- Please note that an experimental agent in this setting is defined as any drug or device used under an IND designation which is associated with systemic effects that could influence the outcome in a patient with severe VOD. If the continued use of an experimental agent is considered both necessary and appropriate, this must be reviewed and approved on a case by case basis by the Overall Study PI, Dr. Paul Richardson, or his designate, who will approve the entry of patients being concurrently treated with another experimental agent only if there is no evidence for a potential adverse pharmacokinetic interaction or overlapping toxicity.