Comparison of Outcomes Following a Switch From a Brand to an Authorized Versus Independent Generic Drug

Generic drugs use during the COVID-19 pandemic among Lebanese patients using psychotropics: An opportunity for generic drug promotion

Introduction

The Coronavirus disease of 2019 (COVID-19) pandemic has imposed several challenges leading to the shortage of medications due to the disruption of their supply chains. Among others, patients using psychotropics encountered difficulties finding their medication despite the efforts of investing in local production. Encouraging patients to use generic drugs can be an effective strategy to ensure sustainable access to medication.

Objectives

This study aimed to describe the consumption of psychotropic medications during the COVID-19 pandemic and the willingness together with the reasons for using generic drugs. It also assessed the association between generic drugs and the general characteristics of the patients.

Design

A cross-sectional study was performed over a period of 4 months (July-October 2021) targeting 128 patients using psychotropic drugs.

Results

The sample included more women than men with a mean age of 38 years. Antidepressants were the psychotropic medications mostly consumed followed by anti-anxiety medications. Almost 13% of the patients started using psychotropics either through self-prescription or a friend's advice and 73.4% used generic drugs. Fear of dependence, unavailability of the brand drug, and pharmacist's recommendation were the main reported reasons for using generic drugs.

Conclusion

During the COVID-19 pandemic, the consumption of psychotropics increased due to new prescriptions and self-medication. No differences were noted between using generics and the characteristics of the patients in contrast to previous studies which support the implementation of generic prescription and substitution policies.

Understanding treatment patterns and patient-reported outcomes associated with the use of authorized generics and corresponding independent generics across multiple therapeutic areas

OBJECTIVES

To assess patient characteristics, treatment patterns, and patient-reported outcomes (PROs) associated with authorized generics (AGs) and independent generics (IGs) use.

METHODS

Prescription claims and National Health and Wellness Survey (NHWS) data were linked. Adults with billable national drug code (AG or IG), NHWS completion from June 2015 to July 2019, AG or IG on-hand at NHWS completion, and continuous insurance eligibility in 12 months pre- and post-NHWS completion were included. To be included, all unique medication formulations had to have at least one AG and one IG observation. PRO index date was NHWS completion; claims index date was defined as the first prescription claim identified during the 180-day period prior to NHWS completion for the same active ingredient and formulation type that was on-hand at NHWS completion.

RESULTS

Patients (N = 20,229; 17.2% AG users) in six therapeutic areas (attention deficit-hyperactivity disorder [ADHD], antidepressants, beta blockers [BBs], calcium channel blockers [CCBs], statins, and thyroid) were included. Generally, AG (vs. IG) users were younger and differed in regional access and insurance type (all, p < .05). In multivariable analysis, significant differences were observed for presenteeism and overall work impairment (BBs), healthcare provider visits (BBs), and indirect costs (thyroid) (all, p < .05). AG and IG users differed in persistence (ADHD and statins; both, p < .05) and switch (BBs and CCBs; both, p < .01) rates.

CONCLUSIONS

PRO differences were often small in magnitude and varied by therapeutic area. The impact of switching should consider observed PRO differences, patient preferences, and market availability of AG and IG alternatives.

Evaluation of Switch-to-Brand Rates as a Potential Signal for Therapeutic Equivalency of Generic Antidepressants: A Real-World Retrospective Cohort Study

