Tumor Necrosis Factor α Inhibitors in the Treatment of Toxic Epidermal Necrolysis

Biologic TNF-α Antagonists

Following the PTX case report and the thalidomide trial, there was increased interest in using newer-generation TNF-α inhibitors, such as the monoclonal antibody infliximab or the fusion protein etanercept, in the treatment of TEN. To date, there are 10 known published case reports,^{11,12,15-21,23} 3 case series,^13,14,22 and 1 trial²⁴ describing the use of these agents; however, treatment protocols vary. Categories of treatment protocols include the use of TNF-α inhibitors as monotherapy, following failure of other systemic agents, and in combination with other systemic therapies.

TNF-α Inhibitors as Monotherapy
Review of the literature yielded 2 case reports using infliximab monotherapy^11,12 and 2 case series using infliximab or etanercept monotherapy^13,14 with a total of 14 patients (Table 1). Fischer et al¹¹ was the first of these reports to describe a patient successfully treated with supportive care and a single dose of infliximab 5 mg/kg. The dose was given 4 days after the onset of symptoms, and the rapid progression of the disease was stopped, with complete recovery in less than 4 weeks.¹¹ Hunger et al¹² also described the successful treatment of a patient using a similar protocol: a single dose of infliximab 5 mg/kg given 3 days after symptom onset. Epidermal detachment was abated within 24 hours and the patient had almost complete reepithelialization within 5 days.¹² In a case series published by Zárate-Correa et al,¹³ 2 patients with near 100% body surface area involvement were successfully treated with a single dose of infliximab 300 mg. Although both of these patients experienced fairly rapid recoveries, one patient’s course was complicated by methicillin-resistant Staphylococcus aureus bacteremia.¹³ Paradisi et al¹⁴ described 10 consecutive patients treated with a single dose of etanercept 50 mg given within 6 hours of hospital admission and within 72 hours of symptom onset. The SCORTEN (SCORe of Toxic Epidermal Necrolysis) scale—a severity-of-illness assessment for TEN based on body surface area involvement, comorbidities, and metabolic abnormalities—was used to predict mortality in these patients. The investigators reported an expected mortality of 46.9%; however, the observed mortality was 0%, and there were no reported infections.¹⁴

TNF-α Inhibitors Following Failure of Other Systemic Agents in TEN
Seven case reports and 1 case series using anti–TNF-α therapy following failure of other systemic agents were reviewed for a total of 9 patients (3 pediatric/adolescent patients, 6 adult patients)(Table 2).^13,15-21 Seven patients were treated with infliximab,^{13,15,17,19-21} and the remaining 2 patients were treated with etanercept.^16,18 All patients were treated initially with corticosteroids and/or IVIG. In each case, anti–TNF-α therapy was introduced when prior treatment failed to halt the progression of TEN. Most reports claimed a rapid and beneficial response to anti–TNF-α therapy. Eight of 9 (88.9%) patients recovered.^13,15,17-21 Famularo et al¹⁶ described 1 patient who was treated with 2 doses of etanercept following prednisolone but died on the tenth day of hospitalization secondary to disseminated intravascular coagulation and multiorgan failure; however, the patient reportedly had near-complete reepithelialization of the skin on the sixth day of the hospital course.¹⁶ Of the 8 surviving patients, 3 (37.5%) experienced hospital courses complicated by nosocomial gram-negative bacteremia, including Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae.^13,15 Interestingly, a patient described by Worsnop et al²⁰ developed erosive lichen planus of the mouth and vulva 31 days after infliximab infusion.

Combination of TNF-α Inhibitor With Other Systemic Agents in TEN
One case series²² and 1 case report²³ using infliximab in combination with other systemic therapies were reviewed with a total of 4 patients (Table 3). Both reports utilized the same treatment protocol, which consisted of a single bolus of intravenous methylprednisolone 500 mg followed by a single dose of infliximab 5 mg/kg and then IVIG 2 g/kg over 5 days. Three of 4 (75%) patients recovered.^22,23 Gaitanis et al²² reported a patient who died on the ninth day of hospitalization secondary to multiorgan dysfunction caused by a catheter-related bacteremia. Similar to the patient described by Famularo et al,¹⁶ this patient also was noted to have remarkably improved skin prior to death. Two of the other 3 patients that survived had their hospital course complicated by infection, requiring antibiotics.²² In the Gaitanis et al²² series, the average predicted mortality according to a SCORTEN assessment was 50.8%; however, mortality was observed in 33.3% (1/3) of patients in the case series.

N-Acetylcysteine and Infliximab
The combination of NAC and infliximab was studied in a randomized controlled trial using TNF-α inhibition in TEN.²⁴ In this study, 10 patients were admitted to a burn unit and treated with either 3 doses of intravenous NAC (150 mg/kg per dose) plus 1 dose of infliximab 5 mg/kg or NAC alone. Unlike some of the previously described articles, Paquet et al²⁴ utilized an illness auxiliary score (IAS), which predicts both disease duration and mortality. An IAS was taken at admission and again 48 hours after completion of NAC and/or infliximab administration. The mean clinical IAS score was reported to have remained unchanged at treatment completion in the NAC group and slightly worsened in the NAC-infliximab group. One patient died in the NAC group and 2 patients died in the NAC-infliximab group, each due to infection. These fatalities corresponded to a mean mortality of 20% in the NAC-treated group and 40% for the NAC-infliximab group. To compare, the predicted mortalities based on the IAS were 20.4% and 21.4%, respectively.²⁴