A Platform to Deliver Single and Bi-specific Cas9/guide RNA to Perturb Genes in Vitro and in Vivo.

Although CRISPR/Cas9 technology is poised to revolutionize the treatment of diseases with underlying genetic mutations, it faces some significant issues limiting clinical entry. They include low-efficiency in vivo systemic delivery and undesired off-target effects. Here, we demonstrate, by modifying Cas9 with phosphorothioate DNA oligos (PS), one can efficiently deliver single and bi-specific CRISPR/Cas9/guide RNA (gRNA) dimers in vitro and in vivo with reduced off-target effects. We show that PS-Cas9/gRNA-mediated gene knockout preserves chimeric antigen receptor T cell viability and expansion in vitro and in vivo. PS-Cas9/gRNA mediates gene perturbation in patient-derived tumor organoids and mouse xenograft tumors, leading to potent tumor antitumor effects. Further, HER2 antibody-PS-Cas9/gRNA conjugate selectively perturbs targeted genes in HER2+ ovarian cancer xenografts in vivo. Moreover, we created bi-specific PS-Cas9 with two gRNAs to target two adjacent sequences of the same gene, leading to efficient targeted gene disruption ex vivo and in vivo with markedly reduced unintended gene perturbation. Thus, the cell-penetrating PS-Cas9/gRNA can achieve efficient systemic delivery and precision in gene disruption.

Sex-based Differences in Risk for Therapy-related Myeloid Neoplasms.

BACKGROUND: Therapy-related myeloid neoplasm (t-MN) is a life-threatening complication of autologous peripheral blood stem cell (PBSC) transplantation for non-Hodgkin lymphoma (NHL). Prior studies report an association between clonal hematopoiesis (CH) in PBSC and risk of t-MN, but small samples precluded examination of risk within specific sub-populations. METHODS: Targeted DNA sequencing was performed to identify CH mutations in PBSC from a retrospective cohort of 984 NHL patients (median age at transplant 57y; range: 18-78). Fine-Gray proportional subdistribution hazard regression models estimated association between number of CH mutations and t-MN, adjusting for demographic, clinical, and therapeutic variables. Secondary analyses evaluated association between CH and t-MN among males and females. RESULTS: CH was identified in PBSC from 366 patients (37.2%). t-MN developed in 60 patients after median follow-up of 5y. Presence of ≥2 mutations conferred increased t-MN risk (adjusted hazard ratio [aHR]=2.10, 95% confidence interval [CI]=1.08-4.11, p=0.029). CH was associated with increased t-MN risk among males (aHR=1.83, 95%CI=1.01-3.31) but not females (aHR=0.56, 95%CI=0.15-2.09). Although prevalence and type of CH mutations in PBSC was comparable, the 8y cumulative incidence of t-MN was higher among males vs. females with CH (12.4% vs. 3.6%) but was similar between males and females without CH (4.9% vs. 3.9%). Expansion of CH clones from PBSC to t-MN was seen only among males. CONCLUSIONS: Presence of CH mutations in PBSC confers increased risk of t-MN after autologous transplantation in male but not female patients with NHL. Factors underlying sex-based differences in risk of CH progression to t-MN merit further investigation.

Phase I Trial of Brentuximab Vedotin Plus Cyclosporine in Relapsed/Refractory Hodgkin Lymphoma.

