Citations

Introduction: HIV-associated diffuse large B-cell lymphoma (HIV-DLBCL) is a significant complication in HIV-positive individuals, presenting unique clinical challenges and a poorer prognosis compared to patients with de novo DLBCL. Epstein-Barr Virus (EBV) status is a critical factor influencing the pathogenesis, clinical behavior, and therapeutic responses in these lymphomas. Plasmablastic lymphomas (PBL) have shared some overlapping genomic abnormalities with HIV-DLBCL including MYC rearrangements. This study aims to elucidate the differences in the genetic profiles and pathway activations between EBV(+) and EBV(-) HIV-DLBCL through comprehensive genomic profiling. Methods: Cases of DLBCL were identified in patients living with HIV from a multi-institute cooperative group. Cases of Burkitt lymphoma and PBL were excluded. We performed whole exome sequencing (WES) on 106 tumors of HIV-DLBCL and RNA sequencing on 39 tumors and mapped the reads to hg38 reference genome using BWA and STAR, respectively. EBV status of cases was determined by in situ hybridization and/or reads mapped on EBV genome in sequencing data. Somatic mutations were identified using variant callers (Strelka2, Mutect2) with WES data. For those mutated genes in COSMIC, allele frequency cutoff was set at 0.03. Mutations with an artifact score larger than 0.7 in SOBDetector and those located in segmental duplications were further removed. They were annotated with Ensembl Variant Effect Predictor, manually checked, and plotted with maftools. RNAseq read counts aligned to each gene were obtained by featureCounts and DEseq2 was used for differential expression (DE) analysis between EBV positive and negative groups. Pathway analysis with the DE genes was performed using GSEA. FISH analysis was performed using MYC, BCL2, and BCL6 break-apart probes. Results: There were 41 cases of EBV(+) HIV-DLBCL and 65 cases of EBV(-) HIV-DLBCL. FISH of EBV(+) HIV-DLBCL identified 42% (3/7) with MYC rearrangement (MYCr), none with BCL2 rearrangements (BCL2r) (0/6), and 33% (2/6) positive for BCL6 rearrangement (BCL6r) with 1 tumor having a MYCr/BCL6r. For EBV(-) HIV-DLBCL, there were 35% with a MYCr (6/17), 18% with BCL2r (2/11), and 27% with a BCL6r (3/11) with 2 tumors with MYCr/BCL6r, and 1 tumor with MYCr/BCL2r/BCL6r. The most frequent mutations seen in EBV(+) HIV-DLBCL were STAT3 (32%), DDX3X (22%), and TP53 (15%). For EBV(-) HIV-DLBCL, the most frequent mutations were KMT2D (25%), TP53 (23%), GNA13 (22%), and TET2 (22%). Pathways that were most commonly associated with EBV(+) HIV-DLBCL were JAK/STAT (42%) (STAT3, JAK1) and NF-kB (39%)(DDX3X, TNFAIP3) while EBV(-) HIV-DLBCL was associated with epigenetic modifiers (62%)(KMT2D, TET2, EP300), JAK/STAT (45%)(SOCS1, JAK3) and PI3K/mTOR (40%)(GNA13, MTOR). Significant disparities between EBV(+) and EBV(-) were KMT2D (24% vs 50%, P=0.0025), TET2 (10% vs 26%, P=0.008), SOCS1 (29% vs 39%, P=0.04), DDX3X (15% vs 5%, P=0.03), and GNA13 (5% vs 24%, P=0.001). RAS mutations (KRAS, NRAS) were infrequent in HIV-DLBCL (EBV(+), 12%; EBV(-), 6%), in contrast to prior studies of PBL. Gene expression profiling showed enrichment of MYC targets, oxidative phosphorylation, and the mTORC pathway in EBV(+) as compared to EBV(-) HIV-DLBCL. Conclusion: EBV(+) HIV-DLBCL show a distinct mutational profile compared to EBV(-) HIV-DLBCL, with EBV(+) cases showing frequent mutations with STAT3 and DDX3X in contrast to EBV(-) cases with frequent mutations associated with epigenetic modification pathways (KMT2D, TET2). These genetic profiles underscore the need for tailored therapeutic approaches depending on EBV status. Although the analysis is limited and requires confirmation in a larger cohort, this is the largest study at present evaluating these tumors.

