Andreu, who as part of the U.S. Postal Service team helped American compatriot Armstrong win the Tour in 1999 and 2000, said in an interview with the New York Times that he had used erythropoietin (EPO) before the first of those races.
Speaking to Spanish sports daily Marca on Wednesday, Johan Bruyneel said "I do not understand why he [Andreu] goes on making these unfounded statements."
Belgian Bruyneel, who directed Armstrong from 1999 until the American's retirement in 2005, said Andreu was a "pitiful man."
"An American judge has already shown that Andreu has no credibility."
"In any case, neither me nor Lance are losing any sleep over this, because his attacks are no longer a surprise."
Bruyneel, the Discovery Channel sporting director, is currently leading his team at the Tour of Spain.