Katy Perry scores win as judge rules 'Dark Horse' didn't copy Christian rap track
The decision reverses a jury verdict from last year.
Pink trashes Dr. Luke: 'This is his karma'
The pop star said she won't work with the embattled producer, adding, 'he's not a good person'
Lady Gaga subpoenaed for Dr. Luke's lawsuit against Kesha
UPDATE: Lady Gaga's reps have responded