Urodynamics and safety of the ß3-adrenoceptor agonist mirabegron in males with lower urinary tract symptoms and bladder outlet obstruction.

PURPOSE: Bladder outlet obstruction often presents as storage and voiding symptoms. We investigated urodynamic parameters in men with lower urinary tract symptoms and bladder outlet obstruction treated with the ß3 agonist mirabegron, a new therapy for overactive bladder symptoms. MATERIALS AND METHODS: A total of 200 men 45 years old or older with lower urinary tract symptoms and bladder outlet obstruction were randomized to receive once daily mirabegron 50 mg (70) or 100 mg (65), or placebo (65) for 12 weeks. The primary urodynamic parameters assessed were change from baseline to end of treatment in maximum urinary flow and detrusor pressure at maximum urinary flow (noninferiority margins -3 ml per second and 15 cm H2O, respectively). We evaluated adverse events and vital signs. RESULTS: Treatment with mirabegron 50 and 100 mg was noninferior to placebo based on the lower and upper limits of the 95% CI, respectively, for maximum urinary flow and detrusor pressure at maximum urinary flow. The adjusted mean difference vs placebo was 0.40 (95% CI -0.63, 1.42) and 0.62 ml per second (95% CI -0.43, 1.68) for maximum urinary flow, and -5.94 (95% CI -13.98, 2.09) and -1.39 cm H2O (95% CI -9.73, 6.96), respectively, for detrusor pressure at maximum urinary flow. The incidence of adverse events was similar for mirabegron and placebo. CONCLUSIONS: Mirabegron did not adversely affect voiding urodynamics (maximum urinary flow and detrusor pressure at maximum urinary flow) compared with placebo after 12 weeks of treatment.

Efficacy of mirabegron in patients with and without prior antimuscarinic therapy for overactive bladder: a post hoc analysis of a randomized European-Australian Phase 3 trial.

BACKGROUND: Antimuscarinic agents are currently the predominant treatment option for the clinical management of the symptoms of overactive bladder (OAB). However, low rates of persistence with these agents highlight the need for novel, effective and better-tolerated oral pharmacological agents. Mirabegron is a ß3-adrenoceptor agonist developed for the treatment of OAB, with a mechanism of action distinct from that of antimuscarinics. In a randomized, double-blind, placebo- and active-controlled Phase 3 trial conducted in Europe and Australia (NCT00689104), mirabegron 50 mg and 100 mg resulted in statistically significant reductions from baseline to final visit, compared with placebo, in the co-primary end points - mean number of incontinence episodes/24 h and mean number of micturitions/24 h. We conducted a post hoc, subgroup analysis of this study in order to evaluate the efficacy of mirabegron in treatment-naïve patients and patients who had discontinued prior antimuscarinic therapy because of insufficient efficacy or poor tolerability. METHODS: Patients were randomized to placebo, mirabegron 50 or 100 mg, or tolterodine extended release (ER) 4 mg orally, once-daily, for 12 weeks. For the post hoc analysis, the primary patient population was divided into the following subgroups: (1) patients who had not received any prior antimuscarinic OAB medication (treatment-naïve) and (2) patients who had received prior antimuscarinic OAB medication. The latter subgroup was further subdivided into patients who discontinued due to: (3) insufficient efficacy or (4) poor tolerability. Analysis of the co-primary efficacy endpoints by subgroup was performed using analysis of covariance with treatment group, subgroup, sex, geographical region, and subgroup-by-treatment interaction as fixed factors; and baseline value as a covariate. RESULTS: Mirabegron, 50 mg and 100 mg once-daily, demonstrated similar improvements in the frequency of incontinence episodes and micturitions in OAB patients who were antimuscarinic-naïve and who had discontinued prior antimuscarinic therapy. While mirabegron demonstrated improvements in incontinence and micturition frequency in patients who had discontinued prior antimuscarinic therapy due to insufficient efficacy, the response to tolterodine was similar to that of placebo. CONCLUSION: In this post hoc subgroup analysis, mirabegron provided treatment benefits in OAB patients who were antimuscarinic treatment-naïve and in patients who had received prior antimuscarinic treatment.

Randomized Controlled Trial of Subcutaneous Epoetin Alfa-epbx Versus Epoetin Alfa in End-Stage Kidney Disease.

