Haploidentical Natural Killer Research Articles

Haploidentical Natural Killer Cell Therapy as an Adjunct to Stem Cell Transplantation for Treatment of Refractory Acute Myeloid Leukemia.

Refractory acute myeloid leukemia (AML), defined as failure of two cycles of induction therapy at diagnosis or of one cycle at relapse, represents a subgroup with poor outcomes. Haploidentical natural killer cell (NK) therapy is a strategy that is being explored in refractory malignancies. Historically, at our center, patients with refractory AML have been treated with cytoreductive therapy (fludarabine + cytosine + granulocyte colony-stimulating factor ± idarubicin or mitoxantrone + etoposide) followed by 1-week rest and then reduced-intensity transplant with fludarabine + melphalan. We used the same backbone for this trial (CTRI/2019/02/017505) with the addition of CD56-positive cells from a family donor infused 1 day after the completion of chemotherapy. CD56-positive selection was done using a CliniMACS Prodigy system (Miltenyi Biotec, Bergisch Gladbach, Germany) followed by overnight incubation in autologous plasma with 2 micromolar arsenic trioxide and 500 U/mL of interleukin-2. From February 2019, 14 patients with a median age of 29 years (interquartile range [IQR]: 16.5-38.5) were enrolled in this trial. Six were females. Six had primary refractory AML while eight had relapsed refractory AML. The median CD56-cell dose infused was 46.16 × 106/kg (IQR: 25.06-70.36). One patient withdrew consent after NK cell infusion. Of the 13 patients who proceeded to transplant, five died of immediate post-transplant complications while two did not engraft but were in morphologic leukemia-free state (both subsequently died of infective complications after the second transplant). Of the remaining six patients who engrafted and survived beyond 1 month of the transplant, two developed disease relapse and died. The remaining four patients are alive and relapse free at the last follow-up (mean follow-up duration of surviving patients is 24 months). The 2-year estimated overall survival for the cohort was 28.6% ± 12.1% while the treatment-related mortality (TRM) with this approach was 38.5% ± 13.5%. Haploidentical NK cell therapy as an adjunct to transplant is safe and needs further exploration in patients with AML. For refractory AML, post-transplant NK infusion and strategies to reduce TRM while using pre-transplant NK infusion merit exploration.

284 - Haploidentical Natural Killer Cell Therapy As an Adjunct to Stem Cell Transplantation for Refractory Acute Myeloid Leukemia

284 - Haploidentical Natural Killer Cell Therapy As an Adjunct to Stem Cell Transplantation for Refractory Acute Myeloid Leukemia

Haploidentical Natural Killer Cell Therapy As an Adjunct to Stem Cell Transplantation for Refractory Acute Myeloid Leukemia

