D2.222 - A real-world observational study following the first year of SQ grass or SQ tree SLIT-tablet treatment to evaluate persistence and adherence in routine clinical practice among general practitioners in Norway

Discussions about the importance of persistence in allergen immunotherapy have grown in recent years, with both persistence and adherence studied in secondary care. However, similar data from a primary care setting is lacking. Many General Practitioners (GPs) in Norway have initiated treatment with SQ grass or SQ tree SLIT-tablet, supported by national recommendations.

The main objective was to assess the persistence with SQ grass or SQ tree SLIT-tablet during the first year of treatment in a routine clinical practice in primary care, with a threshold of 70%. Secondary objectives included evaluating patient adherence, reasons for early discontinuation, safety with SQ grass or SQ tree SLIT-tablet, allergy symptoms and medication use during pollen season, and assessing patient satisfaction throughout the initial year.

The study involved 204 patients enrolled by 17 GPs. After one year, 78% of the patients persisted treatment with SQ grass or SQ tree SLIT-tablet. Thus, the study met the primary aim of a one-year persistence above the threshold of 70%. Adherence remained high throughout, with approximately 90% of patients reporting daily SLIT-tablet intake at each visit; missed doses were mainly due to forgetfulness rather than adverse events or access issues. Allergy symptoms improved from baseline to the post-pollen season assessment, and symptomatic medication use decreased. Patient-reported outcomes indicated clinical benefit: 92% of patients and 94% of GPs expressed satisfaction or high satisfaction with the treatment. Safety data were consistent with the known safety profiles of the SLIT-tablets: 47% experienced at least one adverse event, mostly mild or moderate; no serious adverse events occurred, and 92% of events resolved. Overall, 22% of patients discontinued within the first year, primarily due to adverse events or loss to follow-up. Initiating treatment before or after the pollen season did not significantly affect persistence.

The study demonstrates the real-world results of initiations of SQ grass or SQ tree SLIT-tablet in primary care practice showing high persistence, good adherence, improved allergy control, reduced medication use, high satisfaction within the first year of treatment, and an expected safety profile - similar to outcomes seen in secondary care settings. These findings imply that GPs can effectively handle the treatment of grass and tree pollen allergic rhinoconjunctivitis with a generally high adherence/persistence, with patients motivated to continue beyond the initial months and satisfied with their treatment. Factors such as regular follow-up, clear guidance, and setting realistic expectations likely contributed to these positive outcomes.

These results support increased use of SLIT-tablets in general practice.