A single ascending dose study of single-stranded oligodeoxyribonucleotide RO7062931 in Chinese healthy volunteers.

RO7062931 is an N-acetylgalactosamine (GalNAc)-conjugated single-stranded oligodeoxyribonucleotide complementary to hepatitis B virus RNA. GalNAc conjugation targets the liver through the asialoglycoprotein receptor (ASGPR). This phase I single ascending dose (SAD) study evaluated the safety, tolerability, and pharmacokinetics of RO7062931 in Chinese healthy volunteers. There were four SAD cohorts (0.3, 1.0, 2.0, and 4.0 mg/kg), in each of which healthy volunteers were randomized to a single subcutaneous (s.c.) injection of RO7062931 or matching placebo in a 4:1 ratio. Placebo recipients were pooled as one treatment group for safety assessments. A total of 41 healthy Chinese men received one dose of RO7062931 (n = 33) or placebo (n = 8) and completed the study (85-day follow-up). Adverse events (AEs) were reported in 22 of 33 (66.6%) RO7062931 recipients (n = 80 treatment-related) and seven of eight (87.5%) placebo recipients (n = 1 treatment-related). Apart from two moderate-intensity AEs, all AEs were mild. The most frequently reported AEs were influenza, injection-related reactions, and headache. Dose-proportional increases in plasma RO7062931 exposure were observed between the 0.3 and 1.0 mg/kg doses, whereas a supra-dose-proportional increase occurred at doses greater than or equal to 2.0 mg/kg, along with a marked increase in urinary excretion. Single s.c. dose of RO7062931 up to 4.0 mg/kg were safe and well-tolerated in healthy Chinese volunteers. Pharmacokinetic data suggested that ASGPR saturation had commenced between doses of 2.0 and 4.0 mg/kg. Results were broadly consistent with observations in primarily White subjects in the global first-in-human study of RO7062931.

Clinical Study of Single-Stranded Oligonucleotide RO7062931 in Healthy Volunteers and Patients With Chronic Hepatitis B.

BACKGROUND AND AIMS: RO7062931 is an N-acetylgalactosamine (GalNAc)-conjugated single-stranded locked nucleic acid oligonucleotide complementary to HBV RNA. GalNAc conjugation targets the liver through the asialoglycoprotein receptor (ASGPR). This two-part phase 1 study evaluated the safety, pharmacokinetics, and pharmacodynamics of RO7062931 in healthy volunteers and patients with chronic hepatitis B (CHB) who were virologically suppressed. APPROACH AND RESULTS: Part 1 was a single ascending dose study in healthy volunteers randomized to receive a single RO7062931 dose (0.1-4.0 mg/kg), or placebo. Part 2 was a multiple ascending dose study in patients with CHB randomized to receive RO7062931 at 0.5, 1.5, or 3.0 mg/kg or placebo every month for a total of 2 doses (Part 2a) or RO7062931 at 3.0 mg/kg every 2 weeks, 3.0 mg/kg every week (QW), or 4.0 mg/kg QW or placebo for a total of 3-5 doses (Part 2b). Sixty healthy volunteers and 59 patients received RO7062931 or placebo. The majority of adverse events (AEs) reported were mild in intensity. Common AEs included self-limiting injection site reactions and influenza-like illness. Supradose-proportional increases in RO7062931 plasma exposure and urinary excretion occurred at doses ≥3.0 mg/kg. In patients with CHB, RO7062931 resulted in dose-dependent and time-dependent reduction in HBsAg versus placebo. The greatest HBsAg declines from baseline were achieved with the 3.0 mg/kg QW dose regimen (mean nadir ~0.5 log10  IU/mL) independent of HBeAg status. CONCLUSIONS: RO7062931 is safe and well tolerated at doses up to 4.0 mg/kg QW. Supradose-proportional exposure at doses of 3.0-4.0 mg/kg was indicative of partial saturation of the ASGPR-mediated liver uptake system. Dose-dependent declines in HBsAg demonstrated target engagement with RO7062931.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of a TLR7 agonist prodrug RO6870868 in healthy volunteers.

