Vupanorsen, an N-acetyl galactosamine-conjugated antisense drug to ANGPTL3 mRNA, lowers triglycerides and atherogenic lipoproteins in patients with diabetes, hepatic steatosis, and hypertriglyceridaemia

Aims 

Loss-of-function mutations in ANGPTL3 are associated with beneficial effects on lipid and glucose metabolism and reduced risk of coronary artery disease. Vupanorsen (AKCEA-ANGPTL3-L Rx ) is an N-acetyl galactosamine-conjugated antisense oligonucleotide targeted to the liver that selectively inhibits angiopoietin-like 3 (ANGPTL3) protein synthesis.

Methods and results 

This was a double-blind, placebo-controlled, dose-ranging, Phase 2 study. Patients (N =105) with fasting triglycerides >150 mg/dL (>1.7 mmol/L), type 2 diabetes, and hepatic steatosis were treated for 6 months with 40 or 80 mg every 4 weeks (Q4W), or 20 mg every week (QW) of vupanorsen, or placebo given subcutaneously. The primary efficacy endpoint was per cent change in fasting triglycerides from baseline at 6 months. Median baseline triglycerides were 2.84 mmol/L (252 mg/dL). Significant reductions in triglycerides of 36%, 53%, 47%, and in ANGPTL3 of 41%, 59%, 56%, were observed in the 40 mg Q4W, 80 mg Q4W, and 20 mg QW groups, respectively, compared with 16% reduction in triglycerides and 8% increase in ANGPTL3 in placebo. Compared with placebo, vupanorsen 80 mg Q4W reduced apolipoprotein C-III (58%), remnant cholesterol (38%), total cholesterol (19%), non-high-density lipoprotein cholesterol (HDL-C; 18%), HDL-C (24%), and apolipoprotein B (9%). There was no improvement in glycaemic parameters, or hepatic fat fraction. Treatment with vupanorsen was not associated with clinically significant changes in platelet counts, and the most common adverse events were those at the injection site, which were generally mild.

Conclusion 

Vupanorsen results in a favourable lipid/lipoprotein profile and provides a potential strategy for residual cardiovascular risk reduction.

Antisense-Mediated Lowering of Plasma Apolipoprotein C-III by Volanesorsen Improves Dyslipidemia and Insulin Sensitivity in Type 2 Diabetes

OBJECTIVE

To determine the effects of volanesorsen (ISIS 304801), a second-generation 2'-O-methoxyethyl chimeric antisense inhibitor of apolipoprotein (apo)C-III, on triglyceride (TG) levels and insulin resistance in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A randomized, double-blind, placebo-controlled trial was performed in 15 adult patients with type 2 diabetes (HbA1c >7.5% [58 mmol/mol]) and hypertriglyceridemia (TG >200 and <500 mg/dL). Patients were randomized 2:1 to receive volanesorsen 300 mg or placebo for a total of 15 subcutaneous weekly doses. Glucose handling and insulin sensitivity were measured before and after treatment using a two-step hyperinsulinemic-euglycemic clamp procedure.

RESULTS

Treatment with volanesorsen significantly reduced plasma apoC-III (-88%, P = 0.02) and TG (-69%, P = 0.02) levels and raised HDL cholesterol (HDL-C) (42%, P = 0.03) compared with placebo. These changes were accompanied by a 57% improvement in whole-body insulin sensitivity (P < 0.001). Importantly, we found a strong relationship between enhanced insulin sensitivity and both plasma apoC-III (r = -0.61, P = 0.03) and TG (r = -0.68, P = 0.01) suppression. Improved insulin sensitivity was sufficient to significantly lower glycated albumin (-1.7%, P = 0.034) and fructosamine (-38.7 μmol/L, P = 0.045) at the end of dosing and HbA1c (-0.44% [-4.9 mmol/mol], P = 0.025) 3 months postdosing.

CONCLUSIONS

Volanesorsen reduced plasma apoC-III and TG while raising HDL-C levels. Importantly, glucose disposal, insulin sensitivity, and integrative markers of diabetes also improved in these patients after short-term treatment.

Abstract 52: Efficacy and Safety of Mipomersen in Patients with Familial Hypercholesterolemia and Inadequately Controlled LDL-C Levels

Aim: Mipomersen is an antisense oligonucleotide inhibitor of apolipoprotein B-100 synthesis, FDA-approved to treat homozygous familial hypercholesterolemia. The primary objective of this study was to determine whether mipomersen significantly reduced atherogenic lipid levels in patients with severe heterozygous familial hypercholesterolemia (HeFH).

Methods: This was a randomized, double-blind, placebo-controlled, parallel-group study comprised of two cohorts (NCT01475825). Cohort 1 had severe HeFH (LDL-C ≥200 mg/dL + coronary heart disease, or LDL-C ≥300 mg/dL) and Cohort 2 had milder HeFH (LDL-C ≥160 and <200 mg/dL). For each cohort, patients were randomized 1:1 to 200 mg SC once weekly or 70 mg SC thrice weekly, then 2:1 to receive mipomersen or placebo for 60 weeks. The primary outcome was percent change from baseline in LDL-C in Cohort 1. The % change from baseline in LDL-C at Week 61 for mipomersen treated patients was compared to placebo using a mixed model for repeated measures (MMRM), as well as by ANCOVA on the value closest to 7 days post last treatment (LOCF).

