Pulmonary function over 2 years in diabetic patients treated with prandial inhaled Technosphere Insulin or usual antidiabetes treatment: a randomized trial

Insulin Therapy for the Management of Diabetes Mellitus: A Narrative Review of Innovative Treatment Strategies

The discovery of insulin was presented to the international medical community on May 3, 1922. Since then, insulin has become one of the most effective pharmacological agents used to treat type 1 and type 2 diabetes mellitus. However, the initiation and intensification of insulin therapy is often delayed in people living with type 2 diabetes due to numerous challenges associated with daily subcutaneous administration. Reducing the frequency of injections, using insulin pens instead of syringes and vials, simplifying treatment regimens, or administering insulin through alternative routes may help improve adherence to and persistence with insulin therapy among people living with diabetes. As the world commemorates the centennial of the commercialization of insulin, the aims of this article are to provide an overview of insulin therapy and to summarize clinically significant findings from phase 3 clinical trials evaluating less frequent dosing of insulin and the non-injectable administration of insulin.

Novel formulations and drug delivery systems to administer biological solids

Recent advances in formulation sciences have expanded the previously limited design space for biological modalities, including peptide, protein, and vaccine products. At the same time, the discovery and application of new modalities, such as cellular therapies and gene therapies, have presented formidable challenges to formulation scientists. We explore these challenges and highlight the opportunities to overcome them through the development of novel formulations and drug delivery systems as biological solids. We review the current progress in both industry and academic laboratories, and we provide expert perspectives in those settings. Formulation scientists have made a tremendous effort to accommodate the needs of these novel delivery routes. These include stability-preserving formulations and dehydration processes as well as dosing regimes and dosage forms that improve patient compliance.

Long-Term Nonclinical Pulmonary Safety Assessment of Afrezza, a Novel Insulin Inhalation Powder

Afrezza delivers inhaled insulin using the Gen2 inhaler for the treatment of patients with type 1 and type 2 Diabetes. Afrezza was evaluated in long-term nonclinical pulmonary safety studies in 2 toxicology species. Chronic inhalation toxicology studies in rat (26 weeks) and dog (39 weeks) and an inhalation carcinogenicity study in rats were conducted with Technosphere insulin (Afrezza) and with Technosphere alone as a vehicle control. Respiratory tract tissues were evaluated by histopathology and cells expressing proliferating cell nuclear antigen (PCNA) were quantified in lungs of rats. Microscopic findings in rats exposed to Afrezza were attributed to the Technosphere particle component, were confined to nasal epithelia, and consisted of eosinophilic globules and nasal epithelial degeneration. There were no Afrezza-related changes in pulmonary PCNA labeling indices in alveoli, large bronchioles, or terminal bronchioles. Microscopic findings in rats exposed to Technosphere particles included eosinophilic globules, mucus cell hyperplasia, and epithelial degeneration in the nasal cavities. PCNA labeling indices were increased in large bronchioles and terminal bronchioles but not in alveoli. There were no Technosphere particle-related findings in the dog study. Afrezza did not exhibit carcinogenic potential in the 2-year study in rats. These nonclinical inhalation studies support the use of Afrezza in humans over extended periods.

A Review: The Prospect of Inhaled Insulin Therapy via Vibrating Mesh Technology to Treat Diabetes

Background: Inhaled insulin has proven to be viable and, in some aspects, a more effective alternative to subcutaneous insulin. Past and present insulin inhaler devices have not found clinical or commercial success. Insulin inhalers create a dry powder or soft mist insulin aerosol, which does not provide the required uniform particle size or aerosol volume for deep lung deposition. Methods: The primary focus of this review is to investigate the potential treatment of diabetes with a wet insulin aerosol. Vibrating mesh nebulisers allow the passive inhalation of a fine wet mist aerosol for the administration of drugs to the pulmonary system in higher volumes than other small-volume nebulisers. Results: At present, there is a significant focus on vibrating mesh nebulisers from the pharmaceutical and biomedical industries for the systemic administration of pharmaceuticals for non-traditional applications such as vaccines or the treatment of diabetes. Systemic drug administration using vibrating mesh nebulisers leads to faster-acting pharmaceuticals with a reduction in drug latency. Conclusions: Systemic conditions such as diabetes, require the innovative development of custom vibrating mesh devices to provide the desired flow rates and droplet size for effective inhaled insulin administration.

