Structures of the Human PGD2 Receptor CRTH2 Reveal Novel Mechanisms for Ligand Recognition.

The signaling of prostaglandin D2 (PGD2) through G-protein-coupled receptor (GPCR) CRTH2 is a major pathway in type 2 inflammation. Compelling evidence suggests the therapeutic benefits of blocking CRTH2 signaling in many inflammatory disorders. Currently, a number of CRTH2 antagonists are under clinical investigation, and one compound, fevipiprant, has advanced to phase 3 clinical trials for asthma. Here, we present the crystal structures of human CRTH2 with two antagonists, fevipiprant and CAY10471. The structures, together with docking and ligand-binding data, reveal a semi-occluded pocket covered by a well-structured amino terminus and different binding modes of chemically diverse CRTH2 antagonists. Structural analysis suggests a ligand entry port and a binding process that is facilitated by opposite charge attraction for PGD2, which differs significantly from the binding pose and binding environment of lysophospholipids and endocannabinoids, revealing a new mechanism for lipid recognition by GPCRs.

Phase 3b randomized controlled trial of fevipiprant in patients with nasal polyposis with asthma (THUNDER).

BACKGROUND: Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with asthma, particularly of late onset. Current treatment options for CRSwNP have limitations, and there is an unmet need for other safe and effective therapies. OBJECTIVE: The aim of the THUNDER study was to determine the efficacy and safety of the prostaglandin D2 receptor 2 (DP2) antagonist fevipiprant in patients with CRSwNP and concomitant asthma, measured by improvement in nasal polyp score (primary end point), nasal congestion score, Sinonasal Outcome Test 22 score, and University of Pennsylvania Smell Identification Test score. METHODS: THUNDER was a phase 3b, randomized, multicenter, double-blind, placebo-controlled, parallel-group, 16-week study of fevipiprant 150 mg or 450 mg once daily versus placebo. All patients received intranasal mometasone furoate 200 µg daily. RESULTS: Ninety-eight patients were randomly assigned to fevipiprant 150 mg (n = 32), fevipiprant 450 mg (n = 34), or placebo (n = 32). Mean (SE) change from baseline in nasal polyp score at week 16 was 0.20 (0.224) for fevipiprant 150 mg, -0.10 (0.216) for fevipiprant 450 mg, and 0.14 (0.233) for placebo. Mean treatment difference was 0.05 (95% confidence interval, -0.59, 0.70; adjusted P = .979) for fevipiprant 150 mg versus placebo and -0.25 (95% confidence interval, -0.88, 0.39; adjusted P = .656) for fevipiprant 450 mg versus placebo. There was no meaningful difference in the secondary end points for fevipiprant versus placebo. CONCLUSIONS: THUNDER provided no evidence of a role for fevipiprant in the treatment of patients with CRSwNP and asthma; future studies may establish a role for other DP2 antagonists, specifically in patients with aspirin-exacerbated respiratory disease.

Role of prostaglandin D2 receptors in the pathogenesis of abdominal aortic aneurysm formation.

Prostaglandin D2 (PGD2) released from immune cells or other cell types activates its receptors, D prostanoid receptor (DP)1 and 2 (DP1 and DP2), to promote inflammatory responses in allergic and lung diseases. Prostaglandin-mediated inflammation may also contribute to vascular diseases such as abdominal aortic aneurysm (AAA). However, the role of DP receptors in the pathogenesis of AAA has not been systematically investigated. In the present study, DP1-deficient mice and pharmacological inhibitors of either DP1 or DP2 were tested in two distinct mouse models of AAA formation: angiotensin II (AngII) infusion and calcium chloride (CaCl2) application. DP1-deficient mice [both heterozygous (DP1+/-) and homozygous (DP1-/-)] were protected against CaCl2-induced AAA formation, in conjunction with decreased matrix metallopeptidase (MMP) activity and adventitial inflammatory cell infiltration. In the AngII infusion model, DP1+/- mice, but not DP1-/- mice, exhibited reduced AAA formation. Interestingly, compensatory up-regulation of the DP2 receptor was detected in DP1-/- mice in response to AngII infusion, suggesting a potential role for DP2 receptors in AAA. Treatment with selective antagonists of DP1 (laropiprant) or DP2 (fevipiprant) protected against AAA formation, in conjunction with reduced elastin degradation and aortic inflammatory responses. In conclusion, PGD2 signaling contributes to AAA formation in mice, suggesting that antagonists of DP receptors, which have been extensively tested in allergic and lung diseases, may be promising candidates to ameliorate AAA.

