This is an expanded access program (EAP) for eligible participants. This program is designed to provide access to ABBV-8E12 prior to approval by the local regulatory agency. Availability will depend on territory eligibility. Participating sites will be added as they apply for and are approved for the EAP. A medical doctor must decide whether the potential benefit outweighs the risk of receiving an investigational therapy based on the individual patient's medical history and program eligibility criteria.