Negative clinical outcomes after switching from brand to generic antidepressants have raised concerns regarding therapeutic equivalency. This research aims to estimate the prevalence of switching and to identify predictors for generic to brand switching for various antidepressants. This retrospective cohort study utilized data from a 10% random sample of enrollees in the IQVIA PharMetrics Plus claims database from 2007-2015. The base cohort consisted of commercially insured patients who were prescribed escitalopram, duloxetine, or venlafaxine extended release (ER) anytime from the year prior to the generic launch through December 2014. The primary outcome was defined as a switch from generic to a brand within 14 days of sustained generic use in a 1-year follow-up period. Adjusted logistic regression and generalized estimating equations for repeated measures estimated the drug specific and overall odds of switch-to-brand among brand initiators relative to generic initiators, respectively. A total of 102,831 unique patients across 3 drug products contributed to the final analytic sample. The overall prevalence of switch from generic to brand was 0.74%. Across all three antidepressants, brands initiators were more likely to experience a switch-to-brand: escitalopram (odds ratio (OR): 14.41, 95% confidence interval (CI): 11.14-18.64), duloxetine (OR: 8.08, 95% CI: 4.85-13.41) and venlafaxine ER (OR: 16.46, 95% CI: 11.56-23.46). The pooled odds of a switch-to-brand in brand vs. generic initiators was 13.77 (95% CI: 11.35-16.71). This study suggests a low overall switch-to-brand prevalence and may support therapeutic equivalence between brand and generic antidepressants. Initiating with a brand product was the strongest predictor for switching back to brand and suggests that patient experience may play a role in drug utilization.

Understanding authorized generics-A review of the published clinical data

WHAT IS KNOWN AND OBJECTIVES

Despite the large body of evidence demonstrating equivalent efficacy and safety for branded drugs and their generic counterparts, some patients and providers have the perception that generics may be less safe and effective than branded agents. Authorized generics (AGs) are a category of generic drugs defined by the United States Food and Drug Administration (FDA) as being the same as the brand-name drug without the brand's name on the label and which may have minor differences, such as tablet or capsule markings for identification. Studies in which AGs are considered along with other generics may increase our understanding of factors that may influence perceptions about generics and shed light on areas where education may be impactful. The objectives of this paper are to provide information about AGs, review studies in which they have been evaluated and explore the role that AGs may fill in the individualized treatment of patients.

METHODS

A literature review was conducted on 30 September 2019 with follow-up search on 4 March 2020. The search was focussed on published papers and meeting abstracts that provided information on AGs with respect to medical and health outcomes of therapy as well as switching in individuals receiving branded, AG, or other generic agents. Information about patients' perceptions of generic medications and adherence to therapy was also included. Additional information, including relevant government sources, such as the FDA website and the Federal Trade Commission Report, was included as appropriate.

RESULTS

The literature specific to AGs is limited, but available data clearly highlight the importance of patient perception of generics as well as medication appearance as factors that may affect adherence and potentially more frequent switchbacks to branded agents from generics or AGs.

WHAT IS NEW AND CONCLUSION

To our knowledge, this is the first narrative review to provide a summary of the published evidence about AGs with respect to clinical and health outcomes and switching. There is a need for more research and education regarding the use of AGs in clinical practice if they are to become more recognized as a potential treatment choice for patients. Generic medications play an important role in the healthcare system, and AGs may be able to provide an option to meet the specific needs of individual patients.

Patient factors associated with oral generic olanzapine initiation and substitution among Medicaid beneficiaries: a new user cohort study

OBJECTIVE

Generic drugs typically are less expensive than branded products; however, several factors can limit generic drug utilization. This study assesses the associations of patient factors with generic olanzapine initiation and substitution.

METHODS

A retrospective new user cohort study was conducted using the 2011-2012 Medicaid administrative claims data. Beneficiaries continuously enrolled during the 6 month washout period prior to their initial oral brand or generic olanzapine prescription were included and followed up to 12 months. Among brand olanzapine new users, time to generic substitution and competing risk outcomes was estimated using the Fine-Gray cumulative incidence function. Patient demographic and health service utilization factors were assessed in the multivariate cause-specific hazards model.

RESULTS

Among olanzapine new users, 70.7% patients initiated generic treatment. Beneficiaries aged ≥21, and living in the Midwest and West regions were more likely to initiate generic olanzapine. Among brand new users, 28.2% switched to generic olanzapine, 23.6% switched to an alternative atypical antipsychotic treatment and 38.0% discontinued within 12 months. Beneficiaries who resided in urban areas (adjusted hazard ratio [AHR) = 0.53, 95% CI = 0.37-0.75) and had prior hospitalizations (AHR = 0.85, 95% CI = 0.75-0.96) had lower rates of generic substitution, whereas those with emergency department (ED) visits (AHR = 1.06, 95% CI = 1.02-1.10) had a higher rate of generic substitution. In addition, beneficiaries in different age subgroups also had different rates of generic substitution in different regions.