Results: Mean baseline LDL-C levels were 265 mg/dL in Cohort 1 (N=200) and 176 mg/dL in Cohort 2 (N=109). In Cohort 1, mipomersen 200 mg weekly reduced LDL-C levels by -29.7% (vs -7.9% placebo, P <.001) in the mixed model, and by -36.3% (vs -7.6% placebo, P <.001) using the LOCF. Analysis of LDL-C over time (Figure) showed a mean absolute reduction of 138 mg/dL in mipomersen patients who completed the blinded treatment period (n=32), achieving a mean level of 147 mg/dL from a mean 285 mg/dL baseline level. Tolerability to treatment and adverse events were similar between dose regimens. Adverse events were consistent with the drug’s known safety and tolerability profile.

Conclusions: The primary analysis showed a significant reduction in LDL-C levels in patients with severe HeFH who received mipomersen 200 mg once weekly versus placebo. A highly relevant absolute reduction in LDL-C was achieved over time.

No effect on QT intervals of mipomersen, a 2'-O-methoxyethyl modified antisense oligonucleotide targeting ApoB-100 mRNA, in a phase I dose escalation placebo-controlled study, and confirmed by a thorough QT (tQT) study, in healthy subjects

PURPOSE

The aim of this study to evaluate the effect of mipomersen on QT intervals in a phase I dose escalation, placebo-controlled study, and a thorough QT (tQT) study in healthy subjects.

METHODS

In the initial phase I study, 29 healthy subjects received either single or multiple (for 4 weeks) ascending doses of mipomersen (50-400 mg) administered subcutaneously (SC) or via a 2-h intravenous (IV) infusion, and 7 subjects received placebo. In the confirmative tQT study, 58 healthy subjects received placebo, 400 mg IV moxifloxacin, 200 mg SC, or 200 mg IV of mipomersen in a double-blind, 4-way crossover design with a minimum 5-day washout between treatments. ECG measurements were performed at baseline and selected time points (including Tmax). The correlation between QTcF intervals corrected for baseline and time-matched placebo when available with PK plasma exposure was evaluated by linear regression analysis.

RESULTS

In the phase I study, no positive correlation between the PK exposure and ∆QTcF or ∆∆QTcF was observed within the wide dose or exposure range tested. Similar results were observed in the tQT study, where the predicted ΔΔQTcF and its upper bound of the 90% CI at Cmax of therapeutic and supratherapeutic dose were approximately -1.7 and 2.9 ms, respectively.

CONCLUSIONS

Mipomersen showed no effect on QT intervals in both the phase I dose escalation study and the tQT study. These results support the proposal that QT assessment can be made in a phase I dose escalation study, and no tQT study may be necessary if the phase I dose escalation study showed a negative QT effect.

Antisense therapy targeting apolipoprotein(a): a randomised, double-blind, placebo-controlled phase 1 study

BACKGROUND

Lipoprotein(a) (Lp[a]) is a risk factor for cardiovascular disease and calcific aortic valve stenosis. No effective therapies to lower plasma Lp(a) concentrations exist. We have assessed the safety, pharmacokinetics, and pharmacodynamics of ISIS-APO(a)Rx, a second-generation antisense drug designed to reduce the synthesis of apolipoprotein(a) (apo[a]) in the liver.

METHODS

In this randomised, double-blind, placebo-controlled, phase 1 study at the PAREXEL Clinical Pharmacology Research Unit (Harrow, Middlesex, UK), we screened for healthy adults aged 18-65 years, with a body-mass index less than 32·0 kg/m(2), and Lp(a) concentration of 25 nmol/L (100 mg/L) or more. Via a randomisation technique, we randomly assigned participants to receive a single subcutaneous injection of ISIS-APO(a)Rx (50 mg, 100 mg, 200 mg, or 400 mg) or placebo (3:1) in the single-dose part of the study or to receive six subcutaneous injections of ISIS-APO(a)Rx (100 mg, 200 mg, or 300 mg, for a total dose exposure of 600 mg, 1200 mg, or 1800 mg) or placebo (4:1) during a 4 week period in the multi-dose part of the study. Participants, investigators, and study staff were masked to the treatment assignment, except for the pharmacist who prepared the ISIS-APO(a)Rx or placebo. The primary efficacy endpoint was the percentage change from baseline in Lp(a) concentration at 30 days in the single-dose cohorts and at 36 days for the multi-dose cohorts. Safety and tolerability was assessed 1 week after last dose and included determination of the incidence, severity, and dose relation of adverse events and changes in laboratory variables, including lipid panel, routine haematology, blood chemistry, urinalysis, coagulation, and complement variables. Other assessments included vital signs, a physical examination, and 12-lead electrocardiograph. This trial is registered with European Clinical Trials Database, number 2012-004909-27.

