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Background Lorlatinib demonstrated efficacy (including intracranial activity) in patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) in a phase I/II study (NCT01970865). Background and Objective This analysis describes the pharmacokinetics (PK) of lorlatinib following single and multiple dosing. Methods This ongoing, multicenter, open-label, single-arm, phase I/II trial enrolled patients with ALK-positive or c-ros oncogene 1 (ROS1)-positive advanced NSCLC. In phase I, patients received escalating doses of lorlatinib (10–200 mg orally once daily) and twice-daily doses of 35, 75, and 100 mg in continuous 21-day cycles. In phase II, lorlatinib was administered at a starting dose of 100 mg once daily in continuous 21-day cycles. Parameters investigated included the potential for lorlatinib to inhibit/induce cytochrome P450 (CYP) 3A; the absorption/metabolism of lorlatinib and its major metabolite PF-06895751; and differences in these parameters between Asian and non-Asian patients. Results Data were available for 54 patients from phase I and 275 patients from phase II. Lorlatinib plasma exposure increased dose proportionally after single doses of 10–200 mg, and slightly less than dose proportionally after multiple doses. Lorlatinib clearance increased following multiple dosing compared with single dosing, indicating autoinduction. The area under the concentration-time curve from time zero to time τ (the dosing interval; AUCτ) of PF-06895751 was approximately 80% higher than that of lorlatinib after multiple dosing. Lorlatinib exhibited brain penetration. Furthermore, no overt differences in single- and multiple-dose PK parameters between the Asian and non-Asian patients were observed. Conclusions Lorlatinib is highly brain penetrant and exhibits autoinduction after multiple dosing. There appears to be no inherent differences in lorlatinib PK between healthy subjects and cancer patients, or between Asian and non-Asian patients. ClinicalTrials.gov NCT01970865. Supplementary Information The online version contains supplementary material available at 10.1007/s40262-021-01015-z.

Age-related Macular Degeneration (AMD) is the leading cause of visual impairment and blindness in the elderly in developed countries. Neovascular/exudative (wet) AMD is the aggressive form of AMD and can involve choroidal neovascularization and vascular leakage. Anti-vascular endothelial growth factor (anti-VEGF) medications have significantly improved treatment of wet-AMD. However, only approximately 40% of patients obtain full benefit from anti-VEGF therapy and the medications are given by intravitreal injection. Axitinib, a small molecule multi-receptor tyrosine kinase inhibitor used for the treatment of advanced renal cell carcinoma, is taken orally and inhibits VEGF activity by blocking VEGF receptors. Axitinib also has the advantage of blocking platelet derived growth factor (PDGF) receptors which play a role in neovascularization. Using in vitro human retinal microvascular endothelial cells (HRMVECs), human brain vascular pericytes (HBVRs), 3D co-culture vessel sprout assay, and in vivo laser induced rat choroidal neovascularization (CNV) models, the effect of axitinib on neovascularization was evaluated. Axitinib inhibited neovascularization better than anti-VEGF and/or anti-hPDGF-B mAb in the in vitro models demonstrating that combined inhibition of both VEGF and PDGF pathways may be synergistic in treating wet-AMD. Additionally, axitinib showed good efficacy at a low dose (0.875 mg/day) in laser-induced CNV model in rats. In conclusion our data shows that axitinib, an inhibitor of VEGF and PDGF-B pathways may be useful in ameliorating wet-AMD therapy.

Aims The transthyretin (TTR) stabilizer, tafamidis, has demonstrated efficacy and safety in the treatment of TTR familial amyloid polyneuropathy (20 mg day−1). Tafamidis use in TTR cardiomyopathy led to the study of the potential effect of tafamidis on the QTc interval in healthy subjects. Methods This randomized, three treatment, three period, six sequence crossover study with placebo, a positive control (moxifloxacin 400 mg) and tafamidis (400 mg, to achieve a supra-therapeutic Cmax of ~20 µg ml−1) was conducted in healthy volunteers at three clinical research units. Oral dosing in each of the three treatment periods was separated by a washout period of ≥ 14 days. Serial triplicate 12-lead electrocardiograms were performed. QTc intervals were derived using the Fridericia correction method. Safety and tolerability were assessed by physical examination, vital signs measurement, laboratory analyses and monitoring of adverse events (AEs). Results A total of 42 subjects completed the study. The upper limit of the two-sided 90% confidence intervals (CIs) for the difference in baseline-adjusted QTcF between tafamidis 400 mg and placebo was

Tofacitinib is a novel, oral Janus kinase inhibitor. The potential for drug-drug interactions (DDIs) between tofacitinib and drugs that undergo renal tubular secretion was evaluated using metformin as a probe transporter substrate, and genotyping for organic cation transporter (OCT) 1, OCT2 and multidrug and toxin extrusion 1 polymorphisms. Twenty-four healthy male subjects completed this open-label, fixed-sequence study. Subjects were administered a single oral metformin 500 mg dose on Days 1 and 4, and multiple oral tofacitinib 30 mg twice daily doses on Days 2, 3, and 4. Subjects underwent serial blood and urine samplings (Days 1 and 4) to estimate metformin pharmacokinetics. A single blood sample for tofacitinib was collected 2 hours after the morning dose (Day 4). The 90% confidence intervals for the ratios of maximum plasma concentration, area under the curve and renal clearance of metformin, with and without tofacitinib, were contained within the 80-125% acceptance range commonly used to establish a lack of DDI. No deaths, serious adverse events (AEs), severe AEs or discontinuations due to AEs were reported. The study confirms tofacitinib is unlikely to impact the pharmacokinetics of drugs that undergo renal tubular secretion, and concurs with its weak in vitro OCT2 inhibitory profile.

