Treatment of secondary CNS lymphoma using CD19-targeted chimeric antigen receptor (CAR) T cells.

BACKGROUND: Aggressive B cell lymphoma with secondary central nervous system (CNS) involvement (SCNSL) carries a dismal prognosis. Chimeric antigen receptor (CAR) T cells (CAR-T) targeting CD19 have revolutionized the treatment for B cell lymphomas; however, only single cases with CNS manifestations successfully treated with CD19 CAR-T have been reported. METHODS: We prospectively enrolled 4 patients with SCNSL into our study to assess clinical responses and monitor T cell immunity. RESULTS: Two of four SNCSL patients responded to the CD19-targeted CAR-T. Only one patient showed a substantial expansion of peripheral (PB) CAR-T cells with an almost 100-fold increase within the first week after CAR-T. The same patient also showed marked neurotoxicity and progression of the SNCSL despite continuous surface expression of CD19 on the lymphoma cells and an accumulation of CD4+ central memory-type CAR-T cells in the CNS. Our studies indicate that the local production of chemokine IP-10, possibly through its receptor CXCR3 expressed on our patient's CAR-T, could potentially have mediated the local accumulation of functionally suboptimal anti-tumor T cells. CONCLUSIONS: Our results demonstrate expansion and homing of CAR-T cells into the CNS in SNCSL patients. Local production of chemokines such as IP-10 may support CNS infiltration by CAR-T cells but also carry the potential of amplifying local toxicity. Future studies investigating numbers, phenotype, and function of CAR-T in the different body compartments of SNSCL patients receiving CAR-T will help to improve local delivery of "fit" and highly tumor-reactive CAR-T with low off-target reactivity into the CNS.

A novel multicolor fluorescent spot assay for the functional assessment of chimeric antigen receptor (CAR) T-cell products.

BACKGROUND AIMS: Chimeric antigen receptor (CAR) T-cell (CAR-T) therapies have revolutionized the treatment of B-cell lymphomas. Unfortunately, relapses after CD19-targeted CAR-T are relatively common and, therefore, there is a critical need for assays able to assess the function and potency of CAR-T products pre-infusion, which will hopefully help to optimize CAR-T therapies. We developed a novel multicolor fluorescent spot assay (MFSA) for the functional assessment of CAR-T products on a single-cell level, combining the numerical assessment of CAR-T products with their functional characterization. METHODS: We first used a standard single-cell interferon (IFN)-γ enzyme-linked immune absorbent spot assay to measure CD19-targeted CAR-T responses to CD19-coated beads. We then developed, optimized and validated an MFSA that simultaneously measures the secretion of combinations of different cytokines on a single CAR-T level. RESULTS: We identified IFN-γ/tumor necrosis factor-α/granzyme B as the most relevant cytokine combination, and we used our novel MFSA to functionally and numerically characterize two clinical-grade CAR-T products. CONCLUSIONS: In conclusion, we have developed a novel assay for the quantitative and functional potency assessment of CAR-T products. Our optimized MFSA is cost-effective, easy to perform, reliable, can be performed overnight, allowing for a fast delivery of the product to the patient, and requires relatively minimal maintenance and training. The clinical value of our novel assay will be assessed in studies correlating the pre-infusion assessment of CAR-T products with the patients' outcome in a prospective fashion.

Imaging Biomarkers to Predict Outcomes in Patients With Large B-Cell Lymphoma With a Day 28 Partial Response by 18F-FDG PET/CT Imaging Following CAR-T Therapy.

