This study is about trying a new drug called eptacog beta (EB) to help people with Glanzmann Thrombasthenia (GT). GT is a rare disease where blood doesn't clot well, causing easy bleeding. Eptacog beta is not yet approved by the FDA, which is the U.S. agency that checks if a medicine is safe and works well. In the study, participants will first treat their bleeding as they usually do for 3 months. Then, they will use eptacog beta for 6 months to see if it helps stop serious bleeding. They will visit their doctor 4 to 5 times over 9 months, keep a diary of bleeding events, and have blood tests.

• Study lasts 9 months with 4 to 5 doctor visits.
• Participants try the new drug after 3 months of usual care.
• Optional phase to continue treatment for 6 more months.