Axitinib is a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2, and 3 that is approved in the US and several other countries for treatment of patients with advanced renal cell carcinoma after failure of one prior systemic therapy. The recommended clinical starting dose of axitinib is 5 mg twice daily, taken with or without food. Dose increase (up to a maximum of 10 mg twice daily) or reduction is permitted based on individual tolerability. Axitinib pharmacokinetics are dose-proportional within 1–20 mg twice daily, which includes the clinical dose range. Axitinib has a short effective plasma half-life (range 2.5–6.1 h), and the plasma accumulation of axitinib is in agreement with what is expected based on the plasma half-life of the drug. Axitinib is absorbed relatively rapidly, reaching maximum observed plasma concentrations (C max) within 4 h of oral administration. The mean absolute bioavailability of axitinib is 58 %. Axitinib is highly (>99 %) bound to human plasma proteins with preferential binding to albumin and moderate binding to α1-acid glycoprotein. In patients with advanced renal cell carcinoma, at the 5-mg twice-daily dose in the fed state, the geometric mean (% coefficient of variation) C max and area under the plasma concentration–time curve (AUC) from time 0–24 h (AUC24) were 27.8 ng/mL (79 %) and 265 ng·h/mL (77 %), respectively. Axitinib is metabolized primarily in the liver by cytochrome P450 (CYP) 3A4/5 and, to a lesser extent (

Palbociclib free base capsule is a weak base drug with highly pH-dependent solubility. In vitro and in vivo studies evaluated the impact of acid-reducing agents on exposure of palbociclib and determined whether the impact, if any, can be mitigated by food. A drug-drug interaction study (study 1) was conducted first under fasted conditions and showed that coadministration of multiple doses of the proton-pump inhibitor rabeprazole substantially reduced palbociclib mean area under the concentration-time curve from time 0 to infinity and maximum observed plasma concentration by 62% and 80%, respectively. In vitro assessment suggested that the presence of bile salt mixed micelles to mimic the fed state can significantly enhance the solubility of palbociclib. Subsequently, study 2 was conducted under fed conditions and demonstrated that coadministration of rabeprazole decreased palbociclib maximum observed plasma concentration by 41% but had limited impact on area under the concentration-time curve from 0 to infinity (13% decrease). This study also showed that the histamine-2 receptor antagonist famotidine and local antacid with staggered dosing had no impact on palbociclib exposure under fed conditions. Food intake effectively mitigated the impact of acid-reducing agents on palbociclib exposure. Palbociclib free base capsule should be taken with food, and acid-reducing agent use does not need to be avoided.

Objective To evaluate safety and efficacy of topical ophthalmic tofacitinib (CP-690,550), a novel Janus kinase inhibitor, in treating dry eye disease (DED). Design A phase 1/2 prospective, randomized, double-masked, multicenter, vehicle- and comparator-controlled trial (NCT00784719). Participants Patients (n = 327) 18 years of age and older with a DED diagnosis for 6 months or more. Methods Tofacitinib (0.0003% twice daily, n = 46; 0.001% in both eyes twice daily, n = 47; 0.003% twice daily, n = 48; 0.005% twice daily, n = 48; 0.005% once daily, n = 44) results were compared with those of groups receiving active treatment cyclosporine ophthalmic emulsion 0.05% twice daily (n = 47) and vehicle twice daily (n = 47). Safety and efficacy evaluations were performed at baseline and throughout the 8-week study. Main outcome measures Schirmer wetting, corneal staining, tear film break-up time, conjunctival staining, Ocular Comfort Index (OCI), and Ocular Surface Disease Index (OSDI). Results All tofacitinib doses were well tolerated, exhibiting better patient-reported ocular tolerability than cyclosporine. For the proportion of patients achieving 10 mm or more Schirmer wetting (without anesthesia) at week 8 (primary end point), greater response rates were observed in the tofacitinib 0.001% twice daily (27.3%), 0.005% twice daily (25.5%), and 0.005% once daily (26.1%) groups versus vehicle (20.0%); however, the differences were not statistically significant. Mean increase in Schirmer wetting (without anesthesia) from baseline was statistically significant (P Conclusions This phase 1/2 study of tofacitinib demonstrated a trend for improving both signs and symptoms of dry eye. All doses of tofacitinib exhibited a reasonable safety profile and were well tolerated by patients with DED.