BACKGROUND: CD19 directed CAR-T therapy for Large B-cell lymphoma (LBCL) has shown great therapeutic response in patients with relapsed/refractory disease with response rates of 60-80%. However, in patients with a partial response (PR) on initial day 28 post CAR-T therapy imaging, clinical uncertainty remains as half of these patients will ultimately have relapsed disease.   PATIENTS: In 24 patients receiving CD19 directed CAR-T therapy for relapsed/refractory LBCL achieving a PR on day 28, we utilize imaging biomarkers by 18F-FDG PET/CT imaging at pre CAR-T therapy baseline and day 28 to determine factors that may predict best overall response (B-OR), progression free survival (PFS), and overall survival (OS).   METHODS: Out of 75 patients receiving CAR-T therapy at a single institution, we retrospectively identified and reviewed 25 (33%) as achieving a PR on day 28. PR was defined using the 2014 Lugano classification system. All patients received standard of care CD19 directed CAR-T therapy with axicabtagene ciloleucel. Two independent nuclear medicine physicians measured baseline (pre-CAR-T therapy) and day 28 PET/CT SUVmax, SUVmean and TMV (cm3) of each lesion (node, organ or marrow uptake, if any) using ROVER software. All statistical tests were two-sided and conducted at the 0.05 level of significance. R version 1.3.1099 (R-studio) was used for statistical modeling.   CONCLUSION: We demonstrate that a higher day 28 SUVmax was significantly higher in those with a B-OR of PR and in our modeling, a lower day 28 SUVmax may predict favorable PFS and OS. Additionally, lower TMV, both at baseline and day 28, may also be predictive of longer PFS and OS, while lower TLG at baseline, but not day 28 is significantly associated with a B-OR of CR. While further study is warranted, these imaging biomarkers may allow for early identification of those with a day 28 PR at highest risk for relapse leading to early intervention to improve long term outcomes.

Chimeric antigen receptor (CAR) T cells for the treatment of a kidney transplant patient with post-transplant lymphoproliferative disorder (PTLD).

Post-transplant lymphoproliferative disorder (PTLD) is a potentially fatal complication following kidney transplantation, and there is a critical and unmet need for PTLD treatments associated with more pronounced and durable responses. To date, reports on the use of CD19-targeted chimeric antigen receptor (CAR) T (CAR-T) cells in patients after solid organ transplant (SOT) have been anecdotal, clinical presentations and outcomes have been heterogenous, and a longitudinal analysis of CAR-T cell expansion and persistence in PTLD patients has not been reported. Our report describes a patient with a history of renal transplant who received CD19-directed CAR-T cell therapy for the treatment of refractory PTLD, diffuse large B cell lymphoma (DLBCL)-type. We show that even with the background of prolonged immunosuppression for SOT, it is possible to generate autologous CAR-T products capable of expansion and persistence in vivo, without evidence of excess T-cell exhaustion. Our data indicate that CAR-T cells generated from a SOT recipient with PTLD can yield deep remissions without increased toxicity or renal allograft dysfunction. Future clinical studies should build on these findings to investigate CAR-T therapy, including longitudinal monitoring of CAR-T phenotype and function, for PTLD in SOT recipients.

Outcomes of Busulfan, Fludarabine, and 400 cGy Total Body Irradiation Compared With Busulfan and Fludarabine Reduced-Intensity Conditioning Regimens for Allogeneic Stem Cell Transplantation in Adult Patients With Hematologic Diseases: A Single-Center Experience.

BACKGROUND: Reduced intensity conditioning (RIC) regimens decrease the risk for nonrelapse mortality (NRM) in adult patients undergoing allogeneic hematopoietic stem cell transplantation for hematologic malignancies but increase the risk for relapse. The aim of this study was to compare the outcomes of fludarabine-total body irradiation (TBI) with fludarabine among patients with hematologic diseases. PATIENTS AND METHODS: This retrospective study of 137 patients with different hematologic malignancies compared the outcomes of 63 patients who received a conventional RIC regimen with 2 days of IV busulfan (3.2 mg/kg/d × 2 days) and fludarabine with 74 patients who received the same regimen plus 400 cGy of fludarabine and busulfan (FB)-TBI divided in 2 doses over 1 day (200 cGy BID). Median follow-up was 4.62 years. RESULTS: The donors were either HLA-matched siblings (36%) or HLA-matched unrelated donors (64%). The FB-TBI showed trends toward improvement in progression-free survival (PFS) and overall survival (OS) over FB (5-year PFS rates 50% vs 34%, P = .06, and 5-year OS rate 53% vs 39%, P = .13). Acute graft-vs-host disease (aGVHD), relapse, and NRM were similar between the 2 groups. The 5-year cumulative incidence of chronic GVHD (cGVHD) was lower in the FB-TBI group compared with the FB group (29% vs 52%, P = .003). Multivariable analysis revealed that grade III-IV aGVHD was the only independent risk factor for worse OS (P = .001) in both groups. A high disease risk index was possibly associated with inferior OS (P = .07) in both groups. CONCLUSIONS: The FB-TBI is a safe and effective intensified RIC regimen for adult patients with hematologic malignancies. It predicted a lower risk for cGVHD and showed possibly improved PFS and OS compared with FB.

