Harbour BioMed's AI-Designed LET003 Shows Superior Obesity Treatment Potential in Preclinical Studies
Key Insights
Harbour BioMed (search)'s LET003 (search), the first ACVR2A (search)/2B-targeting antibody developed using AI platform Hu-mAtrIx™, demonstrated superior pharmacokinetic properties and enhanced fat reduction when combined with semaglutide in preclinical studies.
The combination therapy achieved 76% fat mass reduction while preserving lean mass, outperforming semaglutide monotherapy by 34.7% in fat reduction and increasing lean mass by 5.7%.
LET003 (search) achieved comparable lean mass-promoting effects at 5 mg/kg dose compared to bimagrumab at 15 mg/kg, suggesting potential for lower dosing and improved therapeutic index.
Harbour BioMed (search) has announced promising preclinical data for LET003 (search), its first AI-enabled monoclonal antibody targeting ACVR2A (search)/2B receptors for obesity treatment. The next-generation antibody, developed using the company's Hu-mAtrIx™ artificial intelligence platform, demonstrated superior pharmacokinetic characteristics and enhanced therapeutic effects when combined with semaglutide compared to existing therapies.
Superior Pharmacokinetic Profile
In comparative studies using human FcRn transgenic mouse and cynomolgus monkey models, LET003 (search) exhibited significantly slower blood clearance rates than all competing molecules tested following subcutaneous administration. This improved pharmacokinetic profile suggests the potential for comparable efficacy with longer dosing intervals or lower doses relative to competing therapies.
Enhanced Combination Therapy Effects
The most compelling results emerged from combination studies with semaglutide. In wild-type mouse obesity models, weekly subcutaneous administration of LET003 (search) (20 mg/kg) combined with semaglutide (30 nmol/kg) for three weeks produced remarkable outcomes:
- Fat mass decreased by 76.0% compared with vehicle control (P<0.0001)
- Fat reduction was 34.7% greater than semaglutide monotherapy (P<0.0001)
- Lean mass decreased by only 6.5% compared with vehicle but increased by 5.7% compared with semaglutide alone (P=0.0007)
In high-fat diet-induced obesity models using human FcRn transgenic mice, the combination therapy further demonstrated superior body composition management. The fat-to-body weight ratio decreased by 17.5% compared with vehicle (P<0.0001) and by 6.0% compared with semaglutide monotherapy (P=0.0127). Simultaneously, the lean mass-to-body weight ratio increased by 15.2% compared with vehicle (P<0.0001) and by 5.3% compared with semaglutide monotherapy (P=0.0194).
Dose-Dependent Advantages
Comparative dosing studies revealed LET003 (search)'s potential for improved therapeutic efficiency. In normal diet studies, LET003 at 5 mg/kg achieved lean mass-promoting effects comparable to bimagrumab at 15 mg/kg after three weeks of treatment. This three-fold dose advantage suggests superior pharmacological potential and potentially improved safety margins.
When compared directly with competitor molecules at equivalent 20 mg/kg doses, LET003 (search) demonstrated superior lean mass promotion, showing an 18.3% increase compared with vehicle (P<0.0001) and a 13.5% increase compared with the comparator molecule (P<0.0001).
AI-Driven Development Platform
The development of LET003 (search) leveraged Harbour BioMed (search)'s Hu-mAtrIx™ AI platform, which integrates fine-tuned large language models for sequence generation with AI classification and developability prediction models. This platform builds upon data generated from the company's proprietary Harbour Mice® platforms.
"The rapid advancement of LET003 (search) has been strongly supported by our Hu-mAtrIx™ AI platform," said Dr. Jingsong Wang, Founder, Chairman and Chief Executive Officer of Harbour BioMed (search). "We are highly encouraged by the favorable pharmacokinetic profile demonstrated by LET003 in preclinical studies, as well as its potential in fat reduction and lean mass preservation."
Targeting ACVR2A/2B Pathway
LET003 (search) targets activin receptors ACVR2A (search) and ACVR2B (search), which play critical roles in regulating muscle-fat metabolic homeostasis. The approach builds upon previous clinical success with bimagrumab, the first antibody targeting this pathway, which demonstrated positive results in combination with semaglutide for obesity treatment.
The ACVR2A (search)/2B signaling pathway represents a validated target for addressing the challenge of lean mass preservation during weight loss therapy. Extensive preclinical and clinical studies have demonstrated that combining receptor-blocking antibodies targeting ACVR2A/2B with GLP-1-based weight loss therapies can reduce body fat while effectively mitigating lean mass loss.
Dr. Wang indicated the company's intention to rapidly advance LET003 (search) into clinical development, aiming to provide obesity patients worldwide with more effective and safer treatment options. The preclinical data positions LET003 as a potential best-in-class therapy that could address current limitations in obesity treatment by simultaneously maximizing fat reduction and preserving lean muscle mass.