INTRODUCTION: BV is an antibody-drug conjugate directed against CD30 and is safe and effective in relapsed/refractory (R/R) Hodgkin lymphoma (HL). Most patients with r/r cHL respond well to BV monotherapy; however, the large of majority of them eventually progress on this drug, and BV-resistant HL remains an unmet need. Preclinical data suggest that BV resistance is mediated at least in part by increased drug efflux associated with increased expression of multidrug resistance pump 1 (MDR1) while CD30 expression appears to be preserved in BV resistant cell lines and patient samples. We conducted a phase 1 study evaluating BV + cyclosporine (CsA) in BV-refractory HL and previous reported results in the dose finding cohort. Here we report the final results from the phase 1 study. METHODS: This was a phase I trial of BV + CsA in patients with r/r HL with dose-finding and dose escalation cohorts. Eligibility criteria included age ≥ 18 years with r/r HL after at least 1 prior line of therapy. Treatment consisted of 1.8 mg/kg BV intravenously on day 1 and CsA 5 to 7.5 mg/kg PO twice daily on days 1 to 5; cycles were 21 days long. Patients in the expansion cohort had to have cHL refractory to BV. The primary objectives were to evaluate safety and tolerability and to determine MTD of BV + CsA; the secondary objective was to determine efficacy of this combination. RESULTS: 29 patients were enrolled onto the study, 14 in the dose finding cohort and 15 in the dose expansion BV refractory cohort. Study accrual was terminated before target accrual due to unacceptable toxicity. 62% of patients were male, and the median age was 36 years (range: 20-69). The median number of prior therapies was 5 (range: 3-12); all patients had prior BV, and 93% had PD-1 directed therapy, and 93% were BV-refractory. Of 22 evaluable patients, CR rate was 27% and ORR 64%; median DOR 4.9 months. Treatment-related deaths occurred in 3 patients, and another patient died during cycle 1 due to cardiac arrest deemed unlikely related to be protocol therapy. All grade GI toxicity was seen in 90% of patients (G3+ in 24%); other common adverse events were nausea (90%), hypertension (90%), nausea (90%), hypertension (90%), anemia (86%), fatigue (76%), neutropenia (76%), leukopenia (76%), hypomagnesemia (76%), anorexia (66%), and hyponatremia (66%). DISCUSSION: BV + CsA demonstrated modest activity in BV-refractory r/r HL; however, toxicity is substantial.

Evaluation of the Immunomodulatory Effects of Radiation for Chimeric Antigen Receptor T Cell Therapy in Glioblastoma Multiforme.

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.

Brentuximab vedotin plus cyclophosphamide, doxorubicin, etoposide, and prednisone followed by brentuximab vedotin consolidation in CD30-positive peripheral T-cell lymphomas: a multicentre, single-arm, phase 2 study.

BACKGROUND: CD30 expression is universal in anaplastic large-cell lymphoma and is expressed in some other peripheral T-cell lymphoma subtypes. Incorporation of brentuximab vedotin into initial therapy for people with CD30-positive peripheral T-cell lymphomas prolonged progression-free survival, but there is room for improvement, especially for people with non-anaplastic large-cell lymphoma subtypes. METHODS: We conducted a multicentre, international, single-arm, phase 2 trial to evaluate the safety and activity of CHEP-BV (cyclophosphamide, doxorubicin, prednisone, brentuximab vedotin, and etoposide) followed by brentuximab vedotin consolidation in patients with CD30-expressing peripheral T-cell lymphomas across five academic centres in the USA and Canada. Adults aged 18 years or older with newly diagnosed, untreated CD30-positive peripheral T-cell lymphomas, Eastern Cooperative Oncology Group score of 0-2, and adequate organ function were eligible to receive six planned cycles of CHEP-BV (ie, 1·8 mg/kg brentuximab vedotin intravenously on day 1, cyclophosphamide 750 mg/m2 intravenously on day 1, doxorubicin 50 mg/m2 intravenously on day 1, etoposide 100 mg/m2 daily intravenously on days 1-3, and prednisone 100 mg daily orally on days 1-5) with prophylactic G-CSF. Patients who responded to the treatment could receive brentuximab vedotin consolidation for up to ten additional cycles either after autologous haematopoietic stem-cell transplantation (HSCT) or directly after CHEP-BV. The primary endpoints were unacceptable toxicity during a 3-plus-3 safety lead-in in participants who received study treatment and completed the safety evaluation period (to confirm the recommended phase 2 dose of brentuximab vedotin in CHEP-BV) and the complete response rate after CHEP-BV induction therapy in participants who received study treatment and had response evaluation. The study was registered at ClinicalTrials.gov (NCT03113500), and this cohort completed the trial. The trial is ongoing with the enrolment of a new cohort. FINDINGS: 54 patients were screened for eligibility and 48 were eligible for the study. The participants (18 [38%] women and 30 [63%] men; 34 [71%] White, four [8%] Black, five [10%] Asian, ten [21%] Hispanic, and 37 [77%] non-Hispanic people) were recruited and enrolled between Dec 4, 2017, and June 14, 2021, and followed up until Aug 25, 2023, when the database was locked for analysis. 48 participants were evaluable for toxicity, and 47 were evaluable for response (one participant died from COVID-19 before response assessment). During the safety lead-in, one of six participants had an unacceptable toxicity (ie, platelet count <10 000 per mm3 in a participant with extensive bone marrow involvement), and the proposed phase 2 dose of 1·8 mg/kg brentuximab vedotin in CHEP-BV was confirmed. At completion of CHEP-BV, 37 of 47 participants had complete response, yielding a complete response rate of 79% (95% CI 64-89). The most common CHEP-BV-related toxicities of grade 3 or higher were neutropenia (14 [29%] of 48), leukopenia (11 [23%]), anaemia (ten [21%]), febrile neutropenia (ten [21%]), lymphopenia (nine [19%]), and thrombocytopenia (nine [19%]). There were no treatment-related deaths. INTERPRETATION: In patients with mostly CD30-expressing peripheral T-cell lymphomas other than non-anaplastic large-cell lymphoma, CHEP-BV (with or without autologous HSCT) followed by brentuximab vedotin consolidation was safe and active. FUNDING: SeaGen, Leukemia and Lymphoma Society, Lymphoma Research Foundation, and the National Cancer Institute of the National Institutes of Health.

