© 2004 by the American Diabetes Association, Inc.
Insulin Glulisine Provides Improved Glycemic Control in Patients With Type 2 Diabetes
1 Scripps Clinic, La Jolla, California Address correspondence and reprint requests to George Dailey, MD, Scripps Clinic, 10666 North Torrey Pines Rd., La Jolla, CA 92037. E-mail: dailey.george{at}scrippshealth.org
OBJECTIVEInsulin glulisine is a novel analog of human insulin designed for use as a rapid-acting insulin. This study compared the safety and efficacy of glulisine with regular human insulin (RHI) in combination with NPH insulin. RESEARCH DESIGN AND METHODSIn total, 876 relatively well-controlled patients with type 2 diabetes (mean HbA1c 7.55%) were randomized and treated with glulisine/NPH (n = 435) or RHI/NPH (n = 441) for up to 26 weeks in this randomized, multicenter, multinational, open-label, parallel-group study. Subjects were allowed to continue the same dose of prestudy regimens of oral antidiabetic agent (OAD) therapy (unless hypoglycemia necessitated a dose change). RESULTSA slightly greater reduction from baseline to end point of HbA1c was seen in the glulisine group versus RHI (0.46 vs. 0.30% with RHI; P = 0.0029). Also, at end point, lower postbreakfast (156 vs. 162 mg/dl [8.66 vs. 9.02 mmol/l]; P < 0.05) and postdinner (154 vs. 163 mg/dl [8.54 vs. 9.05 mmol/l]; P < 0.05) blood glucose levels were noted. Symptomatic hypoglycemia (overall, nocturnal, and severe) and weight gain were comparable between the two treatment groups. There were no between-group differences in baseline-to-end point changes in insulin dose. CONCLUSIONSTwice-daily glulisine associated with NPH can provide small improvements in glycemic control compared with RHI in patients with type 2 diabetes who are already relatively well controlled on insulin alone or insulin plus OADs. The clinical relevance of such a difference remains to be established.
Abbreviations: ITT, intention to treat OAD, oral antidiabetic agent RHI, regular human insulin TEAE, treatment-emergent adverse event
Attaining and maintaining normoglycemic control are the treatment goals in type 2 diabetes in order to minimize long-term clinical risk (1). Although oral antidiabetic agents (OADs) may initially control hyperglycemia, most patients with type 2 diabetes will ultimately require insulin therapy, as ß-cell function progressively declines (2,3). Ideally, glycemic control in insulin-treated patients should mimic physiologic insulin secretion, thereby maintaining levels as close to normoglycemia as possible at all times. Hence, there should be appropriate prandial replacement of the peaks in insulin activity to complement continuous 24-h basal insulin levels. Regular human insulin (RHI) has been used as a mealtime therapy for many years. However, its onset of action is relatively slow and the action profile does not closely mimic physiologic mealtime insulin secretion, necessitating its recommended administration 3045 min before meals (4). This requires meal planning that can be restrictive to patients lifestyles; indeed, most patients administer RHI <30 min before mealtime (5). RHI is, therefore, unlikely to provide optimal glycemic control in most patients. Glulisine is a novel rapid-acting insulin analog that differs from human insulin by the replacement of the amino acid asparagine with lysine at position 3 and lysine with glutamic acid at position 29 of the B-chain. Compared with RHI, glulisine has a more rapid onset of action and a shorter duration of action (6). The time-action profile of glulisine thus lends itself to greater treatment convenience compared with RHI, as its use requires less mealtime planning. This study compared the effects of glulisine (Aventis Pharma) and RHI (Eli Lilly) on HbA1c, self-monitored blood glucose profiles, hypoglycemia, and safety in patients with type 2 diabetes.
Subjects with established type 2 diabetes, aged 18 years, who had been on insulin therapy for 6 months before the study, with an HbA1c level between 6.0 and 11.0%, were enrolled in the study. This was a phase III, 1:1 randomized, multicenter, multinational, controlled, open-label, parallel-group study with a 1-week screening, 4-week run-in, and 26-week treatment phase. During run-in, all subjects received RHI and NPH insulin injections, both given twice daily. The study was conducted in accordance with Good Clinical Practice and conformed to the ethical principles of the Declaration of Helsinki. All study materials were reviewed and approved by an independent ethics committee or institutional review board. Randomization was stratified according to whether subjects were treated with OADs at randomization. Subjects were randomized to subcutaneous injections of glulisine or RHI 015 and 3045 min, respectively, before breakfast and dinner. If required, based on the clinical judgment of the investigator, more than two injections of glulisine or RHI were permitted. Both treatment groups received twice-daily injections of NPH insulin as basal therapy. The number of meal time insulin injections and the timing of NPH insulin administration were established during run-in and maintained during the treatment phase. Mixing of glulisine or RHI with NPH insulin just before injection was allowed. No formal insulin dose algorithms were given. Adjustment of glulisine and RHI doses was at the investigators discretion if necessary to achieve 2-h postprandial blood glucose 120160 mg/dl (6.78.9 mmol/l), while avoiding hypoglycemia. NPH insulin doses were adjusted according to a predefined insulin titration regimen to achieve preprandial blood glucose 90120 mg/dl (5.06.7 mmol/l), while avoiding hypoglycemia. Continuation of prestudy OAD dose and regimen was permitted, unless hypoglycemia necessitated a dose reduction for safety reasons.
