Diabetes Technology Meeting 2023.

Diabetes Technology Society hosted its annual Diabetes Technology Meeting from November 1 to November 4, 2023. Meeting topics included digital health; metrics of glycemia; the integration of glucose and insulin data into the electronic health record; technologies for insulin pumps, blood glucose monitors, and continuous glucose monitors; diabetes drugs and analytes; skin physiology; regulation of diabetes devices and drugs; and data science, artificial intelligence, and machine learning. A live demonstration of a personalized carbohydrate dispenser for people with diabetes was presented.

NIH Fifth Artificial Pancreas Workshop 2023: Meeting Report: The Fifth Artificial Pancreas Workshop: Enabling Fully Automation, Access, and Adoption.

The Fifth Artificial Pancreas Workshop: Enabling Fully Automation, Access, and Adoption was held at the National Institutes of Health (NIH) Campus in Bethesda, Maryland on May 1 to 2, 2023. The organizing Committee included representatives of NIH, the US Food and Drug Administration (FDA), Diabetes Technology Society, Juvenile Diabetes Research Foundation (JDRF), and the Leona M. and Harry B. Helmsley Charitable Trust. In previous years, the NIH Division of Diabetes, Endocrinology, and Metabolic Diseases along with other diabetes organizations had organized periodic workshops, and it had been seven years since the NIH hosted the Fourth Artificial Pancreas in July 2016. Since then, significant improvements in insulin delivery have occurred. Several automated insulin delivery (AID) systems are now commercially available. The workshop featured sessions on: (1) Lessons Learned from Recent Advanced Clinical Trials and Real-World Data Analysis, (2) Interoperability, Data Management, Integration of Systems, and Cybersecurity, Challenges and Regulatory Considerations, (3) Adaptation of Systems Through the Lifespan and Special Populations: Are Specific Algorithms Needed, (4) Development of Adaptive Algorithms for Insulin Only and for Multihormonal Systems or Combination with Adjuvant Therapies and Drugs: Clinical Expected Outcomes and Public Health Impact, (5) Novel Artificial Intelligence Strategies to Develop Smarter, More Automated, Personalized Diabetes Management Systems, (6) Novel Sensing Strategies, Hormone Formulations and Delivery to Optimize Close-loop Systems, (7) Special Topic: Clinical and Real-world Viability of IP-IP Systems. "Fully automated closed-loop insulin delivery using the IP route," (8) Round-table Panel: Closed-loop performance: What to Expect and What are the Best Metrics to Assess it, and (9) Round-table Discussion: What is Needed for More Adaptable, Accessible, and Usable Future Generation of Systems? How to Promote Equitable Innovation? This article summarizes the discussions of the Workshop.

Progressive Acceleration of Insulin Exposure Over 7 Days of Infusion Set Wear.

Insulin exposure varies over 3 days of insulin infusion set (IIS) wear making day-to-day insulin dosing challenging for people with diabetes (PWD). Here we report insulin pharmacodynamic (PD) and pharmacokinetic (PK) data extending these observations to 7 days of IIS wear. PWD (A1C ≤8.5%, C-peptide <0.6 nmol/L, ≥6 months pump use) were enrolled in a crossover euglycemic clamp pilot study comparing conventional Teflon angled IISs with an investigational extended-wear IIS. PK/PD data from six participants were obtained for 5 h postbolus. Although PD data were unstable, PK profiles (pooled data from both groups) of insulin lispro (0.15 U/kg bolus) showed statistically significant progressive decreases from days 0 to 7 for tmax (P < 0.001), Cmax (P < 0.05), and mean residence time (P < 0.0001). Area under the insulin concentration curve (AUC0-300) declined by ∼24% from days 0 to 7 (P < 0.05). These results confirm/extend previous observations showing progressive acceleration of insulin exposure over IIS wear time. This may have implications for PWD and designers of closed-loop algorithms, although larger studies are necessary to confirm this. The study was registered in clinicaltrials.gov (NCT04398030).

Reduced hypoglycaemia using liver-targeted insulin in individuals with type 1 diabetes.

