Recent work by several biotech firms including Philadelphia-based Spark Therapeutics could improve the lives of hemophilia sufferers like Krouse. Leveraging advances in gene therapy, these firms are working towards a permanent one-time "cure" that could cost more than $1 million. If successful, the patient's genetic code will be reprogrammed inducing the body to produce proper clotting factors on its own. The firm that does it stands to take a commanding lead over the estimated $5 billion market for hemophilia A and B care.