PSCA-CAR T cell therapy in metastatic castration-resistant prostate cancer: a phase 1 trial.

Despite recent therapeutic advances, metastatic castration-resistant prostate cancer (mCRPC) remains lethal. Chimeric antigen receptor (CAR) T cell therapies have demonstrated durable remissions in hematological malignancies. We report results from a phase 1, first-in-human study of prostate stem cell antigen (PSCA)-directed CAR T cells in men with mCRPC. The starting dose level (DL) was 100 million (M) CAR T cells without lymphodepletion (LD), followed by incorporation of LD. The primary end points were safety and dose-limiting toxicities (DLTs). No DLTs were observed at DL1, with a DLT of grade 3 cystitis encountered at DL2, resulting in addition of a new cohort using a reduced LD regimen + 100 M CAR T cells (DL3). No DLTs were observed in DL3. Cytokine release syndrome of grade 1 or 2 occurred in 5 of 14 treated patients. Prostate-specific antigen declines (>30%) occurred in 4 of 14 patients, as well as radiographic improvements. Dynamic changes indicating activation of peripheral blood endogenous and CAR T cell subsets, TCR repertoire diversity and changes in the tumor immune microenvironment were observed in a subset of patients. Limited persistence of CAR T cells was observed beyond 28 days post-infusion. These results support future clinical studies to optimize dosing and combination strategies to improve durable therapeutic outcomes. ClinicalTrials.gov identifier NCT03873805 .

Yttrium-90 Anti-CD25-BEAM-Conditioning for Autologous Hematopoietic Cell Transplantation in Peripheral T Cell Lymphoma.

Peripheral T cell lymphomas (PTCL) have a poor prognosis with current treatments. High-dose chemotherapy followed by autologous hematopoietic cell transplant (AHCT) is used as a consolidation strategy after achieving clinical remission with first-line therapy, as well as in chemosensitive relapse if allogeneic transplant is not an option. CD25 is a targetable protein often highly expressed in PTCL. In this phase 1 clinical trial, we tested the addition of beta-emitting 90Y-labeled chimeric anti-CD25 basiliximab (aTac) to BEAM (carmustine, etoposide, cytarabine, melphalan) as conditioning for AHCT in patients with PTCL. Twenty-three AHCT-eligible patients were enrolled, and 20 received therapeutic 90Y-aTac-BEAM AHCT. Radiation doses of 0.4, 0.5 and 0.6 mCi/kg were tested. With no observed dose-limiting toxicities, 0.6 mCi/kg was deemed the recommended phase 2 dose. The most prevalent adverse effect, grade 2 mucositis, was experienced by 80% of patients. As of this report, 6 (30%) of the treated patients had died, 5 due to progressive disease and 1 due to multiple organ failure [median time of death 17 mo (range: 9-21 mo)] post-AHCT. Median follow-up was 24 mo (range: 9-26 mo) overall and 24 mo (range: 13-26 mo) for surviving patients. For patients who received therapeutic 90Y-aTac-BEAM AHCT, the 2-year progression-free and overall survival were 59% (95% CI: 34-77%) and 68% (95% CI: 42-84%), respectively. 90Y-aTac-BEAM appears to be safe as an AHCT conditioning regimen for PTCL, with no increased toxicity over the toxicities historically seen with BEAM alone in this patient population. This trial was registered at www.clinicaltrials.gov as # NCT02342782.

