The Rocky Mountain Alzheimer’s Disease Center (RMADC) at the University of Colorado Anschutz Medical Campus is reporting unexpected positive results related to thinking, memory, and everyday living for a drug being tested for Alzheimer’s disease.
The news comes from an interim report on the study of Leukine®, led by Drs. Huntington Potter, Jonathan Woodcock, and Tim Boyd, presented at the Alzheimer’s Association International Conference held in London in July.
“We say 'unexpected' because this phase of the clinical trial is primarily testing the drug for safety, so the improvement in cognition scores is a something of a bonus,” said Dr. Potter, Director of the RMADC and Director of the Alzheimer’s Disease Program for the Linda Crnic Institute for Down Syndrome.
The drug Leukine® is commonly used in bone marrow transplant patients to stimulate white blood cell production. The RMADC is the only organization currently evaluating the potential of Leukine® as an Alzheimer’s disease treatment.
The ongoing clinical trial is in early Phase 2, and the main outcome being tested is whether stimulating white blood cell production causes negative side effects. The participants in the double-blinded study all have been diagnosed with early stage Alzheimer’s disease, both men and women, ranging in age from 56 to 79 years. Half are receiving the study drug and half are receiving placebo. Participants received 15 injections over 18 days.
Drs. Potter and Boyd are also testing whether Leukine® removes the amyloid plaques and possibly helps the brain repair itself.
Alzheimer’s disease is the most common form of dementia, with more than five million Americans diagnosed currently. According to the Alzheimer’s Association, one in three seniors dies with Alzheimer’s or another dementia.
This interim report was presented at the Alzheimer’s Association International Conference in London using preliminary data. Because the original intent was to report on the safety of Leukine®, the scientists were not expecting to see noticeable study results on thinking, memory, or the ability to perform normal everyday activities.
“This is a short safety trial, lasting just under three weeks for each participant, and we weren’t expecting to see improvements in cognitive testing results,” said Dr. Boyd, who has been working with Dr. Potter on the Alzheimer’s treatment theory involving Leukine® since 2007. “For us to see these kinds of improvements gives us a lot of hope.”
The interim report states there were no indications of negative side effects that could be associated with the drug. In recent years, clinical trials on other potential drugs for Alzheimer’s have been plagued with reports of brain swelling and hemorrhaging.
“We were specifically looking for that,” said Dr. Boyd.
Dr. Potter said thinking and memory indicators were tested using the Mini-Mental State Examination (MMSE), a common evaluation tool in dementia diagnostics. At the end of treatment, the participants improved their baseline scores by a statistical measurement considered “significant.” When the same test was administered weeks after the treatment phases ended, the scores returned to levels closer to baseline.
The Activities of Daily Living (ADL) test also showed a positive uptick, suggesting improvement. ADL’s are critical to dementia evaluations because they reflect on whether an individual can live independently, or simply be left alone, or whether she or he requires a higher level of care.
The researchers will complete the safety phase of this current clinical trial this summer.
Dr. Potter said in the next part of the Phase 2 trial, participants will each receive injections five times a week for six months, with two-thirds getting the drug and one-third getting the placebo. This longer study, which will take around 18 months to complete, will include more time points to better evaluate whether Leukine® makes a measureable difference in thinking, memory, and amyloid plaques.
The positive safety results in this interim report, Dr. Potter said, justify moving forward with the longer study, which will be funded, in part, by a $1 million grant from the Alzheimer’s Association’s “Part the Cloud” initiative.
“We have a long way to go,” said Dr. Potter, “but these early preliminary results with Leukine® are encouraging enough to show that we should continue.”
Additional funding to investigate Leukine® as an Alzheimer’s disease therapy has been provided by the State of Colorado, the Dana Foundation, the Linda Crnic Institute for Down Syndrome, the Global Down Syndrome Foundation, and private philanthropy.