Glycemic control parameters
Self-monitored blood glucose profiles.
Hypoglycemia
Insulin dose
Safety
Statistical methods
A total of 1,186 patients entered screening; 878 were randomized and 876 received study medication (glulisine: n = 435; RHI: n = 441). This comprised the ITT population. Of the 876 treated patients, 64 withdrew (glulisine: n = 28; RHI: n = 36) after treatment start. Main reasons for withdrawal included did not wish to continue (glulisine: n = 12; RHI: n = 13), lost to follow-up (glulisine: n = 5; RHI: n = 6), and TEAEs (glulisine: n = 5; RHI: n = 6). Baseline characteristics (Table 1) were similar between the two treatment groups, except for age and duration of diabetes. Patients randomized to glulisine were older (mean age 58.9 ± 10.20 years vs. 57.7 ± 9.90 with RHI; P = 0.04) and had a significantly longer mean duration of diabetes versus the RHI group (14.7 ± 8.12 vs. 13.4 ± 7.55 years; P = 0.02). The majority of subjects in the glulisine and RHI treatment groups used NPH insulin before entry into the study (388 [89.2%] and 386 [87.5%] subjects, respectively). Before the study, premixed insulin was being used by 169 (38.9%) patients in the glulisine group and 169 (38.3%) subjects in the RHI group.
Glycemic control Baseline to end point change in HbA1c. Baseline HbA1c was comparable between the treatment groups (Table 1), and both groups showed significant baseline to end point reductions in mean HbA1c levels (0.46 and 0.30%, for glulisine and RHI, respectively). Noninferiority of glulisine compared with RHI was demonstrated by virtue of the fact that the upper bound of the 95% CI was <0.4% (baseline-adjusted mean difference 0.16, 95% CI 0.26 to 0.05). The upper limit of the 95% CI was <0.0%, which established statistical superiority for glulisine (P = 0.0029). In both groups, just over one-half of the patients reached HbA1c 7% (53.5 and 50.6% of patients on glulisine and RHI, respectively).
Change in HbA1c over the course of the study.
Self-monitored blood glucose profile. At baseline, self-monitored seven-point blood glucose profiles were comparable in the two groups. However, blood glucose values were lower with glulisine versus RHI at all on-treatment points, with statistical significance reached at 2 h postbreakfast and 2 h postdinner (P < 0.05) (Fig. 2).
Symptomatic hypoglycemia There were no statistically significant between-treatment differences in the incidences or monthly rates of overall, nocturnal, or severe symptomatic hypoglycemia from month 4 to treatment end, a time at which patients were fully acclimated to the study. In both the glulisine and RHI groups, a similar proportion of patients experienced at least one episode of symptomatic (51.7 vs. 53.6%, respectively; P = 0.600), nocturnal (21.4 vs. 24.5%, respectively; P = 0.303), or severe hypoglycemia (1.4 vs. 1.2%, respectively; P = 0.645). Symptomatic hypoglycemia rates were similar in the insulin glulisine and RHI groups (0.95 vs. 1.04 events/patient-month, respectively; P = 0.186), as were nocturnal hypoglycemia rates (0.14 vs. 0.21 events/patient-month, respectively; P = 0.109). Severe hypoglycemia rates were low at 0.0041 events/patient-month for glulisine and 0.0037 events/patient-month for RHI, and similar between treatment groups (between-treatment P = 0.353). This between-treatment similarity was consistent over the entire treatment period (data not shown).
Insulin dose A total of 78.7% of patients reported mixing the short-acting insulin with NPH insulin (glulisine: 74.1%; RHI: 83.1%) before injection by syringe; 25.7% mixed their insulins once daily and 53.0% mixed twice daily. The proportion of patients mixing the insulins in a syringe once and twice daily was similar in the two treatment groups.
OAD use
Safety
Laboratory and other safety data.
Insulin antibodies
This is the largest study described to date that compares a rapid-acting insulin analog with RHI in patients with type 2 diabetes. There is a growing trend in the diabetes community toward reaching ever more normoglycemic control (7,8). Consequently, the inadequate glycemic control achieved historically by patients with type 2 diabetes is becoming increasingly unacceptable. There is no doubt that the addition of basal insulin to ongoing OAD therapy, particularly in treat-to-target insulin titration regimens, significantly improves glycemic control in most patients; however, some patients may remain suboptimally controlled (9). It is through the control of postprandial hyperglycemia using short-acting insulin at mealtimes that the best levels of glycemic control will be achieved in patients with type 2 diabetes. In addition to the benefits of controlling postprandial excursions, it is becoming increasingly apparent that postprandial hyperglycemia may be an important predictor of cardiovascular mortality from an epidemiologic standpoint (10). In addition, recent evidence demonstrates that in patients with type 2 diabetes on oral agents and on no insulin treatment, the relative contribution of postprandial glucose is more relevant in the lowest quintiles of HbA1c (11). In light of this evidence, it is important to maximize postprandial glycemic control and evaluate any new short-acting insulin designed to do this in patients with type 2 diabetes.
