Abstract Body (Do not enter title and authors here): Polatuzumab Vedotin is a novel antibody-drug conjugate that targets CD79b, a B-cell antigen receptor expressed in mature B-cell lymphomas such as Diffuse Large B-Cell Lymphoma (DLBCL)¹. Yet, its effect on cardiac disease is unknown.

We present a case illustrating clinical outcome of a patient treated with Polatuzumab plus standard Rituximab, Vincristine and Prednisone (Pola-R-CHP) for metastatic DLBCL with profound cardiac involvement. She is a 56-year-old female who presented with pre-syncope associated with night sweats, myalgia and weight loss. On examination, a grade II/VI tricuspid regurgitation murmur was auscultated. CT showed chronic right lower lobe pulmonary embolism along with axillary and mediastinal lymphadenopathy. New findings of a mass protruding into the right atrium with thickening of right atrial and ventricular walls, a right atrial thrombus and small pericardial effusion were reported. Cardiac MRI characterized the mass to be partially vascularized with extension from right to left chambers encasing RCA and coronary sinus with diffuse interstitial expansion and inflammation (Image 1). Axillary lymph node biopsy was consistent with aggressive B cell lymphoma with positive CD19, CD20 and BCL2 markers. Hospital course was significant for polymorphic VT with degeneration into VFib arrest. ROSC was achieved after one round of ACLS. Multiple factors may have contributed to VT including myocardial inflammation, possible tumor induced RCA compression and prolonged QT. Amiodarone and anticoagulation were initiated and patient was discharged with a wearable cardiac defibrillator along with oncology and cardio-oncology referrals.

Traditionally, DLBCL is treated with R-CHOP (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, Prednisone), however up to 40% of patients develop refractory disease or have a relapse¹. As in the recent POLARIX trial¹, our patient underwent three cycles of novel regimen of Pola-R-CHP. Follow up PET showed dramatic response with metabolic remission (Image 3). Cardiac MRI showed reduction in RV tumor, RA thrombus and inflammatory burden with preserved LV and RV function (Image 2). No further arrhythmias were noted and the patient completed chemotherapy. This case highlights a positive outcome in a patient with aggressive DLBCL with cardiac metastasis treated with Polatuzumab based therapy.

References
1. Tilly H et al. Polatuzumab vedotin in previously untreated diffuse large B-Cell lymphoma. NEJM 2022;386:351–363