Combined results from two studies of an experimental Alzheimer's drug suggest it might modestly slow mental decline, especially in patients with mild disease.

Taken separately, the studies missed their main goals to significantly slow the mind-robbing disease. But pooled results found 34% less decline in mild Alzheimer's patients compared to those on a dummy treatment for 18 months.

Doctors say the results do not seem strong enough to win approval of the drug now. But they show researchers are on the right track by trying to clear the sticky deposits that clog patients' brains.

The drug is being developed by Eli Lilly & Co. (LLY 0.69%) and is called solanezumab. Results were reported Monday at a neurology conference in Boston.