Subsequent Malignant Neoplasms of the Gastrointestinal Tract after Blood or Marrow Transplantation - a BMTSS Report

Background and Purpose: Subsequent malignant neoplasms (SMNs) are a leading cause of non-relapse mortality after blood or marrow transplantation (BMT). Cancers of the gastrointestinal (GI) tract are of special interest since their clinical behavior is often aggressive, but early detection through screening is possible for specific GI malignancies. There is limited information regarding the risk of GI SMNs following BMT. The purpose of this study was to report the risk of GI SMNs after BMT and to identify specific exposures associated with increased risk. Materials and Methods: The BMT Survivor Study (BMTSS) is a multi-institutional retrospective cohort study of patients transplanted between 1974 and 2014, with survival ≥2y. Disease and treatment characteristics were obtained from institutional databases and medical records. GI SMNs were identified by review of the BMTSS survey or death records and confirmed by pathology report and/or medical record review. Standardized incidence ratios (SIRs) were calculated to determine excess risk of GI SMNs compared with the general population. Fine-Gray competing risks models examined the association between treatment exposures and GI SMNs. Results: Clinical/demographic characteristics of the cohort are provided in Table 1. The 6,710 BMT recipients in this cohort contributed 62,479 person-years of follow-up, yielding 148 patients with GI SMNs occurring a median of 8.9y (range, 0.3-36.6y) from BMT. The GI SMNs in the cohort included colorectal (n=45), liver (n=36), pancreatic (n=27), esophageal (n=22), gastric (n=11), and other GI (n=7) cancers. By age 70, the cumulative incidence of a GI SMN was 4.8% for allogeneic BMT recipients vs. 1.9% for autologous BMT recipients (p<0.0001, Fig 1). The SIR for a GI SMN after BMT was 1.95 for allogeneic BMT recipients vs. 1.03 for autologous BMT recipients (p=0.8). The risk of esophageal (SIR=3.19, p<0.01), liver (SIR=3.06, p<0.01) and pancreatic cancer (SIR=1.79, p<0.01) was increased when compared to the general population whereas the risk for gastric (SIR=1.15, p=0.6) and colorectal cancers (SIR=0.86, p=0.3) was not. Radiation exposure: Exposure to TBI at age <30y was associated with significantly higher risk for colorectal (SIR=2.67, p=0.003), stomach (SIR=5.16, p=0.005), and liver (SIR=11.61, p<0.001) cancers; the risks were not elevated when TBI exposure occurred at age >60 (Fig 2). The cumulative incidence of GI SMNs by age 70 was significantly higher (p<0.0001) among patients who received high-dose TBI (≥8Gy: 4.8%) vs. those who received low-dose TBI (<8Gy: 2.5%) or no TBI (2.1%) (Fig 3). High-dose TBI (and not low-dose) was associated with a 2.5-fold higher risk of colorectal cancer (95%CI=1.3-4.7). Pre-BMT abdominal radiation was associated with 9.55-fold increased risk of GI SMN (95%CI=2.5-36.5) among allogeneic BMT recipients; the association was primarily driven by pancreatic and esophageal cancer. Chemotherapeutic agents: Pre-BMT anthracyclines (HR=4.84, 95%CI=1.2-20.4) and etoposide conditioning (HR=2.87, 95%CI=1.6-5.3) were associated with an increased risk of liver cancer. Cytarabine conditioning was associated with increased risk of colorectal cancer (HR=3.08, 95%CI=1.4-6.9). Chronic GvHD: Risk of esophageal cancer was 9.6-fold higher among allogeneic BMT recipients with chronic GvHD (95%CI=3.3-28.4), when compared with those who received an autologous BMT. Conclusions: This study provides evidence that allogeneic BMT survivors are at increased risk for developing GI SMNs in the setting of specific pre-BMT and BMT-related therapeutic exposures and chronic GvHD. In particular, exposure to myeloablative doses of TBI at age <30y and conditioning with cytarabine and etoposide were associated with increased risk. In addition, pre-BMT exposure to abdominal radiation and anthracyclines were associated with specific types of GI SMNs. These findings and the very high risk of esophageal cancer among those with chronic GvHD provide a framework for developing personalized screening recommendations for those at highest risk. Figure 1 Figure 1. Disclosures McDonald: Varian Medical Systems: Consultancy, Research Funding. Weisdorf: Fate Therapeutics: Research Funding; Incyte: Research Funding. Forman: Mustang Bio: Consultancy, Current holder of individual stocks in a privately-held company; Lixte Biotechnology: Consultancy, Current holder of individual stocks in a privately-held company; Allogene: Consultancy. Arora: Syndax: Research Funding; Pharmacyclics: Research Funding; Kadmom: Research Funding.

