The budget impact of brodalumab for the treatment of moderate-to-severe plaque psoriasis on US commercial health plans

Abstract

Introduction: Brodalumab is a new biologic approved by the US Food and Drug Administration in 2017 for the treatment of moderate-severe psoriasis. This study evaluated the impact of the introduction of brodalumab on the pharmacy budget on US commercial health plans.

Methods: An Excel-based health economic decision analytic model with a US health plan perspective was developed. The model incorporated published moderate-to-severe psoriasis prevalence data; market shares of common biologic drugs, including adalimumab, ustekinumab, secukinumab, ixekizumab, and etanercept, used for the treatment of moderate–severe psoriasis; 2017-year Wholesale Acquisition Costs for the biologic drugs; drug dispensing fee; patient co-pay; and drug contracting discount. Total annual health plan costs for the biologic drugs were estimated. Scenarios with different proportions of patients treated with brodalumab were compared to a control scenario when no brodalumab was used.

Results: In a hypothetical commercial health plan covering two million members, 7,038 moderate-to-severe psoriasis patients were estimated to be eligible for treatment with brodalumab. Prior to brodalumab approval, the proportions of patients treated by other biologics were estimated at 50.8% for adalimumab, 13.5% for ustekinumab, 14.1% for secukinumab, 4.4% for ixekizumab, and 17.2% for etanercept. With a 20% drug price discount applied to all biologics, the annual health plan costs for brodalumab, adalimumab, ustekinumab, secukinumab, ixekizumab, and etanercept were estimated at $37,224, $49,166, $55,084, $56,061, $64,396, and $57,170, respectively. When no brodalumab is used, the total annual pharmacy budget for the biologics used among these patients was estimated at $414,362,647. Among scenarios where the proportions of brodalumab usage were 3%, 8%, 16%, and 30%, the total annual pharmacy cost was estimated to be reduced by $3,698,129, $9,861,677, $19,723,355, and $36,981,290, respectively.

Conclusion: Based on the economic model, brodalumab has the potential to substantially reduce pharmacy expenditures for the treatment of patients with moderate-to-severe plaque psoriasis in the US.

Keywords:

• Biologic drugs
• brodalumab
• cost-analysis
• moderate-to-severe plaque psoriasis

Introduction

Psoriasis is a chronic systemic inflammatory disease that primarily affects the skin, but is also associated with several significant comorbidities, including psoriatic arthritis, cardiovascular disease, diabetes, inflammatory bowel disease, cancer, and depression¹. Of the 7.5 million individuals in the US estimated to have psoriasis, ∼ 20% have moderate-to-severe disease, and the remaining mild disease^2,3. According to a systematic review of 22 studies, in the US in 2013 the total direct and indirect costs of psoriasis were estimated to range from $51.7 billion to $63.2 billion and $23.9 billion to 35.4 billion, respectively⁴.

In recent years, multiple targeted biologic drugs have been approved by the US Food and Drug Administration (FDA) for the treatment of moderate-to-severe psoriasis. The findings of a meta-analysis of 38 randomized, double-blind, placebo-controlled clinical trials showed that biologics in general are highly efficacious for the treatment of moderate-to-severe psoriasis⁵. However, the newer anti-IL-17 biologics, brodalumab, secukinumab, and ixekizumab, had equivalent or better skin improvement responses compared to other biologics⁵. When taking into consideration the brodalumab efficacy data for achieving a Psoriasis Area and Severity Index (PASI) of 75%, 90%, and 100% and safety data⁵, a preliminary analysis has shown brodalumab was more cost-effective than several other commonly used biologic drugs⁶. For health plan pharmacy benefit administrators, the potential impact of the newer biologic drug brodalumab on pharmacy cost can also be important. We, therefore, evaluated the impact of the introduction of brodalumab on the pharmacy budget of US commercial health plans under different scenarios of the proportions of patients with moderate-to-severe plaque psoriasis treated with brodalumab.