Long-term safety and exploratory efficacy of fevipiprant in patients with inadequately controlled asthma: the SPIRIT randomised clinical trial.

BACKGROUND: The prostaglandin D2 (PGD2) receptor 2 (DP2 receptor) pathway is an important regulator of the inflammatory cascade in asthma, which can be stimulated by allergic or non-allergic triggers. Fevipiprant is an oral, non-steroidal, highly selective, reversible antagonist of the DP2 receptor that inhibits the binding of PGD2 and its metabolites. METHODS: SPIRIT, a 2-treatment period (52-week, double-blind and optional 104-week single-blind), randomised, placebo-controlled, multicentre, parallel-group study, assessed the long-term safety of fevipiprant (150 mg and 450 mg o.d.) added to standard of care in patients ≥ 12 years with uncontrolled asthma. Stratified block randomisation was used. Patients were randomised in an approximate ratio of 3:3:1 (fevipiprant 150 mg, fevipiprant 450 mg or placebo). Patients were either newly enrolled or had participated in a previous fevipiprant Phase 3 trial. Primary endpoints were: time-to-first treatment emergent adverse event (AE); serious AE; and AE leading to discontinuation from study treatment. Data from both treatment periods were combined for analyses. Data were collected during study site visits. RESULTS: In total, 1093 patients were randomised to receive fevipiprant 150 mg, 1085 to fevipiprant 450 mg, and 360 to placebo. Overall, 1184 patients had ≥ 52 weeks' treatment, while 163 received ≥ 104 weeks' treatment. Both doses were well tolerated, with a safety profile similar to placebo both in new patients and in those enrolled from previous studies. In exploratory analyses, reduced rates of moderate-to-severe asthma exacerbations, increased time-to-first moderate-to-severe asthma exacerbation and improved FEV1 were observed for both doses of fevipiprant versus placebo; these were without multiplicity adjustment and should be interpreted with caution. SPIRIT was terminated early, on 16 December 2019, by the Sponsor. CONCLUSIONS: In patients with uncontrolled asthma, the addition of fevipiprant had a favourable long-term safety profile. TRIAL REGISTRATION: Clinicaltrials.gov, NCT03052517, prospectively registered 23 January 2017, https://clinicaltrials.gov/ct2/show/NCT03052517 .

Prostaglandin D2 metabolites activate asthmatic patient-derived type 2 innate lymphoid cells and eosinophils via the DP2 receptor.

BACKGROUND: Prostaglandin D2 (PGD2) signaling via prostaglandin D2 receptor 2 (DP2) contributes to atopic and non-atopic asthma. Inhibiting DP2 has shown therapeutic benefit in certain subsets of asthma patients, improving eosinophilic airway inflammation. PGD2 metabolites prolong the inflammatory response in asthmatic patients via DP2 signaling. The role of PGD2 metabolites on eosinophil and ILC2 activity is not fully understood. METHODS: Eosinophils and ILC2s were isolated from peripheral blood of atopic asthmatic patients. Eosinophil shape change, ILC2 migration and IL-5/IL-13 cytokine secretion were measured after stimulation with seven PGD2 metabolites in presence or absence of the selective DP2 antagonist fevipiprant. RESULTS: Selected metabolites induced eosinophil shape change with similar nanomolar potencies except for 9α,11ß-PGF2. Maximal values in forward scatter of eosinophils were comparable between metabolites. ILC2s migrated dose-dependently in the presence of selected metabolites except for 9α,11ß-PGF2 with EC50 values ranging from 17.4 to 91.7 nM. Compared to PGD2, the absolute cell migration was enhanced in the presence of Δ12-PGD2, 15-deoxy-Δ12,14-PGD2, PGJ2, Δ12-PGJ2 and 15-deoxy-Δ12,14-PGJ2. ILC2 cytokine production was dose dependent as well but with an average sixfold reduced potency compared to cell migration (IL-5 range 108.1 to 526.9 nM, IL-13 range: 125.2 to 788.3 nM). Compared to PGD2, the absolute cytokine secretion was reduced in the presence of most metabolites. Fevipiprant dose-dependently inhibited eosinophil shape change, ILC2 migration and ILC2 cytokine secretion with (sub)-nanomolar potencies. CONCLUSION: Prostaglandin D2 metabolites initiate ILC2 migration and IL-5 and IL-13 cytokine secretion in a DP2 dependent manner. Our data indicate that metabolites may be important for in vivo eosinophil activation and ILC2 migration and to a lesser extent for ILC2 cytokine secretion.

