Efficacy and safety of linagliptin 2.5 mg twice daily versus 5 mg once daily in patients with type 2 diabetes inadequately controlled on metformin: a randomised, double-blind, placebo-controlled trial.

OBJECTIVE: Glycaemic control in patients with type 2 diabetes (T2DM) is often not achieved or not sustained using monotherapy such as metformin, necessitating the addition of other antihyperglycaemic agents. Linagliptin, a dipeptidyl peptidase-4 inhibitor, is licensed for 5 mg once-daily dosing. As metformin is administered twice daily, a fixed-dose combination of these compounds would require twice-daily administration of linagliptin. This study evaluated whether 2.5 mg twice-daily dosing of linagliptin has comparable efficacy and safety to 5 mg once-daily dosing when given in addition to metformin twice daily in patients with inadequate glycaemic control. METHODS: A total of 491 T2DM patients with glycated haemoglobin (HbA1c) 7.0-10.0% were randomised (5:5:1) to double-blind treatment with linagliptin 2.5 mg twice daily, 5 mg once daily or placebo, respectively, in addition to continuing metformin twice daily (≥1500 mg/day or maximally tolerated dose). The primary endpoint was change from baseline in HbA1c after 12 weeks. ClinicalTrials.gov, NCT01012037. RESULTS: Mean baseline HbA1c for all patients was 7.97%. After 12 weeks, linagliptin 2.5 mg twice daily and 5 mg once daily both significantly reduced HbA1c (placebo-adjusted changes from baseline -0.74% (95% CI -0.97, -0.52) and -0.80% (95% CI -1.02, -0.58), respectively, both p<0.0001). The treatment difference (twice daily-once daily) between the linagliptin regimens was 0.06 (95% CI -0.07, 0.19), the upper bound of which was less than the predefined noninferiority margin (0.35%). The overall incidence of adverse events with linagliptin 2.5 mg twice daily, 5 mg once daily and placebo was 43.0%, 34.8%, and 38.6% respectively. Hypoglycaemia was rare (3.1% with linagliptin 2.5 mg twice daily, 0.9% with 5 mg once daily, 2.3% with placebo) with no severe episodes. Study limitations include duration, patient population (mainly white) and absence of postprandial glucose data. CONCLUSIONS: Linagliptin 2.5 mg twice daily had non-inferior HbA1c-lowering effects after 12 weeks compared to 5 mg once daily, with comparable safety and tolerability, in T2DM patients inadequately controlled with metformin.

Experimental models for the evaluation of treatment of allergic rhinitis.

OBJECTIVE: To review the experimental models used for the clinical evaluation of treatments for allergic rhinitis. DATA SOURCES: Peer-reviewed clinical studies and review articles were selected from the PubMed database using the following relevant keywords: allergic rhinitis in combination with efficacy, wheal and flare, nasal challenge, park, cat room, or exposure unit. Regulatory guidance documents on allergic rhinitis were also included. STUDY SELECTION: The authors' knowledge of the field was used to limit references with emphasis on recent randomized and controlled studies. References of historical significance were also included. RESULTS: Traditional outpatient studies are universally accepted in the evaluation of treatment for allergic rhinitis. Experimental models provide ancillary information on efficacy at different stages of treatment development. Skin histamine and allergen challenge, as well as direct nasal challenge with histamine and allergen, are often used as early steps in assessing drug efficacy. Exposure units, park settings, and cat rooms better approximate real life by drawing on the natural mode of allergen exposure and delivering the sensitizing allergen to allergic individuals in the ambient air. Park studies make use of allergens in the outdoors, whereas cat rooms and exposure units present the sensitizing allergens indoors, with the latter providing consistent predetermined allergen levels. Exposure unit and park studies are acknowledged for the determination of onset of action and are also suited to the measurement of duration of effect and other measures of efficacy. Onset and duration of effect are 2 important pharmacodynamic properties of antihistamines and nasal corticosteroids as determined by the Allergic Rhinitis and Its Impact on Asthma and the European Academy of Allergology and Clinical Immunology workshop group. CONCLUSIONS: All challenge models serve as important instruments in the evaluation of antiallergic medications and provide additional information to complement traditional studies.

Comparative efficacy of cetirizine and fexofenadine for seasonal allergic rhinitis, 5-12 hours postdose, in the environmental exposure unit.

In a previous study, cetirizine and fexofenadine similarly relieved seasonal allergic rhinitis symptoms in the first 5 hours, but cetirizine was more effective at 21-24 hours postdose. This randomized, double-blind, placebo-controlled study compared the response to treatment between 5 and 12 hours. Eligible ragweed allergic subjects were exposed to pollen in the Environmental Exposure Unit and randomized (n = 599) to a single dose of cetirizine, 10 mg; fexofenadine, 180 mg; or placebo (2.5:2.5:1). The primary efficacy end point was the change from baseline in total symptom severity complex (TSSC) score at 12 hours postdose. TSSC score was the sum of self-rated scores (0 = absent to 3 = severe) for runny nose, sneezing, itchy nose/palate/throat, and itchy/watery eyes, recorded half-hourly. Mean baseline TSSC scores were similar: 9.2, cetirizine and fexofenadine; 8.9, placebo. Reductions in TSSC scores from baseline were 4.3 at 12 hours and 5.0 overall (i.e., average over 5-12 hours postdose) for cetirizine and 3.4 and 4.4, respectively, for fexofenadine. Cetirizine produced a 26% greater reduction in TSSC at 12 hours (p = 0.001) and 14% greater reduction in TSSC overall (p = 0.006) compared with fexofenadine. Cetirizine and fexofenadine reduced TSSC scores (p < 0.001) and individual symptoms (p < 0.05) more than placebo. However, cetirizine was more effective than fexofenadine (p < 0.05) for runny nose and sneezing (12 hours and overall), itchy/watery eyes (12 hours), and itchy nose/throat/palate (overall). Incidence of treatment-emergent adverse events and somnolence were similar among groups: cetirizine, 25.3 and 0.8%, respectively; fexofenadine, 29.6 and 0%, respectively; placebo, 35.0 and 0%, respectively. In conclusion, cetirizine produced greater relief of seasonal allergic rhinitis symptoms than fexofenadine at 12 hours postdose and over the 5- to 12-hour postdose period.

