A Reproductive and Developmental Toxicity Study in CD Rats of LY275585, [Lys(B28),Pro(B29)]-Human Insulin

Insulin analogs and pregnancy: an update

It is well known that good metabolic control maintained throughout pregnancy reduces maternal and fetal complications in diabetes. Before conception and throughout pregnancy, insulin therapy needs to be optimized and, in this context, the insulin analogs currently available in the market may help to achieve good metabolic control. We therefore review here what is known about the potential benefits and risks related to the use of these new insulins in pregnancy. Clinical and experimental data on insulin aspart and lispro strongly suggest that they have no adverse maternal or fetal effects during pregnancy in women with pregestational and gestational diabetes, and that their use results in improved glycemic control, fewer hypoglycemic episodes, and improved patient satisfaction. At present there are no published data on the use of glulisine in pregnancy. Insulin glargine during pregnancy is not recommended but, in the last years, larger surveys (retrospective and case-control studies) have been published on this field and, to date, results of about 335 pregnancies with type 1 diabetes are available showing an incidence of congenital malformation similar to that obtained with human insulin. There are no published data concerning the use of detemir in pregnancy but the results of a prospective study are expected in 2010.

The potential for the use of insulin lispro in pregnancy complicated by diabetes

The target of improved perinatal outcome in diabetic pregnancies may be achieved by new insulin preparations that more closely mirror the physiological response of insulin and not exclusively the traditional means of strict adherence to diet and frequent blood glucose testing.No insulin preparation has been systematically tested in pregnancy; it is a responsibility of all clinicians who look after pregnant diabetic women to record the outcomes of IL-treated pregnancies. More data is needed before this preparation can be either recommended in pregnancy or alternatively avoided.

Early and late onset side effects of short-acting insulin analogue in seven Japanese diabetic patients

Short-acting insulin analogue has previously shown to be equal to short-acting human regular insulin regarding in vitro characteristics, immunogenicity, and safety. But in the present study, we experienced seven patients who had mild to moderate side effects due to short-acting insulin analogue. These side effects could be divided into two types based on the appearance time; one with early onset and the other with late onset. Early onset side effects include rash, disturbances in walking and general fatigue that can not be explained by the swing in glucose levels. These symptoms appeared 2-3 days after the use of short-acting insulin analogue and disappeared several hours after switching short-acting human regular insulin. The late onset side effect is bilateral leg edema, which appeared 1-2 months after the induction of short-acting insulin analogue and disappeared after several hours by changing to short-acting human regular insulin. We should monitor the early and late onset side effects as diligently as possible when we use short-acting insulin analogue on diabetic patients.

Novel insulin analogues and its mitogenic potential

Insulin analogues were developed to modify the structure of the human insulin molecule in order to more accurately approximate the endogenous secretion of insulin. With the help of recombinant technology and site-directed mutagenesis, the insulin molecule can be modified to either delay or shorten absorption time, providing better insulin treatment options and facilitating the achievement of glycaemic goals. Changing the structure of the insulin molecule, however, may significantly alter both its metabolic and mitogenic activity. Multiple factors such as residence time on the receptor, dissociation rate, rate of receptor internalization and the degree of phosphorylation of signalling proteins can affect the mitogenic potencies of insulin analogues. Changes in the structure of the insulin have raised concern about the safety of the insulin analogues. For example, questions have emerged about the relationship between the use of insulin lispro and insulin glargine and the progression of diabetic retinopathy. Two studies have shown progression of retinopathy with the use of insulin lispro. However, others have not confirmed these results, and causality could not be proven as progression of retinopathy can occur with rapid improvement in glycaemic control, and methods of assessments among studies were not consistent. Therefore, we examine the metabolic and mitogenic characteristics of the three insulin analogues, insulin lispro, insulin aspart and insulin glargine, that are currently on the market, as well as the two insulin analogues, insulin glulisine and insulin detemir, that are soon going to be available for clinical use.

