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Background: The interleukin-1 receptor accessory protein (IL1RAP) is highly expressed on acute myeloid leukemia (AML) bulk blasts and leukemic stem cells (LSCs), but not on normal hematopoietic stem cells (HSCs), providing an opportunity to target and eliminate the disease, while sparing normal hematopoiesis. Herein, we report the activity of BIF002, a novel anti-IL1RAP/CD3 T cell engager (TCE) in AML. Methods: Antibodies to IL1RAP were isolated from CD138+ B cells collected from the immunized mice by optoelectric positioning and single cell sequencing. Individual mouse monoclonal antibodies (mAbs) were produced and characterized, from which we generated BIF002, an anti-human IL1RAP/CD3 TCE using Fab arm exchange. Mutations in human IgG1 Fc were introduced to reduce FcγR binding. The antileukemic activity of BIF002 was characterized in vitro and in vivo using multiple cell lines and patient derived AML samples. Results: IL1RAP was found to be highly expressed on most human AML cell lines and primary blasts, including CD34+ LSC-enriched subpopulation from patients with both de novo and relapsed/refractory (R/R) leukemia, but not on normal HSCs. In co-culture of T cells from healthy donors and IL1RAPhigh AML cell lines and primary blasts, BIF002 induced dose- and effector-to-target (E:T) ratio-dependent T cell activation and leukemic cell lysis at subnanomolar concentrations. BIF002 administered intravenously along with human T cells led to depletion of leukemic cells, and significantly prolonged survival of IL1RAPhigh MOLM13 or AML patient-derived xenografts with no off-target side effects, compared to controls. Of note, BiF002 effectively redirects T cells to eliminate LSCs, as evidenced by the absence of disease initiation in secondary recipients of bone marrow (BM) from BIF002+T cells-treated donors (median survival not reached; all survived > 200 days) compared with recipients of BM from vehicle- (median survival: 26 days; p = 0.0004) or isotype control antibody+T cells-treated donors (26 days; p = 0.0002). Conclusions: The novel anti-IL1RAP/CD3 TCE, BIF002, eradicates LSCs and significantly prolongs survival of AML xenografts, representing a promising, novel treatment for AML. [ABSTRACT FROM AUTHOR]

Background Continuing antifungal prophylaxis (AFPx) to prevent invasive mold infections (IMIs) in recipients of allogeneic hematopoietic cell transplantation (alloHCT) after primary hospital discharge from alloHCT admission varies among transplant centers despite recommendations to continue prophylaxis through day +75. Characteristics driving AFPx prescribing at hospital discharge and outcomes are unknown. Methods In this retrospective analysis, we reviewed patients continuing AFPx vs no AFPx at hospital discharge. We included patients with a hospital stay ≥7 days and ≤40 days. We excluded patients with a history of IMI prior to alloHCT, new IMI during admission, or death prior to discharge. Our primary objective was incidence of probable or proven IMI per the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium. Our secondary objectives were nonrelapse mortality at day +100, overall survival at day +100, and characteristics driving AFPx discontinuation at hospital discharge. Results Of the 430 patients identified, 387 met inclusion criteria. At discharge, 56% (217/387) continued AFPx, and 44% (170/387) had no AFPx. At day +100, 3 probable IMI cases occurred in the group with continued AFPx vs 1 probable IMI case in the no-AFPx group (no proven IMI). Univariate analysis showed no difference in cumulative incidence of probable IMI (P =.440), nonrelapse mortality (P =.072), and overall survival (P =.855) between groups. Multivariable logistic regression demonstrated that patients were less likely to continue AFPx if they had a diagnosis other than acute myeloid leukemia, a length of stay ≤30 days, acute graft-vs-host disease grade 0 or 1, and corticosteroid use ≤5 days. Conclusions There was no difference in probable IMI at day +100 after alloHCT based on continuing vs discontinuing AFPx at hospital discharge after alloHCT admission supporting a risk-adapted prophylaxis approach. [ABSTRACT FROM AUTHOR]

