate the safety, tolerability and pharmacokinetics of RP3128, an oral calcium release-activated calcium (CRAC) channel modulator in healthy volunteers.

WHAT IS KNOWN AND OBJECTIVE: RP3128, a novel, orally available modulator of calcium released activated calcium (CRAC) channel, is being developed for the potential treatment of autoimmune and inflammatory diseases. RP3128 showed nano-molar potency and activity in a range of in vitro and in vivo models of inflammation. We report a first-in-human study investigating the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of RP3128 in healthy subjects. METHODS: A randomized, double-blind, placebo-controlled trial of single (25, 50, 100, 200 and 400 mg) and multiple (7 days: 25, 100 and 400 mg once daily) doses of RP3128 were performed. Thirty-two and 24 subjects were randomized in the single ascending dose (SAD) and multiple ascending dose (MAD) parts, respectively. RESULTS AND DISCUSSION: RP3128 was well tolerated, with no dose-limiting toxicity at single and multiple doses. Incidence of treatment emergent adverse events (TEAEs) did not increase with ascending RP3128 doses. No changes were seen in cognitive function and ECG parameters. RP3128 was rapidly absorbed. Elimination was slow with a half-life of more than 80 h. Exposures increased with increasing doses. Accumulation was seen on repeated dosing. PD response, as evidenced by lower plasma levels of tumour necrosis factor-alfa (TNFα) and interleukin-4 (IL-4), was seen when compared to pre-dose values or placebo. WHAT IS NEW AND CONCLUSION: The safety, tolerability and PK/PD profile of RP3128 demonstrates its potential to be developed in inflammatory disorders and support further clinical development (ClinicalTrials.gov number: NCT02958982).

Phase I/Ib Study of Tenalisib (RP6530), a Dual PI3K δ/γ Inhibitor in Patients with Relapsed/Refractory T-Cell Lymphoma.

Tenalisib (RP6530), a dual phosphoinositide 3-kinase δ/γ inhibitor was evaluated in a phase I/Ib study for maximum tolerated dose (MTD), pharmacokinetics, and efficacy in patients with relapsed/refractory peripheral and cutaneous T-Cell Lymphoma (TCL). Histologically confirmed (TCL) patients, with ≥1 prior therapy received Tenalisib orally in a 28-day cycle in doses of 200 to 800 mg twice daily (800 mg in fasting and fed state) in escalation phase (n = 19) and 800 mg twice daily (fasting) in expansion phase (n = 39). The most frequently reported treatment emergent adverse events (TEAE) and related TEAE were fatigue (45%) and transaminase elevations (33%), respectively. Most frequently reported related Grade ≥3 TEAE was transaminase elevation (21%). Two dose-limiting toxicities occurred in the 800 mg fed cohort; hence, 800 mg fasting dose was deemed MTD. Tenalisib was absorbed rapidly with a median half-life of 2.28 h. Overall response rate in 35 evaluable patients was 45.7% (3 complete response (CR); 13 partial response (PR)) and median duration of response was 4.9 months. Responding tumors showed a marked downregulation of CD30, IL-31 and IL-32α. With an acceptable safety and promising clinical activity, Tenalisib can be a potential therapeutic option for relapsed/refractory TCL. Currently, a phase I/II combination study with romidepsin is ongoing.

Calcium Release-Activated Calcium (CRAC) Channel Inhibition Suppresses Pancreatic Ductal Adenocarcinoma Cell Proliferation and Patient-Derived Tumor Growth.