The effect of food on the oral bioavailability of sunitinib malate (SU11248, an oral, multi-targeted tyrosine kinase inhibitor with anti-angiogenic and anti-tumor activities) was assessed in a randomized open-label, two-way crossover study. A 50-mg dose of SU11248 was administered to 16 healthy subjects after a 10-h fast in one period and after a high-fat, high-calorie meal in the other period. The 90% confidence intervals (CIs) for maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) were within the 80-125% bioequivalence range, indicating the absence of a food effect. SU11248 exposure increased slightly in the fed compared with the fasted state (ratios of fed/fasted geometric least square means: Cmax 104%, AUC0-last and AUC0-infinity both 112%). There was a delay in the formation/absorption of the active metabolite SU12662 in the fed state (mean Cmax decreased 23%), but exposure remained unaffected (90% CIs for AUC0-last and AUC0-infinity were within 80-125%). These results indicate that SU11248 can be administered with or without food.

OBJECTIVE To rapidly identify patients who will ultimately respond to 1 year of therapy, and optimize their inter dose interval. MATERIALS AND METHODS An intravitreal (IVT) ophthalmic dosing paradigm was designed based on clinical efficacy, nonclinical pharmacokinetics (PK), and disease progression modeling. Relevant non-clinical PK models were used to extrapolate IVT drug concentrations to patients. RESULTS Modeling predicted that > 80% of patients who would respond to 1 year of IVT treatment with an improvement in best-corrected visual acuity (BCVA) could be identified after the first 2 doses of treatment. These 2 initial doses produced ~ 75% of the maximum improvement in BCVA attainable. Moreover, the models also predicted those patients who responded after 1 year of treatment may tolerate an extension of the inter dose interval to 12 weeks without significant deterioration of BCVA. In contrast, > 70% of responsive patients who did not respond to 1 year of treatment showed inadequate responses after 2 doses. CONCLUSIONS These models use data from 2 doses to identify those patients likely to benefit after 1 year of treatment, and thereafter can lengthen their inter dose interval without deleterious effects. This method identifies potential treatment responders early, and lengthens the inter dose interval during long-term administration while allowing non-responders to pursue alternative therapies earlier, thereby minimizing risk to the patient.

The disposition of a single oral dose of 5 mg (100 μCi) of [(14)C]axitinib was investigated in fasted healthy human subjects (N = 8). Axitinib was rapidly absorbed, with a median plasma Tmax of 2.2 hours and a geometric mean Cmax and half-life of 29.2 ng/ml and 10.6 hours, respectively. The plasma total radioactivity-time profile was similar to that of axitinib but the AUC was greater, suggesting the presence of metabolites. The major metabolites in human plasma (0-12 hours), identified as axitinib N-glucuronide (M7) and axitinib sulfoxide (M12), were pharmacologically inactive, and with axitinib comprised 50.4%, 16.2%, and 22.5% of the radioactivity, respectively. In excreta, the majority of radioactivity was recovered in most subjects by 48 hours postdose. The median radioactivity excreted in urine, feces, and total recovery was 22.7%, 37.0%, and 59.7%, respectively. The recovery from feces was variable across subjects (range, 2.5%-60.2%). The metabolites identified in urine were M5 (carboxylic acid), M12 (sulfoxide), M7 (N-glucuronide), M9 (sulfoxide/N-oxide), and M8a (methylhydroxy glucuronide), accounting for 5.7%, 3.5%, 2.6%, 1.7%, and 1.3% of the dose, respectively. The drug-related products identified in feces were unchanged axitinib, M14/15 (mono-oxidation/sulfone), M12a (epoxide), and an unidentified metabolite, comprising 12%, 5.7%, 5.1%, and 5.0% of the dose, respectively. The proposed mechanism to form M5 involved a carbon-carbon bond cleavage via M12a, followed by rearrangement to a ketone intermediate and subsequent Baeyer-Villiger rearrangement, possibly through a peroxide intermediate. In summary, the study characterized axitinib metabolites in circulation and primary elimination pathways of the drug, which were mainly oxidative in nature.

Tofacitinib is a novel, oral Janus kinase inhibitor. The potential for drug-drug interactions (DDIs) between tofacitinib and drugs that undergo renal tubular secretion was evaluated using metformin as a probe transporter substrate, and genotyping for organic cation transporter (OCT) 1, OCT2 and multidrug and toxin extrusion 1 polymorphisms. Twenty-four healthy male subjects completed this open-label, fixed-sequence study. Subjects were administered a single oral metformin 500 mg dose on Days 1 and 4, and multiple oral tofacitinib 30 mg twice daily doses on Days 2, 3, and 4. Subjects underwent serial blood and urine samplings (Days 1 and 4) to estimate metformin pharmacokinetics. A single blood sample for tofacitinib was collected 2 hours after the morning dose (Day 4). The 90% confidence intervals for the ratios of maximum plasma concentration, area under the curve and renal clearance of metformin, with and without tofacitinib, were contained within the 80-125% acceptance range commonly used to establish a lack of DDI. No deaths, serious adverse events (AEs), severe AEs or discontinuations due to AEs were reported. The study confirms tofacitinib is unlikely to impact the pharmacokinetics of drugs that undergo renal tubular secretion, and concurs with its weak in vitro OCT2 inhibitory profile.

