Kenderian, Saad S.

Background: The patient/caregiver experience during CAR-T therapy is stressful, overwhelming, terrifying, and often a patient’s last treatment option. The Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery Innovation and Design team has worked with the CAR-T therapy clinical team to develop a patient experience that provides patients with a sense of caring, supportive environment, timely knowledge, and realistic expectations. Using a human-centered design approach, the Innovation and Design team worked with patients and caregivers to understand latent and unspoken needs in order to develop an ideal CAR-T therapy patient journey. Methods: With qualitative interviewing techniques, patient observation, and low fidelity experimentation, 21 patients/caregiver pairs were interviewed throughout their CAR-T therapy experience in 2018. Patients were interviewed at several touch points as well as encouraged to reach out to the Innovation and Design team at any point with reflections on their experiences. Patients were recruited as they began their evaluation phase for CAR-T therapy. The interviews were unscripted to allow for a breadth of discovery by not constraining the conversations to previously developed themes. As themes emerged from patient/caregiver interviews, artifacts and interventions were designed to alleviate pain points and improve the patient/caregiver experience. These artifacts and interventions were integrated into the clinical processes in real time and patient/caregivers were interviewed to understand the impact of these activities. Results: Several themes emerged from qualitative interviews with patients and caregivers. From the themes, interventions were developed. We were able to demonstrate a qualitative improvement in patient/caregiver experience through these interventions (Figure 1). Conclusions: Patients/caregivers undergoing CAR-T therapy have unique issues surrounding the logistics of care, emotional burden, and physical effects of treatment. We implemented processes to address these issues and observed a qualitative improvement via patient interviews/feedback. Ongoing work includes optimizing remote monitoring, digital platforms for patient education, and a quantitative study looking at patient reported outcomes (PROs) in such patients. To our knowledge, this is the first report for care delivery optimization in real-world practice for this new therapy.

Background: Unprecedented clinical outcomes were reported after CD19 chimeric antigen receptor T-cell (CART19) therapy. However, the complete response rate in chronic lymphocytic leukemia (CLL) is much lower, at approximately 20%–30%. Several immune defects have been identified in CLL that result from the complex interaction between CLL cells and the microenvironment. This leukemic microenvironment is rich with extracellular vesicles (EVs) secreted by B-CLL cells. Here, we aimed to investigate the role of EVs play in the diminished CART response seen in some CLL patients. Methods: EVs were isolated from peripheral blood of 16 patients with untreated CLL at different Rai stages and risk profile by FISH. Cytometry was used to determine size, number of particles per μl, and CD19 expression. To investigate the impact of EVs on CAR T-cell functions, CART19 cells were stimulated with either CLL B cells or the CD19-positive cell line JEKO and different effector functions were analyzed. Results: Two patterns of EVs in CLL patients were identified; a single versus 2 distinct EV populations, characterized by size (small [EVssmall] and large [EVslarge], Fig 1A). In 25% of patients, EVs were CD19 positive (EVCD19+). CD19 positivity was detected only in patients with the EVslarge (Fig 1B). The EVs concentration, CD19 expression (EVsCD19+ vs EVsCD19-), or the size (EVssmall vs EVslarge) did not correlate with disease stage (early vs advanced Rai stage) or risk profile of CLL (low vs high risk). To investigate our hypothesis that EVs could modulate CART19 function, CART19 cell effector functions were examined in the presence of EVsCD19+, EVsCD19-, EVssmall, or EVslarge. EVs alone were insufficient to stimulate CART19 cells. However when CART19 cells were stimulated with the CD19-positive cell line JEKO, their effector functions were reduced only in the presence of EVsCD19+ but not EVsCD19-. This included a significant reduction in CART-specific killing (Fig 1C) and a reduction in cytokine production. The impairment of CART cell functions was independent of the size of EVs, ie, there was no impairment of CART functions with large or small size EVCD19- in co-culture. Conclusion: We identify CD19-positive large size EVs from patients with CLL and demonstrate that these EVs play a role in the leukemic microenvironment by reducing CAR T-cell activity. Studies are ongoing to define the mechanism(s).

