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Managing double-expressor lymphomas (DEL) is controversial given the dearth of data and lack of standardized guidelines on this high-risk subset of lymphomas. No prospective and few retrospective studies limited by either their sample size or short follow-up address the question of initial treatment of choice for DEL. We performed the largest analysis to date exploring R-CHOP vs DA-EPOCH-R in DEL.Adults with DEL diagnosed from 6/2012-2/2021 at 4 unique sites were retrospectively analyzed. Progression-free survival (PFS) was the primary endpoint. Key secondary endpoints include overall survival (OS), overall and complete response rates (ORR and CRR), cumulative incidence of relapse, and autologous hematopoietic cell transplantation (autoHCT) utilization.155 patients were included, 61 treated with R-CHOP and 94 with DA-EPOCH-R. 3-year PFS and OS were similar between R-CHOP and DA-EPOCH-R, 33.2% vs 57.2%,(P = .063), and 72.2% vs 71.6% (P = .43) after median follow-up times of 2.43 and 2.89 years, respectively. Patients65 had improved PFS with DA-EPOCH-R, hazard ratio 0.41 (P = .01). CRR and ORR rates were also similar. Relapse rates were not statistically different, 51.9% vs 28.6% (P = .069). AutoHCT utilization was higher with R-CHOP vs DA-EPOCH-R, 23.0% vs 8.5% (P = .017).Our findings do not support the use of DA-EPOCH-R over R-CHOP for DEL. Patients65 years may experience longer PFS with DA-EPOCH-R, but limitations to the analysis make this interpretation difficult.

In the last decade, a better understanding of the molecular pathogenesis of B-cell non-Hodgkin lymphomas has resulted in the development of novel targeted therapies, such as small molecule inhibitors of select kinases in the B-cell receptor pathway, antibody–drug conjugates, and small molecules that target a variety of proteins (eg, CD-19, EZH2, and XPO-1–mediated nuclear export). Anti-CD19 CAR T-cell therapy, first approved for relapsed/refractory (R/R) diffuse large B-cell lymphoma, has also emerged as a novel treatment option for R/R follicular lymphoma and mantle cell lymphoma. These NCCN Guideline Insights highlight the new targeted therapy options included in the NCCN Guidelines for B-Cell Lymphomas for the treatment of R/R disease.

Relapse after allogeneic stem cell transplant in unfavorable-risk acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) portends a poor prognosis. We conducted a single-center phase I dose-escalation study with lenalidomide maintenance in high-risk MDS and AML patients after allogeneic transplantation. Sixteen patients enrolled in a “3 + 3” study design starting at lenalidomide 5 mg daily, increasing in increments of 5 mg up to 15 mg. Lenalidomide was given for 21 days of a 28-day cycle for a total of six cycles. Most common dose-limiting toxicities were lymphopenia, diarrhea, nausea, and neutropenia. Two patients had acute graft-versus-host disease (GVHD), and five patients developed chronic GVHD. The maximum tolerated dose was 10 mg, after dose-limiting toxicities were seen in the 15 mg group. Two dose-limiting toxicities were seen from development of acute GVHD and grade III diarrhea. Limitations of the study include time to initiation at 6 months post transplant, as many high-risk patients will have relapsed within this time frame before starting maintenance lenalidomide. Overall, lenalidomide was well tolerated with minimal GVHD and low rates of relapse rates, warranting further study.

Background FLAG ± Ida (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin), is a salvage chemotherapy regimen for relapsed or refractory (R/R) acute myeloid leukemia (AML), with complete remission (CR) rates historically ranging from 52% to 63%. We review the outcomes for patients with R/R AML treated with FLAG ± Ida at the University of California Davis Comprehensive Cancer Center. Patients and Methods Adult patients (≥ 18 years) with R/R AML who received FLAG or FLAG + Ida from January 1, 2012 to October 31, 2016 were identified via chart review. Outcomes evaluated were CR, CR with incomplete hematologic recovery (CRi), overall response rate, overall survival (OS), relapse-free survival, and adverse events. Results Forty-two patients were included. The median age was 52 years (range, 23-73 years), and 57% were male. Sixteen (38.1%) patients had relapsed disease, and 26 (61.9%) had refractory disease. Most (n = 35; 83.3%) patients had European LeukemiaNet intermediate-risk AML. Responses were CR in 20 (47.6%) and CRi in 6 (14.3%). The median OS was 10 months (range, 0.8-51 months), and the median relapse-free survival was 12 months (range, 1-51 months) for responders. The median OS for patients who achieved CR was not reached, and the estimated 48-month survival rate was 56%. The median OS after CRi or no response was 3.47 and 2.17 months, respectively. The median OS was not significantly different when censored for stem cell transplant following chemotherapy, nor with use/deferral of idarubicin. The most common adverse effects were pancytopenia and infection. Conclusion Patient outcomes after treatment with FLAG ± Ida for R/R AML remain similar to prior reports, confirming its role as a salvage regimen for these patients.

Effective and tolerable treatments are needed for older patients with classical Hodgkin lymphoma. We report results for older patients with classical Hodgkin lymphoma treated in the large phase III ECHELON-1 study of frontline brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine (A+AVD) versus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). Modified progression-free survival per independent review facility for older versus younger patients (aged ≥60 vs.

Introduction Everolimus and bendamustine both have single-agent activity against lymphoid hematologic malignancies. We examined this combination in a group of heavily pretreated patients with non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), and multiple myeloma (MM). Patients and Methods In this phase I trial, 18 patients (8 with NHL, 6 with MM, and 4 with HL) were treated with bendamustine 90 mg/m2 on days 1 and 2 and everolimus from 5 to 10 mg daily on a 28-day cycle, for up to 4 cycles. Results Adverse events were generally mild and mostly hematologic in nature. The most frequent grade 3/4 adverse events were lymphopenia (61%), thrombocytopenia (22%), leukopenia (22%), neutropenia (17%), and fatigue (17%). Overall response rate varied by malignancy: diffuse large B-cell lymphoma, 20% (1 of 5 patients); HL (2 of 4 patients), 50%; MM, 80% (4 of 5 patients); and indolent lymphomas, 100% (3 of 3 patients). The maximum tolerated dose of everolimus was determined to be 7.5 mg daily. Conclusion The combination of everolimus and bendamustine appeared to be well-tolerated and relatively efficacious.

T-cell large granular lymphocyte (LGL) leukemia is a rare indolent neoplasm primarily treated with immunosuppression. Few therapies and no consensus exist for the optimal treatment of T-cell LGL leukemia refractory to immunosuppressive therapy. Here, we report a case of relapsed/refractory T-cell LGL treated with belinostat. A 57-year-old male presented with lymphocytosis and anemia and was found to have T-cell LGL, requiring frequent packed red blood cell transfusions. He was initially treated with methotrexate with no response after 7 months. He was then switched to cyclosporine and cyclophosphamide and experienced transfusion independence for 42 months before disease relapse. He was then started on belinostat with noted subsequent transfusion independence for greater than 15 months to date and decreased disease involvement on bone marrow biopsy. To our knowledge, this is the first reported case of belinostat use in relapsed/refractory T-cell LGL leukemia which resulted in a durable clinical and biologic response.

In herpesvirus replicating cells, host cell gene transcription is frequently down-regulated because important transcriptional apparatuses are appropriated by viral transcription factors. Here, we show a small peptide derived from the Kaposi’s sarcoma-associated herpesvirus transactivator (K-Rta) sequence, which attenuates cellular MYC expression, reduces cell proliferation, and selectively kills cancer cell lines in both tissue culture and a xenograft tumor mouse model. Mechanistically, the peptide functions as a decoy to block the recruitment of coactivator complexes consisting of Nuclear receptor coactivator 2 (NCOA2), p300, and SWI/SNF proteins to the MYC promoter in primary effusion lymphoma cells. Thiol(SH)-linked alkylation for the metabolic sequencing of RNA (SLAM seq) with target-transcriptional analyses further confirm that the viral peptide directly attenuates MYC and MYC-target gene expression. This study thus provides a unique tool to control MYC activation, which may be used as a therapeutic payload to treat MYC-dependent diseases such as cancers and autoimmune diseases., Shimoda et al. present evidence that a small functional peptide derived from the KSHV transactivator could be used to target MYC in cancer. The authors find that the peptide attenuates MYC expression, reduces cell proliferation, and selectively kills cancer cells in tissue culture and a xenograft tumor mouse model, by blocking recruitment of coactivator complexes (Nuclear receptor coactivator 2, p300, and SWI/SNF proteins) to the MYC promoter.

In the last decade, a better understanding of the molecular pathogenesis of B-cell non-Hodgkin lymphomas has resulted in the development of novel targeted therapies, such as small molecule inhibitors of select kinases in the B-cell receptor pathway, antibody-drug conjugates, and small molecules that target a variety of proteins (eg, CD-19, EZH2, and XPO-1-mediated nuclear export). Anti-CD19 CAR T-cell therapy, first approved for relapsed/refractory (R/R) diffuse large B-cell lymphoma, has also emerged as a novel treatment option for R/R follicular lymphoma and mantle cell lymphoma. These NCCN Guideline Insights highlight the new targeted therapy options included in the NCCN Guidelines for B-Cell Lymphomas for the treatment of R/R disease.

In herpesvirus replicating cells, host cell gene transcription is frequently down-regulated because important transcriptional apparatuses are appropriated by viral transcription factors. Here, we identified a small peptide derived from the Kaposi's sarcoma-associated herpesvirus transactivator (K-Rta) sequence, which attenuates cellular c-MYC expression, reduces cell proliferation, and selectively kills cancer cell lines in both tissue culture and a xenograft tumor mouse model. Mechanistically, the peptide functions as a decoy to block the recruitment of coactivator complexes consisting of Nuclear receptor coactivator 2 (NCOA2), p300, and SWI/SNF proteins to the MYC promoter in primary effusion lymphoma cells. Thiol(SH)-linked alkylation for the metabolic sequencing of RNA (​SLAM seq) with target-transcriptional analyses further confirmed that the viral peptide directly attenuates MYC and MYC-target gene expression. This study thus provides a unique tool to control MYC activation, which may have significant potential as a therapeutic payload to treat MYC-dependent diseases such as cancers and autoimmune diseases.

Allogeneic hematopoietic cell transplantation (alloHCT) can produce durable remissions in refractory lymphomas by relying on both myeloablative conditioning (MAC) and the subsequent graft-versus-ly...

Purpose: Rituximab and lenalidomide are effective for previously untreated and relapsed/refractory (R/R) indolent non-Hodgkin lymphoma (iNHL). However, long-term survival and predictive biomarkers are not well described. Patients and Methods: We conducted two phase II open-label trials involving 60 patients with previously untreated and R/R advanced-stage iNHL. Patients received lenalidomide and rituximab induction followed by continuous lenalidomide until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR). Correlative studies included plasma cytokine monitoring, flow cytometry of peripheral blood mononuclear cells (PBMC; days 0, 15, 30, and 60), and RNA sequencing (RNA-seq) of pretreatment tumor biopsies. Results: At a median follow-up of 63 months for previously untreated and 100 months for R/R, ORR was 82% for both. The 11 R/R patients who achieved complete remission remained in continuous remission for 16 to 141 months, thereafter. Median overall survival (OS) was not reached in the previously untreated and was 140 months (95% confidence interval, 53.4–140) in the R/R group. A mixed-effects linear regression model identified significant associations between Granzyme B+ (GranB+) CD8+ T cells and long-term complete response (LTCR; P = 5.3e-4). Furthermore, prior to start of therapy, treatment response could be predicted by B-cell and GranB+ CD8+ T-cell levels (% total lymphocytes). Conclusions: Rituximab plus lenalidomide followed by continuous lenalidomide is effective with manageable toxicity in patients with previously untreated and R/R iNHL. This regimen produces durable remissions, even in heavily pretreated patients, with some lasting greater than 10 years. GranB+ CD8+ T cells, B cells, and plasma IFNγ allowed prediction of LTCR but need validation in larger trials.

