Tezepelumab for the treatment of severe asthma: a plain language summary of the PATHWAY and NAVIGATOR studies.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of the results of 2 clinical studies that looked at a medicine called tezepelumab. Tezepelumab is approved in the United States of America (USA), the European Union (EU) and several other countries for the treatment of severe, uncontrolled asthma in people aged 12 and above. The results of these 2 studies, called PATHWAY and NAVIGATOR, formed the basis for tezepelumab's approval for use. Tezepelumab is a type of biologic treatment called an antibody. Biologics are treatments that target certain cells or proteins in the body and often in the immune system - the body's natural defence system against infections and diseases - to reduce patients' disease. It works by blocking a key first step in the body's chain reaction leading to inflammation in the airways of people with severe asthma. The clinical studies were done to learn if tezepelumab can be used to treat people with severe, uncontrolled asthma and to find out about its safety. In both studies, tezepelumab was compared to placebo. A placebo is a dummy treatment that looked like tezepelumab but did not have any medicine in it. WHAT WERE THE MAIN CONCLUSIONS REPORTED BY THE RESEARCHERS?: In both studies, tezepelumab reduced the number of severe asthma attacks that the participants had per year compared with placebo. It also increased the volume of air that the participants could breathe out in 1 second compared with placebo. Tezepelumab was well-tolerated, and a similar number of participants had health issues in the tezepelumab and placebo treatment groups. The most common health issues that the participants had during the PATHWAY study were: Worsening of asthma, common cold, headache, and inflammation of the airways. The most common health issues that the participants had during the NAVIGATOR study were: Common cold, infection of the sinuses, throat and airways, headache, worsening of asthma, and inflammation of the airways. WHAT ARE THE KEY TAKEAWAYS?: The results showed that participants who had monthly doses of tezepelumab had fewer severe asthma attacks and better lung function than those who had placebo. In both studies, the health issues that the participants had were similar between the tezepelumab and placebo treatment groups. Overall, the studies showed that tezepelumab worked in a broad population of people with severe asthma and that the study participants had an acceptable level of health issues during the studies. These results led to the approval of tezepelumab for people with severe asthma aged 12 and above in the USA, EU and other countries. Clinical Trial Registration: PATHWAY study: NCT02054130; NAVIGATOR study: NCT03347279 (ClinicalTrials.gov).

Long-term safety and efficacy of tezepelumab in people with severe, uncontrolled asthma (DESTINATION): a randomised, placebo-controlled extension study.

BACKGROUND: Tezepelumab is a human monoclonal antibody that blocks thymic stromal lymphopoietin. The drug has been tested previously in the phase 3 NAVIGATOR (NCT03347279) and SOURCE (NCT03406078) studies, and was subsequently approved as a treatment for severe asthma. This extension study recruited from NAVIGATOR and SOURCE and aimed to evaluate the long-term safety and efficacy of tezepelumab in individuals with severe, uncontrolled asthma. METHODS: DESTINATION was a phase 3, multicentre, randomised, double-blind, placebo-controlled, long-term extension study. The study was done across 182 sites (including hospitals, clinics, medical centres, clinical trial centres, and private practices) in 18 countries. Participants (aged 12-80 years) were required to have good treatment compliance in the parent study. Randomisation was stratified by the parent study and all participants were re-randomised. Those who were previously randomised to receive tezepelumab in either parent study continued treatment of subcutaneous tezepelumab (210 mg every 4 weeks); those who were previously randomised to receive placebo in either parent study were re-randomised 1:1 to receive either subcutaneous tezepelumab (210 mg every 4 weeks) or placebo (every 4 weeks) using a randomisation list prepared by a computerised system. Total treatment duration (including the parent studies) was 104 weeks for all groups. Participants, investigators, and site staff were masked to treatment assignment. The primary endpoints were exposure-adjusted incidence of adverse events and serious adverse events and the secondary endpoint was the annualised asthma exacerbation rate; these were assessed from week 0 of the parent studies to week 104 of DESTINATION in all participants who were randomised and who received at least one dose of tezepelumab or placebo in either of the parent studies. The trial is registered with ClinicalTrials.gov, NCT03706079, and is closed to new participants. FINDINGS: Participants were recruited between Jan 7, 2019, and Oct 15, 2020. For individuals who initially received tezepelumab (n=528) in NAVIGATOR, incidence of adverse events over 104 weeks was 49·62 (95% CI 45·16 to 54·39) per 100 patient-years, compared with 62·66 (56·93 to 68·81) for those receiving placebo (n=531; difference -13·04, 95% CI -17·83 to -8·18). For serious adverse events, incidence was 7·85 (6·14 to 9·89) per 100 patient-years for individuals who initially received tezepelumab and 12·45 (9·97 to 15·35) for those who received placebo (difference -4·59, -7·69 to -1·65). In SOURCE, incidence of adverse events was 47·15 (36·06 to 60·56) per 100 patient-years for those who initially received tezepelumab (n=74) and 69·97 (54·54 to 88·40) for those who received placebo (n=76; difference -22·82, -34·77 to -10·01). For serious adverse events, incidence was 13·14 (7·65 to 21·04) per 100 patient-years for those who initially received tezepelumab and 17·99 (10·66 to 28·44) for those who received placebo (difference -4·85, -14·88 to 4·53). Tezepelumab reduced the annualised asthma exacerbation rate over 104 weeks compared with placebo. In participants initially from NAVIGATOR, the annualised asthma exacerbation rate ratio over 104 weeks was 0·42 (95% CI 0·35 to 0·51); in those initially from SOURCE, the ratio over 104 weeks was 0·61 (0·38 to 0·96). INTERPRETATION: Tezepelumab treatment was well tolerated for up to 2 years and resulted in sustained, clinically meaningful reductions in asthma exacerbations in individuals with severe, uncontrolled asthma. These findings are consistent with previous randomised, placebo-controlled studies and show the long-term safety and sustained efficacy of tezepelumab in individuals with severe, uncontrolled asthma. FUNDING: AstraZeneca and Amgen.

