NEW YORK » Drug developers Pfizer and Medivation are ending the development of a potential Alzheimer’s disease treatment after the drug yielded disappointing results in a late-stage clinical study.

The companies say dimebon failed to achieve statistically significant improvements in cognitive ability and measurements of self care and daily function in patients with mild-to-moderate cases of the disease. The study involved about 1,000 patients who had dimebon added to their ongoing treatment with Alzheimer’s drug donepezil.

The companies are ending development of dimebon, as well as their agreement to co-develop and market the potential treatment.

Pfizer Inc. and Medivation Inc. said last April that dimebon failed in another late-stage clinical trial, when it did not improve symptoms of the neurologic disorder Huntington’s Disease.

Pfizer, based in New York, is the world’s largest drugmaker.