The pharmacology of the prostaglandin D2 receptor 2 (DP2) receptor antagonist, fevipiprant.

Fevipiprant is an oral, non-steroidal, highly selective, reversible antagonist of the prostaglandin D2 (DP2) receptor. The DP2 receptor is a mediator of inflammation expressed on the membrane of key inflammatory cells, including eosinophils, Th2 cells, type 2 innate lymphoid cells, CD8+ cytotoxic T cells, basophils and monocytes, as well as airway smooth muscle and epithelial cells. The DP2 receptor pathway regulates the allergic and non-allergic asthma inflammatory cascade and is activated by the binding of prostaglandin D2. Fevipiprant is metabolised by several uridine 5'-diphospho glucuronosyltransferase enzymes to an inactive acyl-glucuronide (AG) metabolite, the only major human metabolite. Both fevipiprant and its AG metabolite are eliminated by urinary excretion; fevipiprant is also possibly cleared by biliary excretion. These parallel elimination pathways suggested a low risk of major drug-drug interactions (DDI), pharmacogenetic or ethnic variability for fevipiprant, which was supported by DDI and clinical studies of fevipiprant. Phase II clinical trials of fevipiprant showed reduction in sputum eosinophilia, as well as improvement in lung function, symptoms and quality of life in patients with asthma. While fevipiprant reached the most advanced state of development to date of an oral DP2 receptor antagonist in a worldwide Phase III clinical trial programme, the demonstrated efficacy did not support further clinical development in asthma.

Efficacy and Safety of Prostaglandin D2 Receptor 2 Antagonism with Fevipiprant for Patients with Asthma: a Systematic Review and Meta-analysis of Randomized Controlled Trials.

PURPOSE OF REVIEW: Accumulating evidence has shown that prostaglandin D2 (PGD2)-chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) pathway plays an important role in promoting eosinophilic airway inflammation in asthma. We aimed to assess the efficacy and safety of CRTH2 antagonist fevipiprant in patients with persistent asthma compared with placebo. RECENT FINDINGS: We identified eligible studies by searching PubMed, EMBASE, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov. The study was registered as CRD 42020221714 ( http://www.crd.york.ac.uk/PROSPERO ). Ten randomized controlled trials with 7902 patients met our inclusion criteria. A statistically significant benefit of fevipiprant compared with placebo was shown in improving forced expiratory volume in 1 s (MD 0.05 L, 95% CI: 0.02 to 0.07; p < 0.0001), Asthma Control Questionnaire score (MD -0.10, 95% CI: -0.16 to -0.04; p = 0.001), and Asthma Quality of Life Questionnaire score (MD 0.08, 95% CI: 0.03 to 0.13; p = 0.003). Fevipiprant decreased number of patients with at least one asthma exacerbation requiring administration of systemic corticosteroids for 3 days or more (RR 0.86, 95% CI: 0.77 to 0.97; p = 0.01). Some benefits were a little more pronounced in the high eosinophil population (with an elevated blood eosinophil count or sputum eosinophil percentage) and in the 450 mg dose group. Fevipiprant was well tolerated with no safety issues compared with placebo. Fevipiprant could safely improve asthma outcomes compared to placebo. However, most of the differences didn't reach the minimal clinically important difference (MCID), thus the clinical benefits remained to be confirmed.

New treatments for asthma: From the pathogenic role of prostaglandin D2 to the therapeutic effects of fevipiprant.

Prostaglandin D2 (PGD2) is a pleiotropic mediator, significantly involved in the pathogenesis of type 2 (T2) asthma because of its biologic actions exerted on both immune/inflammatory and airway structural cells. In particular, the pro-inflammatory and pro-remodelling effects of PGD2 are mainly mediated by stimulation of chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). This receptor is the target of the oral competitive antagonist fevipiprant, which on the basis of recent phase II studies is emerging as a potential very promising anti-asthma drug. Indeed, fevipiprant appears to be safe and effective, especially in consideration of its ability to inhibit eosinophilic bronchial inflammation and improve forced expiratory volume in one second (FEV1). Further ongoing phase III trials will definitely clarify if fevipiprant can prospectively become a valid option for an efficacious add-on treatment of moderate-to-severe T2-high asthma.