Aims The histone deacetylase inhibitor belinostat has activity in various cancers. Because belinostat is metabolized by the liver, reduced hepatic clearance could lead to excessive drug accumulation and increased toxicity. Safety data in patients with liver dysfunction are needed for this drug to reach its full potential in the clinic. Methods We performed a phase 1 trial to determine the safety, maximum tolerated dose (MTD) and pharmacokinetics of belinostat in patients with advanced cancer and varying degrees of liver dysfunction. Results Seventy-two patients were enrolled and divided into cohorts based on liver function. In patients with mild dysfunction, the MTD was the same as the recommended phase 2 dose (1000 mg/m2 /day). Belinostat was well tolerated in patients with moderate and severe liver dysfunction, although the trial was closed before the MTD in these cohorts could be determined. The mean clearance of belinostat was 661 mL/min/m2 in patients with normal liver function, compared to 542, 505 and 444 mL/min/m2 in patients with mild, moderate and severe hepatic dysfunction. Although this trial was not designed to assess clinical activity, of the 47 patients evaluable for response, 13 patients (28%) experienced stable disease. Conclusion While a statistically significant difference in clearance indicates increased belinostat exposure with worsening liver function, no relationship was observed between belinostat exposure and toxicity. An assessment of belinostat metabolites revealed significant differences in metabolic pathway capability in patients with differing levels of liver dysfunction. Further studies are needed to establish formal dosing guidelines in this patient population.

Background Clarithromycin (CL) is a macrolide antibiotic with anti-MM activity when combined with dexamethasone (dex), and imids. Immunomodulatory activity and altered dex metabolism are proposed mechanisms of CL activity, though concerns over toxicity remain. We designed a phase I/II study of pomalidomide (pom), ixazomib (ix), CL and dex (PICd) to assess the tolerability and efficacy of CL in RRMM. Methods The primary endpoints were the maximal tolerated and recommended phase 2 dose of PICd. Secondary endpoints were overall response rate (ORR)(≥ PR), disease control rate (DCR)(≥ SD), duration of response (DOR) and progression free (PFS) and overall survival (OS). Cycles were 28 days. CL 250 mg PO BID was given c1 d15-21 and d1-21 subsequently. Pom 4 mg PO daily for 21 days, ix 4 mg d1, 8, 15 and dex 40 mg (20 mg if age >75 years) d1, 8, 15 and 22 were given for 6 cycles. After C6, maintenance until unacceptable toxicity or PD consisted of reduced pom, ix, dex and CL doses at 2, 2.3, 20 and 250 mg respectively. CL was held during weeks 1-2 of cycle 1 to facilitate correlative studies. Results A total of 32 patients consented to study. Of these, 4 were unevaluable for response/survival due to rapid disease progression (n=2), late screen failure (n=1), and withdrawn consent (n=1). Of these, 3 were included in toxicity data. Median follow up was 20 months (mo). Median age was 68.5 (range 54 – 82), 74% were male. Median number of prior therapies was 2 (1 – 5). All patients had prior lenalidomide and proteasome inhibitor exposure. Of the 26 patients with FISH data, 15 (57%) had high risk cytogenetics. Of these, 9 (35%) had del(17p), 10 (38%) had + 1q and 2 (8%) had t(4;14). Four had del(17p) and +1q; 1 each had t(4;14) and del(17p) or +1q. At least 1 grade 3-4 adverse event (AE) was experienced by 17 (55%) patients. Grade 3-4 hematologic AEs were seen in 8 (26%), of which 5 (16%) had neutropenia. Ten (31%) experienced grade 3-4 non-hematologic AEs, of which infections were the most common [4 (13%) patients]. Grade 3-4 neuropathy was not seen. ORR was 75%, DCR was 100%; 13 patients (56%) achieved ≥VGPR while 4 (14%) achieved CR/sCR. High risk cytogenetics were not associated with ORR (Fisher exact test P=1) or ≥VGPR rates (Fisher exact test P=0.42). Median DOR was 23.2 mo (95% Confidence interval: 12.2 – not reached); median PFS was 24.7 mo (13.4 – NR). There was no difference in median PFS in patients with or without del(17p): 24.7 mo (7.5 – NR) vs 22.2 mo (11.0 – NR) respectively (log rank P=0.4). Patients with + 1q had a median PFS of 13.4 mo (11 – NR) vs to 39.6 mo (25 – NR) in those without +1q (log rank P=0.09). Median OS was 37.3 mo (21.5 – NR). Correlative studies examining immune effector subsets before and after the addition of CL will be presented at the meeting. Conclusions Overall, PICd is a promising all PO regimen which combines convenient administration, tolerable side effect profile, and long duration of disease control.

Autologous stem cell transplant (aHSCT) is associated with improved survival for multiple myeloma (MM) patients but may be associated with second primary malignancy (SPM) development. Using the California Cancer Registry linked to statewide hospitalization data, we determined the cumulative incidence (CMI) of SPMs more than 1 year after MM diagnosis, accounting for the competing risk of death. AHSCT recipients were matched 1:2 to non-aHSCT patients. Adjusted hazard ratios (aHR) were estimated using the Fine and Gray method. Among 16,331 patients, 933 (5.7%) developed a SPM more than 1 year after diagnosis. The 10-year CMI of developing any SPM was 6.6%, 5.7% for solid tumor SPM and 0.9% for hematologic malignancies. The 10-year CMI of developing any SPM was similar among aHSCT [9.1% (7.7–10.7%)] and non-aHSCT [7.5% (6.5–8.6%)] (P = 0.26) recipients and there was no difference in solid-tumor SPMs (P = 0.98). The 10-year CMI of hematologic SPMs was higher among aHSCT recipients [2.1% (1.4–2.9%) vs. 0.8% (0.5–1.2%); P = 0.005], corresponding to a 1.3% absolute increase and an aHR of 1.51 (1.01–2.27). Ten-year myeloma-specific and non-cancer mortality rates were 59% (58.2–60.0%) and 18.1% (17.4–18.8%), respectively. Although aHSCT was associated with a small increase in hematologic SPMs, mortality was driven by MM and non-cancer causes.

Relapsed/refractory acute myeloid leukemia (AML) is a devastating disease with a poor prognosis and represents a major unmet medical need. We report on a real-world academic center experience of treating 25 patients with relapsed/refractory AML using venetoclax in combination with decitabine or azacitidine, which is not otherwise widely evaluated in the current literature. Our patients come from a large, socioeconomically and geographically diverse area including the majority of Northern California. Most had ELN Adverse Risk (52%) or Intermediate Risk (44%) AML, and most had an ECOG Performance Status of 1 (64%). Over half (52%) had prior hypomethylating agent exposure, and 40% had Secondary AML. We observed an overall response rate of 52%, with eight patients (32%) achieving composite complete remission. Median overall survival was 5.5 months, and for patients achieving composite complete remission this was 21.6 months. One-year estimated overall survival was 38%. Three patients were able to proceed directly to stem cell transplant for consolidation, and all three were alive at last follow-up, ranging 13.8–24.0 months. We found venetoclax in combination with hypomethylating agents to be well tolerated and potentially efficacious in securing long-term remissions for patients with relapsed/refractory AML.

Multiple myeloma (MM) is an incurable malignancy, marked by end-organ damage that is frequently irreversible. Progressive disease (PD) can be defined as morbid PD, associated with new-onset hypercalcemia, renal insufficiency, anemia, or lytic bone lesions (CRAB symptoms), or as asymptomatic biochemical progression. The frequency of morbid versus asymptomatic PD and its effect on survival is unknown. Our aim was to determine the incidence of morbid PD, and to evaluate if this influences survival.Data from 2 phase III trials of transplant-ineligible patients with newly diagnosed MM were included in a post hoc analysis.Of 2082 patients enrolled, 1243 (59.7%) experienced PD. At first progression, 543 (43.7%) patients had morbid PD; 12 (2.2%) had hypercalcemia, 271 (49.9%) had renal insufficiency, 370 (68.1%) developed anemia, and 79 (14.5%) developed new or enlarged bone lesions. A total of 700 (56.3%) patients had asymptomatic PD. Patients with morbid PD had worse second progression-free survival (PFS) versus patients with asymptomatic biochemical PD (median second PFS, 11.5 months vs. 20.0 months; hazard ratio, 1.63; 95% confidence interval, 1.43-1.85; P .0001) and worse overall survival (OS) (median OS, 23.2 months vs 39.3 months; hazard ratio, 1.51; 95% confidence interval, 1.30, 1.74; P .0001).Morbid PD occurs frequently and is associated with inferior second PFS and OS. As CRAB symptoms may not reverse with therapy, morbid PD is a meaningful event, and its association with a shortened PFS adds validity to PFS as a relevant endpoint in patients with MM.

Introduction We designed a multicenter, phase Ib dose-escalation trial of carfilzomib with bendamustine and rituximab in patients with relapsed/refractory non-Hodgkin lymphoma ( NCT02187133 ) in order to improve the response rates of this difficult-to-treat population. Chemoimmunotherapy with bendamustine and rituximab has shown activity in a variety of lymphomas, and proteasome inhibitors have demonstrated pre-clinical synergy and early clinical activity in this population. The objectives were to determine the maximum tolerated dose of carfilzomib and the preliminary efficacy of this combination. Patients and Methods The protocol followed a 3+3 design of carfilzomib dose escalation combined with standard doses of bendamustine and rituximab. Patients were treated for up to 6 cycles with an interim positron emission tomography/computed tomography after cycle 3. Results Ten patients were treated on the dose-escalation phase. The study was terminated at a carfilzomib dose of 56 mg/m2, and the maximum tolerated dose was not reached. The most common grade 3/4 adverse event was thrombocytopenia. There was 1 dose-limiting toxicity observed, grade 3 febrile neutropenia, and there were no treatment-related deaths. The overall response rate was 40% (complete response rate, 30%), with a median duration of response of 12 months and a median progression-free survival of 2.1 months. Conclusion Carfilzomib in combination with bendamustine and rituximab is a safe and well-tolerated treatment for patients with relapsed/refractory non-Hodgkin lymphoma. Preliminary data indicate that this combination may have efficacy with an acceptable side effect profile in this heavily pre-treated patient population with limited treatment options.