The purpose of this study was to compare the efficacy and safety of glulisine with RHI in patients with type 2 diabetes. The study was designed to reflect real-world clinical practice as much as possible by allowing patients to continue with prestudy OAD regimens. The study included The greater baseline to end point reduction in HbA1c observed with glulisine versus RHI in this study was small and statistically significant, although the clinical relevance of such a difference remains to be established. Such a difference has not been observed previously in type 2 diabetic patients in studies with other rapid-acting insulin analogs (although significant reductions in the incidence of hypoglycemia versus RHI have been observed with other short-acting insulin analogs) (12). Certain aspects of the study design may have contributed to the observed between-treatment difference in baseline to end point change in HbA1c. The open-label design could have introduced bias in favor of the newer study treatment; however, this type of open-label design has been, and remains, a necessity with any study comparing a rapid-acting insulin analog with RHI because of the considerable differences in the timing of the administration of these two types of insulin. In this study, attempts were made to reduce treatment bias through measurement of HbA1c at a central laboratory and blinding investigators to these centrally measured HbA1c levels until databases were locked after the study end. The large sample size of the study may also account, in part, for a determination of statistical significance for a difference that is of unclear clinical relevance at this time. Any between-treatment differences in glycemic control were not a result of increased short-acting, basal, or total insulin doses; OAD usage; or the number of insulin injections per day. Published studies (13,14) with other rapid-acting insulin analogs in combination with NPH insulin in type 1 diabetes suggest that these analogs may require greater basal insulin supplementation compared with RHI even to maintain equivalent levels of glycemic control. It is noteworthy that the patients included in this study were considerably overweight; the mean BMI was >34 kg/m2 in both groups. Most published studies of the pharmacokinetics and pharmacodynamics of rapid-acting insulin analogs have been in lean healthy subjects or patients with type 1 diabetes. Thus, there are little published data on the pharmacokinetics and pharmacodynamics of these agents in type 2 diabetic patients, the vast majority of whom are overweight. Studies are currently underway to evaluate the activity of glulisine in obese individuals. In conclusion, this is the largest study to date evaluating the use of a rapid-acting insulin analog in patients with type 2 diabetes in a multiple insulin injection regimen. The results demonstrate that glulisine, which offers greater treatment convenience due to its time-action profile, provides small and statistically significant improvements in glycemic control (which remain to be proven clinically relevant) compared with RHI. Glulisine, therefore, may prove a valuable addition to the armamentarium of therapeutic tools for the management of diabetes.
The investigators of the HMR1964/3002 Study Group U.S. D.A. Bell, S.O. Bookin, P. Boyle, P. Bressler, V. Broadstone, L. Chaykin, G. Dailey, S. Davis, J. Desemone, A. Dwarkanathan, M. Farooqi, M. Feinglos, J. Felicetta, R. Fink, V. Fonseca, S. Garg, J. Gilbert, G. Grunberger, R.A. Guthrie, M. Henderson, K. Hershon, L. Isley, R.K. Jain, R. Juneja, R. Kaplan, H. Katzeff, D.S. Kayne, L.J. Klaff, T. Knecht, P. Koenig, D. Kumar, R. Lang, P. Levy, D. Lorber, J. Dostou, M. Magee, M. McClanahan, J. McGill, A. Mehta, M. Meredith, J. Mersey, S. Miller, P. Peters, P. Raskin, M. Reeves, P. Reith, M. Rendell, R. Reynolds, S. Richardson, V. Roberts, J. Rosenstock, S. Schwartz, T. Sherradon, S. Rubens, N.G. Soler, B. Spinowitz, R. Tanenberg, S. Thomson, T. Wahl, R. Weinstock, S. Werbel, K. Wietecha, J. Williams, C.H. Wysham, and D. Streja.
Canada.
Australia.
G.D. has received honoraria, research grants, and served as an occasional consultant for Aventis, Bristol-Myers Squibb, Merck, Novo Nordisk, Pfizer, Eli Lilly, GlaxoSmithKline, and Amylin; has served on a speakers bureau only for Merck Sante; and has been an investigator for Schering-Plough, Takeda, Kowa, ACON, Forest, and Becton-Dickinson. J.R. has served as a consultant and/or on a speakers bureau for Aventis, Pfizer, Novo Nordisk, Takeda, GlaxoSmithKline, and Johnson & Johnson; and has received research support from Bristol-Myers Squibb, GlaxoSmithKline, Eli Lilly, Novo Nordisk, Pfizer, Aventis, Novartis, Takeda, AstraZeneca, and Merck. K.W. holds stock in Bristol-Myers Squibb and Lilly. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. Received for publication January 22, 2004. Accepted for publication July 19, 2004.
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