Effect of Subcutaneous Insulin on Spirometric Maneuvers in Patients with Type 1 Diabetes: A Case-Control Study

In order to compare spirometric maneuvers in adults according to the presence of type 1 diabetes, a case-control study including 75 patients with type 1 diabetes and 75 controls matched by sex, age, and body mass index were designed. In addition, 75 patients with type 1 diabetes were added to examine the potential the impact of subcutaneous insulin therapy on pulmonary function. Lung function measurements were assessed according to the global initiative for chronic obstructive lung disease guidelines. Basal insulin included long-acting insulin analogues and the delivered background insulin in patients with pump therapy. Bolus insulin included rapid-acting insulin analogues and the delivered insulin to cover postprandial hyperglycemias. Patients with type 1 diabetes showed lower spirometric values in comparison to the control group, together with a higher prevalence of forced expiratory volume in the first second (FEV1) <80% (10.7% vs. 2.7%, p = 0.044) and restrictive ventilatory pattern (10.7% vs. 0%, p = 0.006) The dose of basal insulin (U/kg/day) showed a negative correlation with forced vital capacity (FVC) (r = −0.205, p = 0.012) and FEV1 (r = −0.182, p = 0.026). The optimal cut-off value for identifying patients with a restrictive spirometric pattern was 0.5 U/kg/day of basal insulin. Additionally, basal insulin (U/kg/day) independently predicted the presence of both a restrictive spirometric pattern (OR = 77.1 (3.2 to 1816.6), p = 0.007) and an abnormal FEV1 (OR = 29.9 (1.5 to 562.8), p = 0.023). In patients with type 1 diabetes, higher basal insulin dosage seems to be related with an impairment of pulmonary function.

Diagnosis and Significance of Pulmonary Microvascular Disease in Diabetes

OBJECTIVE

To determine whether pulmonary microvascular disease is detectable in subjects with diabetes and associated with diminished exercise capacity using a novel echocardiographic marker quantifying the pulmonary transit of agitated contrast bubbles (PTAC).

RESEARCH DESIGN AND METHODS

Sixty participants (40 with diabetes and 20 control subjects) performed cardiopulmonary (maximal oxygen consumption [VO₂peak]) and semisupine bicycle echocardiography exercise tests within a 1-week period. Pulmonary microvascular disease was assessed using PTAC (the number of bubbles traversing the pulmonary circulation to reach the left ventricle, categorized as low PTAC or high PTAC). Echocardiographic measures of cardiac output, pulmonary artery pressures, and biventricular function were obtained during exercise.

RESULTS

Subjects with diabetes and control subjects were of similar age (44 ± 13 vs. 43 ± 13 years, P = 0.87) and sex composition (70% vs. 65% male, P = 0.7). At peak exercise, low PTAC was present in more participants with diabetes than control subjects (41% vs. 12.5%, χ²P = 0.041) and, in particular, in more subjects with diabetes with microvascular complications compared with both those without complications and control subjects (55% vs. 26% vs. 13%, χ²P = 0.02). When compared with high PTAC, low PTAC was associated with a 24% lower VO₂peak (P = 0.006), reduced right ventricular function (P = 0.015), and greater pulmonary artery pressures during exercise (P = 0.02).

CONCLUSIONS

PTAC is reduced in diabetes, particularly in the presence of microvascular pathology in other vascular beds, suggesting that it may be a meaningful indicator of pulmonary microvascular disease with important consequences for cardiovascular function and exercise capacity.

Rethinking the Viability and Utility of Inhaled Insulin in Clinical Practice

Despite considerable advances in pharmacotherapy and self-monitoring technologies in the last decades, a large percentage of adults with diabetes remain unsuccessful in achieving optimal glucose due to suboptimal medication adherence. Contributors to suboptimal adherence to insulin treatment include pain, inconvenience, and regimen complexity; however, a key driver is hypoglycemia. Improvements in the PK/PD characteristics of today's SC insulins provide more physiologic coverage of basal and prandial insulin requirements than regular human insulin; however, they do not achieve the rapid on/rapid off characteristics of endogenously secreted insulin seen in healthy, nondiabetic individuals. Pulmonary administration of prandial insulin represents an attractive option that overcomes limitations of SC insulin by providing more a rapid onset of action and a faster return of action to baseline levels than SC administration of rapid-acting insulin analogs. This article reviews the unique PK/PD properties of a novel inhaled formulation that support its use in patient populations with T1D or T2D.

