The Inhibition of Protein Kinase C ß Contributes to the Pathogenesis of Preeclampsia by Activating Autophagy.

BACKGROUND: Preeclampsia is a devastating hypertensive disorder of pregnancy with unknown mechanism. Recent studies have considered abnormal autophagy as a new cellular mechanism for this disorder, while little is known about how autophagy is specifically involved and what factors are implicated. Here, we report a previously unrecognized preeclampsia-associated autophagic regulator, PKCß, that is involved in placental angiogenesis. METHODS: PKCß levels were evaluated by quantitative real-time PCR, western blotting, immunofluorescence and by the analysis of public data. The autophagy-regulating role of PKCß inhibition in preeclampsia pathogenesis was studied in a mouse model, and in human umbilical vein endothelial cells (HUVECs) and human choriocarcinoma cells (JEG-3). FINDINGS: PKCß was significantly downregulated in human preeclamptic placentas. In a mouse model, the selective inhibition of PKCß by Ruboxistaurin was sufficient to induce preeclampsia-like symptoms, accompanied by excessive autophagic flux and a disruption in the balance of pro- and anti-angiogenic factors in mouse placentas. In contrast, autophagic inhibition by 3-methyladenine partially normalized hypertension, proteinuria and placental angiogenic imbalance in PKCß-inhibited mice. Our in vitro experiments demonstrated that PKCß inhibition activated autophagy, thus blocking VEGFA-induced HUVEC tube formation and resulting in the significant upregulation of sFLT1 and downregulation of VEGFA in JEG-3 cells. INTERPRETATION: These data support a novel model in which autophagic activation due to PKCß inhibition leads to the impairment of angiogenesis and eventually results in preeclampsia. FUNDING: Shanghai Key Program of Clinical Science and Technology Innovation, National Natural Science Foundation of China and Shanghai Medical Center of Key Programs for Female Reproductive Diseases.

Comparison of established and novel methods for the detection and enumeration of microparticles in canine stored erythrocyte concentrates for transfusion.

BACKGROUND: Microparticles (MP) are submicron, phosphatidylserine (PS)-bearing lipid vesicles with physiologic and pathologic roles in coagulation and inflammation. Microparticles accumulate in packed RBC (pRBC) stored for transfusion, potentially increasing recipient morbidity. Historically, canine MP have been detected with the PS label annexin V in supernatant samples. Other detection methods are available but have not been evaluated in dogs. OBJECTIVES: The purpose of the study was to detect and enumerate MP in canine pRBC using annexin V, lactadherin, and bio-maleimide to compare label performance and assess microparticle accumulation under standard storage conditions. METHODS: Microparticles (0.5-1.0 µm) in canine dog erythrocyte antigen 1.1 positive, nonleukoreduced pRBC were labeled with FITC-annexin V, FITC-lactadherin, and the fluorescent dye bio-maleimide, and were counted using flow cytometry at 3 time points (days 7, 21, and 35) of storage. Unprocessed pRBC, rather than supernatant, were used. RESULTS: Annexin V and bio-maleimide labeling produced comparable microparticle counts (P = .16), while lactadherin labeling resulted in higher microparticle counts than annexin V (P = .002) and bio-maleimide (P = .006), particularly on day 7. Bio-maleimide- and annexin V-based microparticle counts increased significantly from day 7 to 35 (P = .04), and increases from day 21 to 35 approached statistical significance (P = .05). CONCLUSIONS: Bio-maleimide- and annexin V-mediated microparticle counts were comparable in unprocessed canine pRBC using flow cytometry. Whether the increased microparticle counts with lactadherin were due to increased sensitivity for small, PS-bearing MP or due to labeling of membrane fragments and debris requires further investigation.

Glycogen Synthase Kinase 3 Inactivation Drives T-bet-Mediated Downregulation of Co-receptor PD-1 to Enhance CD8(+) Cytolytic T Cell Responses.

