Abstract: Cytokine storm due to COVID-19 can cause high morbidity and mortality and may be more common in patients with cancer treated with immunotherapy (IO) due to immune system activation. Objective To determine the association of baseline immunosuppression and/or IO-based therapies with COVID-19 severity and cytokine storm in patients with cancer. Design, Setting, and Participants This registry-based retrospective cohort study included 12 046 patients reported to the COVID-19 and Cancer Consortium (CCC19) registry from March 2020 to May 2022. The CCC19 registry is a centralized international multi-institutional registry of patients with COVID-19 with a current or past diagnosis of cancer. Records analyzed included patients with active or previous cancer who had a laboratory-confirmed infection with SARS-CoV-2 by polymerase chain reaction and/or serologic findings. Exposures Immunosuppression due to therapy; systemic anticancer therapy (IO or non-IO). Main Outcomes and Measures The primary outcome was a 5-level ordinal scale of COVID-19 severity: no complications; hospitalized without requiring oxygen; hospitalized and required oxygen; intensive care unit admission and/or mechanical ventilation; death. The secondary outcome was the occurrence of cytokine storm. Results The median age of the entire cohort was 65 years (interquartile range [IQR], 54-74) years and 6359 patients were female (52.8%) and 6598 (54.8%) were non-Hispanic White. A total of 599 (5.0%) patients received IO, whereas 4327 (35.9%) received non-IO systemic anticancer therapies, and 7120 (59.1%) did not receive any antineoplastic regimen within 3 months prior to COVID-19 diagnosis. Although no difference in COVID-19 severity and cytokine storm was found in the IO group compared with the untreated group in the total cohort (adjusted odds ratio [aOR] , 0.80; 95% CI, 0.56-1.13, and aOR, 0.89; 95% CI, 0.41-1.93, respectively), patients with baseline immunosuppression treated with IO (vs untreated) had worse COVID-19 severity and cytokine storm (aOR, 3.33; 95% CI, 1.38-8.01, and aOR, 4.41; 95% CI, 1.71-11.38, respectively). Patients with immunosuppression receiving non-IO therapies (vs untreated) also had worse COVID-19 severity (aOR, 1.79; 95% CI, 1.36-2.35) and cytokine storm (aOR, 2.32; 95% CI, 1.42-3.79). Conclusions and Relevance This cohort study found that in patients with cancer and COVID-19, administration of systemic anticancer therapies, especially IO, in the context of baseline immunosuppression was associated with severe clinical outcomes and the development of cytokine storm. Trial Registration ClinicalTrials.gov Identifier: NCT04354701

Abstract: Systematic data on the association between anticancer therapies and thromboembolic events (TEEs) in patients with COVID-19 are lacking. Objective To assess the association between anticancer therapy exposure within 3 months prior to COVID-19 and TEEs following COVID-19 diagnosis in patients with cancer. Design, Setting, and Participants This registry-based retrospective cohort study included patients who were hospitalized and had active cancer and laboratory-confirmed SARS-CoV-2 infection. Data were accrued from March 2020 to December 2021 and analyzed from December 2021 to October 2022. Exposure Treatments of interest (TOIs) (endocrine therapy, vascular endothelial growth factor inhibitors/tyrosine kinase inhibitors [VEGFis/TKIs], immunomodulators [IMiDs] , immune checkpoint inhibitors [ICIs], chemotherapy) vs reference (no systemic therapy) in 3 months prior to COVID-19. Main Outcomes and Measures Main outcomes were (1) venous thromboembolism (VTE) and (2) arterial thromboembolism (ATE). Secondary outcome was severity of COVID-19 (rates of intensive care unit admission, mechanical ventilation, 30-day all-cause mortality following TEEs in TOI vs reference group) at 30-day follow-up. Results Of 4988 hospitalized patients with cancer (median [IQR] age, 69 [59-78] years; 2608 [52%] male), 1869 had received 1 or more TOIs. Incidence of VTE was higher in all TOI groups: endocrine therapy, 7%; VEGFis/TKIs, 10%; IMiDs, 8%; ICIs, 12%; and chemotherapy, 10%, compared with patients not receiving systemic therapies (6%). In multivariable log-binomial regression analyses, relative risk of VTE (adjusted risk ratio [aRR] , 1.33; 95% CI, 1.04-1.69) but not ATE (aRR, 0.81; 95% CI, 0.56-1.16) was significantly higher in those exposed to all TOIs pooled together vs those with no exposure. Among individual drugs, ICIs were significantly associated with VTE (aRR, 1.45; 95% CI, 1.01-2.07). Also noted were significant associations between VTE and active and progressing cancer (aRR, 1.43; 95% CI, 1.01-2.03), history of VTE (aRR, 