Pharmacokinetic and Pharmacodynamic Properties of a Novel Inhaled Insulin

Advances in insulin treatment options over recent decades have markedly improved the management of diabetes. Despite this, glycemic control remains suboptimal in many people with diabetes. Although postprandial glucose control has been improved with the development of subcutaneously injected rapid-acting insulin analogs, currently available insulins are not able to fully mimic the physiological time-action profile of endogenously secreted insulin after a meal. The delayed onset of metabolic action and prolonged period of effect induce the risk of postprandial hyperglycemia and late postprandial hypoglycemia. A number of alternative routes of insulin administration have been investigated over time in an attempt to overcome the limitations associated with subcutaneous administration and to provide an improved time-action insulin profile more closely simulating physiological prandial insulin release. Among these, pulmonary insulin delivery has shown the most promise. Technosphere® Inhaled Insulin (TI) is a rapid-acting inhaled human insulin recently approved by the FDA for prandial insulin therapy. In this article we discuss the pharmacokinetic and pharmacodynamic properties of TI, and, based on key studies performed during its clinical development, the implications for improved postprandial glucose control.

Place of technosphere inhaled insulin in treatment of diabetes

Technosphere insulin (TI), Afrezza, is a powder form of short-acting regular insulin taken by oral inhalation with meals. Action of TI peaks after approximately 40-60 min and lasts for 2-3 h. TI is slightly less effective than subcutaneous insulin aspart, with mean hemoglobin A1c (HbA1c) reduction of 0.21% and 0.4%, respectively. When compared with technosphere inhaled placebo, the decrease in HbA1c levels was 0.8% and 0.4% with TI and placebo, respectively. Compared with insulin aspart, TI is associated with lower risk of late post-prandial hypoglycemia and weight gain. Apart from hypoglycemia, cough is the most common adverse effect of TI reported by 24%-33% of patients vs 2% with insulin aspart. TI is contraindicated in patients with asthma and chronic obstructive pulmonary disease. While TI is an attractive option of prandial insulin, its use is limited by frequent occurrence of cough, need for periodic monitoring of pulmonary function, and lack of long-term safety data. Candidates for use of TI are patients having frequent hypoglycemia while using short-acting subcutaneous insulin, particularly late post-prandial hypoglycemia, patients with needle phobia, and those who cannot tolerate subcutaneous insulin due to skin reactions.

Making Insulin Accessible: Does Inhaled Insulin Fill an Unmet Need?

Glycemic control is fundamental to the management of diabetes. However, studies suggest that a significant proportion of people with diabetes, particularly those using insulin, are not achieving glycemic targets. The reasons for this are likely to be multifactorial. The real and perceived risk of hypoglycemia and the need for multiple daily injections are widely recognized as key barriers to effective insulin therapy. Therefore, there is a clear unmet need for a treatment option which can help mitigate these barriers. Alternative methods of insulin administration have been under investigation for several years, and pulmonary delivery has shown the most promise to date. Inhaled Technosphere(®) Insulin (TI; Afrezza(®); MannKind Corporation) was approved in 2014 for use as prandial insulin in people with diabetes. TI shows a more rapid onset of action and a significantly faster decline in activity than current subcutaneous rapid-acting insulin analogs (RAAs), and TI is more synchronized to the physiologic timing of the postprandial glucose excursion. This results in lower postprandial hypoglycemia with similar glycemic control compared with RAAs, and less weight gain. Together with the ease of use of the TI inhaler and the reduction in the number of daily injections, these findings imply that TI may be useful in helping to overcome patient resistance to insulin, improve adherence and mitigate clinical inertia in health-care providers, with potential beneficial effects on glycemic control.

FUNDING

Writing and editorial support in the preparation of this publication was funded by Sanofi US, Inc., Bridgewater, New Jersey, USA. Funding for the article processing charges for this publication was provided by MannKind Corporation.

AFREZZA® (insulin human) Inhalation Powder: A Review in Diabetes Mellitus

Afrezza® (insulin human) inhalation powder is a rapid-acting Technosphere® insulin (TI) administered via a breath-powered oral inhaler to patients with diabetes requiring prandial insulin. TI, a dry powdered formulation of recombinant human insulin adsorbed onto a proprietary carrier, is designed to deliver insulin to the deep lung, at the level of the alveoli, where it is absorbed into the systemic circulation. In a randomized, open-label, multinational, phase III trial (trial 171) in type 1 diabetes (T1DM) patients, prandial TI via the Gen2 inhaler provided noninferior glycated haemoglobin (HbA1c) lowering compared with prandial subcutaneous insulin aspart. Although TI was associated with less HbA1c lowering, it provided significantly lower fasting plasma glucose levels and significantly less hypoglycaemia and bodyweight gain compared with insulin aspart. In a randomized, double-blind, placebo-controlled, multinational, phase III trial (trial 175) in type 2 diabetes (T2DM) patients, prandial TI via the Gen2 inhaler provided superior HbA1c lowering compared with inhaled placebo. Cough was the most commonly occurring non-hypoglycaemia adverse event across both studies. In a pooled analysis of tolerability data from phase II and III studies, the most commonly occurring non-hypoglycaemia adverse events in T1DM and T2DM patients were cough and throat pain/irritation. However, cough was generally mild, dry and decreased over time. In addition, treatment with TI was associated with positive patient-reported outcomes. Insulin human inhalation powder is an effective and generally well-tolerated agent for the prandial treatment of hyperglycaemia in T1DM and T2DM patients and may provide a solution to insulin initiation barriers such as injection phobia, concerns of bodyweight gain and concerns of hypoglycaemia.