CONCLUSION

Medicaid beneficiaries' age, geographic region, prior hospitalization and ED utilization were associated with generic olanzapine initiation and substitution. Tailored educational outreach targeting these patient subgroups might improve generic olanzapine utilization.

Oral generic tacrolimus initiation and substitution in the Medicaid population: a new user cohort study

OBJECTIVE

Although existing studies have compared clinical efficacy and pharmacokinetics of generic with brand tacrolimus, little is known about generic tacrolimus utilization patterns or factors predicting generic substitution. This study examines associations between patient-level factors and generic tacrolimus initiation or substitution among new users of oral generic or brand-name tacrolimus.

METHODS

This new user retrospective cohort study identified 374 beneficiaries who initiated generic or brand tacrolimus treatment, using 100% Medicaid administrative claims data from 11 states in 2011-2012. Outcomes were generic tacrolimus initiation and substitution within 12 months of treatment initiation. Multivariable logistic regression and Cox proportional hazards models were used to identify factors associated with generic tacrolimus initiation and substitution.

RESULTS

Two-thirds of oral tacrolimus new users initiated generic tacrolimus. Patients who were older age and black were significantly more likely to initiate generic tacrolimus (adjusted odds ratio [AOR] = 1.02, 95% confidence interval [CI] = 1.001-1.03; AOR = 2.54, 95% CI = 1.40-4.62; respectively). Patients with more concomitant prescriptions, more comorbidities, or higher initial daily dosage had significantly lower likelihoods of initiating generic tacrolimus (AOR = 0.93, 95% CI = 0.87-0.99; AOR = 0.87, 95% CI = 0.77-0.99; AOR = 0.96, 95% CI = 0.93-0.993). Among brand tacrolimus new users, 23.6% substituted with generics within 12 months, and an addition of prior hospitalization or unit of initial daily dosage increment was associated with 35% (subdistribution hazard ratio [SHR] = 1.35, 95% CI = 1.02-1.76) or 2% (SHR = 1.02, 95% CI = 1.00-1.04) increase in likelihood of generic substitution, respectively.

CONCLUSIONS

Understanding associations between patient-level factors with generic tacrolimus initiation and substitution could help practitioners and policymakers monitor treatment effect and facilitate generic tacrolimus utilization.

Generic escitalopram initiation and substitution among Medicare beneficiaries: A new user cohort study

OBJECTIVES

To examine patterns of generic escitalopram initiation and substitution among Medicare beneficiaries.

METHODS

This retrospective new user cohort used a 5% random sample of 2013-2015 Medicare administrative claims data. Fee-for-service Medicare beneficiaries continuously enrolled in Parts A, B, and D during a 6-month washout period prior to their initial generic or brand oral escitalopram prescriptions were included (n = 12,351). The primary outcomes were generic escitalopram treatment initiation, and among brand escitalopram initiators, generic substitution within 12 months. Patient demographics, health service utilization, and prescription level factors were measured and assessed.

RESULTS

Among all escitalopram initiators, about 88.2% Medicare beneficiaries initiated generic escitalopram. Beneficiaries who were younger age, male, residing in non-Northeast regions or urban area, in the Part D plan deductible benefit phase, and filling prescriptions at community/retail pharmacies were more likely to initiate generic treatment. Among brand escitalopram initiators (n = 1,464), about 20.7% switched to generic escitalopram, 31.2% switched to another alternative antidepressant, 25.1% discontinued treatment, and 8.7% were lost to follow up or passed away within 12 months after brand initiation. Factors associated with generic escitalopram substitution included region (Midwest vs. Northeast, adjusted hazard ratio (HR) = 1.46, 95% CI = 1.04-2.05), pre-index hospitalization (HR = 1.31; 95% CI = 1.16-1.48) and lower escitalopram average daily dosage (HR = 0.97; 95% CI = 0.95-0.99).

