Comparative effectiveness of generic versus brand-name antiepileptic medications

Generic switching: Do future physicians in Jordan have enough knowledge and a positive attitude?

Background: Generic switching is a policy that has shown success in minimising pharmaceutical costs. It has also been used to mitigate recurrent and sudden drug shortages. Not all countries have policies that allow pharmacists to switch to generic drugs independently. In Jordan, only pharmacists at Ministry of Health hospitals automatically switch to generics if doctors had not already done INN prescribing. Objectives: This study targeted medical students to assess their experience with generic switching as patients, their knowledge of the subject as students, and their attitude towards it as future prescribers and policymakers. Methods: This is a descriptive, cross-sectional study conducted online. Eligibility criteria were being a fourth, fifth, or sixth-year medical school student enrolled at any of the six Jordanian universities. The questionnaire was developed by the researchers after a careful review of the relevant literature. Results: Three hundred and ninety students responded to the online questionnaire. Most participants were females (244, 62.6%), senior students in their final (6th) year (162, 41.5%) and with very good academic achievement (166, 42.6%). The highest knowledge scores concerned patient rights (0.73/1.00), followed by knowledge about monitoring after generic switching (0.66/1.00), and patients with known drug allergies (0.66/1.00). Almost half of the participants believe that pharmacists should not be given the right to do generic switching and only 16% stated that they would choose generic drugs if they needed treatment in the future. Multivariate linear regression analysis showed that significant predictors of knowledge were gender, GPA, and family income. No correlations were found between participants' knowledge scores and their attitudes towards giving pharmacists the right to independently switch drugs, or whether they would accept a substitute from pharmacists rather than having to refer to the physician. Conclusion: Medical students in Jordan lack sufficient knowledge about generic switching. Students need to be more aware of the current policies and regulations of this practice, and the role of each healthcare worker involved in it. They also need to have a more positive attitude toward generic drugs and generic switching practice to facilitate its future implementation.

Bioequivalence, Drugs with Narrow Therapeutic Index and the Phenomenon of Biocreep: A Critical Analysis of the System for Generic Substitution

The prescription of generic drugs represents one of the main cost-containment strategies of health systems, aimed at reducing pharmaceutical expenditure. In this context, most regulatory authorities encourage or obligate dispensing generic drugs because they are far less expensive than their brand-name alternatives. However, drug substitution can be critical in particular situations, such as the use of drugs with a narrow therapeutic index (NTI). Moreover, generics cannot automatically be considered bioequivalent with each other due to the biocreep phenomenon. In Italy, the regulatory authority has established the Transparency Lists which include the medications that will be automatically substituted for brand-name drugs, except in exceptional cases. This is a useful tool to guide prescribers and guarantee pharmaceutical sustainability, but it does not consider the biocreep phenomenon.

Clinical Outcome and Medical Cost of Originator and Generic Antihypertensive Drugs: A Population-Based Study in Yinzhou, China

Background: The substitution of generic drugs can effectively alleviate the rapid growth of drug costs; however, the clinical effectiveness and medical costs of originator products and generics were barely studied in China.

Objectives: To compare the effectiveness of antihypertensive drugs and hypertension-related medical costs between originator and generic initiators in Yinzhou, China.

Methods: We conducted a population-based retrospective cohort study using the Chinese Electronic Health Records Research in Yinzhou (CHERRY), from July 1, 2011, to December 31, 2018. Hypertension patients initiating with originator products were compared with patients initiating with generic counterparts. We used 1:1 propensity score matching to pair the two groups based on sociodemographic, clinical, and health service utilization variables. Cox proportional regression was adopted to compare the rate of hospitalization for hypertension-related cardiovascular disease between matched originator and generic initiators. Wilcoxon matched-pairs signed-rank test was used to compare annual hypertension-related medical costs.

Results: Matched pairs (10,535) of patients were included in the comparative study of originator products and generics, corresponding to seven antihypertensive drugs including amlodipine, felodipine, nifedipine, irbesartan, losartan, valsartan, and metoprolol. The average age of patients included in the analysis was around 60 years (originator vs. generics initiators: from 59.0 vs. 59.1 years in losartan to 62.9 vs. 63.6 years in nifedipine). Higher hospitalization rates among originator initiators were observed for three calcium channel blockers (hazard ratio[95% CI]: amlodipine, 3.18[1.43, 7.11]; felodipine, 3.60[1.63, 7.98]; and nifedipine, 3.86[1.26, 11.81]; respectively). The remaining four out of seven drugs of the clinical endpoint estimates showed comparable outcomes between originator products and generics (hazard ratio[95% CI]: irbesartan, 1.19[0.50, 2.84]; losartan, 1.84[0.84, 4.07]; valsartan, 2.04[0.72, 5.78]; and metoprolol, 1.25[0.56, 2.80]; respectively). Higher median annual hypertension-related medical costs were observed in originator initiators (all p < 0.001), except for metoprolol (p = 0.646).

