FEV1 recovery following methacholine challenge in asthma: Variability and comparison of methods

BACKGROUND

Methacholine challenges have been used in clinical trials to assess therapeutic effects and potential adverse reactions of interventions on pulmonary function in a sensitive population, such as in subjects with asthma. Here, we evaluate the variability of the methacholine challenge recovery model, and compare the results obtained for both incremental and bolus challenge methods.

METHODS

The extent, time course and variability of change in forced expiratory volume in 1 s (FEV₁) following repeated methacholine challenges in subjects with mild asthma were investigated in an open-label, four-period, fixed-sequence, two-method, replicate crossover study. At Visits 1 and 2, subjects underwent an incremental challenge using doubling doses of methacholine until a ≥20% decrease in FEV₁ was observed; at Visits 3 and 4, subjects underwent a bolus challenge, inhaling a single dose of methacholine calculated from the cumulative dose established during Visit 1.

RESULTS

A total of 19 subjects were included in the study. Both the mean FEV₁ area under the curve (FEV₁ AUC_0-tz) and mean maximum reductions in FEV₁ (absolute and relative) 120 min post-challenge values were higher for the incremental challenges than the bolus challenges, with no reported difference between repetitions of the same methodology. FEV₁ AUC_0-tz decrease 120 min post challenge demonstrated an intra-subject coefficient of variation (CV) of 47.2% (incremental) and 78.3% (bolus), suggesting considerable between-visit variability. The mean absolute, and similarly relative, maximum reductions in FEV₁ compared with post-diluent baseline values demonstrated lower intra-subject variability (incremental 21.16%, bolus 40.67%) than the FEV₁ AUC_0-tz-based endpoint. There was a trend towards faster recovery following the bolus challenge than with the incremental challenge. The provocative dose of methacholine inducing a ≥20% decrease in FEV₁ resulted in a between-group mean difference of 27.20% in the incremental challenge periods, with a high intra-subject CV of 80.64%, demonstrating considerable variability.

CONCLUSION

Maximum reduction in FEV₁ had the lowest variability. There was little difference between repetitions of the same methodology, as indicated by overlapping confidence intervals. There was a trend towards faster recovery following bolus challenge than with the incremental challenge. The results of this trial could be of value when designing future clinical trials using the methacholine challenge methodology.

Subthreshold grid laser versus intravitreal bevacizumab as second-line therapy for macular edema in branch retinal vein occlusion recurring after conventional grid laser treatment

PURPOSE

To compare the effects of subthreshold grid laser treatment (SGLT) and intravitreal bevacizumab injection (IVBI) for the treatment of macular edema (ME) secondary to branch retinal vein occlusion (BRVO) recurring after conventional grid laser photocoagulation.

METHODS

Thirty-five eyes were considered in this prospective, randomised, interventional study and treated with micropulse diode laser (SGLT subgroup) or IVBI (IVBI subgroup). SGLT was administered once, whereas IVBI (1.25 mg) was given at baseline and then on a pro re nata regimen according to ME presence on optical coherence tomography (OCT), performed at monthly examinations over a 12-month follow-up. Primary outcome measures were the mean BCVA changes over the follow-up and the decrease in mean central foveal thickness (CFT) on optical coherence tomography (OCT). Secondary outcomes included the proportion of eyes that gained at least 15 letters (approximately three lines) at the 12-month examination.

RESULTS

Eighteen and 17 patients were assigned to SGLT and IVBI subgroups, respectively. At baseline, the subgroups were similar with regard to mean ME duration, BCVA, and CFT. At month 12, mean CFT significantly improved from 484 μm to 271 μm in the IVBI subgroup, whereas it was unchanged in the SGLT subgroup. Mean BCVA changed from 0.92 ± 0.3 (LogMAR) to 0.99 ± 0.2 in the SGLT subgroup; in the IVBI subgroup, mean BCVA showed a statistically significant improvement from 0.94 ± 0.3 to 0.72 ± 0.2. Ten patients in the IVBI subgroup (58 %) and no patient in the SGLT subgroup gained at least three lines.