FINDINGS

Between Feb 27, 2013, and July 15, 2013, 47 (23%) of 206 screened volunteers were randomly assigned to receive ISIS-APO(a)Rx as a single-dose or multi-dose of ascending concentrations or placebo. In the single-dose study, we assigned three participants to receive 50 mg ISIS-APO(a)Rx, three participants to receive 100 mg ISIS-APO(a)Rx, three participants to receive 200 mg ISIS-APO(a)Rx, three participants to receive 400 mg ISIS-APO(a)Rx, and four participants to receive placebo. All 16 participants completed treatment and follow-up and were included in the pharmacodynamics, pharmacokinetics, and safety analyses. For the multi-dose study, we assigned eight participants to receive six doses of 100 mg ISIS-APO(a)Rx, nine participants to receive six doses of 200 mg ISIS-APO(a)Rx, eight participants to receive six doses of 300 mg ISIS-APO(a)Rx, and six participants to receive six doses of placebo. Whereas single doses of ISIS-APO(a)Rx (50-400 mg) did not decrease Lp(a) concentrations at day 30, six doses of ISIS-APO(a)Rx (100-300 mg) resulted in dose-dependent, mean percentage decreases in plasma Lp(a) concentration of 39·6% from baseline in the 100 mg group (p=0·005), 59·0% in the 200 mg group (p=0·001), and 77·8% in the 300 mg group (p=0·001). Similar reductions were observed in the amount of oxidized phospholipids associated with apolipoprotein B-100 and apolipoprotein(a). Mild injection site reactions were the most common adverse events.

INTERPRETATION

ISIS-APO(a)Rx results in potent, dose-dependent, selective reductions of plasma Lp(a). The safety and tolerability support continued clinical development of ISIS-APO(a)Rx as a potential therapeutic drug to reduce the risk of cardiovascular disease and calcific aortic valve stenosis in patients with elevated Lp(a) concentration.

FUNDING

Isis Pharmaceuticals.

Antisense Inhibition of Apolipoprotein C-III in Patients with Hypertriglyceridemia

BACKGROUND

Apolipoprotein C-III (APOC3) is a key regulator of plasma triglyceride levels. Elevated triglyceride levels are associated with a risk of adverse cardiovascular events and pancreatitis. ISIS 304801 is a second-generation antisense inhibitor of APOC3 synthesis.

METHODS

We conducted a randomized, double-blind, placebo-controlled, dose-ranging, phase 2 study to evaluate ISIS 304801 in untreated patients with fasting triglyceride levels between 350 mg per deciliter (4.0 mmol per liter) and 2000 mg per deciliter (22.6 mmol per liter) (ISIS 304801 monotherapy cohort), as well as in patients receiving stable fibrate therapy who had fasting triglyceride levels between 225 mg per deciliter (2.5 mmol per liter) and 2000 mg per deciliter (ISIS 304801-fibrate cohort). Eligible patients were randomly assigned to receive either ISIS 304801, at doses ranging from 100 to 300 mg, or placebo, once weekly for 13 weeks. The primary outcome was the percentage change in APOC3 level from baseline.

RESULTS

A total of 57 patients were treated in the ISIS 304801 monotherapy cohort (41 received active agent, and 16 received placebo), and 28 patients were treated in the ISIS 304801-fibrate cohort (20 received active agent, and 8 received placebo). The mean (±SD) baseline triglyceride levels in the two cohorts were 581±291 mg per deciliter (6.6±3.3 mmol per liter) and 376±188 mg per deciliter (4.2±2.1 mmol per liter), respectively. Treatment with ISIS 304801 resulted in dose-dependent and prolonged decreases in plasma APOC3 levels when the drug was administered as a single agent (decreases of 40.0±32.0% in the 100-mg group, 63.8±22.3% in the 200-mg group, and 79.6±9.3% in the 300-mg group, vs. an increase of 4.2±41.7% in the placebo group) and when it was administered as an add-on to fibrates (decreases of 60.2±12.5% in the 200-mg group and 70.9±13.0% in the 300-mg group, vs. a decrease of 2.2±25.2% in the placebo group). Concordant reductions of 31.3 to 70.9% were observed in triglyceride levels. No safety concerns were identified in this short-term study.

CONCLUSIONS

We found that treatment with ISIS 304801 was associated with significant lowering of triglyceride levels, among patients with a broad range of baseline levels, through selective antisense inhibition of APOC3 synthesis. (Funded by Isis Pharmaceuticals; ClinicalTrials.gov number, NCT01529424.).

Results of a proof of concept, double-blind, randomized trial of a second generation antisense oligonucleotide targeting high-sensitivity C-reactive protein (hs-CRP) in rheumatoid arthritis

Introduction

This randomized, double-blind, phase II study evaluated the pharmacodynamics, safety and tolerability of ISIS 329993 (ISIS-CRP_Rx), an antisense oligonucleotide, in patients with active rheumatoid arthritis (RA).

Methods

Patients with active RA of at least six months duration were randomized into three cohorts to receive ISIS-CRP_Rx (100 mg, 200 mg or 400 mg) or placebo (3 active:1 placebo within each cohort) via subcutaneous (SC) injection on Days 1, 3, 5 and 8 and then once weekly for the next 11 weeks. The effects of study treatment on high-sensitivity C-reactive protein (hs-CRP) level were evaluated. An exploratory analysis on disease activity was assessed via the American College of Rheumatology 20% improvement criteria (ACR20). Safety was evaluated via adverse events and laboratory measures.

