F.A. Romero

Safety of the intranasal toll-like receptor 4 agonist CRX-675 in allergic rhinitis

BACKGROUND CRX-675 is an aqueous formulation of a toll-like receptor 4 agonist and an inducer of TH1 responses. Studies in allergic dogs showed that pretreatment with CRX-675 reduced nasal congestion induced by allergen challenge. OBJECTIVE To study the safety of intranasal CRX-675 treatment in patients with seasonal allergic rhinitis. METHODS We conducted a single-center, randomized, double-blind, placebo-controlled, dose-escalating safety trial of single doses of CRX-675 given intranasally before intranasal ragweed challenges. Patients with ragweed-induced seasonal allergic rhinitis received increasing concentrations of ragweed to determine the dose that would result in a 30% reduction in nasal volume (PD30) during screening. Two weeks later, each patient was rechallenged with their assigned PD30 ragweed dose. Fourteen days later, patients were treated with either placebo (n = 16) or CRX-675 (2, 20, 100, or 200 microg intranasally, n = 12 per arm) 24 hours before a subsequent PD30 ragweed challenge. Patients were rechallenged with ragweed 14 days thereafter. RESULTS No serious or severe adverse events were reported. Most adverse events were mild (grade 1) and either were considered unrelated to CRX-675 or resolved without intervention. The adverse event profile of CRX-675-treated patients was similar to that of placebo-treated patients, and no dose-related toxic effects were observed. There was no clear trend in the ability of CRX-675 to inhibit nasal allergen challenge responses, but improvement in nasal symptom scores was observed at 100 microg. CONCLUSIONS This preliminary trial suggests that intranasally applied CRX-675 is safe at the doses tested. Appropriate dosing and timing will ultimately define its potential therapeutic role for allergies.

Time-dependent effects of inhaled corticosteroids on lung function, bronchial hyperresponsiveness, and airway inflammation in asthma.

BACKGROUND Exhaled nitric oxide (F(ENO)) and exhaled breath condensate (EBC) are noninvasive markers that directly measure airway inflammation and may potentially be useful in assessing asthma control and response to therapy. OBJECTIVE To examine the time-dependent effects of inhaled corticosteroids on F(ENO) and EBC markers concomitantly with lung function and bronchial hyperresponsiveness. METHODS Eleven steroid-naive adults with mild-to-moderate persistent asthma were treated with mometasone furoate dry powder inhaler, 400 microg/d, for 8 weeks, followed by a 4-week washout. Forced expiratory volume in 1 second (FEV1), the concentration of methacholine calculated to cause a 20% decline in FEV1 (PC20), F(ENO), EBC pH, and EBC nitrite measurements before, during, and after treatment were analyzed and compared. RESULTS The mean (SEM) FEV1 increased from 3.01 (0.13) L (82% predicted) to 3.24 (0.18) L (87% predicted) by week 8 (P < .05). The PC20 level increased from 1.28 (0.31) mg/mL to 2.99 (0.51) mg/mL by treatment week 8 (P < .05) and remained relatively stable through washout week 4 (P < .05). The F(ENO) level decreased from 31.1 (4.1) ppb to 20.6 (4.5) ppb by treatment week 1 (P < .01), remained low through treatment week 8 (P < .01), then trended back to the baseline level by washout week 1 (P < .01). The median EBC pH increased from 7.81 (interquartile range, 7.49-8.09) to 8.02 (interquartile range, 7.87-8.12) by treatment week 4, but did not achieve statistical significance. The EBC nitrite level decreased from 17.6 (1.6) microM to 9.3 (0.9) microM by treatment week 8 (P < .01), and remained low throughout washout week 4 (P < .05). There was a negative correlation between F(ENO) and PC20 (Spearman rank correlation coefficient = -0.50, P < .001). CONCLUSION The F(ENO) level responded the earliest to treatment and withdrawal of inhaled corticosteroids, whereas changes in EBC markers were delayed but more sustained.

