Pembrolizumab Added to Ifosfamide, Carboplatin, and Etoposide Chemotherapy for Relapsed or Refractory Classic Hodgkin Lymphoma: A Multi-institutional Phase 2 Investigator-Initiated Nonrandomized Clinical Trial.

Importance: To our knowledge, this is the first clinical trial designed to investigate concurrent treatment with a checkpoint inhibitor and conventional chemotherapy in relapsed or refractory classic Hodgkin lymphoma in patients destined for an autologous stem cell transplant. Objective: To evaluate the complete response rate as assessed by 18F-fluorodeoxyglucose-positron emission tomography with computed tomography (FDG-PET/CT) after salvage therapy for patients with relapsed or refractory classic Hodgkin lymphoma. Design, Setting, and Participants: A single-group, phase 2, multi-institutional nonrandomized clinical trial to evaluate the addition of pembrolizumab to ifosfamide, carboplatin, and etoposide (ICE) chemotherapy was conducted from April 20, 2017, to October 29, 2020, at 5 US sites. The 42 patients were aged 18 years or older, with an Eastern Cooperative Oncology Group Performance Status Scale score of 0 or 1 and biopsy-proven relapsed or refractory classic Hodgkin lymphoma after 1 or 2 prior lines of chemotherapy. Patients were required to be appropriate candidates for transplant, with measurable lesions detected by FDG-PET/CT. Interventions: Two cycles of pembrolizumab (200 mg intravenously on day 1) with ICE chemotherapy every 21 days, followed by stem cell mobilization and collection, and then 1 cycle of pembrolizumab monotherapy followed by FDG-PET/CT response assessment. Main Outcomes and Measures: The primary end point was complete response rate detected by FDG-PET/CT, defined as a Deauville score of 3 or lower. Patients with a complete response proceeded to an autologous stem cell transplant. Secondary end points included progression-free survival, overall survival, stem cell mobilization, and neutrophil and platelet engraftment. Adverse events were monitored to assess safety. Results: Forty-two patients were enrolled, with 37 evaluable for the primary end point. The median age was 34 years (range, 19-70 years), 25 patients were female (68%), 6 were African American (16%), and 26 were White (70%). The complete response rate for the 37 patients assessed by FDG-PET/CT imaging was 86.5% (95% CI, 71.2%-95.5%); the overall response rate was 97.3% (36 patients), with 10.8% partial responses (4 patients). New areas of FDG-PET positivity in 2 patients were biopsied, showing noncaseating granuloma in 1 case and a reactive lymph node in a second. Progression-free survival and overall survival 2-year estimates were 87.2% (32 patients; 95% CI, 77.3%-98.3%) and 95.1% (95% CI, 88.8%-100%), respectively. The addition of pembrolizumab to ICE chemotherapy did not negatively affect stem cell mobilization or collection or engraftment, similar to prior experience in this patient population and setting. Conclusions and Relevance: Results suggest that the addition of pembrolizumab to ICE chemotherapy was well tolerated and highly effective in comparison with prior reports of chemotherapy-only regimens, supporting further investigation in patients with relapsed or refractory classic Hodgkin lymphoma eligible for an autologous stem cell transplant. Trial Registration: ClinicalTrials.gov Identifier: NCT03077828.

Indomethacin-induced oxidative stress enhances death receptor 5 signaling and sensitizes tumor cells to adoptive T-cell therapy.