CONCLUSIONS

In 2013-2015, almost 90% Medicare beneficiaries initiated generic escitalopram treatment. Among brand escitalopram initiators, about 1 in 5 patients switched to generic escitalopram within 1 year, as compared to 1 in 4 or 1 in 3 who discontinued current or switched to alternative treatment, respectively. Medicare beneficiary's geographic region was independently associated with generic escitalopram initiation and substitution. Findings from this study not only provide up-to-date evidence in generic escitalopram use patterns among Medicare population, but also can guide educational and practice interventions to further increase generic escitalopram use.

Impact of brand drug discount cards on private insurer, government and patient expenditures

BACKGROUND

Brand discount cards have become a popular way for patients to reduce out-of-pocket spending on drugs; however, controversy exists over their potential to increase insurers' costs. We estimated the impact of brand discount cards on Canadian drug expenditures.

METHODS

Using national claims-level pharmacy adjudication data, we performed a retrospective comparison of prescriptions filled using a brand discount card matched to equivalent generic prescriptions between September 2014 and September 2017. We investigated the impact on expenditures for 3 groups of prescriptions: those paid only through private insurance, those paid only through public insurance and those paid only out of pocket.

RESULTS

We studied 2.82 million prescriptions for 89 different medications for which brand discount cards were used. Use of discount cards resulted in 46% higher private insurance expenditures than comparable generic prescriptions (+$23.09 per prescription, 95% confidence interval [CI] $22.97 to $23.21). Public insurance expenditures were only slightly higher with cards: an increase of 1.3% or $0.37 per prescription (95% CI $0.33 to $0.41). Finally, out-of-pocket transactions using a card resulted in mean patient savings of 7% or $3.49 per prescription (95% CI -$3.55 to -$3.43). The impact varied widely among medicines across all 3 analyses.

INTERPRETATION

The use of brand discount cards increased costs to private insurers, had little impact on public insurers and resulted in mixed impacts for patients. These effects likely resulted from private insurers reimbursing brand drug prices even when generics were available and from discount cards being adjudicated after claims were sent to other insurers in most cases. Patients and their clinicians should recognize that discount cards have mixed impacts on out-of-pocket costs.

Drug price, dosage and safety: Real-world evidence of oral hypoglycemic agents

OBJECTIVES

Drug price reduction is one of the major policies to restrain pharmaceutical expenses worldwide. This study explores whether there is a relationship between drug price and clinical quality using real-world data.

METHODS

Patients with newly-diagnosed type 2 diabetes receiving metformin or sulfonylureas during 2001 and 2010 were identified using the claim database of the Taiwan universal health insurance system. Propensity score matching was performed to obtain comparable subjects for analysis. Pharmaceutical products were categorized as brand-name agents (BD), highpriced generics (HP) or low-priced generics (LP). Indicators of clinical quality were defined as the dosage of cumulative oral hypoglycemic agents (OHA), exposure to other pharmacological classes of OHA, hospitalization or urgent visit for hypoglycemia or hyperglycemia, insulin utilization and diagnosis of diabetic complications within 1 year after diagnosis.

RESULTS

A total of 40,152 study subjects were identified. A generalized linear mix model showed that HP and BD users received similar OHA dosages with comparable clinical outcomes. By contrast, LP users had similar outcomes to BD users but received a 39% greater OHA dosage. A marginally higher risk of poor glycemic control in LP users was also observed.

CONCLUSIONS

Drug price is related to indicators of clinical quality. Clinicians and health authorities should monitor the utilization, effectiveness and clinical safety indicators of generic drugs, especially those with remarkably low prices.

