Actual per-patient costs of successful study treatment. Averaged wholesale costs of therapy among patients with a 50% improvement in Psoriasis Area and Severity Index (PASI-50) (18 of 27 in the liquor carbonis distillate [LCD] group [67%]; 10 of 28 in the calcipotriol group [36%]) and with PASI-75 (11 of 27 in the LCD group [41%]; 0 of 28 in the calcipotriol group). *P < .05.
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Alora-Palli MB, Brouda I, Green B, Kimball AB. A Cost-effectiveness Comparison of Liquor Carbonis Distillate Solution and Calcipotriol Cream in the Treatment of Moderate Chronic Plaque Psoriasis. Arch Dermatol. 2010;146(8):918–935. doi:10.1001/archdermatol.2010.167
The cost of medications for the treatment of chronic conditions such as psoriasis can be overwhelming to patients and the health care system. Patients with mild to moderate psoriasis are generally offered topical medications, ranging in cost from $0.80/g1 for clobetasol propionate to $7.45/g1 for the betamethasone dipropionate/calcipotriol ointment Taclonex (Leo Pharma A/S, Ballerup, Denmark) as first-line and often second-line therapy.2
A new addition to the psoriasis armamentarium is an over-the-counter (OTC) product, PSORENT Psoriasis Topical Solution (NeoStrata Company Inc, Princeton, New Jersey) that contains 15% liquor carbonis distillate (LCD) solution (2.3% coal tar, US Pharmacopeia) and costs $0.26/g. Liquor carbonis distillate is a well-known, effective,3 and inexpensive ingredient for treating psoriasis, shown to be as beneficial as calcipotriol ointment4,5 and calcipotriol cream6 in previous clinical studies.
Herein, we report the findings of a cost-effectiveness comparison between the new LCD solution and calcipotriol cream during a randomized, active-controlled, investigator-blinded, clinical trial conducted at the Clinical Unit for Research Trials in Skin, Massachusetts General Hospital, Boston, between December 2006 and November 2008.7
The study protocol was approved by Partners Human Research Committee, Boston, and informed consent was obtained from all patients at entry. Patients with moderate chronic plaque psoriasis (3%-15% of body surface area [BSA] affected minus scalp, palms, soles, and groin) were randomized to apply either 15% LCD solution (PSORENT) or calcipotriol, 0.005%, cream (Dovonex Cream; Warner Chilcott Inc, Rockaway, New Jersey) twice daily for 12 weeks.7 Blinded investigators evaluated patients using a modified Psoriasis Area and Severity Index (PASI) from 0 to 64.8 (with the head excluded) at weeks 0 (baseline), 2, 4, 8, 12 (end of treatment), and 18 (end of posttreatment follow-up). Medication containers were weighed during the study to monitor usage and adherence.
The PASI scores from week 12 (with last observation carried forward for missing scores) and week 18 (from study completers only) were used in the analyses. The cost-effectiveness of each treatment was based on the model described by Hankin et al8 for systemic treatments of moderate to severe psoriasis. Cost-effectiveness was calculated on a “per gram” and “containers needed for optimal treatment”9 basis at weeks 12 and 18. Calculation methods are summarized in Table 1; PASI changes in Table 2; and medication cost assumptions and results in Table 3.
Sixty patients with moderate plaque psoriasis were enrolled. Fifty-five completed treatment, and 43 returned for the 18-week follow-up visit (Table 2).
The LCD treatment produced greater improvement in PASI score (58.2%) at less cost ($0.92 per 1% improvement in PASI, or “PASI-1”) than calcipotriol treatment (36.5% at $35.42 per PASI-1) after 12 weeks of treatment. After treatment and 6 weeks of follow-up (at week 18), the cost of PASI-1 was $1.01 in the LCD group and $58.11 in the calcipotriol group because the LCD group maintained PASI improvement (52.5%), while PASI in the calcipotriol group significantly worsened (to 22.2%). Furthermore, the expected costs for achieving PASI-50 and PASI-75 with each therapy choice were also less for LCD than for calcipotriol (Table 3).
For a patient choosing between LCD solution ($45 retail price) and calcipotriol cream (an estimated $25 copayment), the predicted cost of successful therapy was lower with LCD than with calcipotriol owing to better clinical response with LCD solution (Table 3). From an insured patient's perspective, the copayment for prescribed calcipotriol cream would have to drop to less than $20 per tube to match the cost-effectiveness of the OTC LCD solution.
Patients would need twice as many tubes of calcipotriol cream as bottles of LCD solution for 12 weeks of successful treatment and might need 1 to 3 additional tubes of calcipotriol cream to sustain a PASI-75 response for 18 weeks (Table 3).
To test the model, cost-of-treatment calculations were repeated with data from successfully treated patients. The actual cost of PASI-75 in the calcipotriol group could not be calculated owing to lack of responders, but PASI-75 achievers in the LCD group used 258.3 g (2-3 bottles) of LCD solution at an average treatment cost of $68.36, which is close to the $68.63 wholesale cost per PASI-75 predicted by the model (Figure).
The LCD solution was a more cost-effective treatment option than calcipotriol cream in this study, demonstrating a superior and longer-lasting therapeutic effect than prescription calcipotriol cream at a lower cost to a third-party payer and even to an insured patient.
A limitation of this study is that cost-effectiveness was calculated based on usage and clinical outcomes in a limited sample of patients with 3% to 15% BSA involvement over a single 18-week episode of psoriasis. The study was not powered to detect uncommon safety issues, but the number of subjects (n = 60), including the planned 20% dropouts, was sufficient to detect statistical differences in efficacy between the groups. The cost-effectiveness analysis did not take into account the cost of clinic visits or adverse reactions; however, since the adverse reactions were minor, it is unlikely that the cost of managing adverse reactions would substantially change the results.
The LCD solution treated moderate plaque psoriasis at a lower cost with a smaller amount of medication needed to achieve significant and persistent improvements in disease severity compared with calcipotriol cream. Over-the-counter 15% LCD solution can be a cost-effective, clinically acceptable, and easily accessible treatment option for patients with psoriasis, regardless of their health insurance coverage.
Correspondence: Dr Kimball, Clinical Unit for Research Trials in Skin, Massachusetts General Hospital, 50 Staniford St, Ste 240, Boston, MA 02114 (firstname.lastname@example.org).
Accepted for Publication: February 6, 2010.
Author Contributions: Drs Alora-Palli and Kimball had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Alora-Palli, Brouda, Green, and Kimball. Acquisition of data: Alora-Palli and Kimball. Analysis and interpretation of data: Brouda and Kimball. Drafting of the manuscript: Alora-Palli, Brouda, and Kimball. Critical revision of the manuscript for important intellectual content: Brouda, Green, and Kimball. Statistical analysis: Brouda and Kimball. Obtained funding: Green. Administrative, technical, and material support: Alora-Palli and Brouda. Study supervision: Green and Kimball.
Financial Disclosure: Drs Alora-Palli and Kimball are investigators for, and Dr Kimball served as a consultant to, NeoStrata Company Inc at the time of this study. Mss Brouda and Green are employed by NeoStrata.
Funding/Support: This study was supported in full by a grant from NeoStrata Company Inc.
Role of the Sponsors: The sponsors assisted with the analysis of the data and the preparation, review, and approval of the manuscript.
Additional Contributions: Dror Rom, PhD, assisted with the statistical analysis of clinical efficacy.
Trial Registration: clinicaltrials.gov Identifier: NCT00705900