BACKGROUND: Adoptive cell therapy (ACT) using genetically modified T cells has evolved into a promising treatment option for patients with cancer. However, even for the best-studied and clinically validated CD19-targeted chimeric antigen receptor (CAR) T-cell therapy, many patients face the challenge of lack of response or occurrence of relapse. There is increasing need to improve the efficacy of ACT so that durable, curative outcomes can be achieved in a broad patient population. METHODS: Here, we investigated the impact of indomethacin (indo), a non-steroidal anti-inflammatory drug (NSAID), on the efficacy of ACT in multiple preclinical models. Mice with established B-cell lymphoma received various combinations of preconditioning chemotherapy, infusion of suboptimal dose of tumor-reactive T cells, and indo administration. Donor T cells used in the ACT models included CD4+ T cells expressing a tumor-specific T cell receptor (TCR) and T cells engineered to express CD19CAR. Mice were monitored for tumor growth and survival. The effects of indo on donor T cell phenotype and function were evaluated. The molecular mechanisms by which indo may influence the outcome of ACT were investigated. RESULTS: ACT coupled with indo administration led to improved tumor growth control and prolonged mouse survival. Indo did not affect the activation status and tumor infiltration of the donor T cells. Moreover, the beneficial effect of indo in ACT did not rely on its inhibitory effect on the immunosuppressive cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2) axis. Instead, indo-induced oxidative stress boosted the expression of death receptor 5 (DR5) in tumor cells, rendering them susceptible to donor T cells expressing TNF-related apoptosis-inducing ligand (TRAIL). Furthermore, the ACT-potentiating effect of indo was diminished against DR5-deficient tumors, but was amplified by donor T cells engineered to overexpress TRAIL. CONCLUSION: Our results demonstrate that the pro-oxidative property of indo can be exploited to enhance death receptor signaling in cancer cells, providing rationale for combining indo with genetically modified T cells to intensify tumor cell killing through the TRAIL-DR5 axis. These findings implicate indo administration, and potentially similar use of other NSAIDs, as a readily applicable and cost-effective approach to augment the efficacy of ACT.

Phase 1/2 study of intratumoral G100 (TLR4 agonist) with or without pembrolizumab in follicular lymphoma.

Intratumoral injection of G100, a toll-like receptor 4 (TLR4) agonist, was shown pre-clinically to stimulate anti-tumor immune responses and tumor regression. This open-label, multicenter, phase 1/2 trial evaluated the safety, tolerability, and preliminary efficacy of intratumoral G100 injections following localized low-dose radiation in patients with follicular lymphoma (ClinicalTrials.gov #NCT02501473). The study was comprised of a G100 dose escalation (5 or 10 µg/dose, or 20 µg/dose for large tumors); a randomized component comparing G100 to G100 plus pembrolizumab; and G100 20 µg/dose expansion. Adverse events grade ≥3 were uncommon in patients treated with G100, and no unexpected toxicities were observed when combined with pembrolizumab. G100 20 µg (n = 18) resulted in an overall response rate of 33.3% and abscopal tumor regression in 72.2% of patients. This early-phase study provides a foundation for combining an intratumoral TLR4 agonist with agents to produce immune-mediated responses in follicular lymphoma with limited added toxicity.

Update on the role of copanlisib in hematologic malignancies.

Clinical research in hematologic malignancies is continually advancing with emerging concepts in therapy and evolving results from clinical protocols. Targeting of the PI3K pathway remains a valuable treatment across both hematologic and solid malignancies. There are currently four United States Food and Drug Administration (FDA)-approved PI3K inhibitors, with several others in development. Copanlisib is a pan-PI3K inhibitor currently FDA-approved for the treatment of relapsed/refractory follicular lymphoma (FL) following two lines of therapy. Since FDA approval, there have been further investigations into the long-term safety profile of copanlisib, as well as treatment of FL and other lymphoma subtypes, both indolent and aggressive. Here, we review the most recent available data from clinical trials, describe the management of the most common side effects, and explore future concepts. The use of copanlisib as part of a combination therapy for various hematologic malignancies will also be discussed. Copanlisib is a unique drug compared with other PI3K inhibitors, with remarkable potential to improve our armamentarium in cancer treatment.

Leukaemic relapse of anaplastic large cell lymphoma, ALK negative.

Anaplastic large cell lymphoma (ALCL), ALK negative (ALK-) is an aggressive lymphoproliferative disorder of mature T lymphocytes characterised by hallmark cells, CD30 positivity and lacking ALK protein expression. ALCL, ALK- has to be differentiated from peripheral T-cell lymphoma-not otherwise specified and classical Hodgkin's lymphoma. ALK- anaplastic large cell leukaemia should be considered in a patient with a history of ALCL, ALK- presenting with new leukaemia. We report a rare presentation of relapsed ALCL, ALK- with leukaemia after autologous stem cell transplantation in a 57-year-old male. Leukaemia, either as primary presentation or secondary transformation confers worse prognosis in ALCL, ALK- with very few cases reported so far. Emergency resuscitation with leukapheresis and treatment of tumour lysis syndrome along with supportive care should be followed by combination chemotherapy. Brentuximab vedotin and stem cell transplantation are the backbone of treatment for relapsed/refractory disease.

