A randomized DBPC trial to determine the optimal effective and safe dose of a SLIT-birch pollen extract for the treatment of allergic rhinitis: results of a phase II study.

BACKGROUND: Sublingual immunotherapy (SLIT) is a potential efficacious and safe treatment option for patients with respiratory, IgE-mediated allergic diseases. A combined tolerability, dose-finding study with a sublingual liquid birch pollen preparation (SB) was conducted. METHODS: Two hundred and sixty-nine adults with birch-pollen-induced AR were randomized to placebo, SB: 3333, 10,000, 20,000 or 40,000 AUN/ml. Differences in symptom scores following a titrated nasal provocation test (TNPT) at baseline and after 5 months of treatment were determined. Safety, tolerability, birch-pollen-specific immunoglobulin levels and peak nasal inspiratory flow (PNIF) were also measured (all measures determined outside the birch pollen season). RESULTS: In all treatment groups, an improvement in symptom scores after treatment compared to baseline was observed, with an additional stepwise improvement in the active groups compared to placebo, which was significant in high-dose groups (P = 0.008 and P < 0.001, respectively). For this primary endpoint, a significant linear dose-response curve was observed: the higher the dose, the better the improvement observed. Likewise, active treatment resulted in an increase in PNIF and serum IgG levels compared to placebo. The highest improvements were found in the 40,000 AUN/ml group. All active dosages resulted in more adverse reactions than placebo, which were mainly mild and well-controlled. CONCLUSIONS: A multicentre trial evaluated the dose-response and tolerability of SB. All active treatment groups showed better responses than placebo for both primary and secondary parameters. The results indicate that, within the studied dose range, SB 40,000 AUN/ml is the most optimal effective and safe dose (ClinicalTrials.gov: NCT01639768).

Nasal nitric oxide: longitudinal reproducibility and the effects of a nasal allergen challenge in patients with allergic rhinitis.

BACKGROUND: Exhaled nitric oxide (eNO) is a validated noninvasive marker of airway inflammation in asthma. In patients with allergic rhinitis (AR), increased levels of nasal nitric oxide (nNO) have also been measured. However, the applicability of nNO as a marker of upper airway inflammation awaits validation. AIM: To test the longitudinal reproducibility of standardized nNO measurements in patients with AR and the effects of nasal allergen challenge. METHODS: Twenty patients with clinically stable, untreated AR participated in a combined study design. First, reproducibility of nNO was tested over 1, 7, and 14-21 days. Subsequently, the effect of nasal allergen challenge on nNO was studied in a placebo-controlled, parallel design. Nasal NO was measured with a chemoluminescence analyzer. Ten subjects randomly underwent a standardized nasal allergen challenge; 10 subjects received placebo. Response to nasal challenge was monitored by composite symptom scores. RESULTS: There was a good reproducibility of nNO up to 7 days [coefficient of variation (CV) over 1 (16.45%) and 7 days (21.5%)], decreasing over time [CV (14-21 days): 38.3%]. As compared with placebo, allergen challenge caused a significant increase in symptom scores (P < 0.001), accompanied by a decrease in nNO at 20 min postchallenge (P = 0.001). Furthermore, there was a gradual increase in nNO at 7 h, reaching significance at 24-h postallergen (P = 0.04). CONCLUSIONS: Similar to eNO in asthma, nNO is a noninvasive marker, potentially suitable to monitor upper airway inflammation following allergen-induced late response. Present data show a good reproducibility of nNO measurements, decreasing over time, probably because of subclinical seasonal influences.

The use of leukotriene receptor antagonists (LTRAs) as complementary therapy in asthma.

The cysteinyl-leukotrienes (cysLTs: LTC4, LTD4 and LTE4) have an important pathophysiological role in asthma. They are not only extremely potent bronchoconstrictors, but are also involved in the central mechanisms of the asthmatic inflammation and the subsequent remodelling of the airways. Allergen-induced bronchoconstriction as well as spontaneous exacerbations of asthma are associated with increased secretion of LTE4 in urine. This increase does not seem to be affected by high doses of inhaled or systemic corticosteroids. On the contrary, both in vivo and in vitro experiments indicate that corticosteroids to a certain degree may even upregulate the cysLTs synthesis. Moreover, inhaled medication may not get as far as the small airways, which are affected by inflammatory changes in asthma. Hence, the combination of an oral leukotriene receptor antagonist (LTRA) with an inhaled corticosteroid (ICS) seems a rational therapeutic approach to achieve a more complete control of the inflammatory mechanisms in asthma. The additive effects by combining an LTRA with an ICS have been investigated in adults as well as in children from 6-14 years of age. The addition of LTRA improves lung function, and reduces day and night time symptoms in all age groups. More importantly, the combination has also been found to decrease the exacerbation rates in all age groups. More recently, a few studies have compared the effect of additive therapy with LTRA and ICS versus long-acting beta 2-agonists (LABAs) and ICS in asthmatics. Depending on the patient and outcome parameters preselection, some studies found that addition of LABA to ICS resulted in a better lung function and a better overall disease control. Yet one--unsponsored-study, comparing the protective effects of LABA versus LTRA on inflammatory outcome parameters in asthma, found a significant protection against airway hyperresponsiveness to adenosine monophosphate (AMP), together with significant decreases in exhaled nitric oxide (NO) and sputum eosinophils following one week treatment with LTRA, whereas the initial protection by LABA on the AMP responsiveness was lost after one week, and no anti-inflammatory effects could be observed. Similar beneficial effects from LTRA therapy are expected in patients with nocturnal asthma, in whom a decreased responsiveness to corticosteroids has been demonstrated. The choice of either combination therapy has clinical implications. It seems that especially patients with a suboptimal lung function and a significant beta 2-agonist reversibility will benefit from the addition of a LABA, whereas asthmatics with mainly exercise-induced asthma, nocturnal symptoms, or a frequent worsening due to low tolerance to provocative stimuli, may mostly benefit by adding an LTRA to ICS. However, it remains to be determined which combination has the most profound effect on the inflammatory process and the structural changes in asthma.