2 New Alzheimer's Drugs Show Promise in Early Studies
Experts caution that expectations are low in field littered with drug failures
Indeed, most drugs in development face long odds of success. Only about 8 percent of drugs that reach human trials will eventually make it to market, according to the U.S. Food and Drug Administration.
"In the Alzheimer's field, it can be said to be zero, because we haven't a new drug in 10 years," said Rosenberg, who was not involved in the studies.
Hard as it is to hold out hope, Rosenberg said he probably would attend the presentation of the latest trials because, as he put it, "This is way new stuff."
The first study tested a drug called CHF5074 that's made by an Italian company called Chiesi Pharmaceuticals. The drug is believed to turn down inflammation in the brain by modulating microglial cells.
Microglia are the housekeepers of the brain. They keep its connections free of unwanted garbage, but they also produce chemicals that trigger inflammation, which can become toxic over time.
Ninety-six patients took one of three different doses of the drug or a placebo for the first 14 weeks of the study. Then researchers opened the trial, allowing study participants who wanted to continue to keep taking their original drug dosage. Seventy-four people chose to remain on the drug. All the patients had mild cognitive impairment, an early stage of memory loss that sometimes progresses to Alzheimer's disease.
Fourteen patients dropped out of the trial early. Three left because of adverse events. The main side effect reported in the study was diarrhea, which affected 16 percent of patients on the highest dose of the drug.
After 16 months on the drug, patients who remained on the drug saw significant improvements on some tests of memory and problem solving. The drug appeared to work especially well in patients who carried a gene called APOE4, which confers the highest genetic risk for Alzheimer's. APOE4 carriers saw improvements in test scores that were about one-third to one-fourth higher than before they started the study.
"Our study shows that we may, may, in some way help patients with their memory, perhaps because we're keeping the microglia from overactivity," said study leader Dr. Joel Ross, president of the Memory Enhancement Centers of America in Eatontown, N.J.