INTRODUCTION: This double-blind, randomized controlled trial compared the safety and efficacy of subcutaneous epoetin alfa-epbx, an epoetin alfa biosimilar, with the reference product, epoetin alfa, in hemodialysis patients with end-stage kidney disease (ESKD) and anemia who were receiving epoetin alfa maintenance treatment. METHODS: Eligible patients (n = 320) were randomized (1:1) to subcutaneous epoetin alfa-epbx or epoetin alfa in a titration phase; patients who demonstrated stable subcutaneous dosing (n = 246) were re-randomized to receive subcutaneous epoetin alfa-epbx or epoetin alfa 1 to 3 times per week in a 16-week maintenance phase. Co-primary endpoints were least-squares mean difference between treatments in mean weekly hemoglobin concentration and mean weekly epoetin dose per kilogram body weight (BW) during the last 4 weeks of treatment in the maintenance phase. RESULTS: The least-squares mean difference (95% confidence interval [CI]) between treatments in weekly hemoglobin was 0.04 g/dl (-0.17 to 0.24 g/dl) and weekly epoetin dose/kg BW was -2.34 U/kg per week (-14.51 to 9.82 U/kg per week). The 95% CIs were contained within the prespecified equivalence margins of ±0.5 g/dl (weekly hemoglobin) and ±45 U/kg per week (weekly epoetin dose/kg BW). In the epoetin alfa-epbx and epoetin alfa groups, respectively, 4.0% and 4.1% of patients required blood transfusions, 69.7% and 70.5% reported adverse events, 18.9% and 27.0% reported serious adverse events, and 3 and 2 deaths were reported. Five patients were confirmed positive for anti-recombinant human erythropoietin antibody, 2 of whom tested positive at baseline. All patients tested negative for neutralizing antibodies. CONCLUSIONS: This comparative clinical trial demonstrated equivalence in efficacy and similar safety of subcutaneously administered epoetin alfa-epbx to epoetin alfa.

Long-term Safety of Epoetin Alfa-epbx for the Treatment of Anemia in ESKD: Pooled Analyses of Randomized and Open-label Studies.

RATIONALE & OBJECTIVE: Epoetin alfa-epbx is a biosimilar to the reference product, epoetin alfa. We compare the safety of epoetin alfa-epbx versus epoetin alfa based on a pooled analysis of findings from 2 randomized, double-blind, comparative clinical studies, and report new data for the long-term safety of epoetin alfa-epbx. STUDY DESIGN: Pooled analyses of previously conducted studies. SETTING & PARTICIPANTS: Hemodialysis patients with anemia. INTERVENTIONS: Data from patients who received 1 or more subcutaneous or intravenous doses of study drug were integrated across route of administration in combined randomized groups (epoetin alfa-epbx, n = 423; epoetin alfa, n = 426). Data from patients who received 1 or more doses of epoetin alfa-epbx in either open-label extension trial were integrated across route of administration in a combined long-term safety studies group (n = 576). OUTCOMES: Adverse events (AEs), immunogenicity, and other outcomes were assessed. RESULTS: Incidences of treatment-emergent AEs, serious AEs, and discontinuation of study drug treatment because of treatment-emergent AEs were similar between combined randomized epoetin alfa-epbx and epoetin alfa, which had mean treatment durations of 18.1 and 17.7 weeks, respectively. Incidences of treatment-emergent AEs, serious AEs, and discontinuation of study drug treatment because of treatment-emergent AEs were 86.5%, 39.4%, and 6.6%, respectively, for the combined long-term safety studies group, which had a mean treatment duration of 40.0 weeks. In total, 12 patients across the combined randomized groups (epoetin alfa-epbx, n = 5; epoetin alfa, n = 7) and 9 patients in the combined long-term safety studies group tested anti-recombinant human erythropoietin antibody positive in 1 or more visits during study conduct. No patient in any group developed neutralizing antibodies or pure red blood cell aplasia. LIMITATIONS: Epoetin alfa comparator not included in the long-term safety studies, greater cumulative exposure to study drug for epoetin alfa-epbx, shorter follow-up in the randomized studies, and potential for selection bias among patients in the open-label long-term safety studies. CONCLUSIONS: This analysis reinforces previous conclusions of similar safety profiles between epoetin alfa-epbx and epoetin alfa. Furthermore, epoetin alfa-epbx had no unexpected safety signals during long-term treatment. FUNDING: This study was funded by Hospira Inc, which was acquired by Pfizer Inc in September 2015. TRIAL REGISTRATION: ClinicalTrials.gov EPOE-10-13 (NCT01473420); EPOE-10-01 (NCT01473407); EPOE-11-04 (NCT01628120); EPOE-11-03 (NCT01628107).

