This annex provides a list of comparator products for equivalence assessment of interchangeable multisource (generic) products. The information on comparator pharmaceutical products was collected by the Secretariat from drug regulatory authorities and pharmaceutical companies. The list has been drawn up to assist regulatory authorities and pharmaceutical companies in deciding on appropriate comparator products in the context of multisource (generic) marketing authorization. The information could also be used for drug procurement purposes. Where the comparator pharmaceutical product is not clearly defined, criteria are suggested that are provided in a decision-tree format (see Figure 1). This permits the selection of a comparator pharmaceutical product.
The guidelines on registration requirements to establish interchangeability of multisource (generic) pharmaceutical products published by WHO (1) state that multisource products must satisfy the same standards of quality, safety and efficacy as those applicable to the corresponding innovator product. They recommend that quality attributes of a multisource product should be tested against the innovator product for which interchange is intended.
The innovator product is usually the most logical comparator product because its quality, safety and efficacy should have been well assessed in pre- and post-marketing studies and, in addition, the data on its safety and efficacy are usually linked to a pharmaceutical product with defined specifications for quality and performance. Despite acceptance of the general objective, there is no agreement on the criteria for selecting a list of international comparator products, nor does a list of such products exist. The comparator product chosen is either the most widely used “leading” product on the market or the product that was first introduced in that market. For this reason, among others, significant differences may exist between the comparator products used in different countries.