RO6870868 is an oral prodrug of the toll-like receptor 7 (TLR7) specific agonist, RO6871765. TLR7 agonists augment host immune activity and are in development to treat hepatitis B infection. We evaluated the safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of RO6870868 in a first-in-human, phase I, randomized, single ascending oral dose study in 60 healthy volunteers at 6 dose levels (200-2000 mg). Single oral doses were generally well-tolerated with a predictable safety profile associated with dose-dependent increases in systemic interferon. No serious adverse events (AEs) were reported and no subject withdrew from the study due to an AE. No clinically significant changes were observed in vital signs, electrocardiograms, or laboratory parameters. Following oral RO6870868 doses, plasma RO6871765 concentrations increased rapidly, exhibiting mean terminal half-life ranging 2-6 h across all cohorts, with area under the plasma concentration versus time curve extrapolated to infinity (AUC0-∞ ) increasing proportionally with dose. A pattern of dose and time-dependent PD activity was demonstrated consistent with engagement of the TLR7 system. Single RO6870868 doses activated components of the TLR innate immune system in a dose-dependent manner with adequate safety and tolerability. Single-dose data in healthy volunteers are useful to evaluate safety, PK, and PD activity of TLR7 agonists and help to guide dose and regimen selection for further trials in patients with chronic hepatitis B.

A Single and Multiple Ascending Dose Study of Toll-Like Receptor 7 Agonist (RO7020531) in Chinese Healthy Volunteers.

Toll-like receptor 7 (TLR7) agonists modulate broad spectrum immune activity and are evaluated in the treatment of human diseases, including cancer and chronic viral infection. RO7020531, an oral prodrug of a TLR7 agonist, is in clinical development as part of a curative regimen against chronic hepatitis B. We report the safety, tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of RO7020531 in healthy Chinese volunteers following single and multiple ascending doses (SAD and MAD). PK and PD samples were evaluated from four SAD cohorts and 3 MAD cohorts with 10 subjects each (8 active and 2 placebo). Safety and tolerability were monitored throughout the study. A total of 155 adverse events (AEs) were reported in 49 subjects. Fifty-one AEs in 18 subjects were assessed as treatment-related. Most of the AEs were mild; nine subjects experienced moderate AEs; there were no severe AEs. In two 150 mg MAD cohorts given every other day (q.o.d.), 7 of 20 subjects experienced pyrexia and were discontinued due to transient asymptomatic lymphopenia, which resolved 24-48 hours postdose. The PK of the active metabolite, RO7011785, increased linearly with dose from 40 mg to 170 mg. There was no PK accumulation following q.o.d. dosing. The PK profile is consistent with observations in white subjects in the global first-in-human study. SADs and MADs of RO7020531 resulted in dose-dependent increases in TLR7 response markers at 100 mg or above. Flu-like symptoms were associated with higher interferon-α levels. RO7020531 was safe and acceptably tolerated in healthy Chinese volunteers with a multiple 150 mg q.o.d. dose regimen.

Clinical Pharmacokinetics of Vemurafenib.

Vemurafenib is an orally administered small-molecule inhibitor of the oncogenic BRAF kinase that is indicated for the treatment of patients with unresectable or metastatic melanoma harbouring BRAF V600 mutations. Vemurafenib is absorbed rapidly after a single oral dose of 960 mg, reaching maximum drug concentration approximately 4 h after administration. Extensive accumulation occurs after multiple dosing at 960 mg twice daily. Steady state is achieved after approximately 15-21 days and exposure at steady state is relatively constant. Population pharmacokinetic analysis identified a vemurafenib half-life of ≈57 h and elimination appears to be predominantly via the hepatic route. Pharmacokinetic parameters are generally consistent regardless of age, sex or race. No dose adjustments are necessary for patients with mild or moderate hepatic or renal impairment, but the effects of severe hepatic or renal impairment on vemurafenib pharmacokinetics are uncertain. Vemurafenib appears to be a substrate and inducer of cytochrome P450 (CYP) 3A4, a moderate inhibitor of CYP1A2 and both a substrate and inhibitor of the drug efflux transporters P-glycoprotein and breast cancer resistance protein. The relationship between plasma vemurafenib concentrations and response remains to be clarified.

