Monitor serum transaminases and bilirubin prior to initiation of KADCYLA treatment and prior to each KADCYLA dose. Patients with known active hepatitis B virus or hepatitis C virus were excluded from Study 1 [see Clinical Studies (14.1)]. Reduce the dose or discontinue KADCYLA as appropriate in cases of increased serum transaminases and/or total bilirubin [see Dosage and Administration (2.2)]. Permanently discontinue KADCYLA treatment in patients with serum transaminases > 3 × ULN and concomitant total bilirubin > 2 × ULN. KADCYLA has not been studied in patients with serum transaminases > 2.5 × ULN or bilirubin > 1.5 × ULN prior to the initiation of treatment.
 
In clinical trials of KADCYLA, cases of nodular regenerative hyperplasia (NRH) of the liver have been identified from liver biopsies (3 cases out of 884 treated patients). Two of these three cases of NRH were observed in the randomized trial (Study 1) [see Adverse Reactions (6.1)]. NRH is a rare liver condition characterized by widespread benign transformation of hepatic parenchyma into small regenerative nodules; NRH may lead to non-cirrhotic portal hypertension. The diagnosis of NRH can be confirmed only by histopathology. NRH should be considered in all patients with clinical symptoms of portal hypertension but with normal transaminases and no manifestations of cirrhosis. Upon diagnosis of NRH, KADCYLA treatment must be permanently discontinued.
 

5.2 Left Ventricular Dysfunction
 
Patients treated with KADCYLA are at increased risk of developing left ventricular dysfunction. A decrease of LVEF to < 40% has been observed in patients treated with KADCYLA. In the randomized trial (Study 1), left ventricular dysfunction occurred in 1.8% of patients in the KADCYLA-treated group and 3.3% of patients in the lapatinib plus capecitabine-treated group [see Adverse Reactions (6.1)].
 
Assess LVEF prior to initiation of KADCYLA and at regular intervals (e.g. every three months) during treatment to ensure the LVEF is within the institution's normal limits. Treatment with KADCYLA has not been studied in patients with LVEF < 50% prior to initiation of treatment. If, at routine monitoring, LVEF is < 40%, or is 40% to 45% with a 10% or greater absolute decrease below the pretreatment value, withhold KADCYLA and repeat LVEF assessment within approximately 3 weeks. Permanently discontinue KADCYLA if the LVEF has not improved or has declined further [see Dosage and Administration (2.2)]. Patients with a history of symptomatic congestive heart failure (CHF), serious cardiac arrhythmia, or history of myocardial infarction or unstable angina within 6 months were exc