SummaryBackground: Repeated hospital readmissions are frequent and increasing over time in patients with heart failure (HF). The predictors for readmission in patients with HF are not completely understood.Hypothesis: The study was undertaken to investigate the time course of readmission by specific cause in patients with HF, and to examine the independent effects of HF etiology and left ventricular (LV) function on cause-specific readmissions.Methods: A retrospective cohort of 493 consecutive patients with HF was followed for readmission for 16.5 ± 12.3 months. Ischemic etiology of HF was defined as history of myocardial infarction (MI), coronary artery bypass graft (CABG), percutaneous transluminal coronary angioplasty (PTCA), or ≥ 70% coronary stenosis. Left ventricular function was assessed echocardiographically. Cause-specific readmissions were classified as HF, cardiovascular disease (CVD) other than HF, and other non-CVD.Results: The annual readmission rate was 56.6%. Median time to readmission was 91 days, with 18.3% patients readmit-

TTP should be suspected in patients presenting with unexplained anemia and thrombocytopenia with an RDW > or = 18%.

Rituximab, an anti-CD20 monoclonal antibody used to treat B cell lymphoproliferative disorders and autoimmune diseases, kills cells through complement dependent cytotoxicity, antibody-dependent cellular toxicity and apoptosis. A mechanism of resistance to rituximab is upregulation of the complement regulatory proteins, CD59 and CD55. Paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic disorder caused by PIGA mutations that lead to a loss of all glycosylphospatidylinositol (GPI)-anchored proteins including, CD55 and CD59. We compared the cytotoxic activity of rituximab against a PNH B cell line, LD -, and the isogenic cell line LD - PIGA + in which GPI-anchor expression was restored by stable transfection of PIGA. The PNH cell line was more sensitive to rituximab-mediated killing than the LD - PIGA + cells. Biochemical disruption of GPI anchors with phosphatidylinositol specific phospholipase C (PIPLC), a phospholipase that cleaves GPI-anchored proteins, also increased rituximab-mediated killing. Thus, genetic and biochemical interruption of GPI anchor proteins augments sensitivity to rituximab.

9545 Background: Immune checkpoint inhibition (ICI) has improved outcomes for many treatment-naïve advanced non-small cell lung cancer (NSCLC) patients. However, better biomarkers are needed to predict patient response and guide treatment decisions considering added toxicity and higher cost of combination treatments. A prospectively designed, observational study assessed the ability of a clinically validated, blood-based, host immune classifier (HIC) to predict ICI therapy outcomes. Methods: The study (NCT03289780) includes 33 US sites having enrolled over 3,000 NSCLC patients at any stage and line of therapy. All enrolled patients are tested and designated HIC-Hot (HIC-H) or HIC-Cold (HIC-C) prior to therapy initiation. An interim analysis of secondary and exploratory endpoints was performed after 12- 18 months (mo) follow-up with the first 2,000 enrolled patients. We report the overall survival (OS) of HIC-defined subgroups comprising advanced stage (IIIB and higher) NSCLC patients treated with first-line regimens (284 ICI containing treatments, 877 total first-line patients). Results: In a real-world clinical setting, OS of advanced stage NSCLC treatment-naïve patients receiving platinum-based chemotherapy (n = 392) did not differ significantly from patients receiving any type of ICI containing regimen (n = 284); 11.7 mo vs. 14.4 mo; hazard ratio (HR) = 0.94 [95% confidence interval (CI): 0.76–1.17], p = 0.59. HIC-H patients experienced longer survival than HIC-C across multiple regimens, including ICI. For all ICI, median OS (mOS) was not reached for HIC-H (n = 196, CI: 15.4 mo–undefined) vs. 5.0 mo (n = 88, CI: 2.9 mo–6.4 mo) for HIC-C patients (HR = 0.38 [CI: 0.27–0.53], p < 0.0001). Similar results were seen in the ICI only (16.8 mo vs. 2.8 mo; n = 117, HR = 0.36 [CI: 0.22–0.58], p < 0.0001) and ICI/chemotherapy combination subgroups (unreached vs. 6.4 mo; n = 161, HR = 0.41 [CI: 0.26–0.67], p = 0.0003). In the PD-L1 high cohort (PD-L1 ≥50%), mOS for HIC-H was not reached (n = 81, CI: 13.9 mo–undefined) vs. 3.9 mo (n = 41, CI: 2.1 mo–7.8 mo) for HIC-C (HR: 0.39 [CI: 0.24-0.66], p = 0.0003). HIC results were independent of PD-L1 score (p = 0.81) and remained predictive of OS in first-line ICI-treated patients when adjusted for PD-L1 and other covariates by multivariate analysis (HR = 0.40 [CI: 0.28-0.58], p < 0.0001). Conclusions: Blood-based host immune profiling may provide clinically meaningful information for selecting NSCLC patients for two common ICI containing regimens independent of and complementary to PD-L1 score.