Conclusion: We observed comparable or even better clinical outcomes and less medical cost associated with the use of antihypertensive generics compared to originator counterparts. This could help increase patient and provider confidence in the efficacy of generic medicines to manage hypertension diseases.

Considerations over a Case of Suspected Therapeutic Failure in Pediatric Patients after Switching Valproate Manufacturers

Introduction: Product switching followed by suspected adverse events are common and unsettling for antiepileptic drugs. The objective of this case study was to describe the investigation performed after report of suspected therapeutic failure in pediatric patients following a switch to a different valproate manufacturer and identify strategies concerning medication management for improving therapeutic outcomes. Case description: It was reported that different pediatric patients' condition changed (agitation/ seizures) after refilling the same drug prescription (sodium valproate syrup) from a different manufacturer. Medical staff reported a suspected therapeutic failure and some units of the product batch associated with the problem were seized by the local Post-marketing Surveillance Service for investigation of potential quality deviations. The seized units were evaluated by the State's Surveillance Laboratory, nevertheless, drug potency was found to be 98.7%. Conclusion: We consider that the reported event could be associated with aspects of medication use, i.e. potential dose measurement deviations resulting from remaining of residual liquid in the cup or eventual delay at prescription refilling process and consequential - even though brief - pharmacotherapy discontinuity. Patient education and counseling by pharmacists are essential for preventing drug-related problems and enhancing positive outcomes of pharmacotherapy.

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.

Use of antiseizure medications and safety of branded versus generic formulations: A comparative study on Tuscan administrative databases

PURPOSE

To assess patterns of use of antiseizure medications (ASMs) and to compare the safety of generic versus branded formulations in terms of admission to hospital or to emergency department (ED).

METHODS

We conducted a drug utilization study with a propensity score-matched design using the administrative databases of the Italian Tuscany region. New users of ASMs during 2015 with no history of neoplasia were considered and their first prescription was classified as: available only as branded (only-B-ASM); branded with generic available (B-ASM); and generic (G-ASM). Patients with G-ASM first prescription were matched with four patients with B-ASM prescription. Participants were followed up for one year or until the date of death or diagnosis of neoplasia. Cox regression models were fitted to estimate the risk of admission to hospital or ED.

RESULTS

We identified 36,601 ASM new-users, including 2094 (6.4%) with only-B-ASM as first prescription, 24,588 (74.9%) with B-ASM, and 5788 (17.6%) with G-ASM. We found no differences in the risk of admission to hospital or ED (Hazard Ratio (HR), 0.92; 95% Confidence Interval (CI), 0.85-1.02) among users of generic ASMs compared to those using branded ASMs.

CONCLUSIONS

In our study population, generic ASMs were used less than branded ones. The similarity in the safety of branded and generic formulations suggests that generic ASMs could be the preferred formulation in current clinical practice resulting in a substantial decrease in the cost of treatment.

Impact of Formulary Restrictions on Antiepileptic Drug Dispensation Outcomes

INTRODUCTION

The aim of this analysis was to assess the relationship between formulary restrictions and antiepileptic drug (AED) dispensation in patients with focal seizure (FS).

STUDY DESIGN

A retrospective cohort analysis was conducted using data from Symphony Health's Integrated Dataverse® (1 April 2015-30 June 2018).

METHODS

This study included two patient populations: the overall patient population (N = 54,097) and a pediatric population (< 18 years) (N = 12,610). Cohorts were defined based on approval or rejection of the index AED claim. Study outcomes were prescription life cycle analysis, proportion of patients with dispensation, time to dispensation, and likelihood of successful dispensation. A multivariable Cox proportional hazards model was estimated to study the association between formulary restriction and likelihood of successful AED dispensation.

RESULTS

Among patients in the overall population with a rejected claim (n = 9133), 8.0% did not receive any AED and 77.6% received approval for the index AED following an appeal. Among the pediatric patients with a rejected claim (n = 3081), 6.0% did not receive any AED and 81.7% received approval for the index AED after an appeal. In both populations, formulary restrictions were associated with significant delays in index AED dispensation (6.9 and 5.3 days, respectively; P  < 0.0001 for each population), compared to approved AED claims. In the overall and pediatric populations, formulary-related rejections of AEDs were associated with a 35% (hazard ratio [HR] 0.65; 95% confidence interval [CI] 0.64-0.66; P  < 0.0001) and 27% (HR 0.73; 95% CI 0.69-0.76; P  < 0.0001) lower likelihood of successful dispensation of the index AED, respectively.

CONCLUSIONS

Formulary restrictions of AEDs were associated with significant delays in treatment and significantly lower likelihood of successful AED dispensation in patients with FS.