Background: While many humanized monoclonal antibodies utilize complement-dependent cytotoxicity, the complement depleting effects of these antibodies and the impact of complement replacement on treatment response are not well-described. Methods: We conducted a phase 2 trial involving patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Patients were treated with ofatumumab with fresh frozen plasma (FFP) used as a source of complement replacement. The primary endpoint was objective response rate. Correlative endpoints included complement levels (C3 and C4) and complement activity (CH50) which was drawn at baseline and after ofatumumab with FFP administration. Results: Among 12 enrolled patients, overall response rate was 83% with two patients (17%) achieving a complete response. While only two (17%) patients had low complement activity at baseline, eight (67%) developed low levels of complement activity after ofatumumab treatment with FFP replacement. The magnitude of complement depletion did not correlate with response. Adverse events were minimal. The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Conclusions: The combination of ofatumumab and FFP demonstrated tolerability and surprising activity in high-risk CLL patients. Complement replacement should be studied further as a minimally toxic approach to improve efficacy of monoclonal antibody-based regimens. J Hematol. 2020;9(3):79-83 doi: https://doi.org/10.14740/jh721

Introduction : CD47, a cell-surface ligand overexpressed in various malignancies, binds to SIRPα on effector macrophages to promote tumor cell evasion of phagocytosis. Blockade of the CD47-SIRPα interaction provides a pro-phagocytic signal which enhances phagocytosis mediated by tumor-targeting antibodies such as rituximab. Agents targeting CD47 in combination with rituximab have demonstrated promising clinical activity in R/R NHL; however, the broad expression of CD47 leads to frequent on-target, off-tumor toxicities, including treatment-emergent hemolytic anemia. CC-95251 is a novel, fully human immunoglobulin G1 antibody that binds to SIRPα on monocytes and macrophages to potently block the CD47-SIRPα interaction. Here we report interim results from a phase 1 study evaluating CC-95251 combined with rituximab in patients (pts) with R/R NHL. Methods: CC-95251-ST-001 (NCT03783403) is a multicenter, open-label, phase 1, dose-escalation and expansion study of CC-95251 in pts with advanced solid tumors and CD20+ R/R NHL. The primary objectives of the dose-escalation stage presented here are to evaluate the safety and tolerability of escalating doses of CC-95251 combined with rituximab and to define the maximum tolerated dose (MTD) and/or recommended phase 2 dose for the combination in pts with R/R NHL. Pts with CD20+ NHL who had progressed on standard anticancer therapy or for whom no approved conventional therapy was available were eligible for inclusion. Dose-escalation was conducted using an adaptive, 2-parameter Bayesian logistic regression model with overdose control. Pts were treated in 28-day cycles with CC-95251 administered intravenously at 3, 10, or 20 mg/kg every week (QW) and rituximab 375 mg/m 2 given on days 1, 8, 15, and 22 of cycle 1, on day 1 of cycles 2-5, and on day 1 of every other cycle from cycle 6 to 24 until disease progression or unacceptable toxicity. Results: As of April 30, 2021, 18 pts were enrolled and 17 had received ≥ 1 dose of CC-95251 and rituximab. Median age of the enrolled study population was 69 (range 30-84) years. Treated pts had received a median of 4 (range 1-7) prior systemic therapies, including 14/17 (82%) pts with confirmed prior rituximab exposure. Enrolled tumor types included R/R diffuse large B-cell lymphoma in 14 (78%) pts, follicular lymphoma in 2 (11%), and mantle cell lymphoma and marginal zone lymphoma in 1 (6%) pt each. Of the pts with available response data for prior lines of therapy (LOT), 7 (41%) had disease confirmed to be refractory to any prior LOT, including 5 (29%) refractory to rituximab-containing regimens, and 5 (29%) to their last LOT. Pts received a median of 3 (range 1-12) cycles of CC-95251, with a median duration of treatment of 14.1 (range 1.1-47.3) weeks. There were no CC-95251 dose reductions. Five (29%) pts experienced ≥ 1 treatment-emergent adverse events (TEAEs) leading to CC-95251 dose interruption. To date, the MTD has not been reached for the combination of CC-95251 and rituximab. The most common (≥ 30%) TEAEs of any grade were neutropenia (11/17 [65%]), infections (9/17 [53%]), hypokalemia (6/17 [35%]), and hypomagnesemia (6/17 [35%]; Table). Grade ≥ 3 TEAEs reported in ≥ 2 pts were neutropenia (9/17 [53%]) and infections (4/17 [24%]). No treatment-related anemia, a notable toxicity of some anti-CD47 therapies, was reported with CC-95251 and there were no treatment-related deaths. The overall response rate was 41% (7/17), with 2/17 (12%) pts achieving a complete response (Figure). The median time to response was 7.6 weeks. Median duration of response has not been reached as responses are ongoing. Pharmacokinetic (PK) analysis showed that CC-95251 exhibited dose-proportional increases in exposure at doses > 3 mg/kg QW indicating saturation of nonlinear clearance pathways or target saturation. Full receptor occupancy on peripheral monocytes was achieved at doses > 3 mg/kg QW. The estimated terminal half-life when in the linear range of clearance was approximately 12 days. No substantial differences in PK were observed at the given dose levels for CC-95251 monotherapy versus CC-95251 combined with rituximab. Conclusions: CC-95251, a novel anti-SIRPα antibody, demonstrated a manageable safety profile and promising efficacy in combination with rituximab in pts with heavily pretreated CD20+ R/R NHL. The study continues to enroll in the dose-expansion phase. Updated safety and efficacy data will be presented. Figure 1 Figure 1. Disclosures Strati: Astrazeneca-Acerta: Research Funding; Roche-Genentech: Consultancy. Hawkes: Regeneron: Speakers Bureau; Specialised Therapeutics: Consultancy; Bristol Myers Squib/Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck KgA: Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel and accommodation expenses, Research Funding, Speakers Bureau; Janssen: Speakers Bureau; Antigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Merck Sharpe Dohme: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Ghosh: Karyopharma: Consultancy, Honoraria; Genmab: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Adaptive Biotech: Consultancy, Honoraria; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Genentech: Research Funding; AbbVie: Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau. Tuscano: BMS, Seattle Genetics, Takeda, Achrotech, Genentech, Pharmacyclics, Abbvie: Research Funding. Chu: Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria; BI: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria; Eli Lilly: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Merck KgaA: Other: DSMB. Patel: Bristol Myers Squibb: Current Employment. Burgess: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Hege: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Chhagan: Bristol Myers Squibb: Current Employment. Boyanapalli: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Day: Tracey Day: Current Employment. Shen: Bristol Myers Squibb: Current Employment. Mehta: Affirmed; Kite/Gilead; Roche-Genetech; Celgene/BMS; Oncotartis; Innate Pharmaceuticals; Seattle Genetics; Incyte; Takeda; Fortyseven Inc/Gilead; TG Therapeutics; Merck; Juno Pharmaceuticals/Bristol Myers Squibb: Research Funding; Seattle Genetics; Incyte; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics; Incyte; TG Therapeutics: Consultancy.

Background Ponatinib, a third-generation BCR-ABL1 tyrosine kinase inhibitor (TKI), + hyper-CVAD showed remarkable activity against Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), and may be superior to chemotherapy + earlier generation TKIs in terms of depth of remission, event-free survival (EFS), and overall survival (OS). However, this regimen's efficacy and tolerability have yet to be externally validated. Here, we summarize our real-world experience with ponatinib + hyper-CVAD for untreated Ph+ ALL and other Ph+ acute or blast phase leukemias. Methods We retrospectively analyzed all adults treated at the University of California, Davis (UCD) from March 2012 to May 2021 with ponatinib + hyper-CVAD upfront. The primary endpoints were 3-year OS and EFS. Secondary endpoints were complete molecular response (CMR), measurable residual disease (MRD) negativity by multiparameter flow cytometry (MFC), complete cytogenetic response (CCyR) rates, and adverse events (AEs). Time to event analyses were done via the Kaplan-Meier method. Patients alive were censored at their last follow-up date. Patients undergoing allogeneic hematopoietic cell transplant (HCT) after 6 months of achieving complete remission (CR) were censored at the time of HCT for the landmark analysis. Patients with missing data were excluded from the response analyses. Results We identified 13 Ph+ ALL patients who received ponatinib + hyper-CVAD for initial induction. The baseline characteristics for the Ph+ ALL patients are summarized in Table 1. The median follow-up was 16 months. The median number of hyper-CVAD cycles completed was 8 (range, 1-8) with ponatinib. Two patients proceeded to HCT in CR1, one at 3.5 months after starting induction, and due to difficulty controlling the patient's concurrent multiple myeloma prior to HCT and recovery from anti-neoplastic therapy, the second was delayed to 46 months after starting induction. The 3-year OS and EFS with ponatinib + hyper-CVAD were each 92% (95% confidence interval, 78.9-100) (Figure 1). Landmark analysis completed 6 months following CR showed a 3-year OS of 100% in patients treated with ponatinib + hyper-CVAD without HCT in first CR (CR1). The CMR, CCyR, and MRD-negativity by MFC rates with ponatinib were all 92.3% (12/13). The median time to CMR, CCyR, and MRD-negativity by MFC were 51 days, 22 days, and 53 days, respectively. Notable AEs with ponatinib include neutropenic fever (92%), bacterial infection (69%), transaminitis (38%), venous thromboembolism (31%), invasive fungal infection (15%), hemorrhage (15%), cerebrovascular accident (CVA) (15%), and tumor lysis syndrome (8%). One patient died during induction with ponatinib due to a bacterial infection. Two patients switched to a different TKI due to a CVA after 4 and 24 months. Only 2 patients did not complete 8 cycles of hyper-CVAD, due to death during induction (n=1) and proceeding to HCT after 3 cycles (n=1). As for similar Ph+ leukemias, 3 chronic myeloid leukemia with lymphoid blast crisis (CML-LBC), 1 CML with mixed phenotype blast crisis (CML-MPBC), and 1 with mixed phenotype acute leukemia (MPAL) were treated with ponatinib + hyper-CVAD. The MPAL patient achieved CMR within 55 days, while the CML-MPBC and 2 CML-LBC patients achieved CMR after HCT. The third CML-LBC patient is in CR with ongoing treatment. After median follow-up of 25 months, all 5 were alive, and only the MPAL patient relapsed 28 months after starting treatment and 1 year after HCT. Conclusion To our knowledge, this is the first report externally validating the efficacy and tolerability of ponatinib + hyper-CVAD for Ph+ ALL. We also show the feasibility of using this regimen in patients with Ph+ CML-LBC, CML-MPBC and MPAL. Despite the small sample size and retrospective nature, our study supports existing data demonstrating that this regimen challenges both the designation of Ph+ ALL as a high-risk disease and the trend to transplant in CR1. Our findings support that ponatinib + hyper-CVAD should be considered a standard of care for Ph+ ALL. Figure 1 Figure 1. Disclosures Kaesberg: Incyte: Speakers Bureau. Rosenberg: Takeda, Janssen: Speakers Bureau. Abedi: BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Speakers Bureau; Seattle Genetics: Speakers Bureau. Tuscano: Genentech, Pharamcyclics, Abbvie, BMS, Acrotech, Seattle Genetics, Takeda: Research Funding. Jonas: AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy; 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie: Other: Travel reimbursement. OffLabel Disclosure: Ponatinib is approved for Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ALL) that is resistant or intolerant to prior tyrosine kinase inhibitor therapy. In this study, we described outcomes with ponatinib in combination with hyperCVAD in the frontline setting, which is off-label.

