Changes in CD20 status after treatment with mosunetuzumab detected by CD20⁺PAX5⁺ dual IHC. (A) Changes in the proportion of CD20⁺PAX5⁺ cells in serial biopsy specimens collected on treatment. (B) CD20 status assessed in serial biopsy specimens collected at or after progression based on progression event. (C) Time to response in paired biopsy samples by CD20 status before mosunetuzumab or at progression; numbers in each row represent percent of CD20. Symbols indicating visits are colored black or pink to represent CD20 status at that visit: black (negative), pink (positive).