For example, osimertinib, the 3rd generation of EGFR TKI targeting EGFR T790M; L858R (TL) mutations, is a cysteine-directed covalent drug that less-specifically binds to cysteine-rich tissues, including lung and spleen causing interstitial lung disease, diarrhoea, and hyperglycaemia [45, 46]. The gene discussed is EGFR; the disease is interstitial lung disease.