Three-Year Outcomes in Recipients of Mismatched Unrelated Bone Marrow Donor Transplants Using Post-Transplantation Cyclophosphamide: Follow-Up from a National Marrow Donor Program-Sponsored Prospective Clinical Trial.

The use of post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis has resulted in reductions in GVHD and improved outcomes in allogeneic hematopoietic cell transplantation (HCT) using HLA-mismatched related donors. We report the 3-year outcomes of the first multicenter prospective clinical trial using PTCy in the setting of mismatched unrelated donor (MMUD) bone marrow HCT. The study enrolled 80 patients, treated with either myeloablative conditioning (MAC; n = 40) or reduced-intensity conditioning (RIC; n = 40), with the primary endpoint of 1-year overall survival (OS). The median follow-up for this study was 34 months (range, 12 to 46 months) in the RIC group and 36 months (range, 18 to 49 months) in the MAC group. Three-year OS and nonrelapse mortality were 70% and 15%, respectively, in the RIC group and 62% and 10% in the MAC group. No GVHD was reported after 1 year. The incidence of relapse was 29% in the RIC group and 51% in the MAC group. OS did not differ based on HLA match grade (63% in the 7/8 strata and 71% in the 4 to 6/8 strata). These encouraging outcomes, which were sustained for 3 years post-HCT, support the continued exploration of MMUD HCT using a PTCy platform. Important future areas to address include relapse reduction and furthering our understanding of optimal donor selection based on HLA and non-HLA factors.

Ocular adverse events associated with chimeric antigen receptor T-cell therapy: a case series and review.

BACKGROUND/AIMS: Chimeric antigen receptor T-cell (CAR T) therapy has been shown to improve the remission rate and survival for patients with refractory haematological malignancies. The aim of this study is to describe ocular adverse effects associated with CAR T therapy in patients with haematological malignancies. METHODS: This is a retrospective, single-institution, case series. Patients aged 18 years or older who received standard of care CAR T therapy for relapsed/refractory large B-cell lymphoma with a documented ophthalmic evaluation were included. The primary outcome was clinician ophthalmic examination findings. RESULTS: A total of 66 patients received CAR T-cell therapy from February 2018 to October 2019 with 11 receiving an ophthalmic examination. Eleven patients (n=22 eyes) who received CAR T-cell therapy were included in review. The median time from CAR T-cell infusion date to ocular examination was 57.5 days. The median patient age at the time of examination was 60.5 years. Ten patients had subjective symptoms prompting ophthalmic examination. Two patients reported floaters and photopsias. One patient had worsening ocular graft-versus-host disease. Two patients were identified with possible reactivation of viral infections, including herpes zoster ophthalmicus and regressing acute retinal necrosis. CONCLUSIONS: The increasing use of CAR T therapy for malignancies underscores the importance of ophthalmologists and oncologists understanding the potential toxicities associated with its use, particularly ocular toxicities and when to refer for an ophthalmic examination.

T cell responses against SARS-CoV-2 and its Omicron variant in a patient with B cell lymphoma after multiple doses of a COVID-19 mRNA vaccine.