Background: Cirmtuzumab (Cirm) is a humanized monoclonal antibody that inhibits the tumor promoting activity of ROR1 and has demonstrated additive/synergistic activity with many anticancer agents, including ibrutinib (Ibr). Methods: Patients (Pts) with relapsed or refractory (RR) MCL or treatment-naïve (TN) or RR CLL were enrolled. In Part 1 (Dose Escalation), doses of Cirm IV q2wks x5 then q4wks of 2-16 mg/kg and 300 or 600 mg were examined. Safety of Cirm alone was assessed during the first 28 days, then Ibr was started at approved doses for each indication. Cirm 600 mg IV q2wks x3 then q4wks in combination with Ibr starting day 0 was chosen as the recommended dosing regimen for use in Part 2 (Expansion) and Part 3 (CLL only, Cirm/Ibr vs. Ibr). MCL Part 1 is closed, and Part 2 is open for enrollment. CLL Parts 1, 2 & 3 are closed for enrollment. Results: As of 18Jun2021 data cutoff, 28, 34 and 28 pts were treated in MCL Parts 1 & 2, CLL Parts 1 & 2, and CLL Part 3 (Cirm/Ibr (n=18) or Ibr (n=10)). In Parts 1 & 2 MCL, the median number (#) of prior systemic regimens was 1.5 (1-4) including pts relapsing after Ibr (n=4), auto-SCT (n=6), auto-SCT/allo-SCT (n=1), or auto-SCT/CAR-T (n=1). Ki-67 ≥30% and extra-nodal disease was present in 54% and 68% of pts, respectively. The median # of prior systemic regimens for CLL Parts 1 & 2 and CLL Part 3 (RR), was 2 (1-15) including auto-SCT (n=1), and 2 (1-6). Pts entered with Rai staging ≥ Grade 2 in 71% and 64%. Safety (MCL and CLL): Most frequent treatment emergent (TEAEs) (≥30%) for both MCL and CLL pts treated with Cirm/Ibr (N=80), (all grades; regardless of causality) included contusion & fatigue (both 40.0%), and diarrhea (37.5%). Most frequent (≥5%) Grade ≥3 TEAEs, regardless of causality included hypertension (10.0%), fatigue, neutropenia, pneumonia, and atrial fibrillation (all 6.3%), leukocytosis and anemia (both 5.0%). Grade ≥3 TEAEs of myelosuppression, regardless of causality, include anemia (5.0%), thrombocytopenia (1.3%), and neutropenia (6.3%). Most TEAEs in MCL or CLL pts were considered related by Investigator to Ibr alone 64% or 84% vs. Cirm alone 14.3% or 16%. Efficacy (MCL): The best response of 20 evaluable pts in Parts 1 & 2 included CR 35%, PR 45%, SD 10%, and 10% PD. At a median follow-up of 14.9 mos., the objective response rate (ORR), clinical benefit rate (CBR) and median duration of response (DOR) for overall, ≥30% Ki-67, and >1 prior systemic regimen subgroups, were 80%, 90% and (not reached) NR (95% CI: 11.9, NR), 81.8%, 81.8% and 13.8 (95% CI: 8.7, NR), and 90%, 100% and NR (95% CI: 8.7, NR). Responses occurred in all evaluable pts who received prior SCT+/- CAR-T (4CR, 2PR) or prior Ibr (2CR, 2PR). The median PFS (mPFS) for overall, pts achieving CR, and >1 prior systemic regimen subgroups were all NR with varying 95% CI: (16.5, NR), (0.03, NR), and (0.03, NR). Efficacy (CLL): The best response of 34 evaluable pts in Parts 1 & 2 included 94.1% ORR, 11.8% CR, 82.3% PR/PR-L, and 5.9% SD for a CBR of 100%. In Part 3, evaluable Cirm/Ibr TN (n=8) or RR (n=7) and Ibr TN (n=4) or RR (n=3) arms achieved 100% or 85.7% and 100% or 100% ORR, 12.5% or 0% and 0% or 0% CR, 87.5% or 85.7% and 100% or 100% PR/PR-L, 0% or 14.3% and 0% or 0% SD. No pts had PD as best response. All pts had a CBR of 100%. For Parts 1 & 2, at a median follow-up of 24.8 mos., the DOR for overall and >1 prior systemic regimen subgroups, was NR (8.3, 35.9) and NR (12.0, 29.6). In Part 3, at a median follow-up of 14.7 mos., the DOR for TN or RR Cirm/Ibr and Ibr arms is NR (7.7, 18.6) or NR (9.2, 14.8) and NR (11.2, 18.5) or NR (8.3, 14.2). The mPFS (Parts 1 & 2) for overall, pts achieving CR, and >1 prior systemic regimen subgroups were NR (9.1, 35.8), NR (95% CI: 22.5, NR), and NR (9.1, 35.2). In Part 3, mPFS for TN or RR Cirm/Ibr and Ibr arms is all NR. Conclusions: Cirm/Ibr is well-tolerated. ORR, CR, DOR, and mPFS were similar across all subgroups of MCL and CLL pts regardless of number of prior systemic regimens or poor risk factors. Striking responses were observed in patients with MCL as evidenced by a mPFS that was NR (95% CI: 16.5, NR), CR of 35%, and a DOR of NR (95% CI: 11.9, NR) within the study period. These data compare very favorably to the mPFS of 12.8 mos, CR of 20%, and a DOR of 18.6 mos., reported for Ibr alone (Rule 2017). For CLL pts treated with Cirm/Ibr, results continue to be encouraging as they mature. The study is ongoing, with MCL enrollment expanded to include Cirm + Ibr in pts who have had an inadequate response to an Ibr regimen, or who are refractory to approved BTKi agents. Figure 1 Figure 1. Disclosures Lee: Oncternal: Research Funding; Takeda: Research Funding; Celgene: Research Funding; Seagen: Research Funding; BMS: Honoraria, Research Funding; Aptitude Health: Honoraria; Guidepoint: Honoraria; Century Therapeutics: Consultancy; Pharmacyclics: Research Funding; Janssen: Honoraria. Choi: Abbvie: Other: Institution: Research Grant/Funding; Pharmacyclics: Other: Institution: Research Grant/Funding; Oncternal: Other: Institution: Research Grant/Funding; Velosbio: Other: Institution: Research Grant/Funding; Merck: Other: Institution: Research Grant/Funding; Geron: Other: Institution: Research Grant/Funding. Siddiqi: Celgene: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kite Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Speakers Bureau; Oncternal: Research Funding; TG Therapeutics: Research Funding. Wierda: Acerta Pharma Inc.: Research Funding; Pharmacyclics LLC, an AbbVie Company: Research Funding; AstraZeneca: Research Funding; Cyclacel: Research Funding; Karyopharm: Research Funding; Xencor: Research Funding; Oncternal Therapeutics, Inc.: Research Funding; KITE Pharma: Research Funding; Miragen: Research Funding; Janssen: Research Funding; Gilead Sciences: Research Funding; Juno Therapeutics: Research Funding; Genentech: Research Funding; GSK/Novartis: Research Funding; Sunesis: Research Funding; Loxo Oncology, Inc.: Research Funding; Genzyme Corporation: Consultancy; AbbVie: Research Funding. Tuscano: BMS: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; Acrotech: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Abbvie: Research Funding. Leslie: Abbvie: Consultancy, Honoraria; PCYC/Janssen: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy, Honoraria, Speakers Bureau; Karyopharm Therapeutics: Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; BeiGene: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy; Celgene/BMS: Consultancy, Honoraria, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Speakers Bureau; Epizyme: Consultancy, Honoraria, Speakers Bureau; Seagen: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy. Breitmeyer: Oncternal Therapeutics: Current Employment, Membership on an entity's Board of Directors or advisory committees. Yazji: Oncternal Therapeutics: Current Employment. Wang: Oncternal Therapeutics: Current Employment. Wang: OMI: Honoraria; Moffit Cancer Center: Honoraria; Chinese Medical Association: Honoraria; Newbridge Pharmaceuticals: Honoraria; DTRM Biopharma (Cayman) Limited: Consultancy; InnoCare: Consultancy, Research Funding; Scripps: Honoraria; Mumbai Hematology Group: Honoraria; VelosBio: Consultancy, Research Funding; BioInvent: Research Funding; Hebei Cancer Prevention Federation: Honoraria; Epizyme: Consultancy, Honoraria; Anticancer Association: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Lilly: Research Funding; Physicians Education Resources (PER): Honoraria; Dava Oncology: Honoraria; Clinical Care Options: Honoraria; Molecular Templates: Research Funding; BeiGene: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Research Funding; Acerta Pharma: Consultancy, Honoraria, Research Funding; Imedex: Honoraria; Juno: Consultancy, Research Funding; Celgene: Research Funding; Genentech: Consultancy; Loxo Oncology: Consultancy, Research Funding; Kite Pharma: Consultancy, Honoraria, Research Funding; Miltenyi Biomedicine GmbH: Consultancy, Honoraria; The First Afflicted Hospital of Zhejiang University: Honoraria; Bayer Healthcare: Consultancy; BGICS: Honoraria; CAHON: Honoraria; Oncternal: Consultancy, Research Funding; CStone: Consultancy. Jamieson: Forty Seven Inc.: Patents & Royalties. Kipps: Genentech-Roche: Consultancy; Gilead Sciences: Consultancy, Honoraria, Other, Speakers Bureau; Janssen: Consultancy, Honoraria, Other, Research Funding, Speakers Bureau; Roche: Honoraria, Other; MD Anderson Cancer Center: Research Funding; Velos: Research Funding; CRIM: Research Funding; Indy Hematology Review: Other; TG Therapeutics: Other; Verstem: Other, Speakers Bureau; University of California, San Diego: Current Employment; Pharmacyclics/AbbVie: Honoraria, Research Funding; Breast Cancer Research Foundation: Research Funding; SCOR - The Leukemia and Lymphoma Society: Research Funding; National Cancer Institute/NIH: Honoraria, Research Funding; Genentech/Roche: Honoraria; European Research Initiative on CLL (ERIC): Honoraria; Genetech: Honoraria, Other; Celgene: Consultancy, Honoraria, Other, Research Funding; Bionest Partner: Other; DAVA Pharmaceuticals: Speakers Bureau; DAVAOncology: Consultancy, Honoraria, Other; AbbVie: Consultancy, Honoraria, Other, Speakers Bureau; Oncternal Therapeutics, Inc.: Current holder of stock options in a privately-held company, Other: Stock or other ownership, Patents & Royalties: Cirmtuzumab was developed by Thomas J. Kipps in the Thomas J. Kipps laboratory and licensed by the University of California to Oncternal Therapeutics, Inc., which provided stock options and research funding to the Thomas J. Kipps laboratory., Research Funding; Moores Cancer Center: Current Employment; MedImmune Inc: Research Funding; GlaxoSmithKline: Research Funding; Gilead Sciences, Inc.: Honoraria, Research Funding; Genentech, Inc.: Honoraria, Research Funding, Speakers Bureau; Pharmacyclics LLC, an Abbvie Company: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Celgene Corporation: Consultancy, Honoraria, Research Funding; Abbott Laboratories: Consultancy, Research Funding.

