Efficacy of Etanercept in the Treatment of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Comment

There is no definitive gold standard treatment of SJS, SJS/TEN overlap, or TEN. However, generally agreed upon management includes immediate discontinuation of the offending medication and supportive therapy with aggressive electrolyte replacement and wound care. Management in a burn unit or intensive care unit is recommended in severe cases. Contention over the efficacy of various medications in the treatment of SJS and TEN continues and largely is due to the rarity of SJS and TEN; studies are small and almost all lack randomization. Therapies that have been used include high-dose steroids, IVIG, plasmapheresis, cyclophosphamide, cyclosporine A, and TNF inhibitors (eg, etanercept, infliximab).¹

Evidence for the use of anti–TNF-α antibodies has been limited thus far, with most of the literature focusing on infliximab and etanercept. Adalimumab, a fully humanized clonal antibody, has no reported cases in the dermatologic literature for use in patients with SJS/TEN. Two case reports of adalimumab paradoxically causing SJS have been documented. In both cases, adalimumab was stopped and patients responded to intravenous corticosteroids and infliximab.^7,8 Similarly, thalidomide has not proven to be a promising anti–TNF-α agent for the treatment of SJS/TEN. In the only attempted randomized controlled trial for SJS and TEN, thalidomide appeared to increase mortality, eventuating in this trial being terminated prior to the planned end date.⁹Infliximab and etanercept have several case reports and a few case series highlighting potentially efficacious application of TNF-α inhibitors for the treatment of SJS/TEN.^10-13 In 2002, Fischer et al¹⁰ reported the first case of TEN treated successfully with a single dose of infliximab 5 mg/kg. Kreft et al¹⁴ reported on etoricoxib-induced TEN that was treated with infliximab 5 mg/kg, which led to re-epithelialization within 5 weeks (notably a 5-week re-epithelialization time is not necessarily an improvement).

In 2005, Hunger et al³ demonstrated TNF-α’s release by KCs in the epidermis and by inflammatory cells in the dermis of a TEN patient. Twenty-four hours after the administration of infliximab 5 mg/kg in these patients, TNF-α was found to be below normal and epidermal detachment ceased.³ Wojtkietwicz et al¹³ demonstrated benefit following an infusion of infliximab 5 mg/kg in a patient whose disease continued to progress despite treatment with dexamethasone and 1.8 g/kg of IVIG.

Then 2 subsequent case series added further support for the efficacy of infliximab in the treatment of TEN. Patmanidis et al¹⁵ and Gaitanis et al¹⁶ reported similar results in 4 patients, each treated with infliximab 5 mg/kg immediately followed by initiation of high-dose IVIG (2 g/kg over 5 days). Zárate-Correa et al¹⁷ reported a 0% mortality rate and near-complete re-epithelialization after 5 to 14 days in 4 patients treated with a single 300-mg dose of infliximab.

However, the success of infliximab in the treatment of TEN has been countered by the pilot study by Paquet et al,¹⁸ which compared the efficacy of 150 mg/kg of N-acetylcysteine alone vs adding infliximab 5 mg/kg to treat 10 TEN patients. The study demonstrated no benefit at 48 hours in the group given infliximab, the time frame in which prior case reports touting infliximab’s benefit claimed the benefit was observed. Similarly, there was no effect on mortality for either treatment modality as assessed by illness auxiliary score.¹⁸

Evidence in support of the use of etanercept in the treatment of SJS/TEN is mounting, and some centers have begun to use it as the first-choice therapy for SJS/TEN. The first case was reported by Famularo et al,¹⁹ in which a patient with TEN was given 2 doses of etanercept 25 mg after failure to improve with prednisolone 1 mg/kg. The patient showed near-complete and rapid re-epithelization in 6 days before death due to disseminated intravascular coagulation 10 days after admission.¹⁹ Gubinelli et al²⁰ and Sadighha²¹ independently reported cases of TEN and TEN/acute generalized exanthematous pustulosis overlap treated with a total of 50 mg of etanercept, demonstrating rapid cessation of lesion progression. Didona et al²² found similar benefit using etanercept 50 mg to treat TEN secondary to rituximab after failure to improve with prednisone and cyclophosphamide. Treatment of TEN with etanercept in an HIV-positive patient also has been reported. Lee et al²³ described a patient who was administered 50-mg and 25-mg injections on days 3 and 5 of hospitalization, respectively, with re-epithelialization occurring by day 8. Finally, Owczarczyk-Saczonek et al²⁴ reported a case of SJS in a patient with a 4-year history of etanercept and sulfasalazine treatment of rheumatoid arthritis; sulfasalazine was stopped, but this patient was continued on etanercept until resolution of skin and mucosal symptoms. However, it is important to consider the possibility of publication bias among these cases selected for their positive outcomes.

Perhaps the most compelling literature regarding the use of etanercept for TEN was described in a case series by Paradisi et al.² This study included 10 patients with TEN, all of whom demonstrated complete re-epithelialization shortly after receiving etanercept 50 mg. Average SCORTEN was 3.6 with a range of 2 to 6. Eight patients in this study had severe comorbidities and all 10 patients survived, with a time to re-epithelialization ranging from 7 to 20 days.² Additionally, a randomized controlled trial showed that 38 etanercept-treated patients had improved mortality (P=.266) and re-epithelialization time (P=.01) compared to patients treated with intravenous methylprednisolone.²⁵Limitations to our study are similar to other reports of SJS/TEN and included the small number of cases and lack of randomization. Additionally, we do not have data available for all patients for time between onset of disease and treatment initiation. Because of these challenges, data presented in this case series is observational only. Additionally, the patients treated with etanercept alone had a slightly lower SCORTEN compared to the group that received IVIG or supportive care alone (2.1 and 2.4 respectively). However, the etanercept-only group actually had higher involvement of epidermal detachment (33%) compared to the non-etanercept group (23%).

Conclusion

Although treatment with etanercept lacks the support of a randomized controlled trial, similar to all other treatments currently used for SJS and TEN, preliminary reports highlight a benefit in disease progression and improvement in time to re-epithelialization. In particular, if etanercept 50 mg subcutaneously is given as monotherapy or is given early in the disease course (prior to other therapies being attempted and ideally within 6 hours of presentation), our data suggest an even greater trend toward improved mortality and decreased time to re-epithelialization. Additionally, our findings may suggest that in some patients, etanercept monotherapy is not an adequate intervention but the addition of IVIG may be helpful; however, the senior author (S.W.) notes anecdotally that in his experience with the patients treated at the University of California Los Angeles, the order of administration of combination therapies—etanercept followed by IVIG—was important in addition to the choice of therapy. These findings are promising enough to warrant a multicenter randomized controlled trial comparing the efficacy of etanercept to other more commonly used treatments for this spectrum of disease, including IVIG and/or cyclosporine. Based on the data presented in this case series, including the 13 patients who received etanercept and had a 0% mortality rate, etanercept may be viewed as a targeted therapeutic intervention for patients with SJS and TEN.