Induction dosing of peginterferon alfa-2a (40 KD) and/or high-dose ribavirin in genotype 1 CHC patients with difficult-to-treat characteristics: pharmacokinetic and viral kinetic (PK/VK) assessment from PROGRESS.

BACKGROUND/AIMS: PROGRESS randomized chronic hepatitis C genotype 1 patients with a baseline viral load ≥400,000 IU/mL weighing ≥85 kg to regimens of 180 µg/week for 48 weeks or 360 µg/week for 12 weeks followed by 180 µg/week for 36 weeks peginterferon alfa-2a plus ribavirin. This analysis explored pharmacokinetics and early viral kinetics (VK) and evaluates differences between groups. METHODOLOGY: Blood samples for pharmacokinetic and VK analyses were collected from 51 patients enrolled in the PROGRESS study. RESULTS: Mean peginterferon alfa-2a trough concentration at week 12 was 11.7±4.3 ng/mL for 180 µg and 23.4±11.3 ng/mL for 360 µg. Early VK profiles suggested a trend towards an enhanced viral decline in the 360 µg groups with a mean decrease in HCV RNA at 48 hours post first dose of 1.04 log10 (IU/mL) compared with 0.76 log10 (IU/mL) in the 180 µg groups. Mean beta slope increased with dose, ranging from 0.38±0.26 log10 IU/week at 180 µg to 0.52±0.32 log10 IU/week at 360 µg. CONCLUSIONS: Early viral de clines may be enhanced with the 360 µg dose. These data may suggest the utility of high-dose peginterfer on alfa-2a plus direct-acting antivirals (DAA) in select difficult-to-treat populations.

A single-dose mass balance and metabolite-profiling study of vemurafenib in patients with metastatic melanoma.

Vemurafenib, a selective inhibitor of oncogenic BRAF kinase carrying the V600 mutation, is approved for treatment of advanced BRAF mutation-positive melanoma. This study characterized mass balance, metabolism, rates/routes of elimination, and disposition of (14)C-labeled vemurafenib in patients with metastatic melanoma. Seven patients with metastatic BRAF-mutated melanoma received unlabeled vemurafenib 960 mg twice daily for 14 days. On the morning of day 15, patients received (14)C-labeled vemurafenib 960 mg (maximum 2.56 MBq [69.2 µCi]). Thereafter, patients resumed unlabeled vemurafenib (960 mg twice daily). Blood, urine, and feces were collected for metabolism, pharmacokinetic, and dose recovery analysis. Within 18 days after dose, ∽95% of (14)C-vemurafenib-related material was recovered from feces (94.1%) and urine (<1%). The parent compound was the predominant component (95%) in plasma. The mean plasma elimination half-life of (14)C-vemurafenib-related material was 71.1 h. Each metabolite accounted for <0.5% and ≤6% of the total administered dose in urine and feces, respectively (0-96 h postdose). No new metabolites were detected. Vemurafenib was well-tolerated. Excretion of vemurafenib via bile into feces is considered the predominant elimination route from plasma with minor renal elimination (<1%). e00113.

A phase 2 trial of R1507, a monoclonal antibody to the insulin-like growth factor-1 receptor (IGF-1R), in patients with recurrent or refractory rhabdomyosarcoma, osteosarcoma, synovial sarcoma, and other soft tissue sarcomas: results of a Sarcoma Alliance for Research Through Collaboration study.