Despite the importance of the co-receptor PD-1 in T cell immunity, the upstream signaling pathway that regulates PD-1 expression has not been defined. Glycogen synthase kinase 3 (GSK-3, isoforms α and ß) is a serine-threonine kinase implicated in cellular processes. Here, we identified GSK-3 as a key upstream kinase that regulated PD-1 expression in CD8(+) T cells. GSK-3 siRNA downregulation, or inhibition by small molecules, blocked PD-1 expression, resulting in increased CD8(+) cytotoxic T lymphocyte (CTL) function. Mechanistically, GSK-3 inactivation increased Tbx21 transcription, promoting enhanced T-bet expression and subsequent suppression of Pdcd1 (encodes PD-1) transcription in CD8(+) CTLs. Injection of GSK-3 inhibitors in mice increased in vivo CD8(+) OT-I CTL function and the clearance of murine gamma-herpesvirus 68 and lymphocytic choriomeningitis clone 13 and reversed T cell exhaustion. Our findings identify GSK-3 as a regulator of PD-1 expression and demonstrate the applicability of GSK-3 inhibitors in the modulation of PD-1 in immunotherapy.

Combination of long-acting HIV fusion inhibitor albuvirtide and LPV/r showed potent efficacy in HIV-1 patients.

BACKGROUND: Long acting antiretroviral drugs represent a promising approach for chronic treatment of HIV infection. Here, we study the efficacy and safety of albuvirtide (ABT), an HIV-1 fusion inhibitor with a half life of 11-12 days in human. METHODS: ABT was evaluated in a 7-week, open-label and randomized trial, combining with LPV/r. Twenty HIV-1-infected adults were assigned to two dose groups, receiving ABT (160 or 320 mg) given weekly and LPV/r given twice daily. RESULTS: At week 7, the decline of HIV-1 RNA from baseline was 1.9 (1.3-2.3) log10 and 2.2 (1.6-2.7) log10 copies/ml, and suppression of HIV-1 RNA to below 50 copies/ml was achieved in 11.1 % (1/9) and 55.6 % (5/9) patients, for the 160 and 320 mg dose group respectively. CONCLUSION: A clear dose-efficacy correlation of ABT was demonstrated. ABT combining with LPV/r is a promising two-drug regimen to be tested in larger patient population.

Oral protein kinase c ß inhibition using ruboxistaurin: efficacy, safety, and causes of vision loss among 813 patients (1,392 eyes) with diabetic retinopathy in the Protein Kinase C ß Inhibitor-Diabetic Retinopathy Study and the Protein Kinase C ß Inhibitor-Diabetic Retinopathy Study 2.

PURPOSE: To evaluate efficacy, safety, and causes of vision loss among 813 patients (1,392 eyes) with moderately severe to very severe nonproliferative diabetic retinopathy from the Protein Kinase C ß Inhibitor-Diabetic Retinopathy Study and Protein Kinase C ß Inhibitor-Diabetic Retinopathy Study 2 ruboxistaurin (RBX) protein kinase C ß inhibitor trials. METHODS: Patients in these 3-year, randomized, placebo-controlled, double-masked, Phase 3 trials had best-corrected Early Treatment Diabetic Retinopathy Study visual acuity ≥45 letters (∼20/125 Snellen), Early Treatment Diabetic Retinopathy Study retinopathy level 47A/B-53E, and no previous panretinal photocoagulation in ≥1 eye. Patients received placebo (N = 401) or RBX 32 mg/day (N = 412). Data from the 2 studies were combined and masked evaluation of retinal photographs was performed for cause of visual decline in all patients experiencing sustained moderate visual loss (≥15-letter loss sustained for the last 6 months of study). RESULTS: In the studies combined, sustained moderate visual loss occurred in 10.2% of placebo-treated patients versus 6.1% of RBX-treated patients (P = 0.011). A ≥15-letter gain occurred in 2.4% of placebo versus 4.7% of RBX eyes (P = 0.021) and a ≥15-letter loss occurred in 11.4% versus 7.4%, respectively (P = 0.012). Diabetic macular edema was the probable primary cause of vision loss. Among eyes without focal/grid photocoagulation at baseline, fewer RBX group eyes (26.7%) required initial focal/grid photocoagulation versus placebo (35.6%; P = 0.008). No safety concerns were identified. CONCLUSION: Analysis of data combined from two similar studies adds further statistical significance to RBX's beneficial effects on visual loss, need for focal laser, and vision gain, most likely through effects on macular edema.

Evaluation of MP4OX for prevention of perioperative hypotension in patients undergoing primary hip arthroplasty with spinal anesthesia: a randomized, double-blind, multicenter study.

