Experimental Drug CN-105 Shows Promise in Reducing Postoperative Delirium in Older Adults
Key Insights
CN-105, an experimental apolipoprotein E (search) mimetic peptide developed at Duke University, demonstrated safety and tolerability in a phase 2 clinical trial involving 186 older surgical patients.
The drug showed a promising trend toward reducing postoperative delirium (search), with 19.3% of CN-105 patients experiencing delirium compared to 26.5% in the placebo group, representing an approximate 25% relative risk reduction.
Patients receiving CN-105 had fewer overall complications, with a median of one moderate or serious complication versus two in the placebo group.
An experimental drug designed to combat brain inflammation has shown promising early results in reducing postoperative delirium (search) among older adults, according to findings from the phase 2 MARBLE clinical trial published in JAMA Network Open. The drug, CN-105, represents a potential breakthrough in addressing one of surgery's most common and costly complications.
Safety Profile Establishes Foundation for Further Development
The primary objective of the MARBLE trial was to establish CN-105's safety profile, and the drug performed well on this critical measure. In the triple-blind randomized clinical trial conducted between April 2019 and December 2022, 186 patients aged 60 years or older undergoing noncardiac, nonintracranial surgeries were enrolled and randomized in a 3:1 ratio to receive either intravenous CN-105 or placebo.
"CN-105 was found to be well-tolerated among older surgical patients," the researchers reported. The proportion of patients experiencing moderate to severe adverse events was slightly lower in the CN-105 group compared to placebo, though the difference was not statistically significant. Notably, patients receiving CN-105 had fewer adverse events per individual, indicating a potential clinical benefit.
The drug demonstrated excellent feasibility in the perioperative setting, with more than 90% of doses in both groups administered within the predefined time window. CN-105 was given within one hour before surgery and then every six hours until discharge or up to 13 doses.
Encouraging Trends in Delirium Prevention
While the study was not powered to measure effectiveness definitively, researchers observed encouraging trends in delirium prevention. Postoperative delirium (search) affected 19.3% of patients who received CN-105, compared with 26.5% of those in the placebo group. This approximate 25% relative risk reduction favored the drug, though it did not reach statistical significance, likely due to the modest sample size.
"Even a modest reduction could translate into shorter hospital stays, lower costs, and a better quality of life," said lead author Miles Berger, MD, PhD, an anesthesiologist and perioperative care researcher at Stanford Medicine.
Beyond delirium prevention, patients who received CN-105 before surgery had fewer complications overall, with a median of one moderate or serious complication, such as infection, digestive or blood-related issues, compared to two in those who did not receive the treatment.
Targeting Neuroinflammation at Its Source
CN-105 is a lab-made peptide developed at Duke University School of Medicine to mimic the protective effects of apolipoprotein E (search) (APOE), a protein linked to brain health. The drug's design addresses scientists' growing belief that inflammation is a key driver of postoperative delirium (search).
"The idea is that postoperative delirium (search) may be an acute, short-term version of the type of inflammatory processes that drive longer-term neurodegenerative diseases," Berger explained. Surgery triggers inflammation across the body, and in more vulnerable brains, that surge can briefly scramble thinking and awareness.
One significant risk factor is the APOE ε4 gene variant, which is tied to Alzheimer's disease (search) and heightened inflammation in the brain. To target these inflammatory processes, Duke scientists reverse engineered APOE's neuroprotective effects into a drug refined enough to cross the blood-brain barrier and reduce harmful inflammation.
Addressing a Critical Healthcare Challenge
Postoperative delirium (search) represents a substantial healthcare burden, affecting roughly one in four older patients who develop confusion and altered awareness in the hours and days after surgery. The condition costs the U.S. healthcare system an estimated $80 billion annually.
"Delirium remains one of the most common, costly and under addressed complications of surgery in older adults," Berger noted. "There is a critical need for new approaches that target its underlying biology."
Currently, no medications are specifically approved to treat or prevent postoperative delirium (search), making CN-105's development particularly significant as it could become the first medication to address this condition.
Path Forward to Phase 3 Trials
The researchers acknowledged several limitations in their study, including the single-center design, relatively small sample size, and variability in surgical procedures. The trial was also not powered to determine the most effective dosing strategy, and no significant differences were observed in postoperative inflammatory biomarkers between the groups.
Despite these limitations, first study author Noah Timko, MPH, a clinical research coordinator in the Duke Department of Anesthesiology, emphasized that the results set the stage for a larger clinical study to determine whether the drug truly reduces postoperative delirium (search).
The drug's ability to cross the blood-brain barrier and its favorable pharmacokinetic profile make it a promising candidate for further investigation. The findings pave the way for larger, well-powered phase 3 trials to determine whether CN-105 can meaningfully reduce postoperative delirium (search) and improve outcomes in the growing population of older surgical patients.