Intravenous Epoetin Alfa-epbx versus Epoetin Alfa for Treatment of Anemia in End-Stage Kidney Disease.

BACKGROUND AND OBJECTIVES: This study was conducted to compare the safety and efficacy of intravenous epoetin alfa-epbx, an epoetin alfa biosimilar, to epoetin alfa in patients on hemodialysis with ESKD and anemia. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this 24-week, multicenter, double-blind comparative efficacy and safety study, 612 patients on hemodialysis with ESKD and anemia who had stable hemoglobin and were receiving stable doses of intravenous epoetin alfa were randomized (1:1) to intravenous epoetin alfa or epoetin alfa-epbx. Dosing was adjusted according to the epoetin alfa prescribing information. The coprimary efficacy end points were the least squares mean difference between the two treatments in mean weekly hemoglobin level and mean weekly epoetin dose per kilogram of body weight during the last 4 weeks of treatment. RESULTS: The least squares mean difference between epoetin alfa-epbx and epoetin alfa in weekly hemoglobin was -0.12 g/dl and the 95% confidence interval (-0.25 to 0.01) was contained within the prespecified equivalence margin (-0.5 to 0.5 g/dl). The least squares mean difference between epoetin alfa-epbx and epoetin alfa in weekly epoetin dose per kilogram of body weight was 0.37 U/kg per week, and the 95% confidence interval (-10.40 to 11.13) was contained within the prespecified equivalence margin (-45 to 45 U/kg per week). Incidences of adverse events (77.1% versus 75.3%), serious adverse events (24.9% versus 27.0%), and deaths (n=5 versus 6) were similar between the epoetin alfa-epbx and epoetin alfa groups, respectively. Five patients tested positive for anti-recombinant human erythropoietin antibodies at baseline, and two additional patients (n=1 per group) developed anti-recombinant human erythropoietin antibodies while on study treatment. All patients tested negative for neutralizing antibodies, and no patient in either group experienced an event of pure red cell aplasia. CONCLUSIONS: This 24-week, comparative, clinical trial in patients on hemodialysis with ESKD and anemia demonstrated there is no clinically meaningful difference in efficacy or safety between epoetin alfa-epbx and epoetin alfa.

Pharmacokinetic and Pharmacodynamic Equivalence of Epoetin Hospira and Epogen After Single Subcutaneous Doses to Healthy Male Subjects.

PURPOSE: The purpose of this study was to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) equivalence of single 100 U/kg subcutaneous doses of Epoetin Hospira and Epogen in healthy male subjects as part of an overall program to demonstrate biosimilarity of Epoetin Hospira to the reference product Epogen. METHODS: This single-center, open-label, randomized, 2-period, crossover study was conducted in 81 healthy male subjects. Subjects were randomized to Sequence 1, in which they received 100 U/kg of Epoetin Hospira or to sequence 2, in which they received 100 U/kg Epogen subcutaneously in the first study period and the alternative treatment in the second study period. Blood was collected for determination of baseline-adjusted epoetin concentrations (BAECs) for pharmacokinetics and for determination of reticulocyte percentage of total erythrocytes for pharmacodynamics throughout both study periods. The primary PK end points were the geometric mean ratios (GMRs) of the 2 treatments for AUC0-t and Cmax based on the BAEC, and the primary PD end points were the GMRs of the 2 treatments for AUC0-t and Cmax for reticulocyte percentage. FINDINGS: The GMRs of Epoetin Hospira to Epogen for the BAEC-derived PK parameters were 1.05 for AUC0-t with a 90% CI of 1.01 to 1.11, and 1.09 for Cmax with a 90% CI of 1.01 to 1.18, with both 90% CIs contained within the prespecified equivalence margin of 0.80 to 1.25. The GMRs (Epoetin Hospira/Epogen) for the reticulocyte percentage-derived PD parameters were 1.01 for AUC0-t with a 95% CI of 0.98 to 1.05, and 1.02 for Cmax with a 95% CI of 0.98 to 1.06, with both 95% CIs contained within the prespecified equivalence margin of 0.80 to 1.25. Overall, the adverse events were of similar frequency (11.7% and 13.9% for Epoetin Hospira and Epogen, respectively) and severity between treatments. One subject had a positive anti- recombinant human erythropoietin antibody result by radioimmunoprecipitation assay before dosing and throughout the conduct of the study with negative neutralizing antibodies and with no evidence of clinical deterioration or impact on the pharmacokinetics, pharmacodynamics, or safety. IMPLICATIONS: The results of this study established the PK and PD equivalence of single 100 U/kg subcutaneous doses of the proposed biosimilar Epoetin Hospira to the reference product Epogen in healthy male subjects and support the overall demonstration of biosimilarity of Epoetin Hospira and Epogen.

