Immunocontraceptives.

ABSTRACT

The advent of immunocontraceptives represents the first truly novel approach to the development of family planning methods in over 30 years. Such products would have many advantages over existing contraceptives in that they would not elicit metabolic disturbances, would provide long-acting (i.e. 6 to 12 months) protection from pregnancy, be easy to administer, be economical to manufacture and distribute, and could, depending on their composition, be used by either men or women. Several lines of research and development currently in progress are aimed at the development of safe and effective immunocontraceptives based on reproductive hormones, components of the gametes (sperm and ova) and products of the early pre-implantation conceptus. The only prototype immunocontraceptives to have reached the stage of clinical trials in women are those based on the hormone human chorionic gonadotropin, and in men that based on follicle-stimulating hormone. However, extensive research is also underway on immunocontraceptives based on sperm and ovum components for use by women, and on immunocontraceptives based on sperm components and gonadotropin-releasing hormone for use by men. Before such preparations can be made available for wide-scale use, further research is needed on ways to overcome genetically determined variations in individual immune responses so that protective responses of a predetermined duration can be elicited in all recipients. It is anticipated that these technical problems can be solved and the clinical testing of lead products will be completed in the next decade. Almost all of the financial support for the research and development of immunocontraceptives has been provided by academic institutions and public sector agencies. In general, the pharmaceutical industry has not been willing to engage in new contraceptive development, largely because of concerns about product liability claims, anticipated low profitability and/or the risk of negative publicity. Therefore, the further development, manufacture and distribution of immunocontraceptives will probably require the collaboration of public sector agencies, governments and industry in order to overcome the current paucity of effort being put into the development and provision of new, safe, effective and acceptable methods of family planning. The purpose of this review is to provide information on the current status of research and development of potential immunocontraceptives and to attempt to stimulate pharmaceutical companies to reassess their positions with regard to the development, manufacture and distribution of these products.