Abstract P5-18-03: Hepatopulmonary syndrome with long term use of ado-trastuzumab emtansine (T-DM1)

Abstract Introduction: Hepatopulmonary syndrome (HPS) is characterized by hypoxemia, portal hypertension, and intrapulmonary shunting and manifests as dyspnea. The portal hypertension may be a result of cirrhosis or non-cirrhotic causes such as nodular regenerative hyperplasia of the liver that is associated with drug therapy. Progressive hypoxemia often occurs despite stable liver function. Ado-trastuzumab emtansine (T-DM1; KADCYLA) is an antibody-drug conjugate comprised of a humanized monoclonal antibody trastuzumab covalently linked to the cytotoxic agent maytansine. T-DM1 is prescribed in the postneoadjuvant setting in persons with residual invasive HER2-positive (HER2+) breast cancer (BC) as well as in persons with metastatic HER2+ BC who were previously treated with trastuzumab and a taxane. Liver toxicities including an asymptomatic, transient increase in transaminases and nodular regenerative hyperplasia that results in portal hypertension have been described; however, HPS secondary to noncirrhotic portal hypertension occurring with long-term exposure to T-DM1 has not been reported. We have identified patients (pts) with this infrequent, yet serious complication, and we aim to better characterize their clinical course to guide earlier detection and hopefully prevent irreversible hypoxic respiratory failure. Methods: Institutional search tools were utilized to identify pts at Mayo Clinic with HER2+ BC treated with T-DM1 in either the postneoadjuvant or metastatic setting. Electronic health records were manually reviewed for HPS criteria including 1) hypoxemia 2) portal hypertension and 3) intrapulmonary shunt/vasodilation confirmed by contrast echocardiogram or macroaggregated albumin lung perfusion scan. For pts meeting criteria for HPS, imaging was independently reviewed by a hepatologist to determine whether there was preexisting liver disease or if changes occurred after initiation of T-DM1. Results: We identified 259 pts with HER2+ BC treated with T-DM1 in the postneoadjuvant (n=70) or metastatic setting (n=185). Four pts met criteria for HPS (1.5%) while receiving T-DM1 for metastatic disease (Table 1; listed in chronological order of onset of HPS). Median age was 43 (range 35 - 53 years), median prior lines of treatment was 1.5 (range 0 - 7), and the median number of cycles of T-DM1 prior to discontinuation was 68.5 (range 51 - 90). All pts had evidence of left atrial enlargement on echocardiogram, and evidence of portal hypertension as determined by the presence of varices, and splenomegaly. Three pts had documented telangiectasias as well as Grade 1-2 elevations in serum transaminases and bilirubin. Elevations in hemoglobin were noted in 2 pts during treatment with T-DM1. All pts had a confirmed intrapulmonary shunt via contrast echocardiogram and a lung perfusion scan. Three pts discontinued T-DM1 after diagnosis of HPS and experienced some clinical improvement in hypoxia. One pt died two months after stopping T-DM1 due to progression of BC. Conclusion: HPS may occur in the setting of prolonged exposure to T-DM1 and can be associated with severe hypoxic respiratory failure. Further data are required to characterize the spectrum of liver injury that occurs with long-term use of T-DM1 to provide further guidance to clinicians as regards monitoring for these adverse effects. Patients who developed hepatopulmonary syndrome while on T-DM1Age, yrsSites of metastases# lines of prior txCycles of T-DM1Presenting sign or symptomsNon-contrast ECHO findingsSupplemental oxygenTransaminitis; hyperbilirubinemiaEvidence of portal hypertensionTelangiectasiasHgb prior to T-DM1Hgb end of txLung perfusion studyContrast ECHOPt 153LN, bone090DOE, hypoxemia, clubbingleft atrial enlargement (62 mg/m2)YesNovarices, splenomegalyNot documented12.9 g/dL10.7 g/dL13.5%Yes, small shuntPt 235LN, bone, liver751DOEleft atrial enlargement (54 mg/m2)YesGrade 1; Grade 2varices, splenomegaly; thrombocytopeniaYes, face and handsn/a11.9 g/dL24%Yes, large shuntPt 338LN, bone251Hyperbilirubinemiaborderline left atrial enlargementYesGrade 1; Grade 2varices, splenomegalyYes, trunk, extremities, face11.7 g/dL16.2 g/dL17.8%Yes, moderate shuntPt 448LN, liver186DOEleft atrial enlargement (49 mg/m2)NoGrade 1; Grade 2varices, splenomegalyYes, trunk12.5 g/dL16.1 g/dL7.9%Yes, large shunt Citation Format: Ally Higgins, Adham K Alkurashi, Patrick S Kamath, Vivek N Iyer, Ciara O'Sullivan, Tufia C Haddad. Hepatopulmonary syndrome with long term use of ado-trastuzumab emtansine (T-DM1) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-18-03.