The prevalence, clinicopathologic correlates, and outcomes of previously untreated chronic lymphocytic leukemia (CLL) patients with IGH‐BCL2 and IGH‐BCL3 translocations are not well known. Using the Mayo Clinic CLL database, we identified patients seen between March 1, 2002 and September 30, 2016 who had FISH testing performed within 3 years of CLL diagnosis. The prognostic profile, time to first therapy (TTT), and overall survival (OS) of patients with IGH‐BCL2 and IGH‐BCL3 translocation were compared to patients without these abnormalities (non‐IGH group). Of 1684 patients who met the inclusion criteria, 38 (2.2%) had IGH‐BCL2, and 16 (0.9%) had IGH‐BCL3 translocation at diagnosis. Patients with IGH‐BCL3 translocation were more likely to have high and very‐high CLL‐International Prognostic Index, compared to patients with IGH‐BCL2 translocation and the non‐IGH group. The 5‐year probability of requiring therapy was significantly higher for IGH‐BCL3 compared to IGH‐BCL2 and non‐IGH groups (84% vs 33% vs 29%, respectively, P < 0.0001). The 5‐year OS was significantly shorter for IGH‐BCL3 compared to IGH‐BCL2 and non‐IGH groups (45% vs 89% vs 86%, respectively, P < 0.0001). On multivariable analyses, IGH‐BCL3 translocation was associated with a shorter TTT (hazard ratio [HR] = 2.7; P = 0.005) and shorter OS (HR = 5.5; P < 0.0001); IGH‐BCL2 translocation did not impact TTT and OS. In conclusion, approximately 3% of all newly diagnosed CLL patients have either an IGH‐BCL2 or IGH‐BCL3 translocation. Patients with IGH‐BCL3 translocations have a distinct prognostic profile and outcome. These results support the inclusion of an IGH probe during the routine evaluation of FISH abnormalities in newly diagnosed CLL.

Abstract Chimeric antigen receptor T (CAR-T) cell therapy is a new pillar in cancer therapeutics; however, its application is limited by the associated toxicities. These include cytokine release syndrome (CRS) and neurotoxicity. Although the IL-6R antagonist tocilizumab is approved for treatment of CRS, there is no approved treatment of neurotoxicity associated with CD19-targeted CAR-T (CART19) cell therapy. Recent data suggest that monocytes and macrophages contribute to the development of CRS and neurotoxicity after CAR-T cell therapy. Therefore, we investigated neutralizing granulocyte-macrophage colony-stimulating factor (GM-CSF) as a potential strategy to manage CART19 cell–associated toxicities. In this study, we show that GM-CSF neutralization with lenzilumab does not inhibit CART19 cell function in vitro or in vivo. Moreover, CART19 cell proliferation was enhanced and durable control of leukemic disease was maintained better in patient-derived xenografts after GM-CSF neutralization with lenzilumab. In a patient acute lymphoblastic leukemia xenograft model of CRS and neuroinflammation (NI), GM-CSF neutralization resulted in a reduction of myeloid and T cell infiltration in the central nervous system and a significant reduction in NI and prevention of CRS. Finally, we generated GM-CSF–deficient CART19 cells through CRISPR/Cas9 disruption of GM-CSF during CAR-T cell manufacturing. These GM-CSFk/o CAR-T cells maintained normal functions and had enhanced antitumor activity in vivo, as well as improved overall survival, compared with CART19 cells. Together, these studies illuminate a novel approach to abrogate NI and CRS through GM-CSF neutralization, which may potentially enhance CAR-T cell function. Phase 2 studies with lenzilumab in combination with CART19 cell therapy are planned.

SummaryThe effects of ibrutinib on the natural history of autoimmune cytopenias (AIC) among chronic lymphocytic leukaemia (CLL) patients treated in routine clinical practice require further investigation. Using the Mayo Clinical CLL Database, 193 CLL patients treated with ibrutinib between November 2013 and January 2017 outside the context of a clinical trial were identified; complete review of their medical records was performed for details of past history of AIC and treatment‐emergent AIC. We identified 29/193 (15%) patients with history of AIC prior to ibrutinib start. Of 12 patients requiring AIC therapy at ibrutinib start, 8 (67%) were able to discontinue or de‐escalate AIC treatment, and no patient had worsening of their AIC after initiating ibrutinib. Eleven (6%) patients developed treatment‐emergent AIC after a median of 59 (range, 6–319) days following the initiation of ibrutinib, 7 of whom (64%) were able to continue ibrutinib. Overall and event‐free survival from time of ibrutinib start were not significantly different between patients with history of AIC and those with no history of AIC. Treatment‐emergent AIC were seen exclusively in patients with unmutated IGHV and were associated with a shorter EFS. These results suggest a low rate of treatment‐emergent AIC and improvement in patients with existing AIC.

