BACKGROUND: Heterogeneity in the design and quality of trials evaluating allergy immunotherapies (AITs) limits their comparability, making it difficult for physicians, patients, and payers to select the best treatment option.
METHODS: This systematic review evaluated the quality of randomised controlled trials (RCTs) of registered grass AITs using the National Institute of Health and Care Excellence checklist.
RESULTS: 17 of 44 unique RCTs (38.6%) (sample size range: 18-1,501 subjects) were subcutaneous grass immunotherapy trials and 27 (61.4%) were sublingual grass immunotherapy trials (Allergovit, 5 trials; Alutard, 8; Grazax, 13; Oralair, 6; Staloral, 8; Pollinex, 2; Phostal and Purethal, 1 each). Three trials (6.8%; all Grazax) fulfilled every quality criterion. Quality assessments revealed inconsistencies in study quality and reporting. Study quality trended towards improvement over time, particularly after 2009.
CONCLUSIONS: When as-sessing grass AIT, it is important to focus not only on endpoints but also on the quality of evidence.