Pancreatic ductal adenocarcinoma (PDAC) remains an unmet clinical problem in urgent need of newer molecularly driven treatment modalities. Calcium signals, particularly those associated with calcium release-activated calcium (CRAC) channels, are known to influence the development, growth, and metastasis of many cancers. This is the first study investigating the impact of CRAC channel inhibition on PDAC cell lines and patient-derived tumor models. PDAC cell lines were exposed to a novel CRAC channel inhibitor, RP4010, in the presence or absence of standard of care drugs such as gemcitabine and nab-paclitaxel. The in vivo efficacy of RP4010 was evaluated in a hyaluronan-positive PDAC patient-derived xenograft (PDx) in the presence or absence of chemotherapeutic agents. Treatment of PDAC cell lines with single-agent RP4010 decreased cell growth, while the combination with gemcitabine/nab-paclitaxel exhibited synergy at certain dose combinations. Molecular analysis showed that RP4010 modulated the levels of markers associated with CRAC channel signaling pathways. Further, the combination treatment was observed to accentuate the effect of RP4010 on molecular markers of CRAC signaling. Anti-tumor activity of RP4010 was enhanced in the presence of gemcitabine/nab-paclitaxel in a PDAC PDx model. Our study indicates that targeting CRAC channel could be a viable therapeutic option in PDAC that warrants further clinical evaluation.

A First-in-human Study of Tenalisib (RP6530), a Dual PI3K δ/γ Inhibitor, in Patients With Relapsed/Refractory Hematologic Malignancies: Results From the European Study.

BACKGROUND: Tenalisib (RP6530) is a novel, highly specific, dual phosphoinositide-3 kinases (PI3K) δ/γ inhibitor with nano-molar potency. MATERIAL AND METHODS: This was a phase I, open-label, 3 + 3 dose escalation, maximum tolerated dose determination study to evaluate the safety, pharmacokinetics, and efficacy of tenalisib in patients with relapsed/refractory hematologic malignancies. Tenalisib was administered orally twice/thrice daily in 28-day cycles with starting dose of 25 mg twice daily. RESULTS: Thirty-five patients were enrolled across 11 dose levels. No dose limiting toxicity was reported at any of the dose levels. The most common treatment-emergent adverse events irrespective of causality were asthenia and cough in 15 (43%) patients and pyrexia in 13 (37%) patients. The most frequently reported related treatment-emergent adverse events were diarrhea, nausea, and vomiting. Related grade 3/4 adverse events were limited to events of hypertriglyceridemia, neutropenia, and diarrhea. Pharmacokinetics showed rapid absorption. Based on maximum plasma concentration and area under the plasma-concentration time curve, dose proportionality was observed up to 400 mg dose. Of 31 patients included in the efficacy analysis, complete response was seen in 2 (7%) patients and partial response in 4 (13%) patients, with an overall response rate of 19% and a disease-control rate of 61%. The median duration of response was 5.7 months. Responders demonstrated a marked downregulation of phospho-AKT on C1D8. CONCLUSION: Tenalisib demonstrated acceptable safety up to 1200 mg twice a day with no dose-limiting toxicities. Consistent clinical response was seen at doses 200 mg BID and above. Pharmacodynamics correlated well with clinical outcome. Further phase I/II studies are being undertaken to evaluate efficacy across different histologies.

Targeting Cancer Cells and Tumor Microenvironment in Preclinical and Clinical Models of Hodgkin Lymphoma Using the Dual PI3Kδ/γ Inhibitor RP6530.

