Canadian Province Successfully Switches Patients to Insulin Glargine Biosimilar

Switching patients from originator insulin glargine to a biosimilar was not associated with any negative effects on health services, according to an analysis of the impacts of a mandatory nonmedical switching policy in British Columbia, Canada. The findings were published in Clinical Therapeutics.

Multiple Canadian provinces have enacted policies mandating switches from costly originator products to less expensive biosimilars for patients covered by the provincial drug plans. Starting November 25, 2019, PharmaCare, the drug plan of British Columbia, Canada, only covered biosimilar insulin glargine with coverage of the originator only provided under special circumstances.

Researchers evaluated patients treated with the originator product and who were targeted by the mandatory switch by the province’s Biosimilars Initiative. Patients enrolled in a provincial plan between November 27, 2015, and May 27, 2019, were eligible, and they were followed up to May 25, 2020.

They created a prospective policy (intervention) cohort, which included patients (n = 15,344) with a prescription for the originator in the 6 months leading up to the mandatory switch on May 27, 2019, and 3 historical (control) cohorts with patients (n = 15,968 to 17,310) filling a prescription for the originator product in a 6-month identification period for 2016, 2017, and 2018. The median age of the cohorts ranged from 63.0 to 65.0 years, and 43.5% to 43.9% were female.

As anticipated, there was an increased use of biosimilar insulin glargine after the switch policy launched. In the 8 months prior to the launch, 9.1% of prescription refills for insulin glargine were for a biosimilar. However, by 6 months after the end of the transition period for the policy launch, the biosimilar accounted for 79.0% of refills. After the transition, biosimilar prescriptions accounted for 99.2% of the insulin glargine refills covered by PharmaCare.

At the end of the 1-year follow-up period, 78.5% of patients in the policy cohort had transitioned to the biosimilar, although 2.8% transitioned back to the originator after using the biosimilar.

“Most of the patients who did not transition to biosimilar insulin glargine continued to refill the originator insulin glargine and paid out of pocket or through plans and programs other than PharmaCare,” the authors noted.

The cumulative incidence of refills in the policy cohort was higher than anticipated and there was also a decrease in the cumulative incidence of discontinuation of insulin glargine as a result of the policy. There was a 3.3% increase in units of insulin glargine dispensed 290 days after the policy was implemented in the policy cohort.

The authors were unclear what caused the increased use of insulin glargine. The conjecture that patients who switched to the biosimilar needed higher doses to control their blood glucose levels seemed unlikely since previous studies have confirmed the biosimilar has similar efficacy to the originator. They suggested that given the timing, the third and fourth refillings might have been an impact of patients stockpiling medications during the start of the COVID-19 pandemic.

The researchers also found an increase in the use of oral antidiabetic medications, including an increase in the initiation of new oral antidiabetics 96 days after the policy was implemented. They surmised that the increase was unrelated to the biosimilar policy, and instead was associated with new recommendations that lead to the increased use of sodium-glucose cotransporter 2 inhibitors.

Compared with historical cohorts, there was “a signal of an increase in third visits” to physicians and nurse practitioners in the policy cohort. These third visits occurred between days 162 and 313. However, they found the policy had no impact on visits to the emergency department or discharges with a diagnosis of blood glucose imbalance. There was a small and transient increase in hospital discharges.

“The results of this analysis should encourage decision makers and health care managers to consider similar biosimilar policies as part of a broad approach to optimize treatments—leveraging the health care savings from such policies to increase access to improved treatment options,” the authors concluded.

Reference

Fisher A, Kim JD, Dormuth C. The impact of mandatory nonmedical switching from originator to biosimilar insulin Ggargine. Clin Ther. Published online June 9, 2022. doi:10.1016/j.clinthera.2022.05.003