One-year safety and tolerability of tezepelumab in Japanese patients with severe uncontrolled asthma: results of the NOZOMI study.

OBJECTIVE: To assess the long-term safety of tezepelumab in Japanese patients with severe uncontrolled asthma. METHODS: This phase III, 52-week, open-label, single-arm study (NOZOMI, NCT04048343) evaluated the safety/tolerability of subcutaneous (SC) tezepelumab 210 mg every 4 weeks (Q4W) in Japanese patients aged 12-80 years with severe uncontrolled asthma using medium- to high-dose inhaled corticosteroids and at least one additional asthma controller medication, with/without oral corticosteroids. Exploratory outcomes included efficacy (asthma exacerbations, lung function, and asthma control), pharmacokinetic parameters, and immunogenicity. RESULTS: Among 65 patients (median age 52 years), 39 (60%) experienced 94 adverse events (AEs; predominantly nasopharyngitis [13/65]) of mild (49.2%), moderate (7.7%), or severe (3.1%) intensity. Two patients had transient injection site erythema related to tezepelumab. Four patients reported serious AEs unrelated to tezepelumab and one AE led to treatment discontinuation. AEs of special interest were infrequent and generally mild/moderate. Apart from a decrease in blood eosinophils (an expected pharmacodynamic effect), no notable trends/clinically relevant changes in hematology, clinical chemistry, or urinalysis parameters were observed. Among exploratory outcomes, tezepelumab was associated with a low annualized asthma exacerbation rate over the study period (0.11/patient-year), improved lung function (mean [standard deviation] change from baseline of 0.075 [0.226] L in pre-dose/pre-bronchodilator forced expiratory volume in 1 s), and better asthma control versus baseline (responder rate: 71.4% at Week 52). CONCLUSION: Tezepelumab 210 mg SC Q4W in Japanese patients with severe uncontrolled asthma showed safety/tolerability profiles similar to international data, with low exacerbation rates and improvements in lung function and asthma control.

Evaluation of the oral corticosteroid-sparing effect of tezepelumab in adults with oral corticosteroid-dependent asthma (SOURCE): a randomised, placebo-controlled, phase 3 study.