Introduction Peripheral T-cell lymphoma (PTCL) encompasses a heterogeneous group of clinically aggressive entities. ~30% of cases cannot be further classified and are designated as PTCL - not otherwise specified (NOS). We delineated two novel molecular subgroups among PTCL-NOS with distinct clinical and biological features: PTCL-GATA3 which is characterized by high expression of GATA3, a master regulator of T-helper-2-cell (TH2) differentiation, and its target genes (i.e., CCR4, IL4, IL13) and PTCL-TBX21 which is characterized by high expression of TBX21, a master regulator of TH1 differentiation, and its target genes (i.e., CXCR3, IFNG), with the GATA3 subtype showing significantly worse clinical outcomes (overall survival). Nonsense mutations in CCR4 are found predominately in PTCL-GATA3, often within the cytoplasmic domain and gain-of-function in nature. Methods Mutation and copy number data were generated from whole exome sequencing (TFH phenotype excluded following LLMPP pathology review; n = 153). Single nucleotide variants were determined using Mutect2 and Varsvan2 using in-house filtering. Copy number (CN) profiles were generated using CNVkit. Four CCR4 cytoplasmic domain mutants and controls (cytoplasmic domain knockout [CDKO], wild-type CCR4 overexpression (CCR4-WT), and empty vector [EV]) were transduced into healthy-donor CD4+ T cells (n = 2). Polarization studies were generated using TH1- or TH2-associated cytokine exposure. Surface plasmon resonance was used to determine the binding affinity of CCR4 proteins to CCL17 and CCL22. In silico docking studies were done through Schrödinger's BioLuminate. Antibody-dependent cell-mediated cytotoxicity (ADCC) assay was performed through co-incubation of NK92 (CD16 and CD56) and CCR4 edited primary CD4+ T-cells (stained with calcein AM) for 2 hours at a 5:1 NK:T cell ratio by 7-AAD flow cytometry. Results PTCL-GATA3 had a higher frequency of CN aberrations (e.g. TP53, PTEN CN loss) and a more aberrant genome (p < 0.001) than PTCL-TBX21, including mutations with genes associated with DNA repair and damage (TP53, ATM) and T-cell differentiation (CCR4). CCR4 mutations were virtually mutually exclusive with TP53 mutations, and these cases showed higher CCR4 mRNA and protein expression than CCR4-WT cases (p < 0.05). Primary CD4+ T-cells with ectopic expression of the CCR4 variants, especially CCR4-Q330X, did not require CD3/CD28 for proliferation, bypassing CD3/CD28 ligation for T-cell activation. In addition, proliferation rates were similar between TH2-conditional media and normal media, but proliferation and TBX21 expression in TH1-conditional media were inhibited, implying a novel role of CCR4 in T-cell receptor (TCR) activation and TH-differentiation. CCR4 variant proteins showed higher binding affinity for their natural ligands, CCL22 and CCL17, with mutants exhibiting tighter binding to both ligands (1.5- to 3-fold decrease in KD) by surface plasmon resonance and in silico modeling studies. The in silico models demonstrated mutant CCR4 bound mogamulizumab tighter than CCR4-WT, consistent with a higher ADCC-induced apoptosis rate, highest with CCR4-Q330X mutation. CCR4-Y331X exhibited a worse docking score compared to CCR4-WT and a lower ADCC-induced apoptosis rate. Conclusions Our findings reveal distinct genetic characterizations including aberrant TP53 and PI3K signaling and CCR4 mutations in PTCL-GATA3. These CCR4 mutations are shown to have a key role in PTCL-GATA3 pathogenesis by dysregulating TH-differentiation and aberrantly activating the TCR. CCR4 mutation promotes the TH2 phenotype by blocking TH1 differentiation. CCR4 mutant proteins demonstrated an increased binding affinity towards its known ligands, CCL17 and CCL22, and mogamulizumab, consistent with previous studies exhibiting mogamulizumab efficacy against CCR4 mutations. However, the most frequent CCR4 mutant, Y331X, showed worse binding compared to other CCR4 mutants or CCR4-WT, a mutation that showed Mogamulizumab-resistance in a prior CTCL study as well as in an in vitro ADCC assay. The results emphasize aberrant pathways implicated by genomic and clinical evaluation of two novel PTCL subtypes, as well as support the novel role of mutant CCR4 in enhancing T-cell lymphomagenesis and T-helper differentiation, highlighting multiple therapeutic targets.