Late-occurring Venous Thromboembolism in Allogeneic Blood or Marrow Transplant Survivors - a BMTSS-HiGHS2 Risk Model

Background: Allogeneic blood or marrow transplant (BMT) recipients are at risk for venous-thromboembolism (VTE) because of high-intensity therapeutic exposures, comorbidities and a pro-inflammatory state due to chronic graft vs. host disease (GvHD). The long-term risk of VTE in allogeneic BMT survivors remains unstudied. Methods: Participants were drawn from the BMT Survivor Study (BMTSS), a retrospective cohort study that included patients who underwent transplantation between 1974 and 2014 and survived ≥2y after BMT. The BMTSS survey collected information on sociodemographics, health behaviors and chronic health conditions along with age at diagnosis. Details regarding primary cancer diagnosis, transplant preparative regimens, type of transplant and stem cell source were obtained from institutional databases and medical records. We analyzed the risk of VTE in 1,554 2y survivors of allogeneic BMT compared to 907 siblings. Using backward variable selection guided by minimizing Akaike's information criterion, we created a prediction model for risk of late-occurring VTE. Results: Allogeneic BMT survivors had a 7.3-fold higher risk of VTE compared to siblings (95%CI: 4.69-11.46, p<0.0001). After a median follow-up of 11y (inter-quartile range: 6-18y), and conditional on surviving the first 2y after BMT, the cumulative incidence of late-occurring VTE was 2.4% at 5y, 4.9% at 10y and 7.1% at 20y after BMT. Older age at BMT (hazard ratio [HR]=1.02/y, 95%CI=1.01-1.04, p=0.002), use of immunosuppressive medications (HR=2.28, 95%CI=1.41-3.38, p=0.0008), obesity (HR=1.06/unit increase in body mass index, 95%CI=1.02-1.10, p=0.002), history of stroke (HR=3.71, 95%CI=1.66-8.27, p=0.001), chronic GvHD (HR=1.62, 95%CI=1.00-2.60, p=0.049), and use of peripheral blood stem cells (PBSCs) as source of stem cells compared to bone marrow (HR=2.73, 95%CI=1.65-4.50, p<0.0001) were associated with increased VTE risk. The final model for VTE risk applied at 2y post-BMT ("HiGHS2") included History of stroke, chronic GvHD, Hypertension, Sex (male vs. female) and Stem cell source (PBSCs vs. other) (corrected C-statistics: 0.73; 95%CI=0.67-0.79), and was able to classify patients at high and low VTE risk (10y cumulative incidence 9.3% vs. 2.4%, p<0.0001). Conclusions: The BMTSS HiGHS2 risk model when applied at 2y post-BMT can be used to inform targeted prevention strategies for patients at high risk for late-occurring VTE.

Association between learning and memory problems and health outcomes after blood or marrow transplantation (BMT): A BMT survivor study (BMTSS) report.

12014 Background: Cognitive impairment after BMT for hematologic malignancies typically involves processing speed, attention and working memory. Survivors perceive these deficits as learning and/or memory problems. However, limited information exists regarding learning/memory problems experienced by survivors several years after BMT. We addressed this gap using the BMTSS. Methods: BMTSS is a retrospective cohort study examining long-term outcomes of individuals who survived ≥2y after BMT performed between 1974 and 2014 at three transplant centers. Study participants completed a 255-item questionnaire covering diagnosis by a healthcare provider of health conditions (including learning/memory problems), sociodemographic characteristics, and functional status. We used a nested matched case-control study design. Cases consisted of individuals with learning/memory problems developing after BMT (n = 543). Each case was matched to a BMTSS participant without memory problems (controls: n = 543) using the following criteria: cancer diagnosis, race/ethnicity, type of BMT (allogeneic or autologous), and time from BMT. Multivariable conditional logistic regression analysis was used to identify clinical factors (age at BMT, stem cell source, chronic graft vs. host disease [cGvHD], total body irradiation [TBI], fatigue, pain) and demographic factors (household income, education, sex) associated with learning/memory problems. We also examined the association between learning/memory problems and instrumental activities of daily living (IADL). Analyses were stratified by type of BMT. Results: For all survivors (n = 1,086), mean age at BMT was 40.7y and at study participation was 53.3y (18-85); 47% of the study population was females; 78% were non-Hispanic whites; 31% reported an annual household income < $50k. Primary diagnoses included leukemia (50%), lymphoma (36%), and other (14%); 55% received an allogeneic BMT (36% developed cGvHD); 54% received TBI; and 68% received peripheral blood stem cells. Allogeneic BMT survivors with fatigue (odds ratio [OR] = 2.2, 95% CI, 1.4-3.3; p = 0.001), significant pain (OR = 1.8, 95% CI, 1.1-2.9; p = 0.02) and < college education (OR = 1.6, 95% CI, 1.1-2.5; p = 0.02) had higher odds of reporting learning/memory problems. Autologous BMT survivors exposed to TBI (OR = 2.8, 95% CI, 1.4-5.4; p = 0.003) and reporting significant pain (OR = 1.7, 95% CI, 1.0-2.9; p = 0.05) had higher odds of reporting learning/memory problems. Learning/memory problems were associated with increased odds of impairments in IADL in both autologous (OR = 2.1, 95% CI, 1.1-4.0; p = 0.03) and allogeneic (OR = 2.0, 95% CI, 1.2-3.3; p = 0.01) BMT survivors. Conclusions: Modifiable risk factors, such as fatigue and pain, can be targeted to mitigate the learning/memory problems and improve the functional outcomes of BMT survivors.

