MOSCOW (AP) World Boxing Council president Mauricio Sulaiman says Alexander Povetkin has failed a doping test and sanctioning for the Russian heavyweight's title bout against Bermane Stiverne has been withdrawn.
Povetkin had been due to take on Stiverne for the WBC interim world title Saturday in Russia but the fight has now been called off.
In a post on Twitter, Sulaiman says Povetkin tested positive for the banned muscle-building substance ostarine.
It was Povetkin's second failed doping test this year.
He lost another title shot in May when he tested positive for meldonium shortly before a bout with Deontay Wilder.
On that occasion, the WBC accepted Povetkin's explanation that he had stopped taking the substance before it was banned for 2016.