AIM: To investigate whether an increased bolus: basal insulin ratio (BBR) with liver-targeted bolus insulin (BoI) would increase BoI use and decrease hypoglycaemic events (HEv). PATIENT POPULATION AND METHODS: We enrolled 52 persons (HbA1c 6.9% ± 0.12%, mean ± SEM) with type 1 diabetes using multiple daily injections. Hepatic-directed vesicle (HDV) was used to deliver 1% of peripheral injected BoI to the liver. A 90-day run-in period was used to introduce subjects to unblinded continuous glucose monitoring and optimize standard basal insulin (BaI) (degludec) and BoI (lispro) dosing. At 90 days, BoI was changed to HDV-insulin lispro and subjects were randomized to an immediate 10% or 40% decrease in BaI dose. RESULTS: At 90 days postrandomization, total insulin dosing was increased by ~7% in both cohorts. The -10% and -40% BaI cohorts were on 7.7% and 13% greater BoI with 6.9% and 30% (P = .02) increases in BBR, respectively. Compared with baseline at randomization, nocturnal level 2 HEv were reduced by 21% and 43%, with 54% and 59% reductions in patient-reported HEv in the -10% and -40% BaI cohorts, respectively. CONCLUSIONS: Our study shows that liver-targeted BoI safely decreases HEv and symptoms without compromising glucose control. We further show that with initiation of liver-targeted BoI, the BBR can be safely increased by significantly lowering BaI dosing, leading to greater BoI usage.

Feasibility study of a prototype extended-wear insulin infusion set in adults with type 1 diabetes.

AIM: To assess the feasibility of a prototype insulin infusion set (IIS) for extended wear in adults with type 1 diabetes. MATERIALS AND METHODS: The prototype Capillary Biomedical investigational extended-wear IIS (CBX IIS) incorporates a soft, flexible, reinforced kink-resistant angled nylon-derivative cannula with one distal and three proximal ports to optimize insulin delivery. Twenty adult participants with type 1 diabetes established on insulin pump therapy used the CBX IIS for two 7-day test periods while wearing a Dexcom G5 continuous glucose monitor. RESULTS: Participants were able to wear the CBX IIS for an average of 6.6 ± 1.4 days. Eighty-eight percent (36 of 41) of sets were worn for 7 days. No serious adverse events were reported. Five infusion sets failed prematurely because of: unresolvable hyperglycaemia (three); hyperglycaemia with elevated ketones (one); or infection (one). Median time in range (3.9-10.0 mmol/L) was 62% (54-76). Average glucose levels per day of infusion set wear showed a statistically significant increase over time (p < .001). CONCLUSIONS: Our preliminary observations confirm the tolerability of the prototype CBX IIS for extended wear, albeit with a deterioration in glucose control after the third day.

Divergent Hypoglycemic Effects of Hepatic-Directed Prandial Insulin: A 6-Month Phase 2b Study in Type 1 Diabetes.

OBJECTIVE: Hepatic-directed vesicle insulin (HDV) uses a hepatocyte-targeting moiety passively attaching free insulin, improving subcutaneous insulin's hepatic biodistribution. We assessed HDV-insulin lispro (HDV-L) versus insulin lispro (LIS) in type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: Insulin Liver Effect (ISLE-1) was a 26-week, phase 2b, multicenter, randomized, double-blind, noninferiority trial. RESULTS: Among 176 randomized participants (HDV-L n = 118, LIS n = 58), the difference in change from baseline A1C was 0.09% (95% CI -0.18% to 0.35%), confirming noninferiority (prespecified margin ≤0.4%). Overall, there were no statistically significant differences between treatments for hypoglycemia or insulin dosing. However, baseline A1C modified the treatment group effect (interaction P < 0.001) on clinically apparent hypoglycemia designated by treatment-blinded investigators as severe. Thus, at higher baseline A1C, there was less hypoglycemia and lower insulin dosing with similar A1C outcomes during HDV-L versus LIS, whereas greater risk of hypoglycemia despite similar A1C outcomes and insulin doses was observed with lower baseline A1C. Among poorly controlled participants (A1C ≥8.5%), incidence rates of severe hypoglycemia in the HDV-L and LIS arms were 69 and 97 events/100 person-years, respectively (P = 0.03), whereas with A1C <8.5%, respective rates were 191 and 21 events/100 person-years (P = 0.001). Similar A1C-dependent trends in hypoglycemia were seen with continuous glucose monitoring. Among poorly controlled participants, bolus insulin doses at end point were ∼25% lower with HDV-L (P = 0.02), despite similar A1C outcomes; in better-controlled participants, insulin doses and A1Cs were stable over time in both subgroups. No safety signals were identified. CONCLUSIONS: Hepatic biodistribution of HDV-L appears to potentiate insulin effect in T1D, with divergent clinical outcomes in hypoglycemia dependent on baseline A1C.