CONCLUSION

At the 1-year follow-up, IVBI provided a significant functional and anatomical improvement, whereas SGLT failed to demonstrate any beneficial effects. IVBI might be a useful approach in the treatment of recurrent ME secondary to BRVO already treated with conventional grid laser photocoagulation. UMIN registry, number UMIN000005014, URL: http://www.umin.ac.jp/ctr/index.htm.

Evidence for anti-VEGF treatment of diabetic macular edema

Diabetic macular edema (DME) is the most important cause of vision loss in patients with diabetes mellitus. Diabetic retinopathy has a remarkable impact on public health and on the quality of life of diabetic patients and thus requires special consideration. The first line of treatment remains the management of systemic risk factors but is often insufficient in controlling DME and currently, laser retinal photocoagulation is considered the standard of care. However, laser treatment reduces the risk of moderate visual loss by approximately 50% without guaranteeing remarkable effects on visual improvement. For these reasons, new strategies in the treatment of DME have been studied, in particular the use of anti-vascular endothelial growth factor (anti-VEGF) drugs. VEGF is a pluripotent growth factor that acts as a vasopermeability factor and an endothelial cell mitogen. For this reason, it represents an interesting candidate as a therapeutic target for the treatment of DME. The aim of this article is to review the evidence behind the use of anti-VEGF drugs in the treatment of DME.

Steroids as part of combination treatment: the future for the management of macular edema?

Diabetic macular edema (DME), defined as a retinal thickening involving or approaching the center of the macula, plays a major role in vision loss related to diabetic retinopathy. This article presents an in-depth analysis of therapeutic perspectives on DME by means of an approach based on combination therapy with steroids. Corticosteroid drugs have been demonstrated to both inhibit the expression of vascular endothelial growth factor (VEGF) and the VEGF gene, and to have antiinflammatory properties. A treatment algorithm is provided regarding the management of DME. While grid laser photocoagulation remains the first-line therapy for focal vasogenic DME, diffuse DME can be effectively treated by means of intravitreal injections of corticosteroids. Recalcitrant DME can also be managed beneficially with intravitreal steroids. The management of DME is complex, and often multiple treatment approaches are needed. Each form of DME should be properly classified and specifically treated. The combination treatment has still an important role in the combined treatment options for DME.

Recurrence of hemispheric retinal vein occlusion

The purpose of this article is to report a case in which a double hemispheric retinal vein occlusion (HSRVO) occurred in the same eye, involving firstly the superior half and later the inferior half of the retina. A 63-year-old woman with ill-controlled hypertension had been diagnosed with central retinal vein occlusion in the right eye in January 1998. The patient had a HSRVO of the superior hemiretina in November 2003, and a HSRVO of the inferior hemiretina in August 2005. The patient underwent a complete work-up, but the only detected risk factor was hypertension. Bearing in mind the absence of an effective treatment able to reduce both the incidence and the recurrence of retinal vein occlusion, detection and control of the risk factors, such as hypertension, is essential. We should make every effort to improve the compliance of our patients in controlling general diseases all their lives.

The effect of tiotropium on exacerbations and airflow in patients with COPD

This randomised, double-blind, parallel-group, 1-yr study compared the effect of tiotropium 18 microg once daily (n=500) and placebo (n=510) on exacerbations, associated health resource use (HRU) and airflow limitation in chronic obstructive pulmonary disease (COPD) patients. The mean+/-sd number of exacerbations during the past year was 2.14+/-1.40, the mean weekly morning peak expiratory flow (PEF) was 259.6+/-96.1 L.min-1 and the mean forced expiratory volume in one second (FEV1) was 1.37+/-0.45 L. Tiotropium significantly delayed the time to first exacerbation by approximately 100 days, reduced the proportion of patients experiencing more than one exacerbation by 17%, and decreased the number of exacerbations by 35% and exacerbation days by 37% versus placebo. Tiotropium also decreased HRU versus placebo, as indicated by the significant reductions in the use of concomitant respiratory medications, antibiotics and oral steroids, and the number of unscheduled physician contacts. Mean weekly morning PEF improved significantly with tiotropium versus placebo from week 1 until the end of the study. At the end of the study, tiotropium significantly improved trough (pre-dose) FEV1, forced vital capacity, slow vital capacity and inspiratory capacity versus placebo. In conclusion, tiotropium reduced exacerbations and associated health resource use, and improved airflow over 1 yr in chronic obstructive pulmonary disease patients.

