This research study is for men and women who have been diagnosed with hematological or solid tumor indications or advanced malignancies and who participated previously in studies (a parent study) involving pelabresib, an experimental anti-cancer drug.

If their study doctor thinks they derived clinical benefit from treatment with pelabresib in the parent study, the purpose of this study is to provide the participant with continued access to pelabresib and to continue collecting safety and effectiveness information.
   
If a participant discontinued pelabresib study treatment in the parent study for any reason other than participating in this extension study, or they received placebo in the parent study, they will NOT receive pelabresib treatment on this study. However, they can take part in this study to be followed up for the collection of survival data, which includes overall survival and leukemic-free survival data.

Pelabresib is a study drug because it has not been approved by the U.S. Food & Drug Administration (FDA).
   
For participants receiving continuous pelabresib study treatment, they will take pelabresib in the same way they did in the parent study. The study drug will be provided as tablets taken orally. The duration of their study participation will depend on how long they may benefit from the study drug and when they will have access to pelabresib outside of the clinical study. This can be for up to approximately 5 years. 
   
For participants joining the survival follow-up only (NOT receiving pelabresib), the duration of their study participation will be as long as they are willing to be followed up until the study ends. This can be for up to approximately 5 years.