BACKGROUND: Tezepelumab is a human monoclonal antibody that blocks the activity of thymic stromal lymphopoietin. SOURCE evaluated the oral corticosteroid-sparing effect of tezepelumab in adults with oral corticosteroid-dependent asthma. METHODS: We conducted this phase 3, multicentre, randomised, double-blind, placebo-controlled study across 60 sites in seven countries. Participants aged 18-80 years with physician-diagnosed asthma, who had been receiving medium-dose or high-dose inhaled corticosteroids and had at least one asthma exacerbation in the 12 months before screening were eligible. Patients who were receiving medium-dose inhaled corticosteroids must have had their dose increased to a high dose for at least 3 months before screening. After an oral corticosteroid optimisation phase of up to 8 weeks, participants were randomly assigned according to a computer-generated fixed block randomisation sequence to receive tezepelumab 210 mg or placebo subcutaneously every 4 weeks during a 48 week treatment period (4 week induction phase, 36 week oral corticosteroid reduction phase, and 8 week maintenance phase). Randomisation was stratified by region. Participants, investigators, and site staff were masked to treatment assignment. The primary endpoint was the categorised percentage reduction from baseline in daily oral corticosteroid dose at week 48 without the loss of asthma control. Efficacy and safety endpoints were assessed in all participants who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, NCT03406078. FINDINGS: Between March 5, 2018, and Sept 27, 2019, 150 participants were randomly assigned to receive tezepelumab 210 mg (n=74) or placebo (n=76). The cumulative odds of achieving a category of greater percentage reduction in an oral corticosteroid dose for daily maintenance at week 48 were similar with tezepelumab or placebo in the overall population (odds ratio [OR] 1·28 [95% CI 0·69-2·35], p=0·43; the primary endpoint was not met). The cumulative odds were higher with tezepelumab than with placebo in participants with baseline blood eosinophil counts of at least 150 cells per µL (2·58 [1·16-5·75]), but not in participants with counts below 150 cells per µL (0·40 [0·14-1·13]). Tezepelumab was well tolerated, with no safety concerns identified. 53 (72%) of 74 tezepelumab-assigned participants and 65 (86%) of 76 placebo-assigned participants reported an adverse event. Serious adverse events were reported in 12 (16%) participants in the tezepelumab group and 16 (21%) participants in the placebo group. INTERPRETATION: We did not observe a significant improvement in oral corticosteroid dose reduction with tezepelumab versus placebo in the overall population of this oral corticosteroid-sparing study, although an improvement was observed in participants with baseline blood eosinophil counts of at least 150 cells per µL. FUNDING: AstraZeneca and Amgen.

Tezepelumab in Adults and Adolescents with Severe, Uncontrolled Asthma.

BACKGROUND: Tezepelumab is a human monoclonal antibody that blocks thymic stromal lymphopoietin, an epithelial-cell-derived cytokine implicated in the pathogenesis of asthma. The efficacy and safety of tezepelumab in patients with severe, uncontrolled asthma require further assessment. METHODS: We conducted a phase 3, multicenter, randomized, double-blind, placebo-controlled trial. Patients (12 to 80 years of age) were randomly assigned to receive tezepelumab (210 mg) or placebo subcutaneously every 4 weeks for 52 weeks. The primary end point was the annualized rate of asthma exacerbations over a period of 52 weeks. This end point was also assessed in patients with baseline blood eosinophil counts of less than 300 cells per microliter. Secondary end points included the forced expiratory volume in 1 second (FEV1) and scores on the Asthma Control Questionnaire-6 (ACQ-6; range, 0 [no impairment] to 6 [maximum impairment]), Asthma Quality of Life Questionnaire (AQLQ; range, 1 [maximum impairment] to 7 [no impairment]), and Asthma Symptom Diary (ASD; range, 0 [no symptoms] to 4 [worst possible symptoms]). RESULTS: Overall, 1061 patients underwent randomization (529 were assigned to receive tezepelumab and 532 to receive placebo). The annualized rate of asthma exacerbations was 0.93 (95% confidence interval [CI], 0.80 to 1.07) with tezepelumab and 2.10 (95% CI, 1.84 to 2.39) with placebo (rate ratio, 0.44; 95% CI, 0.37 to 0.53; P<0.001). In patients with a blood eosinophil count of less than 300 cells per microliter, the annualized rate was 1.02 (95% CI, 0.84 to 1.23) with tezepelumab and 1.73 (95% CI, 1.46 to 2.05) with placebo (rate ratio, 0.59; 95% CI, 0.46 to 0.75; P<0.001). At week 52, improvements were greater with tezepelumab than with placebo with respect to the prebronchodilator FEV1 (0.23 vs. 0.09 liters; difference, 0.13 liters; 95% CI, 0.08 to 0.18; P<0.001) and scores on the ACQ-6 (-1.55 vs. -1.22; difference, -0.33; 95% CI, -0.46 to -0.20; P<0.001), AQLQ (1.49 vs. 1.15; difference, 0.34; 95% CI, 0.20 to 0.47; P<0.001), and ASD (-0.71 vs. -0.59; difference, -0.12; 95% CI, -0.19 to -0.04; P = 0.002). The frequencies and types of adverse events did not differ meaningfully between the two groups. CONCLUSIONS: Patients with severe, uncontrolled asthma who received tezepelumab had fewer exacerbations and better lung function, asthma control, and health-related quality of life than those who received placebo. (Funded by AstraZeneca and Amgen; NAVIGATOR ClinicalTrials.gov number, NCT03347279.).