Assessing the impact of adding acetazolamide to oral or intravenous sodium bicarbonate as compared with intravenous bicarbonate monotherapy as urinary alkalinization in adults receiving high-dose methotrexate.

PURPOSE: High-dose methotrexate (HD-MTX) requires urine alkalinization to pH ≥ 7 for adequate excretion to prevent toxicity. Due to shortages of IV sodium bicarbonate (IV-NaHCO3), few reports have demonstrated utility of oral bicarbonate (PO-NaHCO3); however, the addition of acetazolamide (Acet) has not been well described. Our study compares outcomes between alkalinization methods of IV-NaHCO3 monotherapy versus IV-NaHCO2 + Acet and PO-NaHCO3 + Acet. METHODS: A single-center, IRB exempt, retrospective review was conducted from Jan 2016 to Sept 2019 of adults receiving HD-MTX ≥ 500 mg/m2. The primary outcome was time from start of alkalinization to pH ≥ 7. Secondary outcomes included time from start of alkalinization to initiation of HD-MTX, time to MTX clearance, length of stay (LOS), percentage of urine pH assessments < 7, and incidence of MTX toxicity. Statistical analysis was performed using SAS9.4 with alpha 0.05. RESULTS: Overall demographics (n = 196 HD-MTX cycles for 55 patients) include a mean age 55 years, HD-MTX dose ~ 5400 mg/m2, and 69% with a diagnosis of lymphoma. Adjusting for baseline demographic differences among groups, median time from first dose alkalinization to pH ≥ 7 and to start of HD-MTX was longer for those receiving IV-NaHCO3 (n = 41) vs either IV-NaHCO3 + Acet (n = 70) or PO-NaHCO3 + Acet (n = 76) (p = 0.0001). HD-MTX clearance to a level < 0.1 µmol/L was not improved with the addition of Acet. No difference existed among groups for pH results < 7, LOS, or incidence of MTX toxicity (p > 0.05). CONCLUSIONS: Addition of Acet to NaHCO3 reduces time to pH ≥ 7 and initiation of HD-MTX but does not appear to improve LOS, MTX toxicities, or time to MTX clearance.

The Monocytes That Repopulate in Mice After Cyclophosphamide Treatment Acquire a Neutrophil Precursor Gene Signature and Immunosuppressive Activity.

Cyclophosphamide (CTX) is a major component of the chemotherapy conditioning regimens used in the clinic to prepare cancer patients for hematopoietic stem cell transplantation or adoptive T cell therapy. Previous studies have shown that CTX given at nonmyeloablative doses in mice and patients leads to expansion of myeloid cells within which the monocytic subset exhibits immunosuppressive activity. However, the ontogeny and gene expression signature of these CTX-induced monocytes are not well-defined. Here, we report that the expansion of myeloid cells is a default process intrinsic to hematopoietic recovery after chemotherapy. During this process, the monocytes repopulated in mice acquire immunosuppressive activity, which can persist long after cessation of chemotherapy. Moreover, monocytes acquire a gene signature characteristic of neutrophil precursors, marked by increased proliferative capability and elevated expressions of multiple primary and secondary granules. We provide evidence that CTX-induced myeloid cell expansion is regulated by DNA methyltransferase 1 (Dnmt1) and dependent on chemotherapy-induced microbial translocation. These findings help advance our understanding of the differentiation, heterogeneity, and function of myeloid cells repopulating after chemotherapy.

A 43-Year-Old Woman With Hoarseness of Voice and Chest Pressure.

CASE PRESENTATION: A 43-year-old woman with a medical history of cervical cancer treated with curative hysterectomy 12 years earlier developed progressive dyspnea, chest discomfort, and hoarse voice over a 7-month period. The patient never smoked and had no exposure history. Imaging at an outside hospital showed a mediastinal mass with hilar adenopathy (Fig 1A), which was biopsied via endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) and revealed noncaseating granulomas with surrounding rims of lymphocytes (Fig 1B). The patient was given the diagnosis of sarcoidosis and started on prednisone 60 mg daily. She had no improvement in symptoms after 3 months of therapy and therefore presented for a second opinion.

Tumefactive fibroinflammatory lesion successfully treated with Rituximab.

