HBO announced that it is canceling the race-track drama "Luck" after a third horse died during production Tuesday.

"Luck", which stars Dustin Hoffman, has been the target of attacks by animal-rights activsts, including PETA, after one horse had to be destroyed after breaking its leg during the filming of the show's pilot. A second horse was euthanized later.

 In a statement, HBO said, "Safety is always of paramount concern. We maintained the highest safety standards throughout production, higher in fact than any protocols existing in horseracing anywhere with many fewer incidents than occur in racing or than befall horses normally in barns at night or pastures. While we maintained the highest safety standards possible, accidents unfortunately happen and it is impossible to guarantee they won’t in the future. Accordingly, we have reached this difficult decision."