3.10; 95% CI, 2.38-4.04), and high-risk site of cancer (aRR, 1.42; 95% CI, 1.14-1.75). Black patients had a higher risk of TEEs (aRR, 1.24; 95% CI, 1.03-1.50) than White patients. Patients with TEEs had high intensive care unit admission (46%) and mechanical ventilation (31%) rates. Relative risk of death in patients with TEEs was higher in those exposed to TOIs vs not (aRR, 1.12; 95% CI, 0.91-1.38) and was significantly associated with poor performance status (aRR, 1.77; 95% CI, 1.30-2.40) and active/progressing cancer (aRR, 1.55; 95% CI, 1.13-2.13). Conclusions and Relevance In this cohort study, relative risk of developing VTE was high among patients receiving TOIs and varied by the type of therapy, underlying risk factors, and demographics, such as race and ethnicity. These findings highlight the need for close monitoring and perhaps personalized thromboprophylaxis to prevent morbidity and mortality associated with COVID-19–related thromboembolism in patients with cancer.

Abstract: In this multi-institutional retrospective study, we examined characteristics and outcomes of 160 patients with high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS). This rare lymphoma category is defined by high-grade morphologic features, most commonly Burkitt-like, and lack of MYC rearrangements with BCL2 and/or BCL6 rearrangements (so-called double-hit). Our results show that HGBL-NOS tumors are heterogeneous: 83% had a germinal center B-cell immunophenotype, 37% a dual expressor immunophenotype (MYC and BCL2 expression), 28% (single-hit) MYC rearrangement, 13% BCL2 rearrangement, and 11% BCL6 rearrangement. Most patients presented with stage 4 disease, a high serum lactate dehydrogenase, and other high-risk clinical factors. Most frequent first-line regimens included DA-EPOCH-R (43%), R-CHOP (33%), or other intensive chemotherapy programs (11%). We found no significant differences in the rates of complete response (CR, P=0.32), progression-free (PFS, P=0.82), or overall survival (OS, P=0.60) between these chemotherapy regimens. CR was attained by 69% of patients. PFS at 2 years was 55.2% (95%CI, 46.9-62.7), and OS was 68.1% (95%CI, 59.7-75.0). In a multivariable model, the main prognostic factors for PFS and OS were poor performance status, lactate dehydrogenase & gt;3x upper limit of normal, and a dual expressor immunophenotype. Age & gt;60 years or presence of MYC rearrangement were not prognostic, but patients with TP53 alterations had a dismal PFS (13% at 2 years). Presence of MYC rearrangement was not predictive of better PFS in patients treated with DA-EPOCH-R versus R-CHOP. Improvements in the diagnostic criteria and therapeutic approaches beyond dose-intense chemotherapy are needed to overcome the unfavorable prognosis of patients with HGBL-NOS.

Abstract: Patients with double-hit lymphoma (DHL) rarely achieve long-term survival following disease relapse. Some patients with DHL undergo consolidative autologous stem-cell transplantation (autoSCT) to reduce the risk of relapse, although the benefit of this treatment strategy is unclear. Methods Patients with DHL who achieved first complete remission following completion of front-line therapy with either rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or intensive front-line therapy, and deemed fit for autoSCT, were included. A landmark analysis was performed, with time zero defined as 3 months after completion of front-line therapy. Patients who experienced relapse before or who were not followed until that time were excluded. Results Relapse-free survival (RFS) and overall survival (OS) rates at 3 years were 80% and 87%, respectively, for all patients (n = 159). Three-year RFS and OS rates did not differ significantly for autoSCT (n = 62) versus non-autoSCT patients (n = 97), but 3-year RFS was inferior in patients who received R-CHOP compared with intensive therapy (56% v 88%; P = .002). Three-year RFS and OS did not differ significantly for patients in the R-CHOP or intensive therapy cohorts when analyzed by receipt of autoSCT. The median OS following relapse was 8.6 months. Conclusion In the largest reported series, to our knowledge, of patients with DHL to achieve first complete remission, consolidative autoSCT was not associated with improved 3-year RFS or OS. In addition, patients treated with R-CHOP experienced inferior 3-year RFS compared with those who received intensive front-line therapy. When considered in conjunction with reports of patients with newly diagnosed DHL, which demonstrate lower rates of disease response to R-CHOP compared with intensive front-line therapy, our findings further support the use of intensive front-line therapy for this patient population.

