Sequencing from breakthrough infections in the AMP trials showed that prophylactic antibody VRC01 can select for low-frequency HIV escape mutations in roughly a third of treated participants. Deep sequencing identified escape dynamics consistent with antibody pressure, while other potent antibodies such as N6 and 1-18 largely retained activity against the variants observed. The dataset matters for next-generation passive immunization strategies because it provides granular evidence of how protection can be evaded even when overall potency remains high. Developers will likely focus on combination antibody designs and monitoring strategies that detect early escape signals during real-world use.