Background: Autologous peripheral blood stem cell transplantation (aPBSCT) is the standard of care for adults with relapsed lymphoma, yet recipients remain at risk of developing chronic health conditions (CHCs). It was hypothesized that body composition measurements of skeletal muscle and fat are associated with late‐onset CHCs and nonrelapse mortality after aPBSCT. Methods: Leveraging the Blood or Marrow Transplant Survivor Study, we examined association between pre‐aPBSCT body composition and new‐onset grade 3–5 CHCs among 187 adults with lymphoma treated with aPBSCT (2011–2014) surviving ≥2 years after aPBSCT. Using computed tomography scans at the L3 level, skeletal muscle mass (skeletal muscle area and skeletal muscle density [SMD]) and body fat (subcutaneous adipose tissue and visceral adipose tissue) were measured and quantified as sex‐specific z‐scores. Competing risk models were built to study the impact of body composition on incident grade 3 through 5 CHCs and nonrelapse mortality (NRM) adjusting for confounders. Results: The study cohort had a median age at aPBSCT of 57 years with 63% males, 77% non‐Hispanic Whites and 81% with non‐Hodgkin lymphoma. The 5‐year cumulative incidence of grade 3 through 5 CHCs was 47% (95% Confidence Interval, CI, 38%–56%). Each SD increase in SMD was associated with 30% reduced risk of grade 3 through 5 CHCs (95% CI, 0.50–0.96). The 10‐year cumulative incidence of NRM was 16% (95% CI, 10–22). No body composition measure was associated with NRM. Conclusions: The association between SMD and grade 3 through 5 CHCs following aPBSCT could inform development of prognostic models to identify adults with lymphoma at greatest risk of morbidity following aPBSCT. [ABSTRACT FROM AUTHOR]

This article examines the use of tyrosine kinase inhibitor (TKI) therapy as a maintenance treatment after chimeric antigen receptor (CAR) T-cell therapy in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) who cannot undergo allogeneic hematopoietic cell transplantation (alloHCT). The study presents a case series of seven patients who received CAR-T cells for relapsed/refractory Ph+ ALL and subsequently received TKI maintenance. The article discusses the patients' characteristics and outcomes, emphasizing the need for further research and data on this approach. The study suggests that TKI maintenance therapy after CAR-T may be beneficial, particularly in patients who achieve complete molecular remission (CMR) and have no evidence of minimal residual disease (MRD). The authors recommend larger prospective trials to confirm the effectiveness and safety of TKI maintenance therapy post-CAR-T, and to explore its potential application to other subtypes of ALL. [Extracted from the article]

Standard-of-care treatment for Glioblastoma Multiforme (GBM) is comprised of surgery and adjuvant chemoradiation. Chimeric Antigen Receptor (CAR) T cell therapy has demonstrated disease-modifying activity in GBM and holds great promise. Radiation, a standard-of-care treatment for GBM, has well-known immunomodulatory properties and may overcome the immunosuppressive tumor microenvironment (TME); however, radiation dose optimization and integration with CAR T cell therapy is not well defined. Murine immunocompetent models of GBM were treated with titrated doses of stereotactic radiosurgery (SRS) of 5, 10, and 20 Gray (Gy), and the TME was analyzed using Nanostring. A conditioning dose of 10 Gy was determined based on tumor growth kinetics and gene expression changes in the TME. We demonstrate that a conditioning dose of 10 Gy activates innate and adaptive immune cells in the TME. Mice treated with 10 Gy in combination with mCAR T cells demonstrated enhanced antitumor activity and superior memory responses to rechallenge with IL13Rα2-positive tumors. Furthermore, 10 Gy plus mCAR T cells also protected against IL13Rα2-negative tumors through a mechanism that was, in part, c-GAS-STING pathway-dependent. Together, these findings support combination conditioning with low-dose 10 Gy radiation in combination with mCAR T cells as a therapeutic strategy for GBM. [ABSTRACT FROM AUTHOR]

