Protein therapeutics have several advantages over small molecule drugs. First, proteins usually have highly specific and complex functions that cannot be mimicked by simple chemical compounds. Second, there is often less potential for protein therapeutics to interfere with normal biological processes and cause adverse reactions, as the action of proteins is highly specific. Third, since the body naturally produces many proteins as therapeutics, these agents are generally well tolerated and are unlikely to elicit immune responses. Fourth, for diseases caused by gene mutations or deletions, protein therapeutics can provide effective alternative treatments without the need for gene therapy.