SOURCE: a phase 3, multicentre, randomized, double-blind, placebo-controlled, parallel group trial to evaluate the efficacy and safety of tezepelumab in reducing oral corticosteroid use in adults with oral corticosteroid dependent asthma.

BACKGROUND: Many patients with severe asthma continue to experience asthma symptoms and exacerbations despite standard-of-care treatment. A substantial proportion of these patients require long-term treatment with oral corticosteroids (OCS), often at high doses, which are associated with considerable multiorgan adverse effects, including metabolic disorders, osteoporosis and adrenal insufficiency. Tezepelumab is a human monoclonal antibody that blocks the activity of the epithelial cytokine thymic stromal lymphopoietin. In the PATHWAY phase 2b study (NCT02054130), tezepelumab significantly reduced exacerbations by up to 71% in adults with severe, uncontrolled asthma. Several ongoing phase 3 trials (SOURCE, NCT03406078; NAVIGATOR, NCT03347279; DESTINATION, NCT03706079) are assessing the efficacy and safety of tezepelumab in patients with severe, uncontrolled asthma. Here, we describe the design and objectives of SOURCE, a phase 3 OCS-sparing study. METHODS: SOURCE is an ongoing phase 3, multicentre, randomized, double-blind, placebo-controlled study to evaluate the effect of tezepelumab 210 mg administered subcutaneously every 4 weeks on OCS dose reduction in adults with OCS-dependent asthma. The study comprises a 2-week screening and enrolment period, followed by an OCS optimization phase of up to 8 weeks and a 48-week treatment period, which consists of a 4-week induction phase, followed by a 36-week OCS reduction phase and an 8-week maintenance phase. The primary objective is to assess the effect of tezepelumab compared with placebo in reducing the prescribed OCS maintenance dose. The key secondary objective is to assess the effect of tezepelumab on asthma exacerbation rates. Other secondary objectives include the proportion of patients with a reduction in OCS dose (100% or 50% reduction or those receiving < 5 mg) and the effect of tezepelumab on lung function and patient-reported outcomes. CONCLUSIONS: SOURCE is evaluating the OCS-sparing potential of tezepelumab in patients with OCS-dependent asthma. SOURCE also aims to demonstrate that treatment with tezepelumab in patients with severe asthma is associated with reductions in exacerbation rates and improvements in lung function, asthma control and health-related quality of life, while reducing OCS dose. TRIAL REGISTRATION: NCT03406078 ( ClinicalTrials.gov ). Registered 23 January 2018. https://clinicaltrials.gov/ct2/show/NCT03406078.

NAVIGATOR: a phase 3 multicentre, randomized, double-blind, placebo-controlled, parallel-group trial to evaluate the efficacy and safety of tezepelumab in adults and adolescents with severe, uncontrolled asthma.

BACKGROUND: Patients with severe, uncontrolled asthma have a significant unmet need for new treatments that have broader effects on airway inflammation, and that provide greater improvements in asthma outcomes than currently approved biologics and standard-of-care therapies. Tezepelumab is a human monoclonal antibody that blocks the activity of the epithelial cytokine thymic stromal lymphopoietin. In the PATHWAY phase 2b study (NCT02054130), tezepelumab significantly reduced exacerbations by up to 71% in adults with severe, uncontrolled asthma, irrespective of baseline disease phenotype. This article reports the design and objectives of the pivotal phase 3 NAVIGATOR study. METHODS: NAVIGATOR (NCT03347279) is an ongoing randomized, double-blind, placebo-controlled trial in adults (18-80 years old) and adolescents (12-17 years old) with severe, uncontrolled asthma, who are receiving treatment with medium- or high-dose inhaled corticosteroids plus at least one additional controller medication with or without oral corticosteroids (N = 1061). The study population includes approximately equal proportions of patients with high (≥ 300 cells/µL) and low (< 300 cells/µL) blood eosinophil counts. The study comprises a 5-6-week screening period, a 52-week treatment period and a 12-week post-treatment follow-up period. All patients will receive their prescribed controller medications without change throughout the study. The primary efficacy endpoint is the annualized asthma exacerbation rate during the 52-week treatment period. Key secondary endpoints include the effect of tezepelumab on lung function, asthma control and health-related quality of life. DISCUSSION: NAVIGATOR is evaluating the effect of tezepelumab in patients with a broad range of severe asthma phenotypes at baseline, including those with low blood eosinophil counts. The target sample size for NAVIGATOR (N = 1060) was achieved, and it is the largest clinical study of tezepelumab in severe, uncontrolled asthma to date. NAVIGATOR aims to further investigate the effect of tezepelumab on exacerbations and build on observations from the phase 2b PATHWAY study, and to demonstrate further the potential of tezepelumab to provide patients with severe, uncontrolled asthma with improvements in lung function, asthma control and health-related quality of life. TRIAL REGISTRATION: NCT03347279 (ClinicalTrials.gov). Registered 20 November 2017.

