AlfaDAX-Derived ActRIIA/B Antibody with Semaglutide Enhances Fat Loss and Improves Weight-Loss Quality in DIO Mice
The combination of AB130-165 and semaglutide resulted in a 33.4% body weight reduction in diet-induced obese mice, suggesting a potential for improved weight management strategies.
Where it sits
this study against the rest of the semaglutide corpusSummary and findings
This study evaluated the effects of an anti-ActRIIA/B antibody (AB130-165) combined with semaglutide on body weight and composition in diet-induced obese mice. The combination therapy resulted in a 33.4% body weight reduction compared to semaglutide monotherapy, which achieved a −24.3% reduction. The study highlights the potential for improved fat loss while preserving lean mass.
Abstract
GLP-1 receptor agonists achieve weight loss but are associated with clinically significant reductions in lean mass. Activin type II receptors (ActRIIA and ActRIIB) mediate signaling of myostatin and activin A, both of which negatively regulate muscle growth, suggesting that dual blockade of these receptors may preserve or increase lean mass while promoting fat loss. In this study, we developed anti-ActRIIA/B antibodies using AI-driven platforms (AlfaDAX) and selected the lead candidate AB130-165 based on in vitro binding, functional blocking, and developability assessments. Compared with a laboratory-prepared bimagrumab analog, AB130-165 exhibited potent dual inhibition of ActRIIA/B signaling, with a 9.5-fold higher functional blocking activity against activin A-induced SMAD signaling and 1054-fold improvements in binding affinity for ActRIIA (K D = 0.204 pM), 10-fold for ActRIIB (K D = 0.243 pM), respectively. In diet-induced obese mice, combination therapy with AB130-165 and semaglutide resulted in a 33.4% body weight reduction, which was superior to semaglutide monotherapy (−24.3%) and the bimagrumab combination group (−25.5%). Moreover, the combination significantly improved body composition, reducing fat mass percentage by 77.8% ( vs . 65.0% in the bimagrumab combination group) and increasing the lean-to-body weight ratio to 67.3% ( vs . 62.3%), demonstrating superior fat loss with better preservation of lean mass. Collectively, these findings establish AB130-165 as a differentiated anti-ActRII antibody that enables high-quality weight loss, and its combination with semaglutide shows superior efficacy over bimagrumab-based regimens. With favorable developability and potential for long-acting subcutaneous administration, AB130-165 represents a promising next-generation therapeutic candidate for obesity and muscle-sparing weight management.
Background
This paper addresses the biological question of how combining an AlfaDAX-Derived ActRIIA/B antibody with Semaglutide affects fat loss in a model of diet-induced obesity. Previous studies have shown that Semaglutide can influence weight management, but the interaction with ActRIIA/B antibodies has not been thoroughly explored. Understanding these interactions could provide insights into new strategies for obesity treatment.
Methods
The study utilized a diet-induced obesity mouse model to assess the effects of the AlfaDAX-Derived ActRIIA/B antibody in combination with Semaglutide. The specific population, sample size (n), dosing regimen, and duration of treatment were not reported in the abstract. Primary and secondary outcome measures related to fat loss and weight-loss quality were evaluated.
Results
Not reported in abstract.
Interpretation
Without specific numeric findings, it is challenging to compare this study's results to prior literature or assess the clinical significance of any observed effects. The lack of reported data limits the ability to draw firm conclusions about the efficacy of the combination treatment. Potential confounds include the use of a rodent model, which may not directly translate to human outcomes.
Key findings
- Not reported in abstract.
Limitations
- Not reported in abstract.