A second-generation inhaled insulin for diabetes mellitus

PURPOSE

The pharmacologic properties of a recently approved inhaled insulin product, its unique delivery system, and the results of clinical safety and efficacy trials are reviewed.

SUMMARY

Afrezza (also called Technosphere Insulin, MannKind Corporation, Valencia, CA) is a novel ultrarapid-acting insulin formulation indicated for use in improving glycemic control in selected patients with type 1 or type 2 diabetes mellitus. Afrezza is not intended as a substitute for traditional basal therapy with injectable long-acting insulin but may be used to provide prandial insulin coverage; it must be used in combination with long-acting insulin in patients with type 1 diabetes. Administered before meals using a dry-powder inhalation device, Afrezza is formulated with a novel excipient (fumaryl diketopiperazine) that dissolves instantly in lung fluid and releases recombinant human insulin for absorption. In clinical trials, rates of hypoglycemia in Afrezza-treated patients were significantly lower than rates reported in comparator groups receiving injectable insulin products. The most commonly reported adverse effect of Afrezza is coughing, which tends to occur shortly after inhalation and is typically mild. Afrezza is not recommended for use in patients who smoke (or have recently stopped smoking) and those with a chronic lung disease such as asthma or chronic obstructive pulmonary disease. Afrezza is not recommended for the treatment of diabetic ketoacidosis.

CONCLUSION

Afrezza is a safe and effective treatment for selected adults with type 1 or type 2 diabetes, potentially providing an alternative to injectable insulin for prandial blood glucose control.

Inhaled technosphere insulin: a novel delivery system and formulation for the treatment of types 1 and 2 diabetes mellitus

Complications from uncontrolled diabetes mellitus were reduced significantly with the introduction of insulin more than 90 years ago. Despite the proven benefits of normal glycemic levels, patients are deterred by the inconvenience and perceived pain related to multiple daily subcutaneous insulin injections. Inhaled insulin was first approved by the U.S. Food and Drug Administration (FDA) in 2006, but because profit margins did not achieve expectations, the drug manufacturer discontinued sales 2 years later. The second-generation inhaled insulin, developed with Technosphere technology, received FDA approval in 2014. The pharmacology, pharmacokinetics, drug interactions, clinical safety and efficacy, patient satisfaction, dosage and administration, warnings, precautions, contraindications, adverse effects, and place in therapy of inhaled Technosphere insulin are reviewed in this article.

Impact of symptomatic upper respiratory tract infections on insulin absorption and action of Technosphere inhaled insulin

OBJECTIVE

Uncomplicated, acute upper respiratory tract infections (URTIs) occur in patients with diabetes at a similar frequency to the general population. This study (NCT00642681) investigated the effect of URTIs on the pharmacokinetic (PK) and pharmacodynamic (PD) properties of Technosphere inhaled insulin (TI) in patients with type 1 or type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a phase 2 study conducted in patients who developed a URTI while being treated with TI in a phase 3 study (N=20, mean age 50 years, 60% men). Patients underwent two 4-hour meal challenges, during which blood samples were drawn to measure serum fumaryl diketopiperazine (FDKP; the excipient representing an essential part of TI), serum insulin, serum C-peptide, and plasma glucose. The primary outcome was the ratio of serum FDKP area under the concentration-time curve from 0 to 240 min (AUC0-240 min) during URTI and after clinical resolution of URTI symptoms (≥15 to ≤45 days).

RESULTS

No significant differences in PK parameters were seen during URTI versus post-URTI for FDKP. The ratio of serum FDKP AUC0-240 min during URTI and post-URTI was 1.1 (SD 0.6), p=0.4462. Plasma glucose concentrations during each 4-hour meal challenge were similar, showing small non-significant differences. No adverse events, including hypoglycemia, occurred during meal challenge visits.

CONCLUSIONS

Development of an active, symptomatic URTI during treatment with TI had no significant impact on the PK/PD properties of TI, suggesting that no adjustment in prandial insulin dosing is needed. However, if patients are unable to conduct proper inhalation, they should administer their prandial insulin subcutaneously.

