August 2012 has been a busy month for late-stage testing of long awaited Alzheimer’s drugs. Unfortunately, the results haven’t been good. In early August, information was released disclosing that Pfizer’s bapineuzumab did not meet the primary endpoints set up by the studies, and trials were stopped. Now, Eli Lilly has also announced that their contribution to the Alzheimer’s battle, solanezumab, did not meet the primary endpoints, both cognitive and functional, in either of the two Phase 3, double-blind, placebo-controlled studies on the drug.
Lily is holding back on calling the drug trial a failure. According to the company, “a pre-specified secondary analysis of pooled data across both trials showed statistically significant slowing of cognitive decline in the overall study population of patients with mild-to-moderate Alzheimer’s disease.”
Some scientists consider this somewhat optimistic in that tests with people who had moderate AD did not show enough statistical improvement to be useful, and even early AD patients did not show significant enough improvement to be important.
According to In the Pipeline, “they modified the endpoints (that is, lowered the bar and narrowed down to a select population) in the data for the second Phase III before it finished up. And even then, the antibody missed. So what we have are trends, possible trends, but nothing that really gets to the level of statistical significance.”
Bapineuzumab and solanezumab were similar drugs focusing on stopping or reversing the development of Amyloid plaques, which are insoluble fibrous protein aggregates in the brain commonly associated with Alzheimer’s disease.
Gammagard (IVIG) therapy showed somewhat better results
In the first of the three late-stage drug trials, Gammagard showed the most promise. Gammagard is an intravenous immunoglobulin, or IVIG therapy. Gammagard was shown in a small study to halt the cognitive decline in some individuals with Alzheimer’s disease. The drug contains antibodies from people who don't have Alzheimer's. It appears that intravenous immunoglobulin therapy may successfully attack Amyloid, the plaque in the brain, as the other drugs were meant to do. This study only had 16 participants, and the treatment would be so expensive if it is proven to be effective in larger studies, that it is not likely to be expanded into general use anytime soon.
Tests that fail still produce information
Advocates for curing Alzheimer’s disease were, in general, hoping to see some very real progress come out of these drug trials. As it stands, they have at least gotten some negative information. Even with the drug failures, new knowledge is gained. Researchers now know that they must look in other directions or at other modifications of existing drugs, as they strive to find a ways to prevent or to cure the disease.