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A comparison of the intrasubject variation in drug exposure between generic and brand-name drugs: a retrospective analysis of replicate design trials.

ABSTRACT: AIMS:The aim of the present study was to investigate whether differences in total and peak drug exposure upon generic substitution are due to differences between formulations or to intrasubject pharmacokinetic variability of the active substance. METHODS:The study was designed as a retrospective reanalysis of existing studies. Nine replicate design bioequivalence studies representing six drug classes - i.e. for alendronate, atorvastatin, cyclosporin, ebastine, exemestane, mycophenolate mofetil, and ropinirole - were retrieved from the Dutch Medicines Regulatory Authority. RESULTS:In most studies, the intrasubject variability in total and peak drug exposure was comparable for the brand-name [in the range 0.01-0.24 for area under the concentration-time curve (AUCt ) and 0.02-0.29 for peak plasma concentration (Cmax ) on a log scale] and generic (0.01-0.23 for AUCt and 0.08-0.33 for Cmax ) drugs, and was comparable with the intrasubject variability upon switching between those drugs (0.01-0.23 for AUCt and 0.06-0.33 for Cmax ). The variance related to subject-by-formulation interaction could be considered negligible (-0.069 to 0.047 for AUCt and -0.091 to 0.02 for Cmax ). CONCLUSION:In the investigated studies, the variation in total and peak exposure seen when a patient is switched from a brand-name to a generic drug is comparable with that seen following repeated administration of the brand-name drug in the patient. Only the intrasubject variability seems to play a crucial and decisive role in the variation in drug exposure seen; no additional formulation-dependent variation in exposure is observed upon switching. Thus, our data support that, for the medicines that were included in the present investigation, from a clinical pharmacological perspective, the benefit-risk balance of a generic drug is comparable with that of the brand-name drug.

SUBMITTER: Yu Y

PROVIDER: S-EPMC4799932 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

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A comparison of the intrasubject variation in drug exposure between generic and brand-name drugs: a retrospective analysis of replicate design trials.

Yu Yang Y Teerenstra Steven S Neef Cees C Burger David D Maliepaard Marc M

British journal of clinical pharmacology 20160115 4

<h4>Aims</h4>The aim of the present study was to investigate whether differences in total and peak drug exposure upon generic substitution are due to differences between formulations or to intrasubject pharmacokinetic variability of the active substance.<h4>Methods</h4>The study was designed as a retrospective reanalysis of existing studies. Nine replicate design bioequivalence studies representing six drug classes - i.e. for alendronate, atorvastatin, cyclosporin, ebastine, exemestane, mycophen ...[more]

PMID: 26574160

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Project description:This meta-analysis aimed to compare the efficacy and adverse events, either serious or mild/moderate, of all generic versus brand-name cardiovascular medicines. We searched randomized trials in MEDLINE, Scopus, EMBASE, Cochrane Controlled Clinical Trial Register, and ClinicalTrials.gov (last update December 1, 2014). Attempts were made to contact the investigators of all potentially eligible trials. Two investigators independently extracted and analyzed soft (including systolic blood pressure, LDL cholesterol, and others) and hard efficacy outcomes (including major cardiovascular adverse events and death), minor/moderate and serious adverse events. We included 74 randomized trials; 53 reported ≥1 efficacy outcome (overall sample 3051), 32 measured mild/moderate adverse events (n = 2407), and 51 evaluated serious adverse events (n = 2892). We included trials assessing ACE inhibitors (n = 12), anticoagulants (n = 5), antiplatelet agents (n = 17), beta-blockers (n = 11), calcium channel blockers (n = 7); diuretics (n = 13); statins (n = 6); and others (n = 3). For both soft and hard efficacy outcomes, 100 % of the trials showed non-significant differences between generic and brand-name drugs. The aggregate effect size was 0.01 (95 % CI -0.05; 0.08) for soft outcomes; -0.06 (-0.71; 0.59) for hard outcomes. All but two trials showed non-significant differences in mild/moderate adverse events, and aggregate effect size was 0.07 (-0.06; 0.20). Comparable results were observed for each drug class and in each stratified meta-analysis. Overall, 8 serious possibly drug-related adverse events were reported: 5/2074 subjects on generics; 3/2076 subjects on brand-name drugs (OR 1.69; 95 % CI 0.40-7.20). This meta-analysis strengthens the evidence for clinical equivalence between brand-name and generic cardiovascular drugs. Physicians could be reassured about prescribing generic cardiovascular drugs, and health care organization about endorsing their wider use.

