Cost-effectiveness of a fixed combination of hydroquinone/tretinoin/fluocinolone cream compared with hydroquinone alone in the treatment of melasma

Journal of Drugs in Dermatology, Feb, 2007 by Tania Cestari, Lucie Adjadj, Margaret Hux, Maria Regina Shimizu, Vincent Pierre Rives

A payer perspective was applied to evaluate the cost-effectiveness of choosing to treat melasma with TCT once daily or with a standard regimen of hydroquinone 4% alone (HQ) twice daily; and the comparison between these alternatives was evaluated over an 8-week period. The economic evaluation was based on the trial population (ie, those patients presenting to a dermatologist with moderate to severe facial melasma and considering treatment). All patients were assumed to be using a strong broad-spectrum sunscreen (SPF 30) product and avoiding exposure to the sun as proposed by the protocol. Treatment effectiveness was considered as the proportion of patients to show primary success or complete clearing of melasma (melasma score 0, or melasma lesions very similar to surrounding normal skin), since it is the most important clinical outcome for patients as well as the trial's primary outcome measure.

Melasma-related cost over the 8-week period in each of the 5 countries was calculated based on the average usage of TCT or HQ from the clinical trial. The estimated cost of the TCT was based on the cost of Tri-luma. Claripel[TM] was the HQ product selected for price since it was the product used in the trial. Any adverse events considered potentially related to melasma treatments and found have statistically significant increases in either group were considered relevant to the economic evaluation, as were subsequent treatments for patients who failed to achieve complete or substantial clearing. However, health resources for treatment of these adverse events or other resources, such as unscheduled visits to other healthcare providers for a skin condition, were not collected within the trial. This evaluation assumes that treatment received during the trial is representative of medication use for these countries. Costs are, therefore, presented for each country of interest (US, Brazil, Chile, Argentina, and Colombia) based on the size of the tube and 2004 local currency price for the TCT and the HQ studied in the clinical trial. No discounting was performed due to the short time horizon.

The analysis was conducted in 2 stages. Initially, a choice of "treating melasma" versus "not treating" was evaluated for each treatment separately. This analysis used a ratio of the cost for treatment over the 8 weeks to the proportion of patients who showed complete clearing using either TCT or HQ. This can be considered as an incremental comparison between each treatment and the option of not treating. Secondly, the active treatments TCT and HQ were compared to each other using an incremental cost-effectiveness ratio.

There were several sensitivity analyses varying the assumptions and parameters of treatment usage. The effectiveness observed during the trial was varied using the upper 95% confidence interval (CI) and lower 95% CI of the success rate in the TCT group to assess impact on cost-effectiveness. A sensitivity analysis was conducted using an alternate cost of HQ for the most prescribed agent. IMS pharmaceutical market research data were used to identify the appropriate product. (23) The impact of varying the estimated amount of product effectively used was assessed by means of sensitivity analysis with the upper 95% confidence limit of quantity of TCT cream used during the trial. Finally, a sensitivity analysis was conducted including wastage, assuming that a whole number of tubes would need to be purchased, and this wastage could vary depending on the tube sizes available in each country.