Abstract: Background: Early reports suggested that cancer patients have a 1.7-fold increased risk of contracting SARS-CoV-2 and higher rates of severe events and mortality compared with general population. Patients with hematologic malignancies may have worse COVID-19 outcomes, due to an impaired humoral immune response from their underlying malignancy and concurrent anticancer therapy. In this multi-center, retrospective, observational study, we evaluate the associations of COVID-19 outcomes with patient and lymphoma disease characteristics. Methods: EMRs at 10 study centers across the USA identified 519 patients with a diagnosis of lymphoma, CLL, or other lymphoid malignancies, who had a documented positive result of SARS-CoV-2 PCR or nucleocapsid antibody testing. Descriptive statistics were used to summarize the demographic and clinical characteristics. Logistic regression was used to evaluate the associations of individual characteristics with COVID-19 outcomes, adjusted for center (NYU vs. other). The interactions between each of the variables was also included in these models; since the interactions were generally small and non-significant, only the main effect of center was included. Two-sided p-values ≤0.05 were considered significant; there were no adjustments for multiple variables or endpoints. Each analysis was based on complete data for that analysis. Results: Tables 1 and 2 provide demographic and clinical characteristics, respectively, of the 519 patients. The mean age was 61.9 years, with 296 (57%) male and 374 (72%) white patients. NYU had the largest cohort (318 patients), with the remaining centers contributing a range of 3 to 69 patients (median 14). Logistic regression models for the association of each COVID-19 outcome with individual clinical and patient characteristics included adjustments for the center (NYU/other). While center effects were statistically significant, center by covariate interaction effects were not and are not included in the final models. The odds ratio (OR) estimates and p-values for each patient and CLL/lymphoma clinical variable are shown in Tables 3 and 4, respectively. The risks of experiencing a severe event, death, and hospital admission increased with age; for each 10 years of age increase, the ORs were 1.58 for experiencing severe events, 1.78 for death, and 1.65 for hospital admission. The risks of poor outcome were higher in males than in females (OR 1.93 for severe events, 1.85 for death, and 1.47 for hospital admission). Patients with Charlson Comorbidity Index (CCI) & gt;5 had a higher risk of severe events (OR 2.46), mortality (3.30) and hospital admission (2.73) compared to patients with CCI ≤5. Compared to patients with HL, patients with aggressive NHL had a higher risk of severe events (OR 4.05), mortality (4.68) and hospital admission (4.65). Patients with CLL similarly had a higher risk of severe events (OR 4.64), mortality (4.65) and hospital admission (5.93) compared to HL patients. Patients with indolent NHL had a higher risk of hospital admission (OR 3.95) but not a higher risk of mortality compared to HL. Patients in remission at the time of COVID-19 diagnosis had a lower risk of severe events (OR 0.42), mortality (0.36) and hospital admission (0.40) relative to those who were not in remission. Patients who received cytotoxic chemotherapy within 28 days of their COVID-19 diagnosis had a higher risk of severe events (OR 2.54), mortality (2.79), and hospital admission (2.31). Patients who received an anti-CD20 monoclonal antibody within 6 months of COVID-19 diagnosis had a higher risk of severe events (OR 2.60), mortality (2.17) and hospital admission (3.28). Conclusions: In addition to demographic and comorbidity risk factors identified in previous studies, our study shows that patients with aggressive NHL and CLL, or patients who have received recent cytotoxic chemotherapy or anti-CD20 mAB, may be at risk for poor COVID-19 outcome. The difference in risk between NHL and HL patients is likely associated with young age of HL patients but may also be related to differences in underlying innate and adaptive immune defects. Patients at high risk for poor outcome should be a priority for studies of monoclonal antibody