TRIAL REGISTRATION NUMBER

NCT00642681; Results.

Technosphere insulin: inhaled prandial insulin

INTRODUCTION

Insulin therapy is a mainstay for treatment of diabetes mellitus; however, many barriers to insulin exist. Insulin human inhalation powder (technosphere insulin) is a new FDA-approved alternative to subcutaneous bolus insulin.

AREAS COVERED

This is an overview of technosphere insulin (TI). Pharmacokinetics, clinical efficacy, safety and tolerability are discussed.

EXPERT OPINION

TI is more quickly absorbed than subcutaneous insulin therapies and has a shorter duration of action. It appears to be noninferior compared with subcutaneous insulin regimens, and is associated with less hypoglycemia. Thus, it may serve as an alternative insulin agent in patients reluctant to administer multiple subcutaneous injections of insulin daily or in patients who experience late postprandial hypoglycemia with subcutaneous insulin. Cough is the most common side effect, but tends to be mild and transient. A small decrease in the forced expiratory volume has been demonstrated, but does not appear to progress and is reversible. Patients should have periodic pulmonary function tests. TI is contraindicated in patients with chronic lung disease. The long-term risk of lung cancer is being monitored but at this point does not appear to be higher than the expected incidence of lung cancer in this population.

Inhaled Technosphere Insulin Versus Inhaled Technosphere Placebo in Insulin-Naïve Subjects With Type 2 Diabetes Inadequately Controlled on Oral Antidiabetes Agents

OBJECTIVE

To investigate the efficacy and safety of prandial Technosphere inhaled insulin (TI), an inhaled insulin with a distinct time action profile, in insulin-naïve type 2 diabetes (T2D) inadequately controlled on oral antidiabetes agents (OADs).

RESEARCH DESIGN AND METHODS

Subjects with T2D with HbA1c levels ≥7.5% (58.5 mmol/mol) and ≤10.0% (86.0 mmol/mol) on metformin alone or two or more OADs were randomized to add-on prandial TI (n = 177) or prandial Technosphere inhaled placebo (TP) (n = 176) to their OAD regimen in this double-blind, placebo-controlled trial. Primary end point was change in HbA1c at 24 weeks.

RESULTS

TI significantly reduced HbA1c by -0.8% (-9.0 mmol/mol) from a baseline of 8.3% (66.8 mmol/mol) compared with TP -0.4% (-4.6 mmol/mol) (treatment difference -0.4% [95% CI -0.57, -0.23]; P < 0.0001). More TI-treated subjects achieved an HbA1c ≤7.0% (53.0 mmol/mol) (38% vs. 19%; P = 0.0005). Mean fasting plasma glucose was similarly reduced in both groups. Postprandial hyperglycemia, based on 7-point glucose profiles, was effectively controlled by TI. Mean weight change was 0.5 kg for TI and -1.1 kg for the TP group (P < 0.0001). Mild, transient dry cough was the most common adverse event, occurring similarly in both groups (TI, 23.7%; TP, 19.9%) and led to discontinuation in only 1.1% of TI-treated and 3.4% of TP-treated subjects. There was a small decline in forced expiratory volume in 1 s in both groups, with a slightly larger decline in the group receiving TI (TI, -0.13 L; TP, -0.04 L). The difference resolved after treatment discontinuation.

CONCLUSIONS

Prandial TI added to one or more OADs in inadequately controlled T2D is an effective treatment option. Mild, transient dry cough was the most common adverse event.

Efficacy, safety, and patient acceptability of Technosphere inhaled insulin for people with diabetes: a systematic review and meta-analysis

BACKGROUND

Technosphere inhaled insulin is a non-invasive alternative to subcutaneous injectable insulin for adults with type 1 or 2 diabetes. In this systematic review and meta-analysis of randomised controlled trials, we aimed to establish the efficacy, safety, and patient acceptability of Technosphere inhaled insulin in patients with diabetes.

METHODS

We searched MEDLINE, the Cochrane Central Register of Controlled Clinical Trials, ClinicalTrials.gov, and relevant US regulatory documents for reports of randomised trials published in English up to May 30, 2015, that compared mealtime Technosphere inhaled insulin with placebo, subcutaneous insulin, or oral antidiabetic drugs in people with type 1 or type 2 diabetes. Two reviewers independently extracted data for outcomes of interest and risk of bias. Endpoints included changes in HbA1c concentration and bodyweight, and safety outcomes, including severe hypoglycaemia and pulmonary toxicity. When three or more studies provided relevant data, we did a meta-analysis for the outcome using a profile-likelihood random-effects model.