Healthy User Bias in Comparative Safety Studies for Brand-Name vs. Generic Products: The Example of Warfarin

Warfarin was selected as a case study to examine confounding when comparing a product across different manufacturers because it is a narrow therapeutic index drug with prevalent beliefs for brand-name superiority. Medicare beneficiaries aged ≥65 years with atrial fibrillation and an incident outpatient warfarin prescription from July 2006 through July 2015 were included in the study population (N = 746,098). Substantial imbalances were observed between brand-name warfarin and generics for (i) clinical comorbidity, (ii) socioeconomic status, (iii) prescriber specialty, (iv) recent ambulatory and emergent care, (v) drug adherence, (vi) pharmacy setting (e.g., retail, mail-order), and (vii) risk scores for bleeding and thrombosis. Patients receiving brand-name warfarin were healthier than patients receiving generic manufactured warfarin. Utilization of generic warfarin products also differed by geographic region and pharmacy setting. Manufacturer-level comparative-safety studies for causal inference should carefully consider the presence of these imbalances and their potential for introducing healthy user bias.

Evaluation of Switching Patterns in FDA's Sentinel System: A New Tool to Assess Generic Drugs

INTRODUCTION

Nearly 90% of drugs dispensed in the US are generic products.

OBJECTIVE

The aim of this study was to develop and implement a tool for analyzing manufacturer-level drug utilization and switching patterns within the US Food and Drug Administration's Sentinel system.

METHODS

A descriptive tool was designed to analyze data in the Sentinel common data model and was tested with two case studies-metoprolol extended release (ER) and lamotrigine ER-using claims data from four Sentinel data partners. We plotted initiators of each brand and generic product over time. For metoprolol ER, we evaluated rates of switching from generics around the time of manufacturing issues. For lamotrigine ER, we examined rates of switching back to the brand among those who switched from brand to generic.

RESULTS

We identified 1,651,285 initiators of metoprolol ER products between July 2008 and September 2015. We observed a large decrease in monthly metoprolol ER initiators (from 25,465 in December 2008 to 13,128 in February 2009), corresponding to recalls by generic manufacturers. We observed simultaneous increases in utilization of the authorized generic and brand products. We identified 4266 initiators of lamotrigine ER with an epilepsy diagnosis between January 2012 and September 2015. Among those who switched from brand to generic, the cumulative incidence of switching back was close to 20% at 2 years. Switchback rates were higher for the first available generic products.

CONCLUSIONS

This developed tool was able to elucidate novel utilization and switching patterns in two case studies. Such information can be used to support surveillance of generic drugs and biosimilars.

Comparative effectiveness of generic and brand-name medication use: A database study of US health insurance claims

BACKGROUND

To the extent that outcomes are mediated through negative perceptions of generics (the nocebo effect), observational studies comparing brand-name and generic drugs are susceptible to bias favoring the brand-name drugs. We used authorized generic (AG) products, which are identical in composition and appearance to brand-name products but are marketed as generics, as a control group to address this bias in an evaluation aiming to compare the effectiveness of generic versus brand medications.

METHODS AND FINDINGS

For commercial health insurance enrollees from the US, administrative claims data were derived from 2 databases: (1) Optum Clinformatics Data Mart (years: 2004-2013) and (2) Truven MarketScan (years: 2003-2015). For a total of 8 drug products, the following groups were compared using a cohort study design: (1) patients switching from brand-name products to AGs versus generics, and patients initiating treatment with AGs versus generics, where AG use proxied brand-name use, addressing negative perception bias, and (2) patients initiating generic versus brand-name products (bias-prone direct comparison) and patients initiating AG versus brand-name products (negative control). Using Cox proportional hazards regression after 1:1 propensity-score matching, we compared a composite cardiovascular endpoint (for amlodipine, amlodipine-benazepril, and quinapril), non-vertebral fracture (for alendronate and calcitonin), psychiatric hospitalization rate (for sertraline and escitalopram), and insulin initiation (for glipizide) between the groups. Inverse variance meta-analytic methods were used to pool adjusted hazard ratios (HRs) for each comparison between the 2 databases. Across 8 products, 2,264,774 matched pairs of patients were included in the comparisons of AGs versus generics. A majority (12 out of 16) of the clinical endpoint estimates showed similar outcomes between AGs and generics. Among the other 4 estimates that did have significantly different outcomes, 3 suggested improved outcomes with generics and 1 favored AGs (patients switching from amlodipine brand-name: HR [95% CI] 0.92 [0.88-0.97]). The comparison between generic and brand-name initiators involved 1,313,161 matched pairs, and no differences in outcomes were noted for alendronate, calcitonin, glipizide, or quinapril. We observed a lower risk of the composite cardiovascular endpoint with generics versus brand-name products for amlodipine and amlodipine-benazepril (HR [95% CI]: 0.91 [0.84-0.99] and 0.84 [0.76-0.94], respectively). For escitalopram and sertraline, we observed higher rates of psychiatric hospitalizations with generics (HR [95% CI]: 1.05 [1.01-1.10] and 1.07 [1.01-1.14], respectively). The negative control comparisons also indicated potentially higher rates of similar magnitude with AG compared to brand-name initiation for escitalopram and sertraline (HR [95% CI]: 1.06 [0.98-1.13] and 1.11 [1.05-1.18], respectively), suggesting that the differences observed between brand and generic users in these outcomes are likely explained by either residual confounding or generic perception bias. Limitations of this study include potential residual confounding due to the unavailability of certain clinical parameters in administrative claims data and the inability to evaluate surrogate outcomes, such as immediate changes in blood pressure, upon switching from brand products to generics.