Results

Fifty-one patients received one of the following treatments: ISIS-CRP_Rx 100 mg, n = 12; 200 mg, n = 13, 400 mg, n = 14; placebo n = 12. In the ISIS-CRP_Rx treatment groups there were dose-dependent reductions in hs-CRP. At Day 36 the mean percent change from baseline was: placebo: −14.4%; ISIS-CRP_Rx 100 mg: −19.5%; 200 mg: −56.6% and 400 mg: −76.7%, (P = 0.0015 placebo compared to 400 mg). There were no differences between treatment groups and placebo in the ACR20 at Day 36 or Day 92. There were no serious infections and no elevations in liver function tests, lipids, creatinine or other lab abnormalities related to ISIS-CRP_Rx.

Conclusions

In this study, ISIS-CRP_Rx selectively reduced hs-CRP in a dose-dependent manner, and was well-tolerated in patients with RA. Its utility as a therapy in RA remains unclear.

Trial registration

Clinicaltrials.gov NCT01414101. Registered 21 July 2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0578-5) contains supplementary material, which is available to authorized users.

Targeting APOC3 in the familial chylomicronemia syndrome

The familial chylomicronemia syndrome is a genetic disorder characterized by severe hypertriglyceridemia and recurrent pancreatitis due to a deficiency in lipoprotein lipase (LPL). Currently, there are no effective therapies except for extreme restriction in the consumption of dietary fat. Apolipoprotein C-III (APOC3) is known to inhibit LPL, although there is also evidence that APOC3 increases the level of plasma triglycerides through an LPL-independent mechanism. We administered an inhibitor of APOC3 messenger RNA (mRNA), called ISIS 304801, to treat three patients with the familial chylomicronemia syndrome and triglyceride levels ranging from 1406 to 2083 mg per deciliter (15.9 to 23.5 mmol per liter). After 13 weeks of study-drug administration, plasma APOC3 levels were reduced by 71 to 90% and triglyceride levels by 56 to 86%. During the study, all patients had a triglyceride level of less than 500 mg per deciliter (5.7 mmol per liter) with treatment. These data support the role of APOC3 as a key regulator of LPL-independent pathways of triglyceride metabolism.

Antisense oligonucleotide inhibition of apolipoprotein C-III reduces plasma triglycerides in rodents, nonhuman primates, and humans

RATIONALE

Elevated plasma triglyceride levels have been recognized as a risk factor for the development of coronary heart disease. Apolipoprotein C-III (apoC-III) represents both an independent risk factor and a key regulatory factor of plasma triglyceride concentrations. Furthermore, elevated apoC-III levels have been associated with metabolic syndrome and type 2 diabetes mellitus. To date, no selective apoC-III therapeutic agent has been evaluated in the clinic.

OBJECTIVE

To test the hypothesis that selective inhibition of apoC-III with antisense drugs in preclinical models and in healthy volunteers would reduce plasma apoC-III and triglyceride levels.

METHODS AND RESULTS

Rodent- and human-specific second-generation antisense oligonucleotides were identified and evaluated in preclinical models, including rats, mice, human apoC-III transgenic mice, and nonhuman primates. We demonstrated the selective reduction of both apoC-III and triglyceride in all preclinical pharmacological evaluations. We also showed that inhibition of apoC-III was well tolerated and not associated with increased liver triglyceride deposition or hepatotoxicity. A double-blind, placebo-controlled, phase I clinical study was performed in healthy subjects. Administration of the human apoC-III antisense drug resulted in dose-dependent reductions in plasma apoC-III, concomitant lowering of triglyceride levels, and produced no clinically meaningful signals in the safety evaluations.

CONCLUSIONS

Antisense inhibition of apoC-III in preclinical models and in a phase I clinical trial with healthy subjects produced potent, selective reductions in plasma apoC-III and triglyceride, 2 known risk factors for cardiovascular disease. This compelling pharmacological profile supports further clinical investigations in hypertriglyceridemic subjects.

A Selective Inhibitor of Human C-reactive Protein Translation Is Efficacious In Vitro and in C-reactive Protein Transgenic Mice and Humans

Observational studies of patients with established rheumatoid arthritis (RA) document a positive correlation between C-reactive protein (CRP) blood concentration and worsening of RA symptoms, but whether this association is causal or not is not known. Using CRP transgenic mice (CRPTg) with collagen-induced arthritis (CIA; a rodent model of RA), we explored causality by testing if CRP lowering via treatment with antisense oligonucleotides (ASOs) targeting human CRP mRNA was efficacious and of clinical benefit. We found that in CRPtg with established CIA, ASO-mediated lowering of blood human CRP levels improved the clinical signs of arthritis. In addition, in healthy human volunteers the ASO was well tolerated and efficacious i.e., treatment achieved significant CRP lowering. ASOs targeting CRP should provide a specific and effective way to lower human CRP levels, which might be an effective therapy in patients with established RA.

Transcranial ultrasound in clinical sonothrombolysis (TUCSON) trial

OBJECTIVE

Microspheres (microS) reach intracranial occlusions and transmit energy momentum from an ultrasound wave to residual flow to promote recanalization. We report a randomized multicenter phase II trial of microS dose escalation with systemic thrombolysis.