PURPOSE: Tumor-associated macrophages (TAMs) and the hyperactivation of the PI3K/AKT pathway are involved in the pathogenesis of Hodgkin lymphoma and affect disease outcome. Because the δ and γ isoforms of PI3K are overexpressed in Hodgkin/Reed-Sternberg (HRS) cells and the tumor microenvironment (TME), we propose that the PI3Kδ/γ inhibitor RP6530 might affect both HRS cells and TME, ultimately leading to an enhanced antitumor response. EXPERIMENTAL DESIGN: Hodgkin lymphoma cell lines (L-540, KM-H2, and L-428) and primary human macrophages were used to investigate the activity of RP6530 in vitro and in vivo in Hodgkin lymphoma cell line xenografts. RESULTS: In vitro, RP6530 besides killing and inhibiting the proliferation of Hodgkin lymphoma cells, downregulated lactic acid metabolism, switching the activation of macrophages from an immunosuppressive M2-like phenotype to a more inflammatory M1-like state. By RNA sequencing, we define tumor glycolysis as a specific PI3Kδ/γ-dependent pathway implicated in the metabolic reprogramming of cancer cells. We identify the metabolic regulator pyruvate kinase M2 as the main mediator of tumor-induced immunosuppressive phenotype of macrophages. Furthermore, we show in human tumor xenografts that RP6530 repolarizes TAMs into proinflammatory macrophages and inhibits tumor vasculature, leading to tumor regression. Interestingly, patients with Hodgkin lymphoma experiencing objective responses (complete response and partial response) in a phase I trial using RP6530 showed a significant inhibition of circulating myeloid-derived suppressor cells and an average mean reduction in serum thymus and activation-regulated chemokine levels of 40% (range, 4%-76%). CONCLUSIONS: Our results support PI3Kδ/γ inhibition as a novel therapeutic strategy that targets both malignant cells and the TME to treat patients with Hodgkin lymphoma.

Targeting Orai1-mediated store-operated calcium entry by RP4010 for anti-tumor activity in esophagus squamous cell carcinoma.

Esophageal cancer (EC) is the 6th leading cause of cancer mortality worldwide with poor prognosis, hence more effective chemotherapeutic drugs for this deadly disease are urgently needed. We previously reported that high expression of Orai1, a store-operated Ca2+entry (SOCE) channel, was associated with poor survival rate in EC patients and Orai1-mediated intracellular Ca2+ oscillations regulated cancer cell proliferation. Previous studies suggested that Orai1-mediated SOCE is a promising target for EC chemotherapy. Here, we evaluated the anti-cancer effect of a novel SOCE inhibitor, RP4010, in cultured EC cells and xenograft models. Compared to other previously reported SOCE channel inhibitors, RP4010 is more potent in blocking SOCE and inhibiting cell proliferation in EC and other cancer cells. Treatment with RP4010 resulted in reduction of intracellular Ca2+ oscillations, caused cell cycle arrest at G0/G1 phase in vitro, decreased nuclear translocation of nuclear factor kappa B (NF-κB) in vivo and in vitro, and inhibited tumor growth in vivo. Taken together, data demonstrated the therapeutic potential of RP4010 in EC patients via inhibition of SOCE-mediated intracellular Ca2+ signaling.

Phase I/II evaluation of RV1001, a novel PI3Kδ inhibitor, in spontaneous canine lymphoma.

BACKGROUND: RV1001 is a novel, potent, and selective PI3Kδ inhibitor. The purpose of this study was to evaluate the safety and efficacy of RV1001 in canine Non-Hodgkin lymphoma (NHL). METHODS AND RESULTS: Inhibition of endogenous pAKT by RV1001 in primary canine NHL cells was determined by Western blotting. A phase I study of RV1001 was performed in 21 dogs with naïve and drug resistant T and B-cell NHL to assess safety, pharmacokinetic profile, and response to therapy. The objective response rate was 62% (complete response (CR) n = 3; partial response (PR) n = 10), and responses were observed in both naïve and chemotherapy-resistant B and T cell NHL. This study provided the recommended starting dose for a phase II, non-pivotal, exploratory, open label multi-centered clinical trial in 35 dogs with naïve and drug resistant T and B-cell NHL, to further define the efficacy and safety profile of RV1001. The objective response rate in the phase II study was 77% (CR n = 1; PR n = 26). Clinical toxicities were primarily hepatobiliary and gastrointestinal, and were responsive to dose modifications and/or temporary drug discontinuation. Hepatotoxicity was the primary dose limiting toxicity. CONCLUSIONS: RV1001 exhibits good oral bioavailability, an acceptable safety profile, and biologic activity with associated inhibition of pAKT in dogs with B and T cell NHL. Data from these studies can be leveraged to help inform the design of future studies involving isoform-selective PI3K inhibitors in humans.