prophylaxis. If defects in humoral immunity are at the root of poor outcome, this may be compounded by poor response to vaccination. Multivariate analysis of this data will be completed in advance of the meeting. Figure 1 Figure 1. Disclosures Olszewski: Celldex Therapeutics: Research Funding; PrecisionBio: Research Funding; TG Therapeutics: Research Funding; Acrotech Pharma: Research Funding; Genentech, Inc.: Research Funding; Genmab: Research Funding. Barta: Daiichi Sankyo: Honoraria; Seagen: Honoraria; Acrotech: Honoraria; Kyowa Kirin: Honoraria. Hernandez-Ilizaliturri: AbbVie: Other: Advisory Boards; Incyte: Other: Advisory Boards; Celgene: Other: Advisory Boards; BMS: Other: Advisory Boards; Pharmacyclics: Other: Advisory Boards; Amgen: Other: Advisory Boards; Kite: Other: Advisory Boards; Gilead: Other: Advisory Boards; Epyzime: Other: Advisory Boards. Leslie: Janssen: Consultancy, Speakers Bureau; Merck: Consultancy; Abbvie: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria, Speakers Bureau; PCYC/Janssen: Consultancy, Honoraria, Speakers Bureau; Seagen: Consultancy, Honoraria, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; Celgene/BMS: Consultancy, Honoraria, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy; BeiGene: Consultancy, Honoraria, Speakers Bureau; Karyopharm Therapeutics: Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Pharmacyclics: Consultancy, Honoraria, Speakers Bureau. Diefenbach: Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Merck Sharp & Dohme: Consultancy, Honoraria, Research Funding; Morphosys: Consultancy, Honoraria, Research Funding; Genentech, Inc./ F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Perlmutter Cancer Center at NYU Langone Health: Current Employment; Incyte: Research Funding; AbbVie: Research Funding; Trillium: Research Funding; IGM Biosciences: Research Funding; IMab: Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Gilead: Current equity holder in publicly-traded company; MEI: Consultancy, Research Funding; Celgene: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding.

Abstract: 335 Background: While preoperative chemoradiation followed by surgery is the standard approach for patients (pts) with newly diagnosed clinical stage II-III rectal cancer, many are unable to tolerate postoperative adjuvant chemotherapy which may compromise disease-free and overall survival. CONTRE is a multicenter phase II study designed to determine the feasibility of administering all chemotherapy prior to surgery and to assess its impact on pathologic complete response (pCR) and complete (R0) resection Methods: Pts with T3-4 and/or N1-2 rectal cancer, staged by endorectal ultrasound (ERUS) and pelvic MRI, receive modified (m) FOLFOX6 every 2 weeks x 8 cycles, followed by repeat MRI and proctoscopy to assess response. Pts then receive 50.4 Gy IMRT with 5-FU 225 mg/m 2 /day or capecitabine 825mg/m 2 BID, 5 days per week during radiation, followed by surgery 4-8 weeks later. Results: Thus far, we have enrolled 36 of a planned 39 pts (median age 58, range 30-79; T2-1, T3-30, T4-2; N1-20, N2-7). 28 of the first 30 (93%) completed 8 cycles of mFOLFOX6. 26 pts have completed chemoradiation while 2 chose to proceed directly to surgery. All patients opted to receive capecitabine during radiation. Grade 3/4 toxicities during chemotherapy and chemoradiation have included diarrhea (16%) and neutropenia (12%), with grade 3 renal and cardiac toxicities reported in one patient each. A clinical complete response after chemotherapy alone was achieved in 3 of 29 (10%). Of the first 21 pts undergoing surgery, pCR has been achieved in 6 (29%) and R0 resections in 100%. Thus far, all pts have been able to undergo sphincter-sparing resections. Study accrual will be completed by the meeting. Conclusions: A larger proportion of stage II-III rectal cancer pts are able to complete mFOLFOX6 ( 〉 90% in our cohort) when administered prior to chemoradiation and surgery. Complete neoadjuvant treatment may represent a well-tolerated alternative to the current standard treatment sequence and a platform for the evaluation of novel therapeutics such as targeted agents during preoperative therapy. Funded in part by LIFEcycle, Inc. Clinical trial information: NCT01363843.

