Background: High risk AML patients (pts) have poor outcome with low complete remission (CR) rate and long term survival despite intensive chemotherapy.
Tyrosine kinases play an important role in AML ...pathogenesis. Pre-clinical studies performed in our center (Blood. 2013 122:1900) have shown that Src family tyrosine kinases (SFK) including Lyn, Hck and Fgr are abnormally activated in AML compared to normal hematopoietic stem cell and progenitor cells. Other studies have shown that the c-Kit receptor is over-activated in a subset of AML pts and contributes to abnormal leukemia cell growth. We further show that the small molecule SFK and c-Kit inhibitor dasatinib reduces proliferation and survival of AML stem and progenitor cells. Importantly, dasatinib enhances the sensitivity of AML stem and progenitor cells to chemotherapeutic agents by inhibiting Akt signaling, increasing mdm2 phosphorylation and enhancing p53 activity in AML cells. Based on this data we conducted a phase I/II clinical study of the combination of dasatinib with conventional cytarabine-idarubicin ("7+3")-based induction chemotherapy in high-risk AML.
Methods: Between September 20013 and July 2015, 18 adult AML pts were enrolled in the study. Eligibility criteria were high-risk AML, age >18 years, and suitability for intensive therapy. High risk AML was defined by one of the following criteria: older age (> 60 yrs), poor-risk cytogenetic and molecular abnormalities (ELN criteria), secondary disease (AML evolving from myelodysplasia or myeloproliferative neoplasm), therapy related (t-AML), or relapsed/refractory.
This Phase I study used a 3 + 3 dose escalation design for dasatinib while keeping a fixed dose of cytarabine and idarubicin (cytarabine 200 mg/m2 CIV days 1-7, idarubicin 12 mg/m2 IV days 1-3). Dasatinib was started at a dose of 70 mg (dose level 1; DL-1) days 1-7, and escalated to 100 mg orally days 1-7 (DL 1). Pts who failed to achieve CR received second re-induction with the same regimen. Pts who achieved CR received consolidation high dose cytarabine and/or allogeneic stem cell transplantation (SCT) based on donor availability.
Results: Of the 18 pts enrolled on the study, 7 pts (39%) had secondary AML, 5 pts (28%) relapsed AML, 2 pts (11%) t-AML, and 4 (22%) were newly diagnosed older AML pts (one with complex karyotype, one with trisomy 8 and one cytogenetically normal with FTL3-ITD). The median age of all pts was 62 yrs (range 27-73). Of the 18 pts, 13 pts are currently evaluable for response; of which 10 (77%) achieved CR/Cri. Of the 5 non-evaluable pts, one pt withdrew from study after 2 days of therapy, one pt was taken off study after 3 days due to cytarabine neurotoxicity, one pt died of intracranial hemorrhage before the day 14 bone marrow biopsy, one pt had therapy interrupted secondary to pneumonia and sepsis, and one is still receiving therapy. None of the pts required more than one induction to achieve CR. Of the 10 pts who achieved CR/Cri, 8 patients went on to receive allogeneic SCT. As expected, the most commonly reported grade 3 and 4 adverse events (AE) were anemia 50%, thrombocytopenia 44%, neutropenia 38%, and fatigue 27%. The most common grade 1-2 AE were GI toxicities 61% and rash 33%.
Correlative studies performed on blood samples obtained from pts on day 3 after initiation of treatment (n=9) demonstrated significant decrease in of SRC activity (as indicated by reduction in phospho-SRC levels on immunoblotting, 0.52±0.11 of control, p=0.01), and increased expression of p53-target genes as evaluated by Q-RT-PCT including Puma (16.2±6.9 fold, p=0.015), P21 (4.9±1.1 fold, p=0.004), DR5 (3.4±0.9, p=0.004), Bax (3.7±0.9 fold, p=0.001) and HDM2 (2.1±0.5, p=0.02).
Conclusion: Combination of dasatinib with conventional "7+3" induction chemotherapy is feasible in high-risk AML and leads to higher CR rate compared to historical data without increase in toxicity rate, allowing more pts to receive allogeneic transplantation. Correlative laboratory studies are consistent with pre-clinical studies suggesting that this combination is associated with significant inhibition of SRC activity and enhanced activation of p53-target genes.
Dos Santos:Amgen: Employment. Stein:Amgen: Speakers Bureau. Chen:Seattle Genetics: Consultancy, Research Funding, Speakers Bureau; Millennium: Consultancy, Research Funding, Speakers Bureau; Merck: Consultancy, Research Funding; genentech: Consultancy, Speakers Bureau. Khaled:Sequenom: Research Funding.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Introduction
Efforts to improve the survival of non-Hodgkin lymphoma (NHL) patients with recurrent disease have focused primarily on the use of consolidative myeloablative autologous hematopoietic ...stem cell transplantation (HSCT). However, the major limitation of HSCT for NHL is the high incidence of relapse, even at maximally tolerated preparative regimen intensities. In a series of phase I studies designed to improve HSCT longterm remission rates, we have assessed the safety and feasibility of cellular immunotherapy utilizing ex vivo expanded autologous central memory (Tcm)-enrichedT cells that are genetically modified to express CD19-specific chimeric antigen receptors (CD19CAR), given in conjunction with standard of care myeloablative HSCT.