Coronary Heart Disease Risk in Blood or Marrow Transplant Survivors

INTRODUCTION: Exposure to total body irradiation (TBI) increases the risk for cardiovascular risk factors (CVRFs) such as diabetes, hypertension and dyslipidemia in Blood or Marrow Transplant (BMT) survivors with the potential to increase the risk of post-BMT Coronary Heart Disease (CHD). Chest radiation is associated with accelerated atherosclerosis in conventionally treated patients. These factors, with or without additional factors such as smoking likely place BMT survivors at a high risk for CHD. Yet, a comprehensive evaluation of the risk of late-occurring CHD in BMT survivors is lacking. We addressed this gap using the resources offered by the BMT survivor study (BMTSS). METHODS: BMTSS includes patients transplanted between 1974 and 2014 at 3 US sites, and who had survived ≥2 years after BMT, and were alive and ≥18 years at BMTSS survey completion. The BMTSS survey asked participants to report chronic health conditions diagnosed by their healthcare provider (including CHD, diabetes, hypertension and dyslipidemia), along with age at diagnosis. The participants self-reported sociodemographics and health behaviors. Information regarding primary cancer diagnosis, therapeutic exposures, donor type, stem cell source, and history of chronic graft vs. host disease (GvHD; for allogeneic BMT recipients) was abstracted from medical records. A cohort of 1,131 siblings completed the BMTSS survey and served as a comparison group. We obtained informed consent from all participants. RESULTS: The study included 3,479 BMT survivors; 50.3% had received an allogeneic BMT, 54.8% were males, and 71.4% were non-Hispanic whites. Median age at study participation was 59 years (interquartile range [IQR]: 48-66 years) for BMT survivors and 57 years (IQR: 46-64 years) for siblings. BMT survivors were followed for a median of 9 years (range: 2-41 years) from BMT. CHD developed after BMT in 122 BMT survivors (52 allogeneic, 70 autologous). BMT recipients compared with siblings: After adjusting for sociodemographics and comorbidities, allogeneic BMT survivors were at a 7.2-fold higher odds (95%CI: 4.0-13.0, p&lt;0.0001) and autologous BMT recipients at a 11.7-fold higher odds (95%CI: 6.8-20.2, p&lt;0.0001) of reporting CHD as compared to siblings. Allogeneic BMT survivors: The 20 year cumulative incidence of CHD was 4.7% for allogeneic BMT recipients. Increasing age at BMT (HR=1.05/year, 95%CI: 1.02-1.07, p&lt;0.0001), male sex (HR=2.09, 95%CI: 1.14-3.82, p=0.017), history of CVRFs (HR=3.6, 95%CI: 1.72-7.41, p=0.0006), and pre-BMT targeted chemotherapy such as tyrosine kinase inhibitors (HR=2.7, 95%CI: 1.10-6.77, p=0.030) were associated with increased CHD risk. The 20 year cumulative incidence of CHD among patients with CVRFs was 6.6% vs. 1.9% (p=0.005) among those who did not have CVRFs (Fig 1). Autologous BMT survivors: The 20 year cumulative incidence of CHD was 9.1% for autologous BMT recipients. The risk factors for CHD in autologous BMT survivors included: increasing age at BMT (HR=1.06/year, 95%CI: 1.03-1.09, p&lt;0.0001), male sex (HR=2.3, 95%CI: 1.30-3.90, p=0.004), history of smoking (HR=1.66, 95%CI: 1.03-2.67, p=0.038), CVRFs (HR=1.77, 95%CI: 1.04-3.01, p=0.036), arrhythmia (HR=1.85, 95%CI: 1.01-3.42, p=0.048) and history of pre-BMT chest radiation (HR=4.56, 95%CI: 2.1-9.88, p=0.0001). For every 1 Gray increase in the dose of chest radiation, there was a 4% increase in the risk of CHD, p=0.0002. The 20 year cumulative incidence of CHD among patients with CVRFs was 10.2% vs. 7.4% among those who did not have CVRFs (p=0.04) (Fig 2). CONCLUSION: BMT survivors are at a 7-fold to 12-fold higher risk of CHD compared with a sibling comparison group. CVRFs are independent risk factors for CHD both among allogeneic and autologous BMT recipients. Pre-BMT chest radiation further increases this risk in autologous BMT recipients. These findings suggest a need for aggressive management of CVRFs in BMT recipients to prevent CHD-related morbidity. Disclosures Gangaraju: Sanofi Genzyme, Consultant for Cold Agglutinin Disease: Consultancy. Weisdorf:FATE Therapeutics: Consultancy; Incyte: Research Funding. Arora:Pharmacyclics: Research Funding; Kadmon: Research Funding; Syndax: Research Funding; Fate Therapeutics: Consultancy.

