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

BACKGROUND: The prostaglandin D(2) (PGD(2)) receptor 2 (DP(2) 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 DP(2) receptor that inhibits the binding of PGD(2) 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 FEV(1) 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. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12931-021-01904-8.