Effects of Shifting From Twice Daily Insulin Glargine or Detemir to Once Daily Insulin Degludec in Type 1 Diabetes
Condition: Type 1 Diabetes Mellitus
MeSH terms: Diabetes Mellitus, Type 1
Study type: Observational

Summary: 
      Rationale. Degludec is a longer-acting insulin analog compared to glargine and detemir. In a
      fraction of type 1 diabetic patients, insulin glargine and insulin detemir may not achieve
      24h coverage, reflected by raising pre-dinner glucose levels when they are administered at
      bedtime. As up-titration of bedtime long acting insulin increases risk of nocturnal
      hypoglycaemia, this clinical problem can be addressed by an additional injection of in the
      morning. These type 1 diabetic patients may benefit from shifting from twice daily insulin
      glargine/detemir to once daily insulin degludec, which shows an extended activity over 24h,
      up to 48h.

      Objective. To evaluate the effects of shifting from twice daily insulin glargine or detemir
      to once daily insulin degludec on HbA1c and glucose profiles in type 1 diabetic patients
      during a period of 3 months.

      Study design. Observational analytic prospective study. Protocol. Type 1 diabetic patients on
      twice daily insulin glargine or detemir (because of pre-dinner hyperglycemia due to supposed
      glargine/detemir coverage <24h) will be identified and enrolled. During a run-in period of 1
      week, the investigators will collect data on HbA1c values as IFCC/DCCT-aligned and on glucose
      profiles using glucose meters. Patients will undergo a 7-14 day continuous glucose monitoring
      before and eventually during (additional 7-14 days) the shift from twice to once daily basal
      insulin. Patients will be re-assessed 12 weeks after initiation of insulin degludec with
      determination of HbA1c and 7-14 day continuous glucose monitoring.
    

Detailed description: 
      Scientific background In type 1 diabetes mellitus, insulin therapy is a pivotal requirement,
      in order to achieve and maintain a satisfactory glycaemic control, as well as for the
      survival of the patient. Attaining a good glycaemic profile also allows limiting the impact
      of acute and chronic complications. Indeed, it is demonstrated that the maintenance of HbA1c
      levels as close as possible to 7% (53 mmol/mol), or even lower, can help in preventing or
      delaying the development of chronic complications. According to International Diabetes
      Federation (IDF) statements, the HbA1c target for young people with type 1 diabetes should be
      6.5% in order to ensure a longer life free from complications. Pursuing this HbA1c goal
      should possibly be achieved without excess incidence of hypoglycaemia, which can compromise a
      patient's autonomic reactivity and represents a barrier to good glycaemic control. For this
      reason, patterns of insulin therapy in type 1 diabetes are intended to reproduce as close as
      possible the physiological endogenous insulin secretion, both in tonic (baseline) and phasic
      (prandial) states. This objective is typically achieved through the basal-bolus scheme, by
      subcutaneous administration of rapid-acting insulin analogue at the 3 main meals, and 1 or
      more injections of long-acting insulin that supplies inter-prandial and nocturnal
      insulinization.

      Ideally the long-acting insulin should ensure a duration of 24 hours and be administered once
      a day. Long acting insulin analogues glargine and detemir are being used in type 1 diabetes.
      Clinical experience suggests that in a certain percentage of patients with type 1 diabetes,
      when administered at bedtime (h22.00), both glargine and detemir have a duration of less than
      24 hours, which is manifested by an increase in blood glucose during the late afternoon
      (h17.00-20.00) resulting in pre-dinner hyperglycaemia, a phenomenon that plays regularly on
      different days or may be inconsistent owing to day-by-day variations in absorption. This
      issue in the clinical management of type 1 diabetes, also known as "sunset phenomenon", does
      not have a unique solution and still represents an "unmet clinical need". Possible approaches
      to address the sunset phenomenon include: (1) the control of capillary BG at h16.00-17:00
      with eventual administration of an extra shots of rapid-acting insulin to correct the
      tendency to hyperglycaemia; (2) the use of a second long-acting insulin injection (usually at
      breakfast or lunch) in addition to that of the evening; (3) the replacement of the ultra-fast
      insulin at lunch with a pre-mixed insulin containing a mix of rapid-acting and
      protamine-bound intermediate-acting insulin; and (4) the transition to insulin pump therapy
      (CSII).

      However, all these approaches have limitations: (1) patients may not be able to control daily
      capillary BG in the afternoon, and are anyhow still subject to an additional injection; (2)
      the two doses of long-acting insulin can overlap, exposing the patient to an increased risk
      of hypoglycaemia at other times during the day, being the patient nevertheless subject to an
      additional injection; (3) using pre-mixed insulin, the variations of the ultra-fast insulin
      dose according to pre-lunch BG and carbohydrate intake also involves proportional changes in
      intermediate insulin fraction, entailing the risk of hyper- or hypoglycaemia; and (4) insulin
      pump therapy is costly, requires long therapeutic education and special efforts by the
      patient, and is not suitable for all patients with type 1 diabetes. The choice of one of
      these approaches is carried out at the discretion of physicians, in order to be
      individualized for specific patient's needs. It is therefore reasonable that the search for
      other strategies to address the sunset phenomenon should be pursued, in a way which could be
      more effective, safe and convenient for patients.

