Very rapidly-acting insulin

• insulin analogues - designed to provide a more physiological insulin profile around meals
• mealtime insulins
  • rapid-acting insulin analogues general features (1,2)
    • rapid onset of action of approximately 15 mins
    • duration of action about 2–5 hours
    • can be injected immediately before or just after meals e.g. lispro, aspart, glulisine
• quicker onset of action and shorter duration time than short-acting insulins such as human actrapid. Short - acting insulins have a tendency to form hexamers in the insulin vials and so have a relatively slow onset of action
• types:
  • insulin lispro (Humalog) - identical amino acid structure to human insulin apart from the inversion of lysine and proline residues at B28 and B29
    • peak action after about 1 hour; duration of action 2-5 hours (insulin lispro)
  • insulin aspart (NovoRapid) - identical structure to human insulin apart from the replacement of proline at B28 with aspartic acid
    • insulin aspart is licensed for the treatment of patients with diabetes - no studies of the drug have been performed in children aged under 6 years (1)
      • the summary of product characteristics (SPC) recommends that it is injected subcutaneously "generally" immediately before a meal, but also that it can be given soon after the meal, when necessary
        • also recommends that insulin aspart should "normally" be used in combination with an intermediate- or long-acting insulin given at least once a day.
        • has a faster onset (10-20 minutes) and shorter duration (3-5 hours) of action than does soluble human insulin, with a maximum effect at 1-3 hours after injection
• insulin analogues facilitate a much more flexible insulin regimen - can be injected immediately before meals, less postprandial hypoglycaemia, there can be a more sensitive adjustment to match food intake at a particular time
  • a systematic review (3) concluded that:
    • compared with the use of conventional human insulin, use of the analogues was associated with a small decrease in HbA1c levels in patients with type 1 diabetes (weighted mean difference [WMD] -0.12%, 95% CI -0.17% to -0.07%) but not type 2 diabetes (WMD -0.02%, 95% CI -0.1% to 0.07%)
    • use of an analogue did not reduce the overall frequency of hypoglycaemia compared with human insulin, either in patients with type 1 diabetes (WMD of episodes/patient/month -0.2, 95% CI -1.2 to 0.9 ) or those with type 2 diabetes (-0.2, 95% CI -0.5 to 0.1
      • severe hypoglycaemia however occurred less often with the analogues than with human insulin
        • considering first type 1 diabetes
          • the median incidence (number of episodes/100 person-years) with the analogues was 20.3 (range 0-247.3) and with human insulin 37.2 (range 0-544)
        • considering type 2 diabetes
          • the median incidence with the analogues was 0.6 (range 0-30.3) and with human insulin 2.8 (range 0-50.4)
    • the authors reviewers felt unable to carry out a meta-analysis on the data on nocturnal hypoglycaemia

Fast-acting insulin aspart (Fiasp) is the first insulin of its class and was approved by the FDA in September 2017

• more rapid absorption and action of aspart insulin is achieved by altering the excipients in the aqueous solution: L-arginine for stabilization of the insulin molecule in solution and niacinamide for more rapid absorption
  • results in a faster initial absorption of insulin compared to NovoRapid(R) (which only contains insulin aspart)

Lispro (Humalog (R)) is a commercially available, rapid-acting human insulin analog indicated to improve glycemic control in adults and children with diabetes mellitus

• ultra-rapid lispro (URLi) (Lyumjev (R)) developed insulin lispro formulation utilizing two key enabling excipients, treprostinil and citrate, with independent mechanisms to accelerate the absorption of insulin lispro

Reference:

1. Drug and Therapeutics Bulletin (2004); 42(10):77-80.
2. MeRec Bulletin 2007;17(4).
3. Siebenhofer A et al. Short acting insulin analogues versus regular human insulin in patients with diabetes mellitus (Cochrane Review). In: The Cochrane Library, Issue 3, 2004.
4. Nally LM, Sherr JL, Van Name MA, Patel AD, Tamborlane WV. Pharmacologic treatment options for type 1 diabetes: what's new?. Expert Rev Clin Pharmacol. 2019;12(5):471-479. doi:10.1080/17512433.2019.1597705