Levocetirizine: a new selective H1 receptor antagonist for use in allergic disorders.

Levocetirizine is the active R-enantiomer of cetirizine and represents a new second-generation histamine H(1) antagonist. It has a high affinity and selectivity for H(1) receptors. Comparative studies have shown evidence of superior H(1) receptor binding affinity over its racemate, cetirizine. Levocetirizine has a favorable pharmacokinetic profile; it is rapidly and extensively absorbed, minimally metabolized, and has a lower volume of distribution (V(d)) than some other second-generation antihistamines. A number of studies using the histamine-induced wheal and flare model have repeatedly demonstrated marked suppressive effects for levocetirizine. Levocetirizine has also been found to be effective in relieving symptoms of seasonal and perennial allergic rhinitis, including nasal congestion, and its side effects are minor.

Randomized double-blind comparison of cetirizine and fexofenadine after pollen challenge in the Environmental Exposure Unit: duration of effect in subjects with seasonal allergic rhinitis.

There is published evidence that cetirizine has a longer duration of effect than fexofenadine. This study compared duration of effect and other measures of efficacy of cetirizine, 10 mg; fexofenadine, 180 mg; and placebo in allergic subjects exposed to pollen in the Environmental Exposure Unit. Eligible subjects (n = 575) were exposed to ragweed pollen (day 1, 7 hours; day 2, 5 hours) and randomized in double-blind fashion to once-daily cetirizine, 10 mg; fexofenadine, 180 mg; or placebo. The total symptom severity complex (TSSC) score, the primary efficacy variable, was based on four rhinoconjunctivitis symptoms rated at 20-minute intervals. Treatment evaluation was divided into three periods: period 1 TSSC, average of 15 scores obtained 0-5 hours after the first dose; period 2 TSSC, average of 9 scores obtained 21-24 hours after the first dose; and period 3 TSSC, average of 6 scores obtained 0-2 hours after the second dose. The primary efficacy end point was the change from baseline TSSC at period 2. Baseline TSSC was the final pretreatment score on day 1 and was 9.7 for cetirizine, 9.8 for fexofenadine, and 9.7 for placebo. For the primary efficacy end point, the reduction in baseline TSSC at period 2 was greater for cetirizine (-3.6) compared with fexofenadine (-2.7; p < 0.001) and placebo (-2.0; p < 0.001), representing a 33% greater reduction for cetirizine versus fexofenadine. Cetirizine continued to reduce TSSC more than fexofenadine (-5.2 versus -4.6; p = 0.017) and placebo (-3.9; p < 0.001) (period 3). Similar efficacy was observed in period 1 for both active treatments. Treatment-related adverse events were similar in all groups with an incidence of somnolence of 1.3% for both active medications. In conclusion, cetirizine produced a 33% greater reduction in SAR symptoms over the 21- to 24-hour interval after the first dose and for 40 minutes after the second dose, indicating a superior and longer duration of effect, which is relevant because both are once-daily medications. Onset of action was comparable and both treatments were safe and well tolerated.

A comparison of the effect of diphenhydramine and desloratadine on vigilance and cognitive function during treatment of ragweed-induced allergic rhinitis.

BACKGROUND: Decrements in cognitive performance are associated with the use of sedating antihistamines. Most, but not all, second-generation antihistamines have been found to be nonsedating. OBJECTIVE: To examine the central nervous system (CNS) profile of a new second-generation antihistamine, desloratadine. METHODS: Subjects with ragweed-induced allergic rhinitis (aged 18-60 years) who demonstrated a predetermined severity of symptoms after priming with ragweed pollen in the Environmental Exposure Unit were randomized to receive a single dose of desloratadine, 5 mg; diphenhydramine, 50 mg; or placebo. A comprehensive battery of repeatable, automated neuropsychological tests was administered to subjects before treatment (symptomatic baseline) and 90 minutes after taking study medication. RESULTS: Both desloratadine (P = .04) and diphenhydramine (P < .01) alleviated the symptoms of allergic rhinitis compared with placebo, but treatment with diphenhydramine was associated with clinically meaningful decrements on all vigilance parameters (P < .05 for desloratadine-diphenhydramine contrasts). Also, subjects treated with diphenhydramine performed significantly worse than subjects given desloratadine or placebo across all cognitive domains evaluated. Most effect sizes for the mean desloratadine and diphenhydramine differences were between 0.4 and 0.8 (moderate to high). Stanford Sleepiness Scale scores also indicated significantly more somnolence with diphenhydramine vs desloratadine or placebo (P < .001). There were no significant differences on any of the cognitive parameters between subjects treated with desloratadine and those given placebo. CONCLUSIONS: Desloratadine improved ragweed-induced allergic rhinitis symptoms without adversely affecting performance. Diphenhydramine improved allergic rhinitis symptoms but caused significant decrements in vigilance and cognitive functioning. Thus, efficacy of antihistamine treatment must be balanced against the associated effects on CNS functioning.