9009Background: Most patients (pts) with anaplastic lymphoma kinase (ALK) and c-ros oncogene 1 (ROS1) NSCLC develop resistance to tyrosine kinase inhibitor (TKI) therapy, with the central nervous system (CNS) as a common site of relapse. Lorlatinib is a selective brain-penetrant ALK/ROS1 TKI active against most known resistance mutations. Methods: In Ph. I of the ongoing Ph. I/II study NCT01970865, eligible pts had ALK+ or ROS1+ NSCLC with/without brain metastases (mets) and were treatment naive or had disease progression after ≥1 TKIs. Pts received lorlatinib on day –7 and daily from day 1. Primary objective was to identify the MTD and recommended Ph. II dose (RP2D). Other objectives were safety and efficacy by RECIST v1.1, including intracranial activity. Results: Of 54 pts treated in Ph. I as of Nov 30 2015, 41 were ALK+, 12 ROS1+; and 1 with mutation status not recorded at cut-off date. Pts were heavily pretreated:27 had received >1 prior TKI, 20 1 prior TKI and 7 were TKI naive; 39 pts had CNS mets a...

Objective To evaluate the efficacy of different dosing paradigms of PF-04523655 (PF) versus ranibizumab (comparator) in subjects with neovascular age-related macular degeneration (AMD). Design Multicenter, open-label, prospective, randomized, comparator-controlled exploratory study. Participants A total of 151 patients with subfoveal choroidal neovascularization (CNV) secondary to neovascular AMD who were naive to AMD therapy. Methods In this phase 2 study, patients were randomized to 1 of 5 treatment groups with equal ratio. All groups received ranibizumab 0.5 mg at baseline and (a) PF 1 mg every 4 weeks (Q4W) from week 4 to week 12; (b) PF 3 mg Q4W from week 4 to week 12; (c) PF 3 mg every 2 weeks (Q2W) from week 4 to week 12; (d) PF 1 mg + ranibizumab (combination) Q4W from baseline to week 12; and (e) ranibizumab Q4W to week 12. All study treatments were given as intravitreal injections. Main Outcome Measures The primary end point was the mean change in best-corrected visual acuity (BCVA) from baseline at week 16; secondary end points included the percentage of patients gaining ≥10 and ≥15 letters in BCVA and mean change in retinal central subfield thickness, lesion thickness, and CNV area. Results At week 16, the PF 1 mg + ranibizumab combination group achieved numerically greater improvement in mean BCVA from baseline (9.5 letters) than the ranibizumab group (6.8 letters). The difference was not statistically significant. The BCVA improvement in the PF monotherapy groups was less than in the ranibizumab group. Similar trends were observed in the percentage of patients who gained ≥10 and ≥15 letters. From baseline to week 16 (last observed carried forward), the combination and ranibizumab groups had similar mean reductions in central subfield retinal thickness and total CNV area, which were greater than in all PF monotherapy groups. There were no clinically meaningful differences in reduction of lesion thickness among treatment groups. Conclusions In this early, underpowered study evaluating treatments for neovascular AMD, the combination of PF with ranibizumab led to an average gain in BCVA that was more than with ranibizumab monotherapy. No safety concerns were identified. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.

To evaluate the effect of food on axitinib pharmacokinetics in healthy volunteers with two different crystal polymorphs.Two separate open-label, randomized, single-dose, three-period, crossover trials were conducted. Study I, conducted first using 5-mg axitinib Form IV film-coated immediate-release (FCIR) tablets, enrolled 18 subjects to compare fed versus fasted states and 24 subjects to evaluate the effect of timing of food consumption on axitinib pharmacokinetics. Study II enrolled 30 subjects to assess the effect of food using 5-mg axitinib Form XLI FCIR tablets. Subjects received axitinib after overnight fasting, with limited fasting or, depending on the study design, after consuming high-fat, high-calorie or moderate-fat, standard-calorie meals.For Form IV FCIR, compared with overnight fasting, axitinib plasma exposure [area under the concentration curve (AUC)] was decreased 23 % when administered with food. For Form XLI FCIR, mean axitinib plasma AUC and maximum plasma concentration (C(max)) were 19 and 11 % higher, respectively, with a high-fat, high-calorie meal compared with overnight fasting. When Form XLI FCIR was administered with moderate-fat, standard-calorie meal, AUC and C(max) were 10 and 16 % lower compared with overnight fasting. Both formulations were well tolerated. Adverse events, mostly gastrointestinal (7 % with Form IV FCIR and 13 % with Form XLI FCIR), were mild to moderate in both studies.While axitinib Form IV FCIR was associated with higher plasma exposure after overnight fasting, axitinib Form XLI FCIR can be administered with or without food as differences in axitinib pharmacokinetics under the two conditions were not clinically meaningful.

