Cambrian Bio ATX-304 Phase 1b: metabolic markers shifted, weight did not
Cambrian Bio presented the first human Phase 1b data for ATX-304, an AMPK activator, at the American Diabetes Association conference: across 23 adults with obesity and prediabetes over 8 weeks, resting energy expenditure rose 8% and liver fat, visceral fat, and lipid markers shifted favorably, with minimal weight change.
23 people, 8 weeks, 400 mg of ATX-304 per day: resting energy expenditure rose 8% and body weight barely moved. So far this is an early metabolic signal.
AMPK is the cell's sensor of energy deficit. When a cell runs short of fuel, AMPK ramps up glucose uptake, fatty-acid oxidation, and mitochondrial activity. ATX-304 increases cellular fuel uptake and mitochondrial respiration simultaneously. Cambrian Bio calls it the first AMPK Network Activator in clinical development.
Cambrian presented the first human data at the American Diabetes Association (ADA) conference. The Phase 1b trial enrolled 23 adults with obesity and prediabetes: 8 weeks on 400 mg ATX-304 or placebo, after which some participants moved into an open-label extension. Adiponectin (a hormone produced by fat tissue, linked to insulin sensitivity) rose; triglycerides fell; liver fat measured by MRI-PDFF (a quantitative MRI-based fat measure) decreased; visceral fat also decreased. Resting energy expenditure rose 8%, while body weight barely changed. The metabolic markers shifted in the right direction, but the weight-loss effect remains to be demonstrated.
Cambrian reported no adverse findings in continuously measured body temperature or 24-hour pulse rate. Adverse events overall were comparable to placebo. Earlier attempts to pharmacologically activate AMPK ran into tolerability problems: in 2017, Merck showed that its activator MK-8722 improved glucose metabolism in animals and macaques but caused cardiac enlargement. The temperature and pulse data for ATX-304 look encouraging against that background, though 23 participants over 8 weeks is far too small a dataset to address long-term safety.
In preclinical mouse studies, ATX-304 reduced body weight while food intake stayed constant. In combination with semaglutide (a GLP-1 receptor agonist used for obesity), weight loss came from fat, while lean body mass, including muscle, was preserved. The company is advancing to Phase 2 with two planned trials: REWIRE-1 will assess higher drug exposure, lipid metabolism, and muscle function, while REWIRE-2 is designed to show whether ATX-304 can reduce weight in people with obesity.
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Sources
[1] cambrianbio.com
[2] t.me
Cambrian presented ATX-304's Phase 1b results at the American Diabetes Association conference, making the ADA organization page on Eternal Search the direct link between the news event and our platform. The combination of a concrete 8% energy expenditure signal and absent weight loss gives readers a clear, evidence-grounded example of the gap between moving biomarkers and demonstrating a clinical outcome.