Abstract Introduction/Background Lebrikizumab (LEB) is a novel monoclonal antibody that binds with high affinity and slow off-rate to interleukin (IL)-13, thereby blocking the downstream effects of IL-13 with high potency. ADvocate1 (NCT04146363) and ADvocate2 (NCT04178967) are identically designed Phase 3 trials that evaluated LEB as a monotherapy treatment for moderate-to-severe atopic dermatitis (AD). Many patients who met the protocol-defined response criteria at Week 16, defined as achieving ≥75% improvement in the Eczema Area and Severity Index (EASI 75) or an Investigator’s Global Assessment of 0 or 1 (IGA 0/1) without use of rescue therapy, maintained a deep response up to Week 521. Deep response was defined as maintaining an IGA 0 (clear skin), a 100% improvement in the Eczema Area and Severity Index (EASI 100), or a Pruritus Numeric Rating Scale score of 0 or 1 (Pruritus NRS 0/1). Patients completing Week 52 were given the option to roll over into a long-term extension (LTE) study, ADjoin (NCT04392154), allowing the opportunity to analyze deep response for a longer period of time. This analysis supports the evolution of AD treatment goals toward maintaining higher efficacy thresholds for a longer duration. Objectives To present the long-term maintenance of LEB’s depth of response for up to 104 weeks of treatment (52 weeks in the ADvocate studies and 52 weeks in the ADjoin study). Methods Patients entering ADjoin from ADvocate1 and ADvocate2 continued taking the same LEB dose as the parent study. Patients receiving placebo (LEB withdrawal) during the maintenance period of ADvocate1 and ADvocate2 transitioned to receive LEB every 2 weeks (Q2W) during ADjoin (data not included in this analysis). The proportion of patients achieving IGA and EASI responses were calculated from the LEB-treated patients who were IGA 0/1 or EASI 75 responders, respectively, at Week 16 in ADvocate1 and ADvocate2. The proportion of patients achieving a Pruritus NRS 0/1 response were calculated from the LEB patients who were per protocol responders at Week 16 of ADvocate1 and ADvocate2. Each patient’s absolute Pruritus NRS score was calculated by averaging daily scores from the previous seven days with at least one nonmissing value. The weekly score was then rounded to the nearest integer. Consistent with common reporting practices for LTE studies, this post hoc analysis reports observed data which were analyzed regardless of rescue medication use or treatment discontinuation. Results From Week 52 to Week 104, the proportion of IGA 0 responders was maintained and slightly increased in patients treated with LEB Q2W (50.8% [N=59] to 52.3% [N=44]) and LEB every 4 weeks (Q4W; 43.5% [N=69] to 45.5% [N=55]). Greater improvements over the second year of treatment were seen in the proportion of EASI 100 responders treated with LEB Q2W (36.4% [N=88] to 39.7% [N=68]) and LEB Q4W (30.7% [N=101] to 41.3% [N=80]) as well as the proportion of Pruritus NRS 0/1 responders treated with LEB Q2W (46.3% [N=80] to 57.4% [N=61]) and Q4W (47.9% [N=94] to 55.4% [N=65]). Although rescue medication was allowed during ADjoin, a relatively low proportion of patients received ≥1 topical rescue medication in the LEB Q2W (9.8%) and LEB Q4W (15.2%) treatment arms. Conclusions These 2-year results demonstrate an extended maintenance of deep response in patients treated with LEB Q2W and LEB Q4W after responding to 16 weeks of LEB Q2W. Approximately 50% and 40% of LEB-treated patients sustained total skin clearance (IGA 0 and EASI 100, respectively) and more than 55% of LEB-treated patients reported no or minimal itch (Pruritus NRS 0/1). Maintenance treatment with LEB Q2W and LEB Q4W allows patients and providers to elevate their expected treatment goals in AD beyond EASI 75 and IGA 0/1 response.