Background: A poorly defined jawline and blunting of the submental angle by excess submental fat (SMF) contribute to the loss of jawline contour. The injectable adipocytolytic agent ATX-101 reduces SMF, and the hyaluronic acid filler VYC-20L restores facial volume in the chin and jaw. 

Objectives: The objective of this study was to evaluate the benefits of ATX-101 followed by VYC-20L for improving overall jawline contour and definition. 

Methods: In this Phase 4, prospective, open-label, multicenter trial, participants received 1 to 6 ATX-101 treatments (8 weeks apart), followed by VYC-20L with optional VYC-20L touch-up after 14 days. The primary endpoint was Allergan Loss of Jawline Definition Scale (ALJDS) responder rate (proportion achieving ≥1-point improvement from baseline in investigator-assessed ALJDS score 4 weeks after final VYC-20L treatment). Secondary and exploratory endpoints included clinician- and participant-assessed measures of jawline definition, satisfaction, skin laxity, and SMF. Treatment-emergent adverse events (TEAEs) were monitored. 

Results: Overall, 53 adults were enrolled and treated. Among 42 evaluable participants, the ALJDS responder rate was 92.9% (95% CI, 80.5- 98.5). Consistent improvement across a range of clinician- and participant-assessed scales was achieved, including improvements in SMF Rating Scale score, Submental Skin Laxity Grade, and Global Aesthetic Improvement Scale score. Improvements in FACE-Q Satisfaction with Lower Face and Jawline and Appraisal of Area Under Chin indicated high levels of patient satisfaction. All participants experienced at least 1 TEAE; the majority of TEAEs were moderate in severity. Conclusions: Sequential treatment with ATX-101 and VYC-20L may be effective for improving overall jawline contour and definition, with an acceptable safety profile.