Azaindole therapeutic agents.

Azaindole structural framework is an integral part of several biologically active natural and synthetic organic molecules; and several FDA approved drugs for various diseases. In the last decade, quite a number of literature reports appeared describing the pharmacology, biological activity and therapeutic applications of a variety of azaindole molecules. This prompted the organic and medicinal chemistry community to develop novel synthetic methods for various azaindoles and test them for a bioactivity against a variety of biological targets. Herein, we have summarized the biological activity of therapeutically advanced clinical candidates and several preclinical candidate drugs that contain azaindole structural moiety.

Fevipiprant has a low risk of influencing co-medication pharmacokinetics: Impact on simvastatin and rosuvastatin in different SLCO1B1 genotypes.

Fevipiprant, a prostaglandin D2 receptor 2 antagonist, is in clinical development as a treatment for asthma. The goal of this study was to assess the potential of fevipiprant to cause drug-drug interactions (DDI) as a perpetrator, that is, by altering the pharmacokinetics (PK) of co-medications. In vitro drug interaction studies of clinically relevant drug metabolizing enzymes and transporters were conducted for fevipiprant and its acyl glucuronide (AG) metabolite. Comparison of Ki values with unbound systemic or portal vein steady-state plasma exposure of fevipiprant and its AG metabolite revealed the potential for inhibition of organic anion transporting polypeptide 1B1 (OATP1B1) transporters (R-value of 5.99), while other targets including cytochrome P450 enzymes were not, or only marginally, inhibited. Consequently, an open-label, two-part, two-period, single-sequence clinical study assessed the effect of fevipiprant 450 mg QD on the pharmacokinetics of simvastatin 20 mg and rosuvastatin 20 mg, two statins with different dependency in OATP1B1-mediated hepatic uptake, in healthy adult volunteers. The study also assessed the pharmacogenetics of the SLCO1B1 gene, which encodes OATP1B1. Clinically, fevipiprant 450 mg QD showed a low potential for interaction and increased the peak concentrations of simvastatin acid and rosuvastatin by 2.23- and 1.87-fold, respectively, with little or no impact on total exposure. Genotype analysis confirmed that SLCO1B1 genotype influences statin pharmacokinetics to a similar extent either with or without fevipiprant co-administration. In summary, fevipiprant at 450 mg QD has only minor liabilities as a perpetrator for DDI.

Synthesis of a high specific activity methyl sulfone tritium isotopologue of fevipiprant (NVP-QAW039).

The synthesis of a triple tritiated isotopologue of the CRTh2 antagonist NVP-QAW039 (fevipiprant) with a specific activity >3 TBq/mmol is described. Key to the high specific activity is the methylation of a bench-stable dimeric disulfide precursor that is in situ reduced to the corresponding thiol monomer and methylated with [(3)H3]MeONos having per se a high specific activity. The high specific activity of the tritiated active pharmaceutical ingredient obtained by a build-up approach is discussed in the light of the specific activity usually to be expected if hydrogen tritium exchange methods were applied.

Establishing the Safe Space via Physiologically Based Biopharmaceutics Modeling. Case Study: Fevipiprant/QAW039.

Physiologically based pharmacokinetic and absorption modeling has increasingly been implemented for biopharmaceutics applications to define the safe space for drug product quality attributes such as dissolution. For fevipiprant/QAW039, simulations were performed to assess the impact of in vitro dissolution on the in vivo performance of immediate-release film-coated tablets during development and scaling up to commercial scale. A fevipiprant dissolution safe space was established using observed clinical intravenous and oral PK data from bioequivalent and non-bioequivalent formulations. Quality control dissolution profiles with tablets were used as GastroPlus™ model inputs to estimate the in vivo dissolution in the gastrointestinal tract and to simulate human exposure. The model was used to evaluate the intraluminal performance of the dosage forms and to predict the absorption rate limits for the 450 mg dose. The predictive model performance was demonstrated for various oral dosage forms (150‒500 mg), including the non-bioequivalent batches in fasted healthy adults. To define the safe space at 450 mg, simulations were performed using theoretical dissolution profiles. A specification of Q = 80% dissolved in 60 min or less for an immediate-release oral solid dosage form reflected the boundaries of the safe space. The dissolution profile of the 450 mg commercial scale batch was within a dissolution region where bioequivalence is anticipated, not near an edge of failure for dissolution, providing additional confidence to the proposed acceptance criteria. Thus, the safe space allowed for a wider than 10% dissolution difference for bioequivalent batches, superseding f2 similarity analyses.