Refractory acute myeloid leukemia (AML), defined as failure of 2 cycles of induction therapy at diagnosis or of 1 cycle at relapse, represents a subgroup with poor clinical outcomes. In our transplant cohort, the 5-year overall survival in this subgroup was 16% (Ganapule at al. JGO 2017). Haploidentical natural killer cell (NK) therapy is a strategy that is being explored in refractory malignancies. Our in-vitro and animal model data suggest that exposure to arsenic trioxide (ATO) results in enhanced NK cytotoxicity (Alex AA et al. Front. Immunol 2018). Historically, at our center, patients with refractory AML have been treated with cytoreductive therapy (FLAG ± idarubicin or mitoxantrone + etoposide for 3 to 5 days) followed by 1-week rest and then a reduced-intensity transplant with fludarabine + melphalan conditioning while in peak cytopenia. From February 2019, we initiated a phase II single arm clinical trial (CTRI/2019/02/017505) enrolling patients with refractory AML planned for a stem cell transplant in peak cytopenia. Patients received CD56-positive cells from an HLA haploidentical related family donor (other than the stem cell donor, wherever feasible) following cytoreductive chemotherapy. The NK cell donor preference strategy included presence of KIR ligand mismatch, greater number of KIR B motifs (or the B score), lower donor age, and negative donor specific antibodies tested using flowcytometry crossmatch (Figure 1a). CD56-positive selection was done using CliniMACS prodigy system. This was followed by overnight incubation of the CD56 positive cells in autologous plasma with 2 micromolar ATO and 500 U/mL of interleukin-2. The CD56 positive cells were then infused to the patient 1-day after the completion of cytoreductive chemotherapy. This was followed by a reduced intensity stem cell transplant (Figure 1b). The primary outcome variable was 1-year relapse free survival. From February 2019, 14 patients with median age 28 years (IQR: 15.75-31.5) were enrolled in this trial. Six were females. Six had primary-refractory AML while 8 had relapsed-refractory AML. The cytoreductive chemotherapy was FLAG ± idarubicin (n=7), Mitoxantrone + Etoposide (n=6) and GCLAC (n=1). The median blast percentage on flowcytometry MRD testing prior to NK infusion was 15.9% (IQR: 9.1%-54.5%) (n=11). The median B score for the NK cell donors was 2 (IQR: 1-3). The median age of the NK cell donor was 43 years (IQR: 36-49.5). KIR ligand mismatch with the patient was noted in 2 donors. The median CD56-cell dose infused was 46.16 x 10 6/kg (IQR: 25.06-70.36) (Figure 1c). Pre-defined release criteria, including sterile cultures, and endotoxin negativity were met in all cases. There was no infusion related toxicity. The median blast percentage on flowcytometry MRD testing done following NK cell infusion was 11.9% (IQR: 4.9%-47.6%) (n=8). One patient withdrew consent after NK cell infusion and did not undergo transplant. For the remaining 13 patients, the stem cell donor was HLA matched (n=4), HLA 9/10 matched (n=1) or HLA haplomatched (n=8). The median CD34 cell dose infused was 10 x 10 6/kg (IQR:7.51-11.6). Five (38.5%) patients died of immediate post-transplant complications (sepsis (n=3) on days 1, 2 and 28, cerebral venous sinus thrombosis (n=1) on day 1 in a patient treated with hormonal contraceptives for menorrhagia, and veno-occlusive disease (n=1) on day 15 in a patient undergoing a second transplant) while 2 (15.4%) did not engraft (both subsequently died of infective complications following engraftment post-second transplant). Of the remaining 6 (46.2%) patients who engrafted and survived beyond 1 month of the transplant, the day 28 post-transplant MRD was negative for 5 patients while it was positive in 1 patient (0.13%). On follow up, 2 (15.4%) patients developed disease relapse (on days 54 and 218 respectively) and died. The remaining 4 (30.8%) patients are alive and relapse free at last follow up (mean follow up of surviving patients is 16 months). One patient received a CD34 cell boost on day 96 (cell dose - 8.55 x 10 6/kg) for poor graft function. For the entire cohort, the estimated 1-year event free survival is 28.8% ± 13.1%(Figure 1d). Whereas, acute GVHD was noted in 3 patients (50%; out of 6 evaluable patients) and chronic GVHD was noted in 3 patients (50%; out of the 6 evaluable patients). Thus, haploidentical NK cell therapy as an adjunct to transplant is safe and merits further evaluation in patients with AML. [Display omitted] DisclosuresMathews: Christian Medical College: Patents & Royalties: US 2020/0345770 A1 - Pub.Date Nov.5, 2020; AML: Other: Co-Inventor.

Effect of Recombinant Human Adenovirus Type 5 Injection Combined with Haploidentical Natural Killer Cell Immunotherapy on Immune Function and Adverse Reactions in Patients with Malignant Ascites Caused by Ovarian Cancer

Effect of Recombinant Human Adenovirus Type 5 Injection Combined with Haploidentical Natural Killer Cell Immunotherapy on Immune Function and Adverse Reactions in Patients with Malignant Ascites Caused by Ovarian Cancer

Cellular immunotherapy with multiple infusions of in vitro-expanded haploidentical natural killer cells after autologous transplantation for patients with plasma cell myeloma

Background aimsTo investigate the feasibility and safety of haploidentical natural killer (NK) cell infusions as consolidation immunotherapy after autologous stem cell transplant (ASCT) in patients with plasma cell myeloma. MethodsTen patients (median age, 59 years) received induction treatment followed by high-dose melphalan (200 mg/m2) at day –1, ASCT at day 0 and increasing NK cell doses (1.5 × 106, 1.5 × 107 and multiple doses of 1.0 × 108 cells/kg body weight) from day +1 to day +30 after ASCT. NK cells were harvested and purified from peripheral blood of haploidentical donors and expanded for 19 days with interleukin (IL)-2 and IL-15 under Good Manufacturing Practice conditions. ResultsNK cell numbers increased 56.0-fold (37.4- to 75.5-fold). Patients received a median of 3.8 × 108 (0.9–5.7 × 108) NK cells/kg body weight in six (three to eight) infusions. Multiparametric mass cytometry analysis demonstrated an altered surface receptor repertoire of expanded NK cells with increased degranulation and cytokine production activities but diminished expression of perforin. Donor NK cells were detectable in the peripheral blood, peaking 1 h after each dose (up to 90% donor NK cells). The treatment was safe and well tolerated, without evidence of graft-versus-host disease. Comparison with a control patient population receiving ASCT without NK cell infusions showed no significant difference in relapse, progression-free survival and overall survival. ConclusionsThis study demonstrates reliable manufacturing of high numbers of activated NK cells for multiple-dose infusions and safe administration of these cellular products. The trial was registered at ClinicalTrials.gov (identifier no. NCT01040026).

