Enrollment is undetermined as multiple duvelisib studies are allowed to rollover active subjects with Verastem's approval. Subjects in active treatment and subjects in survival follow-up are allowed to rollover to this study. For subjects on active treatment, subjects will continue the same dose from their previous duvelisib study and will take duvelisib twice daily (BID) for 28 day continuous cycles until disease progression or unacceptable toxicity. For subjects in survival follow-up, subjects will continue to be followed for survival in this study for the duration outlined in their previous duvelisib study.