BACKGROUND: MP4OX (oxygenated polyethylene glycol-modified hemoglobin) is an oxygen therapeutic agent with potential applications in clinical settings where targeted delivery of oxygen to ischemic tissues is required. The primary goal of this study was to investigate MP4OX for preventing hypotensive episodes. An additional goal was to establish the safety profile of MP4OX in a large surgical population. METHODS: Patients (n = 367) from 18 active study sites in six countries, undergoing elective primary hip arthroplasty with spinal anesthesia, were randomized to receive MP4OX or hydroxyethyl starch 130/0.4. Patients received a 250-ml dose at induction of spinal anesthesia and a second 250-ml dose if the protocol-specified trigger (predefined decrease in systolic blood pressure) was reached. The primary end point was the proportion of patients who developed one or more hypotensive episodes. RESULTS: The proportion of patients with one or more hypotensive episodes was significantly lower (P < 0.0001) in the MP4OX group (66.1%) versus controls receiving hydroxyethyl starch 130/0.4 (90.2%). More MP4OX-treated patients experienced adverse events compared with controls (72.7% vs. 61.4%; P = 0.026). Transient elevations in laboratory values (e.g., alanine aminotransferase, aspartate aminotransferase, lipase, and troponin concentrations) occurred more frequently in the MP4OX group. There were no significant differences in the incidence of serious adverse events or in the composite morbidity and ischemia outcome end points, but nausea and hypertension were reported more often in MP4OX-treated patients. CONCLUSION: MP4OX significantly reduced the incidence of hypotensive episodes in patients undergoing hip arthroplasty, but the adverse event profile does not support use in routine low-risk surgical patients for the indication evaluated in this study.

[State of the liver antioxidant system and content of matrix metalloproteinase-2 of the large intestine under the effect of maleimide derivative in experimental colorectal carcinogenesis in rats].

The maleimide derivative--1-(4-Cl-benzyl)-3-Cl-4-(CF3-phenylamino)-1H-pyrrol-2.5-dione (MI-1) with cytostatic activity did not cause substantial changes of liver antioxidant system and level of matrix metalloproteinase-2 in intestinal mucosa after chronic treatment (for 20 weeks). MI-1 did not cause significant changes in the content of thiobarbituric-active products and plasma membrane protein carbonyl groups in the rat liver. However activities of superoxide dismutase, glutathione peroxidase, and content of reduced glutathione were decreased in both doses--0.027 and 2.7 mg/kg. The level of matrix metalloproteinase-2 in intestinal mucosa was decreased just in maximum dose--2.7 mg/kg. The contents of thiobarbituric-active products, protein carbonyl groups, reduced glutathione, matrix metalloproteinase-2, activities of glutathione peroxidase and glutathione-S-transferase in the liver cells have increased in 1.2-dimethylhydrazine-induced colon cancer in rats. The activities of enzymes of the first line of antioxidant defense--superoxide dismutase and catalase were decreased to 40%. The maleimide derivative prevents development of oxidation stress and partially reduce them to control level.

[Effect of maleimide derivative on the morpho-functional state of the kidney in experimental colon carcinogenesis in rats].

The effect of long-term administration of the novel maleimide derivative with antiproliferative activity on kidney morpho-functional state in experimental (1,2-dimethylhydrazine-induced) colon carcinogenesis has been investigated on 60 male rats. 1,2-Dimethylhydrazine was injected subcutaneously in dose 20 mg/kg one time per week during 20 weeks. Maleimide derivative in dose of 0,027 and 2,7 mg/kg was given per os daily during the same time. The state of kidneys was evaluated after morphometrical investigation and measurement of urea, creatinine and chlorides levels in blood serum. It hasn't been revealed significant structure-functional changes in kidneys after daily administration during 20 weeks. The induction of proliferate activity of distal tubules epithelial cells and reducing of epithelial layer thickness in proximal tubules in kidneys in rats with experimental carcinogenesis has been observed. In experimental colon carcinogenesis, maleimide derivative displays some protective action to tubular apparatus of rat's kidney cortical nephrons and reduces the frequency of preneoplastic changes in tubules epithelial cells.

Ruboxistaurin mesilate hydrate for diabetic retinopathy.

Diabetic retinopathy remains a major worldwide cause of preventable blindness. The beta isoform of protein kinase C (PKC) may play an important role in the pathogenesis of this disorder. Ruboxistaurin mesylate hydrate is an orally bioavailable, highly-specific inhibitor of PKC beta, which has shown some efficacy in several large, multicenter, randomized clinical trials. The U.S. Food and Drug Administration issued an approvable letter for ruboxistaurin in 2006, but at this time the medication is not available for routine clinical use.