BACKGROUND: Insulin-like growth factor-1 receptor (IGF-1R) is implicated in the pathogenesis of rhabdomyosarcoma (RMS), osteosarcoma (OS), and synovial sarcoma (SS). The authors conducted a multi-institutional phase 2 trial of the monoclonal antibody R1507 in patients with various subtypes of recurrent or refractory sarcomas. METHODS: Eligibility criteria included age ≥ 2 years and a diagnosis of recurrent or refractory RMS, OS, SS, and other soft tissue sarcomas. Patients received a weekly dose of 9 mg/kg R1507 intravenously. The primary endpoint was the best objective response rate using World Health Organization criteria. Tumor imaging was performed every 6 weeks × 4 and every 12 weeks thereafter. RESULTS: From December 2007 through August 2009, 163 eligible patients from 33 institutions were enrolled. The median patient age was 31 years (range, 7-85 years). Histologic diagnoses included OS (n = 38), RMS (n = 36), SS (n = 23), and other sarcomas (n = 66). The overall objective response rate was 2.5% (95% confidence interval, 0.7%-6.2%). Partial responses were observed in 4 patients, including 2 patients with OS, 1 patient with RMS, and 1 patient with alveolar soft part sarcoma. Four additional patients (3 with RMS and 1 with myxoid liposarcoma) had a ≥ 50% decrease in tumor size that lasted for <4 weeks. The median progression-free survival was 5.7 weeks, and the median overall survival was 11 months. The most common grade 3/4 toxicities were metabolic (12%), hematologic (6%), gastrointestinal (4%), and general constitutional symptoms (8%). CONCLUSIONS: R1507 is safe and well tolerated but has limited activity in patients with recurrent or refractory bone and soft tissue sarcomas. Additional studies to help identify the predictive factors associated with clinical benefit in selected histologies such as RMS appear to be warranted.

The effects of a high-fat meal on single-dose vemurafenib pharmacokinetics.

Vemurafenib is an orally bioavailable BRAF inhibitor approved for the treatment of BRAF(V600) -mutant metastatic melanoma. It is important to understand the effects of a high-fat meal on the pharmacokinetics (PK) of vemurafenib in humans because it is a Biopharmaceutics Classification System Class IV drug and its PK can be altered by food. An open-label, multicenter, randomized, 2-period crossover study was performed to evaluate the effect of food (high-fat meal) on the PK of a single oral dose of vemurafenib. Secondary objectives were safety and tolerability, efficacy with best overall response rate, and overall survival during the treatment period. The concomitant intake of food (high-fat meal) increased mean Cmax 3.5 to 7.5 µg/mL and mean AUC0-∞ 119 to 360 µg·h/mL after a single 960 mg dose of vemurafenib (N = 13-15 patients). An effect of food on single-dose exposure is suggested by point estimates and 90% CI of geometric mean ratios for vemurafenib plasma AUC0-∞ (4.7) and Cmax (2.5). Toxicity and response rate of vemurafenib in this study were consistent with prior experience in patients with BRAF(V600) -mutant metastatic melanoma. A high-fat meal increased the exposure to vemurafenib without altering the mean terminal half-life.

Analysis of dermatologic events in vemurafenib-treated patients with melanoma.

BACKGROUND: Vemurafenib has been approved for the treatment of patients with advanced BRAF(V600E)-mutant melanoma. This report by the Vemurafenib Dermatology Working Group presents the characteristics of dermatologic adverse events (AEs) that occur in vemurafenib-treated patients, including cutaneous squamous cell carcinoma (cuSCC). METHODS: Dermatologic AEs were assessed from three ongoing trials of BRAF(V600E) mutation-positive advanced melanoma. Histologic central review and genetic characterization were completed for a subset of cuSCC lesions. RESULTS: A total of 520 patients received vemurafenib. The most commonly reported AEs were dermatologic AEs, occurring in 92%-95% of patients. Rash was the most common AE (64%-75% of patients), and the most common types were rash not otherwise specified, erythema, maculopapular rash, and folliculitis. Rash development did not appear to correlate with tumor response. Photosensitivity occurred in 35%-63% of patients, and palmar-plantar erythrodysesthesia (PPE) occurred in 8%-10% of patients. The severity of rash, photosensitivity, and PPE were mainly grade 1 or 2. In all, 19%-26% of patients developed cuSCC, mostly keratoacanthomas (KAs). The majority of patients with cuSCC continued therapy without dose reduction after resection. Genetic analysis of 29 cuSCC/KA samples demonstrated HRAS mutations in 41%. CONCLUSIONS: Dermatologic AEs associated with vemurafenib treatment in patients with melanoma were generally manageable with supportive care measures. Dose interruptions and/or reductions were required in <10% of patients.

Improved human bioavailability of vemurafenib, a practically insoluble drug, using an amorphous polymer-stabilized solid dispersion prepared by a solvent-controlled coprecipitation process.