Severe/Life-Threatening/Fatal Chronic Health Conditions (CHCs) after Allogeneic Blood or Marrow Transplantation (BMT) in Childhood - a Report from the BMT Survivor Study (BMTSS)

Background: Allogeneic BMT is a curative option for children with malignant and non-malignant diseases. Nonetheless, the high intensity of therapeutic exposures at a young age increases the risk of organ compromise and thereby the risk of developing CHCs. Yet, there is limited information regarding CHC risk after allogeneic BMT performed in childhood. We address this gap in patients undergoing allogeneic BMT between 1974 and 2014 at 3 participating transplant centers. Methods: BMT recipients and a sibling comparison group (or the parents of participants &lt;18y) completed a 255-item questionnaire that included sociodemographics and health conditions. A severity score (grades 3 [severe] or 4 [life-threatening]) was assigned to CHCs using CTCAE, v. 5.0. Deceased BMT recipients received a CHC-specific grade 5. Risk of severe/life-threatening CHC in BMT survivors vs. siblings: We calculated the cumulative incidence of CHCs for survivors and siblings as a function of attained age. We used logistic regression for estimating the risk of grade 3-4 conditions in survivors compared to siblings, adjusting for sex, age at study, race/ethnicity, education, household income, and health insurance. Risk of severe/life-threatening/fatal CHC in BMT recipients: We used proportional subdistribution hazards model (Fine-Gray) for competing risks to identify predictors of grade 3-5 CHCs, adjusting for demographics, primary disease, conditioning agents, disease status at BMT and chronic GvHD status. Results: 848 patients had received allogeneic BMT at age ≤22 and survived ≥2y after BMT (563 alive at study; 285 deceased after surviving ≥2y). Primary diagnoses included ALL (29%), AML/MDS (28%), SAA (13%), other (30%); median age at BMT: 11.5y (range: 0.4-22.0); median length of follow-up 10.7y (2.0-41.4). Risk of severe/life-threatening CHC in 563 BMT survivors vs. 515 siblings: Cumulative incidence of grade 3-4 condition by age 30y among BMT recipients was significantly higher than that among siblings (38.5±2.7% vs. 5.4±1.0%, p&lt;0.0001), Figure 1. The adjusted odds of developing grade 3-4 CHCs were 8.9-fold higher in BMT survivors (95%CI 6.4-12.5). Higher odds were observed for developing cataracts (OR=48.2; 95%CI 17.9-129.5), heart disease (OR=11.4, 95%CI, 3.9-33.3), diabetes (OR=11.1; 95%CI 3.5-34.8), thyroid nodules (OR=6.6, 95%CI, 2.6-17.0), joint replacement (OR=4.4, 85%CI, 1.7-10.9), and sensorineural disorders (hearing loss/balance disorder/legally blind); OR=3.2, 95%CI, 1.5-6.8). Risk of severe/life-threatening/fatal CHCs in 848 BMT recipients: cumulative incidence of grades 3-5 CHCs was 60.5±3.0% at 40y (Figure 2). The most prevalent grade 3-5 CHCs were second malignancy (11.8%), cataract (5.9%), cardiovascular disease (5.8%), sensorineural disorder (4.4%), diabetes (3.4%), and joint replacement (2.9%). The risk of grades 3-5 CHCs was higher among females (HR=1.3, 95%CI 1.0-1.6), age &gt;12y at BMT (HR=1.4, 95%CI 1.1-1.8) and among those exposed to TBI (HR=1.7, 95%CI 1.2-2.3). Conclusions: Two-year survivors of allogeneic BMT performed in childhood had an almost 10-fold higher risk of severe/life-threatening CHCs compared to siblings. By age of 30, 39% of the survivors had developed a severe or life-threatening CHC. The results of the present study call for close follow-up, from the time of transplantation continuing throughout life. Disclosures Weisdorf: Incyte: Research Funding; FATE Therapeutics: Consultancy. Arora:Fate Therapeutics: Consultancy; Syndax: Research Funding; Kadmon: Research Funding; Pharmacyclics: Research Funding.