A combination of protein phosphatase 2A inhibition and checkpoint immunotherapy: a perfect storm.

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.

Clonal Hematopoiesis is Associated With Severe Cytokine Release Syndrome in Patients Treated With Chimeric Antigen Receptor T-Cell (CART) Therapy.

Among patients receiving CD19 or B-cell maturation antigen (BCMA) CAR T therapy, inflammation pre- and post-CAR T infusion is implicated in the development of toxicities including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and likely contributes to prolonged cytopenias. Clonal hematopoiesis (CH), the clonal expansion of hematopoietic stem cells harboring somatic mutations, has been associated with inflammasome upregulation. Herein, we examined the prevalence of pre-CAR T CH in a predominantly transplant-naïve cohort of recipients with non-Hodgkin lymphoma (NHL) or multiple myeloma (MM), and assessed the relationship between the presence of CH mutations and CAR T-related outcomes including CRS, ICANS, prolonged cytopenia, progression-free survival (PFS), and overall survival (OS). This study included 62 patients with NHL or MM who underwent CD19 or BCMA CAR T therapy from 2017 to 2022 at City of Hope and had available pre-CAR T cryopreserved peripheral blood mononuclear cells (PBMCs). DNA was isolated with QIAamp DNA Mini Kit (Qiagen) from PBMC samples (94% collected <30d of CART infusion), on which we performed targeted exome sequencing (108 pre-defined gene panel with 1000x sequencing depth) to determine the presence of CH (variant allele frequency [VAF] ≥2%). Multivariable logistic regression was used to examine the association between CH and absolute neutrophil count (ANC) recovery at day +30 and +60, maximum grade CRS and ICANS, grade <2 versus 2+, and OS and PFS at 1y. Covariates considered were age at CART, baseline ANC, sex, race, CAR-HEMATOTOX, LDH, bridging therapy (Y/N), and number of prior lines of therapy. Fifteen (24%) patients had at least one pathogenic CH mutation; 2 (13%) had ≥2 CH mutations concurrently. DMT3A mutations were the most common; 29% of mutations had VAFs >10%. Patients with CH were significantly more likely to develop grade ≥2 CRS (60% versus 28%, p = .03) compared to those without CH (odds ratio [OR] 3.9, 95% CI 1.2-13.2; p = .027). Accounting for baseline ANC (which was higher among the CH cohort and associated with delayed ANC recovery, p = .02) patients with CH did not have a significantly different rate of delayed ANC recovery compared to those without CH (adjusted OR 0.37, 95% CI 0.09-1.5; p = .17). There was no association between CH and ICANS, nor with 1y PFS or OS. CH was frequent (24%) in this cohort of CAR T recipients and was associated with a higher risk of development of grade ≥2 CRS after CAR T. Additional validation studies are currently underway, which may set the stage for consideration of pre-CAR T CH as a biomarker for risk stratification towards more proactive CRS prophylaxis. Translational studies could aim to prove a direct relationship between CH-mutated myeloid cells and CRS.

Nonsignaling extracellular spacer regulates tumor antigen selectivity of CAR T cells.