Introduction Plasmablastic lymphoma (PBL) is a rare aggressive subtype of lymphoma. It is more common in HIV positive patients, and is often associated with Epstein-Barr virus (EBV) and MYC rearrangements. PBL is characterized by markers of plasmacytic differentiation including CD138 and MUM1/IRF4, and loss of B-cell markers such as CD20, which suggests a cell of origin similar to that of multiple myeloma (MM) or activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL). The standard of care for PBL is CHOP-based chemotherapy but this is frequently not curative. Other than EBV-negative status, which defines a high-risk group, no other biological features have been discovered that are associated with outcomes. Methods Here, we provide a comprehensive analysis of the genomic and transcriptomic landscape of PBL using a collection of 176 exomes and genomes (n=55 new, contributed by Lymphoma/Leukemia Molecular Profiling Project [LLMPP] sites and centrally reviewed by the LLMPP pathology panel [WHO 2016]; n=121 previously published [PMID: 33225311, 33951889, 34465776, 34714908]), 65 transcriptomes (n=44 new; n=21 published) and 37 in situ single cell transcriptomic profiles (CosMx Spatial Molecular Imager) from archival diagnostic tissue biopsies. Somatic mutations (SNVs/Indels) were identified using an ensemble of four variant callers (Strelka2, Lofreq, Mutect2, SAGE). Salmon and DESeq2 were used to identify differentially expressed genes. This multi-omics dataset was compared to other known B-cell malignancies including 92 MM, 238 Burkitt lymphomas (BL), and 208 DLBCLs. Cell segmentation of the CosMx data was performed using Baysor and downstream analyses were conducted using the Seurat workflow. For functional validation, cell viability assays (CellTiter-Glo Luminescent Assay) were conducted in the PBL cell line, PBL-1, and 4 control DLBCL cell lines. Results Within the cohort, 63% (106/169) of primary PBL cases were EBV-positive (EBV+) and 57% (82/144) harbored MYC rearrangements (MYC+). When stratifying patients by EBV and MYC rearrangement status, mutations in different genes were enriched in each group: STAT3 occurred in 55% (29/53) of EBV+/MYC+ PBLs; NOTCH1 in 19% (7/36) of EBV+/MYC-; MYC in 24% (6/25) and TP53 in 40% (10/25) of EBV-/MYC+ tumors; TET2 was mutated in 38% (9/24) and KRAS in 25% (6/24) of EBV-/MYC- PBLs. EBV-/MYC+ tumors represented a subgroup of patients with dismal outcomes. The 2-year overall survival (OS) of these patients was 22% compared to 61%, 78%, and 54% of EBV+/MYC+, EBV+/MYC-, and EBV-/MYC- PBL patients, respectively (log-rank test p-adj. < 0.05). Consistent with previous studies, we observed recurrent mutations affecting JAK-STAT (STAT3, SOCS1, SOCS3, DUSP2) in 41% of cases and RAS-RAF (NRAS, KRAS, BRAF) signaling in 38% of all PBLs. In contrast to ABC-DLBCL, very few mutations occurred in the NF-κB signalling pathway. Accordingly, PBL showed marked downregulation of genes involved in B-cell receptor and NF-κB signaling. Consistent with the lack of reliance on these pathways, functional analyses in PBL-1 showed resistance to treatment to ibrutinib as well as PI3K- and MALT1-inhibitors. Moreover, constitutive expression of the IκBα super-repressor did not affect viability of PBL-1 cells. In situ single cell transcriptomic data analyses showed a sparse tumor microenvironment (TME) in PBL, with the primary