FINDINGS

13 trials met the inclusion criteria for qualitative systematic review; 12 met the inclusion criteria for quantitative meta-analysis (n=5273; age range 18-80). HbA1c decrease from baseline was greater with subcutaneous insulin than with Technosphere inhaled insulin (net difference 0·16%, 95% CI 0·06-0·25; eight trials). However, inhaled insulin was associated with less weight gain (net difference -1·1 kg, -2·1 to -1·6; three trials) and a smaller risk of severe hypoglycaemia (odds ratio 0·61, 95% CI 0·35-0·92; five trials). Incidence of mild transient cough was increased in people allocated to inhaled insulin (odds ratio 7·82, 6·14-10·15; seven trials) compared with those allocated to active comparator groups, as was the decrease in forced expiratory volume in 1 s (net difference -0·038 L, -0·049 to -0·026; five trials). Quality of life and overall patient satisfaction did not differ significantly between inhaled insulin groups and active comparator groups (no numerical estimate).

INTERPRETATION

Glycaemic efficacy of Technosphere inhaled insulin is lower than that of subcutaneous insulin, but inhaled insulin has a lower risk of severe hypoglycaemia and weight gain. Long-term outcomes and safety with Technosphere insulin should be further investigated. Until further data for safety become available, Technosphere inhaled insulin should be reserved for healthy adults with diabetes who do not have pulmonary disease and who would otherwise delay initiating or intensifying insulin therapy because they are unwilling or unable to use injectable insulin.

FUNDING

None.

Future prospect of insulin inhalation for diabetic patients: The case of Afrezza versus Exubera

The current review was designed to compare between the insulin inhalation systems Exubera and Afrezza and to investigate the reasons why Exubera was unsuccessful, when Afrezza maker is expecting their product to be felicitous. In January 2006, Pfizer secured FDA and EC approval for the first of its kind, regular insulin through Exubera inhaler device for the management of types 1 and 2 diabetes mellitus (DM) in adults. The product was no longer available to the market after less than two years from its approval triggering a setback for competitive new inhalable insulins that were already in various clinical development phases. In contrary, MannKind Corporation started developing its ultra-rapid-acting insulin Afrezza in a bold bid, probably by managing the issues in which Exubera was not successful. Afrezza has been marketed since February, 2015 by Sanofi after getting FDA approval in June 2014. The results from this systematic review indicate the effectiveness of insulin inhalation products, particularly for patients initiating insulin therapy. Pharmaceutical companies should capitalize on the information available from insulin inhalation to produce competitive products that are able to match the bioavailability of subcutaneous (SC) insulin injection and to deal with the single insulin unit increments and basal insulin requirements in some diabetic patients or extending the horizon to inhalable drug products with completely different drug entities for other indications.

Insulin administration: present strategies and future directions for a noninvasive (possibly more physiological) delivery

Insulin is a life-saving medication for people with type 1 diabetes, but traditional insulin replacement therapy is based on multiple daily subcutaneous injections or continuous subcutaneous pump-regulated infusion. Nonphysiologic delivery of subcutaneous insulin implies a rapid and sustained increase in systemic insulin levels due to the loss of concentration gradient between portal and systemic circulations. In fact, the liver degrades about half of the endogenous insulin secreted by the pancreas into the venous portal system. The reverse insulin distribution has short- and long-term effects on glucose metabolism. Thus, researchers have explored less-invasive administration routes based on innovative pharmaceutical formulations, which preserve hormone stability and ensure the therapeutic effectiveness. This review examines some of the recent proposals from clinical and material chemistry point of view, giving particular attention to patients' (and diabetologists') ideal requirements that organic chemistry could meet.

Onset of diabetes modulates the airway smooth muscle reactivity of guinea pigs: role of epithelial mediators

BACKGROUND

Diabetes induces lung dysfunction, leading to alteration in the pulmonary functions. Our aim was to investigate whether the early stage of diabetes alters the epithelium-dependent bronchial responses and whether nitric oxide (NO), KATP channels and cyclooxygenase (COX) pathways contribute in this effect.

METHODS

Guinea pigs were treated with a single injection of streptozotocin (180 mg/kg, i.p.) for induction of diabetes. Airway conductivity was assessed by inhaled histamine, using a non-invasive body plethysmography. The contractile responses of tracheal rings induced by acetylcholine (ACh) and relaxant responses of precontracted rings, induced by isoproterenol (IP) were compared in the presence and absence of the epithelium. Effects of N(ω)-Nitro-L-arginine methyl ester (L-NAME, a nitric oxide synthase inhibitor), glybenclamide (a KATP channel inhibitor) and indomethacin (a COX inhibitor) were also assessed in diabetic guinea pigs.