The spectrum of iris angiography abnormalities in pseudoexfoliation syndrome

PURPOSE

To analyse the spectrum of angiographic features in patients monolaterally or bilaterally affected by pseudoexfoliation syndrome (PES), with and without glaucoma, and to evaluate the sensibility and specificity of these features in the diagnosis of glaucoma.

METHODS

Sixty-eight patients affected by PES and 20 healthy subjects underwent iris fluorescein angiography (IFA) and iris indocyanine green angiography (IICGA). Angiographic features analysed were hypoperfusion, microneovascularizations, and anastomotic vessels.

RESULTS

There was no statistically significant difference among unaffected, unilaterally affected, and bilaterally affected eyes. Patients affected by PES glaucoma showed a statistically significant difference with respect to the other groups for most of the variables. The results of qualitative variables revealed a gradual increase of the vascular involvement in the different groups. Peripupillary tufts, stromal tufts, and radial arterioles showed the best sensibility and specificity values on IFA, whereas radial arterioles and plexuses showed the highest sensibility and specificity values on IICGA. Considering all the parameters, the results were not associated with large effects on the post-test probability of disease. The values of likelihood ratio indicated that none of the examined variables was sufficiently able to discriminate patients affected by PSE glaucoma from the overall group.

CONCLUSIONS

Patients clinically affected only monolaterally by PES show microvascular changes, which are similar in both eyes. Glaucoma PES represents a more advanced stage of the disease, with more pronounced alterations, even though no typical microvascular pattern can be identified by iris angiography.

The Effect of Tiotropium on Hyperinflation and Exercise Capacity in Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, which results in the progressive development of dyspnea and exercise limitation.

OBJECTIVE AND METHODS

To compare the effect of tiotropium with placebo on forced vital capacity (FVC) in patients with moderate-to-severe COPD and lung hyperinflation, using exercise endurance, dyspnea and health-related quality of life (HRQoL) as secondary endpoints. One hundred patients were randomized to receive either tiotropium 18 mug once daily or placebo for 12 weeks.

RESULTS

Trough (predose) FVC was significantly improved with tiotropium compared to placebo on day 42 (0.27 +/- 0.08 liters) and 84 (0.20 +/- 0.08 liters; p < 0.05 for both). Trough inspiratory capacity (IC) was also significantly improved with tiotropium compared to placebo on day 42 (0.16 +/- 0.07 liters) and 84 (0.15 +/- 0.07 liters; p < 0.05 for both). Tiotropium increased the mean distance walked during the shuttle walking test by 33 +/- 12 (day 42) and 36 +/- 14 m (day 84) compared to placebo (p < 0.05 for both). On day 84, 59% of the patients in the tiotropium group and 35% of the patients in the placebo group had significant and clinically meaningful improvements in the St. George's Respiratory Questionnaire total score (p < 0.05). Numerical decreases in the focal score in the Transition Dyspnea Index in patients receiving tiotropium versus placebo suggest that tiotropium also improved dyspnea during activities of daily living.

CONCLUSION

Tiotropium 18 mug once daily reduced hyperinflation with consequent improvements in walking distance and HRQoL in patients with COPD and lung hyperinflation.

