Once-Weekly Insulin Therapy in Canine Diabetes Mellitus: Practical Considerations for Clinical Use

Managing canine diabetes mellitus (DM) extends beyond achieving glycemic control, it also involves maintaining long-term owner compliance and ensuring consistent treatment delivery. Dogs with DM are insulin-dependent, and conventional management typically requires twice-daily subcutaneous insulin administration^1,2,3. For many owners, this schedule presents practical challenges, including concerns about administering injections, fear of hypoglycemia, and difficulty arranging care when they are unavailable^1,4. Reducing injection frequency, while maintaining effective glycemic control, may help address some of these challenges without compromising clinical outcomes. 

One emerging approach involves an ultra-long-acting recombinant insulin construct designed for once-weekly subcutaneous administration. Understanding how this formulation behaves clinically can help veterinarians evaluate its potential role in diabetes management. 

How Does the Ultra-Long-Acting Insulin Work? 

Unlike conventional insulin preparations that prolong activity by delaying absorption from the subcutaneous injection site through insulin hexamer formation, this recombinant insulin combines a synthetic insulin molecule with the canine fragment crystallizable (Fc) region of immunoglobulins⁵. 

After entering circulation, the Fc portion binds to the neonatal Fc receptor (FcRn), allowing intracellular recycling and protecting the insulin molecule from proteolytic degradation. This mechanism extends circulating half-life without relying on delayed absorption from the injection site¹. 

Because prolonged activity is achieved through intracellular recycling rather than depot formation, the formulation can be prepared at different concentrations while maintaining its pharmacologic characteristics, which may be particularly useful when treating smaller dogs^1,5,6. 

Clinical Response During Treatment 

Dogs transitioned from twice-daily intermediate-acting insulin to once-weekly administration maintained several clinically important treatment goals throughout the treatment period. 

These included: 

• Stable body weight 

• Continued control of diabetic clinical signs 

• Maintenance of serum fructosamine concentrations 

• Comparable mean interstitial glucose concentrations relative to previous insulin therapy 

Glucose variability also remained comparable to baseline treatment, with no meaningful changes in glucose variability percentage (GVP), coefficient of variation, or standard deviation during treatment.12 

From a practical perspective, these findings suggest that extending dosing intervals does not necessarily require sacrificing day-to-day glycemic stability when patients are appropriately monitored. 

Monitoring Remains Essential 

Although injections were administered weekly, patient monitoring remained an important component of successful dose adjustment. 

Continuous interstitial glucose monitoring allowed evaluation of weekly glucose patterns rather than isolated measurements, supporting individualized dose modifications over time^1,7. Weekly assessments also incorporated: 

• Clinical signs reported by owners 

• Body weight 

• Interstitial glucose trends 

• Serum fructosamine concentrations 

• Routine hematologic and biochemical evaluation 

Treatment adjustments were based on the overall clinical picture rather than glucose values alone, reflecting the principle that diabetic control is best assessed through the combination of clinical improvement and avoidance of hypoglycemia rather than achievement of a specific glucose target¹. 

Safety Considerations in Practice¹ 

Clinical hypoglycemia was not reported during treatment, although occasional low interstitial glucose readings occurred. The frequency of low glucose measurements remained similar to that observed during conventional twice-daily insulin therapy. 

One clinically relevant consideration was the development of anti-drug antibodies approximately six weeks after treatment initiation in one dog. This corresponded with declining serum drug concentrations, worsening glycemic control, and the need to resume conventional insulin therapy. No comparable antibody response occurred in the remaining dogs. 

No systemic adverse effects or local injection-site reactions were identified during routine physical examinations or laboratory monitoring, supporting continued clinical observation throughout treatment. 

Practical Clinical Insights 

For practicing veterinarians, once-weekly recombinant insulin represents a different therapeutic strategy rather than simply a longer-acting insulin formulation. Successful implementation depends on careful patient selection, gradual dose titration, and close glucose monitoring during the initial treatment period. Continued assessment of clinical signs, body weight, and glycemic trends remains essential, particularly while establishing an effective maintenance dose. Monitoring for diminished response over time may also help identify patients developing anti-drug antibodies that could influence long-term treatment success. 

As longer-acting insulin options continue to evolve, reduced injection frequency may offer an opportunity to simplify diabetes management while maintaining clinically acceptable glycemic control in appropriately selected canine patients. 

References 

1. Hulsebosch SE, Pires J, Bannasch MJ, Lancaster T, Delpero A, Ragupathy R, Murikipudi S, Zion T, Gilor C. Ultra-long-acting recombinant insulin for the treatment of diabetes mellitus in dogs. Journal of veterinary internal medicine. 2022 Jul;36(4):1211-9. https://academic.oup.com/jvim/article-pdf/36/4/1211/66665369/jvim16449.pdf 

2. Heeley AM, O’Neill DG, Davison LJ, Church DB, Corless EK, Brodbelt DC. Diabetes mellitus in dogs attending UK primary-care practices: frequency, risk factors and survival. Canine Medicine and Genetics. 2020 Jun 10;7(1):6. https://link.springer.com/content/pdf/10.1186/s40575-020-00087-7.pdf 

3. Gilor CS, Niessen SJ, Furrow E, DiBartola SP. What's in a name? Classification of diabetes mellitus in veterinary medicine and why it matters. Journal of veterinary internal medicine. 2016 Jul;30(4):927-40. https://academic.oup.com/jvim/article-pdf/30/4/927/66690479/jvim14357.pdf 

4. Niessen SJ, Hazuchova K, Powney SL, Guitian J, Niessen AP, Pion PD, Shaw JA, Church DB. The big pet diabetes survey: perceived frequency and triggers for euthanasia. Veterinary sciences. 2017 May 14;4(2):27. https://www.mdpi.com/2306-7381/4/2/27 

5. Hirsch IB, Juneja R, Beals JM, Antalis CJ, Wright Jr EE. The evolution of insulin and how it informs therapy and treatment choices. Endocrine reviews. 2020 Oct 1;41(5):733-55. https://academic.oup.com/edrv/article-pdf/41/5/733/41724111/bnaa015.pdf 

6. Pyzik M, Sand KM, Hubbard JJ, Andersen JT, Sandlie I, Blumberg RS. The neonatal Fc receptor (FcRn): a misnomer?. Frontiers in immunology. 2019 Jul 10;10:1540. https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.01540/pdf 

7. Peyser TA, Balo AK, Buckingham BA, Hirsch IB, Garcia A. Glycemic variability percentage: a novel method for assessing glycemic variability from continuous glucose monitor data. Diabetes technology & therapeutics. 2018 Jan;20(1):6-16. https://journals.sagepub.com/doi/pdf/10.1089/dia.2017.0187