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Treatment Patterns, PROs Varied Among Authorized, Independent Generics

April 16, 2021

Research findings presented at AMCP 2021 suggest that differences in patient-reported outcomes (PROs) between authorized generics (AG) and independent generics (IG) were small and varied by therapeutic area, and market factors may be key in shaping observable switching patterns.  

“[AGs], often produced and marketed by the innovator company, have shown similar clinical outcomes compared to [IGs], overall, but subtle differences have been observed at the individual drug level. Yet, outcomes from the patient's perspective remain unexplored,” explained the researchers of the study. 

In order to better understand patient profile, treatment patterns and PROs linked with AG and IG use within various therapeutic areas, the research team examined prescription claims and PRO data from the National Health and Wellness Survey (NHWS).  

“Inclusion criteria were: ≥18 years old, billable national drug code for AG or IG, NHWS completion from June 2015-July 2019, AG or IG on-hand at NHWS completion, continuous insurance eligibility in 12 months pre- and post-NHWS completion (treatment patterns only).”

Based on survey eligibility, the researchers reviewed data on 20,229 patients across six therapeutic areas, including attention deficit-hyperactivity disorder [ADHD], antidepressants, beta blockers [BBs], calcium channel blockers, statins, and thyroid. Of these patients, 17.2% were AG users. They found that across four therapeutic areas, AG users were younger and also differed in regional access and insurance type compared with IG users. Further, other patient profile differences did not show a clear pattern.  

“Most PROs did not differ when adjusted for potential confounders, but AG and IG users differed in presenteeism and overall work impairment (BBs), health care resource use (BBs), and indirect costs (thyroid) (all, P<0.05),” they explained. “Adjusted adherence rates were similar for AGs and IGs in all therapeutic areas; persistence rates differed in ADHD and statins (both, P<0.05).” 

The researchers also found that AG users were more likely to switch to IG over IG users switching to AG. However, IG users were likely to switch among IG manufacturers. Finally, the researchers said that there were no differences identified in co-pays.

“Market factors (eg, specific generics available to patients at their pharmacy) may play a key role in shaping observable switching patterns,” the research team concluded. “The potential impact of switching should be viewed in light of these observed differences by medication type.”

Julie Gould


Alderfer J, Alvir J, Cook J, et al. Understanding treatment patterns and patient-reported outcomes associated with the use of authorized and independent generics. Poster presented at: AMCP 2021, April 12-16, 2021; Virtual.

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