Project description:ImportanceIn response to scrutiny over high drug prices, manufacturers of insulin and direct-acting antiviral agents for treating hepatitis C have recently introduced authorized generic alternatives to their patented brand-name products. These authorized generic drugs have list prices at least 50% lower than the list price of the brand-name drugs, which should result in savings to patients. However, it is unclear whether these authorized generic drugs are offered on Medicare Part D formularies because they may not provide savings to plans or Medicare.ObjectiveTo assess Medicare Part D formulary coverage for 4 brand-name formulations of insulin and direct-acting antiviral agents and their authorized generic formulations.Design, setting, and participantsThis cross-sectional study used Medicare Prescription Drug Plan Formulary and Pricing Information Files from quarter 3 of 2020 and Medicare Part D plan enrollment for September 2020. Four patented brand-name drugs (sofosbuvir and velpatasvir fixed-dose combination tablets [Epclusa], ledipasvir and sofosbuvir tablets [Harvoni], insulin lispro [Humalog], and insulin aspart [Novolog]) and their authorized generic formulations for all Part D stand-alone prescription drug plans (n = 959) and Medicare Advantage prescription drug plans (n = 3148) were studied.Main outcomes and measuresBeneficiary-weighted formulary coverage of brand-name and authorized generic products; beneficiary out-of-pocket costs; and prerebate plan, manufacturer, and Medicare spending on brand-name and authorized generic products.ResultsIn quarter 3 of 2020, 97% of beneficiaries were in plans that covered brand-name drugs only or both brand-name and authorized generic drugs; approximately 3% were in plans that covered authorized generic drugs only. Observed authorized generic drug list prices were 67%, 62%, and 50% lower than list prices for Epclusa, Harvoni, and each brand-name insulin product, respectively. Medicare beneficiaries using authorized generic drugs could save $270 per year for 12 vials of Humalog and $2974 for a full course of Harvoni. Plans, however, have limited incentives to encourage authorized generic drug use because rebates for brands likely exceed savings available with authorized generic drugs, particularly for beneficiaries with spending that reaches the Medicare Part D coverage gap.Conclusions and relevanceThe results of this cross-sectional study suggest that authorized generic drugs for insulin and direct-acting antiviral agents may lower out-of-pocket spending for patients but are unlikely to provide savings for Part D plans or Medicare. Instead, these drugs allow manufacturers to offer products at a lower list price without materially lowering net prices or profits.

Project description:BackgroundGeneric drugs are bioequivalent to their brand-name counterparts; however, concerns still exist regarding the effectiveness and safety of generic drugs because of small sample sizes and short follow-up time in most studies. The purpose of this study was to evaluate the long-term antihypertensive efficacy, cost-effectiveness and cardiovascular outcomes of generic drugs compared with brand-name drugs.MethodsIn a multicenter, community-based study including 7955 hypertensive patients who were prospectively followed up for an average of 2.5 years, we used the propensity-score-matching method to match the patients using brand-name drugs to those using generic drugs in a ratio of 1:2, 2176 patients using brand-name drugs and 4352 patients using generic drugs.ResultsThere were no significant differences between generic drugs and brand-name drugs in blood pressure (BP)-lowering efficacy, BP control rate, and cardiovascular outcomes including coronary heart disease and stroke. The adjusted mean (95% confidence interval [CI]) of systolic BP (SBP)-lowering was -7.9 mmHg (95% CI, -9.9 to -5.9) in the brand-name drug group and -7.1 mmHg (95% CI, -9.1 to -5.1) in the generic drug group after adjusting for age, sex, body mass index, number of antihypertensive drugs and traditionally cardiovascular risk factors. Among patients aged <60 years, brand-name drugs had a higher BP control rate (47% vs. 41%; P = 0.02) and a greater effect in lowering SBP compared with generic drugs, with the between-group difference of 1.5 mmHg (95% CI, 0.2-2.8; P = 0.03). BP control rate was higher in male patients using brand-name drugs compared with those using generic drugs (46% vs. 40%; P = 0.01). Generic drugs treatment yielded an average annual incremental cost-effectiveness ratio of $315.4 per patient per mmHg decrease in SBP compared with brand-name drugs treatment.ConclusionsOur data suggested that generic drugs are suitable and cost-effective in improving hypertension management and facilitating public health benefits, especially in low- and middle-income areas.