non-malignant cell types being, on average, 10% macrophages, 7% NK/T cells, and 4% stromal cells of all represented cell types. EBV+/MYC+ tumors displayed a more abundant immune cell population with higher levels of macrophages (median 12%) and NK/T cells (median 9%), whereas EBV-/MYC- tumors were composed of the lowest levels of immune cells (median 4% macrophages and 1% NK/T cells). With respect to malignant cell phenotypes, we noted a novel population of SPP1-expressing cells that were enriched in EBV+/MYC+ tumors and a population of CD44-expressing cells that were enriched in EBV+/MYC- tumors. Conclusion Here we present novel subgroups of PBL with unique biology and clinical outcomes. We show that PBL does not rely on B-cell receptor signaling, instead relying on potentially targetable vulnerabilities in JAK-STAT, NOTCH, and RAS-RAF signaling according to EBV positivity and MYC rearrangement status. Lastly, we provide insight into the TME of PBL and demonstrate a novel population of SPP1 and CD44 expressing malignant cells in EBV+ tumors.

Background: The Phase 1/2 ECOG-ACRIN sponsored intergroup trial E4412 (NCT01896999) investigated brentuximab vedotin (BV) combined with the checkpoint inhibitors nivolumab (N) and ipilimumab (I) in patients with relapsed or refractory classic Hodgkin lymphoma (R/R HL). Here we present the safety and efficacy results for the cohort of pediatric patients aged 12-17 years. Methods: Patients were randomly assigned to treatment with the doublet of BV/N or triplet of BV/N/I, with the following dosing: BV 1.8mg/kg every 21 days for up to 16 cycles; Nivolumab 3mg/mg every 21 days for up to 34 cycles; Ipilimumab 1mg/kg every 9 weeks for up to 9 doses. Response evaluation by PET/CT was performed after 4 cycles. Transplant-eligible patients with CR could discontinue protocol therapy to receive a consolidative autologous stem cell transplant (ASCT). Results: Sixteen pediatric patients with a median age of 16 (range 12-17) were randomized. 75% of patients had received only 1 prior line of treatment with none having previously received BV and only 1 patient with prior ASCT. All patients were treated (8 in each arm) and included in the pediatric safety analysis cohort receiving at least one cycle of therapy. There were four reported grade (gr) 3 or greater toxicities: lymphopenia (gr 3) and neutropenia (gr 3) on the BV/N arm; and neutropenia (gr 4) and rash (gr 3) on the BV/N/I arm. Rash of any grade was more common in patients treated with BV/N/I (n=6) compared to BV/N (n=1). Peripheral sensory neuropathy was reported in 2 patients (BV/N, gr 2, n=2) There were no grade 5 toxicities. Fourteen patients (7 in each arm) were evaluable for response. The CR rate on both the BV/N and BV/N/I arms was 100%. The median survival follow up was 23.7 months (15.7 - 31.7). The 24-month PFS was 57% for BV/N and 100% for BV/N/I. Six patients (2 BV/N; 4 BV/N/I) discontinued protocol therapy to receive a consolidative ASCT. The 24-month PFS for patients consolidated with an ASCT was 100%, with all events occurring in patients randomized to BV/N, but not receiving an ASCT. Conclusion: Pediatric patients receiving both BV/N and BV/N/I had 100% CR rate with limited toxicity. Although this is a small cohort, there have been no progression events observed in patients treated with BV/N/I, including 3 patients treated without a consolidative ASCT.

