Value Assessment and Quantitative Benefit-Risk Modelling of Biosimilar Infliximab for Crohn's Disease

A Systematic Literature Review of Gaps and Challenges in Value Assessment of Biosimilars: An ISPOR Special Interest Group Report

OBJECTIVES

This study aims to provide an overview of the gaps and challenges in the value assessment of biosimilars and to identify potential approaches to address them.

METHODS

A multidisciplinary, international team of biosimilar experts identified gaps and challenges. A systematic review was conducted of the peer-reviewed literature in PubMed, EMBASE, Web of Science Core Collection, EBSCOhost Business Source Complete; and of the gray literature. Preliminary results were presented at ISPOR conferences and this article benefited from 2 review rounds among ISPOR Biosimilar Special Interest Group members.

RESULTS

Given that a biosimilar is highly similar to its reference biologic, health technology assessment agencies should accept the comparability exercise approved by regulatory authorities and, thus, conduct a price comparison when biosimilar reimbursement is requested for the same indication as the reference biologic. If the reference biologic is not reimbursed or is not the standard of care, a full economic evaluation of the biosimilar versus a relevant comparator needs to be conducted. To date, little consideration has been given to specific challenges, such as how biosimilar value assessment can account for the nocebo effect, potential differences between biologic-naive and biologic-experienced patients, the availability of intravenous and subcutaneous administration forms or different administration devices for the same active compound, value-added services, and the contribution of biosimilars for generating health gain at the population level.

CONCLUSIONS

There is a need to gather further insights in the methodology of value assessment for biosimilars, and health technology assessment agencies need to develop more elaborate guidance on biosimilar value assessment in specific circumstances.

Infliximab Pricing in International Economic Evaluations in Inflammatory Bowel Disease to Inform Biologic and Biosimilar Access Policies: A Systematic Review

Background. Policies mandating the use of lower cost biosimilars in patients with inflammatory bowel disease (IBD) have created concerns for patients who prefer their original biologic. Purpose. To inform the cost-effectiveness of biosimilar infliximab treatment in IBD by systematically reviewing the effect of infliximab price variation on cost-effectiveness for jurisdictional decision making. Data Sources. MEDLINE, Embase, Healthstar, Allied and Complementary Medicine, Joanna Briggs Institute EBP Database, International Pharmaceutical Abstracts, Health and Psychosocial Instruments, Mental Measurements Yearbook citation databases, PEDE, CEA registry, HTA agencies. Study Selection. Economic evaluations of infliximab for adult or pediatric Crohn's disease and/or ulcerative colitis published from 1998 through 2019 in which drug price was varied in sensitivity analysis were included. Data Extraction. Study characteristics, main findings, and results of drug price sensitivity analyses were extracted. Studies were critically appraised. The cost-effective price of infliximab was determined based on the stated willingness-to-pay (WTP) thresholds for each jurisdiction. Data Synthesis. Infliximab price was examined in sensitivity analysis in 31 studies. Infliximab showed favorable cost-effectiveness at a price ranging from CAD $66 to $1,260 per vial, depending on jurisdiction. A total of 18 studies (58%) demonstrated cost-effectiveness ratios above the jurisdictional WTP threshold. Limitations. Drug prices were not always reported separately, WTP thresholds varied, and funding sources were not consistently reported. Conclusion. Despite the high cost of infliximab, few economic evaluations examined price variation, limiting the ability to infer the effects of biosimilar introduction. Alternative pricing strategies and access to treatment could be considered to enable IBD patients to maintain access to their current medications.

Highlights

In an effort to reduce public drug expenditures, Canadian and other jurisdictional drug plans have mandated the use of lower cost, but similarly effective, biosimilars in patients with newly diagnosed inflammatory bowel disease or require a nonmedical switch for established patients. This switch has created concerns for patients and clinicians who want to maintain the ability to make treatment decisions and remain with the original biologic.It is customary for economic evaluations to assess the robustness of results to variations in high-cost items such as medications. In the absence of economic evaluations of biosimilars, examining biologic drug price in sensitivity analysis provides insight into the cost-effectiveness of biosimilar alternatives. A total of 31 economic evaluations of infliximab for the treatment of inflammatory bowel disease varied the infliximab price in sensitivity analysis.The infliximab price deemed to be cost-effective within each study ranged from CAD $66 to CAD $1,260 per 100-mg vial. A total of 18 studies (58%) demonstrated an incremental cost-effectiveness ratio above the jurisdictional willingness-to-pay threshold. If policy decisions are based on price, then originator manufacturers could consider reducing the price or negotiating alternative pricing models to enable patients with inflammatory bowel disease to remain on their current medications.

SeHCAT (tauroselcholic [75selenium] acid) for the investigation of bile acid diarrhoea in adults: a systematic review and cost-effectiveness analysis

Background

Tauroselcholic [75selenium] acid (SeHCAT™) (GE Healthcare, Chicago, IL, USA) is a radiopharmaceutical that may be useful in diagnosing bile acid diarrhoea.