147 CD155 blockade boosts alloreactive natural killer cell antitumor effects against osteosarcoma

BackgroundPediatric patients with relapsed and refractory osteosarcoma have poor prognoses with few treatment options. Allogeneic bone marrow transplant (BMT) has not yet shown a graft-versus-tumor (GVT) effect for osteosarcoma. Natural killer (NK) cells demonstrate antitumor activity against osteosarcoma, but adoptively transferred NK cells have limited proliferation, cytotoxicity, and persistence in vivo. To enhance an NK-specific GVT effect, we propose blocking the poliovirus receptor CD155 checkpoint molecule, which is overexpressed on osteosarcoma and can engage both activating and inhibitory receptors on NK cells. The impact of CD155 blockade on GVT and graft-versus-host-disease (GVHD) is unknown.MethodsNK cells from C57BL/6 (B6) mice were expanded with recombinant IL-15/IL-15R and analyzed by flow cytometry. Cytotoxicity assays were performed with IL-15 expanded B6 NK cells and mKate2-expressing K7M2 murine osteosarcoma at a 1:1 ratio with blockade of CD155 and CD155 ligands. To test efficacy of NK cell infusion and CD155 blockade after allogeneic BMT, BALB/c mice were lethally irradiated, transplanted with allogeneic B6 bone marrow, and challenged with luciferase-expressing K7M2 on day 0. At day 7, mice received IL-15 expanded B6 NK cells intravenously with either anti-IgG control or anti-CD155 antibody intraperitoneally and IL-2 subcutaneously on days 7 and 11. Mice were monitored for tumor growth by bioluminescence, and toxicity by GVHD using weight loss and clinical scores.ResultsCompared to unexpanded murine NK cells, IL-15 expanded NK cells (n = 6) show increased expression of NKG2D (65.33 ± 10.77% NKG2D+, p = 0.0077; 1030 ± 177.0 MFI, p = 0.0101) and an increased ratio of the CD155 activating (CD226) to inhibitory (TIGIT) ligand expression (11.71 ± 4.121, p = 0.0362). In cytotoxicity assays with IL-15 expanded allogeneic murine NK cells (n = 3 replicates), CD155 blockade enhances K7M2 osteosarcoma lysis (60.62 ± 3.19%, p = 0.0189) compared to IgG control (29.01 ± 7.66%). CD226 blockade decreased tumor killing (10.62 ± 8.51%, p = 0.0053) compared to CD155 blockade. In vivo allogeneic murine NK cell infusion and anti-CD155 antibody treatment after allogeneic BMT decreased tumor area under the curve by 44.3% compared to IgG control, without exacerbating GVHD.ConclusionsThese findings demonstrate that blockade of CD155 enhances an allogeneic NK cell-specific GVT effect for osteosarcoma treatment without exacerbating GVHD. CD155 blockade has the potential to improve usage of allogeneic BMT and NK cell adoptive immunotherapy as a combination treatment for osteosarcoma, and perhaps other pediatric sarcomas.AcknowledgementsThis work was supported by grants from the National Institute of General Medical Sciences/NIH T32 GM008692 and Training in Cancer Biology Training Grant NIH T32 CA009135 (to MMC), St. Baldrick’s Stand up to Cancer (SU2C) Pediatric Dream Team Translational Research Grant SU2C-AACR-DT-27-17, NCI/NIH R01 CA215461, American Cancer Society Research Scholar Grant RSG- 18-104-01-LIB, and the Midwest Athletes Against Childhood Cancer (MACC) Fund (to CMC). SU2C is a division of the Entertainment Industry Foundation. Research grants are administered by the American Association for Cancer Research, the scientific partner of SU2C. The contents of this article do not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the US government.