Effects of the Toll-like receptor 7 (TLR7) agonist, AZD8848, on allergen-induced responses in patients with mild asthma: a double-blind, randomised, parallel-group study.

BACKGROUND: Although allergic asthma is a complex area with many interacting factors involved, the 'hygiene hypothesis' proposes that a lack of exposure to infection during childhood may polarise the immune system towards allergen-reactive Th2-type responses in genetically susceptible individuals. Toll-like receptors (TLRs) play a key role within the innate immune system and TLR7 agonists have previously been shown to up-regulate Th1 responses and down-regulate Th2 responses to allergens in murine models of allergic or chronic asthma. This study aimed to examine the efficacy and safety of the novel TRL7 agonist AZD8848, which has been developed as an antedrug. METHODS: In this double-blind, randomised, parallel-group study, AZD8848 60 µg or placebo was administered intranasally once-weekly for 8 weeks in patients with mild-to-moderate allergic asthma (NCT00999466). Efficacy assessments were performed at 1 and 4 weeks after the last dose. The primary outcome was the late asthmatic response (LAR) fall in forced expiratory volume in 1 s (FEV1) after allergen challenge at 1-week post-treatment. RESULTS: AZD8848 significantly reduced average LAR fall in FEV1 by 27% vs. placebo at 1 week after treatment (p = 0.035). This effect was sustained at 4 weeks post-treatment; however, it did not reach clinical significance. AZD8848 reduced post-allergen challenge methacholine-induced airway hyper-responsiveness (AHR) vs. placebo at 1 week post-dosing (treatment ratio: 2.20, p = 0.024), with no effect at 4 weeks. There was no significant difference between the two groups in plasma cytokine, sputum Th2 cytokine or eosinophil responses post-allergen challenge at 1 week after treatment. The incidence of adverse events was similar in the two groups. AZD8848 was generally well tolerated. CONCLUSIONS AND CLINICAL RELEVANCE: In patients with allergic asthma, TLR7 agonists could potentially reduce allergen responsiveness by stimulating Type 1 interferon responses to down-regulate the dominant Th2 responses. TRIAL REGISTRATION: clinicaltrials.gov identifier NCT00999466.

The SYGMA programme of phase 3 trials to evaluate the efficacy and safety of budesonide/formoterol given 'as needed' in mild asthma: study protocols for two randomised controlled trials.

BACKGROUND: In many patients with mild asthma, the low frequency of symptoms and the episodic nature of exacerbations make adherence to regular maintenance treatment difficult. This often leads to over-reliance on short-acting ß2-agonist (SABA) reliever medication and under-treatment of the underlying inflammation, with poor control of asthma symptoms and increased risk of exacerbations. The use of budesonide/formoterol 'as needed' in response to symptoms may represent an alternative treatment option for patients with mild asthma. METHODS/DESIGN: The SYmbicort Given as needed in Mild Asthma (SYGMA) programme consists of two 52-week, double-blind, randomised, multicentre, parallel-group, phase 3 trials of patients aged 12 years and older with a clinical diagnosis of asthma for at least 6 months, who would qualify for treatment with regular inhaled corticosteroids (ICS). SYGMA1 aims to recruit 3750 patients who will be randomised to placebo twice daily (bid) plus as-needed budesonide/formoterol 160/4.5 µg, placebo bid plus as-needed terbutaline 0.4 mg, or budesonide 200 µg bid plus as-needed terbutaline 0.4 mg. The primary objective is to demonstrate the superiority of as-needed budesonide/formoterol over as-needed terbutaline for asthma control, as measured by well-controlled asthma weeks; a secondary objective is to establish the noninferiority of as-needed budesonide/formoterol versus maintenance budesonide plus as-needed terbutaline using the same outcome measure. SYGMA2 aims to recruit 4114 patients who will be randomised to placebo bid plus as-needed budesonide/formoterol 160/4.5 µg, or budesonide 200 µg bid plus as-needed terbutaline 0.4 mg. The primary objective is to demonstrate the noninferiority of as-needed budesonide/formoterol over budesonide bid plus as-needed terbutaline as measured by the annualised severe exacerbation rate. In both studies, use of all blinded study inhalers will be recorded electronically using Turbuhaler® Usage Monitors. DISCUSSION: Given the known risks of mild asthma, and known poor adherence with regular inhaled corticosteroids, the results of the SYGMA programme will help to determine the efficacy and safety of as-needed budesonide/formoterol therapy in mild asthma. Patient recruitment is complete, and completion of the phase 3 studies is planned in 2017. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT02149199 SYGMA1 and NCT02224157 SYGMA2. Registered on 16 May 2014 and 19 August 2014, respectively.

