Fiasp® flaws: are faster insulins worth it?

While insulin affordability and access have been headlining and causing great stress for many, there’s another insulin discussion gaining traction in the diabetes community. Novo Nordisk’s Fiasp®, an ultra fast insulin, may be presenting issues, mostly for people who use insulin pumps. Problems include skin or tissue irritation (inflammation at the infusion or injection site), resistance, little to no efficacy resulting in hyperglycaemia, and pain at site. Fiasp® retails for $685.77 US for 5 flextouch pens (3ml) of 100 units/ml.

Many people have decided the faster action isn’t worth the trouble. Some have given up altogether, dropping the faster insulin to return to their regular fast-acting analogue. Does Fiasp® have flaws causing people who use insulin pump therapy to drop off?

What’s an extra-fast insulin?

Fiasp® (faster insulin) is approved for subcutaneous or IV injection use, although there is little data available regarding its clinical utility in insulin pumps. This is unlike well-known fast-acting insulin analogues Humalog® (lispro), NovoLog® (aspart) and Apidra® (glulisin) which have been used in pumps for decades. These analogues offer coverage of mealtime excursions, but need to be injected (bolus) 10-20 minutes before a meal. This can be a problem if people inject during a meal or even after, which leads to hyperglycemia.

Faster insulin has two extra excipients, L-arginine and niacinamide (Vitamine B3), two natural agents approved by the European Medicines Agency and the US Food and Drug Administration. These agents facilitate the rapid movement of insulin through the capillaries into the blood. Faster insulin aspart covers glucose excursions much better. This leads to improved glucose results.

What did the original insulin pump trial study find?

In a 2017 study, 37 adults ( ≥ 18) were randomized in a 2:1 ratio of faster aspart: insulin aspart for 6 weeks of treatment using insulin pump therapy. Participants were instructed to change their pump sites every 72 (±4) hours. If there was any suspicion of occlusion or blockage, leakage, unexplained hyperglycemia, infusion-site reaction, or other technical reason, participants were instructed to report and change their site.

Overall, there were 21 premature infusion-set changes reported by 11 (44%) subjects in the faster aspart group and four premature changes reported by two (16.7%) subjects in the insulin aspart group. In the faster aspart group, six changes were prompted by unexplained hyperglycemia: only one experienced a blood glucose >300 mg/dl.

That research determined over the 6 weeks of treatment “no microscopically confirmed infusion-set occlusions were observed for faster aspart or insulin aspart indicating similar compatibility” for insulin pump therapy. The authors concluded “faster aspart demonstrated a nonsignificant trend toward improved glycemic control with no new safety issues.”

What are people using/used faster insulin aspart saying?

Comments from the internet over the past 12 months include:

“I’ve reached the end of my tether with Fiasp® after nine months. [] Angry red pump sites and inability to lower blood glucose levels.”

“Consistent tissue irritation after 48 hours.”

“I wish that Novo Nordisk would put out a version of Fiasp® for pumping.”

“We love Fiasp®, but only use it for shots!”

“Wild BG fluctuations occur ~48 hours from reports of my patients.”

What do the experts say?

One review determined that Novo Nordisk would help patients by examining the “softer “clinical endpoints, such as early infusion set change rates and the incidence of unexplained hyperglycemia, even suggesting a warning for people. “On the plus side, the results of the study do not suggest any fundamental safety issues that might reduce enthusiasm for further study of Fiasp® in pumps,” the author added.

Dr Jason Baker, a diabetes specialist with a significant patient population with type 1 diabetes in New York City, said “Fiasp® is new on the market so our clinical experience with it is more limited. I have many patients who very much like it, because of its faster onset, but I also have patients who do not think it has any discernible difference in action from other bolus analogs. That said, I am a firm believer that we need to continue to strive to make our insulin options more physiologic in action profile, and for some patients Fiasp helps to do this.“

Any further significant studies?

Currently, the following studies are ongoing or yet to be started:

• Evaluation of Fiasp® (Fast Acting Insulin Aspart) in 670G Hybrid Closed-Loop Therapy: anticipated completion May 2019.
• Comparison of Day and Night Closed-loop With Faster-acting Insulin Aspart With Insulin Aspart (AP-MFT-01): not yet recruiting.
• Study on How Fiasp® Can Influence Blood Sugar Levels of type1 Diabetic Patients in Their Daily Lives, With the Help of the Freestyle Libre® Device: enrolling by invitation.

To date, no current studies are examining the unexplained need for site changing, unexplained hyperglycemia or the skin irritations. Novo Nordisk is currently seeking approval for use of Fiasp® as a new mealtime insulin for children and adolescents with type 1 diabetes.