PB0697 - To Test or Not to Test: Do all individuals with non-severe hemophilia A need DDAVP response testing?

Background: Desmopressin (DDAVP) is an effective alternative for treatment/prevention of bleeding in non-severe hemophilia A (NSHA). Due to inter-individual variability in FVIII:C rise following DDAVP administration, response testing is recommended prior to clinical use. Waiting for this can negatively impact care (including delayed/cancelled procedures). While research suggests that response testing may be unnecessary for individuals with low von Willebrand factor (0.30-0.50IU/mL), information regarding similar cut-offs in NSHA is lacking.

Aims: To identify individuals with NSHA for whom DDAVP response testing may be unnecessary.

Methods: We conducted a single-center, retrospective review of 58 adults (>18 years old) with NSHA (FVIII:C 0.01-0.50IU/ml.

Results: Most individuals were male (40/58; 70.0%) and diagnosed with mild HA (42/58; 72.4%). Within the cohort, 36/58 (62.1%) individuals had peak FVIII:C >0.5IU/mL. All 20 individuals with baseline FVIII:C >/=0.25IU/mL had peak FVIII:C levels >0.50IU/mL; 18/20 (90.0%) had peak levels >0.99IU/mL (Figure 1). Of those with baseline FVIII:C 0.06-0.24IU/mL, 16/30 (53.3%) had peak FVIII:C >0.50IU/mL (Table 1). 28 individuals with peak FVIII:C >0.50IU/mL had 4-hour levels completed; in 20/28 (71.4%), these were >0.50IU/mL. Of the 8 without sustained response, 6 (75.0%) had baseline FVIII:C 0.50IU/mL who received prophylactic DDAVP had a good clinical outcome.

Conclusion(s): Our results suggest that, among individuals with NSHA and baseline FVIII:C >/=0.25IU/mL, response testing prior to use offers no additional benefit. Rather, DDAVP response could be confirmed following the first clinical use.