METHODS

Stroke patients receiving 0.9mg/kg tissue plasminogen activator (tPA) with pretreatment proximal intracranial occlusions on transcranial Doppler (TCD) were randomized (2:1 ratio) to microS (MRX-801) infusion over 90 minutes (Cohort 1, 1.4ml; Cohort 2, 2.8ml) with continuous TCD insonation, whereas controls received tPA and brief TCD assessments. The primary endpoint was symptomatic intracerebral hemorrhage (sICH) within 36 hours after tPA.

RESULTS

Among 35 patients (Cohort 1 = 12, Cohort 2 = 11, controls = 12) no sICH occurred in Cohort 1 and controls, whereas 3 (27%, 2 fatal) sICHs occurred in Cohort 2 (p = 0.028). Sustained complete recanalization/clinical recovery rates (end of TCD monitoring/3 month) were 67%/75% for Cohort 1, 46%/50% for Cohort 2, and 33%/36% for controls (p = 0.255/0.167). The median time to any recanalization tended to be shorter in Cohort 1 (30 min; interquartile range [IQR], 6) and Cohort 2 (30 min; IQR, 69) compared to controls (60 min; IQR, 5; p = 0.054). Although patients with sICH had similar screening and pretreatment systolic blood pressure (SBP) levels in comparison to the rest, higher SBP levels were documented in sICH+ patients at 30 minutes, 60 minutes, 90 minutes, and 24-36 hours following tPA bolus.

INTERPRETATION

Perflutren lipid microS can be safely combined with systemic tPA and ultrasound at a dose of 1.4ml. Safety concerns in the second dose tier may necessitate extended enrollment and further experiments to determine the mechanisms by which microspheres interact with tissues. In both dose tiers, sonothrombolysis with microS and tPA shows a trend toward higher early recanalization and clinical recovery rates compared to standard intravenous tPA therapy. Ann Neurol 2009;66:28-38.

Frontoethmoidal meningoencephalocoele repair in Cambodia: outcomes and cost comparisons

In Cambodia, spina bifida is rare, but frontoethmoidal meningoencephalocoeles (MECs) are common. Mean life expectancy for patients with congenital MECs may be <20 years, but the complex treatment required has not been available in the country until recently. During visits by combined neurosurgical/craniofacial teams from both Germany and France, a method of repair has been developed that is suitable for the local conditions, affordable and has allowed Cambodian surgeons to learn how to successfully treat MECs. The surgical technique and initial results with 30 patients have been described in a previous publication. This paper presents the outcomes of 128 cases and illustrates that it is cost-effective for these patients to be treated in Cambodia.

Characterization and differential nuclear localization of Nopp140 and a novel Nopp140-like protein in trypanosomes

Trypanosomatids possess two homologues of Nopp140: a canonical Nopp140 and a Nopp140-like protein (TbNoLP) in which a GAR domain replaces the C-terminal SRP40 domain. Both are phosphorylated and coimmunoprecipitate with RNA polymerase I. Each paralogue has a distinct subnuclear localization, and depletion of TbNoLP produces an enlarged nucleolus in which TbNopp140-containing regions disperse. The restricted occurrence pattern of NoLP proteins reflects an intriguing convergence in evolution, suggestive of a function in nucleoplasmic small nucleolar ribonucleoprotein shuttling.

A spontaneously arising porcine model of bullous pemphigoid

Bullous pemphigoid (BP) is an IgG-mediated autoimmune blistering disease targeting the hemidesmosomal proteins bullous pemphigoid antigens 1 and 2. Currently, there is no active animal model in which to dissect the immunopathogenic mechanism. We noticed that cutaneous blistering arose spontaneously in 12 adult Yucatan minipigs. Skin lesions consisted of turgid, isolated or clustered vesicles that occasionally evolved from erythematous and pruritic patches. Histopathological examination revealed subepidermal vesicles rich in intact and degranulated eosinophils. Antigen mapping and transmission electron microscopy confirmed that dermoepidermal separation took place in the lamina lucida of the epidermal basement membrane zone. Direct immunofluorescence revealed the presence of IgG deposited linearly at the dermoepidermal junction in seven of nine skin specimens examined. Indirect immunofluorescence testing confirmed the presence, in the serum from eight of eight affected pigs, of circulating basement membrane-specific IgG autoantibodies (titers 1 : 50 to 1 : 250). Using uncleaved and salt-split lip substrates, the autoantibodies were shown to target antigens situated not only at the basal, but also at the lateral and apical aspects of stratum basale keratinocytes. Immunoelectron microscopy confirmed that circulating IgG autoantibodies recognized hemidesmosomal antigen(s). ELISA, immunoblotting and immunoadsorption demonstrated that five of eight serum samples exhibited high immunoreactivity against BPAG2-NC16A peptides. This novel porcine acquired blistering dermatosis could be proposed as a valuable model to conduct immunomechanistic studies on the natural progression of BP, correlation of autoreactive T cells or autoantibodies with disease activity, and the role of eosinophils in the blistering process, as these diseases cannot be modeled easily in human patients or in murine passive transfer models.