Introduction: Diffuse large B-cell lymphomas (DLBCL) transformed from indolent B-cell non-Hodgkin lymphomas (B-NHL) or Richter transformation (RT) from chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) are associated with a poor prognosis, particularly in patients (pts) with relapsed/refractory (RR) disease. PD-1/PD-L1 blockade has produced anti-tumor responses in pts with lymphoma; however, the response rate in pts with DLBCL is low. Preclinical data suggest that some "immunogenic" chemotherapies alter the tumor microenvironment and act synergistically with checkpoint blockade to improve anti-tumor responses. We evaluated the addition of the PD-L1 inhibitor, atezolizumab, to immunogenic chemoimmunotherapy, rituximab with gemcitabine and oxaliplatin (R-GEMOX) in pts with RR transformed DLBCL. Methods: Pts with DLBCL transformed from indolent B-NHL or RT from CLL that had received ≥ 1 prior regimen with ECOG performance status ≤ 2, and adequate organ and hematologic function were eligible for this phase 1 study. Two cohorts were enrolled, one for pts with DLBCL transformed from follicular lymphoma (FL) and another for pts with non-FL transformed DLBCL, including RT. R-GEMOX was administered without atezolizumab on C1D1, R-GEMOX+Atezo was given subsequently (Days 1+15 of 28 day cycles) for a maximum of 6 doses. Pts in CR could proceed to R+atezo q3w maintenance for up to 2 years. Pts could proceed to hematopoietic cell transplantation (HCT) without subsequent maintenance at the discretion of the treating MD. A safety lead-in (6 pts, any cohort) with dose-limiting toxicity (DLT) evaluation (28-day period, after 1 st dose of atezo) at dose level (DL) 1 (rituximab 375mg/m2, gemcitabine 1000mg/m2, oxaliplatin 100mg/m2, atezolizumab 840mg, with de-escalation dose level available) was enrolled to confirm the recommended phase 2 dose (RP2D). After confirmation of the RP2D, expansion will continue until enrollment of n=14 transformed FL and n=10 non-FL transformed DLBCL. Responses were assessed by investigators by PET-CT (after C2, C4, and then q12weeks) according to the 2014 Lugano Classification. The primary endpoint was safety and determination of the RP2D. Results: 23 pts were enrolled, 22 were evaluable for response and adverse events (AEs), 1 is too early. Baseline characteristics are summarized in Table 1. 1/6 pts had a DLT related to atezolizumab during safety lead-in: grade (G) 4 Stevens-Johnson syndrome leading to death. DL1 was the RP2D. 2 pts were replaced during safety lead-in due to progressive disease (PD) prior to completing DLT evaluation. The most common AEs with R-GEMOX+Atezo (n=22) were fatigue (50%), elevated transaminases (45%), thrombocytopenia (45%), nausea/vomiting (41%), diarrhea (32%), fever (32%), hypertension (HTN) (27%), and neutropenia (27%). Common G3-4 AEs included lymphopenia (n=4), neutropenia (n=4), HTN (n=3), leukopenia (n=3), thrombocytopenia (n=3). Among 7 pts who proceeded to maintenance R-atezo, the most common AEs were fatigue (n=4) and HTN (n=3). There were 2 deaths related to study therapy, the pt with SJS and 1 pt with infusion reaction leading to respiratory failure who also had PD with both factors likely contributing to death. In addition, 1 pt had both sepsis and PD and died during maintenance, considered possibly related to treatment. 7 deaths were unrelated to treatment, including 1 from complications after autologous HCT, and 6 after PD. 5 pts remain on treatment; 17 pts are off treatment. Reasons for study discontinuation include: insufficient response/PD (n=12), HCT (n=2), death due to toxicity (n=2), and G3 neuropathy during maintenance (n=1). Among the 22 pts, the ORR was 50% and CR rate was 29%. The 9 pts with transformed FL had an ORR of 67% and CR rate of 33%. The 13 pts with non-FL transformed DLBCL/RT had an ORR of 38% and CR rate of 23%. Of 9 pts with RT there was 1 CR and 1 PR while all 3 pts with transformed marginal zone lymphoma responded (2 CR, 1 PR). Among responders (n=11), the median duration of response was not reached (Figure 1). Of the 6 pts with CR, 2 proceeded to HCT, and 4 had ongoing CR lasting 30.7+ months (mo), 13.9+ mo, 6.8+ mo, 5.0+ mo. Of the 5 patients with PR, 1 pt died of SJS without PD, PR lasted 3 and 4 mo in 2 patients (PD), and 2 pts have ongoing response (0.5+ and 2.0+ mo). Conclusions: R-GemOx+Atezo was tolerable and produced objective responses in patients with transformed DLBCL/RT, with all pts in CR having ongoing response. Figure 1 Figure 1. Disclosures Herrera: Gilead Sciences: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Tubulis: Consultancy; Takeda: Consultancy; Merck: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Kite, a Gilead Company: Research Funding; AstraZeneca: Consultancy, Research Funding; Karyopharm: Consultancy; Seagen: Consultancy, Research Funding. Allen: Epizyme: Consultancy; Kyowa Kirin: Consultancy; Secure Bio: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy. Popplewell: Hoffman La Roche: Other: Food; Novartis: Other: Travel; Pfizer: Other: Travel. Shouse: Beigene: Honoraria; Kite Pharma: Speakers Bureau. Siddiqi: AstraZeneca: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Oncternal: Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kite Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Speakers Bureau; TG Therapeutics: Research Funding. Danilov: Gilead Sciences: Research Funding; Pharmacyclics: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; TG Therapeutics: Consultancy, Research Funding; Takeda Oncology: Research Funding; Genentech: Consultancy, Honoraria, Research Funding; SecuraBio: Research Funding; Bayer Oncology: Consultancy, Honoraria, Research Funding; Astra Zeneca: Consultancy, Honoraria, Research Funding; Bristol-Meyers-Squibb: Honoraria, Research Funding; Rigel Pharm: Honoraria. Tuscano: Seattle Genetics: Research Funding; Bristol Myers Squibb: Research Funding; Takeda: Research Funding; Acrotech: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Abbvie: Research Funding. OffLabel Disclosure: Atezolizumab is not approved for the treatment of aggressive B-cell non-Hodgkin lymphoma

Background Relapsed/refractory (R/R) acute myeloid leukemia (AML) remains a challenge to cure. Prior studies of hypomethylating agent (HMA) decitabine (DEC), proteasome inhibitor bortezomib (BTZ), and anthracycline (AC) pegylated liposomal doxorubicin (PLD) monotherapy, as well as DEC + BTZ and BTZ + PLD regimens, have demonstrated safety and modest activity in R/R AML. Inhibition of NF-κB signaling by BTZ and DEC could prevent AC resistance resulting from NF-κB activity. Thus, we hypothesized that the DEC + BTZ + PLD (DBP) regimen would have activity in R/R AML. Methods We performed a phase II trial of DBP, with a safety lead-in cohort, in patients aged 18-90 with R/R AML. The original protocol called for 1-4 28-day (D) cycles of induction with intravenous (IV) DEC 20mg/m 2 on D1-10, subcutaneous (SQ) BTZ 1.3mg/m 2 on D1, 4, 8, and 11, and IV PLD 40mg/m 2 on D4. Dose-limiting toxicity (DLT) of grade 3 peripheral neuropathy (G3 PN) in the first 2 patients led to a revised schedule of BTZ on D5, 8, 12, and 15 and PLD on D12, eliminating simultaneous DBP dosing on any 1 day. Patients achieving a bone marrow blast count Results Ten patients were enrolled from May 2016 to February 2018, after which the sponsor closed the protocol. Median age was 57 years [range 27-69]. Patients were 50% female, 60% White, 10% African American/Black, 30% other/mixed race, and 40% Hispanic/Latino, with median baseline ECOG score of 1 [0-1] and median 2 [1-3] lines of prior therapy. Sixty percent had de novo and 40% had secondary disease. By WHO subtype, 30% had AML with MRC, 20% NPM1 mutation, 10% inv(3), 10% therapy-related, and 30% not otherwise specified. European LeukemiaNet 2017 risk was favorable in 20%, intermediate in 40%, and adverse in 40%. Median number of cycles completed was 2 [1-7] with a median time on study of 100.5 days [35-678]. One patient achieved CR and 2 achieved CRi for an ORR of 30%. An additional patient likely had a CR with All patients discontinued treatment. Reasons included BMT (40%), AE (30%), progression (20%) and insurance loss (10%). Half planned to bridge to BMT as next-line therapy following study treatment. When taken off study, 50% were alive while 20% had died from AML complications, 20% from graft-versus-host-disease post-BMT, and 10% after relapse post-BMT. Median OS was 6.67 months (95% confidence interval [CI] 6.07 to not reached [NR]). Median EFS was 3.22 months (95% CI 1.50 to NR), with a maximum EFS of 16.93 months. Following G3 PN in the first 2 patients, no DLTs occurred on the modified regimen. Seventy percent of patients experienced at least possibly related G3+ AEs or serious AEs (SAEs). Of the 22 related G3+ AEs, anemia and decreased platelet count were seen in 50% and dizziness in 20%. Of the 22 related SAEs, anorexia, fatigue, PN, febrile neutropenia, and bacteremia were most common, each occurring in 20%. Conclusion The DBP triplet demonstrated preliminary anti-AML activity in a R/R AML patient cohort. Staggered dosing was better tolerated than simultaneous DBP. DBP may serve as an effective bridge to BMT for some patients. This study supports further evaluation of DBP, or related combinations, in R/R AML. Disclosures Rosenberg: Takeda, Janssen: Speakers Bureau. Abedi: Seattle Genetics: Speakers Bureau; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Abbvie: Speakers Bureau. Tuscano: BMS, Seattle Genetics, Takeda, Achrotech, Genentech, Pharmacyclics, Abbvie: Research Funding. Jonas: AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy; 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie: Other: Travel reimbursement. OffLabel Disclosure: Bortezomib is FDA-approved for the treatment of multiple myeloma in patients who have already been treated with 2 lines of prior therapy and progressed on the most recent therapy. Decitabine is indicated for treatment of patients with myelodysplastic syndromes. Doxorubicin is approved in AML among other cancers.

Introduction: While previous studies propose pesticide exposure to be a risk factor for non-Hodgkin lymphoma (NHL) development, results are inconclusive. In addition, the impact of pesticide exposure on NHL survival is not well-established. Therefore, we identified NHL patients from the California Cancer Registry and linked these patients with the statewide pesticide use reporting database to determine the impact of pesticide exposure on NHL-related incidence and outcomes. Methods: Using the California Cancer Registry, we identified patients with a first primary diagnosis of NHL from 2010-2016 and linked these patients with CalEnviroScreen 3.0 to obtain production agriculture pesticide exposure to 70 chemicals from the state mandated Pesticide Use Reporting (PUR) by census tract from 2012-2014. In addition, data from PUR was integrated into a geographic information system that employs land use data to estimate cumulative exposure to specific pesticides previously associated with NHL (glyphosate, organophosphorus, carbamate, phenoxyherbicide and 2,4-dimethylamine salt) between 10 years prior up to 1 year after NHL diagnosis. SEER*Stat software was used to calculate NHL subtype incidence rates by census tract pesticide use level. Multivariable cox proportional hazards regression models were used to evaluate the impact of total pesticide exposure from CalEnviroScreen 3.0 and individual pesticide exposure from geographic land use data on lymphoma-specific and overall survival. Results: Among 35,808 NHL patients identified, 44.2% were exposed to pesticide in their census tract of residence. Pesticide exposure was higher in Hispanic/Latino (46.5%) and non-Hispanic white (45.6%) then Asian/Pacific Islander (37.2%) and African American (34.9%) patients with NHL. Glyphosate, organophosphorus, carbamate, phenoxyherbicide and 2,4-dimethylamine salt exposure was reported in 34.1%, 26.0%, 10.6%, 14.0% and 12.8% of NHL patients, respectively. Pesticide exposure was not associated with increased NHL incidence by NHL subtype or subgroups defined by sociodemographic factors. Total pesticide exposure at time of diagnosis was not associated with lymphoma-specific or overall survival. In addition, no association was consistently found between glyphosate, organophosphorus, carbamate, phenoxyherbicide and 2,4 dimethylamine salt exposure and lymphoma-specific or overall survival. Conclusion: In this large population-based study of neighborhood agricultural pesticide exposure, pesticide exposure was noted to be prevalent among patients diagnosed with NHL, with high pesticide exposure particularly observed in Hispanics/Latinos and non-Hispanic whites. However, pesticide exposure was not consistently associated with increased NHL incidence or worse NHL lymphoma-specific or overall survival. Disclosures Poh: Acrotech: Honoraria; Incyte: Research Funding; Morphosys: Consultancy. Tuscano: BMS: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding; Acrotech: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Abbvie: Research Funding.

