Answer
Lucas Browne, a former WBA world heavyweight champion, failed a drug test in 2016, leading to the reinstatement of Ruslan Chagaev as the champion. Browne's positive test result for a banned substance, ostarine, came after his victory over Chagaev in March of that year. The result meant that the fight was overturned, and Chagaev was declared the winner by technical knockout.