Methods
Here we present results from the first two studies investigating different starting cell populations and CAR constructs. The NHL1 trial utilized a starting population of CD8+ Tcm and transduced with a lentiviral vector encoding the 1st-generation CD19CAR (CD19R:zeta), consisting of a CD19-specific scFv linked to a CD3-zeta (CD19R:zeta) signaling domain. The NHL2 trial used a bulk Tcm population including both CD4+ and CD8+cells, which were transduced with lentiviral vectors encoding a 2nd-generation CD19CAR that added a CD28 costimulatory domain (CD19R:CD28:zeta) and a selectable marker for cell tracking (EGFRt). Engineered Tcm-derived CD19CAR T cells were infused 2 days after HSCT at dose levels of 25-200 x10^6 CAR T cells (dose levels in table), and all participants were followed for dose limiting toxicity (DLT) for 28 days. Both phase I studies utilized the target equivalence range design, which defines the dose escalation and de-escalation rules for determining maximum tolerated dose based on a target range of acceptable toxicity.
Results
NHL1 protocol (NCT01318317): Eight participants were consented and received CD8+ Tcm -derived CD19R:zeta T cell therapy. Seven patients had a diagnosis of diffuse large B cell lymphoma (DLBCL) and 1 had mantle cell lymphoma (MCL). Four of the 8 were female, and 3/8 were ≥ age 65 years. The mean age was 62 years (50-75). The median number of prior chemo/immunotherapy regimens was 3 (2-4). Two of the 8 (25%) participants had prior radiation. Five of 8 (63%) participants on NHL1 achieved a best response of CR or continuing CR. Four of 8 (50% 95% CI 16%, 84%) participants have progressed. The progression free survival (PFS) at both 1 and 2 years is 50%, 95% CI16%,84% with a median follow-up of 24.7 (min=24.0, max=26.7) months. There were 2 deaths, both from disease progression.
NHL2 protocol (NCT 01815749): Eight participants were consented and received Tcm-derived CD19R:CD28:zeta/EGFRt T cell therapy. Four patients had MCL, 4 had DLBCL, 3/8 were female, 2/8 were ≥ age 65 years. The mean age was 58 years (23-71). The median number of prior chemo/immunotherapy regimens was 2 (1-3). All eight NHL2 participants achieved a best response of CR or continuing CR. The PFS at 6 months is 100%, 95% CI63%, 100% with a median follow-up of 12.2 (min=10.0, max=14.1) months. To date 2 participants of the 8 (25%, 95% CI 3%, 65%) have progressed (one at 6.4 months and one at 12.6 months). There was 1 death from disease progression.
Both NHL1 and NHL2 trials demonstrated safety and feasibility. There were no DLTs, delayed hematopoietic reconstitution, or non-relapse mortality on either study. In NHL2, we employed bulk Tcm including both CD4+ and CD8+ cells in the CAR transduction and also added a CD28 co-stimulatory domain in the CAR design, to enhance persistence and antitumor activity. NHL2 exhibited better CAR T cell persistence compared to NHL1 T cell therapy based on area under the curve of log10copies/µg of genomic DNA from day 1 to 25 post infusion (mean difference = 14.8, 95% CI 7.4, 22.3, P<0.001) based on analysis of WPRE PCR data.
Conclusions
We conclude that Tcm-derived CD19CAR T cell therapy is very safe for treatment of poor-risk NHL patients undergoing autologous HSCT. We continue follow-up of these patients long-term to assess efficacy, and preliminary data are promising. Meanwhile we are exploring CAR vector design and T cell population modifications to improve the duration of anti-tumor immunity in the setting of immune reconstitution following engineered autograft.
TableTrialCAR+ Cell Dose# of PatientsNHL125 x 10^6150 x 10^64100 x 10^63NHL 250 x 10^63200 x 10^65
Khaled:Sequenom: Research Funding. Siddiqi:Pharmacyclics/Jannsen: Speakers Bureau; Kite pharma: Other: attended advisory board meeting; Seattle Genetics: Speakers Bureau. Riddell:Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Adaptive Biotechnologies: Consultancy; Cell Medica: Membership on an entity's Board of Directors or advisory committees. Jensen***:Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding. Forman***:Amgen: Consultancy; Mustang: Research Funding.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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