New advances in insulin treatment of diabetes: overcoming barriers

OBJECTIVE

To discuss the optimal role of insulin in the treatment of patients with diabetes mellitus.

METHODS

We review the complications of diabetes, highlight the attempts to improve control of plasma glucose, and summarize current recommendations for use of insulin in clinical practice.

RESULTS

With the strict new guidelines for the diagnosis of diabetes issued by the American Diabetes Association in July 1997--a plasma glucose level of 126 mg/dL (7 mmol/L) rather than 140 mg/dL (7.8 mmol/L)--an additional 8 million persons will be diagnosed this year, and diabetes and its complications will be at the forefront of public health concerns. Strong evidence indicates that with reduction of plasma glucose levels and tight control of glycohemoglobin, the rate of complications can be considerably decreased. Although insulin replacement therapy is well known to be both the best and the most cost-effective way to control glucose levels in patients with type 1 diabetes, studies have no shown that those with type 2 diabetes can likewise benefit from appropriate insulin therapy. Other investigations have indicated that coronary events are as likely to occur in patients with recently discovered impaired glucose tolerance as in patients with known diabetes (at a 2-hour postprandial glucose threshold of 96 mg/dL [5.3 mmol/L]). Such finding suggest that there may be no such thing as "borderline diabetes" and give impetus to the search for improved types of insulin to treat all patients with diabetes. A recent candidate is the new insulin analogue lispro, which was developed by recombinant DNA techniques, with its design influenced by the structural analogy to another endogenous hormone, insulin-like growth factor I. Lispro is a fast-acting, rapidly dissipating insulin formulation. This profile allows lispro to be given less than 15 minutes before a meal, yet with little risk of postprandial hypoglycemia because its high mealtime peak is followed by rapid disappearance from the bloodstream.

CONCLUSION

Lispro has been shown to improve postprandial control of plasma glucose and to decrease the occurrence of hypoglycemia episodes in comparison with regular insulin. Because of its stability and pharmacokinetic properties, lispro can also be used in insulin pump therapy.

Transfer of insulin lispro across the human placenta: in vitro perfusion studies

OBJECTIVE

Insulin lispro (Humalog), a human insulin analog, has a more rapid onset, earlier peak, and shorter duration of glucose lowering activity than regular human insulin. However, it is not known whether insulin lispro crosses the human placenta and reaches the fetus. Therefore, the objective of the present study was to examine whether insulin lispro crosses the placenta using the technique of perfusing a human placental lobule in vitro.

RESEARCH DESIGN AND METHODS

Term human placentae from uncomplicated pregnancies were obtained immediately after delivery. Insulin lispro, at concentrations ranging from 100 to 1000 micro U/ml, was introduced into the maternal reservoir. The maternal side of the placenta was perfused with constant concentration of lispro insulin; the fetal circulation was closed. Samples were drawn from both the maternal and fetal circulations at regular intervals. The appearance of insulin lispro in the fetal circulation was analyzed by a specific radioimmunoassay.

RESULTS

No placental transfer of lispro could be detected during perfusion with 100 and 200 micro U/ml. In contrast, there was a small concentration-dependent transfer to the fetus at concentrations of 580 micro U/ml and higher, detectable after at least an hour of constant concentration of insulin lispro during perfusion. The rate of placental transfer was 0.019 micro U x min(-1) x g tissue(-1) at maternal levels of 580 micro U/ml and 0.045 micro U x min(-1) x g(-1) tissue at maternal levels of 1000 micro U/ml. Measuring lispro levels in 11 pregnant women revealed that a dose of 50 units may achieve serum concentrations >200 micro U/ml with apparent linear correlation between dose and levels.

CONCLUSIONS

Insulin lispro is not likely to cross the placenta at a single standard dose. This study suggests that insulin lispro is unlikely to reach or harm the unborn baby.