The present work deals with improving the solubility of vemurafenib, a practically insoluble drug, by converting it into an amorphous-solid dispersion using a solvent-controlled precipitation process. The dispersion containing vemurafenib and hypromellose acetate succinate (HPMCAS), an enteric polymer, is termed microprecipitated bulk powder (MBP), in which the drug is uniformly dispersed within the polymeric substrate. HPMCAS was found to be the most suitable polymer for vemurafenib MBP, among a series of enteric polymers based on superior physical stability and drug-release characteristics of the MBP. The MBP provided a greater rate and extent of dissolution than crystalline drug, reaching an apparent drug concentration of 28-35 µg/mL, almost 30-fold higher than solubility of crystalline drug at 1 µg/mL. The supersaturation was also maintained for more than 4 h. Upon exposure to high temperature and humidity, the MBP was destabilized, resulting in crystallization and lower dissolution rate. The control of moisture and temperature is essential to maintain the stability of the MBP. In a relative human bioavailability study, vemurafenib MBP provided a four- to fivefold increase in exposure compared with crystalline drug. Improving solubility with an amorphous-solid dispersion is a viable strategy for the development of practically insoluble compounds.

Effect of peginterferon alfa-2a (40KD) on cytochrome P450 isoenzyme activity.

AIM: Pegylated interferon-based therapy is recommended for treatment of hepatitis C virus (HCV) infection. Because interferons are known to down-regulate hepatic cytochrome P450 (CYP) enzymes, which are involved in drug metabolism and clearance, there is a need to investigate the effect of peginterferon (PEG-IFN) alfa-2a (40KD) on the activity of these enzymes in vivo. METHODS: Fourteen healthy, male volunteers aged 18 to 45 years were recruited into an open label, two period, single centre study in which CYP enzyme activity was measured by administration of the selectively metabolized probe drugs theophylline (CYP1A2), tolbutamide (CYP2C9), mephenytoin (CYP2C19), debrisoquine (CYP2D6) and dapsone (CYP3A4) on day 1 of the study. PEG-IFN alfa-2a (40KD) 180 µg was given subcutaneously each week from day 15 to 36, and probe drugs were re-administered on day 37. Probe drugs and metabolites were quantified in plasma or urine samples and used to derive pharmacokinetic parameters. RESULTS: PEG-IFN alfa-2a (40KD) significantly increased the area under the serum drug concentration vs. time curve (AUC(0,∞)) for theophylline by 24%, with a reduction in the mean oral clearance of theophylline of 20%. There were no effects on the pharmacokinetics of any of the other probe drugs. The incidence of adverse events was as expected in subjects receiving pegylated interferon. CONCLUSION: These results suggest there may be an inhibitory effect of PEG-IFN alfa-2a (40KD) on CYP1A2. PEG-IFN alfa-2a (40KD) had no effect on CYP2C9, CYP2C19, CYP2D6 or CYP3A4 in healthy subjects.

Evaluation of the absolute bioavailability of pegylated interferon alfa-2a after subcutaneous administration to healthy male volunteers: an open-label, randomized, parallel-group study.