BMT CTN 1803: Trial to Investigate If Haploidentical Natural Killer Cells (CSTD002) Prevent Post-Transplant Relapse in AML and MDS (NK-REALM)

Background and Rationale Relapse remains the leading cause of treatment failure for 30–50% of patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic blood or marrow transplantation (BMT). Safety and relapse risk reduction with an ex vivo-expanded, donor-derived, haploidentical (haplo) natural killer (NK)-cell infusion in conjunction with haploBMT were reported by investigators at MD Anderson Cancer Center in a phase I study (Ciurea, Blood 2017). These data support investigation of CSTD002, haplo NK cells expanded ex vivo using plasma membrane nanoparticles bearing membrane-bound IL-21 and 4-1BBL. This study represents a public–private partnership between the sponsor (Kiadis Pharma) and the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), leveraging existing National Institutes of Health-supported clinical trials infrastructure to conduct the trial. Trial Design and Methods BMT CTN 1803 is a phase II, single-arm, open-label, multicenter trial designed to investigate the safety and efficacy of CSTD002 for the treatment of patients with high-risk AML or MDS undergoing haploBMT. An initial safety run-in phase will precede enrollment into the full study of approximately 60 patients. Donor peripheral blood will be drawn to start the NK-cell expansion approx. 5 weeks before the planned haploBMT. Patients will receive melphalan 140 mg/m2 IV (100 mg/m2 for patients ≥60 years old) on Day -7; fludarabine 40 mg/m2 IV on Days -7, -6, -5, and -4; and 2 Gy of total body irradiation on Day -3. Donor bone marrow will be harvested and given on Day 0. Three doses of CSTD002 will be administered IV on Days -2, +7, and +28, relative to the haploBMT. The recommended dose of CSTD002 for administration will be formulated at 1 × 108 NK cells/kg of recipient body weight. Graft-versus-host disease (GVHD) prophylaxis is post-transplantation cyclophosphamide with tacrolimus and mycophenolate mofetil. The primary endpoint is cumulative incidence of relapse at 1 year post haploBMT in patients receiving at least 1 infusion of CSTD002. Secondary endpoints are safety and tolerability of CSTD002; overall survival; non-relapse mortality; relapse-free survival; GVHD-free survival; cumulative incidence of acute GVHD and chronic GVHD; hematologic recovery; donor-cell engraftment; primary and secondary graft failure; overall incidence of toxicity; and cumulative incidence of infections including cytomegalovirus re-activation and symptomatic BK virus hemorrhagic cystitis. Exploratory endpoints are systemic immunosuppression-free survival; immune reconstitution at Days 28, 100, and 365 post haploBMT; proportion of patients with detectable minimal residual disease at Days 28 and 100 post haploBMT; feasibility of administering the planned CSTD002 doses; and impact of NK-cell alloreactivity on relapse and survival.

BMT CTN 1803: Haploidentical Natural Killer Cells (CSTD002) to Prevent Post-Transplant Relapse in AML and MDS (NK-REALM)

