Assessing Physician and Hemophilia A Patient Reasons and Expectations for Switching Treatment to Kovaltry: A Nested Study Within an Existing Registry

This observational study consists of a patient and a physician survey. This survey will
consist of questions developed by Bayer and submitted to the Steering Committee of the
existing registry, ATHN-2. Once enrolled to participate in the ATHN-2 registry and provided
consent to participate in the Bayer nested study, patients who have switched for another
product to Kovaltry within the past 50 weeks or at the time of enrollment will be prompted to
answer the additional survey questions.

Conclusion of the ATHN-2 registry is scheduled for 2021. Once data is cleaned and locked by
the registry, the data will be delivered to Bayer for conduct of our analyses.

Hemophilia A patients who have switched treatment to treatment with KOVALTRY within the
past 50 weeks, who are enrolled the ATHN 2: Factor Switching Study, and who have consented
to participate in the KOVALTRY specific module will be included in this study.