Advancing chimeric antigen receptor (CAR)-engineered T cells for the treatment of solid tumors is a major focus in the field of cellular immunotherapy. Several hurdles have hindered similar CAR T cell clinical responses in solid tumors as seen in hematological malignancies. These challenges include on-target off-tumor toxicities, which have inspired efforts to optimize CARs for improved tumor antigen selectivity and overall safety. We recently developed a CAR T cell therapy targeting prostate stem cell antigen (PSCA) for prostate and pancreatic cancers, showing improved preclinical antitumor activity and T cell persistence by optimizing the intracellular co-stimulatory domain. Similar studies were undertaken to optimize HER2-directed CAR T cells with modifications to the intracellular co-stimulatory domain for selective targeting of breast cancer brain metastasis. In the present study, we evaluate various nonsignaling extracellular spacers in these CARs to further improve tumor antigen selectivity. Our findings suggest that length and structure of the extracellular spacer can dictate the ability of CARs to selectively target tumor cells with high antigen density, while sparing cells with low antigen density. This study contributes to CAR construct design considerations and expands our knowledge of tuning solid tumor CAR T cell therapies for improved safety and efficacy.

Consolidation with First and Second Allogeneic Transplants in Adults with Relapsed/Refractory B-ALL Following Response to CD19CAR T Cell Therapy.

CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy has led to unprecedented rates of complete remission (CR) in children and adults with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL), yet the majority of adults relapse after initial response. One proposed method to extend the durability of remission in adults following response to CAR-T therapy is consolidation with allogeneic hematopoietic cell transplantation (alloHCT). Considering the limited published data for the utility of post CAR-T therapy consolidative alloHCT in r/r B-ALL, especially data related to patients receiving a second alloHCT, we sought to describe outcomes of patients with r/r B-ALL at our institution who received their first or second alloHCT following response to CAR-T therapy. We performed a retrospective analysis of adult patients with r/r B-ALL who responded to either investigational or standard of care (SOC) CD19-targeted CAR-T therapy and underwent consolidation with alloHCT while in CR without interim therapy. We identified 45 patients, of whom 26 (58%) and 19 (42%) received their first and second alloHCT as consolidation post CAR-T therapy, respectively. The median age was 31 years (range: 19-67) and 31 (69%) patients were Hispanic. Ph-like was the most common genetic subtype and comprised over half of cases (53%; n = 24). The median number of prior therapies pre-transplant was 5 (range: 2-7), and disease status at the time of alloHCT was CR1, CR2 or ≥CR3 in 7 (16%), 22 (49%) and 16 (35%) patients, respectively. The median time from CAR-T therapy until alloHCT was 93 (range: 42-262) days. The conditioning regimen was radiation-based myeloablative (MAC) in 22 (49%) patients. With a median follow-up of 2.47 years (range: 0.13-6.93), 2-year overall survival (OS), relapse free survival (RFS), cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) were 57.3% (95% CI: 0.432-0.760), 56.2% (95% CI: 0.562-0.745), 23.3% (95% CI: 0.13-0.42), and 20.4% (95% CI: 0.109-0.384), respectively. Two-year OS (52% vs. 68%, P = .641), RFS (54% vs. 59%, P = .820), CIR (33.5% vs. 8.5%, P = .104), and NRM (12.5% vs. 32.2%, P = .120) were not significantly different between patients who underwent their first vs. second transplant, respectively. In univariate analysis, only Ph-like genotype was associated with inferior RFS (P = .03). AlloHCT post CAR-T response is associated with a relatively low early mortality rate and encouraging survival results in high-risk adults with r/r B-ALL, extending to the second alloHCT for fit and eligible patients.

Analysis of polyfunctionality for enhanced BAFF-R CAR T-cell therapy for hematologic malignancies.

ABSTRACT: Chimeric antigen receptor (CAR) T-cell therapy has emerged as a promising immunotherapeutic strategy for eradicating human cancers. Their therapeutic success and durability of clinical responses hinges, in large part, on their functional capacity, including the ability of these engineered cells to simultaneously expand and persist after infusion into patients. CD19 CAR T-cell polyfunctionality, assessing the simultaneous functions of cytokine production, proliferation, and cytotoxicity has been reported to correlate with clinical outcomes. Assay optimization is potentially limited by the heterogeneous nature of CAR T-cell infusion products and target specificity. We optimized a single-cell platform for polyfunctionality using CAR T-cell products manufactured from healthy donors, engineered against a novel target, B-cell-activating factor receptor (BAFF-R) and validated the protocol using CD19 CAR T cells. We observed distinct qualitative differences between BAFF-R and CD19 CAR T cells relative to the proportions of stimulatory vs effector cytokines, based on target antigen density, and, generally, CD19 CAR T cells exhibited lower indices of polyfunctionality. Finally, we applied our assay to the autologous BAFF-R CAR T-cell product generated from the first patient with non-Hodgkin lymphoma treated in an ongoing clinical trial who had progressed after prior CD19 CAR T-cell therapy. We observed robust indicators of polyfunctionality, which correlated with successful CAR T-cell expansion after infusion and achievement of durable complete remission ongoing after 18 months. The precise identification of factors determining the role of BAFF-R CAR T-cell fitness in toxicity and clinical outcome will require the application of this robust assay in the analysis of additional treated patients. This trial was registered at www.ClinicalTrials.gov as #NCT05370430.