Total Body Irradiation and Risk of Breast Cancer After Blood or Marrow Transplantation: A Blood or Marrow Transplantation Survivor Study Report

PURPOSE To examine the association between total body irradiation (TBI) and subsequent breast cancer in women treated with blood or marrow transplantation (BMT) for hematologic malignancies. PATIENTS AND METHODS Participants were drawn from the BMT Survivor Study (BMTSS), a retrospective cohort study that included patients who underwent transplantation between 1974 and 2014 and survived for ≥ 2 years after BMT. Patients with pre-BMT chest radiation or a history of breast cancer were excluded. Participants completed the BMTSS survey, which included details regarding breast cancer diagnosis. Subsequent breast cancer was confirmed by pathology report review or physician notes. Cox proportional hazards models assessed the association between TBI and subsequent breast cancer. Standardized incidence ratios were calculated to determine the excess risk of subsequent breast cancer compared with that in the general population. RESULTS A total of 1,464 female BMT survivors (allogeneic: n = 788; autologous: n = 676) participated, with a median follow-up of 9.3 years from BMT. TBI was used in 660 patients (46%). Thirty-seven women developed subsequent breast cancer (allogeneic: n = 19; autologous: n = 18). Multivariable analysis revealed that exposure to TBI was associated with an increased risk of subsequent breast cancer among allogeneic BMT survivors (hazard ratio [HR], 3.7 [95% CI, 1.2 to 11.8]; P = .03) and autologous BMT survivors (HR, 2.6 [95% CI, 1.0 to 6.8]; P = .048). Pre-BMT exposure to alkylating agents was associated with an increased risk of subsequent breast cancer among autologous BMT survivors (HR, 3.3 [95% CI, 1.0 to 9.0]; P = .05). Compared with that in the general population, exposure to TBI at age < 30 years was associated with a 4.4-fold higher risk of subsequent breast cancer in allogeneic BMT survivors and a 4.6-fold higher risk in autologous BMT survivors. CONCLUSION The association between TBI and subsequent breast cancer, especially among those exposed at a young age, as well as pre-BMT exposure to alkylating agents, should inform breast cancer screening for early detection.

Genome Wide Association Study (GWAS) of cognitive impairment after blood or marrow transplantation (BMT) for hematologic malignancy.

1536 Background: Cognitive impairment is prevalent in hematologic malignancy patients treated with BMT (autologous: 18.7%; allogeneic: 35.7%; Sharafeldin JCO; 2018). Given the inter-individual variability in risk of cognitive impairment in this population, we investigated the role of genetic susceptibility using a genome-wide single nucleotide polymorphism (SNP) array platform to identify novel genetic associations. Methods: Discovery: Cognitive function was assessed objectively in 239 adult BMT recipients at pre-specified timepoints: pre-BMT and at 6 mo, 1y, 2y, and 3y post-BMT. A global deficit score (GDS - a summary score of 14 standardized neuropsychological tests) was computed for each patient; a higher score indicated greater cognitive impairment. SNPs passing standard quality control filters ( > 1.4M) were used for analysis. Linear mixed effects models used GDS as the outcome, adjusted for age, sex, BMT type, baseline cognitive reserve, and the first four principal components. We used additive, codominant, and genotype models and an adjusted genome-wide significance threshold of 1.25 x 10−8. Replication: An independent cohort of 544 BMT survivors (192 cases with self-endorsed cognitive problems and 352 controls without) was used for replication. Results: Discovery: Median age at BMT was 51.3y; primary diagnoses: 47% leukemia, 32% lymphoma, 21% multiple myeloma; 57% males; 69% non-Hispanic whites: 50% allogeneic BMT, median GDS score = 0.22 (range 0-2). Forty-four SNPs were significantly associated with increased GDS (additive model: 3 SNPs; codominant model: 20 SNPs; genotype model: 21 SNPs). Estimates ranged from increase in GDS score by 0.28 points for each additional copy of risk allele, p = 1.07 x 10−8 to increase in GDS score by 1.82 points for two copies of risk allele, p = 2.3 x 10−11. Replication: Median age at BMT was 44y; primary diagnoses: 32% leukemia, 49% lymphoma, 19% multiple myeloma; 54% males; 80% non-Hispanic whites: 34% allogeneic BMT. Three SNPs were successfully replicated: rs116334183 resides within lncRNA-SEMA6D-2, which facilitates neuronal migration; rs13286152 86kb downstream of TLE-1, which promotes neuronal survival; and rs12486041 0.36Mb downstream from lncRNA-SPTSSB-1, which regulates sphingolipid production in neuronal axons and 0.36Mb upstream from TOMM22P6 linked to neural repair. Conclusions: In this first GWAS of cognitive impairment post-BMT, we identify 3 SNPs with plausible links to genes implicated in neuronal integrity. Functional studies are currently underway.

