Donor-Derived Cytokine-Induced Killer Cell Infusion as Consolidation after Nonmyeloablative Allogeneic Transplantation for Myeloid Neoplasms.

Non-myeloablative conditioning, such as with total lymphoid irradiation and antithymocyte globulin (TLI-ATG), has allowed allogeneic hematopoietic cell transplantation (allo-HCT) with curative potential for older patients and those with comorbid medical conditions with myeloid neoplasms. However, early achievement of full donor chimerism (FDC) and relapse remain challenging. Cytokine-induced killer (CIK) cells have been shown to have antitumor cytotoxicity. Infusion of donor-derived CIK cells has been studied for hematologic malignancies relapsed after allo-HCT but has not been evaluated as post-transplant consolidation. In this phase II study, we prospectively studied whether a one-time infusion of 1 × 108/kg CD3+ donor-derived CIK cells administered between day +21 and day +35 after TLI-ATG conditioning could improve achievement of FDC by day +90 and 2-year clinical outcomes in patients with myeloid neoplasms. CIK cells, containing predominantly CD3+CD8+NKG2D+ cells along with significantly expanded CD3+CD56+ cells, were infused in 31 of 44 patients. Study outcomes were compared to outcomes of a retrospective historical cohort of 100 patients. We found that this one-time CIK infusion did not increase the rate of FDC by day +90. On an intention-to-treat analysis, 2-year non-relapse mortality (6.8%; 95% confidence interval [CI], 0-14.5%), event-free survival (27.3%; 95% CI, 16.8-44.2%), and overall survival (50.6%; 95% CI, 37.5-68.2%) were similar to the values seen in the historical cohort. The cumulative incidence of grade II-IV acute graft-versus-host disease at 1-year was 25.1% (95% CI, 12-38.2%). On univariate analysis, the presence of monosomal or complex karyotype was adversely associated with relapse-free survival and overall survival. Given the favorable safety profile of CIK cell infusion, strategies such as repeat dosing or genetic modification merit exploration. This trial was registered at ClinicalTrials.gov (NCT01392989).

Blinatumomab for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukemia.

Approximately 30% to 50% of adults with acute lymphoblastic leukemia (ALL) in hematologic complete remission after multiagent therapy exhibit minimal residual disease (MRD) by reverse transcriptase-polymerase chain reaction or flow cytometry. MRD is the strongest predictor of relapse in ALL. In this open-label, single-arm study, adults with B-cell precursor ALL in hematologic complete remission with MRD (≥10-3) received blinatumomab 15 µg/m2 per day by continuous IV infusion for up to 4 cycles. Patients could undergo allogeneic hematopoietic stem-cell transplantation any time after cycle 1. The primary end point was complete MRD response status after 1 cycle of blinatumomab. One hundred sixteen patients received blinatumomab. Eighty-eight (78%) of 113 evaluable patients achieved a complete MRD response. In the subgroup of 110 patients with Ph-negative ALL in hematologic remission, the Kaplan-Meier estimate of relapse-free survival (RFS) at 18 months was 54%. Median overall survival (OS) was 36.5 months. In landmark analyses, complete MRD responders had longer RFS (23.6 vs 5.7 months; P = .002) and OS (38.9 vs 12.5 months; P = .002) compared with MRD nonresponders. Adverse events were consistent with previous studies of blinatumomab. Twelve (10%) and 3 patients (3%) had grade 3 or 4 neurologic events, respectively. Four patients (3%) had cytokine release syndrome grade 1, n = 2; grade 3, n = 2), all during cycle 1. After treatment with blinatumomab in a population of patients with MRD-positive B-cell precursor ALL, a majority achieved a complete MRD response, which was associated with significantly longer RFS and OS compared with MRD nonresponders. This study is registered at www.clinicaltrials.gov as #NCT01207388.

The role of blinatumomab in patients with relapsed/refractory acute lymphoblastic leukemia.