Introduction: Cirmtuzumab (Cirm) is a high-affinity humanized monoclonal antibody designed to inhibit the tumor promoting activity of ROR1. In this study, we examined the safety and efficacy of Cirm in combination with ibrutinib (Ibr) in patients (pts) with MCL or CLL. ROR1 is an onco-embryonic tyrosine kinase-like receptor that is found at high levels on the cell surface of many hematologic and solid cancers. Activation of ROR1 by binding its ligands such as Wnt5a results in increased intracellular signaling, tumor growth and survival, enhanced cancer cell stemness and epithelial mesenchymal transition. Methods: Pts with relapsed or refractory (RR) MCL or treatment naïve (TN) or RR CLL were enrolled and treated in separate groups. In Part 1 Dose Escalation (DE), groups of MCL and CLL pts received Cirm IV q2wks x5 doses then q4wks at assigned doses of 2-16 mg/kg, and in CLL, additional fixed dose levels of 300 or 600 mg were evaluated. The safety and PK of single-agent Cirm was assessed during the first 28 days, and then Ibr was started at 560 mg/day PO for MCL or 420 mg/day PO for CLL. After reviewing the safety and PK data from Part 1, a recommended regimen of fixed dose Cirm 600 mg IV q2wks x3 then q4wks plus Ibr starting D0 was chosen for use in Parts 2 and 3. In Part 3, CLL pts (only) were randomized to either Cirm/Ibr vs. Ibr alone Results: As of April 30, 2020, 12 evaluable MCL pts were enrolled into Part 1 DE. Of these pts, 83% (10) had received ≥ 2 separate prior treatment regimens. In CLL, 34 pts (12 TN and 22 RR pts) enrolled into Part 1 DE (n= 18) or Part 2 Expansion (n= 16). At least 79% of CLL pts in Parts 1 and 2 were high risk as determined by unmutated IGHV, del17p, and/or del11q. Safety: For both MCL and CLL, the most common adverse events (AEs) considered at least possibly related to Cirm alone were grade 1/2 (e.g. fatigue, 6%) with no dose limiting toxicities or discontinuations. The combination of Cirm plus Ibr was well tolerated, with no new or accentuated AEs compared to the known safety profile of Ibr alone. Cirm may be lowering the rates of certain AEs normally seen with Ibr; for example, neutropenic events were 8 mos after stopping all therapy. At a median follow-up of 12.8 mos, 100% of CLL pts were free of disease progression and 82% remained on study. CLL cells collected after the first 28 days of treatment showed a decrease in stemness signature (Choi et al, Cell Stem Cell 2019), with similar reductions seen with single agent Cirm or Cirm + Ibr. Additional pts have been enrolled into Part 2 Expansion MCL and into Part 3 CLL. Early data from these arms are not yet available and will be reported later. Conclusions: Cirmtuzumab in combination with ibrutinib is a well-tolerated and active regimen for RR MCL and TN or RR CLL. The 58% CR/CMR rate for MCL compares favorably to published data with single agent Ibr of 27% (Rule, et al. Haematologica 2019) and it is encouraging that responses occurred in heavily pretreated pts, including those with high Ki-67 expression. In CLL, the high ORR and interim PFS are encouraging; the significance of these observations will be determined with longer follow-up. These data support the continued investigation of this regimen in ROR1-expressing hematologic and solid malignancies. This study is ongoing, and due to the high CR rate in MCL pts, the number of pts to be enrolled in the Part 2 Expansion will be increased to further characterize the safety and efficacy of this combination. Disclosures Lee: Bristol-Myers Squibb: Consultancy, Research Funding; Aptitude Health: Speakers Bureau; Celgene: Research Funding; Guidepoint Blogal: Consultancy; Oncternal Therapeutics: Research Funding; Seattle Genetics: Research Funding; Takeda: Research Funding. Choi:Pharmacyclics/Abbvie: Research Funding; Genentech: Consultancy. Siddiqi:Juno Therapeutics, Pharmacyclics LLC, an AbbVie Company, AstraZeneca, Celgene, Kite Pharma, and BeiGene: Consultancy; Pharmacyclics LLC, an AbbVie Company, Seattle Genetics, Janssen, and AstraZeneca: Speakers Bureau; BeiGene: Other: DMC member; AstraZeneca: Other: Travel/accommodations/expenses; Astrazenca: Membership on an entity's Board of Directors or advisory committees; PCYC: Membership on an entity's Board of Directors or advisory committees; Juno: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics LLC, an AbbVie Company, Juno Therapeutics, KITE Pharma, AstraZeneca, TG Therapeutics, Celgene, Oncternal, and BeiGene: Research Funding. Barrientos:Oncternal Therapeutics: Research Funding; Gilead: Consultancy; AstraZeneca: Consultancy; Bayer: Consultancy; Sandoz: Consultancy; Janssen: Honoraria; Genentech: Consultancy. Lamanna:Octapharma: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bei-Gene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Institutional research grants, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Institutional research grants, Research Funding; Juno: Other: Institutional research grants, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; MingSight: Other: Institutional research grants, Research Funding; Oncternal, Verastem, TG Therapeutics: Other: Institutional research grants, Research Funding; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Institutional research grants, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Institutional research grants, Research Funding; Columbia University Medical Center: Current Employment; Loxo: Research Funding. Tuscano:Abbvie: Research Funding; Pharmacyclics: Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria; Seattle Genetics: Honoraria; Novartis: Research Funding; Spectrum: Research Funding; Takeda: Research Funding; Genentech: Research Funding. Leslie:KitePharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; Karyopharm: Honoraria, Speakers Bureau; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Speakers Bureau; BeiGene: Honoraria, Speakers Bureau; Celgene: Speakers Bureau; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Ianopulos:Oncternal Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Breitmeyer:Oncternal Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties. Hsu:Oncternal Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company; Immune Design: Ended employment in the past 24 months. Wang:Beijing Medical Award Foundation: Honoraria; Lu Daopei Medical Group: Honoraria; MoreHealth: Consultancy; OMI: Honoraria, Other: Travel, accommodation, expenses; Targeted Oncology: Honoraria; Loxo Oncology: Consultancy, Research Funding; Pulse Biosciences: Consultancy; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Juno: Consultancy, Research Funding; BioInvent: Research Funding; VelosBio: Research Funding; Acerta Pharma: Research Funding; InnoCare: Consultancy; Oncternal: Consultancy, Research Funding; Nobel Insights: Consultancy; Guidepoint Global: Consultancy; Dava Oncology: Honoraria; Verastem: Research Funding; Molecular Templates: Research Funding; OncLive: Honoraria; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding. Jamieson:Bristol-Myers Squibb: Other; Forty Seven Inc: Patents & Royalties. Kipps:VelosBio: Research Funding; Pharmacyclics/ AbbVie, Breast Cancer Research Foundation, MD Anderson Cancer Center, Oncternal Therapeutics, Inc., Specialized Center of Research (SCOR) - The Leukemia and Lymphoma Society (LLS), California Institute for Regenerative Medicine (CIRM): Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Research Funding; Ascerta/AstraZeneca, Celgene, Genentech/F. Hoffmann-La Roche, Gilead, Janssen, Loxo Oncology, Octernal Therapeutics, Pharmacyclics/AbbVie, TG Therapeutics, VelosBio, and Verastem: Membership on an entity's Board of Directors or advisory committees; Oncternal Therapeutics, Inc.: Other: Cirmtuzumab was developed by Thomas J. Kipps in the Thomas J. Kipps laboratory and licensed by the University of California to Oncternal Therapeutics, Inc., which provided stock options and research funding to the Thomas J. Kipps laboratory, Research Funding.

Background:T-follicular helper (TFH) cells are a novel CD4+ T-cell subset that participates in germinal center maintenance/proliferation. Proliferation of TFH is a postulated mechanism of pathogenesis for T-cell lymphomas (AITL, PTCL and others). The inducible T-cell costimulator (ICOS) is highly expressed in TFHand hence in AITL, PTCL FH type, and some cutaneous T cell lymphomas (CTCL) and follicular lymphomas (FL). MEDI-570 is a human afucosylatedIgG1 kappa monoclonal antagonistic antibody directed against ICOS, which binds to and eliminates ICOS expressing cells in preclinical in vivo models. We investigate the safety, pharmacokinetics (PK) and clinical activity of ICOS blockade by MEDI-570 in T-cell lymphomas. Methods: NCI-9930 is a Phase I study of MEDI-570 in R/R malignant lymphomas. It is a 3+3 study design that evaluated 5 dose levels . MEDI-570 was administered intravenously (IV) every 3 weeks for 12 cycles. Eligibility criteria included: age >18 years, ECOG 200 cells/uL (>100 for AITL). Primary endpoints are safety of MEDI-570, dose limiting toxicities (DLT)s and its recommended phase 2 dose (RP2D). Secondary endpoints include: pharmacokinetics (PK), overall response rate (ORR) based on Lugano classification and progression-free survival (PFS). Exploratory endpoints include various correlative studies. This study is supported by the National Cancer Institute Experimental Therapeutics Clinical Trials Network (ETCTN) and Early Drug Development Opportunity Program (EDDOP) (NCT02520791). Results: As of June 2020, the dose escalation phase has been completed. Patients were enrolled and evaluable for safety and efficacy. Median age is 63 (range: 29-80), female/male ratio=5/13, histologic types consisted in AITL (n= 12, 71%), PTCL NOS (n=3, 18%) and CTCL (n=2, 12%). The median number of prior therapies were 7.5 (1 - 16), stage III/IV in 83%, prior autologous HCT in 18%. There were 4 partial remissions (PR) and 7 with stable disease (SD), all patients with AITL. Two patients (1 PR and 1 SD) remain on treatment. One patient completed treatment and remains in a stable PR for over a year without further treatment. One patient in PR underwent allogeneic hematopoietic transplantation (HCT) and remains in remission. The most common grade 3/4 AEs were decreased CD4+ T-cells as expected anemia (12%), hypophosphatemia (12%), thrombocytopenia (6%), infusion related reactions (6%). No DLTs were reported, and the maximum tolerated dose was not established. Initial PK analyses demonstrated that MEDI-570 systemic exposure increased in a dose-dependent manner, and a RP2D was determined. Peripheral blood flow cytometry analysis of T-cell subsets showed that MEDI-570 caused a rapid and sustained decrease in CD4+ T-cells. It also resulted in reductions in circulating of certain ICOS+ T-cells, especially on days 7-21 post treatment. Conclusion: MEDI-570 was safe, well tolerated and showed promising clinical activity in poor-risk refractory and heavily pretreated AITL. A RP2D was established. MEDI-570 results in sustained reduction of the targeted ICOS+T lymphocytes. The study continues enrolling in the expansion phase. Disclosures Chavez: Morphosys: Consultancy, Speakers Bureau; Merck: Research Funding; Bayer: Consultancy; BeiGene: Speakers Bureau; Karyopharm: Consultancy; AbbVie: Consultancy; Genentech: Speakers Bureau; AstraZeneca: Speakers Bureau; Gilead: Consultancy; Verastem: Consultancy; Epizyme: Speakers Bureau; Celgene: Consultancy; Novartis: Consultancy; Kite, a Gilead Company: Consultancy, Speakers Bureau; Pfizer: Consultancy. William:Dova: Research Funding; Seattle Genetics: Research Funding; Incyte: Research Funding; Merck: Research Funding; Kyowa Kirin: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Guidepoint Global: Consultancy. Brammer:Celgene Corporation: Research Funding; Seattle Genetics, Inc.: Speakers Bureau. Smith:Pharmacyclics: Research Funding; Genentech/Roche: Consultancy, Other: Support of parent study and funding of editorial support, Research Funding; Acerta: Research Funding; BMS: Consultancy; Karyopharm: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; FortySeven: Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy. Prica:astra zeneca: Honoraria; seattle genetics: Honoraria; Gilead: Honoraria. Zain:Kyowa Kirlin: Research Funding; Mundai Pharma: Research Funding; Seattle Genetics: Research Funding. Glenn:Genentech: Research Funding. Mehta-Shah:Verastem: Research Funding; Karyopharm Therapeutics: Consultancy; Kyowa Kirin: Consultancy; Innate Pharmaceuticals: Research Funding; Celgene: Research Funding; Genetech: Research Funding; C4 Therapeutics: Consultancy; Bristol Myers-Squibb: Research Funding. Boutrin:Astrazeneca: Current Employment, Current equity holder in private company. Zhao:Astrazeneca: Current Employment, Current equity holder in private company. Cheng:Astrazeneca: Current Employment, Current equity holder in private company. Standifer:Astrazeneca: Current Employment, Current equity holder in private company. Carlesso:Astrazeneca: Current Employment, Current equity holder in private company. Siu:Shatthucks: Research Funding; Symphogen: Consultancy, Research Funding; Tessa: Consultancy; Treadwell Therapeutics: Consultancy, Current Employment; Pfizer: Research Funding; Voronol: Consultancy; Rubius Therapeutics: Consultancy; Abbvie: Research Funding; Agios: Current equity holder in publicly-traded company; Arvinas: Consultancy; Astellas: Research Funding; AstraZeneca: Consultancy, Research Funding; Bayer: Research Funding; Boerhinger-Ingelheim: Research Funding; Bristol-Myers Squibb: Research Funding; Glaxo Smith Kline: Research Funding; Intensity Therapeutics: Research Funding; Navire: Consultancy; Novartis: Research Funding; Oncorus: Consultancy; Mirati: Consultancy, Research Funding; Roche/Genentech: Consultancy; Relay Therapeutics: Consultancy; Roche: Consultancy; Merck: Consultancy.