Stroke Risk in Blood or Marrow Transplant (BMT) Survivors - a Report from the BMT Survivor Study (BMTSS)

BACKGROUND: BMT recipients are vulnerable to accelerated atherosclerosis due to prior exposure to radiation with or without chemotherapy, and consequent long-term cardiovascular morbidity, such as stroke. A comprehensive evaluation of the risk of late-occurring stroke in adult BMT survivors and the associated risk factors has not been performed. We addressed this gap using the resources offered by the BMTSS. METHODS: BMTSS includes patients transplanted between 1974 and 2014 at 3 US sites who survived ≥2y after BMT, were alive and ≥18y at BMTSS survey completion. The survey asked participants to report if a healthcare provider had diagnosed specific chronic health conditions (including stroke), or relapse of primary cancer or development of new cancer, along with age at diagnosis. The participants provided information on sociodemographics, health behaviors and medication use. Medical record abstraction was used for information regarding primary cancer diagnosis, therapeutic exposures (pre-BMT chemotherapy/radiation, transplant preparative regimens), stem cell source (autologous, allogeneic), graft type (bone marrow, cord blood or peripheral blood stem cells), and history of chronic graft vs. host disease (GvHD). A cohort of 908 siblings also completed the BMTSS survey and served as a comparison group. Informed consent was obtained from all participants. RESULTS: The study included 3,479 BMT survivors; 50.3% had received an allogeneic BMT, 54.8% were males; 71.4% were non-Hispanic whites. Median age at study participation was 59y (range: 18-89y) for BMT survivors and 57y (range: 18-90y) for siblings. Patient characteristics are shown in Table 1. BMT survivors were followed for a median of 9y (range: 2-41 y) from BMT. Stroke was reported by 136 BMT survivors (67 allogeneic, 69 autologous); of these, 75 (55%) patients developed stroke ≥2y after BMT. Conditional on surviving ≥2y after BMT, the 10y cumulative incidence of stroke was 3.8% (Fig 1), and was comparable for allogeneic (3.4±0.5%) and autologous (4.2±0.6%) BMT recipients, p=0.3. Stroke in BMT recipients compared with siblings: Using logistic regression, and after adjusting for sociodemographics, physical activity and relevant comorbidities, we found that allogeneic BMT survivors were at a 2.1-fold higher odds of reporting stroke as compared to siblings (95%CI: 1.2-3.7, p=0.01), and autologous BMT recipients were at a 1.7-fold higher odds of reporting stroke compared to siblings (95%CI: 0.9-3.0, p=0.09). Stroke after Allogeneic BMT: History of hypertension (HR=2.2, 95%CI: 1.2-3.9, p=0.007), venous thromboembolism (HR=3.4, 95%CI: 1.6-7.1, p=0.002), diagnosis of acute lymphoblastic leukemia (HR=4.9, 95%CI: 1.6-15.0, p=0.006), acute myeloid leukemia/ myelodysplastic syndrome (HR=5.2, 95%CI: 1.4-19.0, p=0.013) (ref: non Hodgkin lymphoma), pre-BMT exposure to alkylating agents (HR=3.3, 95%CI: 1.3-8.5, p=0.01) and pre-BMT neck radiation (HR=5.4, 95%CI: 1.2-23.8, p=0.03) were associated with increased stroke risk. Exercise was associated with lower stroke risk (HR: 0.5, 95%CI: 0.3-0.9, p=0.01). Stroke after Autologous BMT: The risk factors for stroke in autologous BMT survivors included: increasing age at BMT (HR=1.02/y, 95%CI: 1.0-1.1, p=0.05), history of hypertension (HR=1.8, 95%CI: 1.1-3.2, p=0.03), coronary heart disease (HR=2.8, 95%CI: 1.3-6.4, p=0.01) and venous thromboembolism (HR=2.3, 95%CI: 1.1-4.7, p=0.02). Relapse of primary disease or development of new cancer were not associated with increased stroke risk in either autologous or allogeneic BMT recipients. CONCLUSION: In this large study, we found that the incidence of stroke was 4% among BMT survivors, and that they are at an increased risk of developing stroke when compared to an unaffected comparison group. The study also identified subgroups among BMT survivors at increased risk of stroke such as those who received neck radiation and those with cardiovascular comorbidity. These findings suggest a need for increased awareness of stroke as a late complication of BMT, such that aggressive management of cardiovascular risk factors can be instituted among those at highest risk. Disclosures Weisdorf: Incyte: Research Funding; Fate Therapeutics: Consultancy; Pharmacyclics: Consultancy.