CONCLUSIONS

In this study, we observed that use of generics was associated with comparable clinical outcomes to use of brand-name products. These results could help in promoting educational interventions aimed at increasing patient and provider confidence in the ability of generic medicines to manage chronic diseases.

Bioequivalence and Therapeutic Equivalence of Generic and Brand Bupropion in Adults With Major Depression: A Randomized Clinical Trial

Controversy persists about bupropion XL 300 mg generic equivalence to brand product. A prospective, randomized, double-blinded crossover in 70 adults with major depression in stable remission taking any bupropion XL 300 mg tested bioequivalence and therapeutic equivalence of available XL 300 mg products. After a 4-week lead-in on patients' existing bupropion, four 6-week phases evaluated brand and three generics. Patients were uninformed of switching. Drug overencapsulation ensured blinding. There were no differences between any generic and brand, or between generics, in peak plasma concentration (C_max ) and area under the plasma concentration-time curve over the 24-hour dosing interval (AUC_0-24 ) for racemic bupropion or major metabolites. All generics met formal bioequivalence criteria for bupropion and metabolites. There were no differences between generics and brand, or between generics, in depression symptoms or side effects, assessed by every 3-week in-person interview and daily smartphone-based self-report. There were no differences in patients' perceptions of bupropion products. Results show three bupropion XL 300 mg generic products are both bioequivalent and not therapeutically different from brand drug and each other.

Differences in rates of switchbacks after switching from branded to authorized generic and branded to generic drug products: cohort study

OBJECTIVES

To compare rates of switchbacks to branded drug products for patients switched from branded to authorized generic drug products, which have the same active ingredients, appearance, and excipients as the branded product, with patients switched from branded to generic drug products, which have the same active ingredients as the branded product but may differ in appearance and excipients.

DESIGN

Observational cohort study.

SETTING

Private (a large commercial health plan) and public (Medicaid) insurance programs in the US.

PARTICIPANTS

Beneficiaries of a large US commercial health insurer between 2004 and 2013 (primary cohort) and Medicaid beneficiaries between 2000 and 2010 (replication cohort).

MAIN OUTCOME MEASURES

Patients taking branded products for one of the study drugs (alendronate tablets, amlodipine tablets, amlodipine-benazepril capsules, calcitonin salmon nasal spray, escitalopram tablets, glipizide extended release tablets, quinapril tablets, and sertraline tablets) were identified when they switched to an authorized generic or a generic drug product after the date of market entry of generic drug products. These patients were followed for switchbacks to the branded drug product in the year after their switch to an authorized generic or a generic drug product. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals after adjusting for demographics, including age, sex, and calendar year. Inverse variance meta-analysis was used to pool adjusted hazard ratios across all drug products.

