Weaver filly tests positive for banned substance at Aqueduct

A filly trained by George Weaver tested positive for metformin, a banned substance, after racing at Aqueduct on March 16.

Anna's Wish, a 3-year-old daughter of Dialed In, tested positive for metformin after finishing third of four in the black-type Cicada Stakes.

She has been suspended while the case is pending, according to a Horseracing Integrity & Welfare Unit posting Thursday. Weaver did not reply to a request for comment.

Metformin is prescribed to treat type 2 diabetes in humans. It has been used in horses to counteract the effects of equine metabolic syndrome, according to Kentucky Equine Research. But studies have shown that intestinal absorption of metformin in horses is poor and that metformin may not improve insulin sensitivity in ponies, according to the organization.

Horseracing Integrity and Safety Authority rules state that banned substances should never be in a horse's system or used on a horse because they serve no legitimate treatment purpose.

In February, trainer Jonathan Wong was suspended for two years for a metformin violation, a ruling that he planned to appeal.