Bispecific GLP-1/GLP-2 agonism in advanced type 2 diabetes: preclinical characterization and a randomized, double-blind, placebo-controlled phase I trial.
This study characterizes PG-102, a bispecific Fc fusion protein that co-activates both GLP-1 and GLP-2 receptors, combining preclinical animal work with a Phase I human trial. In db/db mice (a model of advanced type 2 diabetes with hyperglycemia and catabolic weight loss), PG-102 demonstrated superior and more sustained glycemic control compared to semaglutide or tirzepatide while preserving body weight — an effect attributed to β-cell preservation and enhanced glucose uptake rather than acute insulin stimulation. Mechanistic experiments suggested that dual receptor engagement was necessary for these benefits, with PG-102 also promoting coordinated, delayed receptor internalization compared to monospecific agents. The Phase I randomized, double-blind, placebo-controlled trial enrolled 24 adults with overweight (BMI 25–30 kg/m²) across three dose cohorts, with 18 receiving PG-102 and 6 receiving placebo. The primary endpoint was safety and tolerability. Treatment-emergent adverse events occurred in 83.3% of PG-102 participants and 66.7% of placebo participants; gastrointestinal events were mild to moderate. No serious adverse events or treatment discontinuations were reported. Limitations include the small sample size, single-center design, overweight-only population, and lack of efficacy endpoints in the human portion of the study.
Why this grade: Although the Phase I component is a randomized, double-blind, placebo-controlled trial, it enrolled only 24 participants, was designed exclusively to assess safety/tolerability (no efficacy endpoints), and was conducted in overweight adults rather than the target T2D population, providing only limited human evidence.
PG-102 is a potency-optimized bispecific Fc fusion protein targeting GLP-1 and GLP-2 receptors. In db/db mouse models of advanced diabetes characterized by uncontrolled hyperglycemia and catabolic weight loss, PG-102 achieved superior and sustained glycemic control compared with semaglutide or tirzepatide while preserving body weight, uncoupling glycemic control from catabolic weight loss. Mechanistic studies indicated that these effects were not driven by acute insulinotropic activity, but by β-cell preservation and enhanced glucose uptake. These benefits required dual GLP-1R/GLP-2R engagement, as PG-102 outperformed monospecific Fc fusion agonists or their combination and promoted coordinated receptor trafficking with delayed internalization. We conducted a randomized, double-blind, placebo-controlled multiple ascending dose phase 1 study at a single center in the Republic of Korea in adults with overweight (BMI 25-30 kg/m²). Twenty-four participants were randomized within three weekly dose cohorts (15 mg, 30 mg, and 30/60 mg; n = 6 per cohort) in a 6:2 ratio to receive PG-102 (n = 18) or placebo (n = 6). All randomized participants (PG-102 n = 18; placebo n = 6) received at least one dose and were included in the safety analysis. Safety and tolerability were predefined as the primary endpoint and assessed by treatment-emergent adverse events (TEAEs). TEAEs occurred in 5/6 (83.3%) participants in each PG-102 cohort and 4/6 (66.7%) in placebo; treatment-related AEs occurred in 5/6 (83.3%) and 3/6 (50.0%), respectively. No serious adverse events or discontinuations due to adverse events occurred. Gastrointestinal events were mild to moderate. These findings support bispecific GLP-1/GLP-2 agonism as a mechanistically distinct incretin strategy in advanced T2D. ClinicalTrials.gov identifier: NCT06309667.
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