Abstract: Background: The term HGBL, NOS was introduced by the World Health Organization (WHO) in 2016 for aggressive B-cell lymphomas with Burkitt lymphoma-like (BLL) or blastoid cytomorphology that lack double-hit genetics and do not meet criteria for other entities. Diagnostic patterns and prognosis of these rare tumors are not well understood. We examined the characteristics and outcomes of patients (pts) with HGBL, NOS diagnosed in 17 academic centers across the United States. Methods: We collected retrospective data on HGBL, NOS cases diagnosed by academic hematopathologists in 2017-2021; 8 centers performed a local review by lymphoma pathology experts to confirm fulfillment of the WHO criteria; pathology reports were reviewed centrally. We excluded pts not tested for MYC rearrangement (MYC-R), any double/triple-hit, diffuse large B-cell, or lymphoblastic lymphomas. Immunohistochemistry (IHC) and cytogenetic tests were done locally. Outcomes included rates of complete response (CR), progression-free (PFS) and overall survival (OS) estimated with 95% confidence intervals (CI). Results: Among 126 pts with HGBL, NOS, median age was 64 years (range 18-91), 67% were male, and 3 were HIV+. Advanced stage was present in 68%, poor performance status (PS, ECOG ≥2) in 21%, high serum lactate dehydrogenase (LDH) in 68%, extranodal (EN) sites in 79%, central nervous system (CNS) involvement in 6%, and International Prognostic Index (IPI) ≥ 3 in 55%. Cytomorphology was reported as BLL in 59 (47%) cases, blastoid in 28 (22%), and unspecified in 39 (31%). By IHC, 83% had germinal center B-cell (GCB) phenotype. Using cases with available data, CD10 was expressed in 79%, BCL6 in 81%, MUM1/IRF4 in 48%, MYC in 73%, BCL2 in 55% (dual MYC/BCL2 expressor [DEL]: 37%), CD5 in 13%, and median Ki-67 was 95%. MYC-R (single-hit) was detected in 27% (Fig A), MYC extra copies (EC) in 9%, BCL2-R in 13%, and BCL6-R in 10%. MYC-EC were present in 16% of cases with BCL2-R or BCL6-R, and BCL2/BCL6-EC in 12% of those with MYC-R. Blastoid tumors were more likely than BLL to involve & gt;1 EN site or to have BCL2-R (Fig B). 9 cases were assessed by next generation sequencing and 5 (56%) had a TP53 mutation. Cases which underwent confirmatory pathology review (N=74) did not differ from others clinically but more often had a well-defined HGBL morphology (77% vs 58%, P=.031) and less often MYC-R (20% vs. 37%, P=.004). The most common first-line regimens (among treated pts, N=121) were DA-EPOCH-R (50%) and RCHOP (35%), with few pts receiving HyperCVAD/MA (5%) or CODOX-M±IVAC (2%); 97% received rituximab, and 44% CNS prophylaxis. Pts selected for DA-EPOCH-R vs. RCHOP were younger (median 61 vs. 68 years, P=.006), more often had stage 3/4 (P=.04), BLL morphology (56% vs. 29%, P=.009) or MYC-R (31% vs. 14%, P=.06). CR was attained in 62% of pts, whereas 20% had progressive disease. The most frequent salvage regimens (± rituximab) included ICE (N=12), DHAP (N=6), and GemOx (N=5). 3 pts underwent autologous, and 3 allogeneic transplant (2/3 subsequently relapsed). 