Anti-SARS-CoV-2 antibodies are crucial for protection from future COVID-19 infections, limiting disease severity, and control of viral transmission. While patients with the most common type of hematologic malignancy, B cell lymphoma, often develop insufficient antibody responses to messenger RNA (mRNA) vaccines, vaccine-induced T cells would have the potential to 'rescue' protective immunity in patients with B cell lymphoma. Here we report the case of a patient with B cell lymphoma with profound B cell depletion after initial chemoimmunotherapy who received a total of six doses of a COVID-19 mRNA vaccine. The patient developed vaccine-induced anti-SARS-CoV-2 antibodies only after the fifth and sixth doses of the vaccine once his B cells had started to recover. Remarkably, even in the context of severe treatment-induced suppression of the humoral immune system, the patient was able to mount virus-specific CD4+ and CD8+ responses that were much stronger than what would be expected in healthy subjects after two to three doses of a COVID-19 mRNA vaccine and which were even able to target the Omicron 'immune escape' variant of the SARS-CoV-2 virus. These findings not only have important implications for anti-COVID-19 vaccination strategies but also for future antitumor vaccines in patients with cancer with profound treatment-induced immunosuppression.

Humoral immunity against SARS-CoV-2 variants including omicron in solid organ transplant recipients after three doses of a COVID-19 mRNA vaccine.

Objectives: Solid organ transplant recipients (SOTR) receiving post-transplant immunosuppression show increased COVID-19-related mortality. It is unclear whether an additional dose of COVID-19 vaccines can overcome the reduced immune responsiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. Methods: We analysed humoral immune responses against SARS-CoV-2 and its variants in 53 SOTR receiving SARS-CoV-2 vaccination. Results: Following the initial vaccination series, 60.3% of SOTR showed no measurable neutralisation and only 18.9% demonstrated neutralising activity of > 90%. More intensive immunosuppression, antimetabolites in particular, negatively impacted antiviral immunity. While absolute IgG levels were lower in SOTR than controls, antibody titres against microbial recall antigens were higher. By contrast, SOTR showed reduced vaccine-induced IgG/IgA antibody titres against SARS-CoV-2 and its delta variants and fewer linear B-cell epitopes, indicating reduced B-cell diversity. Importantly, a third vaccine dose led to an increase in anti-SARS-CoV-2 antibody titres and neutralising activity across alpha, beta and delta variants and to the induction of anti-SARS-CoV-2 CD4+ T cells in a subgroup of patients analysed. By contrast, we observed significantly lower antibody titres after the third dose with the omicron variant compared to the ancestral SARS-CoV-2 and the improvement in neutralising activity was much less pronounced than for all the other variants. Conclusion: Only a small subgroup of solid organ transplant recipients is able to generate functional antibodies after an initial vaccine series; however, an additional vaccine dose resulted in dramatically improved antibody responses against all SARS-CoV-2 variants except omicron where antibody responses and neutralising activity remained suboptimal.

Low utility of the H-Score and HLH-2004 criteria to identify patients with secondary hemophagocytic lymphohistiocytosis after CAR-T cell therapy for relapsed/refractory diffuse large B-Cell lymphoma.

Secondary hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune dysregulation disorder. Use of chimeric antigen receptor T-cell therapy (CAR-T) is associated with cytokine release syndrome (CRS), Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS) and secondary HLH. However, application of HLH scoring systems (H-score, HLH-2004 criteria) are not validated in this setting. We analyzed the utility of applying the H-score and the HLH-2004 criteria to identify patients with possible HLH post-CAR-T for Relapsed/Refractory Diffuse Large B-cell Lymphoma. Only two of four patients with post CAR-T HLH met five or more of the diagnostic criteria for HLH by HLH 2004 criteria. In contrast all four post CAR-T HLH patients had a high H-score (>169); however, an additional ten patients that did not have HLH also had a high H-score. Thus, in this patient population, both scoring systems were demonstrated to have low prognostic significance in differentiating between high grade CRS and HLH.