Adults with relapsed/refractory B-acute lymphoblastic leukemia (ALL) have a complete remission (CR) rate of 20-45% and median overall survival of 3-9 months, depending on the duration of the first remission and number of lines of salvage therapy. Allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative option for adult patients with relapsed/refractory ALL, and achievement of CR is a crucial step before alloHSCT. Blinatumomab is a bispecific T-cell engager (BiTE®) antibody construct with dual specificity for CD19 and CD3, simultaneously binding CD3-positive cytotoxic T cells and CD19-positive B cells, resulting in T-cell-mediated serial lysis of normal and malignant B cells. It recently gained accelerated approval by the US Food and Drug Administration (FDA) for the treatment of relapsed/refractory Philadelphia chromosome-negative ALL, based on a large phase II trial of 189 adults with relapsed/refractory B-ALL, which showed a CR/CRh (CR with partial hematologic recovery) of 43% after two cycles of treatment. Toxicities include cytokine-release syndrome (CRS) and neurologic events (encephalopathy, aphasia, and seizure). CRS can be alleviated by step-up dosing and dexamethasone, without affecting the cytotoxic effect of blinatumomab. The cause of neurologic toxicity is unclear but is also observed with other T-cell therapies and may relate to variable expression of CD19 within the brain. This review encompasses the preclinical rationale of using the BITE® class of compounds (blinatumomab being the only one that is FDA approved), with clinical data using blinatumomab in the relapsed/refractory setting (pediatrics and adults), the minimal residual disease setting (adults), as well as Philadelphia chromosome-positive ALL. The review also examines the main adverse events: their prevention, recognition, and management; possible mechanisms of resistance; causes of relapse. It also summarizes future trials evaluating the drug earlier in the treatment course to improve activity.

Blinatumomab treatment of older adults with relapsed/refractory B-precursor acute lymphoblastic leukemia: Results from 2 phase 2 studies.

BACKGROUND: Older adults with relapsed/refractory B-precursor acute lymphoblastic leukemia (r/r ALL) are reported to have a poor prognosis and few therapeutic options. In the current study, the authors evaluated treatment with single-agent blinatumomab in adults aged ≥65 years with r/r ALL. METHODS: A total of 261 adults with r/r ALL who were examined across two phase 2 studies received blinatumomab in cycles of 4-week continuous infusion and 2-week treatment-free intervals. The primary endpoint in each study was complete remission (CR) or CR with partial hematologic recovery (CRh) during the first 2 cycles. Data were pooled and analyzed according to patient age at screening (aged ≥65 years vs aged <65 years). RESULTS: Of 36 older adults, 56% (95% confidence interval [95% CI], 38%-72%) achieved CR/CRh during the first 2 cycles compared with 46% (225 patients) (95% CI, 40%-53%) of younger adults. Complete minimal residual disease responses were 60% in older and 70% in younger responders. Three older responders (15%) and 61 younger responders (59%) proceeded to allogeneic hematopoietic stem cell transplantation. Kaplan-Meier curves overlapped for relapse-free and overall survival for both age groups. Older adults were found to have a similar incidence of grade ≥3 adverse events (AEs) as younger adults (86% vs 80%) but more grade ≥3 neurologic events (28% vs 13%). Cytokine release syndrome occurred in 7 older (19%) (1 case of grade 3) and 23 younger (10%) (4 cases of grade ≥3) adults. There were no treatment-related fatal AEs reported. CONCLUSIONS: Older adults with r/r ALL who were treated with single-agent blinatumomab were found to have similar hematologic response rates and incidence of grade ≥3 AEs compared with younger adults but had more neurologic events, which were reversible and primarily resolved with treatment interruption. Cancer 2016;122:2178-85. © 2016 American Cancer Society.

Prophylactic rituximab after allogeneic transplantation decreases B-cell alloimmunity with low chronic GVHD incidence.

