Mike Yee

Mike Yee inquired about the importance of analyzing subgroups (e.g., high tau vs. low tau) and the tau sub-study (using PET tau imaging) in the upcoming BIIB080 data readout, beyond the primary endpoint of CDR sum of boxes.

Answer

Priya Singhal, Head of Development, Biogen, confirmed the high importance of these analyses. She stated that the team will be looking at tau PET, fluid biomarkers, and trends in clinical data, triangulating all information. She highlighted the well-designed tau sub-study and the testing of three doses and two dosing regimens in the randomized controlled trial as crucial for comprehensive assessment.

Mike Yee questioned what would constitute a positive readout for the CMV trial, for both vaccine efficacy and secondary endpoints, and asked about the company's dialogue with regulatory bodies like the FDA and ACIP.

Answer

President Stephen Hoge defined a positive CMV result as vaccine efficacy exceeding 49.1% and noted strong secondary endpoints would demonstrate control over viral persistence, supporting its value. He affirmed that dialogues with the FDA, CBER, and ACIP remain productive and transparent, highlighting the three recent on-time product approvals as evidence of a strong working relationship.