Evaluating Therapies in Pemphigus Vulgaris
In general, the quality of published data concerning the therapy of PV is poor. There are few good-quality randomized controlled trials (RCTs). The majority of data are confined to case reports and small case series in which cases of PV of variable severity may be included, often with other subtypes of pemphigus. Follow-up periods are often short, even in the larger trials, and dosing schedules vary widely. Trial design is often poor, with different drug combinations used in different arms such that any differences in outcomes cannot be attributed to a single intervention. Controls are often indirect, involving comparisons of remission and mortality rates with historical controls, or comparison of maintenance corticosteroid doses before and after the addition of a given therapy. A huge number of outcome measures and disease definitions have also been used, making comparison between studies difficult. Finally, the rarity of PV means recruitment of sufficient numbers of patients is challenging; many studies are small and underpowered.
To address some of these issues, the International Pemphigus Committee has produced a consensus statement that outlines definitions of important time points and disease status. In parallel, efforts are being made to use commonly accepted disease severity scores.[32,33] By using a commonly accepted set of core outcome measures, it is envisaged that trial data can be better compared and pooled such that small and underpowered individual studies could become of value as it would be possible to include them in larger meta-analyses. In addition, it is now widely acknowledged that the rarity of PV means cooperative research with multiple recruitment sites is needed to produce successful trials with adequate power. It has been estimated that to demonstrate a 20% difference between interventions with 80% power, a study of more than 196 patients would be needed in PV. Trials such as these, using a set of core outcome measures, are coming into being but at present, in most studies, it is difficult to judge the effect of individual drugs and make firm treatment recommendations. In these guidelines, we have listed the highest ranking level of evidence and given an overall recommendation for each therapy. A summary of treatment options is given in Table 4.
The British Journal of Dermatology. 2017;177(5):1170-1201. © 2017 Blackwell Publishing