The impact of bridging therapy prior to CD19-directed chimeric antigen receptor T-cell therapy in patients with large B-cell lymphoma.

In the relapsed/refractory setting for treatment of large B-cell lymphoma (LBCL), chimeric antigen receptor T-cell (CAR-T) therapy has emerged as an effective treatment modality. Patients often have aggressive disease that requires prompt treatment in the form of bridging therapy (BT) for disease stabilisation while CAR-T cells are manufactured. Patients (n = 75) undergoing CAR-T therapy infusion for LBCL at our institution were identified. A total of 52 (69·3%) received BT and 23 (30·7%) received no BT (NBT). BT modalities included systemic BT (SBT) in 28 patients, radiation BT (RBT) in 14, and high-dose steroid BT (HDS) in 10. There was no difference in incidence of cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome between BT and NBT (P = 0·18 and P = 0·53 respectively). Prolonged cytopenias at Day 180 were more common in BT than NBT (50% vs. 13·3%, P = 0·04). The SBT and RBT subgroups had more cytopenias at Day 180 compared to the HDS and NBT subgroups (58·3% and 57·1% vs. 20% and 13·3% respectively, P = 0·04). Disease response at last follow-up, progression-free survival and overall survival were similar between BT, NBT, and BT subgroups. In summary, BT can be safely considered in patients undergoing CAR-T therapy. However, those undergoing BT with SBT or RBT are at higher risk of prolonged cytopenias after CAR-T therapy.

Anti-SARS-CoV-2 Immune Responses in Patients Receiving an Allogeneic Stem Cell or Organ Transplant.

Patients after autologous (autoSCT) and allogeneic stem cell transplantation (alloSCT) are at an increased risk of COVID-19-related morbidity and mortality, compounded by an immune system weakened by the underlying malignancy and prior treatments. Allogeneic transplantation, including stem cell and solid organ transplants, requires intensive immunosuppressive prophylaxis, which may further undermine the development of a protective vaccine-induced anti-viral immunity. Herein, we report on short- and long-term antiviral immune responses in two peri-stem cell transplant recipients and a third patient who received a COVID-19 vaccination after kidney transplantation. Our data indicate that: (1) patients post-alloSCT may be able to mount an anti-COVID-19 immune response; however, a sufficient time interval between transplant and exposure may be of critical importance; (2) alloSCT recipients with preexisting anti-SARS-CoV-2 immunity are at risk for losing protective humoral immunity following transplantation, particularly if the stem-cell donor lacks antiviral immunity, e.g., vaccine-derived immunity; and (3) some post-transplant patients are completely unable to build an immune response to a COVID-19 vaccine, perhaps based on the prophylactic suppression of T cell immunity.

National Marrow Donor Program-Sponsored Multicenter, Phase II Trial of HLA-Mismatched Unrelated Donor Bone Marrow Transplantation Using Post-Transplant Cyclophosphamide.

PURPOSE: Hematopoietic cell transplantation (HCT) is curative for hematologic disorders, but outcomes are historically inferior when using HLA-mismatched donors. Despite unrelated donor registries listing > 38 million volunteers, 25%-80% of US patients lack an HLA-matched unrelated donor, with significant disparity across ethnic groups. We hypothesized that HCT with a mismatched unrelated donor (MMUD) using post-transplant cyclophosphamide (PTCy), a novel strategy successful in overcoming genetic disparity using mismatched related donors, would be feasible and increase access to HCT. PATIENTS AND METHODS: We performed a prospective phase II study of MMUD bone marrow HCT with PTCy for patients with hematologic malignancies. The primary end point was 1-year overall survival (OS), hypothesized to be 65% or better. 80 patients enrolled at 11 US transplant centers (December 2016-March 2019). Following myeloablative or reduced-intensity conditioning-based HCT, patients received PTCy on days +3, +4, with sirolimus and mycophenolate mofetil starting on day +5. We compared outcomes to Center for International Blood and Marrow Transplant Research contemporary controls receiving PTCy. RESULTS: Notably, 48% of patients enrolled were ethnic minorities. 39% of pairs were matched for 4-6 out of 8 HLA alleles. The primary end point was met, with 1-year OS of 76% (90% CI, 67.3 to 83.3) in the entire cohort, and 72% and 79% in the myeloablative and reduced-intensity conditioning strata, respectively. Secondary end points related to engraftment and graft-versus-host-disease were reached. Multivariate analysis comparing the study group with other mismatched HCT controls found no significant differences in OS. CONCLUSION: Our prospective study demonstrates the feasibility and effectiveness of HCT with an MMUD in the setting of PTCy. Remarkably, nearly half of the study participants belonged to an ethnic minority population, suggesting this approach may significantly expand access to HCT.

