Once-weekly insulin vs. daily injection: Study finds one is more effective than the other

Healthcare professionals holding a syringe of insulin treatment for type 2 diabetesShare on Pinterest
Could a once-weekly insulin injection be on the horizon as a treatment for type 2 diabetes? Catherine Falls Commercial/Getty Images
  • Researchers compared the efficacy of once-weekly and once-daily insulin treatments for type 2 diabetes.
  • They found that the once-weekly treatment icodec was more effective in lowering blood sugar levels than the standard once-daily injections.
  • Experts say further studies are needed to confirm the results.

A new, once-weekly insulin treatment could be a game changer for people with type 2 diabetes, according to a new study.

Researchers conducted a Phase 3 trial among people with type 2 diabetes, comparing the efficacy and safety of a once-weekly insulin called “icodec” with the standard once-daily injection degludec. Degludec is a long-acting insulin drug that helps regulate blood sugar levels.

They found that once-weekly icodec treatment resulted in greater reductions in blood sugar levels than once-daily degludec after 26 weeks.

The study was published in JAMA.

A previous study also found that icodec may produce similar glucose-lowering effects as daily insulin injections.

Over 37 million people in the United States have diabetes. Between 90-95% of these people have type 2 diabetes.

Insulin is a hormone made by the pancreas that allows cells to use glucose as energy. Type 2 diabetes occurs when cells no longer respond properly to insulin, which leads to increased blood sugar levels.

Over time, high blood sugar can damage several organs, including the eyes, kidneys, and heart. Treatment is thus necessary either by lifestyle modifications or non-insulin glucose-lowering agents.

Current guidelines recommend insulin-based drugs to lower blood sugar levels in people with type 2 diabetes when non-insulin medications are ineffective.

Currently, insulin-based drugs for type 2 diabetes require daily injections. Daily injections, however, can be cumbersome for patients, leading to poor adherence rates.

Research suggests that weekly injections improve adherence. One study found that patients taking once-weekly insulin treatments adhere to treatment regimens for an average of 333 days, compared to 269 days for those receiving daily injections.

Lack of adherence to insulin therapy can have severe consequences. Research indicates that poor adherence to insulin therapy in patients with diabetes is linked to a higher risk of death and hospitalization.

Increasing adherence rates is thus key to improving health outcomes and quality of life among people with diabetes.

For the study, the researchers recruited 588 individuals with an average age of 58 years old from 11 countries, including the USA, Argentina, and China.

All participants were being treated with non-insulin glucose-lowering agents, and just over a third were women.

During the study, they were randomly assigned to receive one of the following treatment regimens for 26 weeks:

  • Once-weekly icodec
  • One-weekly placebo
  • Once-daily degludec
  • Once-daily placebo

Ultimately, the researchers found that icodec reduced hemoglobin A1c (HBA1c) levels more than degludec.

HBA1c is a measure of average blood sugar levels over the preceding three months. People without diabetes tend to have HBA1c values of less than 5.7%; however, those with diabetes are recommended to maintain levels of 6.5% or below.

After 26 weeks, HBA1c levels among participants in the icodec group decreased from an average of 8.6% to 7%. Meanwhile, HBA1c levels in the degludec group fell from an average of 8.5% to 7.2%.

The researchers noted that fasting blood glucose and body weight did not significantly differ between participants taking icodec and degludec.

Medical News Today asked Dr. Absalon Gutierrez, associate professor of endocrinology with McGovern Medical School at UTHealth Houston, not involved in the study, what may explain icodec’s superior effects on lowering HBA1c values.

“Though we don’t know for sure, it likely has to do with patient adherence to the medication. Based on the way the study was designed, it was much easier to miss the degludec injections than it was to miss the icodec injections. This is likely the case in real life as well.”

– Dr. Gutierrez

The researchers also noted that from the start of the study until week 31, 8.9% of participants in the icodec group and 5.8% of those taking degludec experienced hypoglycemia– when blood sugar levels are lower than the standard range.

Furthermore, over the course of the trial, 177 (60.4%) patients in the icodec group and 167 (56.8%) of those receiving degludec experienced adverse events. The researchers wrote that 60 events in the icodec group and 46 in the degludec group were possibly linked to insulin treatments.

They noted, however, that most of the events were mild and included COVID-19, influenza, and diabetic retiniopathy- an eye condition that can cause vision loss in patients with diabetes.

While 5.1% of patients in the icodec group compared to 2% of those on degludec developed diabetic retinopathy, they noted that the absolute numerical difference was small, and that the observed differences had not been recorded in previous icodec trials.

The researchers wrote that their study had several limitations. They noted that the 26-week duration of the study means that longer-term effects remain unknown.

They further cautioned that they did not collect continuous glucose monitoring data or data on patient-reported outcomes.

Dr. Gutierrez noted: “Though icodec performed slightly superior in lowering HBA1c, it also showed more hypoglycemia. This would be expected, since it can’t be titrated as frequently. Also, based on the study design, the degludec titrations were not optimal.”

MNT also spoke with Dr. Lushun Wang, the Senior Consultant Orthopaedic Surgeon and Medical Director of Arete Orthopaedic Clinic in Singapore, not involved in the study:

“The duration of the studies can be further lengthened to ensure reliable long-term efficacy and safety. Rigorous and more in-depth testing should be done to better understand Icodec.

Data on continuous glucose monitoring may ensure a more robust insight into the control of blood glucose as well as its impact on the patient’s quality of life. Other than that, the trial was designed with a larger quantity of injections of Icodec compared to the daily regimen, which does not accurately reflect real-world use and any potential benefits in terms of treatment adherence.”

The researchers noted that icodec might improve treatment adherence and convenience among patients with type 2 diabetes by reducing injections from at least 365 to 52 per year.

They added that the small added glycemic benefit and convenience of once-weekly administration should outweigh the “small absolute risk of hypoglycemia.”

Dr. Wang noted: “Conveniently designed, Icodec can allow daily injections to be replaced by this once-weekly option. Its primary advantage is hedged on its ability to provide a stable and continuous release of insulin over the course of a week, helping to reduce fluctuations in blood glucose levels. This ability of Icodec can lead to the better overall control of blood glucose, as demonstrated in the superior HbA1c reduction observed in the trials.”

Dr. Guitierrez agreed that icodec insulin may be a good option for people who have difficulty adhering to once-daily basal insulin. He noted, however, that further studies are needed to better understand the hypoglycemia risk of taking icodec relative to once-daily insulin injections.

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