The Voluntary Anti-Doping Association said it had informed the Association of Boxing Commissions and the British Boxing Board of Control that a “random anti-doping protocol” undertaken by Whyte had returned the adverse findings, leading to the bout being called off and an investigation being launched.
The fight had been due to take place at London’s O2 Arena on Saturday, August 12.
Fight promoter Matchroom said in a statement: “Today, the Voluntary Anti-Doping Association (VADA) informed Matchroom, the Association of Boxing Commissions and the British Boxing Board of Control that Dillian Whyte had returned adverse analytical findings as part of a random anti-doping protocol.
“In light of this news, the fight will be cancelled and a full investigation will be conducted.”
Whyte has insisted he is innocent after the verdict was revealed.
He said in a statement: “I am shocked and devastated to learn of a report by VADA of adverse findings relating to me.
“I only learned of it this morning and am still reacting to it. I have also just seen the fight is being cancelled without having any chance to demonstrate my innocence before the decision was taken.
“I can confirm without a shadow of a doubt that I have not take the reported substance, in this camp or at any point in my life.
“I am completely innocent and ask to be given the time to go through the process of proving this without anybody jumping to conclusions or a trial by media.”
Previously, the pair had fought in the amateur ranks before Joshua won gold at the 2012 London Olympic games.
As professionals, they competed for the heavyweight title in 2015 which Joshua won with a seventh-round knockout. A rematch was announced in early July after talks over Joshua taking on Tyson Fury broke down while the former world champion had also been linked with a fight against Deontay Wilder in Saudi Arabia.
White had a doping violation dropped in 2019 after it was found that the levels of a banned steroid were “very low” and he was not at fault.