Haemoglobin-based oxygen carriers: is the benefit worth the risk?

When blood is indicated but not available, haemoglobin-based oxygen carriers can sustain oxygen carriage in acute anaemia, expand circulating volume and improve rheology to ischaemic tissues. When blood is limited, not available or not an option, the risks associated with these carriers must be weighed against the risk of death.

GSK3 inhibitors show benefits in an Alzheimer's disease (AD) model of neurodegeneration but adverse effects in control animals.

The dysregulation of glycogen synthase kinase-3 (GSK3) has been implicated in Alzheimer disease (AD) pathogenesis and in Abeta-induced neurotoxicity, leading us to investigate it as a therapeutic target in an intracerebroventricular Abeta infusion model. Infusion of a specific GSK3 inhibitor SB216763 (SB) reduced a downstream target, phospho-glycogen synthase 39%, and increased glycogen levels 44%, suggesting effective inhibition of enzyme activity. Compared to vehicle, Abeta increased GSK3 activity, and was associated with elevations in levels of ptau, caspase-3, the tau kinase phospho-c-jun N-terminal kinase (pJNK), neuronal DNA fragmentation, and gliosis. Co-infusion of SB corrected all responses to Abeta infusion except the induction of gliosis and behavioral deficits in the Morris water maze. Nevertheless, SB alone was associated with induction of neurodegenerative markers and behavioral deficits. These data support a role for GSK3 hyperactivation in AD pathogenesis, but emphasize the importance of developing inhibitors that do not suppress constitutive activity.

[Evaluation of hepatotoxicity of novel maleimide derivative with cytostatic activity and its effect on peroxidation process and antioxidant system in the liver].

Novel maleimide derivative 1-(4-Cl-benzyl)-3-Cl-4-(CF3-phenylamino)-1H-pyrrol-2.5-dione (MI-1) with cytostatic activity does not damage rat liver cells after intragastric administration. It is confirmed by alanine- and aspartate aminotransferase, lactate dehydrogenase and alkaline phosphatase activities in blood serum. Preliminary treatment with MI-1 partially prevents from liver cell damage caused by CoCl2. the content of thiobarbituric-active products, protein carbonyl groups, reduced glutathione and activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in the liver cell after one- and ten-days treatment with novel maleimide derivative have been studied. It has been determined that one-day administration of MI-1 has not caused significant changes of peroxidation process and antioxidant system in the liver cells. After ten days treatment the activity of glutathione-S-transferase has been increased, superoxide dismutase--two times decreased, but other parameters have not been significantly changed. Ten days injection of CoCl2 provokes some manifestations of oxidative stress in the liver cells that has been partially leveled by preliminary treatment with maleimide derivative.

Pharmacokinetics and tolerability of a novel long-acting glucagon-like peptide-1 analog, CJC-1131, in healthy and diabetic subjects.

OBJECTIVE: The safety, tolerability, pharmacokinetics and preliminary pharmacodynamics of single rising doses of a novel GLP-1 analog, CJC-1131, was evaluated. METHODS: CJC-1131 was subcutaneously injected in 8 groups (1.5 - 20.5 microg/kg) of healthy subjects (each group of six subjects included 1 placebo per dose level). CJC-1131 was also injected subcutaneously in 6 groups (1.5 - 12 microg/kg) of Type 2 diabetic patients after a 9-day washout period from their own anti-diabetic medication. Each group of 8 patients included 2 placebo-treated patients. Seven blood glucose measurements were taken daily, and meal tolerance tests were performed on the day before dosing and on Day 3. RESULTS: CJC-1131 was quickly absorbed from the subcutaneous space, and a less than dose-proportional increase was found in Cmax. The half-life of CJC-1131 varied from 8.9 - 14.7 days in healthy subjects and from 9.1 - 13.8 days in patients. The maximum tolerated dose in healthy subjects was established at 12 microg/kg with nausea and vomiting being the dose-limiting events. These events occurred generally in the morning after dosing. Blood glucose levels in patients decreased on Day 1 in proportion with dose, with a maximum average decrease of 4.1 mmol/l in the highest dose group. Higher doses appeared to be related to a slight weight loss in patients. CONCLUSIONS: Conjugation to albumin led to a major prolongation of the half-life of GLP-1. The tolerability of this potential antidiabetic drug seems to be limited only by gastrointestinal complaints.

Ruboxistaurin: LY 333531.