BACKGROUND: Interferon (IFN)-based therapy is the recommended treatment for hepatitis C virus. Because pegylated IFN (PEG-IFN) alfa-2a is administered subcutaneously, it is of interest to determine the proportion of the dose that is absorbed from the subcutaneous (SC) tissue and ultimately reaches systemic circulation. OBJECTIVE: The goal of this study was to characterize the absolute bioavailability of PEG-IFN alfa-2a (40 kDa) after SC dosing (180 µg) and to evaluate the pharmacokinetics of PEG-IFN alfa-2a after intravenous (IV) and SC administration. METHODS: In this parallel-group study, 18 participants were given a single IV dose of PEG-IFN alfa-2a 90 µg and 18 participants received PEG-IFN alfa-2a 180 µg SC. Serum concentrations of PEG-IFN alfa-2a were measured predose and serially until 312 hours after the first dose. Pharmacokinetic parameters (CL/F, volume of distribution, C(max), and T(max)) were estimated using noncompartmental methods. Bioavailability was calculated by using the following formula: (AUC(SC)/AUC(IV)) · (dose(IV)/dose(SC)). RESULTS: Eighteen healthy males received IV PEG-IFN alfa-2a, and an additional 18 healthy males received SC PEG-IFN alfa-2a. Subjects in each group had comparable mean weight, height, and body mass index. After IV administration of PEG-IFN alfa-2a (90 µg), there was a slow decline in serum concentration, the mean rate of systemic clearance was low at 126 mL/h, and the estimated mean volume of distribution at steady state was 9 L. After SC administration of PEG-IFN alfa-2a 180 µg, absorption was sustained, with mean T(max) occurring 102 hours after administration. The mean absolute bioavailability was 84%. A higher rate of influenza-like symptoms was observed after IV administration, along with decreased neutrophil counts, compared with subjects who underwent SC dosing. CONCLUSIONS: Approximately 84% of a SC-administered dose of PEG-IFN alfa-2a reached the systemic circulation in these male healthy volunteers. The slow absorption, restricted distribution, and slow elimination of PEG-IFN alfa-2a resulted in sustained serum levels throughout the 7-day dosing interval.

Discovery of piragliatin--first glucokinase activator studied in type 2 diabetic patients.

Glucokinase (GK) activation as a potential strategy to treat type 2 diabetes (T2D) is well recognized. Compound 1, a glucokinase activator (GKA) lead that we have previously disclosed, caused reversible hepatic lipidosis in repeat-dose toxicology studies. We hypothesized that the hepatic lipidosis was due to the structure-based toxicity and later established that it was due to the formation of a thiourea metabolite, 2. Subsequent SAR studies of 1 led to the identification of a pyrazine-based lead analogue 3, lacking the thiazole moiety. In vivo metabolite identification studies, followed by the independent synthesis and profiling of the cyclopentyl keto- and hydroxyl- metabolites of 3, led to the selection of piragliatin, 4, as the clinical lead. Piragliatin was found to lower pre- and postprandial glucose levels, improve the insulin secretory profile, increase ß-cell sensitivity to glucose, and decrease hepatic glucose output in patients with T2D.

2,3-Disubstituted acrylamides as potent glucokinase activators.

The phenylacetamide 1 represents the archtypical glucokinase activator (GKA) in which only the R-isomer is active. In order to probe whether the chiral center could be replaced, we prepared a series of olefins 2 and show in the present work that these compounds represent a new class of GKAs. Surprisingly, the SAR of the new series paralleled that of the saturated derivatives with the exception that there was greater tolerance for larger alkyl and cycloalkyl groups at R(2) region in comparison to the phenylacetamides. In normal Wistar rats, the 2,3-disubstituted acrylamide analog 10 was well absorbed and demonstrated robust glucose lowering effects.

Inhibition of mutated, activated BRAF in metastatic melanoma.

BACKGROUND: The identification of somatic mutations in the gene encoding the serine-threonine protein kinase B-RAF (BRAF) in the majority of melanomas offers an opportunity to test oncogene-targeted therapy for this disease. METHODS: We conducted a multicenter, phase 1, dose-escalation trial of PLX4032 (also known as RG7204), an orally available inhibitor of mutated BRAF, followed by an extension phase involving the maximum dose that could be administered without adverse effects (the recommended phase 2 dose). Patients received PLX4032 twice daily until they had disease progression. Pharmacokinetic analysis and tumor-response assessments were conducted in all patients. In selected patients, tumor biopsy was performed before and during treatment to validate BRAF inhibition. RESULTS: A total of 55 patients (49 of whom had melanoma) were enrolled in the dose-escalation phase, and 32 additional patients with metastatic melanoma who had BRAF with the V600E mutation were enrolled in the extension phase. The recommended phase 2 dose was 960 mg twice daily, with increases in the dose limited by grade 2 or 3 rash, fatigue, and arthralgia. In the dose-escalation cohort, among the 16 patients with melanoma whose tumors carried the V600E BRAF mutation and who were receiving 240 mg or more of PLX4032 twice daily, 10 had a partial response and 1 had a complete response. Among the 32 patients in the extension cohort, 24 had a partial response and 2 had a complete response. The estimated median progression-free survival among all patients was more than 7 months. CONCLUSIONS: Treatment of metastatic melanoma with PLX4032 in patients with tumors that carry the V600E BRAF mutation resulted in complete or partial tumor regression in the majority of patients. (Funded by Plexxikon and Roche Pharmaceuticals.)

