The results are now in: The Phase 2 clinical drug trial, sponsored by Transition Therapeutics, was a success! As many of you know, our Down Syndrome Program at Massachusetts General Hospital was one of three sites in the country selected to participate in this landmark study. We are thankful to the six adults with Down syndrome, and their caregivers, who participated at our clinic. Here's a summary of the study, and what this might mean for your son or daughter with Down syndrome in the future.

Q. What is the study drug supposed to do?
A. The study drug—called ELND005—is believed to have two potential benefits for people with Down syndrome: (1) prevent the accumulation of plaques that might contribute to Alzheimer’s disease, and (2) improve working memory and cognitive functioning by regulating myo-inositol levels in the brain.

Q. What type of trial did you do?
A. We just finished what’s known as a Phase 2 clinical trial. The main outcomes at this phase are to ensure that the study drug is both safe and effective. For any new drug to be available by prescription in U.S. drugstores, the FDA must first approve it. Before doing so, the FDA usually requires three phases of clinical trials to be completed with demonstrated success.

Q. What are the details of the study?
A. For this clinical trial, there were 23 adults with Down syndrome who participated in a 4-week treatment period. Of these, 6 adults received a “placebo”—that is, a fake pill that looks like the real medication. The other 17 received the study medication at varying doses. This trial was considered “double blind,” meaning that neither we at MGH nor our study participants knew which group they were in until the end of the study.

Q. Were there any serious side effects?
A. We are happy to report that there were no serious adverse events reported by any study participants. Side effects reported by seven participants on the study drug were all deemed mild in nature.

Q. Was it effective?
A. Throughout the course of the study, participants with Down syndrome and their caregivers completed what is known as the “Neuropsychiatric Inventory,” which assesses the severity of 12 symptoms, such irritability and agitation. Participants with Down syndrome who were on the study group were more likely to show improvement in their symptoms when compared to those receiving the placebo.

Q. What about cognition?
A. The number of participants enrolled was too small to draw any meaningful conclusions about the cognitive testing that was performed throughout the study. But, this was not the primary purpose of the study, so the testing will help inform the development of the next steps.

Q. What are the next steps?
A. The next step would have been to test ELND005 in a Phase 3 clinical drug trial. At this time, the company has decided not to pursue this next step.

For more information on all of the research opportunities at our Down Syndrome Program, please visit the Down Syndrome Research Program.

Dr. Brian Skotko