Effects of generic exchange of solid oral dosage forms in neurological disorders: a systematic review

Background Generic drug exchange is common practice in most healthcare systems. While generics certainly contribute to economic savings, the altered drug formulation might be associated with potential therapeutic problems. Given the narrow therapeutic windows in neurologic indications, any detrimental effect on the therapy can lead to significant consequences. Aim of the review This review aims to investigate potential problems related to a switch from brand-name to generic or from generic to generic drug products in patients with neurologic diseases. Method The review was conducted following the PICO framework and the PRISMA guidelines. MEDLINE and Scopus databases were searched for articles published in English and German language between January 1, 1995 and October 17, 2018. Studies included in this review were randomized controlled studies, reviews, systematic reviews, overviews, cohort studies and case-control studies. Studies excluded were letters, comments, authors view, congress or seminar papers and studies with a focus on economic impact or costs. Results were synthesized qualitatively. The primary outcomes were pharmacokinetic parameters such as the area under the curve (AUC), the peak serum concentration (c_max) or the time at which c_max is observed (t_max). Results The search identified 67 studies with a great variety of endpoints and study designs. The leading indication was epilepsy. Two small RCTs were found on lamotrigine switch. Analysis of the other studies found no significant differences in pharmacokinetic parameters when switching to generic drugs. A more heterogeneous picture was revealed regarding hospitalizations, breakthrough seizures, failure of therapy, adherence and patient concerns. Conclusion While most reports were of poor quality, lamotrigine was the drug with the best available data. Summarizing the results of the available studies, pharmacokinetic parameters of antiepileptic drugs show low deviation. In contrast, data on clinical parameters are less consistent. Some studies found increased seizure frequencies and adverse-drug events, while others showed no complications. Adherence and patient satisfaction seemed to be impaired. In daily practice, generic exchange in epilepsy should be a carefully balanced decision, conducted with great caution. Further research is needed, especially regarding neurologic indications other than epilepsy.

Comparative effectiveness of branded vs. generic versions of antihypertensive, lipid-lowering and hypoglycemic substances: a population-wide cohort study

Generic medications offer substantial potential cost savings to health systems compared to their branded counterparts. In Europe and the US, they are only approved if they are bioequivalent to the respective originator product. Nevertheless, the lack of clinical outcomes is sometimes used as the reason for hesitancy in prescribing generics. We performed an observational retrospective study on 17 branded vs. generic pharmaceutical substances for the treatment of hypertension/heart failure, hyperlipidemia, and diabetes mellitus in a dataset of 9,413,620 insured persons, representing nearly the full population of Austria, from 2007 to 2012. We compared generic vs. branded medications using hazard ratios for all-cause death and major adverse cardiac and cardiovascular events (MACCE) as outcomes of interest. Using patient demographics, health characteristics from hospitalization records, and pharmacy records as covariates, we controlled for confounding in Cox models through inverse probability of treatment weighting (IPTW) using high-dimensional propensity scores. We observed that the unadjusted hazard ratios strongly favor generic drugs for all three pooled treatment indications (hypertension/heart failure, hyperlipidemia, diabetes mellitus), but were attenuated towards unity with increasingly larger covariate sets used for confounding control. We found that after IPTW adjustment the generic formulation was associated with significantly fewer deaths in 10 of 17 investigated drugs, and with fewer MACCE in 11 of 17 investigated drugs. This result favoring generic drugs was also present in a number of sub-analyses based on gender, prior disease status, and treatment discontinuation. E-value sensitivity analyses suggested that only strong unmeasured confounding could fully explain away the observed results. In conclusion, generic medications were at least similar, and in some cases superior, to their branded counterparts regarding mortality and major cardiovascular events.

Relationship of antiepileptic drugs to generic brittleness in patients with epilepsy

PURPOSE

The purpose of the study was to assess if any antiepileptic drug (AED) was associated with patients being generic brittle (GB) and if any specific AED caused - and was not merely associated with - more frequent switch problems.

METHODS

Chi square and binary logistical regression analysis were performed, using a previously described study in patients with epilepsy who were routinely followed at the University of Maryland epilepsy outpatient clinic in Baltimore, Maryland. Determination of generic brittleness mirrored clinical practice and included patient opinion about generic formulations, usually based on a history of worsened seizures or side effects with prior AED formulation switching. The dataset included a total of 148 patients, who took 30 different AED formulations. Patients collectively took 530 AED formulation products.

RESULTS

Taking lamotrigine immediate release (IR) tablets was associated with a greater probability of being GB and tended to cause more frequent switch problems. Interestingly, six AEDs - Vimpat tablet, carbamazepine IR tablet, phenobarbital (any formulation), gabapentin capsule, Lyrica capsules, and phenytoin (any formulation) - were associated with a reduced probability of being GB, although perhaps not through greater efficacy and tolerability, or better formulation quality. Since tablet and capsule appearance may influence patient perceptions and clinical outcomes, it was observed that the six AEDs less associated with being GB also tended to have fewer generics, and hence possibly lessen treatment uncertainties from the patient perspective. A patient taking more AEDs had significantly increased odds of having a switch problem. An additional observation was that, when a generic was available for their most problematic AED, GB patients took a generic AED only 50% of the time, while not GB patients took a generic AED all the time.