The effect of food on the pharmacokinetics of a dual angiotensin-converting enzyme/neutral endopeptidase inhibitor, M100240.

M100240 is a thioester of MDL 100,173, a dual angiotensin-converting enzyme (ACE)/neutral endopeptidase (NEP) inhibitor. Clinical studies have shown that M100240 is capable of decreasing ACE activity and angiotensin II concentrations while increasing plasma renin activity and potentiating the effects of atrial natriuretic peptide. This may result in a unique treatment benefit in disease states characterized by intravascular volume or sodium overload or increased venous pressure. The pharmacokinetics of MDL 100,173 were evaluated in 30 healthy subjects in an open-label, randomized, 2-period crossover design. Subjects received a single oral dose of 50 mg of M100240 administered with a high-fat meal and separately under fasted conditions. Serial plasma concentrations of M100240 and MDL 100,173 were analyzed, and pharmacokinetic parameters were calculated with noncompartmental methods. The intrasubject percent coefficient of variation for MDL 100,173 C(max) and AUC(0-24h) were less than 20%, indicating that this agent is a moderately variable drug. Although AUC(0-24h) was within the protocol-defined range of 80% to 125%, the lower limit of the 90% confidence interval for C(max) fell outside of the 70% to 143% range. Absence of a food effect on the pharmacokinetic profile of 50 mg of M100240 could therefore not be demonstrated. This finding is not surprising based on the documented food effect with the sulfhydryl-containing ACE inhibitor, captopril. Clinical significance of this pharmacokinetic food effect is unlikely, as the magnitude of pharmacodynamic response is probably better correlated with AUC than a single-point determination of C(max). Single oral doses of 50 mg of M100240 were safe and well tolerated under fed and fasted conditions.

Optimizing dose selection with modeling and simulation: application to the vasopeptidase inhibitor M100240.

Dual inhibition of neutral endopeptidase 24.11 (NEP) and angiotensin-converting enzyme (ACE) has gained increasing interest in the treatment of hypertension, heart failure, and renoprotection. Specifically, M100240, the thioester of the dual ACE/NEP inhibitor MDL100,173, has been evaluated in the management of hypertension. A model-based analysis, including simulations, was employed to characterize the relationship between individual M100240 drug exposure and neurohormonal response and to optimize the dose selection for future clinical studies. Sixty-two healthy subjects and 189 hypertensive patients were studied after oral once-daily administration of 2.5, 5, 10, 25, or 50 mg M100240. Pharmacokinetic-biomarker and blood pressure response models were fitted to the data with the computer program NONMEM. A direct inhibitory E(max) model adequately described the relationship between MDL100,173 concentration and ACE activity. No clear concentration or dose-dependent NEP or blood pressure responses were evident. Given a target 90% ACE inhibition, simulation reveals that (1). 50 mg M100240 once daily produces adequate ACE inhibition 24 hours postdose in only 20% of subjects, and (2). higher and/or more frequent doses on the order of 25 mg three times daily or 50 mg twice daily are required to achieve the target ACE inhibition in at least 50% of patients over 24 hours. Insufficient blood pressure-lowering effects were observed in healthy subjects and hypertensive patients due to inadequate ACE and NEP inhibition with once-daily oral doses of up to 50 mg of M100240. Divided doses might provide target ACE inhibition in more patients.