Microrna-31 Regulates T-Cell Metabolism Via HIF1α and Promotes Effector Function

MicroRNAs (miRs) repress gene expression at the post-transcriptional level via binding target mRNAs subsequently promoting mRNA degradation or impeding translation. Certain miRs influence the survival, differentiation, and function of T cells in cancer, infections, and autoimmunity. Uncontrolled T-cell allogeneic responses contribute to chronic graft-versus-host disease (cGVHD), a major cause of non-relapse mortality following allogeneic hematopoietic stem-cell transplantation (allo-HCT). Dysregulation of miR-31 is implicated in cancer, but how miR-31 impacts allogeneic T-cell response is unclear. Using oligonucleotide array, we found miR-31 was dramatically up-regulated in T cells under alloantigen-driven vs. homeostatic proliferation in recipient mice following bone marrow transplantation (BMT) (Figure 1A-B). To understand how miR-31 regulates T-cell responses to alloantigens, we utilized murine models of allogeneic BMT and donor mice with miR-31 conditional knock-out on their T cells. In a sclerodermatous cGVHD model (B6→BDF1), we observed that the recipients transferred with donor T cells deficient for miR-31 exhibited significantly alleviated disease (Figure 1C), reflected by attenuated fibrosis and pathologic damage in skin. In a bronchiolitis obliterans cGVHD model (B6→B10.BR), we found that the recipients of miR-31-deficient T cells had reduced airway resistance, elastance (Figure 1D) and pathological damage in the lungs as compared with those of WT T cells. The role of miR-31 in promoting T-cell pathogenicity was further confirmed when miR-31 was inhibited by administration of specific antagomir (locked nuclear acid anti-miR-31). We used mass cytometry to analyze donor immune cell reconstitution in recipient spleens after BMT. Consistent with attenuated disease manifestation, the recipients of miR-31-deficient T cells displayed improved reconstitution of donor T- and B- lymphocytes. The follicular T helper cells (TFH) instruct germinal center (GC) B-cell expansion, affinity maturation, and plasma cell differentiation, whereas follicular regulatory T cells (TFR) inhibit TFH -mediated B-cell activation and antibody production. We found that miR-31 deficient T cells differentiated into more TFR, but fewer TFH during alloresponses. As a result, the differentiation and activation of GC B cells and the generation of plasma cells were attenuated in the recipients of miR-31-deficient T cells. Furthermore, miR-31-deficient T cells exhibited defects in proliferation and survival in allogeneic recipients, resulting in fewer donor T cells in recipient thymus, skin and lungs. In the absence of miR-31, T cells differentiated less into Th17 cells but more towards Tregs (Figure 1E) in vivo. Those miR-31-deficient Tregs expressed higher levels of Neuropilin 1 and PD-L1, the markers associated with superior stability and suppressive function of Tregs. While miR-31 played little role on Th1 cell differentiation, it facilitated alloantigen-reactive iTregs losing Foxp3 and producing IFNγ after being transferred into allogeneic recipients. Hypoxia, a hallmark of inflamed and damaged tissue, can drive fibrosis and disease development through immune cell dysregulation. Upon activation, T cells rapidly increase their metabolic rate and switch from oxidative phosphorylation to aerobic glycolysis. We found that miR-31-deficient T cells exhibited reduced hypoxia-inducible factor 1α (HIF1α) signaling (glycolysis promotor), surface GLUT1 expression, and glucose uptake, but increased lipid droplet accumulation in allogeneic recipients, suggesting that miR-31 promotes metabolic switch from fatty acid β-oxidation to aerobic glycolysis in allo-reactive T cells (Figure 1F). Furthermore, under hypoxia (3% oxygen) but not normoxia (21% oxygen) conditions, miR-31 increased Th17 but decreased iTreg differentiation from naïve CD4 T cells in the presence of IL-6 and TGFβ in vitro. Taken together, miR-31 regulates T-cell expansion, differentiation, and metabolism via promoting HIF1α expression and hypoxia adaptation in allo-reactive T cells, which enhances T-cell effector function and pathogenicity after allogeneic BMT. Disclosures No relevant conflicts of interest to declare.