Repurposing of a drug scaffold: Identification of novel sila analogues of rimonabant as potent antitubercular agents.

The structural similarity between an MmpL3 inhibitor BM212, and a cannabinoid receptor modulator rimonabant, prompted us to investigate the anti-tubercular activity of rimonabant and its analogues. Further optimization, particularly through incorporation of silicon into the scaffold, resulted in new compounds with significant improvement in anti-tubercular activity against Mycobacterium tuberculosis (H37Rv). The sila analogue 18a was found to be the most potent antimycobacterial compound (MIC, 31 ng/mL) from this series with an excellent selectivity index.

Simultaneous Quantification of Baricitinib and Methotrexate in Rat Plasma by LC-MS/MS: Application to a Pharmacokinetic Study.

Efficacy assessments using a combination of baricitinib and methotrexate necessitate the development of an analytical method for the determination of both drugs in plasma with precision. A high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of baricitinib and methotrexate in rat plasma. Extraction of baricitinib, methotrexate, and tolbutamide (internal standard; IS) from 50 µL of rat plasma was carried out by protein precipitation with methanol. Chromatographic separation of the analytes was performed on the YMC pack ODS AM (150 mm × 4.6 mm, 5 µm) column under gradient conditions with methanol: 2.0 mM ammonium acetate buffer as the mobile phases at a flow rate of 1 mL/min. The precursor ion and product ion transition for both analytes and IS were monitored on a triple quadrupole mass spectrometer, operated with selective reaction monitoring in positive ionization mode. The method was validated over a concentration range of 0.5-250.00 ng/mL for baricitinib and methotrexate. Mean extraction recoveries for baricitinib, methotrexate, and IS of 86.8%, 89.4%, and 91.8% were consistent across low, medium, and high QC levels, respectively. Precision and accuracy at low, medium, and high quality control levels were less than 15% across the analytes. Benchtop, wet, freeze-thaw, and long-term stability were evaluated for both of the analytes. The analytical method was applied to support the pharmacokinetic study of simultaneous estimation of baricitinib and methotrexate in Wistar rats. Assay reproducibility was demonstrated by reanalysis of 18 incurred samples.

Pharmacodynamic evaluation of RP3128, a novel and potent CRAC channel inhibitor in guinea pig models of allergic asthma.

The increase in intracellular Ca(2+) levels through the activation of Ca(2+) release-activated Ca(2+) (CRAC) channels is essential for mediating a wide scale of immune cell responses. Emerging evidence indicates an involvement of abnormal CRAC channel activity in human diseases such as certain types of immunodeficiency, autoimmunity and allergic disorders. This objective of this study was to evaluate the therapeutic potency of a novel CRAC channel inhibitor, RP3128, in experimental models of allergic asthma using guinea pigs. Ovalbumin-induced allergic airway inflammation was determined upon acute and long-term (14 days) oral administration of RP3128. In vivo changes in specific airways resistance (sRaw) and amplitude of isometric contraction (mN) of ASM (in vitro) were estimated to evaluate bronchodilatory effect upon acute and long-term administration of RP3128 or salbutamol. Exhaled nitric oxide (eNO), immunohistochemical and histological analysis of cellular infiltration in airways tissue, and levels of cytokines in plasma as well as bronchoalveolar lavage fluid (BALF), were determined using Bio-Plex® 200 System (BIO-RAD, USA). Ciliary beat frequency (CBF, in Hz) was estimated using a high-speed video camera and LabVIEW™ Software. Additionally, the impact of RP3128 and budesonide on mucociliary clearance was determined. Acute and long-term administration of RP3128 resulted in significant bronchodilation. Long-term administration of RP3128 exceeded the bronchodilatory effect of salbutamol and significantly decreased eNO and cytokine levels in plasma and BALF, which together with histological and immunohistochemical analysis validated its anti-inflammatory effect compared to budesonide. Data demonstrate the therapeutic potential of RP3128 in respiratory diseases causally associated with allergic inflammation.