No clinically relevant CYP3A induction with the dual angiotensin-converting enzyme/neutral endopeptidase inhibitor, M100240.

M100240, an acetate thioester of MDL 100,173, is a dual angiotensin-converting enzyme/neutral endopeptidase inhibitor currently in Phase II development. M100240 and MDL 100,173 were evaluated in an in vitro cytochrome P450 human hepatocyte model for enzyme induction. Although a dose-dependent CYP3A induction was observed between 10 and 100 microM, at 1 microM-which approaches clinically relevant plasma concentrations in humans-there was no evidence of CYP3A induction. An in vitro reporter gene assay also demonstrated the CYP3A isozyme induction potential of M100240 and MDL 100,173 with an EC(50) approximately 1.5 microM. The present study evaluated the potential for CYP3A enzyme induction in healthy volunteers. In an open-label, single-sequence, replicate-design study using midazolam as a CYP3A probe in 13 healthy volunteers, we found no evidence of clinically relevant CYP3A induction after multiple-dose administration of 50 mg M100240 orally once daily for 15 days. Single and multiple doses of M100240 increased the midazolam AUC(0-24 h) about 1.6-fold compared to baseline, suggesting weak CYP3A inhibition. Concomitant administration of midazolam and M100240 was generally safe and well tolerated. Although in vitro CYP3A induction at exposures in excess of clinically relevant human plasma concentrations has been demonstrated, there is no clinical evidence of CYP3A induction with M100240 administration at proposed therapeutic doses.

Pharmacokinetics of M100240 and MDL 100,173, a dual angiotensin-converting enzyme/neutral endopeptidase inhibitor, in healthy young and elderly volunteers.

M100240 is an acetate thioester of MDL 100,173-a dual angiotensin-converting enzyme (ACE)/neutral endopeptidase (NEP) inhibitor-in phase II development. The pharmacokinetics of M100240 and MDL 100,173 were compared in young and elderly subjects. Pharmacokinetic data were obtained from 12 young (ages 18-45 years, 10 male, 2 female) and 12 elderly (ages 65-85 years, 7 male, 5 female) healthy subjects in a parallel-group, open-label study. Following an overnight fast, subjects received a single 25-mg oral dose of M100240. Serial plasma concentrations of M100240 and MDL 100,173 were determined using a validated liquid chromatography/tandem mass spectrometry (LC/MS/MS) method, and pharmacokinetic parameters were calculated with noncompartmental methods. Single-dose treatment with M100240 was well tolerated in both groups of subjects, with no clinically significant changes in vital signs, ECG recordings, or laboratory safety parameters. M100240 was rapidly absorbed and converted to MDL 100,173, with M100240 concentrations no longer detectable at 3 to 4 hours postdose in both groups. The pharmacokinetics of the pharmacologically active MDL 100,173 were similar for both groups. Although maximum concentrations of M100240 were generally higher in elderly versus young subjects (C(max) 0.48 ng/mL vs. 0.17 ng/mL), systemic availability of M100240 was quite low and variable with plasma, and this apparent difference in parent drug exposure is unlikely to have important clinical implications. No age-related differences in the pharmacokinetic parameters of MDL 100,173 (C(max) 8.16 vs. 9.62 ng/mL, t(max) 1.25 vs. 1.5 h, AUC((0-last)) 81.6 vs. 72.2 ng x h/mL) were observed between young and elderly subjects, respectively. In conclusion, there are no age-related differences in the pharmacokinetics of MDL 100,173 between young and elderly subjects.

Pharmacoscintigraphic assessment of the regional drug absorption of the dual angiotensin-converting enzyme/neutral endopeptidase inhibitor, M100240, in healthy volunteers.