To evaluate safety and efficacy of topical ophthalmic tofacitinib (CP-690,550), a novel Janus kinase inhibitor, in treating dry eye disease (DED).A phase 1/2 prospective, randomized, double-masked, multicenter, vehicle- and comparator-controlled trial (NCT00784719).Patients (n = 327) 18 years of age and older with a DED diagnosis for 6 months or more.Tofacitinib (0.0003% twice daily, n = 46; 0.001% in both eyes twice daily, n = 47; 0.003% twice daily, n = 48; 0.005% twice daily, n = 48; 0.005% once daily, n = 44) results were compared with those of groups receiving active treatment cyclosporine ophthalmic emulsion 0.05% twice daily (n = 47) and vehicle twice daily (n = 47). Safety and efficacy evaluations were performed at baseline and throughout the 8-week study.Schirmer wetting, corneal staining, tear film break-up time, conjunctival staining, Ocular Comfort Index (OCI), and Ocular Surface Disease Index (OSDI).All tofacitinib doses were well tolerated, exhibiting better patient-reported ocular tolerability than cyclosporine. For the proportion of patients achieving 10 mm or more Schirmer wetting (without anesthesia) at week 8 (primary end point), greater response rates were observed in the tofacitinib 0.001% twice daily (27.3%), 0.005% twice daily (25.5%), and 0.005% once daily (26.1%) groups versus vehicle (20.0%); however, the differences were not statistically significant. Mean increase in Schirmer wetting (without anesthesia) from baseline was statistically significant (P0.2, 2-sided) for all tofacitinib doses (1.7-3.1 mm), cyclosporine (3.9 mm), and vehicle (1.4 mm). For corneal staining (total score), significant improvement (reduction) from baseline was observed for all tofacitinib doses (-0.9 to -1.9) and vehicle (-2.0), but not for cyclosporine. The proportion of patients with complete corneal clearing (CCC; 100%) at week 8 was greatest with tofacitinib 0.005% once daily (15.9%) versus vehicle (6.7%). Symptom scores (OCI, OSDI) at week 8 showed significant improvements from baseline for all tofacitinib groups, and tofacitinib demonstrated greater improvements than cyclosporine. The tofacitinib 0.005% once daily group showed significant improvements in both a sign (Schirmer wetting without anesthesia) and symptom (OSDI environmental triggers subscale) versus vehicle and also demonstrated the highest response rate for CCC (16.7%) at week 8.This phase 1/2 study of tofacitinib demonstrated a trend for improving both signs and symptoms of dry eye. All doses of tofacitinib exhibited a reasonable safety profile and were well tolerated by patients with DED.

The permeation of Bepridil through excised human skin was measured from vehicles composed of various mixtures of aqueous buffer and the permeation enhancers ethanol, DMSO or DMF. Only DMSO was found to act as a true permeation enhancer for the drug, the magnitude of its action depending on its concentration in the vehicle. At concentrations greater than 50% DMSO the permeability coefficient of the drug was increased over and above that which could be accounted for by changes in partitioning of the drug between vehicle and skin. The effects of ethanol could be related to changes in the measured skin/vehicle partition coefficients of the drug. DMF showed a complicated, concentration dependent influence on permeation.

The primary objective of this study was to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) of tasosartan and atenolol administered alone and concomitantly under steady-state conditions in 17 patients ages 18 to 65 years diagnosed with stage 1 to 2 essential hypertension. After a 3- to 14-day qualification period, all patients received placebo tasosartan on days--1 through 5 and 25 through 34, atenolol alone (50 mg) on days 1 through 5, atenolol (50 mg) + tasosartan (50 mg) on days 6 through 19, and tasosartan (50 mg) alone on days 20 through 24. A PK and PD evaluation of atenolol alone was performed on study day 5. On study day 19, PK and PD of both tasosartan and atenolol were assessed. PK and PD evaluation for tasosartan alone was assessed on study day 24. The coadministration of atenolol + tasosartan did not affect the pharmacokinetics of tasosartan, its major metabolite (enoltasosartan), or atenolol when compared with tasosartan or atenolol administered separately. For area under the change in diastolic blood pressure curve, the reduction was significantly greater after tasosartan + atenolol compared with that after atenolol alone (336 +/- 85 and 190 +/- 71 mmHg.24 h; p < 0.05 for combination and atenolol alone, respectively; mean +/- SEM). Combination therapy also caused a maximal reduction in diastolic blood pressure that is significantly more than with monotherapy with atenolol (-27 +/- 2 mmHg and -20 +/- 2 mmHg, respectively, p < 0.05). The additive effects of tasosartan and atenolol in decreasing diastolic blood pressure may provide a rationale for combination antihypertensive therapy.

To evaluate the potential need for modification of dose regimens of intravenous amiodarone in patients with left ventricular dysfunction, the pharmacokinetics of amiodarone and its active metabolite, desethylamiodarone (DEA), were examined after a single 15-minute intravenous infusion of amiodarone 5 mg/kg. Three parallel groups of otherwise healthy volunteers with normal (n = 12), moderately impaired (ejection fraction > 30 but < or = 45%; n = 6), or severely impaired (ejection fraction < or = 30%; n = 6) left ventricular function were enrolled in the study. Serial blood samples were obtained over a 76-day period for estimation of pharmacokinetic parameters. With the exception of the half-life (t1/2) of DEA, statistical comparisons revealed no significant between-group differences in pharmacokinetic parameters or correlations between pharmacokinetic parameters and ejection fractions. The t1/2 of DEA was increased by approximately 60% in patients with severe left ventricular dysfunction compared with that in patients with moderately impaired and normal left ventricular function. The rate of DEA formation is slow, however, and its concentration relative to amiodarone is low. Therefore, it is unlikely that concentrations of DEA in serum would reach levels that contribute significantly to the pharmacologic activity of amiodarone during short-term (up to 2 weeks) intravenous amiodarone therapy. Single doses of amiodarone were well tolerated. The results of this study suggest that intravenous amiodarone can be used with appropriate observation to control arrhythmias, regardless of the degree of left ventricular dysfunction.