Skull base pseudotumors, or tumefactive fibroinflammatory lesions (TFIL), are tumors characterized by local destruction with benign histopathology. Treatment includes surgery and steroids with varying degrees of symptom relief. A 45-year-old female presented with right otorrhea and middle ear effusion, which progressed to CN V3 pain/numbness, trismus, headache, and autophony. MRI showed a diffuse infiltrating mass in the right infratemporal region involving the trigeminal ganglion. Biopsy revealed benign fibromuscular and adipose tissue with lymphoplasmacytic infiltrate, giving a diagnosis of TFIL. Resection would be very difficult given tumor location. Initial treatment included an extended course of steroids without response, and interval disease progression. Two courses of rituximab 375 mg/m2 weekly × 4 given 3 months apart were then completed with excellent tolerance. With sixteen months following induction, the patient reports minimal symptoms with radiographic findings confirming continued disease regression. Rituximab is a potential treatment option for patients with TFIL without response to steroids.

Spotlight on copanlisib and its potential in the treatment of relapsed/refractory follicular lymphoma: evidence to date.

The importance of the phosphatidylinositol-3-kinase (PI3K) pathway in cell survival and proliferation has made it an attractive target in cancer therapy. The development of small molecule inhibitors for the PI3K pathway continues to provide treatment alternatives across a range of malignancy types. Several agents, including idelalisib, copanlisib and duvelisib, not only inhibit the PI3K pathway, but also have effects on associated mechanisms including the ATK and mTOR pathways. The advent of PI3K-specific small molecular inhibitors has led to increased efficacy with avoidance of an excessive toxicity profile. Key enzymes of the PI3K pathway exhibit differing expression in tissue types and roles in tumor pathogenesis. Copanlisib (BAY 80-6946) is a pan-specific PI3K small molecule inhibitor for four key isoforms with increased activity against PI3Kα and PI3Kδ, both important in B-cell malignancies. Follicular lymphoma is one of the most common indolent B-cell non-Hodgkin lymphomas worldwide. Follicular lymphoma like other indolent B-cell non-Hodgkin lymphomas is beleaguered by high relapse rates and the need for subsequent therapy options. Based on efficacy and a limited toxicity profile, copanlisib received accelerated US Food and Drug Administration approval for the treatment of adult patients with relapsed follicular lymphoma following two lines of therapy. Here, we review the development of copanlisib and the role of this agent in the treatment of follicular lymphoma.

Adjuvant IL-7 potentiates adoptive T cell therapy by amplifying and sustaining polyfunctional antitumor CD4+ T cells.

Increased availability of homeostatic cytokines is considered a major mechanism by which lymphodepletion enhances the efficacy of adoptive T cell therapy (ACT). IL-7 is one such cytokine capable of augmenting the function of tumor-reactive CD8+ T cells. However, whether host-derived IL-7 plays a role in driving the proper function of CD4+ T cells in an ACT setting remains unclear. Here we report that lymphodepleting chemotherapy by cyclophosphamide (CTX) does not lead to increased availability of the endogenous IL-7 in mice. Despite of a paucity of IL-7 in the immune milieu, CTX preconditioning allowed adoptively transferred naïve tumor-specific CD4+ T cells to undergo effector differentiation and regain IL-7Rα expression, giving rise to IL-7-responsive polyfunctional CD4+ effector cells. Correspondingly, supplementation of exogenous recombinant IL-7 markedly amplified and sustained polyfunctional CD4+ effector cells, resulting in improved therapeutic outcome in a mouse lymphoma model. We further demonstrated that the immune-enhancing effects of IL-7 were also applicable to donor CD4+ T cells pre-activated under Th1 polarizing condition. These findings suggest caution in relying on the endogenous IL-7 to enhance donor T cell expansion and persistence after lymphodepleting chemotherapy, and highlight the usefulness of recombinant IL-7 as an adjuvant for adoptive immunotherapy.

Persistent indolent pancolonic marginal zone lymphoma of MALT-type with plasmacytic differentiation - A rare post-transplant lymphoma?

Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is associated with chronic inflammatory disorders. We present an indolent pancolonic MALT lymphoma occurring in a 39-year-old female with history of autoimmune hepatitis requiring liver transplant in 1997 and ulcerative colitis diagnosed in 2004. Random biopsies from a grossly unremarkable surveillance colonoscopy in 2015 revealed a dense monomorphic plasmacytoid infiltrate causing expansion of lamina propria without significant crypt infiltration or destruction. These cells were positive for CD79a and CD138 and showed lambda restriction; however, CD20, CD43, CD56, HHV8, and EBER were negative. A similar pancolonic infiltrate was identified in all prior colorectal biopsies from 2010 and 2012 upon retrospective review. Subsequent computed tomography of the abdomen revealed no bowel wall thickening nor enlarged lymph nodes. Bone marrow revealed involvement consistent with stage IV disease. Biopsies from 2010 and 2015 demonstrated clonal immunoglobulin gene rearrangement. MYD88 mutation was not detected. The overall features were indicative of MALT lymphoma. Although low-grade B-cell lymphomas are not considered part of the post-transplant lymphoproliferative disorder spectrum, such cases have been reported, and are typically EBV-negative. Patient underwent treatment with pentostatin for her MALT lymphoma reaching a sustained remission despite additional immunosuppression for resurgent hepatic dysfunction. To our knowledge, this is the first reported case of EBV-negative pancolonic MALT lymphoma with plasmacytic differentiation post liver transplant presenting in an indolent, asymptomatic fashion with persistence for greater than five years successfully managed without compromising the patient's liver transplant.

The impact of antibiotic usage on the efficacy of chemoimmunotherapy is contingent on the source of tumor-reactive T cells.

In recent years the combined use of chemotherapy and immunotherapy, collectively termed chemoimmunotherapy, has emerged as a promising treatment option for patients with cancer. Antibiotics are commonly used to reduce infection-related complications in patients undergoing chemotherapy. Intriguingly, accumulating evidence has implicated gut microbiota as a critical determinant of host antitumor immune responses, raising the question as to whether the use of broad-spectrum antibiotics would invariably diminish tumor response to chemoimmunotherapies. We investigated the impact of antibiotics on the therapeutic outcomes of cyclophosphamide (CTX) chemotherapy and adoptive T-cell therapy (ACT) where CTX was used as the host-conditioning regimen in mice. We show that antibiotic prophylaxis dampened the endogenous T cell responses elicited by CTX, and reduced the efficacy of CTX against B-cell lymphoma. In the ACT setting, antibiotics administration impaired the therapeutic effects of adoptively transferred tumor-specific CD4+ T cells in mice with implanted colorectal tumors. In contrast, long-term antibiotic exposure did not affect the efficacy of ACT using CD19-targeting chimeric antigen receptor (CAR) T cells in mice with systemic B-cell lymphoma, although it correlated with prolonged CAR expression and sustained B-cell aplasia. Our study demonstrates that chemoimmunotherapies may have variable reliance on intestinal microbiota for T cell activation and function, and thus have different sensitivities to antibiotic prophylaxis. These findings may have implications for the judicial use of antibiotics in cancer patients receiving chemoimmunotherapies.

Releasing the Brake on the Immune System: The PD-1 Strategy for Hematologic Malignancies.

Manipulation of the immune system as a viable cancer treatment strategy has re-emerged. The programmed death 1 (PD-1) pathway is an important, physiologic immune checkpoint necessary to limit autoimmune processes but co-opted by tumors to suppress the antitumor response and allow tumor escape. Blockade of the PD-1 pathway through the use of PD-1 or PD ligand 1(PD-L1) antibodies releases this brake on the immune response. The anti-PD-1 antibodies have produced encouraging results across a broad range of malignancies. Many hematologic malignancies have usurped the PD-1 pathway. Recent investigations have explored the use of anti-PD-1 therapy in hematologic malignancies, with encouraging results. Incorporation of PD-1 blockade into the treatment algorithms for hematologic malignancies is currently being pursued in multiple active clinical trials. Here we review the data on anti-PD-1 monoclonal antibodies to date and discuss ongoing and future clinical trials.

Factors predicting survival in peripheral T-cell lymphoma in the USA: a population-based analysis of 8802 patients in the modern era.