M100240 is the thioester of MDL 100,173, a dual angiotensin-converting enzyme (ACE)/neutral endopeptidase (NEP) inhibitor currently in phase II development. The purpose of this study was to evaluate the relative bioavaibility of M100240 in various regions of the gastrointestinal tract using the Enterion capsule, a noninvasive radiocontrolled device providing targeted drug delivery, to explore the absorption characteristics of M100240 in healthy volunteers. In addition, the absolute bioavailability of an immediate-release formulation of M100240 was assessed. Pharmacokinetic data were obtained from 13 healthy subjects in an open-label, single-dose, randomized, five-period crossover study. Treatments included 25 mg M100240 administered via short intravenous infusion, oral immediate-release tablet administration, and oral Enterion capsule delivery of drug substance to the proximal small bowel, distal small bowel, and ascending colon. Each treatment was separated by a 14-day drug-free washout period. The localization of the Enterion capsule in the gastrointestinal tract was monitored using scintigraphic imaging. M100240 and MDL 100,173 plasma concentrations were quantified using a validated LC/MS/MS method, and pharmacokinetic parameters were calculated using noncompartmental methods. The estimates of relative bioavailability in the proximal small bowel, distal small bowel, and ascending colon relative to the oral immediate-release tablet are approximately 94%, 97%, and 41%, respectively. M100240 is primarily absorbed throughout the proximal and distal small bowel with modest absorption in the ascending colon. The absolute bioavailability estimate of the M100240 immediate-release formulation is 49%. These data characterize the fundamental in vivo performance attributes of M100240, thereby providing an approach for optimizing prototype modified-release formulations for this compound.

Site-specific absorption of M100240 and MDL 100,173 in rats evaluated using Sweetana-Grass diffusion chamber technology.

INTRODUCTION: M100240--an acetate thioester of MDL 100,173--a dual angiotensin-converting enzyme (ACE)/neutral endopeptidase (NEP) inhibitor is in Phase II development for cardiovascular conditions. The absorption characteristics of M100240 and MDL 100,173 were evaluated in specific regions of the rat gastrointestinal (GI) tract. METHODS: Solutions of M100240 and MDL 100,173 were prepared using mucosal Kreb's solution. Four male Sprague-Dawley rats, fasted before tissue procurement, were sacrificed using 95% CO2 and 5% O2. The entire small and large intestine were removed, rinsed in serosal Kreb's solution, and segments mounted onto the Sweetana-Grass diffusion chamber. Test compounds were added to the donor compartment and drug-free oxygenated serosal Kreb's solution to the receiving compartment. The temperature of the chambers was maintained at 37 degrees C and supplied with 95% O2/5% CO2. Samples were removed (0.5 ml) at 0, 30, 60, 90, 120, 180, and 240 min from the serosal side. The volume was maintained with drug-free warm serosal Kreb's solution. Samples were diluted with rabbit plasma and analyzed by liquid chromatography/mass spectrometry. Apparent permeation values [Papp (cm/min)] of M100240 and MDL 100,173 through the duodenum, jejunum, ileum, and colon were determined. RESULTS: The mean Papp of M100240 and MDL 100,173 was highest in the duodenum: 2.29 x 10(-4) +/- 2.40 x 10(-4) and 1.66 x 10(-4) cm/min +/- 8.33 x 10(-5), respectively. The mean Papp was lowest in the colon: 3.61 x 10(-6) +/- 3.44 x 10(-6) and 1.62 x 10(-5) +/- 3.21 x 10(-6) cm/min for M100240 and MDL 100,173, respectively. Absorption of MDL 100,173, however, was evident throughout the rat GI tract. DISCUSSION: M100240 and MDL 100,173 are predominantly absorbed from the duodenum in the rat GI tract. MDL 100,173 is also absorbed from the jejunum, ileum, and colon. These results, consistent with data obtained in humans, demonstrate the potential predictive value of the Sweetana-Grass model for site of absorption assessments.

Permeation prediction of M100240 using the parallel artificial membrane permeability assay.