In a study designed to determine the influence of renal dysfunction on the disposition of amiodarone and its metabolite, desethylamiodarone (DEA), 30 subjects received a single 5 mg/kg intravenous dose of amiodarone over 15 minutes. Of the 30, 11 had normal renal function (group I ; mean ± SD glomerular filtration rate [GFR] = 118 ± 20 mL/min/1.73 m 2 ), 9 had renal impairment (group II ; GFR = 23 ± 10 mL/min/1.73 m 2 ), and 10 were long-term hemodialysis patients (group 111 ; 4 of these patients were studied during dialysis). Total and free concentrations of amiodarone and DEA were measured by high-performance liquid chromatography. There were no significant differences between the three groups in mean systemic clearance, steady state volume of distribution, or mean residence time of amiodarone. However, the area under the concentration-time curve (AUC) for amiodarone was significantly higher in group I than in group II, and this finding was related to total body weight. Free fraction was similar in groups I and III. The disposition of amiodarone and its metabolite DEA was similar in patients with normal renal function, moderate renal dysfunction, and end-stage renal disease. Thus, dosage adjustment in patients with renal impairment is not necessary based on this pharmacokinetic analysis.

Venlafaxine is a structurally novel, nontricyclic compound that is being evaluated for the treatment of various depressive disorders. A randomized three-period crossover study was conducted to obtain pharmacokinetic and dose proportionality data on the drug and its active metabolite, O-desmethylvenlafaxine. Eighteen healthy young men received single doses of venlafaxine 25, 75, and 150 mg followed by 3 days of administration every 8 hours (q8h). Steady-state elimination half-life was 3 to 4 hours for venlafaxine and 10 hours for O-desmethylvenlafaxine; both were independent of dose. Venlafaxine had a high oral-dose clearance, ranging from 0.58 to 2.63 L/hr/kg across doses with the lowest mean clearance, 0.98 L/hr/kg, at the highest dose. The apparent clearance of O-desmethylvenlafaxine was lower than venlafaxine, ranging from 0.21 to 0.66 L/hr/kg, and the lowest mean clearance, 0.33 L/hr/kg, occurred at the lowest dose. The area under the metabolite curve was two to three times greater than that for venlafaxine. Each compound had linear dose proportionality up to 75 mg q8h. A composite parameter incorporating venlafaxine plus O-desmethylvenlafaxine was introduced (i.e., AUC [area under the curve] + activity factor.AUCm), which extended linearity to 150 mg q8h. In summary, venlafaxine is a high-clearance drug that forms a metabolite with almost equal activity and demonstrates linear dose-proportionality.

In a multicenter study, the efficacy and safety of intravenous (IV) labetalol for the control of elevated blood pressure were studied in the intensive care unit (ICU) in 65 patients within 4 hours following coronary artery bypass grafting (CABG). Patients with pre-existing ventricular dysfunction, bradycardia, bronchospastic disease, or postoperative complications were excluded. All patients were monitored with a thermodilution pulmonary artery catheter. Entry criteria were a systolic blood pressure (SBP) greater than 140 mm Hg or diastolic blood pressure (DBP) greater than 90 mm Hg for at least five minutes. Intravenous labetalol was loaded incrementally (5, 10, 20, and 40 mg at 10-minute intervals) to a maximum cumulative dose of 75 mg, until either SBP decreased 10% or DBP decreased 10% and was less than 90 mm Hg. Responders were entered into a 6-hour maintenance period, and received 5 to 40 mg of IV labetalol every 10 minutes as needed for blood pressure control. Hemodynamic data and temperature were recorded at baseline, just before each dose of labetalol during the loading period, and at the end of the maintenance period. Alternative therapy was given in the case of nonresponse or adverse events. Intravenous labetalol successfully controlled post-CABG hypertension in 55 of 65 patients (85%); of these, 46 responded to 35 mg or less. Although 28 patients required no further labetalol in the maintenance period, in the others dosage varied from 5 to 400 mg. Reductions in SBP and DBP were associated with moderate reductions in pulse pressure (SBP-DBP) and heart rate (HR). Cardiac index decreased by 18.5%, with a 12.5% decrease in stroke index and 8.1 % decrease in HR. Systemic vascular resistance did not increase significantly. Four patients (6%) developed hypotension related to IV labetalol. There was one death due to perioperative myocardial infarction, which was unrelated to labetalol use. The mechanism of action of IV labetalol in controlling hypertension after CABG surgery seems to be moderate negative inotropy and chronotropy. Its α-blocking effects seem to be important in preventing reflex vasoconstriction. This is directly opposite to the primary vasodilator effect found when IV labetalol is used to control nonsurgical hypertension. Because of these actions, labetalol should be avoided or used with caution in patients with preoperative and postoperative cardiac dysfunction. In patients with normal left ventricular function, IV labetalol appears to be a safe, effective agent in controlling post-CABG hypertension, with the added potential benefit of enhanced myocardial oxygen balance.