Background and Rationale: Relapse remains the leading cause of treatment failure for patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic blood or marrow transplantation (BMT). Although relapse rates vary based on patient population, age, and conditioning intensity, relapse is experienced in at least 30-50% after conventional BMT in high-risk AML/MDS. Initial safety and post-BMT relapse risk reduction results are reported by investigators at MD Anderson Cancer Center in a phase I study of ex vivo-expanded, donor-derived, haploidentical natural killer (NK)-cell infusion in conjunction with haploBMT. Of 13 patients with high-risk myeloid malignancies treated with NK cells, no infusion reactions or dose-limiting toxicities occurred and only 1 patient, treated at the lowest dose of 1×105 cells/kg, relapsed (Ciurea, Blood 2017). This experience supports investigation of CSTD002, a product derived from haploidentical donor NK cells and expanded ex vivo using plasma membrane (PM21) nanoparticles bearing membrane-bound IL-21 and 4-1BBL. This study represents a public-private partnership between the sponsor (Kiadis Pharma) and the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), leveraging existing National Institutes of Health-supported clinical trials infrastructure to conduct a complex cellular immunotherapy trial. We used contemporary, unpublished data from the Center for International Blood and Marrow Transplant Research registry to determine baseline relapse rates that informed the statistical design. Doses of NK cells expanded by a novel method and exceeding those previously achieved in most published studies will be given in the peri-transplant period to test the hypothesis that haploidentical NK cells can mediate an effective anti-leukemia response. Trial Design and Methods: BMT CTN 1803 is a phase II, single-arm, open-label, multicenter trial designed to investigate the safety and efficacy of CSTD002 for the treatment of patients with high-risk AML or MDS undergoing haploBMT. An initial safety run-in phase will precede enrollment into the full study of approximately 60 patients. Major inclusion criteria of patients and donors are listed in the Table. Peripheral blood will be drawn from the donor to start the NK-cell expansion approximately 5 weeks before the planned haploBMT. Patients will receive intravenous (IV) melphalan 140 mg/m2 (100 mg/m2 for patients ≥60 years old) on Day -7; fludarabine 40 mg/m2 IV on Days -7, -6, -5, and -4; and 2 Gy of total body irradiation on Day -3. Donor bone marrow will be harvested and given on Day 0. Three doses of CSTD002 will be administered IV on Days -2, +7, and +28, relative to the haploBMT. The recommended dose of CSTD002 for administration will be formulated at 1×108 NK cells/kg of recipient body weight. Graft-versus-host disease (GVHD) prophylaxis is post-transplantation cyclophosphamide with tacrolimus and mycophenolate mofetil. The primary endpoint is cumulative incidence of relapse at 1 year post haploBMT in patients receiving at least 1 infusion of CSTD002. Secondary endpoints are safety and tolerability of CSTD002; overall survival; non-relapse mortality; relapse-free survival; GVHD-free survival; cumulative incidence of acute GVHD and chronic GVHD; hematologic recovery; donor-cell engraftment; primary and secondary graft failure; overall incidence of toxicity; and cumulative incidence of infections including cytomegalovirus re-activation and symptomatic BK virus hemorrhagic cystitis. Exploratory endpoints are systemic immunosuppression-free survival; immune reconstitution at Days 28, 100, and 365 post haploBMT; proportion of patients with detectable minimal residual disease at Days 28 and 100 post haploBMT; feasibility of administering the planned CSTD002 doses; and impact of NK-cell alloreactivity on relapse and survival. Disclosures Vasu: Boehringer Ingelheim: Other: Travel support; Seattle Genetics: Other: Clinical trial support. Bejanyan:Kiadis Pharma: Other: advisory board. Devine:Kiadis Pharma: Other: Protocol development (via institution); Magenta Therapeutics: Other: Travel support for advisory board; My employer (National Marrow Donor Program) has equity interest in Magenta; Bristol Myers: Other: Grant for monitoring support & travel support. Krakow:Bellicum Pharmaceuticals: Research Funding; Highpass Bio: Research Funding; Magnolia Innovations: Other: Personal fees. Logan:Eisai: Other: Personal fees; Astellas: Other: Grant; Kiadis (formerly Cytosen): Other: Grant; Novartis: Other: Personal fees; Kite: Other: Grant. Luznik:Merck: Research Funding, Speakers Bureau; Genentech: Research Funding; AbbVie: Consultancy; WindMiL Therapeutics: Patents & Royalties: Patent holder. Barrett:Kiadis Pharma (formerly Cytosen): Other: Personal fees; Biologics Consulting Company: Other: Personal fees. Shan:Kiadis Pharma (formerly Cytosen): Employment. Champlin:Actinium: Consultancy; Johnson and Johnson: Consultancy; Sanofi-Genzyme: Research Funding.