Purpose: Based on the potential for ipilimumab (I) to augment T-cell activation, we hypothesize that ipilimumab would augment the efficacy of rituximab (R) in patients with relapsed/refractory (R/R) CD20+non-Hodgkin's lymphoma (NHL). This phase I study aimed to identify a recommended phase 2 dose, document toxicities, and preliminarily assess efficacy and potential predictive biomarkers. Patients and Methods: Thirty-three patients with R/R CD20+B-cell lymphoma received R at 375 mg/m2weekly for 4 weeks and I at 3 mg/kg on day 1 and every 3 weeks for four doses. Responding patients went on to maintenance with each agent given every 12 weeks. To facilitate correlative analysis, the expansion phase randomized patients to simultaneous R+I versus R with I delayed 2 weeks. Results: Toxicity was manageable; no dose-limiting toxicity was observed at the doses studied. When considering the entire cohort, efficacy was modest, with an objective response rate (ORR) of 24% and median progression-free survival (PFS) of 2.6 months. However, in follicular lymphoma patients, the ORR was 58% with a median PFS of 5.6 months. The randomized comparison of R with R+I demonstrated that R+I resulted in more effective B-cell depletion (BCD). Both B-cell depletion and the ratio of CD45RA−regulatory T cell (Treg) to Treg were associated with response at all time points. Conclusions: The combination of R+I has manageable toxicity and encouraging efficacy in R/R follicular lymphoma. The ratio of CD45RA−Tregs to total Tregs, and peripheral BCD should be studied further as potential predictors of response.

The aryl hydrocarbon receptor (AhR) is known for mediating the toxicity of environmental pollutants such as dioxins and numerous dioxin-like compounds, and is associated with the promotion of various malignancies, including lymphoma. The aryl hydrocarbon receptor repressor (AhRR), a ligand-independent, transcriptionally inactive AhR-like protein is known to repress AhR signaling through its ability to compete with the AhR for dimerization with the AhR nuclear translocator (ARNT). While AhRR effectively blocks AhR signaling, several aspects of the mechanism of AhRR&rsquo, s functions are poorly understood, including suppression of inflammatory responses and its putative role as a tumor suppressor. In a transgenic mouse that overexpresses AhRR (AhRR Tg) we discovered that these mice suppress 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)- and inflammation-induced tumor growth after subcutaneous challenge of EL4 lymphoma cells. Using mouse embryonic fibroblasts (MEF) we found that AhRR overexpression suppresses the AhR-mediated anti-apoptotic response. The AhRR-mediated inhibition of apoptotic resistance was associated with a suppressed expression of interleukin (IL)-1&beta, and cyclooxygenase (COX)-2, which was dependent on activation of protein kinase A (PKA) and the CAAT-enhancer-binding protein beta (C/EBP&beta, ). These results provide mechanistic insights into the role of the AhRR to suppress inflammation and highlight the AhRR as a potential therapeutic target to suppress tumor growth.

7556 Background: Cirmtuzumab (Cirm) is a humanized monoclonal antibody that inhibits the tumor promoting activity of ROR1 and had demonstrated additive/synergistic activity with many anti-cancer agents including ibrutinib (Ibr). Methods: Patients (Pts) with relapsed or refractory (RR) MCL or treatment naïve (TN) or RR CLL were enrolled. In Part 1 (Dose Escalation), doses of Cirm IV q2wks x5 then q4wks of 2-16 mg/kg and 300 or 600 mg were examined. Safety of Cirm alone was assessed during the first 28 days, then Ibr was started at approved doses for each indication. Cirm 600 mg IV q2wks x3 then q4wks in combination with Ibr starting day 0 was chosen as the recommended dosing regimen for use in Part 2 (Expansion) and Part 3 (CLL only, Cirm/Ibr vs. Ibr alone). Results: Twelve evaluable MCL pts were enrolled into Part 1, and 5 into Part 2. Median number of prior regimens was 2 (1-5), including pts relapsing after Ibr (4), auto-SCT (3), auto-SCT/ allo-SCT (1), auto-SCT/CAR-T (1). In CLL, 34 evaluable pts (12 TN and 22 RR) enrolled into Part 1 (18) or Part 2 (16). At least 74% of CLL pts in Parts 1 and 2 were high risk as determined by unmutated IGHV, del17p, and/or del11q. In Part 3, 22 evaluable pts received Cirm/Ibr (15) or Ibr (7). As of the 30OCT2020 safety cut-off for MCL and CLL, common TEAEs (all grades) included diarrhea (41%), contusion (39%), fatigue (39%), URI (31%), hypertension (25%) arthralgia (23%). Grade ≥3 neutropenia was 13% and thrombocytopenia 1%. There were no Cirm dose reductions or discontinuations for toxicity. Overall, Cirm did not appear to negatively impact the safety of Ibr. Efficacy (MCL): As of the 02FEB2021 efficacy cutoff, the best response of 17 evaluable pts in Parts 1 and 2 included an objective response rate (ORR) of 82%, 41% CR/CMR, 41% PR, 12% SD, and 6% PD. CR/CMR remain durable from 8-28+ mos. Most responses occurred rapidly after ̃3 mos of Cirm/Ibr. Notably, responses were achieved in all pts who received prior SCT+/- CAR-T (4CR, 1PR) or prior Ibr (2CR, 2PR). At a median follow-up of 14.6 mos, the median PFS (mPFS) had not been reached (NR) (95% CI: 17.5, NA). Efficacy (CLL): The best response of 34 evaluable pts in Parts 1 and 2 included 91% ORR, 3% CR, 88% PR/PR-L, 9% SD, 0% PD. In Part 3, both arms achieved 100% ORR (all PRs). At a median follow-up of 20.2 mos, the mPFS was NR (95% CI: NA, NA), and the PFS estimate at 24 months was 95% for R/R, and 87% for TN, respectively, for evaluable CLL pts receiving Cirm/Ibr. Conclusions: Cirm/Ibr is a well-tolerated, active regimen in both MCL and CLL. For MCL, the mPFS of NR (95% CI: 17.5, NA) and CRR (41%), with all CRs remaining without PD, compare favorably to mPFS of 12.8 mos (95% CI 8.5-16.6) and CRR (20%) reported for single agent Ibr (Rule 2017). For CLL, the high ORR and PFS are encouraging, particularly for RR CLL. The study is ongoing, with MCL enrollment expanded to study Cirm + Ibr in pts who have had a suboptimal response to an Ibr regimen, or who have failed other approved BTKi agents. Clinical trial information: NCT03088878.

Author(s): Esteghamat, Naseem; Keegan, Theresa; Brunson, Ann; Wun, Ted; Abedi, Mehrdad; Tuscano, Joseph; Hoeg, Rasmus; Jonas, Brian; Rosenberg, Aaron

In this study, the HB22.7 anti-CD22 mAb, was used for specific, targeted delivery of the potent anti-cancer agent, monomethyl auristatin E (MMAE) to non-Hodgkin lymphoma (NHL). MMAE was covalently coupled to HB22.7 through a valine-citrulline peptide linker (vc). Maleimide-functionalized vcMMAE (mal-vcMMAE) was reacted with thiols of the partially reduced mAb. Approximately 4 molecules of MMAE were conjugated to HB22.7 as determined by residual thiol measurement and hydrophobic interaction chromatography-HPLC (HIC-HPLC). HB22.7-vcMMAE antibody drug conjugate (ADC) retained its binding to Ramos NHL cells and also exhibited potent and specific in vitro cytotoxicity on a panel of B cell NHL cell lines with IC(50)s of 20 - 284 ng/ml. HB22.7-vcMMAE also showed potent efficacy in vivo against established NHL xenografts using the DoHH2 and Granta 519 cell lines. One dose of the ADC induced complete and persistent response in all DoHH2 xenografts and 90% of Granta xenografts. Minimal toxicity was observed. In summary, HB22.7-vcMMAE is an effective ADC that should be evaluated for clinical translation.

Lenalidomide, an immunomodulatory drug that the US Food and Drug Administration (FDA) approved for the treatment of multiple myeloma, 5q- myelodysplasia and mantle-cell lymphoma (MCL), has encouraging efficacy in other B-cell malignancies. Its unique mechanism of action is in part due to altering the tumor microenvironment and potentiating the activity of T and natural-killer (NK) cells. Impressive clinical activity and excellent tolerability allows broad applicability. Lenalidomide has been used in a wide range of B-cell malignancies for years, but in 2013, the FDA marked its approval as a single agent only in relapsed/refractory mantle-cell lymphoma. Perhaps most impressive is the efficacy of lenalidomide when combined with monoclonal antibodies. Impressive efficacy and toxicity profiles with the combination of lenalidomide and rituximab in B-cell lymphomas in both the upfront and relapsed/refractory setting may allow a shift in our current treatment paradigm in both indolent and aggressive non-Hodgkin lymphoma (NHL). This review will summarize the current data in the relapsed/refractory and front-line setting of NHL with single-agent lenalidomide as well as its use in combination with other agents.