Efficacy and safety of Minipress XL, a new once-a-day formulation of prazosin

The efficacy and safety of prazosin GITS (gastro-intestinal therapeutic system), a new extended-release once-a-day formulation, were assessed both as monotherapy in mild essential hypertension and in combination with a diuretic in moderate essential hypertension in two multicenter, double-blind, placebo-controlled trials. Prazosin GITS (Minipress XL) given once daily in doses of either 10 or 20 mg significantly reduced sitting and standing systolic and diastolic blood pressure compared with placebo in both mild and moderate essential hypertension. There were minimal, clinically insignificant changes in heart rate following prazosin-GITS treatment (2.5, 10, and 20 mg) compared with placebo treatment. Prazosin GITS was well tolerated; the most common adverse experiences reported were headache, dizziness, and fatigue. All adverse experiences in the moderate hypertension group and the majority (91 percent) in the mild hypertension group were mild-to-moderate in severity. The results from these multicenter trials demonstrate the efficacy and safety of this new extended-release once-a-day formulation of prazosin in the treatment of patients with mild and moderate essential hypertension.

Clinical pharmacokinetics of nifedipine gastrointestinal therapeutic system. A controlled-release formulation of nifedipine

The pharmacokinetics of nifedipine following intravenous administration can be represented by an open two-compartment model with a terminal elimination half-life of about two hours. Nifedipine is extensively biotransformed to inactive metabolites, and the total body clearance (450 to 700 ml/minute) is primarily due to hepatic metabolism. Nifedipine undergoes significant tissue distribution in that the steady-state volume of distribution (0.62 to 0.77 liter/kg) is more than twice the volume of distribution of the central compartment (0.25 to 0.29 liter/kg). Although nifedipine is almost completely absorbed from the gastrointestinal tract, oral bioavailability ranges from 45 to 68 percent because of first-pass metabolism. Nifedipine given three times daily shows no accumulation in plasma and no changes in pharmacokinetic behavior during a one-week study period. Pharmacokinetic studies on the gastrointestinal therapeutic system (GITS) show that the bioavailability of the GITS dosage form (relative to the capsule) is about 65 percent after a single dose, but increases to about 86 percent at steady-state because of residual absorption more than 24 hours after dosing. Linear pharmacokinetics are seen following administration of single oral doses of nifedipine GITS as indicated by dose-proportional increases in the area under the plasma drug concentration-time curve over the range of 30 to 180 mg. Administration of the GITS dosage form in the presence of food slightly increases the rate of drug absorption, but does not influence the extent of drug bioavailability. Dose-dumping has not been observed, even with dosing after a meal containing a high level of fat. The GITS tablets provide zero-order delivery of nifedipine, and drug absorption persists beyond the dosing interval of 24 hours. Thus, the GITS dosage form will permit once-a-day dosing and maintain the desired, constant plasma drug concentration with minimal fluctuation.

Application of a novel cation-exchange reagent, Igepon T-77 (N-methyl oleoyl taurate), to microbore separations of alumina extracts of catecholamines from cerebrospinal fluid, plasma, urine and brain tissue with amperometric detection

The use of a novel amide surfactant, N-methyl oleoyl taurate (Igepon T-77), has been examined for the separation of amines on reversed-phase chromatographic material. This reagent was found to partition onto the C18 material in a partially irreversible and concentration independent manner. When the stationary phase is saturated with this surfactant, the loaded column performs as a strong cation exchanger. Novel separations are possible as a result of secondary hydrogen-bonding effects which modify classical retention order for primary, secondary and tertiary amines. Sensitive and selective applications of these separations are demonstrated for catecholamine determinations in blood plasma, cerebrospinal fluid, urine and brain tissue. Additional sensitivity is obtained for epinephrine by taking advantage of the pH-dependent intramolecular cyclization and on-column concentration of large injection volumes.

The antihypertensive effects of doxazosin: a clinical overview

Doxazosin is a long-acting selective alpha 1-adrenoceptor antagonist which has been shown to be effective and well tolerated in the treatment of hypertension given in once-daily doses as monotherapy for up to 1 year or as an adjunct to thiazide or beta-adrenoceptor blockers. Doxazosin has a pharmacokinetic profile in both young adult and elderly subjects which is compatible with once-daily administration. This has been confirmed by measurement of steady state pharmacokinetics in patients receiving long-term doxazosin therapy. In controlled double-blind studies involving approximately 550 patients on doxazosin 1-16 mg once daily, significant reductions in both standing and supine BP were maintained throughout the 24 h dosing interval. Effectiveness of doxazosin in terms of BP lowering and proportion of responders was similar to that achieved with hydrochlorothiazide 25-100 mg once daily, atenolol 50-100 mg once daily, nadolol 40-160 mg once daily, metoprolol 100-200 mg per day given twice daily, or prazosin 1-20 mg per day given twice daily. Doxazosin was as effective in elderly patients as in the younger age group and was as effective in blacks as in caucasians. Doxazosin was well tolerated. Side-effects were generally mild to moderate in severity. Overall incidence, including postural effects early in treatment, was similar to that seen with the comparative agents. In comparison with placebo, doxazosin favourably increased (P less than 0.05) the HDL/total cholesterol ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Profile of trimazosin: an effective and safe antihypertensive agent

Trimazosin, a selective alpha-1-adrenoceptor-blocking agent, has been extensively evaluated in over 1000 patients. In hypertensive patients, reduction in elevated blood pressure in both supine and standing positions, consequent to a reduction in systemic vascular resistance, persisted in long-term therapy. Progression of hypertension target organ damage did not occur. Improvement in blood lipids with decreased total serum cholesterol was noted in long-term therapy. In long-term studies, 74% of patients responded at a trimazosin dose of 300 mg/day or less; the maximum dose was 300 mg/day or less in 52% of patients and 200 mg/day or less in 36%. Most patients received twice a day therapy. The side effect profile of trimazosin was comparable to placebo and significantly better than that of either methyldopa or propranolol. Concomitant disease or therapy did not adversely affect the trimazosin safety profile. Hematology, clinical chemistry, and urinary parameters did not indicate deleterious effects. Because of its excellent safety and toleration profile, trimazosin may be particularly suitable in first-line therapy of patients with mild or moderate hypertension.