Recombinant Human PH20: Baseline Analysis of the Reactive Antibody Prevalence in the General Population Using Healthy Subjects.

BACKGROUND: Recombinant human PH20 (rHuPH20) is used to depolymerize hyaluronan in the subcutaneous space, increasing the dispersion and absorption of co-administered drugs. While ~ 5 to 10% of rHuPH20 treatment-naïve healthy volunteers have demonstrated rHuPH20-reactive antibodies, associations with age, sex, fertility, and immune disorders remain unknown. OBJECTIVES: Using demographically diverse healthy volunteers, we assessed the prevalence of rHuPH20-reactive antibodies in the general population and potential associations with fertility and autoimmunity diseases. METHODS: In total, 896 subjects aged ≥ 12 years (767 adults; 129 children) without prior exposure to rHuPH20 were enrolled. A demographic and limited medical history review was performed, and K3-EDTA-anticoagulated plasma was analyzed for rHuPH20-reactive antibodies using a bridging immunoassay. RESULTS: Adult and pediatric positivity rates for rHuPH20-reactive antibodies were 5.2% (40/767) and 1.6% (2/129), respectively. Titers ranged from 5 to 2560 (median 30). In five antibody-positive subjects from whom repeated samples were available, antibody titers remained unchanged or decreased fourfold over periods up to 590 days. The prevalence of rHuPH20-reactive antibodies significantly increased with age (p = 0.0006) and was significantly higher in males than in females (p = 0.0010). Men who had fathered children had a significantly increased prevalence of rHuPH20-reactive antibodies than men who had not (p = 0.0036), whereas the rate of childbearing was not significantly different between rHuPH20 antibody-positive and -negative women. The prevalence between racial/ethnic groups was not significantly different, nor was the presence/absence of an autoimmune disorder. CONCLUSIONS: Approximately 1/20 of the adult population had rHuPH20-reactive antibodies. The reason remains unknown; however, no evidence for a negative effect on fertility or association with autoimmune disease was demonstrated.

Pump Users Clamor for Faster Insulin: Is Fast-Acting Insulin Aspart Ready for Them?

Recently approved in Europe, Canada, and the United States, fast-acting insulin aspart (FIASP®) is a new rapid acting insulin. Approved for subcutaneous or IV injection use, there is little data available regarding the clinical utility of FIASP in insulin pumps. The article by Zijlstra and colleagues in this issue begins to close this gap by testing pump compatibility of FIASP in the clinic. Reporting on a small (37 subjects) and short (6 weeks) study looking at aspects of infusion set propensity for clogging and malfunction, no cases of infusion set plugging in either FIASP (25 subjects) or insulin aspart (12 subjects) were seen. Unexplained hyperglycemia and premature infusion set changes were more common with FIASP than with insulin aspart. This study demonstrated sufficient safety and efficacy of FIASP in the pump setting to pave the way for longer, larger and more definitive clinical trials.

The Need for Faster Insulin.

Considerable progress in treatment of diabetes has been made in the nearly 100 years following the discovery of insulin, and advances in insulin therapy have improved convenience, quality of life, overall glycemic control (A1C), and risk of hypoglycemia. An unmet need remains for a mealtime insulin that can faithfully reproduce the metabolic profile that ensues following meal ingestion in healthy persons. A number of "ultra-fast" insulin programs have been initiated, and Afrezza® (insulin human; Inhalation Powder, MannKind Corporation, Danbury, CT) stands as the first such product to be approved by the US FDA. Afrezza is unique as an "ultra-ultra" fast insulin, faster than any other entrant except IV insulin. The benefits and limitations of the Afrezza profile are discussed in this analysis.

Hypoglycemia evaluation and reporting in diabetes: Importance for the development of new therapies.