Current prognostic models for peripheral T-cell lymphoma (PTCL) have multiple limitations, and questions exist regarding applicability to current patients. We utilized the Surveillance Epidemiology and End Results (SEER)-18 database to evaluate factors affecting overall survival (OS) of PTCL in the modern era and identified 8802 patients between 2000-2010. Most subtypes of PTCL increased in incidence during the study period. In univariate analyses, age >55 years, black race, advanced stage, absence of extra-nodal disease, omission of radiation therapy (RT) and high-risk histology each predicted inferior OS (P < 0·0001). Multivariate analysis (MVA) demonstrated that hepatosplenic, enteropathy-associated and extra-nodal Natural Killer/T cell histologies, each had hazard ratios >1·5 (P ≤ 0·0001) for death. Further, age ≥55 years, black race and advanced stage maintained their significance in the MVA (P < 0·0001 each). Based on the significant factors, a prognostic model was constructed and subsequently validated in an independent cohort. The new model incorporated age, stage, histology and race, with an OS ranging from 9 months (highest risk group) to 120 months (lowest risk group). In summary, this is the largest study of PTCL patients in the modern era that provides risk stratification utilizing a new prognostic model that can be incorporated into future prospective clinical trials.

Blocking tumor escape in hematologic malignancies: the anti-PD-1 strategy.

Immunotherapy remains an important tool for treatment of hematologic malignancies. The Programmed Death-1 (PD-1) immune checkpoint pathway has emerged as a mechanism of tumor evasion from the anti-tumor immune response. The recent development of anti-PD-1 monoclonal antibodies has offered a targeted approach to cancer therapy. Several agents are in various stages of development and have shown clinical responses across a broad spectrum of both solid and hematologic malignancies. The use of anti-PD-1 therapy in hematologic malignancies is limited but has demonstrated clinical responses in relapsed/refractory disease following multiple lines of therapy. PD-1 blockade may reduce relapse rates for patients who fail to obtain a complete remission prior to autologous hematopoietic cell transplant. The role of the PD-1 pathway for tumor escape is reviewed. We explore the use of anti-PD-1 therapy in hematologic malignancies. The proposed mechanism of PD-1 blockade as a modulator of the innate and acquired immune response is considered. Finally, the challenges of anti-PD-1 therapy and the future direction of investigation in this area are reviewed.

Pidilizumab in the treatment of diffuse large B-cell lymphoma.

INTRODUCTION: The programmed death-1 (PD-1) immune checkpoint pathway is an emerging target in the treatment of hematologic malignancies. Pidilizumab is an mAb that binds to PD-1 and is a safe and well-tolerated therapy. Recent data have shown clinical activity utilizing this strategy in diffuse large B-cell lymphoma (DLBCL). AREAS COVERED: The role of PD-1 expression in hematologic malignancies is explored. Recent clinical trials including the results of a Phase I trial in hematologic malignancies and a Phase II trial of pidilizumab following autologous hematopoietic stem-cell transplant (AHSCT) are reviewed. EXPERT OPINION: We review data that suggest that PD-1 is a promising target in the treatment and management of DLBCL. Changes in immune subsets following administration of pidilizumab are felt to represent on-target responses. The improvement in progression-free survival (PFS) following AHSCT supports a response to therapy. Importantly, the improvement in PFS for patients with positive FDG-PET/CT following AHSCT indicating residual disease further supports direct activity of pidilizumab in DLBCL.

Higher soluble P-selectin is associated with chronic venous insufficiency: the San Diego Population Study.

INTRODUCTION: P-selectin is a cell adhesion molecule shown to play a role in venous thromboembolism. We evaluated whether higher P-selectin is associated with chronic venous insufficiency (CVI). MATERIALS AND METHODS: In a cohort of 2408 participants, the San Diego Population Study, peripheral venous disease was established by symptoms, clinical examination, and ultrasound. We measured P-selectin in a subsample of 352 CVI cases frequency matched to controls. Cases included four hierarchical groups of increasing severity of CVI. RESULTS: The association of P-selectin with CVI considering all cases was weak, with an age, race and sex-adjusted odds ratio (OR) of 1.3 (95% CI 1.0-2.2) for values in the 3rd versus 1st tertile. The OR for cases in the two most severe groups was 2.3 (95% CI 1.2-4.2). Addition of body mass index to the model reduced this OR to 1.9 (95% CI 1.0-3.6). CONCLUSIONS: Higher circulating P-selectin was associated with more severe CVI, but not CVI overall. Results support that platelet and endothelial cell activation may be involved in the pathogenesis of CVI.