12. Patients who are receiving drugs that are sensitive substrates of CYP450 1A2, 3A4, 2C9, 2C19 or 2D6, or strong inhibitors or inducers of all major CYP450 isozymes that cannot be stopped at least 7 days or 5 half-lives (whichever is longer) before starting treatment with ABC294640 and either replaced with another appropriate medication or not given for the duration of the clinical study.