Basal insulin analogues in the management of diabetes mellitus: What progress have we made?

Modern basal insulin analogs: An incomplete story

The currently available basal insulin does not completely mimic the endogenous insulin secretion. This has continued to promote the search for ideal basal insulin. The newer basal insulin have primarily focused on increasing the duration of action, reducing variability, and reducing the incidence of hypoglycemia, particularly nocturnal. However, the changing criteria of hypoglycemia within a short span of a few years along with the surprising introduction of major cardiac events as another outcome measure has not only clouded the assessment of basal insulin but has also polarized opinion worldwide about the utility of the newer basal insulin. A critical review of both the pre and post FDA analysis of all the basal insulin in this article attempts to clear some of the confusion surrounding the issues of hypoglycemia and glycemic control. This article also discusses all the trials and meta-analysis done on all the current basal insulin available along with their head-to-head comparison with particular attention to glycemic control and hypoglycemic events including severe and nocturnal hypoglycemia. This in-depth analysis hopes to provide a clear interpretation of the various analyses available in literature at this point of time thereby acting as an excellent guide to the readers in choosing the most appropriate basal insulin for their patient.

U300, a novel long-acting insulin formulation

INTRODUCTION

Insulin glargine (100 U/ml; U100) was the first long-acting basal insulin analog to be introduced into clinical practice and it remains the most widely used. Although U100 is an effective and safe treatment, research is ongoing to optimize the time-action profile. The focus of this review is insulin glargine [rDNA origin] injection 300 U/ml (U300), a novel formulation that contains a higher concentration of insulin than U100.

AREAS COVERED

The clinical efficacy and safety of U300 in patients with type 1 and type 2 diabetes mellitus are discussed, with an emphasis on recently released data from the Phase III EDITION clinical trials.

EXPERT OPINION

The higher concentration of insulin in U300 results in a distinct pharmacokinetic and pharmacodynamic profile. U300 has a longer duration of action than U100 and plasma insulin exposure is less variable. Both insulin formulations exhibit a similar efficacy and safety profile, but importantly, U300 is associated with less body weight gain and a lower incidence of hypoglycaemic events.

Old and new basal insulin formulations: understanding pharmacodynamics is still relevant in clinical practice

Long-acting insulin analogues have been developed to mimic the physiology of basal insulin secretion more closely than human insulin formulations (Neutral Protamine Hagedorn, NPH). However, the clinical evidence in favour of analogues is still controversial. Although their major benefit as compared with NPH is a reduction in the hypoglycaemia risk, some cost/effectiveness analyses have not been favourable to analogues, largely because of their higher price. Nevertheless, these new formulations have conquered the insulin market. Human insulin represents currently no more than 20% of market share. Despite (in fact because of) the widespread use of insulin analogues it remains critical to analyse the pharmacodynamics (PD) of basal insulin formulations appropriately to interpret the results of clinical trials correctly. Importantly, these data may help physicians in tailoring insulin therapy to patients' individual needs and, additionally, when clinical evidence is not available, to optimize insulin treatment. For patients at low risk for/from hypoglycaemia, it might be acceptable and also cost-effective not to use long-acting insulin analogues as basal insulin replacement. Conversely, in patients with a higher degree of insulin deficiency and increased risk for hypoglycaemia, analogues are the best option due to their more physiological profile, as has been shown in PD and clinical studies. From this perspective optimizing basal insulin treatment, especially in type 2 diabetes patients who are less prone to hypoglycaemia, would be suitable making significant resources available for other relevant aspects of diabetes care.

The development of new basal insulins: is there any clinical advantage with their use in type 2 diabetes?

INTRODUCTION

The basal insulin products currently on market do not optimally mimic endogenous insulin secretion. These unmet clinical needs have fueled the development of new basal insulin analogues for improving their pharmacokinetics/pharmacodynamics profile.

AREAS COVERED

We review the recent literature investigating the efficacy and safety of new basal insulin analogues in type 2 diabetes, as in the USA, insulin utilization accounted for 26% of treatment visits for these patients in 2012. Insulin degludec is a desB30 insulin acylated at the LysB29 residue with a glutamate linker and 16-carbon fatty diacyl side chain. Insulin lispro has been PEGylated at lysine B28, via a urethane bond, which increases the hydrodynamic size of the molecule and reduces its absorption and clearance following subcutaneous administration. Glargine U300 represents a new high-strength glargine formulation (300 U/ml): once injected, U300 forms a compact subcutaneous depot with a smaller surface area to produce a more gradual and prolonged release. Both PEG-lispro and glargine U300 are not yet on the market.

EXPERT OPINION

Ultra-long acting and high-strength formulations of new basal analogues have the potential for less glycemic variability, less (nocturnal) hypoglycemia and weight-loss advantage for PEG-lispro. However, these new basal insulin analogues need to be monitored closely for adverse signals.