Miami Beach—During a 10-year period, the average direct costs per patient with moderate-to-severe psoriasis who took biologics were nearly $200,000 regardless of the drug they were prescribed, while productivity losses averaged around $200,000 per patient.
Results were presented during a poster session at the ACC meeting. The poster was titled Long-Term Costs of Biologics in the Treatment of Moderate to Severe Psoriasis in the US.
The authors estimated approximately 1% to 3% of people in the world have psoriasis, a chronic inflammatory systemic disease caused by a dysregulated immune system leading to changes in the resident cells of the skin. To treat psoriasis, patients are typically prescribed retinoids, methotrexate, or cyclosporine. Currently, however, increasing numbers of patients with moderate-to-severe psoriasis are being prescribed biologic agents, although they are more expensive than conventional therapies.
In this study, the authors developed a Markov model with a 10-year time horizon to describe the treatment pathway of patients with moderate-to-severe psoriasis who are eligible for monthly cycles of biologics. In the model, patients took 2 lines of biologics, beginning with adalimumab, etanercept, infliximab, or ustekinumab, which are all approved by the FDA to treat psoriasis. They were then administered best supportive care, defined as treatment with systemic therapy (cyclosporine or methotrexate) or no active treatment, as well as outpatient and inpatient care.
Patients were considered to have responded to treatment if they achieved at least a 75% reduction from baseline on the Psoriasis Area and Severity Index (PASI) score. The authors assumed an annual dropout rate of 20% during the trial period. After the trial period, they assumed a continuation of treatment until patients dropped out. In addition, patients who discontinued treatment or did not respond to treatment were assumed to take other lines of treatment, while patients who received best supportive care were assumed to continue in that health state for the rest of their lives.
For the first-line biologic therapies, the average time on the treatment was 3.0 years for adalimumab, 2.2 years for etanercept, 3.3 years for infliximab, and 2.8 years for ustekinumab. The authors estimated the 10-year direct costs per patient were $176,535 with adalimumab as first-line therapy, $177,172 with etanercept, $179,311 with infliximab, and $181,861 with ustekinumab. The estimated per patient productivity losses over 10 years were $18,755 for adalimumab, $20,592 for etanercept, $17,945 for infliximab, and $19,139 for ustekinumab.
Drug costs accounted for 59.0% in the adalimumab group, 55.7% in the etanercept group, 60.4% in the infliximab group, and 59.1% in the ustekinumab group. Hospitalization costs when receiving biologic agents accounted for 0.2% of costs in each group, while productivity loss costs accounted for 9.6% in the adalimumab group, 10.4% in the etanercept group, 9.1% in the infliximab group, and 9.5% in the ustekinumab group.
Over 10 years, the estimated per patient cumulative costs for best supportive care ranged between $52,791 and $64,523 with adalimumab as first-line therapy, $57,928 and $70,800 with etanercept, $50,441 and $61,651 with infliximab, and $53,821 and $65,781 with ustekinumab.
The authors cited a few limitations, including that they assumed patients had 2 lines of biologics and then best supportive care because they could not find treatment pathways. Also, due to a lack of information on treatment efficacy, the researchers measured efficacy using PASI response independent of past treatments.
They also based patient monitoring and resource use on expert opinion and resource use estimates for best supportive care on a cost-effectiveness study in the United Kingdom. In addition, they could not find long-term evidence on dropout rates, so they assumed a uniform annual dropout rate of 20% for all treatments.
This study was supported by Celgene Corporation.