First-in-human trial of rhIL-15 and haploidentical natural killer cell therapy for advanced acute myeloid leukemia

AbstractIn vivo expansion of haploidentical natural killer (NK) cell infusions with interleukin-2 (IL-2) can induce remission of refractory acute myeloid leukemia, but efficacy may be hampered by concurrent stimulation of host regulatory T cells. To overcome this limitation, we substituted the NK homeostatic factor IL-15 in 2 phase 1/2 trials. Forty-two patients received either intravenous (IV) (NCT01385423) or subcutaneous (SC) (NCT02395822) recombinant human IL-15 (rhIL-15) after lymphodepleting chemotherapy and haploidentical NK cells. Escalating doses of rhIL-15 (0.3-1.0 μg/kg) were given on 12 consecutive days in a phase 1 trial. Of 26 patients, 36% had robust in vivo NK-cell expansion at day 14, and 32% achieved complete remission. Hypothesizing that SC dosing of rhIL-15 would be safer and better tolerated, 16 patients received 10 once per day doses of SC rhIL-15 at 2.0 μg/kg on a phase 2 trial. NK-cell expansion at day 14 was seen in 27% of the patients, and 40% achieved remission. rhIL-15 induced better rates of in vivo NK-cell expansion and remission compared with previous trials with IL-2, but it was associated with previously unreported cytokine release syndrome (CRS) after SC but not IV dosing. CRS was observed in 56% of patients given SC rhIL-15 (with concurrent neurologic toxicity in 5 of 9 patients) and was responsive to steroids and tocilizumab. SC administration was associated with slower pharmacokinetic clearance and higher levels of IL-6 than IV dosing. These novel trials testing the use of IL-15 to potentiate cell therapy suggest that dosing schedules based on pharmacokinetics and pharmacodynamics will preserve the therapeutic benefits of IL-15 and minimize CRS. These trials were registered at www.clinicaltrials.gov as #NCT01385423 and #NCT02395822.

A phase II clinical trial of adoptive transfer of haploidentical natural killer cells for consolidation therapy of pediatric acute myeloid leukemia

Consolidation therapies for children with intermediate- or high-risk acute myeloid leukemia (AML) are urgently needed to achieve higher cure rates while limiting therapy-related toxicities. We determined if adoptive transfer of natural killer (NK) cells from haploidentical killer immunoglobulin–like receptor (KIR)–human leukocyte antigen (HLA)-mismatched donors may prolong event-free survival in children with intermediate-risk AML who were in first complete remission after chemotherapy. Patients received cyclophosphamide (Day − 7), fludarabine (Days − 6 through − 2), and subcutaneous interleukin-2 (Days − 1, 1, 3, 5, 7, and 9). Purified, unmanipulated NK cells were infused on Day 0, and NK cell chimerism and phenotyping from peripheral blood were performed on Days 7, 14, 21, and 28. As primary endpoint, the event-free survival was compared to a cohort of 55 patients who completed chemotherapy and were in first complete remission but did not receive NK cells. Donor NK cell kinetics were determined as secondary endpoints. Twenty-one patients (median age at diagnosis, 6.0 years [range, 0.1–15.3 years]) received a median of 12.5 × 106 NK cells/kg (range, 3.6–62.2 × 106 cells/kg) without major side effects. All but 3 demonstrated transient engraftment with donor NK cells (median peak donor chimerism, 4% [range, 0–43%]). KIR–HLA-mismatched NK cells expanded in 17 patients (81%) and contracted in 4 (19%). However, adoptive transfer of NK cells did not decrease the cumulative incidence of relapse (0.393 [95% confidence interval: 0.182–0.599] vs. 0.35 [0.209–0.495]; P = .556) and did not improve event-free (60.7 ± 10.9% vs. 69.1 ± 6.8%; P = .553) or overall survival (84.2 ± 8.5% vs. 79.1 ± 6.6%; P = .663) over chemotherapy alone. The lack of benefit may result from insufficient numbers and limited persistence of alloreactive donor NK cells but does not preclude its potential usefulness during other phases of therapy, or in combination with other immunotherapeutic agents.Trial registrationwww.clinicaltrials.gov, NCT00703820. Registered 24 June 2008.