BACKGROUND Conventional parametric estimates to assess dose proportionality (DP) are sometimes unreliable due to outliers and/or variability from model assumptions. A confidence interval (CI)-based approach using FDA bioequivalence criteria (0.80–1.25) has been proposed to assess DP in contrast to the power-law method (Smith, et al, 2000). Evaluation of robust methods was performed to determine if they improved estimation reliability and statistical inference. METHODS Conventional methods of ordinary least squares regression (OLS) for independent data and mixed-effects procedure for longitudinal data, and robust methods including Huber's Estimation, Least Trimmed Regression (LTS) and Least Absolute Deviation Regression (L1) for independent data and the recently developed Robust Estimation Equations (REE) (Hu, et al, 2001) for longitudinal data were applied to area under the curve (AUC) data from a parallel-group study and a fixed-sequence study. Monte Carlo simulation was used to compare the power in detecting dose proportionality for different estimation approaches. RESULTS The results are shown in Table 1 and Table 2. Table 1. Parallel-group design evaluated by different estimation approaches Methods Slope 90% CI: Lower limit 90% CI: Upper limit Dose proportionality (DP) Note: Acceptance interval for slope is (0.8219, 1.1781). OLS 1.1910 1.0194 1.3680 DP is suggested Huber 1.1002 0.9974 1.2030 DP is suggested LTS 1.1054 0.9895 1.2214 DP is suggested L1 1.1499 1.0427 1.2573 DP is suggested Table 2. Fixed-sequence design evaluated by different estimation approaches Methods Slope 90% CI: Lower limit 90% CI: Upper limit Dose proportionality (DP) Note: Acceptance interval for slope is (0.8219, 1.1781). PROC MIXED 1.2487 1.1829 1.3145 non-DP is documented %REE Macro 1.1451 1.0714 1.2188 DP is suggested CONCLUSIONS Robust methods based on CI estimation tend to lessen the impact of outliers or other departures from normality and could improve dose proportionality assessment. Further research is ongoing to study the magnitude of the power reduction in detecting dose proportionality of conventional (power-law) estimation against robust methods. Clinical Pharmacology & Therapeutics (2005) 79, P4–P4; doi: 10.1016/j.clpt.2005.12.013

The effects of four levels of clinical pharmacy services on increasing the appropriate ordering of serum digoxin concentration (SDC) determinations for cardiothoracic surgery patients were studied. During four equivalent four-month periods from 1983 to 1986, the pharmacist on the cardiothoracic surgery service provided four different levels of clinical services: no services (Period 1), participation in ward rounds only (Period 2), participation in ward rounds supplemented by the regular provision of inservice education programs (Period 3), and participation in ward rounds only (Period 4). Explicit criteria for the appropriate monitoring of digoxin therapy were developed from published criteria and an extensive literature review; all SDC determinations that did not meet one of these criteria were deemed inappropriate. All adult patients who received digoxin therapy were included in the study; data collected for each patient included the time and amount of the daily digoxin dose and the route of administration, the time at which blood was drawn for each SDC determination, and the assay results. Data were collected through a retrospective chart review for Period 1 and concurrently thereafter. The number of appropriate SDC determinations in Period 1 were compared with the total number of appropriate SDC determinations in Periods 2, 3, and 4; Periods 2 and 4 were compared with Period 3; and Period 2 was compared with Period 4. The costs avoided as the result of decreased numbers of SDC determinations ordered were calculated as the differences between the cost of inappropriate SDC determinations in Period 1 and the costs in Periods 2, 3, and 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Eleven institutions that participated in the Coronary Artery Surgery Study (CASS) were surveyed to obtain information about the types of cardioplegic solutions used at these institutions. A short-answer questionnaire designed to obtain specific information about the composition and method of preparation of cardioplegic solutions was sent to each institution. Institutions that did not reply within four weeks were sent a second questionnaire. Nine institutions returned completed questionnaires. Four institutions used several different cardioplegic solutions, resulting in a total of 14 evaluable solutions. Six hospitals used a chemical-based cardioplegic solution, one used a blood-based solution, and two used a combination of blood and chemicals as a cardioplegic-solution base. Chloride and potassium were found in all 14 solutions, although the amounts varied widely. Dextrose was included in eight of the nine chemical-based solutions, and bicarbonate and sodium were each used in seven of the nine solutions. Centers using chemical-based cardioplegic solutions compounded them daily or froze them with a one-week expiration date; blood-based solutions had to be prepared daily. Although interinstitutional differences in dosage were evident, the cardioplegic solutions used in the institutions participating in the CASS had many similar components. Data on the composition of these solutions can be used as a guideline for developing a cardioplegic solution.