Cathepsin D inhibitors as potential therapeutics for breast cancer treatment: Molecular docking and bioevaluation against triple-negative and triple-positive breast cancers.

The main aim of this study was to discover small molecule inhibitors against Cathepsin D (CatD) (EC.3.4.23.5), a clinically proven prognostic marker for breast cancer, and to explore the mechanisms by which CatD could be a useful therapeutic target for triple-positive and triple-negative breast cancers (TPBC & TNBC). The crystal structure of CatD at 2.5 Å resolution (PDB: 1LYB), which was complexed with Pepstatin A, was selected for computer-aided molecular modeling. The methods used in our study were pharmacophore modeling and molecular docking. Virtual screening was performed to identify small molecules from an in-house database and a large commercial chemical library. Cytotoxicity studies were performed on human normal cell line HEK293T and growth inhibition studies on breast adenocarcinoma cell lines, namely MCF-7, MDA-MB-231, SK-BR-3, and MDA-MB-468. Furthermore, RT-PCR analysis, in vitro enzyme assay, and cell cycle analysis ascertained the validity of the selected molecules. A set of 28 molecules was subjected to an in vitro fluorescence-based inhibitory activity assay, and among them six molecules exhibited >50 % inhibition at 25µM. These molecules also exhibited good growth inhibition against TPBC and TNBC cancer types. Among them, molecules 1 and 17 showed single-digit micromolar GI50 values against MCF-7 and MDA-MB-231 cell lines.

Energy-Based Pharmacophore and Three-Dimensional Quantitative Structure--Activity Relationship (3D-QSAR) Modeling Combined with Virtual Screening To Identify Novel Small-Molecule Inhibitors of Silent Mating-Type Information Regulation 2 Homologue 1 (SIRT1).

Silent mating-type information regulation 2 homologue 1 (SIRT1), being the homologous enzyme of silent information regulator-2 gene in yeast, has multifaceted functions. It deacetylates a wide range of histone and nonhistone proteins; hence, it has good therapeutic importance. SIRT1 was believed to be overexpressed in many cancers (prostate, colon) and inflammatory disorders (rheumatoid arthritis). Hence, designing inhibitors against SIRT1 could be considered valuable. Both structure-based and ligand-based drug design strategies were employed to design novel inhibitors utilizing high-throughput virtual screening of chemical databases. An energy-based pharmacophore was generated using the crystal structure of SIRT1 bound with a small molecule inhibitor and compared with a ligand-based pharmacophore model that showed four similar features. A three-dimensional quantitative structure-activity relationship (3D-QSAR) model was developed and validated to be employed in the virtual screening protocol. Among the designed compounds, Lead 17 emerged as a promising SIRT1 inhibitor with IC50 of 4.34 µM and, at nanomolar concentration (360 nM), attenuated the proliferation of prostate cancer cells (LnCAP). In addition, Lead 17 significantly reduced production of reactive oxygen species, thereby reducing pro inflammatory cytokines such as IL6 and TNF-α. Furthermore, the anti-inflammatory potential of the compound was ascertained using an animal paw inflammation model induced by carrageenan. Thus, the identified SIRT1 inhibitors could be considered as potent leads to treat both cancer and inflammation.

Design, Synthesis, and Identification of Silicon Incorporated Oxazolidinone Antibiotics with Improved Brain Exposure.

Therapeutic options for brain infections caused by pathogens with a reduced sensitivity to drugs are limited. Recent reports on the potential use of linezolid in treating brain infections prompted us to design novel compounds around this scaffold. Herein, we describe the design and synthesis of various oxazolidinone antibiotics with the incorporation of silicon. Our findings in preclinical species suggest that silicon incorporation is highly useful in improving brain exposures. Interestingly, three compounds from this series demonstrated up to a 30-fold higher brain/plasma ratio when compared to linezolid thereby indicating their therapeutic potential in brain associated disorders.

