Ansell, Stephen M.

Abstract Purpose: TNF-related apoptosis inducing ligand (TRAIL) expression by immune cells contributes to antitumor immunity. A naturally occurring splice variant of TRAIL, called TRAILshort, antagonizes TRAIL-dependent cell killing. It is unknown whether tumor cells express TRAILshort and if it impacts antitumor immunity. Experimental Design: We used an unbiased informatics approach to identify TRAILshort expression in primary human cancers, and validated those results with IHC and ISH. TRAILshort-specific mAbs were used to determine the effect of TRAILshort on tumor cell sensitivity to TRAIL, and to immune effector cell dependent killing of autologous primary tumors. Results: As many as 40% of primary human tumors express TRAILshort by both RNA sequencing and IHC analysis. By ISH, TRAILshort expression is present in tumor cells and not bystander cells. TRAILshort inhibition enhances cancer cell lines sensitivity to TRAIL-dependent killing both in vitro and in immunodeficient xenograft mouse models. Immune effector cells isolated from patients with B-cell malignancies killed more autologous tumor cells in the presence compared with the absence of TRAILshort antibody (P < 0.05). Conclusions: These results identify TRAILshort in primary human malignancies, and suggest that TRAILshort blockade can augment the effector function of autologous immune effector cells. See related commentary by de Miguel and Pardo, p. 5546

Abstract Purpose: T-cell immunoglobulin and ITIM domain (TIGIT), a member of the immune checkpoint family, is important in normal T-cell biology. However, the phenotypical profile and clinical relevance of TIGIT in follicular lymphoma is largely unknown. Experimental Design: Biopsy specimens from a cohort of 82 patients with follicular lymphoma were analyzed using mass cytometry to explore the phenotype and biological and clinical significance of TIGIT+ T cells. Results: TIGIT is highly expressed on intratumoral T cells and its expression alters T-cell phenotype in follicular lymphoma. TIGIT is abundantly expressed on Treg cells, resulting in an enhanced suppressive property. TIGIT expression on non-Treg/TFH T cells defines a population that exhibits an exhausted phenotype. Clinically, increased numbers of TIGIT+ T cells are associated with inferior patient outcomes and poor survival. We observe that anti–PD-1 therapy with pembrolizumab alters the phenotype of TIGIT+ T subsets and identifies a role for CD28 expression on TIGIT+ T cells in treatment response. Conclusions: The current study provides a comprehensive analysis of the phenotypic profile of intratumoral TIGIT+ T subsets and their prognostic relevance in follicular lymphoma. Inhibition of TIGIT signaling may be an additional mechanism to prevent T-cell suppression and exhaustion in B-cell lymphoma.

Abstract Purpose: We sought to improve upon frontline bendamustine/rituximab (BR) induction therapy followed by rituximab maintenance in untreated high-risk follicular lymphoma (FL). Patients and Methods: Patients were randomized to BR induction followed by 2-year rituximab maintenance (BR-R), BR with bortezomib and rituximab maintenance (BVR-R), or BR followed by lenalidomide (1 year) with rituximab maintenance (BR-LR). Dual primary objectives were complete remission (CR) rate and 1-year disease-free survival (DFS); 289 patients enrolled (NCT01216683). Results: For induction, 92%, 87%, and 86% of patients randomized to BR-R, BVR-R, or BR-LR received six cycles, respectively. CR rate with BR versus BVR induction was 62% versus 75%, respectively (P = 0.04). One-year DFS rates with BR-R versus BR-LR were 85% versus 67%, respectively (P = 0.0009). This was due to an imbalance in CR rates post-BR induction and discontinuation due to adverse events (AEs). The most common grade 3–4 AEs for BVR versus BR were neutropenia and sensory neuropathy (12% vs <1%); 83% of the latter occurred with intravenous bortezomib. The most common grade 3–4 AEs related to LR versus rituximab maintenance were neutropenia 66% versus 21%, respectively (P < 0.0001), and febrile neutropenia 10% versus 2%, respectively (P = 0.05). The overall treatment-related mortality was 1.4%. With 5-year median follow-up, 3-year PFS rates for BR-R, BVR-R, and BR-LR were 77%, 82%, and 76%, respectively (P = 0.36) with OS rates of 87%, 90%, and 84%, respectively (P = 0.79). For prognostication, CR rate and POD-24 were associated with survival. Conclusions: Altogether, neither bortezomib added to BR induction nor lenalidomide added to rituximab maintenance immediately post-BR induction is recommended in untreated FL.