      In our Centre, one common solution to the sunset phenomenon issue for patients not eligible
      for the insulin pump therapy is a twice-daily administration of long-acting insulin analogue
      glargine or detemir. Indeed, the use premixed insulin does not fit well with the flexibility
      required for the therapy of type 1 diabetes, whilst an extemporaneous bolus administration is
      often inconstant, making identification of this phenotype of patients more difficult. The use
      of twice-daily administration of long-acting insulin is currently estimated in 20-25% of
      patients, while the use of premixed only represents 5-10%.

      Insulin Degludec is a new generation ultra-long acting insulin analogue which has been
      developed by Novo Nordisk A/S and recently marketed with the trade name of Tresiba®. It has
      been approved by the Regulatory European Agency (EMA) for subcutaneous use in patients with
      diabetes mellitus and is currently available in some European countries, including Italy,
      England, Germany, and Switzerland (EMA/689592/2012; EMEA/H/C/002498).

      Molecular modifications in insulin degludec monomer include the addition of a hexadecanoyl
      chain of fatty-diacid to Lysine-29 in B-chain (B29), and the deletion of Threonine at B30.

      Degludec is a basal insulin that forms soluble multi-hexamers upon subcutaneous injection,
      resulting in a depot from which insulin degludec is continuously and slowly absorbed into the
      circulation leading to a flat and stable glucose-lowering-effect of degludec (see figure 1).
      During a period of 24 hours with once-daily treatment, the glucose-lowering effect of
      degludec, in contrast to insulin glargine, was evenly distributed between the first and
      second 12 hours. Thus, the duration of action of degludec is beyond 42 hours within the
      therapeutic dose range.

      In phase 3 clinical trials involving patients with type 1 diabetes, insulin degludec showed
      similar glycaemic control in terms of HbA1c, but with a significant reduction in
      hypoglycaemia rates, especially at night, compared to glargine. This can also be explained by
      the lower day-to-day within-subject variability rate of insulin degludec respect to glargine.
      Given the longer duration of action of degludec, the timing of administration can be more
      flexible than glargine and detemir. As a result, it has been reported that the quality of
      life in patients with type 1 diabetes can significantly improve with insulin degludec use.

      The continuous glucose monitoring system (CGMS) allows a nonstop BG level monitoring over 24
      hours for up to 7 days. This tool can help patients to better understand how their food
      intake, physical activity and medications affect blood sugar levels, often giving them the
      possibility to better manage diabetes. Many CGMS devices have alarms that indicate when BG
      levels are going to be above or below a predetermined level. Devices are also equipped with a
      small glucose sensor inserted subcutaneously in the abdomen, which detects interstitial
      glucose levels every 5 minutes and sends a wireless signal to a terminal that can be easily
      applied to the belt or held in the pocket. When used in blind mode, CGMS recordings are only
      accessible to the diabetologist, but not to the patient, thereby allowing doctors to early
      detect problems in glycaemic trends (both hypo- or hyperglycaemic) 7 days of patient's normal
      daily life. It has been demonstrated that CGMS is capable of detecting hyper- or
      hypoglycaemic trends normally unidentifiable by the traditional SMBG provided by a
      glucometer. These systems are thus a valuable scientific and clinical support to define in
      greater detail 24-h glycaemic profiles, and represent the gold-standard for the evaluation of
      basal insulin efficacy and safety.

      Scientific Purpose The present study aims to evaluate whether switching from an insulin
      regimen with twice-daily administration of long-acting insulin glargine / detemir (in
      combination with ultra-fast acting insulin analogue at main meals) to insulin degludec
      administration once-a-day can improve 24-h glucose profiles (from CGM) and glycaemic control
      (HbA1c and FBG) in patients with type 1 diabetes mellitus which are in suboptimal glycaemic
      control (baseline HbA1c >6.5%). Since the present research protocol was inspired by a
      clinical problem without a conclusive solution (unmet clinical need), that is the sunset
      phenomenon, it was not considered appropriate to provide a control group by randomization to
      insulin degludec vs. continuation of the previous insulin regimen. This protocol represents
      therefore an observational prospective study. A pseudo-control group will be created by
      including those patients who are not willing to shift from twice daily glargine/detemir to
      once daily degludec, and by the same patients of the "degludec group" observed in the 3
      months before changing therapy.

      Plausibility and clinical relevance Results of phase 3 clinical trials investigating insulin
      degludec in patients suffering from type 1 diabetes mellitus have shown that a treatment
      regimen characterized by the use of once-daily insulin degludec vs. once-daily glargine, in
      association with the same rapid-acting inulin analogue at meals, results in a similar
      glycaemic control in HbA1c, with significantly lower frequency of hypoglycaemia in degludec
      arms. Patients with the sunset phenomenon, taken as representative sample of our Centre, show
      HbA1c average levels of approximately 8-8.5% despite therapy with twice daily administration
      of glargine or detemir. Therefore, it can be expected that the transition to a regimen with
      once-daily ultra-long acting insulin degludec could improve glycaemic control, as well as
      24-h profiles, without increase in hypo rates. This question is of particular clinical
      relevance, because will be addressed in the context of everyday clinical practice and not in
      a randomized-controlled trial. To date, there is scarcity of CGMS derived data on the
      efficacy of insulin Degludec. Therefore, the present study has the potential to better
      clarify the benefits of this new basal insulin.
    

Intervention name(s): Insulin degludec
Intervention type(s): Drug
Intervention description(s): Once daily injection of insulin degludec
Other intervention name(s): Tresiba
Intervention MeSH terms: Insulin
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Type 1 diabetic patients