Generic substitution of antiepileptic drugs: What's a clinician to do?

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.

Influencers of generic drug utilization: A systematic review

INTRODUCTION

With an increase in prescription drug spending and rising drug costs there is a need to encourage the use of generic prescription drugs. However, maximizing generic drug use is not possible without the public's positive perception and meeting their informational needs about generic drugs. Thus, improving the public's confidence in, and knowledge of generic drugs on the market is critical. The objective of this systematic review is to examine and evaluate the studies focusing on the nature and extent of key factors influencing generic drug use in the United States in order to help guide policy, education and practice interventions.

MATERIALS AND METHODS

Using multiple search engines and key word screening criteria, empirical studies published in English between January 1, 2005 and December 31, 2015 were identified. A qualitative synthesis of the evidence identified domains of key factors that influenced generic drug use across studies.

RESULTS

Over 3000 citations met the key word screening criteria; 67 of these met inclusion criteria for the systematic review. Seven domains of factors that influence generic drug utilization were identified: 1) patient-related factors, 2) formulary management or cost containment, 3) healthcare policies, 4) promotional activities, 5) educational initiatives, 6) technology, and 7) physician-related factors.

CONCLUSION

Patients, physicians, pharmacists, formulary managers, and policymakers play an important role in generic drug use. Understanding the factors influencing generic drug use can help guide future policy, education, and practice interventions to increase generic drug use.

Biosimilars in rheumatic diseases: structural and functional variability that may impact clinical and regulatory decisions

Biologics as therapeutic interventions for human disease represent both a distinctly modern novelty and an echo of ancient, or at least old, medical practice. The similarity lies in the sense that in both the synthetic effort occurs in living organisms (an extract of a plant, animal tissue, or a cell culture) while the difference is apparent in the bioengineering required in modern methods and the corresponding flexibility to customize the therapeutic product. Although the concept of looking to living systems as a source of medically useful compounds either for research or for actual patient care has never vanished, the development of biochemistry and advances in medicinal chemistry made production by total synthesis the standard for a safe, reliable, and commercial drug production at sufficient scale. In this interval was where much of the modern apparatus for approving medical therapies came to be developed, and as such, the most proper extension of the regulatory regime to modern biologics is not entirely obvious. In particular, the notion of generics for off-patent conventional pharmaceuticals and their role in the marketplace with respect to increasing the accessibility of treatment is not congruent with the relationship between what are known as biosimilars and off-patent originating biologics. In this article, we review elements of the scientific basis for challenges in the production, use, and regulation of biosimilars. In light of these advances, we propose suggestions to modify constraints on biosimilar regulations in the interest of patient care and access to therapies.

Medicare Part D payments for neurologist-prescribed drugs

OBJECTIVE

To describe neurologists' Medicare Part D prescribing patterns and the potential effect of generic substitutions and price negotiation, which is currently prohibited.

METHODS

The 2013 Medicare Part D Prescriber Public Use and Summary files were used. Payments for medications were aggregated by provider and drug (brand or generic). Payment, proportion of generic claims or day's supply, and median payment per monthly supply of medication were calculated by physician specialty and drug. Savings from generic substitution were estimated for brand drugs with a generic available. Medicare prices were compared to drug prices negotiated by the federal government with pharmaceutical manufacturers for the Veterans Administration (VA).

RESULTS

Neurologists comprised 13,060 (1.2%) providers with $5.0 billion (4.8%) in total payments, third highest of all specialties, with a median monthly payment of $141 (interquartile range $85-225). Multiple sclerosis drugs had the highest payments ($1.8 billion). Within neurologic disease groups ($3.4 billion in payments), 54.2%-91.8% of monthly supplies were generic, but 11.9%-71.3% of the payment was for generic medications. Generic substitution resulted in a $269 million (6.5%) payment decrease. VA pricing resulted in $1.5 billion (44.5% of $3.4 billion) in savings.

CONCLUSIONS

High payment per monthly supply of medication underlies the high total neurology drug payments and is driven by multiple sclerosis drugs. Lowering drug expenditures by Medicare should focus on drug prices.

Intrapatient variation in antiepileptic drug plasma concentration after generic substitution vs stable brand-name drug regimens

Generic substitution of antiepileptic drugs (AEDs) is still a matter of controversy and concern among clinicians and patients. We aimed to assess intrasubject variation in plasma concentrations of lamotrigine (LTG), levetiracetam (LEV) and topiramate (TPM) after generic substitution compared with a stable brand-name drug regimen in a population of patients with epilepsy. A retrospective analysis was performed on prospectively collected and stored data from our therapeutic drug monitoring (TDM) database for the years 2009-2014. The main outcome variable was the proportion of patients who, after switching from branded to generic formulations, showed a greater than ±20% change in AED plasma concentrations compared to the proportion of control patients showing a change in AED plasma concentrations of the same extent while receiving stable branded formulations over repeated TDM tests. Fifty patients on LTG, 27 on LEV and 16 on TPM showing at least one TDM test while receiving generic products fulfilled the inclusion/exclusion criteria for the analysis and were compared with 200 control patients for LTG, 120 for LEV and 80 for TPM. The proportion of patients showing an intrasubject change greater than ±20% in AED plasma concentrations was similar in the brand name vs generic group compared with the control one for LTG (22% vs 33%) and LEV (44% vs 38%), while it was higher in the control group for TPM (41% vs 6%, p<0.01). These are the first data in the literature about the within-patient variation in steady-state plasma concentrations of a series of stable treatments with brand-name AEDs in a real clinical setting. In conclusion, a significant interday variability in intrapatient LTG, LEV and TPM plasma concentrations can be observed even in patients stabilized with the same brand name product over time. This suggests that any change in plasma AED concentration and possible related clinical effects after generic substitution may be not necessarily related to the switch. Our results should be confirmed by large, prospective, blinded, randomized controlled studies in people with epilepsy.