Biological effects and clinical efficacy of a topical Toll-like receptor 7 agonist in seasonal allergic rhinitis: a parallel group controlled phase IIa study.

OBJECTIVE AND DESIGN: The purpose of the study was to examine effects of pre-treatment with a Toll-like receptor 7 (TLR7) agonist (AZD8848) in allergic rhinitis and to evaluate clinical effects of two dosing regimens. SUBJECTS: The study involved 83 patients with allergic rhinitis. Data on effects of AZD8848 on symptoms were analysed with data from a previous study (n = 68) of identical double blind, parallel group design (NCT00770003). TREATMENT: The treatment involved intranasal AZD8848 20 µg three times weekly, 60 µg once weekly, or placebo for 5 weeks. METHODS: Nasal lavage and plasma were analysed for proof-of-mechanism markers. Daily nasal allergen challenges were given for 7 days, starting 24 h after the final AZD8848 dose. Symptoms were monitored after each challenge and every morning and evening. RESULTS: Markers of TLR-activation increased following AZD8848 administration (CXCL10, TNFα, IL-6, IFNγ). Symptoms recorded soon after allergen challenge were reduced up to eight days after the final dose of AZD8848. Morning and evening symptoms were also reduced, and these changes reached statistical significance for morning observations. Adverse effects were more frequent in the 20 µg three times weekly group. CONCLUSIONS: Repeated administration of AZD8848 activated TLR7 and produced IFN-induced effects. This was associated with a sustained reduction in allergen responsiveness.

Repeated intranasal TLR7 stimulation reduces allergen responsiveness in allergic rhinitis.

BACKGROUND: Interactions between Th1 and Th2 immune responses are of importance to the onset and development of allergic disorders. A Toll-like receptor 7 agonist such as AZD8848 may have potential as a treatment for allergic airway disease by skewing the immune system away from a Th2 profile. OBJECTIVE: To evaluate the efficacy and safety of intranasal AZD8848. METHODS: In a placebo-controlled single ascending dose study, AZD8848 (0.3-600 µg) was given intranasally to 48 healthy subjects and 12 patients with allergic rhinitis (NCT00688779). In a placebo-controlled repeat challenge/treatment study, AZD8848 (30 and 60 µg) was given once weekly for five weeks to 74 patients with allergic rhinitis out of season: starting 24 hours after the final dose, daily allergen challenges were given for seven days (NCT00770003). Safety, tolerability, pharmacokinetics, and biomarkers were monitored. During the allergen challenge series, nasal symptoms and lavage fluid levels of tryptase and α2-macroglobulin, reflecting mast cell activity and plasma exudation, were monitored. RESULTS: AZD8848 produced reversible blood lymphocyte reductions and dose-dependent flu-like symptoms: 30-100 µg produced consistent yet tolerable effects. Plasma interleukin-1 receptor antagonist was elevated after administration of AZD8848, reflecting interferon production secondary to TLR7 stimulation. At repeat challenge/treatment, AZD8848 reduced nasal symptoms recorded ten minutes after allergen challenge up to eight days after the final dose. Tryptase and α2-macroglobulin were also reduced by AZD8848. CONCLUSIONS: Repeated intranasal stimulation of Toll-like receptor 7 by AZD8848 was safe and produced a sustained reduction in the responsiveness to allergen in allergic rhinitis. TRIAL REGISTRATION: NCT00688779 and NCT00770003 as indicated above.