CONCLUSIONS

Taking lamotrigine IR tablets was associated with a greater probability of being GB and tended to cause more frequent switch problems than other AEDs in this cohort of patients. Six AEDs were associated with a reduced probability of being GB. The lower number of different generics for these six drugs may result in greater patient certainty in medication identity, due to greater consistency in medication color, shape, and size, and hence less generic skepticism or generic brittleness. Also, patients taking more AEDs showed increased odds of a switch problem.

The Portuguese generic medicines market: What's next?

Brand-name medicines have dominated the Portuguese market for several decades with unquestionable exclusivity. This resulted particularly from the absence of a requirement of prescriptions by international non-proprietary name. To promote the enhancement of both efficiency and sustainability in the health system, the Portuguese government introduced the generics in Portugal by the 90 s. However, only in the first decade of the 21^st century were some policies implemented to increase their market share. Although some expectations were created, the use of generics has increased moderately during that period, in which policies to promote them were consolidated by imposing the austerity principles in the midst of the economic and social crisis. This study analyses the main policy measures already implemented as well as the incentives created for the replacement of brand-name medicines with generics. In addition, the present study also makes some recommendations to promote a broader and better use of generics in Portugal.

Risk of hospitalization among patients with epilepsy using long versus short half-life adjunctive antiepileptic drugs

INTRODUCTION

While antiepileptic drugs (AEDs) remain the primary treatment for epilepsy, many patients continue to have seizures. Uncontrolled seizures may be related to AED half-life, since short half-life (SHL) AEDs require more frequent dosing compared with the simplified regimens of long half-life (LHL) AEDs. Long half-life AEDs may also improve seizure control by extending missed dose forgiveness periods. The value of LHL AEDs may be assessed as reduced healthcare utilization. The study's objective was to examine the impact of adding an LHL versus SHL adjunctive AED on the risk of hospitalizations in patients with uncontrolled epilepsy.

METHODS

This was a retrospective, longitudinal cohort study using the Symphony Health Solution Patient Integrated Dataverse. Patients ≥12 years old with uncontrolled epilepsy (≥2 medical claims ≥30 days apart) were identified during a study period (8/1/2012-7/31/2017). Patients were selected if they were subsequently initiated an adjunctive AED (excluding modified release formulations), and the prescription date served as the index. Patients were stratified into two mutually exclusive cohorts based on the index AED half-life (≤20 versus >20 h). Poisson regressions with robust error variances were performed for the relative risks (RRs) of all-cause, epilepsy-related, and injury-related hospitalizations.

RESULTS

A total of 4984 patients were identified (2705 in the LHL and 2279 in the SHL cohort). Compared with those in the SHL cohort, patients in the LHL cohort were significantly younger [mean (SD, years): 43.9 (18.5) versus 49.2 (17.2), p < 0.001] and were less comorbid [mean (SD) of Charlson comorbidity index: 1.2 (1.8) versus 1.8 (2.2), p < 0.001]. In the one-year postindex date, adjusting for group differences, the risks of both all-cause and epilepsy-related hospitalizations were significantly lower in the LHL cohort than in the SHL cohort [all-cause: 0.84 (95% CI: 0.76-0.93), p = 0.0006; epilepsy-related: 0.83 (0.73-0.94), p = 0.0046].Injury-related hospitalizations did not differ between LHL and SHL cohorts.

CONCLUSION

In patients with uncontrolled epilepsy who were initiated on an adjunctive AED, the choice of an LHL versus SHL was associated with significantly lower risks of all-cause and epilepsy-related hospitalizations.

Evaluating statistical approaches to leverage large clinical datasets for uncovering therapeutic and adverse medication effects

Motivation

Phenome-wide association studies (PheWAS) have been used to discover many genotype-phenotype relationships and have the potential to identify therapeutic and adverse drug outcomes using longitudinal data within electronic health records (EHRs). However, the statistical methods for PheWAS applied to longitudinal EHR medication data have not been established.

Results

In this study, we developed methods to address two challenges faced with reuse of EHR for this purpose: confounding by indication, and low exposure and event rates. We used Monte Carlo simulation to assess propensity score (PS) methods, focusing on two of the most commonly used methods, PS matching and PS adjustment, to address confounding by indication. We also compared two logistic regression approaches (the default of Wald versus Firth's penalized maximum likelihood, PML) to address complete separation due to sparse data with low exposure and event rates. PS adjustment resulted in greater power than PS matching, while controlling Type I error at 0.05. The PML method provided reasonable P-values, even in cases with complete separation, with well controlled Type I error rates. Using PS adjustment and the PML method, we identify novel latent drug effects in pediatric patients exposed to two common antibiotic drugs, ampicillin and gentamicin.

