By Myles Starr

Glucagon-like peptide-1 agonists have exploded in use and popularity to treat obesity in nondiabetic patients since the approval of semaglutide injection (Wegovy, Novo Nordisk) in 2021. Although more than 90% of patients adhered to GLP-1 agonists through the end of clinical trials, new data suggest that real-world adherence rates are much lower. 

In an analysis of more than 4,000 adults, fewer than 1 in 3 participants took their medication persistently or adhered to their medication routine, researchers reported at AMCP 2024, in New Orleans.

“[Our] real-world persistency findings are substantially lower than those reported in clinical trials, from which cost offset modeling is frequently developed,” said Scott Leslie, PhD, MPH, the director of health outcomes for Prime Therapeutics/Magellan Rx Management (Prime/MRx), who presented these results in a bronze award–winning poster (E43). “The majority of individuals newly initiating GLP-1 obesity treatment did not complete a year of therapy, which raises treatment effectiveness concerns, particularly with the substantial investment in treatment.”

Dr. Leslie and his colleagues examined Prime Therapeutics claims data from 4,066 adults initiating GLP-1 therapy between Jan. 1 and Dec. 31, 2021. Only 32.3% of trial participants took their medication persistently, and only 27.2% adhered to their medication routine. Persistence was defined as avoiding a 60-day gap in therapy, and adherence was defined as having a proportion of days covered (PDC) greater than or equal to 80%.

The three most common GLP-1 drugs in the study were liraglutide (Saxenda, Novo Nordisk), a daily injection (39.4% of participants); semaglutide (Ozempic, Novo Nordisk), a weekly drug injection (34.4%); and semaglutide (Wegovy, Novo Nordisk), a weekly injection (10.3%). Persistency rates for these medications were, respectively, 19%, 47% and 36%. 

The median time to discontinuation ranged from 279 days in the semaglutide cohort to 120 days in the liraglutide cohort. The mean PDC was lower in the liraglutide cohort (40.8%) than in the semaglutide group (63.1%).

The low adherence and persistence rates may be related to many factors, Dr. Leslie said, including:

• the dosing schedule (daily vs. weekly injection);
• differences in side effects and weight loss among GLP-1 agonists;
• patients’ lack of perceived benefit;
• member cost share; and 
• drug shortages.

However, he sees opportunities to increase adherence and persistency. “Primary care providers and pharmacists can help patients understand that gastrointestinal side effects can be dose-related, which can have an impact when the dose may need to be gradually increased,” Dr. Leslie said. “We also recommend that providers and pharmacists work with their patients to manage GLP-1 product shortages and potential cost-share issues, including optimizing patient assistance programs.”

One major limitation of the study is that it only included data from commercially insured patients, and the insights gained are not generalizable to Medicare or Medicaid populations. Furthermore, participants who switched to compounded GLP-1 therapy or paid out of pocket for their GLP-1 product—details that were not reflected in insurance claims data—may have reduced the observed persistence and adherence rates.

Prime/MRx will continue to monitor trends in real-world GLP-1 data beyond the span of the original study.

Dr. Leslie reported no relevant financial disclosures beyond his stated employment.