A compound of Formula I is provided: or pharmaceutically acceptable enantiomers, salts or solvates thereof. The invention further relates to the use of the compounds of Formula I as TDO2 inhibitors. The invention also relates to the use of the compounds of Formula I for the treatment and/or prevention of cancer, neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and Huntington's disease, chronic viral infections such as HCV and HIV, depression, and obesity. The invention also relates to a process for manufacturing compounds of Formula I.