What is included under the term Investigational New Drug (IND)?

The term Investigational New Drug (IND) refers to a substance that is being used in clinical trials to assess its safety and efficacy before it can be marketed to the public. This definition directly includes biological products that are specifically used in support of clinical investigations. Such products may involve vaccines, gene therapies, or other biological agents that are not yet approved for general use but are being studied for their potential medical benefits.

In contrast, the other options do not meet the criteria for what constitutes an IND. A non-active placebo is used as a control in clinical trials but does not itself undergo the IND process since it is not an investigational product. Marketed drugs available for general use already have established safety and efficacy and therefore are not classified as INDs. Routine quality control products are not investigated in clinical trials for new effectiveness or safety parameters; they are assessed for compliance with regulations rather than being evaluated for therapeutic benefit. Thus, the definition and purpose of an IND align specifically with biological products utilized in clinical investigations, making that option correct.