Discussion:
Our patient’s trough FVIII activity was >10% at seven days, and higher than reported in XTEND-Kids trial5. He has experienced zero-breakthrough bleeding episodes to date, which is consistent with XTEND-Kids data that demonstrated 64% of patients with zero bleeding episodes, 82% with zero joint bleeds, and 88% with zero spontaneous bleeds5.
The challenge with initiation of ALTUVIIIO prophylaxis in a <20kg child remains the recommended prolonged infusion rate reportedly due to sucrose contained in the final formulation.4 Per the manufacturer’s recommendations, children <20 kg require each vial to be infused over six minutes compared to 2-3 minutes per vial if ≥20 kg. This presents a unique challenge for prophylactic administration for home use without a CVAD. Our case should encourage production of expanded vial size availability of ALTUVIIIO to allow for a single vial infusion over 6 minutes in <20 kg children. Consideration may also be made for the package insert to allow peripheral infusion rate as tolerated by the patient, if this is determined safe through appropriate study.