Availability and implementation

R packages PheWAS and EHR are available at https://github.com/PheWAS/PheWAS and at CRAN (https://www.r-project.org/), respectively. The R script for data processing and the main analysis is available at https://github.com/choileena/EHR.

Supplementary information

Supplementary data are available at Bioinformatics online.

Nocebo in Biosimilars and Generics in Neurology: A Systematic Review

Background: Nocebo refers to adverse events related to patients’ negative expectations and previous experiences, mediated by several neurobiological pathways within the brain. It is common among neurological patients and affects adherence and treatment outcomes, representing a real clinical challenge.

Methods: We conducted a systematic search based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines in MEDLINE database, using several keywords for studies that can be processed to investigate the magnitude of nocebo in generics and biosimilars used in the most common neurological diseases. The aim was to estimate its size and suggest strategies to minimize its prevalence in clinical trials and practice.

Results: Of a total of 2,606 identified articles, after criteria-based selection, 35 studies were included for analysis. Overall, there was vast heterogeneity across the studies concerning population, study design, and outcomes. Nocebo response could be estimated only in one double-blind randomized trial of generic glatiramer acetate in relapsing remitting multiple sclerosis that included a placebo arm. In this trial, no significant differences observed between the three arms (innovator, bioequivalent, and placebo) in favorable and unfavorable outcomes. In the open-label phase of the trial, an increased withdrawal rate was recorded in patients switched from placebo to bioequivalent (8.4%) that may be related to nocebo. In other open-label and real-world studies evaluating biosimilars or generics for brain disorders, a similar indirect nocebo effect is assuming by several investigators. Also, knowledge gaps between health-care providers and patients exist towards generics and biosimilars.

Conclusions: Despite its presence, the true burden of the nocebo response and effect cannot be accurately estimated in existing studies with generics and biosimilars in neurological diseases. Targeted strategies for clinical trials’ design are needed in order to measure the exact nocebo’s size.

A Survey of Patients' Perceptions of Pill Appearance and Responses to Changes in Appearance for Four Chronic Disease Medications

BACKGROUND

Generic versions of a drug can vary in appearance, which can impact adherence.

OBJECTIVE

To assess the preferences, perceptions, and responses of patients who experienced a change in the appearance of a generic medication.

DESIGN

Cross-sectional survey of patients from a large commercial health plan.

PARTICIPANTS

Adults receiving generic versions of lisinopril, fluoxetine, lamotrigine, or simvastatin who experienced a change in the color or shape of their pills between March 2014 and November 2015.

MAIN MEASURES

Likert-scale responses to questions concerning perceptions of generic drug safety and effectiveness, reliance on and preferences for pill appearance, and responses to pill appearance changes. Multivariable logistic regression-modeled predictors of seeking advice and adjusting use following a pill appearance change.

KEY RESULTS

Of 814 respondents (response rate = 41%), 72% relied on pill appearance to ensure they took the correct medication. A similar percentage wanted their pills to remain the same color (72%), shape (71%), and size (75%) upon refill, but 58% would not have paid a $1 premium on a $5 co-pay to ensure such consistency. Most respondents (86%) wanted their pharmacists to notify them about pill appearance changes, but only 37% recalled such notification; 21% thought they received the wrong medication, and 8% adjusted medication use. Younger respondents (18-33 vs. 50-57 years) were more likely to seek advice (odds ratio [OR] = 1.91; 95% confidence interval [CI],1.02-3.59), and respondents with lower household income (< $30,000 vs. > $100,000) were more likely to adjust medication use (OR = 3.40; 95% CI,1.09-10.67).

CONCLUSIONS

Requiring uniform pill appearance may help increase adherence but presents challenges. Standardized pharmacy notification and education policies may be a more feasible short-term solution.

Switching medication products during the treatment of psychiatric illness

BACKGROUND

The common practice of switching between branded (reference) medications and their corresponding generic products, between generic products, or even from a generic product to a branded medication during the treatment of central nervous system (CNS) disorders may compromise efficacy and/or tolerability.

METHODS

We assessed the published literature from March 1, 2010 through June 30, 2017 via PubMed using the MeSH term 'generics, drugs' alone and in combination with class-specific terms (e.g., 'anticonvulsants', 'mood stabilisers'), for studies detailing outcomes following product switches.

RESULTS

Although some studies comparing the initiation of reference versus generic drugs suggest equivalence between products, several studies detailing a switch between reference and generic products describe reductions in efficacy, reduced medication adherence and persistence, and increased overall health care resource utilization and costs associated with generic substitution.

CONCLUSION

When product switches are considered, they should only proceed with the full knowledge of both patient and provider.

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.

