Armstrong was recently stripped of all the titles he won from 1999 to 2005 after he was found guilty of doping.
The biopic will be based on Armstrong's fellow cyclist Tyler Hamilton's book, "The Secret Race", reported Sun online.
The book looks inside the world of professional cycling and explores the doping issue surrounding the sport and cancer survivor Armstrong, who has been stripped of his seven Tour de France titles.
"Most sports films end in an inspirational victory. It is hard to work out what the ending would be. Lance was a hero before this scandal. The current ending is too depressing. It would be a more appealing story with a more hopeful final act," a source said.