Piragliatin (RO4389620), a novel glucokinase activator, lowers plasma glucose both in the postabsorptive state and after a glucose challenge in patients with type 2 diabetes mellitus: a mechanistic study.

CONTEXT: Glucokinase plays a key role in glucose homeostasis. Glucokinase activators can lower glucose levels in both animal and human type 2 diabetes, but their mechanism of action has never been explored in humans. OBJECTIVE: The objective of the study was to investigate the effects of the glucokinase activator piragliatin (RO4389620) on ß-cell function and glucose fluxes in both fasting and fed (oral glucose tolerance test) states in patients with type 2 diabetes. DESIGN: This was a phase Ib randomized, double-blind, placebo-controlled crossover trial of two (25 and 100 mg) doses of piragliatin. SETTING: This study was conducted at a clinical research center. PATIENTS: Patients included 15 volunteer ambulatory patients with mild type 2 diabetes. INTERVENTIONS: Interventions included three 10-h (-300' to +300') studies, with an interval of at least 14 d. Administration of a single dose of placebo or piragliatin 25 mg or piragliatin 100 mg at -120'. Oral glucose tolerance test (at 0') with dual (iv and oral routes) tracer dilution technique was conducted. MAIN OUTCOME MEASURES: The primary measure was plasma glucose concentration. The secondary measure was model assessed ß-cell function and tracer-determined glucose fluxes. RESULTS: Piragliatin caused a dose-dependent reduction of glucose levels in both fasting and fed states (P < 0.01). In the fasting state, piragliatin caused a dose-dependent increase in ß-cell function, a fall in endogenous glucose output, and a rise in glucose use (all P < 0.01). In the fed state, the primary effects of piragliatin were on ß-cell function (P < 0.01). CONCLUSIONS: The glucokinase activator piragliatin has an acute glucose-lowering action in patients with mild type 2 diabetes, mainly mediated through a generalized enhancement of ß-cell function and through fasting restricted changes in glucose turnover.

RG7204 (PLX4032), a selective BRAFV600E inhibitor, displays potent antitumor activity in preclinical melanoma models.

The BRAF(V600E) mutation is common in several human cancers, especially melanoma. RG7204 (PLX4032) is a small-molecule inhibitor of BRAF(V600E) kinase activity that is in phase II and phase III clinical testing. Here, we report a preclinical characterization of the antitumor activity of RG7204 using established in vitro and in vivo models of malignant melanoma. RG7204 potently inhibited proliferation and mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase and ERK phosphorylation in a panel of tumor cell lines, including melanoma cell lines expressing BRAF(V600E) or other mutant BRAF proteins altered at codon 600. In contrast, RG7204 lacked activity in cell lines that express wild-type BRAF or non-V600 mutations. In several tumor xenograft models of BRAF(V600E)-expressing melanoma, we found that RG7204 treatment caused partial or complete tumor regressions and improved animal survival, in a dose-dependent manner. There was no toxicity observed in any dose group in any of the in vivo models tested. Our findings offer evidence of the potent antitumor activity of RG7204 against melanomas harboring the mutant BRAF(V600E) gene.

Discovery, structure-activity relationships, pharmacokinetics, and efficacy of glucokinase activator (2R)-3-cyclopentyl-2-(4-methanesulfonylphenyl)-N-thiazol-2-yl-propionamide (RO0281675).

Glucokinase (GK) is a glucose sensor that couples glucose metabolism to insulin release. The important role of GK in maintaining glucose homeostasis is illustrated in patients with GK mutations. In this publication, identification of the hit molecule 1 and its SAR development, which led to the discovery of potent allosteric GK activators 9a and 21a, is described. Compound 21a (RO0281675) was used to validate the clinical relevance of targeting GK to treat type 2 diabetes.