Literature regarding the effect of biologics on the course of mycosis fungoides (MF) is scarce. This multicentre study analysed retrospective data on 19 patients with MF, who were treated with biologics; 12 for inflammatory conditions coexisting with MF, and 7 for MF misdiagnosed as an inflammatory skin disease. Eight patients were treated with anti-tumour necrosis factor-α-monotherapy; 6 had early-stage MF, in 3 patients MF preceded and in 3 MF was diagnosed after initiation of biologics, with no stage-progression or with stable disease, respectively (median treatment time concurrent with MF 57 months). Two patients had advanced stage MF: IIB, treated for 15 months with no stage-progression, and IVA1, treated for 8 months, died of disease 10 months later. The other 11/19 patients received anti-interleukin-17A and/or anti-interleukin-12/23 or anti-interleukin-23 (with/without anti-tumour necrosis factor-α/anti-interleukin-4/13), with stage-progression in 8 patients after a median of 8 months' treatment. Although, in general, biologics should be avoided in patients with MF, these results indicate that anti-tumour necrosis factor-α-monotherapy might not aggravate the disease course in early-stage patients. Interleukin-17A, interleukin-12/23 and interleukin-23 pathway-blockers may prompt progression of MF.
Keywords: anti-IL-12/23; anti-IL17A; anti-IL23; anti-TNFα; biologic treatment; mycosis fungoides; cutaneous T cell lymphoma.