Answer
Yes. Neutralising antibodies can make factor VIII less effective; monitoring is particularly important when treatment is new or bleeding control changes.
Sources for this answer
- ReFacto AF 250 IU powder and solvent for solution for injection in pre-filled syringe — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.