Since 2014, i.e. three years before cladribine tablets were EMA licensed for highly active MS, we have treated well over 200 pwMS using injectable (s.c.) cladribine as an off-label immunotherapy. This has been a well received programme that helped a number of pwMS access treatment, who were either not eligible for licensed disease-modifying treatments (DMT), or chose our off-label offering over licensed DMT. We published our first experience with this just over one year ago (https://www.ncbi.nlm.nih.gov/pubmed/30419510); a second manuscript is in draft.
However, our early involvement with cladribine in clinical practice also gave us insights into a less common adverse risk, and we can now report three pwMS who developed severe allergic skin reactions (SASR) in the context of this treatment. SASR is not unheard of in people who receive cladribine for hairy cell leukaemia, the condition that gave cladribine its original license 25 years ago. However, in pwMS we hadn’t seen this before. Whether SASR may also occur with the tablet version of cladribine (MAVENCLAD®) we don’t know, but I wouldn’t be surprised if this would happen on occasion. The good news is that standard management using steroids, anti-histamines, and topical medication effectively suppressed SARS in our three pwMS. Taking steroids & anti-histamines prior to their second cladribine course prevented SARS in 2/3, whilst 1/3 chose not to have a further dose.
Figure legend A. Facial erythema and oedema, erythematous plaques on the arms with some targetoid central dusky erythema, papulovesicular lesions on the trunk with confluent erythematous plaques on the upper chest in Patient 1. B. Maculopapular eruption on the trunk and limbs with some psoriasiform scale on the trunk in Patient 2. C. Erythema and swelling upper eyelids and cheeks bilaterally with confluent erythema and oedema both forearms with tense bullae with serous exudate on the dorsolateral aspect of the left wrist.
CoI: I have received honoraria and/or meeting support from Biogen, Lipomed, Merck Serono, Novartis, Roche, Sanofi Genzyme, and Teva.