SAN DIEGO – Ladostigil, a drug that combines molecular characteristics of rivastigmine and rasagiline, was associated with some modest memory improvement and – perhaps more interestingly – a signal of brain volume preservation in a phase IIb study of patients with mild cognitive impairment.
Both whole brain and hippocampal volume after 3 years were about 1% higher in the trial’s active group than in the placebo group.
The volumetric data are potentially of more interest than the cognitive results, which didn’t meet the study’s primary endpoint of delaying or preventing conversion from mild cognitive impairment (MCI) to Alzheimer’s disease, Lon Schneider, MD, said at the Clinical Trials on Alzheimer’s Disease conference.
“The whole brain and hippocampal volume started to separate after 1 year and maximized at 2 years,” said Dr. Schneider of the University of Southern California, Los Angeles. “With hippocampal volume, we lose the significance of the effect by year 3, but when we continue on to the end there is a nominal significance in whole brain volume favoring the drug.”
He said the trial was plagued by a 35% dropout rate, probably because of perceived ineffectiveness of the drug. “Those numbers got in the way of looking at this outcome, particularly with 12 drops between years 2 and 3.”
Nevertheless, the drug will continue along its developmental pathway. The Israeli company developing it, Avraham Pharma, is seeking a larger pharmaceutical company with which to partner, according to its website.
Ladostigil pieces together molecular structures from both the monoamine oxidase-B inhibitor rasagiline and the anticholinesterase inhibitor rivastigmine (Exelon).
Avraham suggests that ladostigil could modify Alzheimer’s by neuroprotection, immune modulation, and reducing oxidative stress that leads the release of proinflammatory cytokines and microglial activation.
In 2012, the drug failed a phase II trial focusing on cognition in patients with Alzheimer’s. Afterward, Avraham lowered the dose from 80 mg to 20 mg and launched the current trial, with a refocus on MCI conversion.
It comprised 210 patients with MCI. The mean age was 71 years; mean Mini-Mental State Examination score was 28. About one-third were carriers of the high-risk apolipoprotein E4 allele. Patients were randomized to placebo or 20 mg ladostigil daily for 36 months. Brain MRI was performed at baseline and every 6 months throughout the trial.
The study failed to meet its primary endpoint of MCI conversion to Alzheimer’s. Fourteen patients in the active group and 20 in the placebo group progressed to Alzheimer’s. In year 3, there was a separation of curves with 4 vs. 10 patients progressing to Alzheimer’s, but overall the endpoint was not statistically significant (P = .16).
The two groups began to separate in the decline of brain volume around 1 year into the trial. For hippocampal volume, the difference was statistically significant only at 24 months. By 36 months, volume in the active and placebo groups overlapped slightly with a P value of .31.
The changes in whole-brain volume were somewhat more pronounced. The declining slopes in whole-brain volume began to separate at 12 months. At both 24 and 36 months, the differences were statistically significant (P = .033 and .036, respectively), with curves continuing to diverge at the study’s end.
Adverse events occurred in about 80% of patients (82% with active treatment vs. 79% with placebo); about 25% of both arms experienced serious adverse events.
Common adverse events were atrial fibrillation (8% vs. 3%), chest pain (5% vs. 3%), and benign prostatic hyperplasia (6% vs. 3%). Other events included dizziness, arthralgia, depression, and confusion.
None of the 35% who dropped out of the trial did so for an adverse event, Dr. Schneider noted.
The Neuropsychological Test Battery (NTB) and the Rey Auditory Verbal Learning Test (RAVLT) were secondary measures of behavior and cognition. Both showed positive trends for ladostigil, but neither was statistically significant.
Dr. Schneider has disclosed financial relationships with numerous pharmaceutical companies, but has no financial ties with Avraham.
On Twitter @alz_gal