Efficacy and Safety of Fevipiprant in Asthma: A Review and Meta-Analysis.

Fevipiprant is a non-steroidal oral prostaglandin D2 (PGD2) receptor 2 antagonist that reduces bronchial wall inflammation, possibly improving clinical outcomes in the asthmatic population. A systemic review search was conducted on PubMed, Embase, and Central Cochrane Registry. Randomized clinical trials were included with Fevipiprant as an intervention arm compared to placebo. For continuous variables, the standardized mean difference, and for discrete variables, Mantel-Haenszel Risk Ratio (MH Risk ratio) was used for analysis. Confidence interval of 95% and p-value < 0.05 was considered significant. The analysis was done using a random-effects model irrespective of heterogeneity. Heterogeneity was evaluated using the I2 statistic. A total of five articles, including seven trials, were included in the analysis. There was significant increase in post-bronchodilator forced expiratory volume in one second (FEV1) 0.249 (0.157-0.341), p<0.001 and pre-bronchodilator FEV1 0.115 (0.043 to 0.188), p=0.002. A decrease in asthma control questionnaire (ACQ) score of -0.124 (-0.187 to -0.062), p<0.001, was reported. Statistically significant asthma exacerbation reduction was reported in the high eosinophil count population with a daily dose of 450mg 0.77 relative risks (RR) (0.61-0.97). There was a positive deviation toward Fevipiprant 450mg dose for asthma reduction in the overall population, but it was not statistically significant. Fevipiprant produced a slight statistically significant reduction in asthma exacerbations in the high eosinophil count population with favorable deviation in the overall population. It significantly increased pre-and post-bronchodilator FEV1 and improved ACQ scores in treated patients. The benefits, though statistically significant, failed to translate into clinical importance.

Prostaglandin D2 receptor antagonists in allergic disorders: safety, efficacy, and future perspectives.

INTRODUCTION: Prostaglandin D2 (PGD2) is a major cyclooxygenase mediator that is synthesized by activated human mast cells and other immune cells. The biological effects of PGD2 are mediated by D-prostanoid (DP1), DP2 (CRTH2) and thromboxane prostanoid (TP) receptors that are expressed on several immune and non-immune cells involved in allergic inflammation. PGD2 exerts various proinflammatory effects relevant to the pathophysiology of allergic disorders. Several selective, orally active, DP2 receptor antagonists and a small number of DP1 receptor antagonists are being developed for the treatment of allergic disorders. AREAS COVERED: The role of DP2 and DP1 receptor antagonists in the treatment of asthma and allergic rhinitis. EXPERT OPINION: Head-to-head studies that compare DP1 antagonists with the standard treatment for allergic rhinitis are necessary to verify the role of these novel drugs as mono- or combination therapies. Further clinical trials are necessary to verify whether DP2 antagonists as monotherapies or, more likely, as add-on therapies, will be effective for the treatment of different phenotypes of adult and childhood asthma. Long-term studies are necessary to evaluate the safety of targeted anti-PGD2 treatments.

Same Target, Different Therapeutic Outcomes: The Case of CAY10471 and Fevipiprant on CRTh2 Receptor in Treatment of Allergic Rhinitis and Asthma.

OBJECTIVE: Prostaglandin 2 (PGD2) mediated signalling of Chemoattractant Receptorhomologous molecule expressed on Th2 cells (CRTh2) receptor has been implicated in the recruitment of inflammatory cells. This explains the design of highly selective compounds with innate abilities to antagonize PGD2-CRTh2 interactions and prevent pro-inflammatory allergies such as rhinitis and uncontrolled asthma. The development of PGD2-competitive CRTh2 binders; CAY10471 and Fevipiprant represent remarkable therapeutic progress even though they elicit disparate pharmacological propensities despite utilizing the same binding pocket. METHODS & RESULTS: In this study, we seek to pinpoint the underlying phenomenon associated with differential CRTh2 therapeutic inhibition by CAY10471 and Fevipiprant using membraneembedded molecular dynamics simulation. Findings revealed that the common carboxylate group of both compounds elicited strong attractive charges with active site Arg170 and Lys210. Interestingly, a distinctive feature was the steady occurrence of high-affinity salt-bridges and an Arg170-mediated pi-cation interaction with the tetrahydrocarbozole ring of CAY10471. Further investigations into the active site motions of both ligands revealed that CAY10471 was relatively more stable. Comparative binding analyses also revealed that CAY10471 exhibited higher ΔG, indicating the cruciality of the ring stabilization role mediated by Arg170. Moreover, conformational analyses revealed that the inhibitory activity of CAY10471 was more prominent on CRTh2 compared to Fevipiprant. CONCLUSIONS: These findings could further advance the strategic design of novel CRTh2 binders in the treatment of diseases related to pro-inflammatory allergies.

