Dawson, who now appears in Marvel's Netflix series and previously starred in comic book adaptations Sin City and Josie and the Pussycats, was in talks to take on the role, but a deal never came together.
Aside from the new cast, James McAvoy will be returning in the "New Mutants" film to reprise his role as the young Professor X, also known as Charles Xavier.
The Hollywood Reporter has published an item stating that Daredevil star Rosario Dawson has left the X-Men spinoff film, New Mutants, and will be replaced by Brazilian superstar Alice Braga. Reasons for her departure are "unclear". Boone and his writing partner, Knate Lee, wrote the script for the project, which is set to shoot in July in Boston.
Production is moving quickly on 20th Century Fox's upcoming X-Men spin-off, New Mutants, and that means one actress is, unfortunately, going to miss out.
Cecilia Reyes is described as a doctor who has the power to generate a protective bio-field around herself.
Brazil-born Braga has appeared in movies such as I Am Legend with Will Smith, Predators and Elysium.
Josh Boone's New Mutants arrives in cinemas on April 13th 2018, with Dark Phoenix, directed by franchise stalwart Simon Kinberg, scheduled for later the same year on November 2nd.