13 received chimeric antigen receptor (CAR) T-cells, with response noted in 7 (54%) and CR in 4 (31%); HGBL relapsed in 3/7 (43%) responders. With median follow-up of 2.7 years, 39% of pts relapsed, and 33% died. Of 49 observed relapses, 13 (27%) involved the CNS. PFS estimate at 2 years was 51% (95% CI, 42-60%) and OS was 68% (95% CI, 58-76%; Fig C). PFS and OS were not significantly associated with age or PS, but stage and LDH were prognostic (Fig D-G). Furthermore, PFS did not differ by BLL/blastoid morphology, MYC-R status or DEL status, but non-GCB tumors had somewhat worse PFS (Fig H-J). We observed no significant PFS (or OS) difference between pts selected for RCHOP vs. DA-EPOCH-R (P=.83 for PFS, Fig K; P=.55 for OS) in aggregate or in any subset, except for de novo tumors with BLL morphology (N=41), where DA-EPOCH-R showed a superior 2-year PFS (73% vs 38% for RCHOP, P=.027; stratified by IPI: P=.040, Fig L). Conclusions: HGBL, NOS, as diagnosed in current academic practice, is highly heterogeneous, highlighting the need to classify high-grade lymphomas using molecular rather than morphologic features. Considering poor survival in all age groups (except for few pts with early stage and normal LDH), lack of prognostic significance of MYC-R, DEL status, or cytomorphology, HGBL, NOS needs prospective trials to delineate prognostic biomarkers, the role of intensified chemotherapy, and novel therapeutic approaches. Figure 1 Figure 1. Disclosures Landsburg: Triphase: Research Funding; Takeda: Research Funding; Curis: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: DSMB member; ADCT: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees. Hughes: Acerta Pharma: Research Funding; AstraZeneca: 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; Genzyme: Consultancy; Janssen: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Sandoval-Sus: SeaGen, Janssen, MassiveBio, TG: Other: Advisory Board; BMS: Other: Advisory Board, Speakers Bureau. Kothari: Incyte pharmaceuticals: Consultancy, Honoraria; Karyopharm pharmaceuticals: Consultancy, Honoraria. Torka: TG Therapeutics: Membership on an entity's Board of Directors or advisory committees. Smith: Acerta Pharma BV: Research Funding; ADC Therapeutics: Consultancy; AstraZeneca: Consultancy, Research Funding; De Novo Biopharma: Research Funding; Ignyta (spouse): Research Funding; Beigene: Consultancy, Research Funding; Portola Pharmaceuticals: Research Funding; Incyte: Consultancy; Incyte Corporation: Research Funding; Karyopharm: Consultancy; KITE pharm: Consultancy; Merck Sharp & Dohme Corp: Research Funding; Ayala (spouse): Research Funding; Bayer: Research Funding; Genentech: Research Funding; Bristol Myers Squibb (spouse): Research Funding; Millenium/Takeda: Consultancy. Epperla: Genzyme: Honoraria; Karyopharm: Other: Ad Board; Beigene: Speakers Bureau; Verastem: Speakers Bureau. Bond: Kite/Gilead: Honoraria. Naik: Sanofi: Other: Virtual Advisory Board Member ; Takeda: Other: Virtual Advisory Board Member ; Kite: Other: Virtual Advisory Board Member. Kamdar: ADC Therapeutics: Consultancy; AbbVie: Consultancy; KaryoPharm: Consultancy; Kite: Consultancy; Adaptive Biotechnologies: Consultancy; AstraZeneca: Consultancy; Celgene (BMS): Consultancy; TG Therapeutics: Research Funding; Genentech: Research Funding; Genetech: Other; Celgene: Other; SeaGen: Speakers Bureau. Haverkos: Viracta Therapeutics: Consultancy. Karmali: BMS/Celgene/Juno: Consultancy, Research Funding; Takeda: Research Funding; Roche: Consultancy; Epizyme: Consultancy; Janssen/Pharmacyclics: Consultancy; EUSA: Consultancy; Genentech: Consultancy; Karyopharm: Consultancy; AstraZeneca: Speakers Bureau; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; Morphosys: Consultancy, Speakers Bureau; BeiGene: Consultancy, Speakers Bureau. Vose: Kite, a Gilead Company: Honoraria, Research Funding. Olszewski: PrecisionBio: Research Funding; Celldex Therapeutics: Research Funding; TG Therapeutics: Research Funding; Acrotech Pharma: Research Funding; Genentech, Inc.: Research Funding; Genmab: Research Funding.

