Current status of DILD in molecular targeted therapies.

Molecular targeted drugs have become the mainstream for cancer therapy, and they have contributed to improving the outcome for cancer patients. On the other hand, molecular targeted drugs are associated with a variety of adverse drug reactions. Drug-induced interstitial lung disease (DILD) is a typical adverse drug reaction that has been an important problem with regard to safety management during cancer treatment. In the past, there was a lack of detailed and accurate epidemiological data about DILD. However, most of the molecular targeted drugs have been subject to all-case post-marketing surveillance since gefitinib-induced ILD became a concern. These surveillance data present useful information about DILD, such as frequency of adverse events, mortality, and risk factors, and as a result, the epidemiological profile of DILD associated with molecular targeted drugs has become apparent during the past decade. Further, it has been considered that the principal management for DILD is early detection and cessation of the suspected cause. However, ILD associated with everolimus and temsirolimus requires unusual management; i.e., patients with asymptomatic ILD are allowed to continue treatment with everolimus or temsirolimus, and even after symptomatic ILD, both everolimus and temsirolimus are allowed to be readministered after the resolution of ILD. As a result of the collected data, a change has begun in the field of DILD associated with molecular targeted drugs. The features of DILD can differ for each drug, and clinicians should thus keep this information about DILD in mind while treating patients.