Exploratory extracellular vesicle biomarkers suggested KP405, a brain-penetrant GLP-1/GIP agonist, engaged insulin signaling and neuroinflammation pathways in a small phase 1 study.
A phase 1 study of KP405, a novel brain-penetrant dual GLP-1/GIP receptor agonist, found exploratory changes in neuron-derived extracellular vesicle biomarkers of insulin signaling, neuroprotection, and neuroinflammation in healthy elderly participants and people with Parkinson disease (PD) after 7 days of treatment. Researchers presented the late-breaking data at the
“Pairing our drug with NeuraLight's precision biomarker platform puts KP405 in the strongest possible position to translate biological promise into clinical success,” said Ian Laquian, co-founder and CEO of Kariya Pharmaceuticals, which developed KP405 and is an author on the abstract.2
The study (KP405CS01) was a randomized, placebo-controlled, multiple-dose phase 1 trial giving 7 days of subcutaneous KP405 or placebo to separate cohorts of healthy elderly participants and patients with Parkinson's disease, with 8 participants per cohort (6 on KP405, 2 on placebo). Blood samples for brain-derived exosome analysis were collected on day -1, day 1, day 8, and day 14.
Across both cohorts, extracellular vesicle analysis showed that placebo-treated participants' insulin signaling, neuroprotection, and neuroinflammation scores generally stayed close to baseline over time, while KP405-treated participants showed statistically significant changes from baseline with greater variability. Increases in insulin signaling and neuroprotection scores and decreases in neuroinflammation scores were evident in some participants after 7 days of treatment and generally trended back toward baseline by the follow-up visit. Alpha-synuclein levels were reduced in the healthy elderly cohort on day 1.
The investigators characterized these as exploratory findings from a small safety and tolerability study; the trial was not designed or powered to assess clinical efficacy endpoints.
Mechanistically, KP405 incorporates a short cell-penetrating peptide sequence intended to help the molecule reach the brain directly, a feature meant to distinguish it from earlier GLP-1 drugs tested in PD. It is Kariya's lead program for PD; the company is also developing KP404, a related brain-penetrant dual GLP-1/GIP agonist in preclinical development for Alzheimer disease.2
GLP-1-class drugs have shown mixed results in PD trials to date. In the phase 2 LIXIPARK trial, lixisenatide slowed motor disability progression over 12 months compared with placebo, though gastrointestinal side effects, including nausea in 46% of treated patients, led experts to caution that the data were not yet sufficient to support prescribing the drug off-label.3
A larger phase 3 trial of exenatide, a different GLP-1 receptor agonist, found no significant benefit over placebo on motor scores over 96 weeks.4 That trial's findings are now under renewed scrutiny: in May 2026, The Lancet issued an Expression of Concern after a regulatory inspection identified department-wide good clinical practice concerns at one of the trial's six UK hospital sites, raising questions about the reliability of data from that site that have not yet been resolved.5
Neither lixisenatide nor exenatide is designed to cross the blood-brain barrier efficiently, a limitation KP405's cell-penetrating design is intended to address.2
Kariya is preparing a placebo-controlled phase 2a trial of KP405 in patients with Parkinson's disease, to be conducted with MAC Clinical Research in the UK. The company has partnered with NeuraLight to incorporate digital eye-movement measures and with NeuroDex for blood-based brain biomarkers into that trial, intended to provide more direct, quantitative evidence of whether the drug preserves brain function.2