PURPOSE: Kansy et al first introduced the Parallel artificial membrane permeation assay (PAMPA) in 1998. In this system, the permeability through a membrane formed by a mixture of lecithin and an inert organic solvent on a filter support is assessed. PAMPA shows definite trends in the ability of molecules to permeate membranes by transcellular passive diffusion. Its simplicity, low cost, high throughput, and wide pH range make it very attractive in modern drug discovery. Based on this concept, Whohnsland et al, Sugano et al and Zhu et al modified the assay and used it to screen compound permeability. We used PAMPA for the permeation prediction of M100240, which was unable to be determined by cell-based assays due to compound instability. METHODS: In this study, 92 commercially available agents provided the structural diversity used to generate a mathematical prediction model for human fraction absorbed, M100240--an acetate thioester of MDL 100,173. Permeation of M100240 and MDL 100,173 was evaluated using the parallel artificial membrane permeability assay (PAMPA). The donor and recipient solutions consisted of 0.5N HCl (pH 1.5) or phosphate-buffered saline (pH 5.5 or 7.4) with 2% dimethyl sulfoxide. The donor solution also contained 200 mM M100240 or MDL 100,173. RESULTS: M100240 had a medium permeation at pH 5.5 (2.99%), corresponding to a high predicted Fa in humans (92%). Permeation of MDL 100,173 was low at this pH (0.72%), corresponding to a medium-to-low predicted Fa (46). At pH 7.4, the permeation of M100240 was low (approximately 1%) and no permeation was apparent for MDL 100,173. CONCLUSIONS: We predicted M100240 is likely to be well absorbed via passive diffusion across the human gastrointestinal tract following oral administration.

Randomized, double-masked, placebo-controlled study to assess the ocular safety of mirabegron in healthy volunteers.

PURPOSE: This study assessed the effect of mirabegron on ocular safety in healthy volunteers. METHODS: This was an 8-week, randomized, double-masked, placebo-controlled study. PARTICIPANTS: Consenting adults aged ≥18 years with a normal intraocular pressure (IOP, ≥10 to ≤21 mmHg) were eligible to enter the study. Of the 321 randomized subjects, 305 completed the study. Subjects were randomized 1:1 to a supratherapeutic dose of oral mirabegron 100 mg or placebo once daily for 56 days. The IOP was measured at screening, baseline, day 10, and day 56/end of treatment using Goldmann applanation tonometry. Visual acuity and biomicroscopy were also evaluated. The primary endpoint was the mean change from baseline in the IOP at 56 days or end of treatment with mirabegron versus placebo. Secondary outcome variables included change from baseline to day 10 in the IOP, and increases in the IOP of ≥6 mmHg and ≥10 mmHg in either eye from baseline to day 10 and day 56. RESULTS: The mean (standard error, SE) IOP at baseline was 15.3 (0.16) mmHg for mirabegron and 15.4 (0.16) mmHg for placebo; values at day 56 were 15.0 (0.16) mmHg and 15.2 (0.17) mmHg, respectively. The adjusted mean IOP change from baseline to day 56 was -0.3 mmHg for mirabegron and -0.2 mmHg for placebo (-0.1 mmHg difference [95% confidence interval, CI, -0.4 to 0.3]). For the primary endpoint, mirabegron was noninferior to placebo, based on the prespecified limit of 1.5 mmHg. No statistically significant treatment effects on the IOP were seen at day 10. No subject discontinued due to increased IOP. Clinically significant increases from baseline in the IOP occurred rarely and only with placebo treatment. Changes in the visual acuity and biomicroscopy were not suggestive of a mirabegron effect. No treatment-emergent adverse event (AE) of glaucoma was reported. CONCLUSIONS: Mirabegron 100 mg orally once daily for 8 weeks of treatment does not increase the IOP, and was generally safe and well tolerated.

Fibrin sealant for retinoblastoma: where are we?

Chemoreduction is currently the most popular treatment strategy for intraocular retinoblastoma worldwide. Despite the dramatic clinical responses obtained with multiagent systemic chemotherapy regimens, enthusiasm for this treatment approach has been tempered by the potential toxicities of these drugs in the pediatric population. As a response to these concerns, novel approaches for the local delivery of chemotherapeutic agents to ocular structures have been investigated by both clinicians and scientists. Ocular oncologists have developed the periocular injection of carboplatin as a method for controlling intraocular tumor growth of retinoblastoma while minimizing systemic drug exposure. In parallel, the pharmaceutical industry has introduced drug-delivery systems to the posterior segment of the globe for a variety of ocular diseases. One example of the collaborative work by ophthalmologists and biopharmaceutical scientists is the use of fibrin sealants as a targeted drug-administration device, formulated to deliver sustained concentrations of chemotherapy at the site of application. This review integrates the recent ophthalmology and pharmaceutics literature on the potential role of fibrin sealants for periocular chemotherapy administration in the treatment of retinoblastoma.

