Orphan therapies: making best use of postmarket data

Budgetary Impact of Medicinal Therapies for Rare Diseases in Bulgaria

BACKGROUND

Rare diseases have been continually outlined as one of the causes for the National Health Insurance Fund's (NHIF) deficit spending in Bulgaria.

AIM

To estimate the budgetary impact of rare disease medicinal therapies from NHIF perspective for 2014 and 2016.

MATERIALS AND METHODS

Budgetary impact of rare diseases is calculated as a percentage of NHIF total pharmaceutical spending. Total expenditure per ICD-10 code, mean annual number of patients reimbursed and mean annual cost per patient are analysed.

RESULTS

Budgetary impact of rare diseases reached a plateau of about 9% of NHIF total pharmaceutical spending for 2014-2016. Mean number of patients reimbursed and mean annual cost per patient increased by median rates of 4.27% and 2.54%, respectively. Glycogen storage disease, neuropathic heredofamilial amyloidosis and C1 esterase inhibitor deficiency stood out, as they had the second, fourth and fifth most expensive medicinal treatment cost. While accounting for only 92 patients in 2016, these three conditions contributed for 22.89% of NHIF total expenditure on rare disease medicinal therapies. For comparison, coagulation defects, with the biggest total cost per indication, had a similar budgetary impact - 24.88%, but for 277 patients reimbursed.

CONCLUSIONS

Our study does not support the concerns about uncontrolled growth of expenditures for rare disease medicinal therapies. Nevertheless, there is a need for enhanced post-marketing surveillance and performance-based payment of these treatments. Development, collection and analysis of local real-world data have been increasingly applied as a tool to advance these health policy goals.

Generic Substitution of Orphan Drugs for the Treatment of Rare Diseases: Exploring the Potential Challenges

Generic drugs are important components of measures introduced by healthcare regulatory authorities to reduce treatment costs. In most patients and conditions the switch from a branded drug to its generic counterpart is performed with no major complications. However, evidence from complex diseases suggests that generic substitution requires careful evaluation in some settings and that current bioequivalence criteria may not always be adequate for establishing the interchangeability of branded and generic products. Rare diseases, also called orphan diseases, are a group of heterogeneous diseases that share important characteristics: in addition to their scarcity, most are severe, chronic, highly debilitating, and often present in early childhood. Finding a treatment for a rare disease is challenging. Thanks to incentives that encourage research and development programs in rare diseases, several orphan drugs are currently available. The elevated cost of orphan drugs is a highly debated issue and a cause of limited access to treatment for many patients. As patent protection and the exclusivity period of several orphan drugs will expire soon, generic versions of orphan drugs should reach the market shortly, with great expectations about their impact on the economic burden of rare diseases. However, consistent with other complex diseases, generic substitution may require thoughtful considerations and may be even contraindicated in some rare conditions. This article provides an overview of rare disease characteristics, reviews reports of problematic generic substitution, and discusses why generic substitution of orphan drugs may be challenging and should be undertaken carefully in rare disease patients.

Using a meta-narrative literature review and focus groups with key stakeholders to identify perceived challenges and solutions for generating robust evidence on the effectiveness of treatments for rare diseases

INTRODUCTION

For many rare diseases, strong analytic study designs for evaluating the efficacy and effectiveness of interventions are challenging to implement because of small, geographically dispersed patient populations and underlying clinical heterogeneity. The objective of this study was to integrate perspectives from published literature and key rare disease stakeholders to better understand the perceived challenges and proposed methodological approaches to research on clinical interventions for rare diseases.

METHODS

We used a meta-narrative literature review and focus group interviews with key rare disease stakeholders to better understand the perceived challenges in generating and synthesizing treatment effectiveness evidence, and to describe various research methods for mitigating these identified challenges. Data from both components of this study were synthesized narratively according to research paradigms that emerged from our data.

RESULTS

Results from our meta-narrative literature review and focus group interviews revealed three fundamental challenges in generating robust treatment effectiveness evidence for rare diseases: i) limitations in recruiting a sufficient sample size to achieve planned statistical power; ii) inability to account for clinical heterogeneity and assess treatment effects across a clinical spectrum; and iii) reliance on short-term, surrogate outcomes whose clinical relevance is often unclear. We mapped these challenges and associated solutions to three interrelated research paradigms: i) explanatory evidence generation; ii) comparative effectiveness/pragmatic evidence generation; and iii) patient-oriented evidence generation. Within each research paradigm, numerous criticisms and potential solutions have been described with respect to overcoming these challenges from a research study design perspective.

CONCLUSIONS

Over time, discussions about clinical research for interventions for rare diseases have moved beyond methodological approaches to overcome challenges related to explanatory evidence generation, with increased recognition of the importance of pragmatic and patient-oriented evidence. Future directions for our work include developing a framework to expand current evidence synthesis practices to take into consideration many of the concepts discussed in this paper.