Abstract Approximately 90% of limited-stage Hodgkin lymphoma (HL) patients are projected to be cured with standard therapy, but many do not live their expected life span because of late treatment–related complications. New treatment paradigms are needed to reduce the use of radiation therapy (RT) as well as conventional chemotherapy drugs while improving upon current standard-of-care survival outcomes. In this phase 2 multicenter study, patients with non-bulky limited-stage HL received doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by brentuximab vedotin (BV) consolidation. Forty-one patients were enrolled, and patient characteristics included median age of 29 years (range, 19 to 67 years), 58% were female, 45% had unfavorable disease, and 98% had stage II disease. Based on positron emission tomography (PET)–based risk stratification, patients received 2 to 6 cycles of ABVD followed by 6 cycles of BV. After ABVD followed by BV, 95% of evaluable patients (37 out of 39; 95% confidence interval [CI], 83%-99%) achieved PET-negative status. In the intent-to-treat patient population, the estimated 3-year progression-free survival (PFS) rate was 92%, and the overall survival (OS) rate was 97%, with a median follow-up of 47 months. All 37 patients who achieved negative PET status after BV consolidation effectively avoided RT and remain in remission with estimated 3-year PFS and OS rates of 100%. In conclusion, BV demonstrates encouraging clinical activity when it follows ABVD therapy in limited-stage HL. Early incorporation of BV may reduce the use of RT as well as conventional chemotherapy drugs while achieving favorable survival outcomes in risk-stratified patients with non-bulky limited-stage HL. This trial was registered at www.clinicaltrials.gov as #NCT01578967.

e20035 Background: HDMTX is a vital treatment of lymphoma secondary to central nervous system penetrance. MTX is nephrotoxic and may cause acute kidney injury (AKI). AKI results in delayed MTX elimination, increased hospital length of stay (LOS) and intensive care unit (ICU) stays. Our aim was to characterise the complications and associated 48-hour MTX levels in lymphoma patients undergoing HDMTX. Methods: A retrospective review of the electronic medical record was conducted to identify lymphoma patients who received HDMTX from 1/1/2002 to 12/31/18. We assessed the incidence of AKI using AKIN criteria, ICU admission, and LOS across 48 hour MTX levels per the table. Results: 2704 cycles of HDMTX were identified. The mean age was 64 years, 54% were male and 72.2% received high dose (≥8g/m2). A significant increase in AKI severity (p < 0.0001) and LOS (p < 0.01) occurred with increasing 48 hour MTX levels, (p < 0.001, Table). All 7 patients requiring dialysis had MTX levels > 10. ROC curve analysis for AKI grade ≥ 2 demonstrated a 48 hour MTX level threshold of 1.28 (AUC 0.79) with relative risk of 7.6 (95% CI 5.3-11) and odds ratio of 8.8 (95% CI 5.9-13.1). A significant increase occurred in LOS across escalating 48 hour MTX level subgroups (p < 0.01, Table). A significant rise in ICU admissions occurred with increasing MTX levels ( < 0.01% for MTX < 2 compared to 15% with MTX > 5). Conclusions: Complications of HDMTX are significantly increased with elevated 48 hour MTX levels, particularly with levels > 1 μmol/L. [Table: see text]