Introduction Adults with newly diagnosed acute myeloid leukemia (AML) who receive intensive remission induction typically remain hospitalized until blood count recovery due to the high risk of infection and bleeding related to pancytopenia. This usually translates into at least 4 weeks of hospitalization, which can lead to reduced quality of life, increased risk of nosocomial infections, significant resource utilization and economic burden. Previous studies conducted at academic centers with large AML populations have suggested that outpatient management following induction chemotherapy is feasible and safe with close follow-up. These studies may have limited generalizability based on exceptional outpatient resources. Thus, this practice has not been widely adopted. To assess the feasibility of early patient discharge at our academic center which provides care for a smaller AML population, where we have a 6-days per week infusion center and hospitalize all AML patients undergoing induction until count recovery, we conducted a retrospective analysis of complications prior to blood count recovery in this patient population. Methods We identified patients ≥18 years with newly diagnosed non-APL AML admitted to the University of California, Davis Medical Center from 1/1/14 to 1/1/19 who received induction chemotherapy with cytarabine/daunorubicin (7+3) or a regimen of similar intensity with first interim bone marrow biopsy showing hypocellularity with Results Overall, 50 patients were identified; 42 (84%) received 7+3, 3 (6%) received FLAG and 5 (10%) received liposomal daunorubicin-cytarabine induction. Median age was 56 (range 25-81) years. ELN 2017 favorable, intermediate and adverse risk disease was observed in 18 (36%), 20 (40%) and 12 (24%) patients, respectively. Forty-nine (98%) patients with a negative interim marrow achieved a complete remission with first induction therapy. Forty-five (90%) patients had infectious complications at any time (Table 1), with 34 (68%) having infectious complications occurring prior to day 15 of induction. All patients with culture negative neutropenic fever prior to day 15 of induction as their only infectious complication had no further infectious complications throughout hospitalization although all received IV antibiotics until count recovery. Ten (20%) patients had hemorrhagic complications at any time (Table 1), with 9 (18%) having hemorrhagic complications occurring between day 15 of induction and discharge. Median platelet transfusion volume between days 15-21 and 22-discharge was 3.5 (range 1-18) and 0 (range 0-15) units, respectively. Three (6%) patients required ICU transfer. All ICU transfers occurred after day 14 of induction. One patient had hypoxic respiratory failure on admission and required transfer back to the ICU. Death prior to marrow recovery was observed in 1 patient (2%) due to subdural hemorrhage. Conclusion Intensive remission induction in hospitalized patients with newly diagnosed AML is associated with good efficacy and safety outcomes for patients with blast clearance on interim bone marrow biopsy. Although the rate of infectious complications was high, the majority debuted early during hospitalization and the rate of ICU transfers was low. All patients with culture negative neutropenic fever prior to day 15 of induction as their sole infectious complication who were treated with IV antibiotics had no further infectious complications throughout hospitalization. Hemorrhagic complications more commonly occurred later during hospitalization, although platelet transfusion requirements were manageable after day 15 of induction. These data suggest that at our institution, select patients receiving intensive remission induction and without infectious complications could be considered for early discharge and close outpatient follow-up after interim bone marrow biopsy showing hypoplasia. A prospective early discharge study to confirm these findings is being developed. Disclosures Poh: Acrotech: Honoraria. Tuscano:Spectrum: Research Funding; Novartis: Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Research Funding; Abbvie: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Honoraria. Rosenberg:Takeda: Speakers Bureau; Janssen: Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees. Jonas:Forma: Research Funding; F. Hoffmann-La Roche: Research Funding; Daiichi Sankyo: Research Funding; AROG: Research Funding; Accelerated Medical Diagnostics: Research Funding; Forty Seven: Research Funding; Jazz: Consultancy, Research Funding; Sigma Tau: Research Funding; Hanmi: Research Funding; Genentech/Roche: Research Funding; Pharmacyclics: Research Funding; Celgene: Consultancy, Research Funding; GlycoMimetics: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Treadwell: Consultancy; Tolero: Consultancy; Takeda: Consultancy; Pfizer: Research Funding; LP Therapeutics: Research Funding; Incyte: Research Funding; Amgen: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; AbbVie: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding.

8036 Background: ROR1 is an onco-embryonic tyrosine kinase receptor that is re-expressed at high levels on many hematologic and solid cancers but not on normal adult tissues. ROR1 binds Wnt5a, resulting in increased tumor growth and survival, cancer cell stemness and epithelial mesenchymal transition. Cirmtuzumab (Cirm) is a humanized monoclonal antibody designed to inhibit the tumor promoting activity of ROR1. In this study, we examined the safety and efficacy of Cirm in combination with ibrutinib (Ibr) in MCL or CLL. Methods: As of Jan 29, 2020, 12 pts with relapsed refractory (RR) MCL were enrolled into Part 1 Dose Escalation (DE). All MCL pts had stage 3/ 4 at original diagnosis, 25% had bulky tumor at study entry, 58% had intermediate/high risk MIPI scores and the majority (83%) had ≥ 2 prior regimens. 34 pts with CLL [12 treatment naïve (TN) and 22 RR pts] enrolled into Part 1 DE (n = 18) or Part 2 Expansion (n = 16). At least 79% of CLL pts were high risk as determined by unmutated IGHV, 17p/p53 loss, and/or del 11q. DE pts received Cirm IV q2wks x 3-5 doses then q4wks plus Ibr (starting D28). Following DE, Cirm 600mg IV q2wks x3 then q4wks plus Ibr (420mg/day CLL or 560mg/day MCL) was chosen for Expansion. Results: Safety : only grade 1/ 2 AEs were reported as possibly related to Cirm alone, whereas the safety profile attributed to Ibr or Ibr / Cirm was similar to published data, with no new or unexpected events. Efficacy for MCL: 83% ORR, 33% (4) CR, 50% (6) PR, 17% (2) SD. CRs were achieved at a median of 3.6 mos in heavily pretreated pts, including 2 with bulky disease > 5cm. Prior therapy of the 4 CR pts: 2 pts failed R-Ibr (7-10 mos) and R-hyperCVAD, 1 pt, auto-SCT and allo-SCT, 1 pt, auto-SCT and CAR-T. Efficacy for CLL : 88% ORR (92% TN, 86% RR), 3% (1) CR, 85% (22) PR/ (7) PR-L, 12% (4) SD. In addition, 3 PR pts with CLL met criteria for “Clinical CR, bone marrow biopsy not performed”. The pt achieving a CR had RR disease with del 11q; this pt remains in remission > 6 mos after stopping all therapy. At a median follow-up of 9.9 mos, 100% of CLL pts are free of disease progression and > 82% remain on study. Conclusions: Cirm in combination with Ibr is a well-tolerated and active regimen for RR MCL and TN or RR CLL. In this evaluation of 46 pts, the ORR and PFS continue to improve with longer follow-up and additional pts, supporting continued investigation of this regimen in ROR1 expressing tumors. This study is ongoing and enrolling an Expansion arm for MCL pts and an open-label randomized Phase 2 in CLL pts comparing Ibr alone to Cirm /Ibr. Clinical trial information: NCT03088878 .

Key Points Question Can the duration of phase 1 studies using either the 3 + 3 or rolling 6 designs be substantially reduced without exceeding the patient risk limits or changing the operating characteristics of the parent design? Findings This decision analytical model found that the modified study designs were associated with reduced expected study durations. The modified designs were associated with minimal changes in the number of patients treated and the determination of the maximum tolerated dose, without changing the operating characteristics or exceeding the risk limits of the parent design. Meaning Per this analysis, a substantial reduction in the time required to bring new advances to the clinic can be accomplished by simple modifications of 2 commonly used phase 1 trial designs., This decision analytical model assesses a queuing approach to modify the design of phase 1 oncology trials., Importance Phase 1 cancer studies, which guide dose selection for subsequent studies, are almost 3 times more prevalent than phase 3 studies and have a median study duration considerably longer than 2 years, which constitutes a major component of drug development time. Objective To discern a method to reduce the duration of phase 1 studies in adult and pediatric cancer studies without violating risk limits by better accommodating the accrual and evaluation process (or queue). Design The process modeled, the phase 1 queue (IQ), includes patient interarrival time, screening, and dose-limiting toxicity evaluation. For this proof of principle, the rules of the 3 + 3 and rolling 6 phase 1 designs were modified to improve patient flow through the queue without exceeding the maximum risk permitted in the parent designs. The resulting designs, the IQ 3 + 3 and the IQ rolling 6, were each compared with their parent design by simulations in 12 different scenarios. Main Outcomes and Measures (1) The time from study opening to determination of the maximum tolerated dose (MTD), (2) the number of patients treated to determine the MTD, and (3) the association of the design with the dose selected as the MTD. Results Based on 800 simulations, for all 12 scenarios considered, the IQ 3 + 3 and the IQ rolling 6 designs were associated with reduced expected study durations compared with the parent design. The expected IQ 3 + 3 reduction ranged from 1.6 to 10.4 months (with 3.7 months for the standard scenario), and the expected reduction associated with IQ rolling 6 ranged from 0.4 to 10.5 months (with 3.4 months for the standard scenario). The increase in the mean number of patients treated in the IQ 3 + 3 compared with the 3 + 3 ranged from 0.6 to 3.2 patients. No increase in the number of patients was associated with the IQ rolling 6 compared with the rolling 6 design. The probability of selecting a dose level as the MTD changed by less than 3% for all dose levels and scenarios in both parent designs. Conclusions and Relevance This study found that IQ designs were associated with reduced mean duration of phase 1 studies compared with their parent designs without changing the risk limits or MTD selection operating characteristics. These approaches have been successfully implemented in both hematology and solid tumor phase 1 studies.

Immunotherapy has revolutionized cancer therapy. Two of the most recently FDA-approved immunotherapies for B-cell malignancies target CD19, in the form of a Bispecific T-Cell Engager (BiTE) antibody construct or CAR-T cells. Blinatumomab, and FDA-approved BiTE, binds to CD19 on B cells and to CD3 on T cells, mediating killer-target cell contact and T cell activation that results in effective elimination of B cells. Although CD19 is expressed by essentially all cases of B cell malignancies at clinical presentation, relapses with loss or reduction of CD19 surface expression are increasingly recognized as a cause of treatment failure. We have developed a novel BiTE consisting of humanized anti-CD22 and anti-CD3 single chain variable fragments, expressed as a single molecule and purified from tissue culture supernatant. Binding of the anti-CD22 and anti-CD3 moieties to B and T cells, respectively, was confirmed by flow cytometry. CD22-BiTE promoted cell-mediated cytotoxicity in a dose and E:T-dependent fashion, with a maximum NHL and ALL-specific killing activity of 90% in vitro. Besides canonical expression in B cells, CD22 has been reported in non-hematologic malignancies. Our analysis of TCGA data suggests CD22 is expressed in a variety of solid tumors, including sarcoma. We verified expression of CD22 message and protein in solid tumor cell lines. Accordingly, our CD22-BiTE mediated killing of HT1080 sarcoma cells in vitro. In conclusion, we report here the development of a new BiTE with killing activity against CD22+ malignancies which could represent a therapeutic option for B-cell malignancies and potentially solid tumors.

Non-Hodgkin lymphoma (NHL) affects over 400,000 people in the United States; its incidence increases with age. Treatment options are numerous and expanding, yet efficacy is often limited by toxicity, particularly in the elderly. Nearly 70% patients eventually die of the disease. Many patients explore less toxic alternative therapeutics proposed to boost anti-tumor immunity, despite a paucity of rigorous scientific data. Here we evaluate the lymphomacidal and immunomodulatory activities of a protein fraction isolated from fermented wheat germ. Fermented wheat germ extract was produced by fermenting wheat germ with Saccharomyces cerevisiae. A protein fraction was tested for lymphomacidal activity in vitro using NHL cell lines and in vivo using mouse xenografts. Mechanisms of action were explored in vitro by evaluating apoptosis and cell cycle and in vivo by immunophenotyping and measurement of NK cell activity. Potent lymphomacidal activity was observed in a panel of NHL cell lines and mice bearing NHL xenografts. This activity was not dependent on wheat germ agglutinin or benzoquinones. Fermented wheat germ proteins induced apoptosis in NHL cells, and augmented immune effector mechanisms, as measured by NK cell killing activity, degranulation and production of IFNγ. Fermented wheat germ extract can be easily produced and is efficacious in a human lymphoma xenograft model. The protein fraction is quantifiable and more potent, shows direct pro-apoptotic properties, and enhances immune-mediated tumor eradication. The results presented herein support the novel concept that proteins in fermented wheat germ have direct pro-apoptotic activity on lymphoma cells and augment host immune effector mechanisms.