With the rapid expansion in the development and clinical
utility
of immune checkpoint inhibitors (ICIs) for oncology, the continual
evaluation of the safety profile of such agents is imperative. The
safety profile of ICIs as monotherapy is dominated by immune-related
adverse events, which can be considered as an extension of the mechanism
of action of these immunomodulatory drugs. Further to this, an emerging
theme is that ICI treatment can significantly impact upon the tolerability
of coadministered medications. Numerous reports in literature indicate
that ICIs may alter the immunological perception of coadministered
drugs, resulting in undesirable reactions to a variety of concomitant
medications. These reactions can be severe in manifestation, including
hepatotoxicity and Stevens-Johnson Syndrome (SJS)/toxic epidermal
necrolysis (TEN), but may also have detrimental impact on malignancy
control. To minimize the impact of such drug–drug interactions
on patients, it is imperative to identify medications that may cause
these reactions, understand the underlying mechanisms, consider the
timing and dosing of comedication, and explore alternative medications
with comparable efficacies. Improving our understanding of how concomitant
medications affect the safety and efficacy of ICIs can allow for potential
culprit drugs to be identified/removed/desensitized. This approach
will allow the continuation of ICI therapy that may have been discontinued
otherwise, thereby improving malignant control and patient and drug
development outcomes.