e20033 Background: HDMTX is an important component of lymphoma therapy due to its central nervous system penetration. Although HDMTX can be safely administered to most patients, it can cause significant toxicity with those who have prolonged exposure to high plasma concentrations of MTX due to delayed elimination. Therefore, serum MTX concentration monitoring is still a standard approach for identifying patients at high risk of developing MTX toxicity. A majority of MTX is excreted within the first 48 hours of infusion. Higher MTX plasma concentrations at 48 hrs increase the likelihood of delayed MTX elimination. This study will assess baseline characteristics associated with high 48-hour MTX levels (≥ 1µM) which has been associated with increased risk of complications. Methods: A retrospective review of the electronic medical record was conducted to identify lymphoma patients who received HDMTX from 1/1/2002 to 12/31/18. Baseline demographics including age, gender, comorbidities, body surface area, BMI, weight and baseline chronic kidney disease (CKD) were recorded. Demographics, HDMTX dosing per protocol (3.5g/m2 vs 8g/m2), HDMTX adjusted by renal function (CrCl < 100), and ratio of MTX dose to BSA (MTX/BSA) were compared to 48 hour MTX levels. Analysis was performed in JMP 15. Results: 2553 cycles were of HDMTX were identified. There was a significant association of increasing age, (p = 0.039), male patients (p < 0.001), 8g/m2 dosing (p < 0.001), higher MTX dose (p < 0.001), MTX/BSA (p < 0.001), GFR by CKD-EPI (p < 0.001) and lower number of comorbidities (p < 0.001) with 48-hour MTX levels ≥1. There was no significant association of 48-hour MTX levels ≥1 and GFR by Cockcroft-Gault (p = 0.73), baseline CKD (p = 0.78), and renal adjusted HDMTX (p = 0.52). Multivariate analysis revealed significance for MTX/BSA, gender, BSA, GFR by CKDEPI (p < 0.001), and age (P = 0.0002). Conclusions: Hematologists should be aware that age, gender, GFR by CKD-EPI, and ratio of MTX dose to BSA are associated with elevated 48-hour MTX levels ≥1.

8550 Background: Waldenström Macroglobulinemia (WM) is a rare lymphoplasmacytic malignancy characterized by the presence of a recurrent point mutation in the MYD88 gene (MYD88L265P) in 80-95% of cases. Patients with MYD88WT genotype comprise a small subset that responds poorly to ibrutinib and other Bruton tyrosine kinase inhibitors. We examined the characteristics and outcome of WM patients with MYD88WT genotype predominantly treated with non-BTK inhibitor based therapies. Methods: Patients with a diagnosis of WM seen at Mayo Clinic, Rochester, between 1996 and 2018 were included. Their characteristics and outcomes were assessed from the time of active disease. Marrow MYD88 genotyping was assessed with an allele specific PCR assay (analytic sensitivity 1%). Categorical and continuous variables were compared using Chi square and Wilcoxon tests, respectively. Time-to-event analyses were performed using Kaplan Meier test. Results: Of 986 patients with active WM, MYD88 genotype data were available in 331 (34 %) patients; 72 (22%) and 260 (78%) patients harbored MYD88WT and MYD88L265P genotypes, respectively. The median follow-up was 5.8 years (95% CI: 5.0-6.5 years) from active WM; 6 years MYD88WT vs 5.4 years for MYD88L265P cohort. Median age was 63 years and 66 years in the MYD88WT and MYD88L265P cohorts, respectively (p = 0.07) with 46% and 53% patients being ≥65 years of age, respectively (p = 0.36). Pre-treatment marrow lymphoplasmacytic (LPL) infiltrate (median 40% for MYD88WT vs 60% for MYD88L265P; p = 0.001) and beta-2 microglobulin (median 3 µg/mL for MYD88WT vs 3.9 µg/mL for MYD88L265P; p = 0.02) were lower in the MYD88WT compared to the MYD88L265P cohort; other laboratory parameters at active disease were comparable. Per IPSSWM prognostic criteria, MYD88WT had fewer patients in the high risk group (18% for MYD88WT vs 42% MYD88L265P; p = 0.03). Patients with MYD88WT had higher likelihood of histological transformation [18% for MYD88WT vs 4% for MYD88L265P; odds ratio 5.8 (95% CI: 2.5-13.5; p < 0.0001)]. Among patients with treatment data available, only 35 (11%) patients received ibrutinib. The 5-year overall survival (OS) from active disease was comparable (85% in MYD88WT vs 82% in MYD88L265P cohort; p = 0.7). Conclusions: MYD88WT genotype in WM is associated with lower marrow LPL infiltration, lower likelihood of high-risk IPSSWM categorization and a higher likelihood of histological transformation in comparison to MYD88L265P mutant subpopulation. MYD88 genotype does not affect the OS from active disease in predominantly non-BTK inhibitor treated patients.