Project description:ImportanceWhether the use of generic vs brand levothyroxine affects thyrotropin levels remains unclear.ObjectiveTo compare the effectiveness of generic vs brand levothyroxine in achieving and maintaining normal thyrotropin levels among new users.Design, setting, and participantsThis retrospective, 1:1 propensity score-matched longitudinal cohort study used the OptumLabs Data Warehouse administrative claims database linked to laboratory results from commercially insured and Medicare Advantage enrollees throughout the United States. Eligible patients were adults (aged ≥18 years) with thyrotropin levels ranging from 4.5 to 19.9 mIU/L who initiated use of generic or brand-name levothyroxine from January 1, 2008, to October 1, 2017. Data were analyzed from August 13, 2018, to October 25, 2019.ExposurePatients received generic or brand-name levothyroxine.Main outcomes and measuresProportion of patients with normal vs markedly abnormal thyrotropin levels (<0.1 or >10 mIU/L) within 3 months and with stable thyrotropin levels within 3 months after the thyrotropin value fell into the normal range.ResultsA total of 17 598 patients were included (69.0% female; 74.0% White; mean [SD] age, 55.1 [16.0] years), of whom 15 299 filled generic and 2299 filled brand-name levothyroxine prescriptions during the study period. Among 4570 propensity score-matched patients (mean [SD] age, 50.3 [13.8] years; 3457 [75.6%] female; 3510 [76.8%] White), the proportion with normal thyrotropin levels within 3 months of filling levothyroxine prescriptions was similar for patients who received generic vs brand-name levothyroxine (1722 [75.4%; 95% CI, 71.9%-79.0%] vs 1757 [76.9%; 95% CI, 73.4%-80.6%]; P = .23), as was the proportion with markedly abnormal levels (94 [4.1%; 95% CI, 3.4%-5.0%] vs 88 [3.9%; 95% CI, 3.1%-4.7%]; P = .65). Among 1034 propensity score-matched patients who achieved a normal thyrotropin value within 3 months of initiation of levothyroxine, the proportion maintaining subsequent normal thyrotropin levels during the next 3 months was similar for patients receiving generic vs brand-name levothyroxine (427 [82.6%] vs 433 [83.8%]; P = .62).Conclusions and relevanceInitiation of generic vs brand-name levothyroxine formulations was associated with similar rates of normal and stable thyrotropin levels. These results suggest that generic levothyroxine as initial therapy for mild thyroid dysfunction is as effective as brand-name levothyroxine.

Project description:ImportanceThe Inflation Reduction Act of 2022 authorizes Medicare to negotiate prices of top-selling drugs based on several factors, including therapeutic benefit compared with existing treatment options.ObjectiveTo determine the added therapeutic benefit of the 50 top-selling brand-name drugs in Medicare in 2020, as assessed by health technology assessment (HTA) organizations in Canada, France, and Germany.Design, setting, and participantsIn this cross-sectional study, publicly available therapeutic benefit ratings, US Food and Drug Administration documents, and the Medicare Part B and Part D prescription drug spending dashboards were used to determine the 50 top-selling single-source drugs used in Medicare in 2020 and to assess their added therapeutic benefit ratings through 2021.Main outcomes and measuresRatings from HTA bodies in Canada, France, and Germany were categorized as high (moderate or greater) or low (minor or no) added benefit. Each drug was rated based on its most favorable rating across countries, indications, subpopulations, and dosage forms. We compared the use and prerebate and postrebate (ie, net) Medicare spending between drugs with high vs low added benefit.ResultsForty-nine drugs (98%) received an HTA rating by at least 1 country; 22 of 36 drugs (61%) received a low added benefit rating in Canada, 34 of 47 in France (72%), and 17 of 29 in Germany (59%). Across countries, 27 drugs (55%) had a low added therapeutic rating, accounting for $19.3 billion in annual estimated net spending, or 35% of Medicare net spending on the 50 top-selling single-source drugs and 11% of total Medicare net prescription drug spending in 2020. Compared with those with high added benefit, drugs with a low added therapeutic rating were used by more Medicare beneficiaries (median 387 149 vs 44 869) and had lower net spending per beneficiary (median $992 vs $32 287).Conclusions and relevanceMany top-selling Medicare drugs received low added benefit ratings by the national HTA organizations of Canada, France, and Germany. When negotiating prices for these drugs, Medicare should ensure they are not priced higher than reasonable therapeutic alternatives.

Dataset Information

A comparison of the intrasubject variation in drug exposure between generic and brand-name drugs: a retrospective analysis of replicate design trials.

Publications

A comparison of the intrasubject variation in drug exposure between generic and brand-name drugs: a retrospective analysis of replicate design trials.

Similar Datasets

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