Immune effector cell-associated neurotoxicity syndrome after chimeric antigen receptor T-cell therapy for lymphoma: predictive biomarkers and clinical outcomes.

BACKGROUND: CD19-directed chimeric antigen receptor (CAR) T-cell therapy (CAR-T) has emerged as effective for relapsed/refractory large B-cell lymphoma (R/R LBCL). The neurologic toxicity seen with CAR-T, referred to as immune effector cell-associated neurotoxicity syndrome (ICANS), is poorly understood. To better elucidate the clinical characteristics, treatment outcomes, and correlative biomarkers of ICANS, we review here a single-center analysis of ICANS after CAR T-cell therapy in R/R LBCL. METHODS: Patients (n = 45) with R/R LBCL treated with axicabtagene ciloleucel (axi-cel) were identified. Data regarding treatment course, clinical outcomes, and correlative studies were collected. Patients were monitored and graded for ICANS via CARTOX-10 scoring and Common Terminology Criteria for Adverse Events (CTCAE) v4.03 criteria, respectively. RESULTS: Twenty-five (56%) patients developed ICANS, 18 (72%) of whom had severe (CTCAE grades 3-4) ICANS. Median time to development of ICANS was 5 days (range, 3-11). Elevated pre-infusion (day 0 [D0]) fibrinogen (517 vs 403 mg/dL, upper limit of normal [ULN] 438 mg/dL, P = 0.01) and D0 lactate dehydrogenase (618 vs 506 units/L, ULN 618 units/L, P = 0.04) were associated with ICANS. A larger drop in fibrinogen was associated with ICANS (393 vs 200, P < 0.01). Development of ICANS of any grade had no effect on complete remission (CR), progression-free survival (PFS), or overall survival (OS). Duration and total dose of steroid treatment administered for ICANS did not influence CR, PFS, or OS. CONCLUSIONS: ICANS after CAR-T with axi-cel for R/R LBCL was seen in about half of patients, the majority of which were high grade. Contrary to previous reports, neither development of ICANS nor its treatment were associated with inferior CR, PFS, or OS. The novel finding of high D0 fibrinogen level can identify patients at higher risk for ICANS.

Toxoplasma-induced hemophagocytic lymphohistiocytosis after haploidentical allogeneic stem cell transplantation.

Hemophagocytic lymphohistiocytosis (HLH) is a disorder of immune regulation, manifested by fever, pancytopenia, hyperferritiniemia, hypertriglyceridemia, and extensive hemophagocytosis involving the bone marrow and spleen. HLH can occur in adults with an underlying hematopoietic malignancy, or with systemic infections. HLH following hematopoietic stem cell transplantation (HSCT) is unusual, and the diagnosis may be challenging particularly because the diagnostic criteria in the HLH-2004 guidelines overlap with common post-transplant complications such as engraftment syndrome, graft-vs-host disease, and infections. HLH is commonly triggered by viral, bacterial and, less commonly, parasitic infections. Following HSCT, patients with latent Toxoplasma infection may develop systemic disease secondary to reactivation, and rarely this may lead to a HLH physiology, with a very high mortality rate. Herein we describe the successful management of disseminated toxoplasmosis associated with life-threatening HLH using tocilizumab and antimicrobial therapy.