Methods

Economic model

An Excel-based health economic decision analytic model was developed to evaluate the potential cost impact of the introduction of brodalumab (Siliq, Ortho Dermatologics, Bridgewater, NJ) for the treatment of moderate-to-severe plaque psoriasis to the pharmacy budget of US commercial health plans. The prevalence of moderate-to-severe plaque psoriasis was based on published literature^3,7, and used to estimate the number of moderate-to-severe psoriasis patients eligible for brodalumab treatment in a commercial health plan with a hypothetical 2 million covered members. The findings from the model are proportionally scalable to health plans with larger or smaller number of covered lives. The market shares of common biologic drugs used for the treatment of moderate-to-severe psoriasis, including adalimumab (Humira, Abbvie, North Chicago, IL), ustekinumab (Stelara, Janssen Biotech, Titusville, NJ), secukinumab (Cosentyx, Novartis Pharma, East Hanover, NJ), ixekizumab (Taltz, Eli Lilly, Indianapolis, IN), and etanercept (Enbrel, Amgen, Thousand Oaks, CA), were based on the current US market share data⁸. The drugs evaluated in the economic model were selected to reflect the most commonly used biologic drugs for the treatment of moderate-to-severe plaque psoriasis. The 2017-year Wholesale Acquisition Cost (WAC) of these biologic drugs and brodalumab were obtained from RedBook⁹. Drug dispensing fee¹⁰, patient co-pay¹⁰, and drug contracting discount (a hypothetical estimate of 20%) were also incorporated into the model.

Estimate of impact of the introduction of brodalumab on the pharmacy budget of US commercial health plans

Total annual health plan costs for the six different biologic drugs were estimated using the economic model. Next, total annual health plan costs were estimated for scenarios with different proportions (3%, 8%, 16%, and 30%) of patients with moderate-to-severe plaque psoriasis treated with brodalumab and compared to a control scenario when no brodalumab was used. These hypothetically derived proportions of patients with brodalumab usage were proportionally drawn from the market shares of the other evaluated biologic drugs⁸.

Results

Estimate of number of patients with moderate-to-severe plaque psoriasis in a US health plan

Of a hypothetical US health plan with 2 million members, 46,000 (2.3%)⁷ were estimated to have psoriasis, with 39,100 having plaque psoriasis³; 7,820 (20%)³ were predicted to have moderate-to-severe disease and to be eligible for treatment with brodalumab.

Market shares of biologic drugs prior to brodalumab approval

Prior to brodalumab FDA approval, the proportions of patients treated by the other biologic drugs were estimated at 50.8% for adalimumab, 13.5% for ustekinumab, 14.1% for secukinumab, 4.4% for ixekizumab, and 17.2% for etanercept⁸.

Estimate of total annual biologic drug costs and impact of increasing brodalumab usage on the pharmacy budget of US health plans

With a hypothetical 20% discount applied to all biologic drug WAC prices, the annual health plan costs for brodalumab, adalimumab, ustekinumab, secukinumab, ixekizumab, and etanercept were estimated at $37,224, $49,166, $55,084, $56,061, $64,396, and $57,170, respectively (Table 1). When no brodalumab is used and taking into account the estimated other biologic drug market shares, the total annual pharmacy budget for the biologic drugs used among patients with moderate-to-severe plaque psoriasis was estimated at $414,362,647 (Table 2). Among scenarios where the proportions of brodalumab usage were 3%, 8%, 16%, and 30%, the total annual pharmacy cost was estimated to be reduced by $3,698,129, $9,861,677, $19,723,355, and $36,981,290, respectively (Figure 1).

Figure 1. Total annual health plan pharmacy cost difference to treat patients with moderate-to-severe plaque psoriasis with increasing proportions of patients with brodalumab usage.

Table 1. Total annual biologic drug cost for US commercial health plans.