Objectives

To assess the clinical effectiveness and cost-effectiveness of SeHCAT for the investigation of adults with chronic unexplained diarrhoea, diarrhoea-predominant irritable bowel syndrome or functional diarrhoea (suspected primary bile acid diarrhoea), and adults with chronic diarrhoea and Crohn’s disease who have not undergone ileal resection (suspected secondary bile acid diarrhoea).

Methods

Sixteen databases were searched to November 2020. The review process included measures to minimise error and bias. Results were summarised by primary or secondary bile acid diarrhoea and study quality was considered. The cost-effectiveness analysis combined a short-term (6-month) decision-analytic model (diagnosis and initial treatment response) and a lifetime Markov model comprising three health states (diarrhoea, no diarrhoea and death), with transitions determined by probabilities of response to treatment. Analyses were conducted from an NHS and Personal Social Services perspective.

Results

Twenty-four studies were included in this review. Of these, 21 were observational studies, reporting some outcome data for patients treated with bile acid sequestrants, and in which only patients with a positive SeHCAT test were offered bile acid sequestrants. The median rate of response to bile acid sequestrants, among patients with a 7-day SeHCAT retention value of ≤ 15%, was 68% (range 38–86%) (eight studies). The estimated sensitivity of SeHCAT (≤ 15% threshold) to predict positive response to colestyramine was 100% (95% confidence interval 54.1% to 100%) and the specificity estimate was 91.2% (95% confidence interval 76.3% to 98.1%) (one study). The median proportion of treated patients who were intolerant/discontinued bile acid sequestrants was 15% (range 4–27%) (eight studies). There was insufficient information to determine whether or not intolerance varied between colestyramine, colestipol and colesevelam. For both populations, the SeHCAT 15% (i.e. a SeHCAT retention value of ≤ 15%) strategy dominated other strategies or resulted in incremental cost-effectiveness ratios of < £20,000–30,000 per quality-adjusted life-year gained. For the suspected primary bile acid diarrhoea population, SeHCAT 15% was the strategy most likely to be cost-effective: 67% and 73% probability at threshold incremental cost-effectiveness ratios of £20,000 and £30,000 per quality-adjusted life-year gained, respectively. For the Crohn’s disease population, these probabilities were 89% and 92% at £20,000 and £30,000 per quality-adjusted life-year gained, respectively. Cost-effectiveness was mostly led by treatment response. SeHCAT 15% was the strategy with the highest response rate in the majority of scenarios explored.

Limitations and conclusions

There is a lack of evidence linking the use of SeHCAT testing to patient-relevant outcomes. The optimal SeHCAT threshold, to define bile acid diarrhoea and select patients for treatment with bile acid sequestrants, is uncertain. It is unclear whether or not patients with ‘borderline’ or ‘equivocal’ 7-day SeHCAT retention values (e.g. between 10% and 15%) and patients with values of > 15% could benefit from treatment with bile acid sequestrants. Although the results of the economic evaluation conducted for both populations indicated that the SeHCAT 15% strategy dominated the other two strategies or resulted in incremental cost-effectiveness ratios that were lower than the common thresholds of £20,000 or £30,000 per quality-adjusted life-year gained, the paucity and poor quality of evidence mean that uncertainty is high.

Future work

The optimum study design would be a multiarm randomised controlled trial, in which participants meeting the inclusion criteria are randomised to receive colestyramine, colestipol, colesevelam or placebo, and all participants receive SeHCAT testing.

Study registration

This study is registered as PROSPERO CRD42020223877.

Funding

This project was funded by the National Institute for Health and Care Research (IHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 26, No. 45. See the NIHR Journals Library website for further project information.

A health economic guide to market access of biosimilars

Introduction: Little is known about market access to biosimilars from a health economic perspective, except for studies that compute the budget impact of biosimilar use. Areas covered: This comprehensive health economic guide to the market access of biosimilars focuses on the role of biosimilars in pharmaceutical innovation and competition, the objective of biopharmaceutical policy, the budget impact of biosimilars, and the cost-effectiveness of biologic therapy in the presence of biosimilars. Expert opinion: We argue that the objective of biopharmaceutical policy in a health system should be to create a competitive and sustainable market for off-patent reference biologics, biosimilars, and next-generation biologics that makes biologic therapy available to patients at the lowest cost. Market access of biosimilars can contribute to this objective as a result of the lower price of biosimilars and price competition with alternative therapies. The resulting improvement in the cost-effectiveness of biologic therapy needs to be accounted for by revisiting reimbursement decisions and conditions. When examining the cost-effectiveness of biologic therapy following patent expiry, stakeholders need to consider residual uncertainties at the time of biosimilar marketing authorization, the nocebo effect, market entry of a second-generation reference biologic with a different administration form than the biosimilar, and value-added services.