Hypoglycemia complicating diabetes therapy is well recognized to be an ever-present threat to patients, their families, providers, payers, and regulators. Despite this being widely acknowledged, the regulatory stance on hypoglycemia as an endpoint in clinical trials to support new product registration has not evolved in any meaningful way since the publication of a position paper by an American Diabetes Association (ADA) Workgroup in 2005. As the impact of hypoglycemia on persons affected by diabetes is of major importance when assessing new treatments, the historical position of regulatory agencies on hypoglycemia is reviewed with respect to product approvals. The purpose of this article is to present proposals for facilitating development of therapies that reduce hypoglycemia risk through (1) development of composite measures of benefit for regulatory endpoints and (2) facilitation of the fulfillment of an unmet clinical need for reducing hypoglycemia. In view of greater comprehension of the effects of hypoglycemia, coupled with improved methodology to assess its frequency, the authors recommend: (1) a numerical cut point of <54 mg/dl (<3.0 mmol/L) as a clinically relevant level with which to define meaningful hypoglycemia for trials of diabetes therapies; (2) utilization in clinical trials of mature glucose monitoring technologies for purposes of regulatory evaluation and clinical decision-making; and (3) development of primary efficacy endpoint composites that include hypoglycemia rates and glycemic control.

Clinical Immunogenicity of rHuPH20, a Hyaluronidase Enabling Subcutaneous Drug Administration.

Recombinant human PH20 hyaluronidase (rHuPH20) is used to facilitate dispersion of subcutaneously delivered fluids and drugs. This report summarizes rHuPH20 immunogenicity findings from clinical trials where rHuPH20 was co-administered with SC human immunoglobulin, trastuzumab, rituximab, or insulin. Plasma samples were obtained from evaluable subjects participating in ten different clinical trials as well as from healthy plasma donors. A bridging immunoassay and a modified hyaluronidase activity assay were used to determine rHuPH20-reactive antibody titers and neutralizing antibodies, respectively. rHuPH20-binding antibody populations from selected subjects with positive titers were affinity-purified and subjected to further characterization such as cross-reactivity with endogenous PH20. Among individual trials, the prevalence of pre-existing rHuPH20-reactive antibodies varied between 3 and 12%, excepting the primary immunodeficiency (PID) studies. Incidence of treatment-induced rHuPH20 antibodies was 2 to 18%, with the highest titers (81,920) observed in PID. No neutralizing antibodies were observed. Within most trials, the kinetics of antibody responses were comparable between pre-existing and treatment-induced antibody responses, although responses classified as persistent were more common in subjects with pre-existing titers. There was no association between antibody positivity and either local or systemic adverse events. Pre-existing and treatment-induced antibody populations were of similar immunoglobulin isotypes and cross-reacted to endogenous PH20 to similar extents. No cross-reactivity to PH20 paralogs was detected. rHuPH20 induces only modest immunogenicity which has no association with adverse events. In addition, antibodies purified from baseline-positive individuals are qualitatively similar to those purified from individuals developing rHuPH20-reactive antibodies following exposure to the enzyme.

Comparative pharmacokinetics and insulin action for three rapid-acting insulin analogs injected subcutaneously with and without hyaluronidase.

OBJECTIVE: To compare the pharmacokinetics and glucodynamics of three rapid-acting insulin analogs (aspart, glulisine, and lispro) injected subcutaneously with or without recombinant human hyaluronidase (rHuPH20). RESEARCH DESIGN AND METHODS: This double-blind six-way crossover euglycemic glucose clamp study was conducted in 14 healthy volunteers. Each analog was injected subcutaneously (0.15 units/kg) with or without rHuPH20. RESULTS: The commercial formulations had comparable insulin time-exposure and time-action profiles as follows: 50% exposure at 123-131 min and 50% total glucose infused at 183-186 min. With rHuPH20, the analogs had faster yet still comparable profiles: 50% exposure at 71-79 min and 50% glucose infused at 127-140 min. The accelerated absorption with rHuPH20 led to twice the exposure in the first hour and half the exposure beyond 2 h, which resulted in 13- to 25-min faster onset and 40- to 49-min shorter mean duration of insulin action. CONCLUSIONS: Coinjection of rHuPH20 with rapid-acting analogs accelerated insulin exposure, producing an ultra-rapid time-action profile with a faster onset and shorter duration of insulin action.

Ultrafast-acting insulins: state of the art.