B cells are involved in the pathogenesis of chronic GVHD (cGVHD). We hypothesized that prophylactic anti-B-cell therapy delivered 2 months after transplantation would decrease allogeneic donor B-cell immunity and possibly the incidence of cGVHD. Therefore, in the present study, patients with high-risk chronic lymphocytic leukemia (n = 22) and mantle-cell lymphoma (n = 13) received a total lymphoid irradiation of 80 cGy for 10 days and antithymocyte globulin 1.5 mg/kg/d for 5 days. Rituximab (375 mg/m(2)) was infused weekly on days 56, 63, 70, and 77 after transplantation. The incidence of acute GVHD was 6%. The cumulative incidence of cGVHD was 20%. Nonrelapse mortality was 3%. Rituximab treatment after allogeneic transplantation significantly reduced B-cell allogeneic immunity, with complete prevention of alloreactive H-Y Ab development in male patients with female donors (P = .01). Overall survival and freedom from progression at 4 years for chronic lymphocytic leukemia patients were 73% and 47%, respectively; for mantle-cell lymphoma patients, they were 69% and 53%, respectively.

Adoptive immunotherapy with cytokine-induced killer cells for patients with relapsed hematologic malignancies after allogeneic hematopoietic cell transplantation.

Donor leukocyte infusions induce remissions in some patients with hematologic malignancies who relapse after allogeneic hematopoietic cell transplantation (HCT); however, graft-versus-host disease (GVHD) remains the major complication of this strategy. Cytokine-induced killer (CIK) cells are a unique population of cytotoxic T lymphocytes that express the CD3(+)CD56(+) phenotype and show marked up-regulation of the natural killer cell receptor NKG2D (CD314). CIK cells are non-major histocompatibility complex-restricted and NKG2D-dependent in target recognition and cytotoxicity. We explored the feasibility of ex vivo expansion of allogeneic CIK cells in patients with relapsed hematologic malignancies after allogeneic HCT. Eighteen patients (median age, 53 years; range, 20-69 years) received CIK cell infusions at escalating doses of 1 × 10(7) CD3(+) cells/kg (n = 4), 5 × 10(7) CD3(+) cells/kg (n = 6), and 1 × 10(8) CD3(+) cells/kg (n = 8). The median expansion of CD3(+) cells was 12-fold (range, 4- to 91-fold). CD3(+)CD56(+) cells represented a median of 11% (range, 4%-44%) of the harvested cells, with a median 31-fold (range, 7- to 515-fold) expansion. Median CD3(+)CD314(+) cell expression was 53% (range, 32%-78%) of harvested cells. Significant cytotoxicity was demonstrated in vitro against a panel of human tumor cell lines. Acute GVHD grade I-II was seen in 2 patients, and 1 patient had limited chronic GVHD. After a median follow-up of 20 months (range, 1-69 months) from CIK infusion, the median overall survival was 28 months, and the median event-free survival was 4 months. All deaths were due to relapsed disease; however, 5 patients had longer remissions after infusion of CIK cells than from allogeneic HCT to relapse. Our findings indicate that this form of adoptive immunotherapy is well tolerated and induces a low incidence of GVHD, supporting further investigation as an upfront modality to enhance graft-versus-tumor responses in high-risk patient populations.

Biology and clinical effects of natural killer cells in allogeneic transplantation.

PURPOSE OF REVIEW: Following allogeneic hematopoietic cell transplantation, donor-derived natural killer (NK) cells target recipient hematopoietic cells, resulting in an antileukemia effect and a lower incidence of graft rejection. NK cells do not mediate and may diminish graft versus host disease. Here we review the determinants of NK cell alloreactivity and their implications for adoptive NK cell therapy. RECENT FINDINGS: NK cell alloreactivity has been defined by the absence of recipient MHC class I ligands for donor inhibitory killer immunoglobulin-like receptor (KIR) receptors, as predicted by a number of algorithms. Recently, the role of activating NK receptors and their cognate ligands has received more attention. The beneficial clinical effect of NK-cell alloreactivity has not been uniformly demonstrated, likely reflecting differences in conditioning regimens, graft components and posttransplant immune suppression. Investigations of NK cell phenotype and function after transplantation have helped demonstrate which NK cell subsets mediate the graft versus leukemia effect. These advances have proceeded in parallel with increasing facility in GMP-grade bulk purification and administration of NK cell preparations. SUMMARY: NK cells are a heterogeneous population of lymphocytes with diverse patterns of target-cell recognition and effector function. Further clinical and functional correlations will help maximize their potential for clinical benefit.