Letter to Harry Meyer, Director of the Bureau of Biologics at the FDA, from Michael Rodell, Vice President, Regulatory Affairs and Quality Control at Hyland Therapeutics, Travenol Laboratories. Notes that Hyland Therapeutics wishes to amend the product license for Antihemophilic Factor (HUman) to allow for heat treatment. Notes that the heat treatment will involve the product being heated at 60 degrees celsius for 72 to 74 hours to reduce the transmission of hepatitis. Notes that there is an attachment to the letter which summarises test results for heated and unheated product. Notes that to determine the effectiveness of the heat treatment in eliminating the transmission of hepatitis, six chimpanzees were infused with Antihemophilic Factor (Human) which had been seeded with hepatitis B. some of these animals received the unheated version while the others received heated product. The study demonstrated that the heated treatment is capable of inactivating hepatitis B.