The effect of emicizumab prophylaxis on health-related outcomes in persons with haemophilia A with inhibitors

INTRODUCTION: Persons with haemophilia A (PwHA) with inhibitors to factor VIII often experience decreased health-related outcomes. In HAVEN 1 (NCT02622321), there was a statistically significant reduction in bleeding with emicizumab prophylaxis versus no prophylaxis.

AIM: Describe health-related outcomes in PwHA with inhibitors in HAVEN 1.

METHODS: PwHA with inhibitors aged ≥12 years previously on episodic bypassing agents (BPAs) were randomized to emicizumab prophylaxis (Arm A; n = 35) or no prophylaxis (Arm B; n = 18); participants previously on BPA prophylaxis received emicizumab prophylaxis (Arm C; n = 49). Health-related outcomes assessed at baseline and monthly thereafter: Haemophilia Quality of Life Questionnaire for Adults (Haem-A-QoL), Haemophilia-specific Quality of Life Questionnaire for Children Short Form (Haemo-QoL SF), EuroQol 5-Dimensions 5-Levels (EQ-5D-5L) index utility score (IUS) and visual analogue scale (EQ-VAS) and work/school days. Days hospitalized also recorded.

RESULTS: At week 25, differences (ANCOVA) in adjusted mean scores (95% confidence interval) favoured Arm A versus B for Haem-A-QoL "Total" score (14.0 [5.6, 22.5]; P = 0.002) and "Physical Health" (21.6 [7.9, 35.2]; P = 0.003); EQ-VAS (-9.7 [-17.6, -1.82]; P = 0.017); and IUS (-0.16 [-0.25, -0.07]; P = 0.001); mean scores are comparable in Arms A and C. Throughout the study, a greater proportion of participants on emicizumab prophylaxis than no prophylaxis exceeded questionnaire-specific responder thresholds. Mean proportion of missed work days and number of days hospitalized were lower with emicizumab prophylaxis than no prophylaxis.

CONCLUSIONS: In PwHA with inhibitors, emicizumab prophylaxis was associated with substantial and meaningful improvements in health-related outcomes.