Low incidence of paradoxical bronchoconstriction in asthma and COPD patients during chronic use of Respimat soft mist inhaler

Respimat Soft Mist Inhaler (SMI) is a new-generation inhaler that offers improved lung deposition compared with chlorofluorocarbon metered dose inhalers (CFC-MDIs). Bronchodilators administered via Respimat SMI are preserved and stabilised with low concentrations of benzalkonium chloride and ethylene diamine tetra-acetic acid, both of which have been reported to cause dose-related paradoxical bronchoconstriction. The aim of this analysis was to compare the incidence of paradoxical bronchoconstriction after chronic use of bronchodilators via Respimat SMI and CFC-MDI. Data from three clinical trials, in which patients with asthma or chronic obstructive pulmonary disease (COPD) received ipratropium bromide alone or in combination with fenoterol hydrobromide, or placebo via Respimat SMI or CFC-MDI for 12 weeks, were included in the analysis. In order to evaluate the risk of paradoxical bronchoconstriction, we identified four respiratory events that might have occurred within 30 min of inhalation on four test days; these were: 'bronchospasm', 'other respiratory adverse events', 'rescue medication use' and 'asymptomatic drop in FEV(1) 15% from baseline'. In total, 631 asthma and 1538 COPD patients participated in the three studies. No occurrences of bronchospasm were reported with Respimat SMI on any test day. Overall, the incidence of respiratory events possibly indicative of paradoxical bronchoconstriction was low and similar for both devices. There was no increase in the incidence of events during 12 weeks' treatment. Delivery of bronchodilators by Respimat SMI is safe with regard to paradoxical bronchoconstriction during chronic use in patients with asthma or COPD.

Comparing measurements of retinal nerve fiber layer thickness obtained on scanning laser polarimetry with fixed and variable corneal compensator

PURPOSE

To compare retinal nerve fiber layer (RNFL) thickness measurements obtained on scanning laser polarimetry (SLP) with commercially available instruments coupled with fixed (FCC) and variable corneal compensator (VCC).

METHODS

Forty-two eyes of 42 patients underwent a complete ophthalmologic evaluation and achromatic automated perimetry (24-2 program, SITA standard strategy). Nineteen eyes were healthy (average mean deviation: -0.12 dB +/- 2.26) and 23 glaucomatous (average mean deviation: -4.92 dB +/- 6.49). All patients underwent SLP with both FCC and VCC. Adequate compensation of corneal birefringence on FCC-SLP was checked acquiring macular retardation map (MRM). RNFL thickness was evaluated considering superior and inferior maximum (SM, IM), average thickness and ellipse average (AT, EA), and superior and inferior average (SA, IA). Mean values (+/-SD) for each parameter measured by the two polarimeters were compared and linear regression calculated. The ability of each parameter to discriminate between normal and glaucomatous eyes was evaluated on both polarimeters calculating area under ROC curve.

RESULTS

A significant linear correlation for all parameters was noted (r range: 0.65-0.78). VCC produced slightly higher thickness values than FCC, both in normal and glaucomatous eyes. On both polarimeters, area under ROC curve for all parameters discriminated adequately healthy from glaucomatous eyes (range: 0.68-0.81).

CONCLUSIONS

In a highly comparable and selected group of normal and glaucomatous eyes, FCC-SLP and VCC-SLP showed considerable concordance in measuring peripapillary RNFL thickness, both for sectorial and global parameters. Proper corneal birefringence compensation provided separation of normal from glaucomatous eyes on both polarimeters.

Dry powder ipratropium bromide is as safe and effective as metered-dose inhaler formulation: a cumulative dose-response study in chronic obstructive pulmonary disease patients

A multi-center, open, randomized, 2-way crossover study was conducted with chronic obstructive pulmonary disease (COPD) patients to compare the safety and efficacy of cumulative doses of ipratropium bromide administered from a pressurized metered-dose inhaler (MDI) or from a breath-activated dry powder inhaler (DPI). Enrolled in the study were 39 patients with moderate to severe COPD and who showed a > or= 15% increase in baseline forced expiratory volume in the first second (FEV(1)) after 80 microg of ipratropium bromide. Thirty-six patients were evaluable for efficacy analysis, and 38 patients were included in the safety analysis group. A significant improvement in pulmonary function was observed following inhalation of cumulative doses of ipratropium bromide (from 20 to 320 microg), but no statistically significant difference was found between the 2 formulations. The dose-response curves were similar. There was no statistical difference in area-under-the-curve during the 180 min period after the last dose for any of the pulmonary function variables. Overall, effects on pulse rate, blood pressure, and QT interval on electrocardiogram were no different between the devices. Six mild adverse events occurred in 4 patients: ventricular ectopic beats on electrocardiogram at 270 min with MDI, bad taste with both MDI and DPI, slight transient increase in blood pressure in the same patient during each study day with both MDI and DPI. Two moderate adverse events occurred in 2 patients: transient ventricular ectopic beats on electrocardiograms with DPI at 270 min, moderate bronchospasm with MDI at 200 min. Patients expressed a preference for DPI, which was found to have a better acceptability and appeared to be easier to use than MDI. The new lactose powder formulation of ipratropium bromide inhaled via the breath-activated DPI is a safe and effective alternative to the chlorofluorocarbon-propelled MDI.