Abstract: Background: Allogeneic stem cell transplant (allo-SCT) is a cornerstone in the treatment of Acute Myeloid Leukemia (AML) exerting much of its therapeutic efficacy through the graft-versus-leukemia effect. The administration of immunoregulatory cells via engrafted donor lymphocytes is essential to the eradication of residual malignancy and long-term survival. Many patients, however, either do not have an allo-SCT donor or cannot withstand the toxicity of allo-SCT. Previous studies have shown durable responses in AML patients following donor lymphocyte infusions in the absence of engraftment in both the frontline and relapsed setting (Dey et al, BJH 2005, Colvin et al, BBMT 2009, Ai et al, Blood 2010). In this clinical trial we propose a role for donor leukocyte infusions (DLI) in the absence of engraftment. Without the need for engraftment patients will not need to receive high dose chemotherapy or radiation and the toxicities that accompany these therapies. Instead, allogeneic donor cells are infused into patient with relapsed/refractory (R/R) AML to serve as a potent immune stimulator. Prior to DLI, patients will receive fractionated dosing of gemtuzumab ozogamicin (GO). GO is an anti-CD-33 antibody drug conjugate approved in combination with induction therapy for de novo AML and in R/R disease. Patients who demonstrate a CR or CRi to therapy will go on to have up to 2 additional GO + DLI treatments. Bone marrow and blood samples will be obtained from patients before, during, and after treatment to determine immune effector cells (both donor and patient), cytokine release profiles, and extracellular vesicle components. Study Design and Methods: Our study, BrUOG 345 [NCT03374332], evaluates the combination of fractionated GO with non-engraftment DLI in the treatment of patients with R/R AML. Adults patients 18 years of age and older with histologically confirmed R/R AML who have had recurrence or progression after at least 1 prior standard treatment are eligible. Enrollees must have no active systemic infections and have adequate lung, liver, cardiac, and renal function with an ECOG PS 0-1. Fractionated GO 6-9mg/m2 will be administered on days 1, 4, and 7 followed by infusion of 1-2x108 CD3 cells/kg from a 0-3/6 HLA mismatched related donor cell. Patients that are in CR or CRi can receive up to 2 additional treatments with GO+DLI (Figure 1). The primary objective of the phase 1 portion is to determine the maximum tolerated dose (MTD) of DLI in combination with GO while the primary objective of Phase 2 portion is to assess the response rate after one cycle of fractionated GO followed by non-engraftment DLI in patients with relapsed/refractory AML. The study will initially utilize a 3+3 design in Phase 1 to determine if 1-2x108 CD3 cells/kg can be safely administered with GO. This study will target a response rate of 57% considered to be interesting enough to warrant further study in a randomized setting. With this hypothesis in mind, the phase 2 portion of the study will use Simon's two-stage design. The null hypothesis that the true response rate (CR and CRi) is only 29% will be tested against a one-sided alternative. In the first stage, 9 subjects will be accrued. Patients treated at MTD in the Phase 1 portion of the study will be included in this cohort. If there are 3 or fewer responses in these 9 patients, the study will be stopped for futility. Otherwise, 6 additional subjects will be accrued for a total of 15. The null hypothesis will be rejected if 7 or more responses are observed in 15 patients. This design yields a type I error rate of 0.1 and power of 80% if the true response rate is 57%. A continuous assessment of toxicity will be utilized for the Phase 2 portion of this study. Sequential boundaries will be used to monitor dose-limiting toxicity rate for patients after the initial MTD is determined. Accrual will be halted if excessive numbers of dose-limiting toxicities are seen. The primary outcome of the Phase 2 portion is the CR/CRi rate following GO and non-engraftment DLI. Secondary outcomes will include survival, both progression-free (PFS) and overall (OS) until two years post treatment, and dose limiting toxicities until 16 weeks post-infusion. Additional lab correlative studies will be performed including CD33 expression before, during, and after GO infusion and T-cell activation markers, antigen presenting cell/macrophage amounts, cytokine release profiles, and extracellular vesicle measurements (Figure 1). Disclosures Olszewski: TG Therapeutics: Research Funding; Spectrum Pharmaceuticals: Research Funding; Adaptive Biotechnologies: Research Funding; Genentech: Research Funding. Reagan:Pfizer: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees.

Abstract: Hematologic malignancies and their treatments impaired humoral immunity from coronavirus disease 2019 vaccination, and booster vaccine overcame a lack of initial response in 58% of patients, including 63% those on active therapy. The findings indicated that booster vaccinations should be strongly encouraged; however, even with boosters, many remain unprotected, which should inform infection prevention and treatment strategies.