Toxicities associated with tyrosine kinase inhibitor maintenance following allogeneic hematopoietic cell transplantation in Philadelphia chromosome-positive acute lymphoblastic leukemia.

Allogeneic hematopoietic cell transplantation (HCT) offers a potential cure in Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL); nonetheless, relapses are common and the major cause of mortality. One strategy to prevent relapse is tyrosine kinase inhibitor (TKI) maintenance post-HCT, but published clinical experience is primarily with the first-generation TKI imatinib while data with newer generation TKIs are limited. We conducted a retrospective analysis of 185 Ph+ ALL patients who underwent HCT followed by TKI maintenance from 2003 to 2021 at City of Hope. Initially, 50 (27.0%) received imatinib, 118 (63.8%) received a second-generation TKI (2G-TKI), and 17 (9.2%) received ponatinib. A total of 77 patients (41.6%) required a dose reduction of their initial TKI due to toxicity. Sixty-six patients (35.7%) did not complete maintenance due to toxicity; 69 patients (37.3%) discontinued 1 TKI, and 11 (5.9%) discontinued 2 TKIs due to toxicity. Initial imatinib versus 2G-TKI versus ponatinib maintenance was discontinued in 19 (38.0%) versus 68 (57.6%) versus 3 (17.6%) patients due to toxicity (p = .003), respectively. Patients on ponatinib as their initial TKI had a longer duration of TKI maintenance versus 2G-TKI: 576.0 days (range, 72-921) versus 254.5 days (range, 3-2740; p = .02). The most common reasons for initial TKI discontinuation include gastrointestinal (GI) intolerance (15.1%), cytopenia (8.6%), and fluid retention (3.8%). The 5-year overall survival and progression-free survival for the total population were 78% and 71%, respectively. Our findings demonstrate the challenges of delivering post-HCT TKI maintenance in a large real-world cohort as toxicities leading to TKI interruptions, discontinuation, and dose reduction were common.

Brentuximab Vedotin Plus Ibrutinib in Relapsed and Refractory Hodgkin Lymphoma.

INTRODUCTION: Brentuximab vedotin (BV) is an antibody-drug conjugate that delivers monomethyl auristatin E (MMAE) to CD30+ cells and is safe and effective in relapsed/refractory (r/r) Hodgkin lymphoma (HL). Although most patients respond to BV, only a minority will obtain a complete response (CR), and almost all patients eventually progress. Ibrutinib is a Bruton's tyrosine kinase (BTK) inhibitor highly active in multiple subtypes of non-Hodgkin lymphoma; limited data exist regarding its use in HL. It irreversibly inhibits interleukin-2-inducible kinase (ITK) with Th1 based immune responses. As we previously observed preclinical synergy between ibrutinib and BV, we hypothesized ibrutinib may enhance the antitumor activity of BV in HL. We designed and conducted a phase II trial of ibrutinib plus BV in patients with R/R HL, and herein report the final primary analysis of safety and efficacy. METHODS: This was a multicenter phase II trial with a lead-in cohort in patients with r/r HL. Eligibility criteria included age ≥ 15 years with r/r HL after at least one prior line of therapy. Treatment consisted of 1.8 mg/kg BV intravenously every 3 weeks and ibrutinib 560 mg PO daily (420 mg PO daily in the lead-in cohort). Prior BV was allowed if patients were not refractory. The primary endpoint was the CR rate according to Lugano 2014. Secondary endpoints included toxicities, overall response rate (ORR), and duration of response (DOR). RESULTS: The 39 patients were enrolled onto the study, of which 67% were male; the median age was 33 (range: 17-71). 38% had extranodal disease at baseline, 51% had advanced stage disease, 51% were refractory to the prior therapy, and 21% had prior BV. Of 36 patients who were evaluable for response, the CR rate was 33% and ORR 64%; median DOR was 25.5 months. Thirteen patients proceeded to autologous transplant and 3 patients proceeded to allogeneic transplant for consolidation after response. The most common adverse events were nausea (67%), peripheral neuropathy (62%), diarrhea (59%), fatigue (46%), thrombocytopenia (46%), headache (41%), rash (41%), elevated ALT (38%), anemia (36%), vomiting (36%), abdominal pain (33%), fever (33%), and hypertension (33%). Six patients experienced unacceptable toxicity, defined as Gr 3/4 non-hematologic toxicity or non-resolving Gr 3/4 hematologic toxicity including one patient who died of multiorgan failure from suspected COVID-19 infection during cycle 1. DISCUSSION: The combination of BV and ibrutinib was active in r/r HL; however, given significant toxicity, it cannot be recommended for future development.

