A closely watched Phase II study of an experimental Alzheimier’s drug being developed by Elan and Wyeth shows the med appears to be effective in some patients. Known as bapineuzumab, the drug failed to achieve statistically significant results in the primary outcomes, but managed to do so in subgroups lacking a higher genetic risk to develop the disease.

Given the lack of progress in treating Alzheimer’s, the drug is being hailed as the next potential advance in treating the disease and Wall Street analyst Ian Sanderson of Cowen & Co. is forecasting already forecasting annual sales of $7 billion by 2015. However, more detailed findings are due to be carefully scrutinized at the International Conference on Alzheimer’s Disease in Chicago in July.

The drug is generating a great deal of enthusiasm as patients, doctors and investors look for signs it can slow mental deterioration and improve cognitive functions, as opposed to existing treatments that slow symptoms. Bapineuzumab is based on a new approach aimed at reducing so-called amyloid plaque in the brain that is believed to cause Alzheimer’s.

The Phase II trial had not been expected to show overall statistical significance, since there were only 240 patients, but the drugmakers say the results were clinically meaningful in a genetic subgroup of patients known as ApoE4 non-carriers, who make up between 40 and 70 percent of the Alzheimer’s disease population.

“The preliminary analyses of the Phase 2 study are a continued validation of the amyloid approach to Alzheimer’s disease and an important milestone in our companies’ ongoing commitment to bring new treatment options to patients,” Kelly Martin, Elan’s ceo, in a statement. “These results clinically support our decision to move into Phase 3 last year.”