Treatment and impact on immunotherapy
Table 4 summarizes the ICI classes, treatments for rash, impact on
immunotherapy, and response to dermatologic therapy or interruption of
immunotherapy according to the grade of cutaneous irAE.
The combined use of anti–PD-1 and anti–CTLA-4 antibodies tended to be
associated with a higher grade of rash. Grade 3 rash was observed in
patients receiving anti–PD-1 therapy (n = 2) and combined anti–PD-1
and anti–CTLA-4 therapy (n = 1).
In our study, 20 of 42 (47.6%) rashes were treated with systemic
steroids, namely prednisolone at doses of <0.4 (7/20, 35.0%),
0.4–1.0 (7/20, 35.0%), and >1.0 mg/kg (6/20, 30%). In
two cases, steroid pulse therapy (intravenous methylprednisolone 1000
mg/day for 3 consecutive days) was used. Both patients were receiving
combination therapy with anti–PD-1 and anti–CTLA-4 antibodies, and
both rashes were maculopapular rashes. In the case of psoriasiform
reaction (n = 1), topical active vitamin D was added to topical steroid
and systemic antihistamine.
Interruption of ICI therapy occurred in multiple rash types because of
the eruption severity. In total, 7 of 42 cases (16.7%) resulted in
temporary interruption, and 19 of 42 cases (45.2%) resulted in
permanent discontinuation. Most patients who developed extracutaneous
irAEs required temporary treatment interruption (2/10) or permanent
discontinuation (7/10) regardless of the rash grade of rash.
In total, 40 of 42 (95.2%) rashes (including those that were
exacerbated on subsequent ICI administration) improved with appropriate
dermatologic therapy, interruption of immunotherapy, or both. Only 2 of
42 (4.8%) rashes did not respond to dermatologic treatment and
interruption of immunotherapy.