Ruboxistaurin, an orally active protein kinase C beta (PKC beta) inhibitor, is a macrocyclic bisindolylmaleimide compound under development by Eli Lilly with potential as a therapy for diabetic macular oedema and other diabetic angiopathies, including diabetic retinopathy, diabetic peripheral neuropathy and diabetic nephropathy. Ruboxistaurin is awaiting approvals in the US and Europe for the treatment of diabetic retinopathy. Eli Lilly and Alcon entered into a long-term agreement to co-promote ruboxistaurin in the US and Puerto Rico for diabetic retinopathy. The agreement is subject to the US FDA's approval of the agent for this indication. Under the terms of the agreement, Alcon will assume primary responsibility for promotion to eye specialists including retinal specialists and general ophthalmologists, while Eli Lilly will be targeting endocrinologists and physicians. Subject to approval in the US, Eli Lilly will receive milestone and marketing payments from Alcon. Alcon in turn will receive compensation based on product sales. In December 2003, Eli Lilly signed a joint development and co-marketing agreement with Takeda Chemical Industries for ruboxistaurin in the Japanese market. Under the terms of the agreement, Eli Lilly Japan and Takeda will jointly develop ruboxistaurin in Japan, will file an NDA for diabetic peripheral neuropathy and diabetic retinopathy, and subsequently will market the drug in Japan. Ruboxistaurin was submitted for approval in Europe in the second quarter of 2006. The agent is also in phase II studies for the treatment of diabetic maculopathy (macular retinopathy) in Japan. Data from a phase III, 3-year study of ruboxistaurin in patients with moderate to severe diabetic retinopathy showed that ruboxistaurin markedly reduced the risk of sustained vision loss compared with placebo. This multicentre, randomised study, named PKC-DRS2 (Protein Kinase C-Diabetic Retinopathy Study 2), was conducted at 70 clinical sites and involved 685 patients with diabetic retinopathy. The agent is also in a phase II study in the US, Canada and Europe in patients with clinically significant macular oedema. The trial (B7A-MC-MBCU), which will evaluate oral administration of the drug using optical coherence tomography over a period of 18 months, is expected to enrol approximately 220 patients. This randomised, double-blind, placebo-controlled study was initiated in August 2005 and is expected to be completed in March 2008. Previously, results of the PKC-Diabetic Retinopathy Study (PKC-DRS) showed that ruboxistaurin at a dose of 32 mg/day has potential to reduce the risk of moderate vision loss especially in patients with diabetic macular oedema. This phase III, randomised, double-blind, multidose study in 252 patients with type 1 and type 2 diabetes receiving ruboxistaurin or placebo for 3-4 years evaluated the safety of the agent and its effect on progression of diabetic retinopathy, moderate vision loss and sustained moderate vision loss. The study was conducted at Joslin Diabetes Center and at centres in the US, Canada, Denmark, The Netherlands and the UK. In 2004, Eli Lilly presented new analysis of previously reported data for ruboxistaurin in diabetic macular oedema indicating that ruboxistaurin has the potential to decrease the progression of diabetic macular oedema involving the center of the macula. Positive results from the PKC Beta Inhibitor Diabetic Macular Edema (PKC-DMES) trial were reported in 2003. Eli Lilly expected to file for approval of ruboxistaurin for the treatment of diabetic peripheral neuropathy in the US and Europe in 2005. However, no development was reported for this indication. On 15 March 2007, Eli Lilly withdrew its marketing authorisation application for ruboxistaurin for diabetic retinopathy filed with EMEA in May 2006. Its current development status in the EU is unclear at this stage.

Inhibition of PKC beta by ruboxistaurin does not enhance the acute blood pressure response to nitroglycerin.

Ruboxistaurin is a selective protein kinase C beta inhibitor undergoing clinical investigation for treatment of diabetic microvascular complications. This study assessed a possible blood pressure (BP) interaction between ruboxistaurin and the exogenous nitric oxide donor, glyceryl trinitrate (GTN). Subjects (N=22) with chronic stable angina received placebo or ruboxistaurin 96 mg/day orally to steady state in a crossover design. Graded GTN (0, 5, 10, 20, 40, 80, and 120 microg/min) or 5% dextrose solution was then infused intravenously and BP was measured following each dose. Ruboxistaurin did not alter the slope of change in standing systolic BP (DeltasSBP/1n[GTN dose]) curve (P=0.272 analysis of covariance) or affect the DeltasSBP at the estimated GTN dose producing a 10-mm Hg reduction in sSBP from baseline on placebo (mean difference -0.9 mm Hg; 95% confidence of interval, -3.3-1.5). In conclusion, ruboxistaurin does not potentiate the acute BP-lowering effects of GTN.

