Colombian Oscar Tovar has been stripped of his Gran Fondo New York 2015 title after it was discovered he was competing on synthetic testosterone.
Tovar tested positive during an in-competition doping test administered by the US Anti Doping Agency after crossing the line first in May.
Under World Anti Doping Agency rules, Tovar will be banned from any competition for two years and has been handed a lifetime ban from any GFNY event.
“We are of course upset and hurt that a doper taints the reputation of our race and had us celebrate him on the day,” said GFNY CEO Uli Fluhme.
“However, it’s without a doubt more important for us to do what we can to make our race fair, of which doping controls are an integral part.
"Simply looking away and not testing the athletes is the worst decision that a race director can make because it forces everyone to take drugs to try to level the playing field.”
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The GFNY series established doping controls in 2012, catching two participants using EPO that year. The samples from 2013 and 2014 were all negative, the event reported.
As well as doping, event organisers also check a selection of bikes for any concealed motors.
In the Cycling Independent Reform Commission (CIRC) report earlier this year, several riders reportedly said they no longer wish to ride Gran Fondo races around the world because they couldn't compete with doping competitors.