The development of a videocassette program to educate pharmacists about congestive heart failure (CHF) is described. The CHF videocassette program was developed to provide the equivalent of four hours of instruction to pharmacists in continuing-education programs or Pharm.D. degree programs. CHF was chosen as the topic because it is a common medical problem that pharmacists likely would encounter, and the material would lend itself well to visual illustration. A program-development team consisting of a pharmacist-author, an educational-design specialist, and a writer-producer was established. The group dealt first with treatment of ideas, or discussions of ways in which the educational material could best be illustrated. The pharmacist-author developed the text for the program, and the writer-producer converted the text into a script with numbered scenes. Information that could be presented more appropriately in written format was gathered into a supplemental guidebook. A storyboard script that linked the text with the audio and visual elements was developed with the help of a professional director and medical illustrator, and the program was filmed using volunteer and professional actors as well as simple animation. The program comprises two videocassettes that are 40 and 44 minutes long, respectively. The estimated cost of the production was +28,000, which includes estimates of the value of time volunteered by the pharmacist-author, educational-design specialist, nonprofessional talent, and secretaries. The program has been used for six continuing-education programs and two classes of Pharm.D. students; subjective evaluations of the program have been favorable. Videocassette technology can be applied successfully to educational programs for pharmacists.(ABSTRACT TRUNCATED AT 250 WORDS)

Summary Objective Axitinib (AG-013736), an oral, potent, and selective inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, is metabolized primarily by cytochrome P450 (CYP) 3A with minor contributions from CYP1A2, CYP2C19, and glucuronidation. Co-administration with CYP inhibitors may increase systemic exposure to axitinib and alter its safety profile. This study evaluated changes in axitinib plasma pharmacokinetic parameters and assessed safety and tolerability in healthy subjects, following axitinib co-administration with the potent CYP3A inhibitor ketoconazole. Methods In this randomized, single-blind, two-way crossover study, 32 healthy volunteers received placebo, followed by a single 5-mg oral dose of axitinib, administered either alone or on the fourth day of dosing with oral ketoconazole (400 mg/day for 7 days). Results Axitinib exposure was significantly increased in the presence of ketoconazole, with a geometric mean ratio for area under the plasma concentration–time curve from time zero to infinity of 2.06 (90% confidence interval [CI]: 1.84–2.30) and a geometric mean ratio for maximum plasma concentration (Cmax) of 1.50 (90% CI: 1.33–1.70). For axitinib alone or with ketoconazole, Cmax occurred 1.5 and 2.0 h after dosing, respectively. Adverse events were predominantly mild; the most commonly reported treatment-related adverse events were headache and nausea. Conclusions Axitinib plasma exposures and peak concentrations were increased following concurrent administration of axitinib and ketoconazole in healthy volunteers. Axitinib alone and in combination with ketoconazole was well tolerated. These findings provide an upper exposure for expected axitinib plasma concentrations in the presence of potent metabolic inhibition.

Purpose Axitinib, a potent and selective inhibitor of vascular endothelial growth factor receptors 1, 2, 3, is metabolized by cytochrome P450 3A4 and glucuronidation. This study evaluated the effect of rifampin, a potent inducer of drug-metabolizing enzymes, on axitinib plasma pharmacokinetics. Equal numbers of Japanese and Caucasian subjects were enrolled to assess the potential differences in axitinib pharmacokinetics between the two ethnicities. Methods Forty healthy volunteers were randomized to receive 5 mg axitinib alone and with 600 mg rifampin. Results Rifampin expectedly decreased AUCinf and Cmax of axitinib (geometric mean reduced by 79 and 71%, respectively). However, differences in axitinib pharmacokinetics were not observed between Japanese and Caucasian subjects (geometric mean ratios for axitinib treatment alone for AUCinf and Cmax were 103 and 96%). Conclusions The results support a common axitinib starting dose in both populations. Potent inducers of drug-metabolizing enzymes reduce axitinib exposure and dose adjustments may be needed for optimal efficacy.

The stability of nitroglycerin in intravenous admixtures was studied. Admixtures containing nitroglycerin 400 micrograms/ml and each of seven injectable drugs in concentrations used clinically were prepared in triplicate in 5% dextrose and 0.9% sodium chloride injections. Admixtures were stored in glass bottles at room temperature for 24 hours in the upright position and then for 24 hours in the inverted position to ensure contact of the solution with the rubber stopper of the container. At 0, 24, and 48 hours, samples of each admixture were assayed by high-performance liquid chromatography for nitroglycerin concentration. The pH of one randomly chosen bottle of each admixture was measured at 0, 24, and 48 hours. A significant loss of nitroglycerin potency at 48 hours was observed only in admixtures containing phenytoin; in these solutions, a 9% decrease in initial nitroglycerin concentration was noted. Phenytoin crystallization was present in all phenytoin admixtures by 24 hours. Compared with initial values, no significant differences in the pH values of any admixture samples assayed at 24 and 48 hours were noted; however, admixtures containing phenytoin had the most alkaline pH values. Under the conditions studied, nitroglycerin concentrations remained above 90% of their initial values for 48 hours in all tested admixtures; however, phenytoin crystallization limits the stability of phenytoin admixtures.