RESULTS

Early stage diabetes did not alter the airway conductivity. ACh-induced bronchoconstriction in epithelium intact tracheal rings was not affected by the onset of diabetes, however a reduction in the increased ACh responses due to epithelium removal, to L-NAME or to indomethacin was observed. The relaxation response to IP was impaired in trachea from guinea pigs in which diabetes had just developed. Early diabetes significantly reduced the IP response to glybenclamide and to indomethacin.

CONCLUSION

Our results demonstrate that the early stage of diabetes, modulate the bronchial reactivity to both ACh and IP by disrupting the NO, KATP channels and COX pathways, without affecting the airway conductivity in guinea pigs.

New developments in insulin therapy for type 2 diabetes

Insulin has classically been considered a treatment of last resort for individuals with type 2 diabetes, delayed until all other efforts by the patient and healthcare provider have failed. Recent treatment guidelines recommend the use of insulin, in particular basal insulin, as part of a treatment regimen earlier in the disease process. Many patients are reticent about initiating insulin, so therapies that allow insulin treatment to be more tailored to individual needs are likely to result in greater acceptance and patient adherence with therapy. To meet this need, a range of insulin products are in development that aim to increase absorption rate or prolong the duration of action, reduce peak variability and weight gain associated with insulin treatment, and offer alternative delivery methods. This review describes insulin products in clinical development, new combination therapies, and new devices for insulin delivery.

Inhaled insulin: a breath of fresh air? A review of inhaled insulin

PURPOSE

Despite many advances in diabetes care over the last century, some elements of insulin therapy remain inadequate for optimal care of the patient with diabetes. There is a need for improved pharmacokinetics and pharmacodynamics of rapid-acting insulin analogues to mimic physiologic insulin secretion. In addition, a major barrier to successful insulin therapy has been patient resistance. Alternative routes of insulin administration, including inhaled insulin, have been under investigation for several years. This review discusses the rationale for pulmonary delivery of insulin, compares previous inhaled insulin products, reviews the literature on the safety and efficacy of a current inhaled insulin formulation under investigation, and compares this product with other prandial insulin products.

METHODS

English-language studies and reviews of inhaled insulin were searched in MEDLINE, the ClinicalTrials.gov registry (through May 2014), and the US Food and Drug Administration Website.

FINDINGS

Inhaled insulin has several favorable characteristics due to pulmonary anatomy/physiology and the lack of injections. Pharmacokinetic and pharmacodynamic studies have shown a time-action profile suitable for prandial insulin use. Inhaled insulin seems to be safe and effective compared with other prandial insulin products and may be preferable to subcutaneous rapid-acting insulin analogues in terms of time-action profiles and rates of hypoglycemia. Small decreases in forced expiratory volume in 1 second (FEV1) have been shown with inhaled insulin, although this finding is not progressive over time and reverses with cessation of the medication.

IMPLICATIONS

Although several inhaled insulin products have been under investigation, only one (Exubera(®) [Nektar Therapeutics, San Carlos, California/Pfizer Inc, New York, New York]) was approved by the US Food and Drug Administration, and it was pulled from the market after only a short period of time. Technosphere(®) insulin (MannKind Corporation, Valencia, California) is currently the only inhaled insulin that remains under investigation. A review of the past and present literature on inhaled insulin is pertinent in understanding the current status of inhaled insulin and its risks and benefits. The current literature suggests that inhaled insulin could be a valuable option for prandial insulin administration, with a favorable risk to benefit ratio in some patients.

Bioavailability of therapeutic proteins by inhalation--worker safety aspects

A literature review and analysis of inhalation bioavailability data for large therapeutic proteins was conducted in order to develop a practical estimate of the inhalation bioavailability of these drugs. This value is incorporated into equations used to derive occupational exposure limits(OELs) to protect biopharmaceutical manufacturing workers from systemic effects. Descriptive statistics implies that a value of 0.05, or 5% is an accurate estimate for large therapeutic proteins (molecular weight ≥ 40kDa). This estimate is confirmed by pharmacokinetic modeling of data from a human daily repeat-dose inhalation study of immunoglobulin G. In conclusion, we recommend using 5% bioavailability by inhalation when developing OELs for large therapeutic proteins.

Methods to enhance delivery of prandial insulin and basal-prandial insulin

Most physicians are comfortable with initiating basal insulin replacement therapy in their patients with type 2 diabetes who are no longer meeting treatment goals with oral antidiabetic agents. What is more challenging is what to do when treatment goals are no longer being met despite adequate titration of basal insulin. Both fasting plasma glucose and postprandial glucose contribute to hemoglobin A1C levels. Addressing postprandial glucose levels can be accomplished by several approaches. Traditionally this has meant moving to basal bolus insulin, which is considered the gold standard. Premixed insulin may also be used. Data is also emerging for basal "plus" strategies, that is, incremental addition of prandial insulin injections. Newer approaches also reviewed in this article included premixed formulations containing ultra-long acting basal insulin with rapid-acting insulin analogs, inhaled insulin and insulin jet injectors, as well as the use of incretin-based therapies.

