Secukinumab Emerges as a Rapidly Effective Therapy for Pityriasis Rubra Pilaris
Refractory pityriasis rubra pilaris (PRP) often is treated off-label with the same biologic therapies that are approved for the treatment of psoriasis, most commonly tumor necrosis factor (TNF) α antagonists and ustekinumab; however, the IL-17A antagonist secukinumab also has shown efficacy in the treatment of PRP. We report 2 new cases of severe refractory PRP that responded rapidly to treatment with secukinumab.
Practice Points
- In patients with pityriasis rubra pilaris (PRP) who have not responded to topical treatments, off-label treatment with systemic therapies approved for plaque psoriasis can be considered.
- Secukinumab, an IL-17A antagonist, has shown particularly striking results in the treatment of PRP.
Comment
Because there are no formal treatment guidelines for refractory PRP, case reports play an important role in clinical decision-making. When a patient is unresponsive to topical medications and first-line traditional systemic therapies (eg, methotrexate, cyclosporine, acitretin), biologic drugs effective in the treatment of psoriasis are widely accepted as the next therapeutic step.1 The biologic medications that are most often reported in the treatment of PRP are the TNF-α antagonists, as they have been available the longest.1-2 In a systematic review of 15 patients with PRP who were treated with TNF-α antagonists,2 80% of patients achieved complete response (mean time to maximal response, 5 months). There also are a number of reports of successful treatment of PRP with the IL-12/23 antagonist ustekinumab, which has been commercially available since 2009.5-9 Although improvement was noted in most of these patients at the time of the second injection (week 4 of therapy), maximal response with ustekinumab typically occurs between weeks 12 and 28.10
In our cases of PRP treated with secukinumab as well as 2 others that were recently reported in the literature, resolution of erythema and plaques was rapid. This superiority of the response rate parallels the performance of secukinumab relative to ustekinumab in patients with psoriasis11 In one case of a 67-year-old man with PRP treated with secukinumab, scaling and pruritus were reduced by week 3 of treatment and erythema had cleared by week 8.3 In another case of a 33-year-old woman with PRP, pruritus resolved after 1 week of treatment and erythematous plaques and palmoplantar keratoderma improved by week 2.4 In both of our cases, plaques had resolved or nearly resolved by week 4 of follow-up. Patient 1 achieved complete response at week 8 of therapy. Patient 2 never attained complete response, but by week 12 she achieved maximal response, which still resulted in markedly increased quality of life. We do not intend to make additions to her treatment plan because she is currently the clearest she has been since onset of symptoms and is happy with her present condition.
Although it is difficult to predict the long-term prognosis in our 2 patients, we will continue their current regimens indefinitely—as long as the response persists and no adverse events are experienced. This approach is consistent with guidelines for management of plaque psoriasis with secukinumab.12
,This accumulation of evidence suggests the importance of the role of IL-17 in the pathogenesis of PRP. The serum level of IL-17 was not evaluated in our patients, but elevation of IL-17 has been reported in a case of PRP.13 Further studies are needed to clarify the role of IL-17 in this disease entity.
Conclusion
Given the refractory nature of PRP and the relative safety of targeted immunotherapy, trials of new biologics and potent small molecules approved for psoriasis treatment are worth exploring for PRP. In light of our reports and those in the literature and given the relative safety of anti–IL-17 agents, it may be reasonable to consider such agents as a first-line therapy for this predictably refractory disease.