Effect of ruboxistaurin in patients with diabetic macular edema: thirty-month results of the randomized PKC-DMES clinical trial.

OBJECTIVE: To evaluate the safety and efficacy of orally administered ruboxistaurin (RBX) as a mesylate salt in patients with diabetic macular edema (DME). DESIGN: Multicenter, double-masked, randomized, placebo-controlled study of 686 patients receiving placebo or RBX orally (4, 16, or 32 mg/d) for 30 months. At baseline, patients had DME farther than 300 mum from the center of the macula, an Early Treatment Diabetic Retinopathy Study retinopathy severity level from 20 to 47A without prior photocoagulation, and an Early Treatment Diabetic Retinopathy Study visual acuity of 75 or more letters in the study eye. The primary study outcome was progression to sight-threatening DME or application of focal/grid photocoagulation for DME. Main Outcome Measure Masked grading of stereoscopic fundus photographs. RESULTS: The delay in progression to the primary outcome was not statistically significant (32 mg of RBX vs placebo, P = .14 [unadjusted]; Cox proportional hazards model adjusted for covariates, hazards ratio = 0.73; 95% confidence interval, 0.53-1.0; P = .06). However, application of focal/grid photocoagulation prior to progression to sight-threatening DME varied by site, and a secondary analysis of progression to sight-threatening DME alone showed that 32 mg of RBX per day reduced progression, compared with placebo (P = .054 [unadjusted]; Cox proportional hazards model, hazards ratio = 0.66; 95% confidence interval, 0.47-0.93; P = .02). CONCLUSIONS: Although progression to the primary outcome was not delayed, daily oral administration of RBX may delay progression of DME to a sight-threatening stage. Ruboxistaurin was well tolerated in this study.

A multicenter clinical study of the safety and activity of maleimide-polyethylene glycol-modified Hemoglobin (Hemospan) in patients undergoing major orthopedic surgery.

BACKGROUND: Hemospan (Sangart Inc., San Diego, CA), a polyethylene glycol-modified hemoglobin with unique oxygen transport properties, has successfully completed a phase I trial in healthy volunteers. Because adverse events are expected to increase with age, the authors conducted a phase II safety study of Hemospan in elderly patients undergoing elective hip arthroplasty during spinal anesthesia. METHODS: Ninety male and female patients, American Society of Anesthesiologists physical status I-III, aged 50-89 yr, in six Swedish academic hospitals were randomly assigned to receive either 250 or 500 ml Hemospan or Ringer's acetate (30 patients/group) before induction of spinal anesthesia. Safety assessment included vital signs and Holter monitoring from infusion to 24 h, evaluation of laboratory values, and fluid balance. The hypothesis to be tested was that the incidence of adverse events would be no more frequent in patients who received Hemospan compared with standard of care (Ringer's acetate). RESULTS: Three serious adverse events were noted, none of which was deemed related to study treatment. Liver enzymes, amylase, and lipase increased transiently in patients in all three groups. There were no significant differences in electrocardiogram or Holter parameters, but there was a suggestion of more bradycardic events in the treated groups. Hypotension was less frequent in the treated patients compared with controls. CONCLUSIONS: In comparison with Ringer's acetate, Hemospan mildly elevates hepatic enzymes and lipase and is associated with less hypotension and more bradycardic events. The absence of a high frequency of serious adverse events suggests that further clinical trials should be undertaken.

Clinical safety of the selective PKC-beta inhibitor, ruboxistaurin.

The aim of this manuscript is to report the safety profile of patients treated with ruboxistaurin mesylate (RBX; LY333531), a selective protein kinase C-beta (PKC-beta) inhibitor, for up to 4 years. Data from patients with diabetes (1396 RBX 32 mg/day; 1408 placebo) were combined from 11 placebo-controlled, double-masked studies. The proportion of patients who reported one or more serious adverse events was greater in the placebo group than in the RBX-treated group (23.2 versus 20.8%, respectively). There were 51 deaths (21 RBX; 30 placebo) reported in this patient cohort; none of the deaths was attributed to study drug by the investigators. Common adverse drug reactions (> or = 1/100 - < 1/10 patients) that were reported in the RBX-treated patients were dyspepsia and increased blood creatine phosphokinase. In controlled, randomised clinical trials, RBX had an adverse event profile comparable to placebo, and was well tolerated.