8052 Background: A significant proportion of patients with FL experience an early relapse and a subsequent poor outcome. While several prognostic indices have been developed, none were designed to predict early failure. Recently, we established that lack of intrafollicular CD4+ T-cell expression predicted risk of early failure, and integrating this microenvironment biomarker with the Follicular Lymphoma International Prognostic Index, termed BioFLIPI, further improved identification of FL patients at risk of early failure ( Blood 2019;134(suppl1):121). However, the microenvironment may be influenced by the genetic composition of tumor. We investigated whether the CD4 biomarker and BioFLIPI were impacted by genetic features of the tumor as assessed by a 23-gene expression prognostic score ( Lancet Oncol 2018;19:549-61). Methods: Of the 186 cases with FL grade 1-3A treated with immunochemotherapy (IC) in our prior study, 152 had digital expression quantification of 23 selected genes (23-GEP score), which used RNA from formalin-fixed, paraffin-embedded samples. Event-free survival (EFS) was defined as time from diagnosis to progression, relapse, retreatment, or death. Early failure was defined as failing to achieve EFS at 24 months. Risk of early failure was estimated using odds ratios (ORs) and 95% confidence intervals from logistic regression models. We also used Cox regression to assess associations with continuous EFS and overall survival (OS). Results: 28% of patients failed to achieve EFS24. Lack of CD4+ intrafollicular expression (38% of patients, OR = 2.33, p = 0.024) and high risk 23-GEP score (26% of patients, OR = 3.52, p = 0.001) each predicted early failure, and in a multivariable model that included FLIPI, both CD4+ (OR = 2.26, p = 0.046) and 23-GEP score (OR = 2.26, p = 0.0.057) remained predictors. Similarly, BioFLIPI modeled as a continuous score (1-4, OR per one point increase = 2.31, p < 0.001) predicted early failure, and the association remained (OR = 2.14, p < 0.001) when the high risk 23-GEP score (OR = 2.79, p = 0.013) was included in the model. When stratified on 23-GEP score, BioFLIPI was a stronger predictor of early failure in low risk (74%, OR = 2.51, p = 0.002) relative to high risk (26%, OR = 1.55, p = 0.27) patients. Similar patterns were observed for EFS and OS. Conclusions: CD4+ T-cell infiltrate and tumor gene expression appear to be independently predictive of early failure in newly diagnosed FL patients treated with IC. Future studies should integrate and validate these measures.

8030 Background: There is growing interest in the identification of modifiable patient-specific factors that may predict response to immune checkpoint inhibitors (ICIs) in classical Hodgkin lymphoma (cHL). Recently, it has been proposed that antibiotic use could decrease the efficacy of ICIs in the treatment of advanced solid malignancies. The objective of our study is to assess whether antibiotic use prior to or concurrent with ICIs is associated with changes in outcomes in patients with cHL. Methods: Patients who received a PD-1 or CTLA-4 blocker for the treatment of cHL at Mayo Clinic Rochester between January 1, 2011 and October 20, 2018 were identified. We conducted a longitudinal retrospective chart review to identify those who received antibiotics within 30 or 90 days prior to initiation or concurrent with ICI therapy. Univariate cox regression analysis was used to assess for an association between antibiotic use and overall survival (OS) and progression-free survival (PFS) within these groups; a time-dependent variable was used for concurrent antibiotic use. Results: A total of sixty-two patients were identified (61% male, median age at ICI initiation 35 years [range: 19-87]). Median duration of follow up from ICI start was 38 months (range: 4-78). Twenty-one patients (34%) received antibiotics within 90 days of initiation of ICI, of which thirteen (21%) received antibiotics within 30 days. Thirty-five patients (57%) received antibiotics concurrently with ICI. Concurrent and prior antibiotic use within 90 days of ICI were both associated with inferior PFS (concurrent HR = 6.38 [95% CI 3.02-13.47]; 90-day HR = 2.21 [95% CI 1.10-4.47]) and OS (concurrent HR = 8.77 [95% CI 1.91-40.36]; 90-day HR = 2.96 [95% CI 1.09-8.04]). Conclusions: Antibiotic use is associated with inferior outcomes in patients with cHL treated with ICIs in this single institution cohort. This may reflect potential antibiotic effects on the gut microbiome (GMB) and immune system as has been suggested in prior studies. Further confirmatory studies and examination of potential confounding covariates are needed.