Dr J. Idanpaan-Heikkila, World Health Organization

Many obstacles have been identified in the development of CTD. Although the ICH guidelines cover many subtopics there are, as yet, no complete ICH guidelines covering the totality of requirements for quality, safety and efficacy. This means that gaps must be filled by national regulations.

Moreover, ICH CTD covers only new drug substances and products, excluding the widely used, well established substances and the multisource (generic) products that make up a substantive part of the daily work of drug regulators worldwide. GMP and quality requirements for starting materials, excipients, and active pharmaceutical ingredients have proven to be difficult and complicated areas of harmonization within the CTD.

ICH stability guidelines do not cover generic products or climatic zones III and IV (hot and dry and hot and moist) that are both critical and typical for many developing and tropical countries. Although agreement may exist for safety documentation, efficacy requirements which cover a variety of diseases are difficult to harmonize.

The potential benefits of CTD can be extensive. A single format CTD could facilitate communication and exchange of information between regulators and the industry. Application made by electronic submission would be easier and industry could save in resources and time if the content of one application was the same for all ICH regulators. Finally, CTD could facilitate the evaluation process carried out by regulators but harmonization of current regulatory assessment procedures in ICH countries is also required.

As the potential benefits of CTD relate currently to tripartite countries alone, they should ideally be extended to regulators and industries worldwide. However, in order to succeed in this worldwide approach, CTD should be applicable to all countries. This requires all partners concerned to be involved in the negotiation process as early and as fully as possible. WHO is the only existing worldwide forum which could succeed in this task.