2.4. Binding Antibodies to RTP004
At baseline, 66 of 2772 (2.4%) evaluable subjects had detectable antibody titers to RTP004. Treatment-related anti-RTP004 binding antibodies were detected in 35 (1.3%) subjects; 17 subjects had one exposure to RTP004, 3 had 2 exposures, and 15 had three exposures (Four subjects had three consecutive positive antibody titers after their third RTP004 exposure: subject #109 (all titers ≥ 1:200), and subjects #106, #110, and #132 (all titers < 1:200). Subject #133 developed persistent binding antibodies to RTP004 after their second exposure (all titers < 1:200), and subject #130 showed intermittent positivity with titers ≥ 1:200 which were present at the final assessment. Each of these subjects responded to DAXI treatment with no immune-related AEs. No subject developed binding antibodies to both daxibotulinumtoxinA and RTP004.