Improved delivery of ipratropium bromide using Respimat (a new soft mist inhaler) compared with a conventional metered dose inhaler: cumulative dose response study in patients with COPD

Respimat (RMT) is a reusable, propellant-free, soft mist inhaler (SMI), a novel device for inhalation therapy. We conducted a three-period cross-over study to evaluate the safety and efficacy of cumulative doses of ipratropium bromide inhaled from RMT (Two dose levels) or from a pressurized metered dose inhaler (MDI), in 36 patients with chronic obstructive pulmonary disease (COPD). The bronchodilator effect of ipratropium bromide was greater when administered via RMT (10 or 20 microg per puff, given double-blind within device, to total doses of 160 or 320 microg) than via MDI (20 microg per puff, total dose 320 microg). The bronchodilator effects of the 160 and 320 microg doses delivered via RMT were similar. Cumulative ipratropium bromide doses of 320 microg given via MDI or RMT and 160 microg given via RMT produced similar safety profiles. Between 45 min after the first drug inhalation and 45 min after the final dose, greater bronchodilatory effect was obtained from half the cumulative dose of ipratropium (RMT 10 microg per puff) when compared with the MDI (20 microg per puff). Therefore, ipratropium bromide delivered by RMT is as safe as, and can be more effective than, the MDI on acute administration in patients with COPD.

Comparison of the safety of drug delivery via HFA- and CFC-metered dose inhalers in CAO

The objective of this study was to compare the long-term safety of a fixed combination of fenoterol hydrobromide (50 microg) and ipratropium bromide (20 microg) delivered using a metered dose inhaler (MDI) formulated with a non-chlorinated propellant, hydrofluoroalkanel34a (HFA-MDI), with delivery using the conventional chlorofluorocarbon propellant (CFC-MDI, Berodual/Bronchodual). The study was designed according to Safety Assessment of Marketed Medicines (SAMM) guidelines, to reflect as far as possible the use of MDls under normal prescribing conditions. Two thousand and twenty-seven patients with chronic airways obstruction (CAO) were enrolled from 99 centres in France, 95 centres in Germany and 24 centres in Italy. Following a 2-week run-in period, patients were randomized on a 2:1 basis (1,348 patients to HFA-MDI, 679 patients to CFC-MDI) to receive a flexible dose regimen of the combination (2 puffs, 2-4 times a day, as prescribed by the investigator) during a 12-week open label phase. The overall incidence of adverse events was comparable between both groups. In addition, the incidence of respiratory side effects was also similar, with CAO exacerbations or bronchitis the most frequently recorded events. The safety profile of the HFA formulation was comparable to those of the marketed CFC-MDIs used in Germany and France/Italy. No clinically significant differences were detected between HFA134a or CFC driven inhalers on the switch from CFC- to HFA-MDI (2 weeks before randomisation versus 2 weeks after randomization). There was a trend for taste complaints to be reported more frequently by patients in the HFA-MDI group (0.7% before randomization versus 3.4% after randomization). This, however, was an expected finding as the HFA134a formulation does have a different taste to the CFC formulation. No difference between formulations was observed in the incidences of coughing or paradoxical bronchospasm. The incidence of falls in FEV1 >15% within 15 min following inhalation at each of the clinic visits was 1.2% for both CFC- and HFA-MDIs. In conclusion, administration of a fenoterol/ipratropium bromide combination via hydrofluoroalkane-metered dose inhaler is as safe as delivery by the currently available chlorofluorocarbon-metered dose inhaler, in an extended population of patients with CAO under normal prescribing conditions.