Evaluation of Socioeconomic Status Indicators for Confounding Adjustment in Observational Studies of Medication Use

Methodologic research evaluating confounding due to socioeconomic status (SES) in observational studies of medications is limited. We identified 7,109 patients who initiated brand or generic atorvastatin from Medicare claims (2011-2013) linked to electronic medical records and census data. We created a propensity score (PS) containing only claims-based covariates and augmented it with additional claims-based proxies for SES, ZIP code, and block group level SES. Cox models with PS fine-stratification and weighting were used to compare rates of a cardiovascular end point and emergency department visits. Adjustment with only claims-based variables substantially improved balance on all SES variables compared with the unadjusted. Although inclusion of SES in PS models further improved balance on SES variables compared with models with claims-based covariates only, it did not materially change point estimates for either outcome. Inclusion of claims-based proxies may mitigate confounding by SES when aggregate-level SES information is unavailable.

Exploring knowledge and perceptions on generic drugs of final year pharmacy school students in Greece

Objectives: The economic crisis in Greece has triggered an extensive public debate about the use of generic drugs (generics). Despite their cost-saving potential, generic market penetration remains very low. This raises questions on awareness of, perception on and preference for generics by health-care professionals and patients. This is a descriptive study on the level of knowledge and attitudes towards generics of final year pharmacy school students in Greece. Methods: An electronic questionnaire was distributed to 173 senior pharmacy school students in three Universities in Greece. Responses were submitted electronically. Results: The majority of students knew that generics contain the same active ingredient as the originator products and are cheaper. Students were somehow concerned with safety and efficacy of generics. The majority of students agreed that pharmacists should probably recommend the use of generics, and indicated that prescribing and dispensing practices would largely depend on the profit margin. Despite more than half of the students expressing a positive attitude towards generics, they were inadequately educated on their features. Conclusion: It is critical to improve knowledge of and preference for generics amongst health-care professionals from early on if to build the trust required to increase generic market penetration and achieve measurable savings in pharmaceutical expenditure.

Generic Drugs in the United States: Policies to Address Pricing and Competition

The cost of prescription drugs in the United States continues to be a source of concern for patients, caregivers, and policymakers. Drug prices typically decline rapidly once generic drugs receive US Food and Drug Administration (FDA) approval and enter the market, but the past decade has witnessed rising costs and shortages of generic drugs. We describe the strategies used by brand-name manufacturers to undermine generic competition and the reasons underlying the price increases of off-patent drugs, some of which continue to lack any competition from generic versions, and others that have increased in price despite having generic versions. We discuss the FDA's role in addressing drug prices and promoting competition, including recent agency policies to modify its process of reviewing generic drug applications and to prioritize applications for off-patent drugs with few competitors. We also examine proposed policy solutions and research areas that could help address the price increases of off-patent drugs.

Quality and In-Use Stability Comparison of Brand and Generics of Extended-Release Phenytoin Sodium Capsules

The objective of the present study was to understand quality of brand and generic products of phenytoin sodium by in vitro methods. Three commercial products were selected for the study, 1 brand and 2 generics (product-A, product-B, and product-C). Products were repacked in pharmacy vials and stored for 12 weeks at 30°C/75% RH to simulate in-use conditions. The products were examined visually and microscopically for morphologic changes, spectroscopic and diffractometric methods for chemical changes, and dissolution, assay, and impurities for performance evaluation. Capsules content of the product-A turned yellowish to dark orange color from initial white powder, which indicated a possible chemical interaction between lactose and the drug in addition to disproportionation. This was supported by pH, microscopic, spectroscopic, and X-ray diffraction data. Product-A failed to meet United States Pharmacopoeia dissolution specification of 75% in 120 min after 2-weeks whereas product-B and product-C failed at 6-weeks of in-use stability conditions exposure. Furthermore, product-A also failed to meet United States pharmacopoeia assay and impurities specifications in 12 weeks in-use period. In summary, this study indicated salt disproportionation, chemical interactions, and phase transformations of drug and excipients in the commercial products of phenytoin sodium, which may affect the clinical performance of the product.

Exploring generic brittleness and the demographic factors for its susceptibility in patients with epilepsy

PURPOSE

The purpose of this study was to provide an algorithm for generic brittleness and to elucidate the demographic factors that anticipate generic brittleness for patients with epilepsy.

METHODS

This exploratory, observational, and nontherapeutic study was conducted in patients with epilepsy who were routinely followed at the University of Maryland epilepsy outpatient clinic in Baltimore, Maryland. Patients were taking at least one antiepileptic drug (AED) for treatment of epilepsy. Based on patient interview and medical history, 12 demographic factors were collected. Each patient was assessed to be either generic brittle (GB) or not GB. Demographic factors were subjected to binary logistical regression and other statistical tests, to elucidate determinants of GB status.

