Cambrian Bio reports first Phase 1b human data for ATX-304: AMPK Network Activator shifted metabolism markers without notable weight loss
Cambrian Bio has presented its first human data for ATX-304: the drug, designed to activate the cellular energy sensor AMPK, increased resting energy expenditure by 8% and shifted markers of liver fat, visceral fat, and lipid metabolism
The company presented the Phase 1b results at the American Diabetes Association. The small trial enrolled 23 adults with obesity and prediabetes: for 8 weeks they received ATX-304 or placebo, after which some moved into an open-label extension. There was almost no weight loss, so the next question is whether higher exposure can deliver a weight-loss effect while preserving muscle mass.
On 18 June, Cambrian Bio сообщила its first human data for ATX-304. AMPK is the cell's sensor of energy deficit. When a cell does not have enough available energy, AMPK switches it into acquisition mode: more glucose uptake, more fatty-acid oxidation, more mitochondrial activity. That is why AMPK has long been at the center of the dream of an "exercise mimetic," a pill that imitates training.
ATX-304 is being framed in exactly that language. Cambrian calls it the first AMPK Network Activator in clinical development: a molecule that simultaneously increases cellular fuel uptake and mitochondrial respiration. In Phase 1b, the company gave 400 mg of ATX-304 once daily to adults with obesity and prediabetes.
This is already Cambrian's second major program built around metabolic nodes of aging. In February, the company received до $30,8 млн от ARPA-H на TOR-101, a selective mTORC1 inhibitor. There, the bet was on cleaner suppression of the rapamycin axis. Here, the bet is different: turn on AMPK and mitochondria so that the body burns more energy.
For now, the result looks like an early metabolic signal. According to Cambrian's release, adiponectin increased, triglycerides fell, liver fat measured by MRI-PDFF decreased, visceral adipose tissue also decreased, and resting energy expenditure rose by 8%. Adiponectin is a hormone produced by fat tissue and linked to insulin sensitivity; triglycerides are fats in the blood. If the drug really can raise energy expenditure without overheating, tachycardia, or a broader collapse in tolerability, then it is taking a different route than GLP-1 agonists: the bet here is on energy expenditure.
That is why the release puts so much emphasis on safety. Older attempts to pharmacologically activate AMPK ran into tolerability problems. For example, in 2017 Merck showed that MK-8722 improved glucose metabolism in animals and macaques, but caused heart enlargement. In this small study, Cambrian reported no adverse findings in continuously measured body temperature or 24-hour pulse rate for ATX-304, and adverse events overall were similar to placebo. That is a good sign, but 8 weeks and 23 people do not settle the question of long-term safety.
ATX-304 already had a preclinical tail. In a mouse obesity model, the drug reduced weight while food intake was maintained; in combination with semaglutide, weight loss came from fat mass while lean body mass, which includes muscle, was preserved. In separate work in mice and kidney tubular cells, ATX-304 protected against cisplatin-induced acute kidney injury through AMPK-dependent metabolic reprogramming. All of that helps explain why Cambrian is now advancing the drug into Phase 2.
The company now has two tests ahead. REWIRE-1 is meant to assess higher exposure, lipid metabolism, and muscle function. REWIRE-2 is meant to show whether ATX-304 can actually reduce weight in people with obesity. Cambrian is trying to take an old geroscience node, AMPK, and move it through a standard clinical funnel. For now, only a small human signal has been established: energy expenditure and several metabolic markers moved in the right direction.