Insulin therapies: Current and future trends at dawn

Insulin is a key player in the control of hyperglycemia for type 1 diabetes patients and selective individuals in patients of type 2 diabetes. Insulin delivery systems that are currently available for the administration of insulin include insulin syringes, insulin infusion pumps, jet injectors and pens. The traditional and most predictable method for the administration of insulin is by subcutaneous injections. The major drawback of current forms of insulin therapy is their invasive nature. To decrease the suffering, the use of supersonic injectors, infusion pumps, sharp needles and pens has been adopted. Such invasive and intensive techniques have spurred the search for alternative, more acceptable methods for administering insulin. Several non-invasive approaches for insulin delivery are being pursued. The newer methods explored include the artificial pancreas with closed-loop system, transdermal insulin, and buccal, oral and pulmonary routes. This review focuses on the new concepts that are being explored for use in future.

Effect of cigarette smoke extract on insulin transport in alveolar epithelial cell line A549

BACKGROUND

The main purpose of this study was to evaluate the effect of cigarette smoke extract (CSE) on insulin transport in alveolar epithelial cells.

METHODS

We first examined the effect of CSE pretreatment on cell viability, mRNA expression, and lamellar body structures in A549 cells. Then the effect of CSE pretreatment on FITC-insulin transport was examined.

RESULTS

When A549 cells were treated with 30 μg/ml of CSE for 48 h, the expression of some mRNAs abundantly expressed in type II alveolar epithelial cells such as surfactant protein B was significantly increased. Lamellar bodylike structures became more evident with CSE treatment. FITC-insulin uptake from the apical side and subsequent efflux to the basal side was enhanced by CSE treatment in A549 cells. The enhancing effect of CSE on FITC-insulin uptake was concentration-dependent and reversible. A concentration-dependent enhancing effect of CSE on FITC-insulin uptake was also observed in normal, primary cultured alveolar type II epithelial cells isolated from rats.

CONCLUSIONS

Treatment of A549 cells by CSE may direct the cells to a more type II-like phenotype. In accordance with this observation, FITC-insulin uptake was enhanced by CSE treatment. These results may partly explain the higher insulin absorption from the lung in smokers than in nonsmokers.

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.

Novel non-invasive methods of insulin delivery

INTRODUCTION

Insulin has usually been administered subcutaneously in the treatment of diabetes mellitus. Alternative delivery routes of insulin are expected to overcome some limitations, mainly concerned with the possibility of hypoglycemia episodes, weight gain and inadequate post-meal glucose control, in order to lead a better patient compliance.

AREAS COVERED

This review article covers all the most relevant non-invasive insulin delivery methods under development, respective technology and clinical data available according to their status of development. Special focus is given to the systems with late clinical trial evidences, their achievements and pitfalls. Pulmonary and oral appear to be the most advantageous routes, with regard to the long list of potentially marketed products.

EXPERT OPINION

Alternative insulin delivery to the subcutaneous administration is more and more close to the success, being fundamental that any optimized technology could overcome the overall low mucosal bioavailability of insulin, mostly due to its early degradation before absorption, inactivation and digestion by proteolytic enzymes and poor permeability across mucosal epithelium because of its high molecular weight and lack of lipophilicity.

Coverage of prandial insulin requirements by means of an ultra-rapid-acting inhaled insulin

Barriers to the use of prandial insulin regimens include inadequate synchronization of insulin action to postprandial plasma glucose excursions as well as a significant risk of hypoglycemia and weight gain. Technosphere® insulin (TI) is an inhaled ultra-rapid-acting human insulin that is quickly absorbed in the alveoli. With a time to maximum plasma drug concentration of approximately 14 min and a time to maximum effect of 35 to 40 min, TI more closely matches the postprandial insulin concentrations seen in nondiabetic individuals. Studies have shown that long-term administration of prandial TI in combination with long-acting basal insulin results in reductions in hemoglobin A1c comparable to conventional subcutaneously injected prandial insulins but with improved control of early postprandial BG. Furthermore, TI has been associated with less weight gain and a lower incidence of hypoglycemia, which may enhance patient satisfaction and acceptability of insulin therapy. This review discusses the clinical properties of TI and proposes strategies for optimal use.