Eplerenone: selective aldosterone antagonism in management of cardiovascular and renal disease.

OBJECTIVE: To review the pharmacology, safety, and efficacy data, as well as therapeutic use of eplerenone (Inspra-Pfizer) for management of cardiovascular and renal disease. DATA SOURCES: A Medline search (January 1980-July 2003) was performed using eplerenone, aldosterone, aldosterone antagonist, spironolactone, and other pertinent terms. Additional articles were identified from bibliographies of retrieved articles. STUDY SELECTION: All retrievable studies and review articles discussing the pharmacology, safety, and efficacy of eplerenone were evaluated. DATA EXTRACTION: By the authors. DATA SYNTHESIS: The detrimental role of the renin-angiotensin-aldosterone system (RAAS) in the pathophysiology of cardiovascular and renal disease has been well documented. Until recently, however, the direct injurious effects of aldosterone on nonclassical tissues such as the brain, heart, and vasculature have been overlooked. Although angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) significantly reduce morbidity and mortality associated with heart disease, preliminary data suggest further benefit with additional aldosterone blockade. The nonselective aldosterone antagonist spironolactone has demonstrated profound morbidity and mortality benefit in heart failure patients, but since its adverse event profile makes it unattractive to patients with milder disease, the need for a selective aldosterone receptor antagonist is evident. Preclinical studies with eplerenone, a recently approved selective aldosterone receptor antagonist, demonstrate a protective effect on nonclassical tissues, thus reducing injury associated with long-term unopposed aldosterone exposure. Early clinical trials with eplerenone have demonstrated additional benefit in hypertension, heart failure, and nephropathy, although long-term morbidity and mortality outcome data in patients with various levels of disease severity are necessary to define the role of eplerenone in current cardiovascular pharmacotherapy. CONCLUSION: Eplerenone offers a new selective approach to optimizing aldosterone blockade. The availability of additional morbidity and mortality outcome data in various cardiovascular conditions will provide further insights into its role in clinical practice.

Mass balance study of [14C]M100240, a dual angiotensin-converting enzyme/neutral endopeptidase inhibitor, in healthy male subjects.

[4S-[4alpha,7alpha(R*),12bbeta]]-7[[2-(acetylthio)-1-oxo-3-phenylpropyl]amino]-1,2,3,4,6,7,8,12b-octahydro-6-oxo-pyrido[2,1-a][2]benzazepine-4-carboxylic acid (M100240) is an acetate thioester of MDL 100,173-a dual angiotensin-converting enzyme/neutral endopeptidase inhibitor currently in phase II development. The mass balance of [(14)C]M100240 was assessed following oral administration of [(14)C]M100240. Healthy male subjects were given a single 25-mg dose of [(14)C]M100240 (50 microCi) as an oral solution under fasting conditions. Blood samples and excreta were collected postdose. (14)C-radioactivity was measured by liquid scintillation counting. Plasma concentrations of M100240 and MDL 100,173 were determined by LC/MS/MS methods. Pharmacokinetic parameters were calculated. About 98% of the total radioactive dose was recovered within 7 days of oral administration, with most of the radioactivity recovered within 72 hours. Of the recovered radioactive dose, 49.4% and 48.5% were recovered in the urine and feces, respectively. Unchanged M100240 and MDL 100,173 were not detected in the excreta. On average, 76% of the total radioactivity in the blood was associated with the plasma fraction. M100240 accounted for less than 0.06% of the (14)C-radioactivity in plasma and MDL 100,173 accounted for 15.8% (AUC( infinity )) of (14)C-radioactivity in plasma after oral dosing. These data suggest that the drug was absorbed but rapidly converted to its metabolites either presystemically or postsystemically. Up to 78% of the total radioactivity was identified as MDL 100,173. The apparent terminal elimination half-life of MDL 100,173 was longer than that of (14)C-radioactivity, attributable to assay sensitivity and the saturable binding phenomenon commonly associated with angiotensin-converting enzyme inhibitors. M100240 undergoes extensive metabolism in humans, and its metabolites are excreted relatively equally in feces and urine.