Optimal coverage of prandial insulin requirements remains an elusive goal. The invention of rapid-acting insulin analogs (RAIAs) was a big step forward in reducing postprandial glycemic excursions in patients with diabetes in comparison with using regular human insulin; however, even with these, the physiological situation cannot be adequately mimicked. Developing ultrafast-acting insulins (UFIs)-showing an even more rapid onset of action and a shorter duration of action after subcutaneous (SC) administration-is another step forward in achieving this goal. The need for UFIs has been gradually recognized over the years, and subsequently, a number of different approaches to cover this need are in clinical development. A rapid increase in circulating insulin levels can be achieved by different measures: modification of the primary structure of insulin molecule (as we know from RAIAs), addition of excipients that enhance the appearance in the monomeric state post-injection, or addition of enzymes that enable more free spreading of the insulin molecules in the SC tissue. Other measures to increase the insulin absorption rate increase the local blood flow nearby the insulin depot in the SC tissue, injecting the insulin intradermally or applying via another route, e.g., the lung. The development of these approaches is in different stages, from quite early stages to nearing market authorization. In time, daily practice will show if the introduction of UFIs will fulfill their clinical promise. In this review, the basic idea for UFIs will be presented and the different approaches will be briefly characterized.

Accelerating and improving the consistency of rapid-acting analog insulin absorption and action for both subcutaneous injection and continuous subcutaneous infusion using recombinant human hyaluronidase.

Rapid-acting insulin analogs were introduced to the market in the 1990s, and these products have improved treatment of diabetes by shortening the optimum delay time between injections and meals. Compared with regular human insulin, rapid-acting insulin formulations also reduce postprandial glycemic excursions while decreasing risk of hypoglycemia. However, the current prandial products are not fast enough for optimum convenience or control. Recombinant human hyaluronidase (rHuPH20) has been used to increase the dispersion and absorption of other injected drugs, and in the case of prandial insulin analogs, it confers both ultrafast absorption and action profiles. Animal toxicology studies have demonstrated excellent tolerability of rHuPH20, and human studies, involving over 60,000 injections of prandial insulin + rHuPH20 to date, have similarly shown excellent safety and tolerability. Studies using rapid-acting analog insulin with rHuPH20 have included clinic-based pharmacokinetic and glucodynamic euglycemic glucose clamp studies, test meal studies, and take-home treatment studies. Administration methods have included subcutaneous injection of coformulations of rapid-acting insulin + rHuPH20 as well as continuous subcutaneous infusion of coformulations or use of pretreatment of newly inserted infusion sets with rHuPH20 followed by standard continuous subcutaneous insulin infusion therapy. These studies have demonstrated acceleration of insulin absorption and action along with improvement in postprandial glycemic excursions and reduction in hypoglycemia risks. Further, rHuPH20 reduces intrasubject variability of insulin absorption and action and provides greater consistency in absorption and action profiles over wear time of an infusion set. Further studies of rHuPH20 in the take-home treatment setting are underway.

Improved postprandial glycemic control in patients with type 2 diabetes from subcutaneous injection of insulin lispro with hyaluronidase.

BACKGROUND: Coinjection of hyaluronidase has been shown to accelerate insulin absorption in healthy volunteers and patients with type 1 diabetes mellitus. This study was undertaken to compare the postprandial glycemic response of patients with type 2 diabetes mellitus (T2DM) administered insulin lispro with and without recombinant human hyaluronidase (rHuPH20) and regular human insulin (RHI) with rHuPH20. METHODS: This double-blind three-way crossover study compared the insulin pharmacokinetics and glucodynamic response to a standardized liquid meal (80 g of carbohydrate) in 21 patients with T2DM who received subcutaneous injections of individually optimized doses of lispro±rHuPH20 and RHI+rHuPH20. The optimum dose (targeting postprandial glucose [PPG] of 70-140 mg/dL) of each preparation was selected by the investigator following a fixed-dose escalation procedure in three dose-finding meals. RESULTS: Co-injection of lispro+rHuPH20 accelerated pharmacokinetics relative to lispro alone (time to peak insulin concentration, 43 vs. 74 min; P=0.0045) with increased exposure in the first hour (184% of control; P<0.0001) and reduced exposure after 2 h (67% of control; P=0.0001). These accelerated pharmacokinetics improved both total hyperglycemic excursions (area under the curve for 0-4 h >140 mg/dL, 56% of control; P=0.048) and hypoglycemic excursions (area under the curve for 0-8 h <70 mg/dL, 34% of control; P=0.033), allowing over three times as many patients to reach the American Diabetes Association's target of peak PPG <180 mg/dL without requiring glucose treatment for hypoglycemia. The mean optimum dose of lispro was reduced 8% from 0.275 U/kg without rHuPH20 to 0.254 U/kg with rHuPH20 (P=0.04). RHI+rHuPH20 had responses and optimum doses comparable to insulin lispro alone. All insulin preparations were well tolerated. CONCLUSIONS: Lispro+rHuPH20 provided superior control of glycemic excursion compared with lispro alone, with lower insulin requirements and reduced hypoglycemic excursions.

