Abstract
BACKGROUND: The one-strength injection regimen has increasingly become the mainstream paradigm for subcutaneous immunotherapy (SCIT). This study aimed to assess the safety and tolerability of an optimal accelerated scheme for SCIT using a house dust mite (HDM) product in adolescents and adults with allergic rhinitis (AR) or rhinoconjunctivitis (ARC), with or without asthma in China. METHODS: In this multicenter, open-label trial, patients were randomized to either One-strength or Standard group. The One-strength scheme included 6 injections with one-strength (5,000 TU/mL) followed by 4 injections at the maximum tolerated dose, administered without dose reduction when initiating a new vial. In contrast, the Standard regimen involved 14 injections across three strengths (50, 500 and 5,000 TU/mL), followed by 4 maintenance injections administered according to the medication instruction. Safety outcomes were determined by assessing Adverse Drug Reactions (ADRs), while tolerability was evaluated using a 5-point Likert scale. RESULTS: Overall, 211 patients were randomized, with 108 assigned to the One-strength group, and 103 to the Standard group. Among all participants, 57.3% reported ADRs, of which 95.3% were local reactions. Systemic ADRs were observed in 7.4% of patients in the One-strength group and 8.7% in the Standard group, with no significant difference between the two groups (p=0.7233). All ADRs were classified as WAO grade 1 or 2, with no grade ≥3. In both adolescent and adult subgroups, the incidence of systemic ADRs remained comparable between the two arms (p > 0.05). However, in adults, only the incidence of local ADRs in the One-strength group was significantly higher than that in the Standard group (p=0.0004). Tolerability was rated as "good" or "very good" by approximately 84% of patients and investigators in the One-strength group and 70% of the Standard group (p=0.0131 for patient rating; p=0.0142 for investigator rating). CONCLUSIONS: The One-strength scheme, consisting of 6 injections and no dose reduction when starting a new pack during the maintenance phase, is as safe and tolerable as standard SCIT regimen in adolescents and adults in China. CLINICAL TRIAL REGISTRATION: www.chictr.org.cn, identifier ChiCTR2200060194.