Effect of trimazosin on serum lipid profiles in hypertensive patients

Abnormalities in the serum lipid profile correlate strongly with the presence and severity of atherosclerosis. Increases in serum lipids and a reduction in high-density lipoprotein (HDL) cholesterol have been demonstrated following treatment with some beta blockers and diuretics, either alone or in combination. A new alpha-1-adrenoceptor antagonist, trimazosin, was studied to determine its effects on serum lipids. Ninety-six hypertensive patients were randomly assigned in double-blind fashion to trimazosin or placebo for 8 weeks. Trimazosin was associated with a significant reduction (p less than or equal to 0.01) in total cholesterol when compared with the placebo group. This effect was seen in all patients regardless of whether or not they were taking a diuretic concomitantly. In addition, a 9-month, double-blind parallel comparison was made of trimazosin and propranolol. Trimazosin was found to be superior to propranolol in its effect on HDL cholesterol and the HDL/total cholesterol ratio. These studies have demonstrated that, in contrast to placebo and propranolol, trimazosin lowers total serum cholesterol without undesirable effects on other serum lipid fractions. When polythiazide is given concomitantly, it diminishes the favorable effects of trimazosin and accentuates the opposite, adverse effects of propranolol.

Observations on the mechanism underlying the differences in exercise and isoprenaline tachycardia after cardioselective and non-selective beta-adrenoceptor antagonists

1 Differences in ability to attenuate isoprenaline tachycardia between the cardioselective beta-adrenoceptor antagonist atenolol and the non-selective drug propranolol, when administered in equivalent anti-exercise tachycardia oral doses, were measured in four normal volunteers. 2 Propranolol at all dose comparisons showed a greater potency in antagonism of isoprenaline tachycardia than atenolol; this ranged from 6 at the lowest doses (40 and 50 mg respectively) to 13 at the highest doses (320 and 400 mg respectively). 3 After doses of each drug which produced equal inhibition of exercise tachycardia, isoprenaline induced a greater increase in heart rate and greater decrease in diastolic blood pressure after pre-treatment with atenolol than after propranolol. 4 The contribution of this isoprenaline induced vasodilatation to the reduced tachycardia response, 1 h after 25 mg oral atenolol, was measured in the same four subjects by correction of the hypotension with an intravenous angiotensin infusion. Reversal by angiotensin of the 17 mm Hg average fall in diastolic blood pressure during the sustained isoprenaline infusion did not reduce the tachycardia. 5 The hypotension that results from isoprenaline stimulation of unblocked vasodilator beta 2-adrenoceptors in normal subjects pre-treated with atenolol appears to make a negligible contribution to the tachycardia response and does not explain the different abilities of cardioselective and non-selective beta-adrenoceptor blocking drugs to antagonise isoprenaline tachycardia. Our results are compatible with the presence of beta 2-adrenoceptors in human atria.

Postjunctional selectivity of alpha-blockade with prazosin, trimazosin, and UK-33,274 in man

The effects of 3 quinazoline alpha-adrenoreceptor antagonists, prazosin, trimazosin, and UK-33,274, on lying blood pressure (BP), BP response to 60 degrees tilt, pressor response to noradrenaline, phenylephrine, and exercise (isometric and dynamic) were measured in a double-blind study in 6 volunteers. There was no difference between the effects of prazosin 2 mg, trimazosin 200 mg, and UK-33,274 4 mg on lying and tilted BP or on BP response to exercise. All three drugs competitively antagonised the systolic and diastolic pressor effect of phenylephrine and the systolic pressor effect of noradrenaline. Prazosin and UK 33,274 completely suppressed the diastolic pressor effect of noradrenaline and produced an increase rather than a decrease in heart rate (HR). Trimazosin produced a parallel shift in noradrenaline dose response curves for diastolic pressure ahd HR. Prazosin and UK-33,274, but not trimazosin, therefore, produced effects unlike those previously described with alpha-blockers, e.g., phentolamine. The difference between antagonism of the systolic and diastolic effects suggests that the resistance component of the noradrenaline pressor effect, mediated principally via alpha 1-stimulation, is more effectively blocked than the cardiac component, which depends on venous return and alpha 2-mediated venoconstriction. Prazosin and UK-33,274 are clearly alpha 1-selective. Trimazosin is less selective.

