Human gene therapy seeks to modify or manipulate the expression of a gene or to alter the biological properties of living cells for therapeutic use. We, FDA, are providing you, sponsors of human gene therapy Investigational New Drug Applications (INDs), recommendations regarding chemistry, manufacturing, and control (CMC) information submitted in an IND. The purpose of this guidance is to inform sponsors how to provide sufficient CMC information required to assure product safety, identity, quality, purity, and strength (including potency) of the investigational product (21 Code of Federal Regulations (CFR) 312.23(a)(7)(i)). This guidance applies to human gene therapy products and to combination products that contain a human gene therapy in combination with a drug or device.