RESULTS

A total of 94 909 patients switched from branded to authorized generic drug products and 116 017 patients switched from branded to generic drug products and contributed to the switchback analysis. Unadjusted incidence rates of switchback varied across drug products, ranging from a low of 3.8 per 100 person years (for alendronate tablets) to a high of 17.8 per 100 person years (for amlodipine-benazepril capsules), with an overall rate of 8.2 per 100 person years across all drug products. Adjusted switchback rates were consistently lower for patients who switched from branded to authorized generic drug products compared with branded to generic drug products in the primary cohort (pooled hazard ratio 0.72, 95% confidence interval 0.64 to 0.81). Similar results (0.75, 0.62 to 0.91) were observed in the replication cohort.

CONCLUSION

Switching from branded to authorized generic drug products was associated with lower switchback rates compared with switching from branded to generic drug products.

Medication changes after switching from CONCERTA® brand methylphenidate HCl to a generic long-acting formulation: A retrospective database study

Background

Observational studies of switching from branded to generic formulations of the same drug substance often lack appropriate comparators for the subjects who switched. Three generic formulations were deemed equivalent to Concerta: an authorized generic (AG) identical except for external packaging, and two other generics (EG).

Objective

Compare the incidence of a combined endpoint (switching back to Concerta, changing the use of immediate release methylphenidate (MPH), stopping all long-acting methylphenidate, or starting a new medication) among people switched from Concerta to the AG versus the EG.

Methods

Cohort study from the Truven CCAE database of people aged 6 to 65 diagnosed with ADHD, treated with Concerta, and switched to the EG or to the AG formulation.

Results

In the EG arm 24.6% and in the AG arm 19.7% of subjects switched back to Concerta. The proportion of subjects meeting the combined endpoint was 39.5% in the EG arm, 32.9% in the AG arm, a crude risk ratio of 1.20 (95% CI 0.94, 1.54). After adjustment by propensity score stratification, the adjusted odds ratio (OR) was 1.23 (95% CI 0.90, 1.70). In an unplanned analysis using a different method of adjustment, the adjusted OR was 1.00 (95% CI 0.69, 1.44).

Discussion

This study did not detect a difference between the proportion of people who met the study endpoint in the two study arms, i.e. between those who switched to a generic formulation that was identical to Concerta except for external packaging and those who switched to the comparison generics. The high incidence of the combined endpoint in the AG arm demonstrates the need for an appropriate comparator in studies of this type.

Trial registration

ClinicalTrials.gov NCT02730572

Mixed Approach Retrospective Analyses of Suicide and Suicidal Ideation for Brand Compared with Generic Central Nervous System Drugs

INTRODUCTION

Several different types of drugs acting on the central nervous system (CNS) have previously been associated with an increased risk of suicide and suicidal ideation (broadly referred to as suicide). However, a differential association between brand and generic CNS drugs and suicide has not been reported.

OBJECTIVES

This study compares suicide adverse event rates for brand versus generic CNS drugs using multiple sources of data.

METHODS

Selected examples of CNS drugs (sertraline, gabapentin, zolpidem, and methylphenidate) were evaluated via the US FDA Adverse Event Reporting System (FAERS) for a hypothesis-generating study, and then via administrative claims and electronic health record (EHR) data for a more rigorous retrospective cohort study. Disproportionality analyses with reporting odds ratios and 95% confidence intervals (CIs) were used in the FAERS analyses to quantify the association between each drug and reported suicide. For the cohort studies, Cox proportional hazards models were used, controlling for demographic and clinical characteristics as well as the background risk of suicide in the insured population.

RESULTS

The FAERS analyses found significantly lower suicide reporting rates for brands compared with generics for all four studied products (Breslow-Day P < 0.05). In the claims- and EHR-based cohort study, the adjusted hazard ratio (HR) was statistically significant only for sertraline (HR 0.58; 95% CI 0.38-0.88).

CONCLUSION

Suicide reporting rates were disproportionately larger for generic than for brand CNS drugs in FAERS and adjusted retrospective cohort analyses remained significant only for sertraline. However, even for sertraline, temporal confounding related to the close proximity of black box warnings and generic availability is possible. Additional analyses in larger data sources with additional drugs are needed.