Fevipiprant in the treatment of asthma.

INTRODUCTION: Asthma is common and in many, particularly those with more severe disease, there remains a substantial unmet need. Success with biologics targeting eosinophilic inflammation underscore the value of treating inflammation in asthma beyond corticosteroids. Fevipiprant (QAW039) is an oral treatment for asthma. It competitively and reversibly antagonises the prostaglandin D2 receptor 2 (DP2) expressed on inflammatory and structural cells. Areas covered: We reviewed fevipiprant's mode of action and efficacy against other current and emerging pharmacological interventions for moderate-to-severe asthma. We undertook a literature review using the PubMed/Medline database, the U.S. National Library of Medicine's Clinical Trials website and from manufacturers' press releases with the search terms: 'QAW039', 'Fevipiprant', 'CRTH2 antagonists', 'DP2', 'DP1', 'monoclonal antibody', 'eosinophil' with 'asthma' plus the names of individual drugs. Three Phase 2 trials have been conducted and three Phase 3 trials (NCT02563067, NCT03052517, NCT02555683) are in progress. To date Fevipiprant's greatest success has been in targeting severe eosinophilic asthma. Expert opinion: Fevipiprant presents the possibility of a new orally active therapy for asthma. If successful in phase 3 trials it will have an enormous impact on the treatment paradigm for asthma and will potentially widen access for pre-biologic treatment to a larger population.

An evaluation of fevipiprant for the treatment of asthma: a promising new therapy?

INTRODUCTION: Asthma is a heterogeneous disease characterized by chronic airway inflammation that affects more than 230 million people worldwide. Current guidelines recommend an escalating stepwise decision model for the management of asthma. However, disease control continues to be a challenge, particularly in patients with severe asthma. Biologics have proven to be an effective add-on treatment especially in eosinophilic or type 2 airway disease. Comparatively, pre-biologics may represent a successful novel therapy. Fevipiprant (QAW039) is a selective, reversible, antagonist of the prostaglandin D2 receptor (DP2). Areas covered: The authors review the mechanism of action of fevipiprant as well as its pharmacokinetics, pharmacodynamics, tolerability, efficacy, and safety. Comparative therapies are also described. A comprehensive literature review was performed using: the PubMed central database, U.S. National Institutes of Health's National Library of Medicine database (NIH/NLM) and the NLM clinical trials database. Expert opinion: Fevipipiprant is a promising prebiologic therapy with convenient dosing, oral administration, and an acceptable safety profile. However, the spectrum of asthmatic patients that may benefit from this therapy is somehow limited to (i.e. moderate to severe eosinophilic asthma). Results from phase III clinical trials are needed to assess whether fevipiprant would lead to a reduction in exacerbation rates and perhaps broaden the target population.

Pharmacokinetics, Safety, and Tolerability of Fevipiprant (QAW039), a Novel CRTh2 Receptor Antagonist: Results From 2 Randomized, Phase 1, Placebo-Controlled Studies in Healthy Volunteers.

We evaluated the pharmacokinetics (PK), safety, and tolerability of a novel oral CRTh2 antagonist, fevipiprant (QAW039), in healthy subjects. Peak concentrations of fevipiprant in plasma were observed 1-3 hours postdosing. Concentrations declined in a multiexponential manner, followed by an apparent terminal phase (t1/2 , ∼20 hours). Steady state was achieved in 4 days with <2-fold accumulation. Elimination was partly by renal excretion (≤30% of the dose) and glucuronidation. Food had minimal impact on the PK of fevipiprant, and it was well tolerated at single and multiple oral doses up to 500 mg/day. No dose-dependent adverse events were observed, and all the events were mild or moderate in severity. Systemic concentrations were sufficiently high to achieve relevant target occupancy, considering in vitro pharmacology data. In summary, the data support further development as a once-daily oral therapy for allergic diseases.