Simultaneous targeting of B-cell malignancies and human immunodeficiency virus with bispecific chimeric antigen receptor T cells.

Not available.

Outcomes following allogeneic hematopoietic cell transplantation relapse in Philadelphia chromosome-positive acute lymphoblastic leukemia.

Improved first progression-free survival following allogeneic hematopoietic cell transplantation relapse with the use of immunotherapy.

Flotetuzumab as a salvage immunotherapy in advanced CD123-positive hematological malignancies, a phase 1 pilot study.

CD123 "expression" is common in hematological malignancies, including acute lymphoblastic leukemia (ALL). Flotetuzumab is a novel, investigational CD3/CD123 DART®. We conducted a phase 1 study evaluating safety and efficacy of flotetuzumab in relapsed/refractory ALL (Cohort A) and other advanced CD123-positive hematological malignancies (excluding myeloid malignancies) (cohort B). Thirteen patients (9 in Cohort A and 4 in Cohort B) were treated at dose level 1 (500 ng/kg/day) before early closure due to discontinuation of drug development by sponsor. Two dose limiting toxicities (Grade 4 thrombocytopenia and neutropenia) occurred in one patient in Cohort B. Cytokine release syndrome occurred in most patients (85%), all being grade ≤2. Responses only occurred in Cohort B, with a partial response in one patient with Hodgkin's lymphoma and morphological complete remission in the bone marrow in one patient with blastic plasmacytoid dendritic cell neoplasm. In conclusion, flotetuzumab had a manageable safety profile in advanced CD123-positive hematological malignancies.

Therapy-related acute lymphoblastic leukaemia in women with antecedent breast cancer.

Therapy-related acute lymphoblastic leukaemia (tr-ALL) is a disease entity attributed to previous exposure to chemotherapy and/or radiation for antecedent malignancy. There is observed female predominance for tr-ALL, likely due to high prevalence and excellent curable rate for non-metastatic breast cancer as well as the frequent use of carcinogenic agents as part of adjuvant therapy. Here, we reviewed 37 women with diagnosis of ALL following breast cancer treatment with focus on cytogenetic categorization. Philadelphia chromosome positivity (Ph+), KMT2A alterations and other cytogenetic change groups were observed in 32%, 22% and 46% of patients respectively. Median overall survival (OS) and relapse-free survival (RFS) were 19.4 and 12.9 months, overall while both OS and RFS were superior in tr-ALL with Ph+ disease compared to KMT2Ar and other cytogenetics respectively. Seventeen (45.9%) patients underwent consolidative allogeneic haematopoietic cell transplantation (alloHCT) in CR1 out of which 4 (24%) relapsed following transplant. Both OS and RFS were superior in the KMT2Ar cytogenetics group following alloHCT. Ph chromosome represents the largest genetic entity of tr-ALL following breast cancer therapy, and it may be associated with superior survival outcomes while KMT2Ar may be associated with poorer outcomes that can perhaps be mitigated by alloHSCT.