Use of recombinant human hyaluronidase to accelerate rapid insulin analogue absorption: experience with subcutaneous injection and continuous infusion.

OBJECTIVE: To discuss clinical studies in which recombinant human hyaluronidase (rHuPH20) was used to increase insulin dispersion and accelerate its absorption. METHODS: We reviewed 10 pertinent clinical studies, 8 of which had data available. RESULTS: In 4 euglycemic clamp studies, coinjection of rHuPH20 consistently yielded acceleration of insulin absorption, providing twice the insulin exposure during the first hour, greater and earlier peak exposure, and half the exposure beyond 2 hours after injection. Insulin-action profiles were similarly accelerated, with a 15-minute faster onset of insulin action and a 45-minute shorter duration of action for each of the 3 commercial rapid-acting insulin analogues. Infusion aspart insulin formulated with rHuPH20 also accelerated insulin absorption and action over the infusion set life when delivered by insulin pump. Administration of rHuPH20 reduced the inconsistency of insulin absorption and action profiles attributable to 3 factors-lack of reproducibility after identical injections, differences across insulin dose ranges, and changes over infusion site life. The rHuPH20-facilitated ultrafast profile consistently reduced hyperglycemic excursions both in injections immediately preceding liquid test meals and in bolus infusions immediately before solid test meals. rHuPH20-facilitated insulin administration has been well tolerated, with safety and tolerability similar to those with the comparator insulin alone. CONCLUSION: rHuPH20 accelerates insulin-action profiles to an extent comparable to the difference between rapid-acting insulin analogue profiles and those of regular insulin. Studies are currently under way to characterize the effect on diabetes management end points (including hemoglobin A1c, blood glucose, and rates of hyperglycemia) of insulin analogues coformulated with rHuPH20 for treatment of both type 1 and type 2 diabetes.

Reduction in intrasubject variability in the pharmacokinetic response to insulin after subcutaneous co-administration with recombinant human hyaluronidase in healthy volunteers.

BACKGROUND: This study was designed to test the hypothesis that co-administration of recombinant human hyaluronidase (rHuPH20) with regular insulin or insulin lispro will reduce intrasubject variability in pharmacokinetic end points compared with lispro alone. METHODS: Healthy adult volunteers (18-55 years old) were enrolled in this phase 1, randomized, double-blind, crossover study. Subjects were administered two injections, each on a separate occasion, of three treatments during six euglycemic clamps. Treatments were 0.15 U/kg insulin lispro, 0.15 U/kg insulin lispro with 5 µg/mL rHuPH20, and 0.15 IU/kg regular insulin with 5 µg/mL rHuPH20. Insulin formulations were administered at a concentration of 40 U/mL. Serum immunoreactive insulin levels, blood glucose concentration, and glucose infusion rate determinations were made at baseline and for approximately 8 h after study drug administration. Intrasubject variability was assessed using a general linear mixed model with a fixed effect for treatment using a compound symmetric covariance matrix. RESULTS: Co-injection of rHuPH20 with lispro significantly reduced intrasubject root mean square differences in time to peak serum insulin, time to early 50% peak serum insulin (t(50%)), and time to late t(50%) levels compared with lispro alone. Also, the intrasubject coefficient of variation for percentage of total area under the plasma concentration-versus-time curve for early time intervals compared with lispro alone was reduced. Intrasubject variability for regular insulin with rHuPH20 for most pharmacokinetic parameters was similar to the variability of lispro alone, although variability in early exposure was significantly reduced. CONCLUSIONS: Co-administration of rHuPH20 with lispro significantly reduced the variability of insulin pharmacokinetics relative to insulin lispro alone.