The mesylate salt form of the antiviral agent nelfinavir. Nelfinavir selectively inhibits human immunodeficiency virus (HIV) protease, thereby preventing cleavage of the gag-pol viral polyprotein and resulting in the release of immature, noninfectious virions. In vivo, this agent exhibits broad tissue distribution compared to related agents. or Treatment given as a first step to shrink a tumor before the main treatment, which is usually surgery, is given. Examples of neoadjuvant therapy include chemotherapy, radiation therapy, and hormone therapy. It is a type of induction therapy.