The utility and efficacy of the new insulins in the management of diabetes and pregnancy

The quest for tight glucose control has led to the development of insulin analogues (insulin lispro, insulin aspart, insulin glargine) designed to optimize glucose control while minimizing the impact of insulin therapy on daily life. Women with diabetes are increasingly likely to become pregnant on these new products and to benefit from their use while pregnant. Caution over the use of new medications in pregnancy has limited experience, but increasing evidence is emerging that use of insulin lispro is not associated with excess risk of fetal malformations, is associated with similar or better outcomes during pregnancy, and is preferred over regular insulin. Similar evidence for the other insulin analogues has yet to emerge, but is unlikely to be dissimilar.

Insulins today and beyond

The advent of insulin almost 80 years ago revolutionised treatment of diabetes and must be one of the most outstanding achievements of twentieth century medicine. Since then, there has been an ever-increasing awareness and acceptance of the need to achieve and sustain near-normoglycaemia to delay onset and retard progression of diabetic angiopathy. Physiological insulin replacement is therefore central to management of patients with diabetes who are unable to make [corrected] insulin. Insulin formulations, treatment strategies, and methods and routes of delivery have changed much, with more and more options for monitoring the effect on blood glucose concentrations. Patients with type 1 and type 2 diabetes need insulin much more aggressively than previously. Parallel developments in glucose-sensing technologies are welcomed as an integral part of safe and optimum implementation of insulin replacement therapy.

Insulin lispro: its role in the treatment of diabetes mellitus

OBJECTIVE

To introduce a rapid-acting human insulin analog, insulin lispro; to review its pharmacology, therapeutics, pharmacokinetics, dosing guidelines, adverse effects, and drug interactions; and to summarize the clinical trials of its efficacy and safety alone and in comparison with regular human insulin in the treatment of diabetes mellitus.

DATA SOURCES

A MEDLINE database search was completed to identify all relevant articles, including reviews; Eli Lilly and Co.; published articles and abstracts; and review chapters from medical textbooks.

STUDY SELECTION

Due to the relatively few citations listed in MEDLINE (12 as of December 1995), most of the studies reported were found from abstracts summarizing the clinical action, adverse effects, or pharmacokinetics of insulin lispro in healthy volunteers or patients with diabetes mellitus. A few of the studies used patients with diabetes mellitus in multicenter, randomized, crossover trials of insulin lispro.

DATA EXTRACTION

All clinical trials that were available prior to submission of this manuscript for publication, including unpublished reports, were reviewed.

DATA SYNTHESIS

The human insulin analog, insulin lispro, which is biosynthetically made by inverting the amino acid sequence of human insulin at B-28 and B-29, is more effective than regular human insulin in improving postprandial glucose control. Subcutaneous injections of insulin lispro result in decreased blood glucose peaks following meals and a potential decreased risk of hypoglycemic episodes, including nighttime hypoglycemia in patients with type 1 diabetes. Insulin lispro in comparison with regular human insulin provides equal or slightly better blood glucose control. When compared with subcutaneous injections of regular human insulin, the peak serum insulin concentration of insulin lispro is three times higher, time to peak is 4.2 times faster, the absorption rate constant is double, and the duration of action is half as long. Insulin lispro is similar to regular human insulin with reference to dose, toxicity, adverse effects, drug interactions, and immunogenicity. When insulin lispro is mixed with human NPH (isophane) or Lente insulins, insulin lispro should be drawn into the syringe first, mixed with the long-acting insulin, and injected immediately after mixing. Patients using insulin lispro perceive an improvement in their well-being and quality of life due to flexible injection times and less frequent hypoglycemic reactions. Insulin lispro is believed to be suitable for patients using insulin infusion pumps.

CONCLUSIONS

Insulin lispro is equipotent to human insulin and has a much more rapid onset and shorter duration of action than human insulin does, which may reduce the risk of hypoglycemia. In addition, insulin lispro improves the dosing convenience for patients with diabetes and provides a more natural control of blood glucose concentrations. Insulin lispro is a useful new agent in the treatment of diabetes mellitus.