RESULTS

N = 148 patients completed the study. An algorithm to define whether a patient was GB or not GB was devised. The two elements that defined GB status are as follows: patient opinion about generics and (if needed) whether patients were currently taking brand or generic of their most problematic AED. About 40% of patients were GB. From binary logistical regression, two demographic factors that contributed to patients being GB were whether a patient was currently taking a problem AED and total number of current medications for a patient, with odds ratios of 4.06 (95% confidence interval [CI] from 1.53 to 10.81) and 1.10 (95% CI from 1.003 to 1.21), respectively. Of the patients on a problem AED, 46.9% were GB, while only 18.2% of patients not currently on a problem AED were GB. The total number of current medications ranged from 1 to 22, with mode of four medications. From regression, for each additional medication that a patient took, the odds of being GB increased 1.10-fold. Although patient seizure and adverse event history was not employed to define GB status, being GB was associated with less seizure control and greater adverse events.

CONCLUSIONS

An algorithm for generic brittleness was derived, and about 40% of patients were GB, usually due to prior history of a switch problem. Two demographic factors favored patients being GB: whether the patient was currently taking a problem AED and the total number of current medications.

Potential Savings in Medicare Part D for Common Urological Conditions

INTRODUCTION

Millions of patients take prescription medications each year for common urological conditions. Generic and brand-name drugs have widely divergent pricing despite similar therapeutic benefit and side effect profiles. We examined prescribing patterns across provider types for generic and brand-name drugs used to treat 3 common urological conditions, and estimated economic implications for Medicare Part D spending.

METHODS

We extracted 2014 prescription claims and payments from Medicare Part D and categorized oral medications used to treat 3 urological conditions, namely benign prostatic hyperplasia, erectile dysfunction and overactive bladder. We examined claims and payments for each medication among urologists and nonurologists. Lastly, we estimated potential savings by selecting a low cost or generic drug as a cost comparator for each class.

RESULTS

There were significant differences in prescribing patterns across these conditions, with urologists prescribing more brand-name and expensive medications (p <0.001). The total potential savings related to prescriptions of more expensive and nongeneric drugs in 2014 was $1 billion (benign prostatic hyperplasia $348,454,910, erectile dysfunction $10,211,914 and overactive bladder $698,130,833). These potential savings comprised 53% of the total spending for these medications in 2014.

CONCLUSIONS

Within Medicare Part D the potential savings associated with generic substitution for higher cost and nongeneric drugs for 3 common urological conditions surpassed $1 billion, with urologists more likely to prescribe brand-name and more expensive drugs. Increasing low cost and generic drug use where available evidence of efficacy is equivocal represents a promising policy target to optimize prescription drug spending.

The challenges of assessing effectiveness of lacosamide using electronic medical record databases

PURPOSE

Electronic health record (EHR) databases are a potential source for conducting research to generate real world evidence on patient outcomes. The objective of the study was to evaluate the feasibility of using EHR data to assess seizure outcomes in patients treated with lacosamide (LCM) monotherapy.

METHODS

This was a retrospective cohort study conducted using the Optum clinical EHR database. The study sample comprised patients ≥17 years of age with epilepsy or seizures and treated with LCM monotherapy between 1 January 2009 and 31 December 2013. Structured and unstructured data from prescribed medication and abstracted physician note records were used to identify patients with epilepsy treated with LCM monotherapy and measure seizure frequency outcomes. The index date was the first date of LCM monotherapy, with a 6-month baseline period. Patients were observed for up to 12 months beginning on the index date (follow-up period). The EHR data were not sufficient to compute days supply and explicit duration of LCM and other antiepileptic drug (AED) therapies; therefore, LCM monotherapy was estimated from prescription dates of AEDs. Outcomes were change in seizures per month or change in seizure frequency category from baseline to follow-up. Descriptive statistics were used to describe baseline characteristics and study outcomes.

RESULTS

A total of 10,988 patients with at least one LCM prescription were identified during the study period, 470 of whom met all the selection criteria and were included in the study sample. Although many patients had abstracted physician note records that referred to their seizures, only 3.2% of the patients had seizure frequency information that could be used to quantify the number of seizures per month in both the baseline and follow-up periods; thus, this information could not be used to assess the effectiveness of LCM monotherapy on seizure outcomes.

CONCLUSION

Lacosamide monotherapy effectiveness was not estimated because the EHR prescription record data did not have sufficient information on days supply. Additionally, most patients' records did not contain adequate information to allow for evaluation of quantitative changes in seizure frequency based on the number of seizures per month. More studies are needed to validate these study findings.

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.

Drug promotional activities in Nigeria: impact on the prescribing patterns and practices of medical practitioners and the implications

OBJECTIVE

Pharmaceutical companies spend significant amount of resources on promotion influencing the prescribing behavior of physicians. Drug promotion can negatively impact on rational prescribing, which may adversely affect the quality of patient care. However, little is known about these activities in Nigeria as the most populous country in Africa. We therefore aimed to explore the nature of encounters between Nigerian physicians and pharmaceutical sales representatives (PSRs), and how these encounters influence prescribing habits.

METHODS

Cross-sectional questionnaire-based study conducted among practicing physicians working in tertiary hospitals in four regions of Nigeria.