AbstractBackground and purposeLower left atrial (LA) function is associated with higher dementia risk and may be mechanistically linked through vascular brain injury, an established correlate for higher dementia risk. Using data from the Atherosclerosis Risk in Communities study, we assessed the cross‐sectional association between LA function and brain magnetic resonance imaging (MRI) markers of vascular brain injury.MethodsWe included 1488 participants who were free of prevalent dementia, stroke, or atrial fibrillation and who underwent a two‐dimensional echocardiogram and brain MRI in 2011–2013 (mean [± standard deviation] age 76 [± 5] years, 60% female, 27% Black). LA function measures (reservoir, conduit, contractile strain) were assessed in quartiles. Brain MRI measures included cerebral microbleeds, brain infarcts, and white matter hyperintensity (WMH) volume. Logistic regression was used for dichotomous outcomes. Linear regression was used for WMH volume.ResultsOverall, 343 (23%) and 344 participants (23%) had ≥1 cerebral microbleed or brain infarct. After multivariable adjustments, the lowest LA reservoir and conduit strain quartiles (vs. highest quartile) were associated with higher odds of the presence of ≥1 cerebral microbleed (odds ratios [95% confidence intervals] 1.78 [1.42–2.22] and 1.52 [1.22–1.90]). Compared to the highest quartile, participants in the lowest LA conduit strain quartile had 1.51 (95% confidence interval 1.22–1.88) times higher odds of having ≥1 brain infarct. Lower LA contractile strain was associated with lower odds of brain infarcts. No association with WMH volume was noted.ConclusionsWe found that LA reservoir and conduit strain were associated with cerebral microbleeds and brain infarcts. Lower LA function may be linked to dementia risk via vascular brain injury. Prospective studies are needed to confirm these findings.

Abstract Background NT-proBNP levels are associated with disease severity and outcomes in patients with HF across the spectrum of LVEF. Recently, it has been suggested that the effectiveness of certain treatments may vary by NT-proBNP level with greater benefit from omecamtiv mecarbil, and smaller benefit from vericiguat, in patients with higher NT-proBNP levels. We examined the benefit of sacubitril/valsartan on outcomes across the range of NT-proBNP levels in patients with HFrEF/HFmrEF/HFpEF. Purpose To evaluate clinical outcomes, and the efficacy of sacubitril/valsartan, according to NT-proBNP levels, in patients with HFrEF/HFmrEF/HFpEF, using the pooled dataset of participants in the PARADIGM-HF and PARAGON-HF trials. Methods The PARADIGM-HF (n=8399) and PARAGON-HF (n=4822) trials enrolled patients with HF, functional limitation, and elevated NT-proBNP levels. Patients with LVEF ≤40% were randomized to sacubitril/valsartan 200 mg twice daily or enalapril 10mg twice daily in PARADIGM-HF, and those with LVEF ≥45% to sacubitril/valsartan 200 mg twice daily or valsartan 160mg twice daily in PARAGON-HF. Patients were categorized by quintiles of NT-proBNP level and using NT-proBNP as a continuous variable, analysed using restricted cubic splines. The primary outcome in the present study was the composite of cardiovascular death or HF hospitalization. Results Among the 13195 patients in the pooled PARADIGM-HF and PARAGON-HF dataset, 13142 (99.6%) patients with baseline NT-proBNP were analysed. Patients with higher NT-proBNP levels were more often male, had lower body mass index and LVEF, worse New York Heart Association functional class, worse kidney function, and more atrial fibrillation, while age was similar across NT-proBNP levels. The rate of the primary outcome (per 100 person-years) increased with NT-proBNP level: quintile 1, 5.9 (95%CI 5.3-6.5); quintile 2, 7.5 (95%CI 6.9-8.2); quintile 3, 9.0 (95%CI 8.2-9.7); quintile 4, 12.0 (95%CI 11.1-12.9); and quintile 5, 20.8 (95%CI 19.6-22.2) (Figure 1). Similar trends were observed for other outcomes. The benefit of sacubitril/valsartan was consistent across NT-proBNP levels: the hazard ratio for the primary outcome in NT-proBNP quintile 1 was 0.79 (95%CI 0.65-0.96); quintile 2, 0.87 (95%CI 0.72-1.04); quintile 3, 0.79 (95%CI 0.66-0.93); quintile 4, 0.85 (95%CI 0.73-0.99); and quintile 5, 0.86 (95%CI 0.76-0.97), P-interaction=0.86. The consistent benefit of sacubitril/valsartan was also seen when NT-proBNP was analysed as a continuous variable (Figure 2). The absolute benefit was greatest in quintile 5 of NT-proBNP; the number needed to treat for quintile 5 was 16 versus 37 for the quintile 1 for the primary endpoint. Conclusions Patients with higher NT-proBNP had worse outcomes, but the benefits of sacubitril valsartan were consistent across the range of NT-proBNP levels of participants in PARADIGM-HF and PARAGON-HF.Kaplan-Meier curvesEffect of sac/val across NT-proBNP range

