Two Phase II randomized trials on the CRTh2 antagonist AZD1981 in adults with asthma.

BACKGROUND: Chemoattractant receptor-homologous molecule expressed on T helper type 2 (Th2) cell (CRTh2) receptor antagonists is being investigated for asthma.

OBJECTIVES: The aim of this study was to assess the effects of the CRTh2 receptor antagonist, AZD1981 (with/without inhaled corticosteroids [ICSs]), on lung function and asthma control.

PATIENTS AND METHODS: Adults aged 18-60 years were enrolled in two randomized, placebo-controlled, parallel-group trials (protocol number: D9830C00003 [study 1, n=209] and protocol number: D9830C00004 [study 2, n=510]). In study 1, patients with stable asthma (forced expiratory volume in 1 second [FEV1]: 65%-110%) were withdrawn from ICS (<400 µg/d) and randomized to AZD1981 1,000 mg twice daily (bid) or placebo. In study 2, patients with uncontrolled asthma (FEV1: 40%-85%) despite ICS therapy (≥500 µg/d) were randomized to 50 mg, 400 mg, or 1,000 mg bid AZD1981 or placebo. The primary efficacy variable for both trials was the change in morning peak expiratory flow after 4 weeks of treatment. Secondary variables included Asthma Control Questionnaire (ACQ-5) scores, FEV1 assessments, safety, and tolerability. In study 2, efficacy was also assessed according to atopic status.

RESULTS: Following 4 weeks of treatment, there was a nonsignificant increase in morning peak expiratory flow on AZD1981 1,000 mg bid (9.5 L/min vs placebo, P=0.086 [study 1] and 12 L/min vs placebo, P=0.16 [study 2]). In study 2, all doses of AZD1981 provided significant improvements in ACQ-5 scores (0.26-0.3 units vs placebo, P=0.010-0.022); however, there was no dose-response relationship. Improved ACQ-5 scores and FEV1 were observed in the majority of atopic patients treated with AZD1981. AZD1981 was well tolerated across treatment groups.

CONCLUSION: Further research may be warranted in atopic patients to fully evaluate the clinical efficacy of AZD1981.