Recombinant Human Insulin in Global Diabetes Management - Focus on Clinical Efficacy.

Biosynthetic human insulin and insulin analogues are the mainstay of insulin therapy for both type 1 and type 2 diabetes although access to human insulin at affordable prices remains a global issue. The world is experiencing an exponential rise in the prevalence of diabetes presenting an urgent need to establish effective diabetes therapy in countries burdened by inadequate health care budgets, malnutrition and infectious diseases. Recombinant human insulin has replaced animal insulins and animal-based semisynthetic human insulin thereby available in sufficient quantities and at affordable prices able to provide global access to insulin therapy. In many patients, analog insulins can offer additional clinical benefit, although at a considerably higher price thus severely restricting availability in low income countries. The approval process for recombinant human insulins (i.e. biosimilars) and analogue insulins is highly variable in the developing countries in contrast to Europe and in North America, where it is well established within a strict regulatory framework. This review aims to discuss the future access to human insulin therapy in a global context with an ever increasing burden of diabetes and significant economic implications.

Recombinant Human Insulins - Clinical Efficacy and Safety in Diabetes Therapy.

Insulin replacement therapy is the standard of care for patients with type 1 and advanced type 2 diabetes mellitus. Porcine and bovine pancreatic tissue was the source of the hormone for many years, followed by semisynthetic human insulin obtained by modification of animal insulin. With the development of recombinant DNA technology, recombinant (biosynthetic) human insulin became available in large amounts by biosynthesis in microorganisms (Escherichia coli, yeast) providing reliable supplies of the hormone worldwide at affordable costs. The purity and pharmaceutical quality of recombinant human insulin was demonstrated to be superior to animal and semisynthetic insulin and patients with diabetes could be safely and effectively transferred from animal or semisynthetic human insulin to recombinant human insulin with no change expected in insulin dose. The decision for change remains a clinical objective, follow-up after any change of insulin product is recommended to confirm clinical efficacy. This review provides a summary and retrospective assessment of early clinical studies with recombinant insulins (Insuman®, Humulin®, Novolin®).

Equivalent Recombinant Human Insulin Preparations and their Place in Therapy.

Recombinant human insulin was one of the first products of biotechnology. It was developed in response to the need for a consistent and sufficient worldwide supply. Recombinant human insulin replaced the animal insulins and semisynthetic insulins obtained by modification of animal insulins. Bioequivalence studies were required for regulatory approval. Three reference products were independently established during these procedures: Humulin® (Eli Lilly and Co), Novolin® (NovoNordisk) and Insuman® (Sanofi). Numerous brand names have been used during the commercial development of recombinant human insulin formulations. In this review, three current brand names are used for consistent identification. Human insulin for Humulin and Insuman are produced by fermentation in bacteria (Escherichia coli) and for Novolin in yeast (Saccharomyces cerevisiae). The bioequivalence of recombinant human insulin products was investigated in euglycaemic clamp studies. An overview of such bioequivalence studies is provided here. This paper will consider the relevance of human insulin formulations today and their place in therapy.

Growth effects of insulin and insulin analogues.

The definition of mitogenic activity of insulin is controversial. Under physiological conditions, mitogenic refers to cell proliferation and tissue repair. In pathological conditions, it may refer to stimulation of tumour cells in pre-existing (undiagnosed) tumours. The in vitro investigations using benign and malignant cell lines compare proliferative activity of insulin molecules (animal, human and analogues). In these studies, inclusion of [B10-Asp] insulin would be a valuable link to the existing evidence on proliferation of mammary tissue in rodents. Animal and human insulin have growth promoting activity on spontaneously arising tumours (e.g. mammary tumours in rodents). They have no carcinogenic activity (cell transformation), and moreover insulin is not a co-carcinogen when evaluated in special toxicology. Mitogenicity (growth promoting activity) of insulin may be a problem in people with undiagnosed tumours, and may require definition of patient groups who would benefit from targeted monitoring.