Abstract Background Concerns have been raised about the appropriateness of use and safety of beta-blockers (BBs) in patients with heart failure and mildly reduced (HFmrEF) and preserved ejection fraction (HFpEF). However, randomized trial evidence is still lacking. Purpose To perform an observational analysis of the association between BB use and clinical outcomes in a large dataset of patients with HFmrEF and HFpEF. Methods We pooled individual patient data from four large HFmrEF/HFpEF trials (I-Preserve, TOPCAT, PARAGON-HF, and DELIVER). The associations between baseline BB use and outcomes were analyzed. The primary outcome was the composite of cardiovascular death or HF hospitalization. Results Among the 16,951 patients included, the mean left ventricular ejection fraction (LVEF) was 56.8%, and 13,400 (79.1%) had HFpEF (LVEF ≥50%). Overall, 12,812 patients (75.6%) received a BB. The median bisoprolol-equivalent dose of BB was 5.0 (Q1-Q3: 2.5-5.0) mg with BB continuation rates of 95.1% at 1 year and 93.1% at 2 years (in patients who survived more than 1 and 2 years, respectively). Overall, the hazard ratio (HR) for the primary outcome did not differ between BB users and non-users (HR: 0.98 [95% CI: 0.91-1.05]) but among patients with HFmrEF, BB users had a lower HR (0.84 [95% CI 0.71-0.98]), whereas in HFpEF the HR was similar BB users and non-users (0.99 [95% CI 0.92-1.08]). However, after comprehensive adjustment for known prognostic variables, including NT-proBNP, BB use was associated with a better outcome in the overall cohort (HR 0.81 [0.74-0.88]), and this association was maintained across the range of LVEF (Figure 1). In subgroup analyses, the risk of the primary outcome was similar in BB users and non-users with or without a history of myocardial infarction, with or without a history of hypertension, or with or without a baseline heart rate <70 bpm. By contrast, a better outcome with BB use was seen in patients with atrial fibrillation compared to those without atrial fibrillation (Figure 2). Conclusions Although this is an observational analysis of non-randomized treatment, there was no suggestion that BB use was associated with worse HF outcomes even after extensive adjustment for other prognostic variables. Figure Legends Figure 1. Association between beta-blocker use and outcomes across the range of LVEF. Risk in beta-blocker users versus non-users is shown as an adjusted continuous hazard ratio Figure 2. Association between beta-blocker use and non-use in the overall population and clinically relevant patient subgroups, shown as an adjusted hazard ratio (HR). The outcome analyzed was the composite of CV death or HF hospitalization (primary outcome)Figure 1Figure 2

BACKGROUND: Cognitive impairment is common in patients with heart failure and preserved ejection fraction but its clinical correlates and prognostic associations are poorly understood. METHODS: We analyzed cognitive function, using the Mini-Mental State Examination (MMSE), in patients with heart failure and preserved ejection fraction enrolled in a prespecified substudy of the PARAGON-HF trial (Prospective Comparison of Angiotensin Receptor Neprilysin Inhibitor With Angiotensin Receptor Blocker Global Outcomes in Heart Failure With Preserved Ejection Fraction). Logistic regression analyses were performed to determine the variables associated with lower MMSE scores at baseline and postbaseline decline in MMSE scores at 48 weeks. Cox proportional hazards regression and semiparametric proportional rates models were used to examine the risk of clinical outcomes related to baseline MMSE