	Brodalumab	Adalimumab	Ustekinumab	Secukinumab	Ixekizumab	Etanercept
Drug dispensing fee per Rx^10	$3	$3	$3	$3	$3	$3
Average patient co-pay per Rx^10	$51	$51	$51	$51	$51	$51
Drug cost without discount per patient-year	$47,250	$62,177	$69,155	$70,796	$81,215	$72,182
Hypothetical drug discount	20%	20%	20%	20%	20%	20%
Drug cost after discount per patient-year	$37,800	$49,742	$55,324	$56,637	$64,972	$57,746
Total patient co-pay per patient-year	$612	$612	$255	$612	$612	$612
Total annual biologic drug cost to commercial health plan pharmacy	$37,224	$49,166	$55,084	$56,061	$64,396	$57,170

Rx: Prescription.

Table 2. Total annual health plan pharmacy cost for biologic drugs used to treat patients with moderate-to-severe plaque psoriasis with increasing proportions of patients with brodalumab usage.

Proportions of patients with brodalumab usage	0%	3%	8%	16%	30%
Number of patients treated with biologic drugs
Adalimumab	3,973	3,854	3,655	3,337	2,781
Ustekinumab	1,053	1,021	969	884	737
Secukinumab	1,105	1,071	1,016	928	773
Ixekizumab	348	337	320	292	244
Etanercept	1,342	1,302	1,234	1,127	939
Brodalumab	0	235	626	1,251	2,346
Total Patients	7,820	7,820	7,820	7,820	7,820
Total health plan pharmacy payment for biologic drugs
Adalimumab	$195,324,564	$189,464,827	$179,698,599	$164,072,634	$136,727,195
Ustekinumab	$58,001,365	$56,261,324	$53,361,256	$48,721,147	$40,600,956
Secukinumab	$61,925,101	$60,067,348	$56,971,093	$52,017,085	$43,347,571
Ixekizumab	$22,402,169	$21,730,104	$20,609,995	$18,817,822	$15,681,518
Etanercept	$76,709,448	$74,408,165	$70,572,692	$64,435,936	$53,696,614
Brodalumab	$0	$8,732,750	$23,287,334	$46,574,669	$87,327,504
Total annual biologic drug cost to commercial pharmacy health plan	$414,362,647	$410,664,518	$404,500,969	$394,639,292	$377,381,357

Discussion

Among the evaluated commonly used biologics drugs for psoriasis treatment on the US market, brodalumab had the lowest annual WAC drug price. Based on this economic model, when the usage of brodalumab was hypothetically increased among patients with moderate-to-severe plaque psoriasis, the pharmacy costs to US health plans were estimated to be substantially reduced. The current model did not include the recently approved biologic drug, guselkumab, for the treatment of moderate-to-severe plaque psoriasis. However, since guselkumab is priced at $9,684 (WAC price, RedBook⁹) for each injection, it is expected that the pharmacy cost of guselkumab will be substantially higher than that of brodalumab. Furthermore, other biologic drug types (e.g., biosimilars) were not evaluated in the model, since substitution practices by providers in the real-world settings are not currently well understood. As psoriasis is a chronic disease and patients with moderate-to-severe disease are commonly treated for a long period of time, the cost of such long-term treatment is important for consideration by health plans and other stakeholders. Economic models that incorporate usage patterns of other drugs and drug types (e.g., substitution of biosimilars) may be needed to update the current economic model in future studies.

Treatment of moderate-to-severe psoriasis patients with biologic drugs is efficacious to improve skin symptoms, increase overall health status, and improve quality-of-life^5,11,12. Furthermore, treatment with many of the different biologic drugs has been shown to be cost-effective in the US, with some showing better cost-effectiveness than others^10,11,13. However, many studies of psoriasis patients have reported persistent moderate-to-severe disease, despite treatment with some biologic drugs and high treatment dissatisfaction rates, indicating that there is a significant unmet need for better management of this chronic illness^14–18. Cost of biologic drugs and inconsistent insurance coverage are also common components of patient dissatisfaction^15,18. It will be important for future studies to examine the real-world efficacy and safety of brodalumab, and its impact on patient quality-of-life and adherence and satisfaction with treatment. When these data become available, it will be necessary to also incorporate such information into future economic modeling studies.