Effect of ruboxistaurin on visual loss in patients with diabetic retinopathy.

OBJECTIVE: To evaluate the effect of ruboxistaurin, an orally administered protein kinase C beta (PKC beta) isozyme-selective inhibitor, on vision loss in patients with diabetes. DESIGN: Thirty-six-month, randomized, double-masked, placebo-controlled, parallel, multicenter trial. PARTICIPANTS: Six hundred eighty-five patients randomized at 70 clinical sites. METHODS: Ophthalmologic examination was performed at screening and at each 3-month visit. Retinopathy status was assessed every 6 months with Early Treatment Diabetic Retinopathy Study (ETDRS) standard 7-field 30 degrees color stereoscopic fundus photography. Levels of diabetic retinopathy and diabetic macular edema were determined by 2 independent graders masked to site and treatment assignment, with additional independent adjudication as required. Eligible patients had a best-corrected visual acuity (VA) score of > or =45 letters, retinopathy level > or = 47A and < or = 53E, and no prior panretinal photocoagulation in at least one eye. MAIN OUTCOME MEASURE: Effect of oral ruboxistaurin (32 mg/day) on reduction of sustained moderate visual loss (> or =15-letter decrease in ETDRS VA score maintained > or = 6 months) in patients with moderately severe to very severe nonproliferative diabetic retinopathy. RESULTS: Sustained moderate visual loss occurred in 9.1% of placebo-treated patients versus 5.5% of ruboxistaurin-treated patients (40% risk reduction, P = 0.034). Mean VA was better in the ruboxistaurin-treated patients after 12 months. Baseline-to-end point visual improvement of > or =15 letters was more frequent (4.9% vs. 2.4%) and > or =15-letter worsening was less frequent (6.7% vs. 9.9%) in ruboxistaurin-treated patients relative to placebo (P = 0.005). When clinically significant macular edema was >100 microm from the center of the macula at baseline, ruboxistaurin treatment was associated with less frequent progression of edema to within 100 microm (68% vs. 50%, P = 0.003). Initial laser treatment for macular edema was 26% less frequent in eyes of ruboxistaurin-treated patients (P = 0.008). CONCLUSION: Oral ruboxistaurin treatment reduced vision loss, need for laser treatment, and macular edema progression, while increasing occurrence of visual improvement in patients with nonproliferative retinopathy.

Effects of chronic renal failure on the pharmacokinetics of ruboxistaurin and its active metabolite 338522.

BACKGROUND: Ruboxistaurin, a specific inhibitor of the beta(1) and beta(2) isoforms of protein kinase C, is currently in clinical development for the treatment of several diabetic microvascular complications. The major metabolite, N-desmethyl ruboxistaurin (metabolite 338522), is equipotent in its inhibitory activity. The elimination of ruboxistaurin and its metabolites is primarily through bile and the faecal route, with urinary excretion constituting only a minor route. OBJECTIVE: To assess the effects of chronic renal insufficiency on the pharmacokinetics of ruboxistaurin and metabolite 338522. METHODS: Six healthy subjects (creatinine clearance >80 mL/min/1.73 m(2)) and six end-stage renal disease (ESRD) subjects requiring long-term haemodialysis were studied. All subjects received a single oral dose of ruboxistaurin 32 mg followed by serial blood sampling up to 72 hours. ESRD subjects underwent haemodialysis approximately 58 hours after dosing, with blood samples obtained immediately before and after dialysis. RESULTS: No differences were observed in the pharmacokinetic parameters (area under the plasma concentration-time curve from time zero to infinity [AUC(infinity)], maximum plasma concentration [C(max)] and elimination half-life [t(1/2)]) of ruboxistaurin and metabolite 338522 between healthy and ESRD subjects Plasma concentrations of ruboxistaurin were below the lower limit of quantification by the time of haemodialysis. The predicted post-dialysis plasma concentrations of metabolite 338522 were not statistically different from the observed values (p=0.163). Ruboxistaurin was well tolerated in both groups of subjects. CONCLUSION: These results indicate that the kidney is not an important route of metabolism or excretion for ruboxistaurin and metabolite 338522. Based on the pharmacokinetic and tolerability findings, no formal dosage adjustment of ruboxistaurin should be required for patients with any degree of renal impairment who are undergoing haemodialysis.