Behavioural and subjective effects of beta-adrenergic blockade in phobic subjects

It has been suggested that reversal of stress-induced tachycardia by beta-adrenergic blockade might be of benefit in the treatment of phobias. This was tested in a double-blind cross-over trial by exposing 22 female volunteers with spider or snake phobias to their phobic object 1 1/2 hours after administration of either tolamolol 200 mg, diazepam 10 mg or placebo. Although tolamolol abolished the stress-induced tachycardia, it had no beneficial behavioural or subjective effects. In contrast, diazepam, which had no significant effect on heart rate, improved behavioural performance. Subjective measures were more influenced by order effect than by medication.

Comparison of five beta-adrenoreceptor antagonists with different ancillary properties during sustained twice daily therapy in angina pectoris

The effects of five beta-adrenoreceptor blocking agents and placebo during twice daily sustained therapy were compared in 23 patients with stable, exertional angina pectoris. The study was double blind in design, and each drug was prescribed for a period of one month in a random fashion. The number of anginal attacks and consumption of glyceryl trinitrate tablets during the one month period were significantly reduced by a similar degree during therapy with all five beta blocking drugs in comparison to the placebo (P less than 0.01). Exercise tolerance, when assessed 12 hours after a previous dose had been given and 1 hour after the morning dose was given, also improved by a similar degree with all five drugs in comparison to the placebo (P less than 0.01). The increase in exercise duration was associated with a significant reduction in the S-T segment depression, heart rate, systolic blood pressure, and the product of heart rate and systolic blood pressure, with each of the five drugs--effects markedly different from those obtained with the placebo (P less than 0.01). These data show that noncardioselective (propranolol and oxprenolol) and cardioselective (practolol, metoprolol and tolamolol) agents, as well as drugs with intrinsic sympathomimetic activity (oxprenolol and practolol), were equally effective antianginal agents during sustained therapy. Furthermore, twice daily therapy with any of these drugs was effective in the management of patients with angina pectoris.

Comparison of the immediate effects of five beta-adrenoreceptor-blocking drugs with different ancillary properties in angina pectoris

We compared the immediate effects of five beta-adrenoreceptor-blocking agents in 16 patients with stable angina pectoris. Acute dose-response studies showed that all five drugs improved exercise tolerance and reduced ST-segment depression, heart rate and blood pressure by a similar degree in comparison with a placebo (P less than 0.01). Near maximum improvement in exercise tolerance occurred when the acute cumulative oral dose had reached 160 mg for propranolol and oxprenolol, 200 mg for metoprolol and tolamolol and 400 mg for practolol. When these drugs were administered as a single doses, increase in walking time before the development of angina and reduction in ST-segment depression, heart rate and systolic blood pressure all occurred within one hour and persisted for eight hours--effects markedly different from the response to a placebo (P less than 0.01). These data show that non-cardioselective agents (propranolol and oxprenolol), cardioselective agents (practolol, metoprolol and tolamolol), as well as drugs with intrinsic sympathomimetic activity (oxprenolol and practolol), were equally effective in the treatment of angina pectoris.

Comparative anti-hypertensive effectiveness of beta-adrenoreceptor antagonists with different pharmacological properties: dose-response studies during acute and chronic administration

1. Immediate and long-term blood pressure-lowering activity of five beta-adrenoreceptor antagonists with different ancillary pharmacological properties were compared in a randomized double-blind placebo controlled factorial trial in twenty-five previously untreated patients with stable uncomplicated essential hypertension. 2. In doses which produced similar reductions in exercise tachycardia, all drugs exerted similar anti-hypertensive activity, which was greater on systolic than diastolic pressure and greatest during exercise. 3. These effects were maximum within an hour and lasted for over 8 h after a single oral dose. 4. Blood pressure-lowering activity, particularly the reduction in exercise systolic pressure, was significantly related to the logarithm of the dose of each drug. 5. Anti-hypertensive activity was maximally enhanced after 4 weeks of sustained treatment at any given dose. There was no short-term habituation to treatment and substitution with placebo resulted in a return of the blood pressure to pretreatment values within 4 weeks without subsequent overshoot. 6. The blood pressure-lowering activity of these drugs was predominantly related to their common property of competitive antagonism of cardiac beta-adrenoreceptors; their ancillary pharmacological properties, with the exception of intrinsic vasodilator activity, played little part in this response.

Comparison of antihypertensive activity of beta-blocking drugs during chronic treatment

The hypotensive activity of five beta-adrenoceptor antagonists with different ancillary pharmacological properties was compared in a randomised double-blind factorial trial in 25 untreated patients with stable, uncomplicated essential hypertension. In doses that produced similar reductions in exercise tachycardia all drugs had similar blood-pressure lowering activity, greater on systolic than diastolic pressure and greatest during exercise. With the exception of vasodilator activity the possession of any particular combinaton of ancillary pharmacological properties did not significantly influence the specific antihypertensive activity of these compounds.

Bioavailability of tolamolol

Bioavailability of capsule and tablet formulations of tolamolol were compared by measuring plasma concentration of tolamolol and reduction in maximum exercise heart rate over a period of twelve hours in eight healthy subjects in a two-way cross-over study. Tolamolol was absorbed more rapidly from capsules than from tablets; this did not result in any significant difference in the reduction in maximum exercise heart rate between the two formulations. There was no significant difference between area under curve of reduction in exercise tachycardia and area under-curve of plasma concentration of tolamolol for the two formulations. Reduction in maximum exercise heart rate was related to logarithm of plasma concentration of tolamolol between two and twelve hours after both formulations.