Background: Blood or marrow transplantation (BMT) survivors carry a high burden of morbidity, yet health care utilization by this vulnerable population remains understudied. Patterns and predictors of various domains of health care utilization in long‐term BMT survivors were evaluated. Methods: Study participants were drawn from the Bone Marrow Transplant Survivor Study (BMTSS). Patients transplanted between 1974 and 2014 at one of three transplant centers who had survived ≥2 years after BMT and were aged ≥18 years at the time of the study were included. A BMTSS survey served as the source of data for health care utilization, sociodemographics, and chronic health conditions. Domains of health care utilization in the 2 years preceding study participation included routine checkups, BMT‐related visits, transplant/cancer center visits, emergency room (ER) visits, hospitalizations, and high health care utilization (≥7 physician visits during the 2 years before the study). Clinical characteristics and therapeutic exposures were abstracted from medical records. Results: In this cohort of 3342 BMT survivors (52% allogeneic), the prevalence of health care utilization declined over time since BMT for both allogeneic and autologous BMT survivors, such that among those who had survived ≥20 years, only 49%–53% had undergone routine checkups, 37%–38% reported BMT‐related visits, and 28%–29% reported transplant/cancer center visits. The presence of severe/life‐threatening conditions and chronic graft‐vs‐host disease increased the odds of health care utilization across all domains. Lower education, lack of insurance, and Hispanic ethnicity were associated with a lower prevalence of routine checkups and/or transplant/cancer center visits. Lower income increased the odds of ER visits but reduced the odds of hospitalizations or high health care utilization. Conclusions: This study identified vulnerable populations of long‐term BMT survivors who would benefit from specialized risk‐based anticipatory care to reduce high health care utilization, ER visits, and hospitalizations. Health care utilization (including routine medical checkups) declines with increasing time since blood or marrow transplantation, except among survivors with severe/life‐threatening chronic health conditions as well as those with chronic graft‐vs‐host disease. Lower education and lack of insurance are associated with lower health care utilization. [ABSTRACT FROM AUTHOR]

AbstractReactive pleocytosis in the CSF has been observed with blinatumomab but has not been well-described. We performed a retrospective study of 88 patients who received intrathecal chemotherapy (IT) while on blinatumomab with CSF analyzed to determine if pleocytosis had an impact efficacy and safety. Blinatumomab was used for relapsed/refractory 62.5%, MRD-positive 31.8%, and consolidation in MRD-negative 5.7%. The incidence of pleocytosis in CSF was 51% and was more frequent after day 15 (55.8% vs. 18.2%, p = 0.025). Pleocytosis did not impact CR, clearance of MRD positivity, PFS and OS rates. Lower incidence of non-CNS extramedullary relapse was seen (3.7% vs. 30.8%, p = 0.011) with pleocytosis in CSF. Analysis of CSF by flow cytometry showed median CD4:CD8 ratio of 1.34. In conclusion, CSF pleocytosis is prevalent with blinatumomab but only demonstrated lower rates of non-CNS extramedullary relapse but no impact on CNS relapse or neurotoxicity. [ABSTRACT FROM AUTHOR]

Immune checkpoint blockade has emerged as a potent new tool in the war on cancer. However, only a subset of cancer patients benefit from this therapeutic modality, sparking a search for combination therapies to increase the fraction of responding patients. We argue here that inhibition of protein phosphatase 2A (PP2A) is a promising approach to increase responses to immune checkpoint blockade and other therapies that rely on the presence of tumor‐reactive T cells. Inhibition of PP2A increases neoantigen expression on tumor cells, activates the cGAS/STING pathway, suppresses regulatory T cells, and increases cytotoxic T cell activation. In preclinical models, inhibition of PP2A synergizes with immune checkpoint blockade and emerging evidence indicates that patients who have tumors with mutations in PP2A respond better to immune checkpoint blockade. Therefore, inhibition of PP2A activity may be an effective way to sensitize cancer cells to immune checkpoint blockade and cell‐based therapies using tumor‐reactive T cells. [ABSTRACT FROM AUTHOR]