OBJECTIVETo investigate the characteristics of breakthrough bleeding in adult patients with severe hemophilia A (SHA) receiving low- and intermediate-dose FVIII for tertiary prophylaxis and explore the factors affecting the outcomes of the treatment.

METHODSForty-nine patients (mean age 31.53∓7.33 years) with SHA receiving tertiary prophylaxis FVIII treatment were divided into low-dose group (n=15) and intermediate-dose group (n=34). The data including clinical bleeding phenotype (Pre?AJBR), 72 h FVIII trough activity, and Functional Independence Score in Hemophilia (FISH) were recorded in all the patients, and Hemophilia Steward APP was used to record the bleeding episode and the treatment data. All the patients were followed up for at least 6 months.

RESULTSIn the low-dose and intermediate-dose groups, the number of joint bleeding (AJBR) episodes were 18.79∓13.03 and 9.28∓7.02 per year (P=0.016), and the proportions of spontaneous bleeding were 75.0% and 47.7%, respectively. The proportions of patients with target joint were 80% and 44%, target joint bleeding occurred in 59% and 41%, and cataract bleeding after 0-12 h of prophylactic injection occurred in 4.86% and 5.18% of the patients with a median breakthrough bleeding time of 40.08 h and 46.08 h (P=0.008), respectively. The proportions of patients with 72 h FVIII trough activity <1% were 44.4% and 34.8% in the two groups, respectively. AJBR was negatively correlated with the preventive dose consumed (r=-0.57, P=0.000, n=49) and FISH, but positively correlated with Pre-AJBR in the two groups (P<0.05).

CONCLUSIONTertiary prophylaxis with low- and intermediate-dose FVIII is not sufficient to achieve the goal of preventing progression of joint disease in Chinese adult patients with SHA. Although the prophylactic dose is the most important factor to affect the treatment efficacy, other non-factor approaches may also help to improve the efficacy of the treatment.