Targeting NAMPT for Therapeutic Intervention in Cancer and Inflammation: Structure-Based Drug Design and Biological Screening.

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate limiting enzyme that plays an important role in the synthesis of nicotinamide adenine dinucleotide (NAD) via a salvage pathway. Along with a role in bioenergetics, NAMPT regulates the activity of proteins such as SIRT-1 that utilize NAD as a cofactor. As NAD metabolism is usually high in diseased conditions, it has been hypothesized and proven that NAMPT is over expressed in various cancers and inflammatory disorders. Inhibitors targeting NAMPT could therefore be useful in treating disorders arising from aberrant NAMPT signalling. In this study, inhibitors against NAMPT were designed using an energy-based pharmacophore strategy and evaluated for efficacy in cellular assays. Besides reducing cellular pools of NAD and NMN, NAMPT inhibitors decreased concentrations of reactive oxygen species as well as mRNA levels of TNFα and IL6, thereby implicating their potential in alleviating the inflammatory process. In addition, reduced NAD levels corroborated with an induction of apoptosis in prostate cancer cell lines.

A Novel, Potent, Small Molecule AKT Inhibitor Exhibits Efficacy against Lung Cancer Cells In Vitro.

PURPOSE: Anomalies of Akt regulation, including overexpression in lung cancer, impart resistance to conventional chemotherapy and radiation, thereby implicating this kinase as a therapeutic intervention point. A novel scaffold of Akt inhibitors was developed through virtual screening of chemical databases available at Birla Institute of Technology and Science, Pilani, Hyderabad, based on docking studies using Maestro. A benzothienopyrimidine derivative (BIA-6) was identified as a potential lead molecule that inhibited Akt1 enzyme activity with an IC50 of 256 nM. MATERIALS AND METHODS: BIA-6 was tested for in vitro Akt1 inhibition using a fluorescence resonance energy transfer kit. Anti-proliferative activity was tested in NCI-H460, A549, NCI-H1975, and NCI-H2170 cell lines. The effect of the compound on p-Akt (S(473)) was estimated. RESULTS: BIA-6 allosterically caused a dose dependent reduction of growth of cell lines with a half maximal growth inhibition (GI50) range of 0.49 µM to 6.6 µM. Cell cycle analysis indicated that BIA-6 caused a G1 phase arrest at < 100 nM but led to apoptosis at higher doses. BIA-6 also exhibited synergism with standard chemotherapeutic agents. CONCLUSION: BIA-6 is a novel, allosteric Akt inhibitor with potent anti-cancer activity in lung cancer cell lines, that effectively blocks the phosphoinositide-3 kinase/Akt pathway with a high margin selectivity towards normal cells.

Simultaneous quantification of lenalidomide, ibrutinib and its active metabolite PCI-45227 in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

Efficacy assessments using a combination of ibrutinib and lenalidomide necessitate the development of an analytical method for determination of both drugs in plasma with precision. A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of lenalidomide, ibrutinib, and its active metabolite PCI45227 in rat plasma. Extraction of lenalidomide, ibrutinib, PCI45227 and tolbutamide (internal standard; IS) from 50 µl rat plasma was carried out by liquid-liquid extraction with ethyl acetate:dichloromethane (90:10) ratio. Chromatographic separation of analytes was performed on YMC pack ODS AM (150 mm × 4.6 mm, 5 µm) column under gradient conditions with acetonitrile:0.1% formic acid buffer as the mobile phases at a flow rate of 1 ml/min. Precursor ion and product ion transition for analytes and IS were monitored on a triple quadrupole mass spectrometer, operated in the selective reaction monitoring with positive ionization mode. Method was validated over a concentration range of 0.72-183.20 ng/ml for ibrutinib, 0.76-194.33 ng/ml for PCI-45227 and 1.87-479.16 ng/ml for lenalidomide. Mean extraction recovery for ibrutinib, PCI-45227, lenalidomide and IS of 75.2%, 84.5%, 97.3% and 92.3% were consistent across low, medium, and high QC levels. Precision and accuracy at low, medium and high quality control levels were less than 15% across analytes. Bench top, wet, freeze-thaw and long term stability was evaluated for all the analytes. The analytical method was applied to support a pharmacokinetic study of simultaneous estimation of lenalidomide, ibrutinib, and its active metabolite PCI-45227 in Wistar rat. Assay reproducibility was demonstrated by re-analysis of 18 incurred samples.

