[Efficacy analysis of a novel dose-adjusting regimen for prolonged delayed injection allergen- specific immunotherapy...

Objective: To investigate the efficacy and safety of a novel dose adjustment schedule based on subcutaneous immunotherapy (SCIT) after a 16 weeks delayed injection during the maintenance period. Methods: Sixty-eight patients with allergic rhinitis (AR) who received dust mite cluster SCIT and had interrupted treatment for more than 16 weeks during the maintenance period were recruited at Beijing TongRen Hospital, from July to September 2020. They were randomly divided into the novel schedule group (n=34) and the guideline recommended schedule group (n=34). In addition, 34 patients who received dust mite SCIT at the same period were selected as the continuous treatment group (n=34). When receiving treatment again after delayed injection, the novel schedule group was injected directly with the initial dose of maintenance period (10 000 SQ), and the guideline recommended schedule group started the dosage accumulation again from the lowest dose (10 SQ), while the continuous treatment group was injected according to the original schedule. Changes in the combined symptom and medication score (CSMS) from baseline after 3 years of SCIT were used as the primary efficacy evaluation index. Local and systemic adverse events were recorded to evaluate safety. SPSS 23.0 was used for statistical analysis. Results: At the end of 3 years, CSMS in all three groups decreased significantly from baseline, and there was no significant difference in the 3-year change value of CSMS from baseline between the novel schedule group and the guideline recommended schedule group (-1.0±0.3 vs -1.3±0.4, P=0.655). There was also no significant difference in the change of CSMS between the two dose-adjusted groups and the continuous treatment groups (-0.8±0.3 vs -1.3±0.3, P=0.156). No systemic adverse events occurred between the novel schedule group and the guideline recommended schedule group after restarting treatment, and there was no significant difference in frequency of adverse events (0.5% vs 0.5%, P=0.698). Conclusion: There is no significant difference in efficacy and safety between the novel dose adjustment schedule and the recommended dose adjustment schedule when SCIT interrupted injection for more than 16 weeks. Furthermore, SCIT discontinuation of injection for more than 16 weeks doesn't significantly impact on 3-year efficacy.