AbstractThe prevalence of liver dysfunction and its association with outcomes in patients with previously untreated chronic lymphocytic leukemia (CLL) is unknown. Newly diagnosed (<12 months) previously untreated CLL patients seen at Mayo Clinic, Rochester, MN between 9/1993 and 4/2016 who had baseline assessment of at least one liver function test (LFT) were included in this analysis. The prevalence of liver dysfunction at baseline, proportion of patients who acquired LFT abnormalities, time to first therapy (TTFT) and overall survival (OS) were assessed. An abnormal LFT was present in 82/2336 (3.5%) patients at diagnosis and was associated with advanced Rai stage (Rai III–IV) (21% vs. 6%; P < .001), lower hemoglobin (13.1 g/dL vs. 13.9 g/dL; P < .001), and lower platelet count (187 × 109/L vs. 200 × 109/L; P = .03). Additionally, 236 patients with normal LFTs at diagnosis developed acquired liver dysfunction during follow‐up. Patients with abnormal LFTs at diagnosis had a shorter OS compared to those with normal LFTs (HR 1.80 95% CI 1.13‐2.87; P = .014, adjusted for age, sex, Rai stage, and treatment), although TTFT was not different. Of 52 patients who underwent a liver biopsy, CLL was present in liver tissue in 39/52 (73%) patients, with the portal tracts the most common region involved. Histopathology findings of liver involvement by CLL had limited correlation with choice of CLL therapy. In conclusion, approximately 1 of 25 newly diagnosed CLL patients has abnormal LFTs at diagnosis. Although the TTFT was not different among patients with abnormal LFTs, these patients have a shorter OS compared to those with normal LFTs.

Abstract Chimeric antigen receptor (CAR) T cell immunotherapy has demonstrated profound results in hematologic malignancies but clinical efficacy in the solid tumor setting has not been observed. Barriers to T cell entry and function may partially explain this observation. As solid tumors actively recruit myeloid cells, we hypothesized that macrophages have the potential to be a powerful cellular immunotherapeutic agent in this setting if properly activated and redirected. We here describe the development of CAR macrophages (CARMA), demonstrating the feasibility, mechanism, and efficacy of this platform. To examine the function of CARs in macrophages, first generation anti-CD19, anti-mesothelin, or anti-HER2 CARs with a CD3ζ intracellular domain were introduced into the THP1 macrophage model. In vitro function was assessed via quantitative phagocytosis and luciferase-based specific killing assays. CARMA selectively phagocytosed and cleared cognate antigen-bearing tumor cells. To demonstrate the requirement for CAR-mediated intracellular signaling for activity, a CD3ζ-null CAR construct was tested in vitro. The deletion of CD3ζ significantly reduced the phagocytic and killing capacity (p&lt;0.01) of CARMA. We identified Ad5f35, a chimeric adenovirus, as a novel and highly efficient viral vector for the transduction of normal donor and cancer patient macrophages (&gt;70% CAR expression). Ad5f35 transduction polarized human macrophages toward a durable immunostimulatory M1 phenotype and rendered CARMA resistant to subversion toward the immunosuppressive M2 phenotype, as defined by surface markers and metabolomics. CARMA enhanced the proliferative capacity of CD8+ T cells in phytohemagglutinin activation assays and secreted factors that activated by-stander macrophages. Primary human anti-HER2 CARMA demonstrated targeted phagocytosis and killing of HER2 expressing ovarian and breast cancer cell lines, and exhibited a six-fold higher luciferase-based killing capacity of SKOV3 cells compared to trastuzumab in vitro (p=0.002). Anti-HER2 CARMA was evaluated in vivo in an intraperitoneal (IP) SKOV3 ovarian cancer xenograft model. Mice that received IP CARMA had a decrease in tumor burden of approximately two orders of magnitude and had a 30-day survival benefit relative to untreated or control macrophage treated mice (p=0.018). In a systemically disseminated SKOV3 model, a single dose of IV CARMA led to a durable anti-tumor response (38-fold reduction relative to control on day 31 post-treatment; p=0.016) Lastly, we demonstrated that the blockade of the anti-phagocytic CD47/SIRPα axis enhanced the phagocytic capacity of CARMA. In summary, we here demonstrate that human macrophages engineered with a CAR exhibit targeted anti-tumor function in both in vitro and in vivo preclinical models. This novel cellular immunotherapeutic approach has a clear translational potential for the treatment of solid tumors. Citation Format: Michael Klichinsky, Marco Ruella, Olga Shestova, Saad S. Kenderian, Miriam Y. Kim, Roddy O'Connor, John Scholler, Carl June, Saar Gill. Chimeric antigen receptor macrophages (CARMA) for adoptive cellular immunotherapy of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4575. doi:10.1158/1538-7445.AM2017-4575