Brodalumab is highly efficacious for the treatment of patients with moderate-to-severe psoriasis^19,20, and based on a meta-analysis of clinical trial data, is associated with better skin improvement than some other biologic drugs⁵. While the current model only assessed the impact of the drug costs to the pharmacy budget of health plans, it is still valuable to the health plan and other stakeholders as it provides a complementary view to the previous cost-effective analysis⁶ of how drugs may impact the different aspects of healthcare economic landscapes. Our current cost analysis predicts that brodalumab will be a less costly alternative, predominately because of its lower WAC price, for the treatment of moderate-to-severe psoriasis for the pharmacy budget of US commercial health plans.

Limitations

The drugs evaluated in this economic model were selected to reflect the most commonly used for the treatment of moderate-to-severe plaque psoriasis. The model did not include all drugs currently utilized for the treatment of moderate-to-severe plaque psoriasis in the US, such as infliximab, since it can be administered intravenously and may be covered by the medical benefits of health insurances, while our current economic model focused on the evaluation of costs of drugs covered by pharmacy benefits. Also, the extra costs for multiple loading dosages required for some of the biologic drugs, such as secukinumab and ixekizumab, were not incorporated into the model, and the costs of these drugs may be higher or lower than estimated, depending on the switching frequency and drug treatment duration of such drugs in the real-world settings. Study of commonly used drug dosage patterns of the newer biologic drugs to treat plaque psoriasis in the real-world setting may be warranted in future studies. Additionally, we used a hypothetical 20% drug discount for all of the evaluated biologic drugs, and this discount, as well as other offered rebates, may differ in individual health plans. As this rebate information is often proprietary, exact drug discounts could not be incorporated into this model. However, this 20% discount is a commonly used assumption in other similar economic models²¹. The results of this economic analysis are reflective of biologic drug costs to US commercial payers and may not generalize to other health plan types, such as Medicare or Medicaid. For this model, we used a 1-year time horizon of maintenance biologic drug usage (annual health plan cost), which is typical for pharmacy budget planning. This model only assessed the impact of drug costs on the pharmacy budget for the treatment of moderate-to-severe plaque psoriasis. Some biologics may have more than one indication beyond the treatment of moderate-to-severe plaque psoriasis, and drug cost contracting discounts may be instituted across multiple indications, and this scenario was not evaluated in this model. However, given that this model indicated brodalumab is the least costly biologic for the treatment of moderate-to-severe plaque psoriasis, the inclusion of brodalumab to a health plan drug formulary may help reduce the total pharmacy cost for a health plan, even when there is no change on the formulary positions of other biologics.

Conclusions

Based on the economic model, brodalumab has the potential to substantially reduce pharmacy expenditures for the treatment of patients with moderate-to-severe plaque psoriasis in the US. The predicted impact of brodalumab on the US pharmacy budget of commercial health plans may be helpful for healthcare providers, payers, and patients for making decisions on treatment plans.

Transparency

Declaration of funding

This research was supported by Ortho Dermatologics.

Declaration of financial/other relationships

JJW is an investigator for AbbVie, Amgen, Eli Lilly, Janssen, Novartis, and Regeneron. SRF served as a consultant for Ortho Dermatologics for conducting this study. SR is an employee of Ortho Dermatologics. BM, MLS, and JL are employees of Novosys Health, which has received research funds from Ortho Dermatologics for conducting this study and development of this manuscript. Peer reviewers on this manuscript have received an honorarium from JME for their review work. A peer reviewer on this manuscript has declared serving as a consultant for Janssen, Novartis, and Abbvie, as well as an investigator for Amgen, Abbvie, Eli Lilly, Pfizer, Celgene, Valeant, Janssen, and Novartis. The remaining peer reviewers have no relevant financial relationships to disclose.