Structure-based drug design of small molecule SIRT1 modulators to treat cancer and metabolic disorders.

Sirtuins comprise a family of deacetylase enzymes that catalyze the removal of an acetyl moiety from the ɛ-amino group of lysine residues within protein targets. Sirtuin 1(SIRT1), a NAD(+) dependent class III histone deacetylase is involved in a variety of human disorders such as obesity, type II diabetes, cancer and aging. Inhibition of SIRT1 could be useful for cancer treatment while activators can be useful for longevity and treating metabolic disorders. Hence we undertook an effort to design both inhibitors and activators using structure-based drug design techniques and report here the biological proof of concept. In this paper, we report diverse small molecule inhibitors with a potential to attenuate cancer growth designed based on high-throughput virtual screening and docking using the crystal structure of SIRT1. And small molecule activators with potential to suppress adipogenesis differentiation indicating their usefulness in obesity control was designed based on a homology model of SIRT1 activator domain.

DDD-028: a potent potential non-opioid, non-cannabinoid analgesic for neuropathic and inflammatory pain.

DDD-028 (4), a novel pentacyclic pyridoindolobenzazepine derivative was evaluated in vitro for receptor binding affinity and in vivo for analgesic activity using rodent models of neuropathic and inflammatory pain. DDD-028 does not bind to opioid, cannabinoid, dopamine, or histamine receptors. DDD-028 is very active even at the low oral dose of 1-5 mg/kg in both neuropathic, (spinal nerve ligation and chronic constriction injury) and inflammatory (Complete Freund's Adjuvant Induced) models of pain. DDD-028 appears to be about 6-fold more potent than pregabalin and indomethacin. Visual observation of all the animals used in these studies indicated that DDD-028 is well tolerated without any sedation. Thus, DDD-028 seems to be a promising candidate for the treatment of neuropathic and inflammatory pain without the possible side effects or abuse potential associated with opioid or cannabinoid activities.

Simultaneous quantification of ruxolitinib and nilotinib in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

Efficacy assessments using a combination of ruxolitinib and nilotinib necessitate the development of a high precision analytical method for determination of both drugs in plasma. A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of ruxolitinib and nilotinib in rat plasma. Extraction of ruxolitinib, nilotinib and dasatinib (internal standard; IS) from 50µl rat plasma was carried out by protein precipitation with methanol. Chromatographic separation of analytes was performed on YMC pack ODS AM (150mm×4.6mm, 5µm) column under gradient conditions with acetonitrile:2.0mM ammonium acetate buffer as the mobile phase at a flow rate of 1ml/min. Precursor ion and product ion transition for both analytes and IS were monitored on a triple quadrupole mass spectrometer, operated in the selective reaction monitoring with positive ionization mode. Method was validated over a concentration range of 0.16-247ng/ml for ruxolitinib and 0.86-219ng/ml for nilotinib. Mean extraction recovery for ruxolitinib, nilotinib, and IS of 99.6%, 97.6% and 90.3% were consistent across low, medium, and high QC levels. Precision and accuracy at low, medium and high quality control levels were less than 15% across analytes. Bench top, wet, freeze-thaw and long term stability were evaluated for both analytes. The analytical method was applied to support a pharmacokinetic study of simultaneous estimation of ruxolitinib and nilotinib in Wistar rat. Assay reproducibility was demonstrated by re-analysis of 18 incurred samples.