Introduction
Eculizumab is a fully humanized monoclonal blocking antibody to
complement protein C5 that inhibits cleavage to C5a and C5b, thus
preventing terminal complement complex C5b-9 and formation of the
membrane attack complex.1 Eculizumab was FDA approved
in 2020 for the treatment of neuromyelitis optica (NMO) after it was
shown to be effective in reducing relapse frequency in highly clinically
active, aquaporin-4 immunoglobulin G (AQP4-IgG)-positive
NMO.2 Commonly reported side effects
(>10%) include upper respiratory infections and headache.
A life-threatening desquamating rash and hyperammonemia following
administration of eculizumab for paroxysmal nocturnal hemoglobinuria
(PNH) has been reported.3 Cutaneous adverse drug
reactions can range from self-limited cutaneous eruptions such as
maculopapular exanthema to severe cutaneous drug reactions. Severe
cutaneous adverse reactions are rare, potentially life-threatening, and
T-cell mediated hypersensitivity reactions.4 Certain
drugs can induce autoantibodies rather than cause an
autoantibody-associated disease. The information available suggests
eculizumab is unlikely to do this.5 We report a
patient with refractory NMO who developed a cutaneous drug reaction
following intravenous eculizumab administration. This information will
be useful to clinicians, given the expanding clinical uses of eculizumab
in diseases such as atypical hemolytic uremic syndrome (aHUS), PNH, and
myasthenia gravis.6-8 Eculizumab has also been used
for lupus nephritis-associated thrombotic microangiopathy in systemic
lupus erythematosus patients.9