Influence of the behaviour pattern on the nocebo response of healthy volunteers

The occurrence of a nocebo effect after placebo administration to healthy volunteers in a Phase I trial was analysed according to their type of personality (Bortner Rating Scale). More subjects with a behaviour pattern A (competitive and aggressive) (50%) described subjective side effects of the placebo than type B subjects (17%, P = 0.03). The volunteers who had nocebo effect had a higher Bortner score (BS) than did placebo non-responsive subjects (P = 0.05). The BS was 205 for paramedical staff, 189 for medical and dentistry students, 173 for non-science students and 161 for science students (P < 0.04). The nocebo response was not statistically correlated with professional status. These results suggest that volunteer's type of personality might influence the reporting of subjective symptoms after placebo, and therefore impair the evaluation of new drugs in Phase I clinical trials.

Clinical pharmacology of nicardipine in liver transplant patients

Slow calcium channel antagonists are widely used among transplanted patients suffering from hypertension, although some of them tend to reduce hepatic blood flow. The aim of our study was to determine the pharmacological properties of nicardipine in transplanted patients with hypertension. Ten hours after liver transplantation, six patients (three men, three women) received 5 mg of intravenous nicardipine to prevent high blood pressure during intensive care. Prior to the administration and during the study (at the completion of the infusion, 3, 5, 10, 15, 20, 30, 45, and 60 min after infusion), the systemic and splanchnic parameters were measured (Swan Ganz catheter). Blood samples were drawn simultaneously from radial artery and free hepatic veins, in order to obtain the hepatic extraction of nicardipine. The hepatic extraction ratio was around 70% for the first 3 min, then decreased and remained stable thereafter, around 45%, showing a non linear first-pass metabolism pattern. Plasma hepatic clearance of nicardipine (699-850 ml/min) was close to total plasma clearance throughout the study (978 +/- 222 ml/min, from 71 to 87%) and half of the estimated hepatic plasma flow values at the same times (1467-1770 ml/min, from 44 to 51%). No statistically significant changes were observed in cardiac output and hepatic blood flow during the study, although there was a decrease in mean arterial blood pressure from 87 +/- 6 mmHg baseline level to 76 +/- 3 mmHg, 60 min after administration. Nicardipine chlorhydrate seems to be appropriate in post operative liver transplant patients when blood pressure must be decreased. Nicardipine safely lowers peripheral resistance, and does not induce changes in hepatic blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Is verapamil also a non-selective beta blocker?

Verapamil is a calcium channel blocker widely used as an antihypertensive agent, and its pharmacological effects may partly be due to some degree of beta blockade. In order to evaluate the changes occurring in beta-2 adrenoceptor density, 40 patients with mild to moderate hypertension received verapamil 240 mg (once a day) or captopril 20 mg (twice a day) during 30 days, in a double-blind randomized study, after a placebo run-in period. The lymphocytic membrane beta-2 adrenoceptor density (Bmax) was determined before the administration of active drugs and after a 15-day treatment. After a month of treatment, most patients showed a marked reduction of their diastolic blood pressure: from 98.2 +/- 3.2 mmHg to 81.2 +/- 4.0 mmHg (p < 0.05), in the verapamil group, and from 95.0 +/- 6.0 mmHg to 82.5 +/- 4.8 mmHg (p < 0.05) in the captopril group. After 15 days of treatment, verapamil induced an up-regulation of beta-2 adrenoceptors from 39.5 +/- 8.3 fmol/mg protein to 58.5 +/- 12.0 fmol/mg protein (p < 0.05), whereas the Bmax in the captopril group did not significantly change. No significant change occurred in the two dissociation constants. This up-regulation phenomenon, common among beta-2 blockers, supports the hypothesis of verapamil's beta blockade potency.