scores, and decline in MMSE scores during follow-up, adjusted for prognostic variables including NT-proBNP (N-terminal pro-B-type natriuretic peptide). RESULTS: At baseline, cognitive function was normal (MMSE score 28–30) in 1809 of 2895 patients (62.5%), borderline (score 24–27) in 794 (27.4%), and impaired (score <24) in 292 (10.1%). Variables associated with both a lower MMSE score at baseline and a decline in score from baseline included older age, a history of stroke or transient ischemic attack, and lower serum albumin. Compared with those with baseline MMSE scores of 28 to 30, patients in the lower MMSE score categories had a stepwise increase in the risk of the composite of time to first heart failure hospitalization or cardiovascular death, with an adjusted hazard ratio of 1.27 (95% CI, 1.06–1.53) for those with scores of 24 to 27 and 1.58 (95% CI, 1.21–2.06) for those with scores <24, respectively. These associations were also found for the individual components of the composite and all-cause death. Likewise, cognitive impairment was associated with a 50% higher risk of total (first and repeat) heart failure hospitalizations and cardiovascular deaths. Examining the change in MMSE score from baseline, a decrease in MMSE score during follow-up was associated with a higher risk of death. CONCLUSIONS: In patients with heart failure and preserved ejection fraction, even modest baseline impairment of cognitive function was associated with worse outcomes, including death. A decline in MMSE score during follow-up was a strong predictor of mortality, independent of other prognostic variables.

Background Prognostic markers and biological pathways linked to detrimental clinical outcomes in heart failure with preserved ejection fraction (HFpEF) remain incompletely defined. Methods and Results We measured serum levels of 4123 unique proteins in 1117 patients with HFpEF enrolled in the PARAGON‐HF (Efficacy and Safety of LCZ696 Compared to Valsartan, on Morbidity and Mortality in Heart Failure Patients With Preserved Ejection Fraction) trial using a modified aptamer proteomic assay. Baseline circulating protein concentrations significantly associated with the primary end point and the timing and occurrence of total heart failure hospitalization and cardiovascular death were identified by recurrent events regression, accounting for multiple testing, adjusted for age, sex, treatment, and anticoagulant use, and compared with published analyses in 2515 patients with heart failure with reduced ejection fraction from the PARADIGM‐HF (Prospective Comparison of ARNI With ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) and ATMOSPHERE (Efficacy and Safety of Aliskiren and Aliskiren/Enalapril Combination on Morbidity–Mortality in Patients With Chronic Heart Failure) clinical trials. We identified 288 proteins that were robustly associated with the risk of heart failure hospitalization and cardiovascular death in patients with HFpEF. The baseline proteins most strongly related to outcomes included B2M (β‐2 microglobulin), TIMP1 (tissue inhibitor of matrix metalloproteinase 1), SERPINA4 (serpin family A member 4), and SVEP1 (sushi, von Willebrand factor type A, EGF, and pentraxin domain containing 1). Overall, the protein–outcome associations in patients with HFpEF did not markedly differ as compared with patients with heart failure with reduced ejection fraction. A proteomic risk score derived in patients with HFpEF was not superior to a previous proteomic score derived in heart failure with reduced ejection fraction nor to clinical risk factors, NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), or high‐sensitivity cardiac troponin. Conclusions Numerous serum proteins linked to metabolic, coagulation, and extracellular matrix regulatory pathways were associated with worse HFpEF prognosis in the PARAGON‐HF proteomic substudy. Our results demonstrate substantial similarities among serum proteomic risk markers for heart failure hospitalization and cardiovascular death when comparing clinical trial participants with heart failure across the ejection fraction spectrum. Registration URL: https://www.clinicaltrials.gov ; Unique Identifiers: NCT01920711, NCT01035255, NCT00853658.