RESULTS

176 questionnaires were completed. 154 respondents (87.5%) had medicines promoted to them in the previous three months, with most encounters taking place in outpatients' clinics (60.2%), clinical meetings (46%) and new medicine launches (17.6%). Information about potential adverse effects and drug interactions was provided in 41.5%, and 27.3% of cases, respectively. Food, in the form of lunch or dinner, was the most common form of incentive (70.5%) given to physicians during promotional activities. 61% of physicians felt motivated to prescribe the drug promoted to them, with the quality of information provided being the driving factor. Most physicians (64.8%) would agree to some form of regulation of the relationship between medical doctors and the pharmaceutical industry.

CONCLUSION

Interaction between PSRs and physicians is a regular occurrence in Nigeria, influencing prescribing practices. Meals and cheap gifts were the most common items offered to physicians during their encounters with PSRs. The need for some form of regulation by professional organizations and the government was expressed by most respondents to address current concerns.

Tiered co-payments, pricing, and demand in reference price markets for pharmaceuticals

Health insurance companies curb price-insensitive behavior and the moral hazard of insureds by means of cost-sharing, such as tiered co-payments or reference pricing in drug markets. This paper evaluates the effect of price limits - below which drugs are exempt from co-payments - on prices and on demand. First, using a difference-in-differences estimation strategy, we find that the new policy decreases prices by 5 percent for generics and increases prices by 4 percent for brand-name drugs in the German reference price market. Second, estimating a nested-logit demand model, we show that consumers appreciate co-payment exempt drugs and calculate lower price elasticities for brand-name drugs than for generics. This explains the different price responses of brand-name and generic drugs and shows that price-related co-payment tiers are an effective tool to steer demand to low-priced drugs.

Generic Versions of Narrow Therapeutic Index Drugs: A National Survey of Pharmacists' Substitution Beliefs and Practices

Small changes in bioavailability of narrow therapeutic index (NTI) drugs can alter clinical outcomes, raising concern over generic NTI substitution. We surveyed pharmacists to identify their perceptions of generic NTI drugs, their frequency of performing generic NTI substitution, and predictors of this behavior. Of 710 respondents (33% response rate), 87% perceived generic NTI drugs as effective as their brand-name versions and 94% as safe. Whereas 82% almost always performed generic NTI substitution for initial prescriptions, only 60% did for refills. Pharmacists in non-chain settings (odds ratio (OR) = 2.37; 95% confidence interval (CI) = 1.40-4.02), in practice longer (per year OR = 1.04; 95% CI = 1.02-1.06), in states with affirmative patient consent laws (OR = 1.88; 95% CI = 1.06-3.32), and in states with NTI-specific substitution requirements (OR = 1.95; 95% CI = 1.16-3.26) were more likely not to substitute initial prescriptions. Education of non-chain and veteran pharmacists and elimination of affirmative patient consent and NTI-specific substitution requirements could increase generic NTI substitution.

Comparative persistence of antiepileptic drugs in patients with epilepsy: A STROBE-compliant retrospective cohort study

We compared persistence of antiepileptic drugs (AEDs) including carbamazepine, oxcarbazepine, gabapentin, lamotrigine, topiramate, valproic acid, and phenytoin in an Asian population with epilepsy.A retrospective cohort study was conducted by analyzing Taiwan's National Health Insurance Research Database (NHIRD). Adult epilepsy patients newly prescribed with AEDs between 2005 and 2009 were included. The primary outcome was persistence, defined as the treatment duration from the date of AED initiation to the date of AED discontinuation, switching, hospitalization due to seizure or disenrollment from databases, whichever came first. Cox proportional hazard models were used to estimate the risk of non-persistence with AEDs.Among the 13,061 new users of AED monotherapy (mean age: 58 years; 60% men), the persistence ranged from 218.8 (gabapentin) to 275.9 (oxcarbazepine) days in the first treatment year. The risks of non-persistence in patients receiving oxcarbazepine (adjusted hazard ratio [HR], 0.78; 95% CI, 0.74-0.83), valproic acid (0.88; 0.85-0.92), lamotrigine (0.72; 0.65-0.81), and topiramate (0.90; 0.82-0.98) were significantly lower than in the carbamazepine group. Compared with carbamazepine users, the non-persistence risk was higher in phenytoin users (1.10; 1.06-1.13), while gabapentin users (1.03; 0.98-1.09) had similar risk. For risk of hospitalization due to seizure and in comparison with carbamazepine users, oxcarbazepine (0.66; 0.58-0.74) and lamotrigine (0.46; 0.35-0.62) users had lower risk, while phenytoin (1.35; 1.26-1.44) users had higher risk. The results remained consistent throughout series of sensitivity and stratification analyses.The persistence varied among AEDs and was better for oxcarbazepine, valproic acid, lamotrigine, and topiramate, but worse for phenytoin when compared with carbamazepine.