Time-dependent inhibition of histamine-induced cutaneous responses by oral and intramuscular diphenhydramine and oral fexofenadine.

BACKGROUND Diphenhydramine is often the treatment of choice for acute urticarial or allergic reactions despite its adverse effects of sedation and impairment. Second- and third-generation histamine1-antihistamines are generally devoid of these adverse effects but are typically not used because of a perceived slower onset of action. OBJECTIVE To examine the time-dependent effects of oral fexofenadine and oral and intramuscular diphenhydramine to reduce histamine-induced wheal-and-flare responses. METHODS Eighteen healthy patients were included in a double-blind, placebo-controlled, 3-way, randomized, crossover study with oral fexofenadine (180 mg) and oral and intramuscular diphenhydramine (50 mg). Histamine-induced skin tests were performed before and more than 6 hours subsequent to dosing. The primary end point was time to induce a 50% reduction in histamine-induced flare. Secondary end points included change from baseline at each time point in wheal-and-flare responses and area under the curve at more than 6 hours for flare. RESULTS No significant differences were found in the 50% inhibitory responses of histamine-induced flares among the 3 groups (P = .09). No significant differences were found among the 3 groups in change from baseline at each time point except for 30 minutes during which fexofenadine had no inhibitory effect. Area under the curve analyses for wheal-and-flare responses revealed no differences among treatments at more than 6 hours. CONCLUSION Diphenhydramine tended to work more rapidly than fexofenadine, but the differences were not statistically significant. Given the adverse effect profile of diphenhydramine, but only marginal onset of action advantage, the risk-to-benefit ratio may be more favorable for oral fexofenadine when treating an acute urticarial or allergic reaction.

Effect of interleukin 13 on bronchial hyperresponsiveness and the bronchoprotective effect of β-adrenergic bronchodilators and corticosteroids

BACKGROUND Fluticasone affects airway bronchial hyperresponsiveness (BHR) and enhances bronchodilation and bronchoprotection induced by beta-adrenergic agonists. Interleukin 13 (IL-13), however, induces BHR. OBJECTIVE To test the hypotheses that fluticasone inhibits BHR after either allergen sensitization or IL-13 administration and that fluticasone restores the bronchodilation and bronchoprotective effects of beta-agonists. METHODS The BHR to methacholine induced by IL-13 or ovalbumin was determined in BALB/c mice, and the provocation concentration of methacholine that caused an increase in enhanced pause in expiration of 200% (PC200) was calculated. We compared this response to methacholine in control mice with the response after treatment with IL-13 receptor alpha 2-IgGFc fusion protein (IL-13R alpha 2) (an IL-13 blocker), fluticasone, albuterol, salmeterol, fluticasone-albuterol, and fluticasone-salmeterol. RESULTS IL-13R alpha 2 (PC200, 17.59) completely blocks the BHR-induced effects of IL-13 (PC200, 7.28; P < .005). After IL-13 therapy (PC200, 5.90; P < .005), 1 mg/mL of albuterol (PC200, 3.38; P = .33), fluticasone (PC200, 4.59; P = .40), or fluticasone plus 50 microg/mL of salmeterol (PC200, 5.59; P = .11) showed no significant bronchoprotection. In nonsensitized mice, fluticasone plus 0.25 microg/mL of salmeterol (PC200, 25.90; P < .005) showed significantly greater bronchoprotection than did salmeterol alone (PC200, 11.08; P = .26). Fluticasone plus 0.3 mg/mL of albuterol and fluticasone plus 1 mg/mL of albuterol were significantly more protective than was fluticasone or albuterol alone in ovalbumin-sensitized mice. CONCLUSIONS The protective effects of fluticasone, beta-agonists, and fluticasone plus beta-agonists are significantly less in IL-13-treated mice than in nonsensitized or ovalbumin-sensitized mice.