Primed to Kill: CTV-1 Stimulated Haploidentical Natural Killer Cells for Consolidation of AML

Primed to Kill: CTV-1 Stimulated Haploidentical Natural Killer Cells for Consolidation of AML

Adoptive immunotherapy with haploidentical natural killer cells and Anti-GD2 monoclonal antibody m3F8 for resistant neuroblastoma: Results of a phase I study

ABSTRACTNatural killer (NK) cell-mediated antibody-dependent toxicity is a potent mechanism of action of the anti-GD2 murine monoclonal antibody 3F8 (m3F8). Killer immunoglobulin-like receptor (KIR) and HLA genotypes modulate NK activity and are key prognostic markers in m3F8-treated patients with neuroblastoma. Endogenous NK-cells are suppressed in the setting of high tumor burden and chemotherapy. Allogeneic NK-cells however, demonstrate potent anti-neuroblastoma activity. We report on the results of a phase I clinical trial of haploidentical NK-cells plus m3F8 administered to patients with high-risk neuroblastoma after conditioning chemotherapy. The primary objective was to determine the maximum tolerated NK-cell dose (MTD). Secondary objectives included assessing anti-neuroblastoma activity and its relationship to donor-recipient KIR/HLA genotypes, NK function, and donor NK chimerism. Patients received a lymphodepleting regimen prior to infusion of haploidentical CD3-CD56+ NK-cells, followed by m3F8. Overall and progression free survival (PFS) were assessed from the time of first NK-cell dose. Univariate Cox regression assessed relationship between dose and outcomes. Thirty-five patients received NK-cells at one of five dose levels ranging from <1×106 to 50×106 CD3-CD56+cells/kg. One patient experienced grade 3 hypertension and grade 4 pneumonitis. MTD was not reached. Ten patients (29%) had complete or partial response; 17 (47%) had no response; and eight (23%) had progressive disease. No relationship was found between response and KIR/HLA genotype or between response and FcγRIII receptor polymorphisms. Patients receiving >10×106 CD56+cells/kg had improved PFS (HR: 0.36, 95%CI: 0.15–0.87, p = 0.022). Patient NK-cells displayed high NKG2A expression, leading to inhibition by HLA-E-expressing neuroblastoma cells. Adoptive NK-cell therapy in combination with m3F8 is safe and has anti-neuroblastoma activity at higher cell doses.

Activated human primary NK cells efficiently kill colorectal cancer cells in 3D spheroid cultures irrespectively of the level of PD-L1 expression

ABSTRACT Haploidentical Natural Killer (NK) cells have been shown as an effective and safe alternative for the treatment of haematological malignancies with poor prognosis for which traditional therapies are ineffective. In contrast to haematological cancer cells, that mainly grow as single suspension cells, solid carcinomas are characterised by a tridimensional (3D) architecture that provide specific surviving advantages and resistance against chemo- and radiotherapy. However, little is known about the impact of 3D growth on solid cancer immunotherapy especially adoptive NK cell transfer. We have recently developed a protocol to activate ex vivo human primary NK cells using B lymphoblastic cell lines, which generates NK cells able to overcome chemoresistance in haematological cancer cells. Here we have analysed the activity of these allogeneic NK cells against colorectal (CRC) human cell lines growing in 3D spheroid culture and correlated with the expression of some of the main ligands regulating NK cell activity. Our results indicate that activated NK cells efficiently kill colorectal tumour cell spheroids in both 2D and 3D cultures. Notably, although 3D CRC cell cultures favoured the expression of the inhibitory immune checkpoint PD-L1, it did not correlate with increased resistance to NK cells. Finally, we have analysed in detail the infiltration of NK cells in 3D spheroids by microscopy and found that at low NK cell density, cell death is not observed although NK cells are able to infiltrate into the spheroid. In contrast, higher densities promote tumoural cell death before infiltration can be detected. These findings show that highly dense activated human primary NK cells efficiently kill colorectal carcinoma cells growing in 3D cultures independently of PD-L1 expression and suggest that the use of allogeneic activated NK cells could be beneficial for the treatment of colorectal carcinoma.

Recipient T Cell Exhaustion and Successful Adoptive Transfer of Haploidentical Natural Killer Cells

Natural killer (NK) cells mediate surveillance for malignancy. In some chemotherapy refractory myeloid leukemia patients, adoptive transfer of NK cells from haploidentical donors can induce remission. We have previously shown that remission induction is linked to NK cell persistence at day +14, but the factors influencing NK cell persistence are unknown. To address this question, patient samples from a phase I trial of National Cancer Institute (NCI) IL-15 in whom either did or did not show NK cell expansion were compared with healthy donor control subjects. Before lymphodepleting chemotherapy, high absolute CD3+ count was predictive of patients who failed to expand their haploidentical NK cell graft. Interestingly, both groups had elevated expression of inhibitory receptors and decreased cytokine production compared with control subjects, suggestive of T cell exhaustion among all patients before haploidentical NK cell infusion. At day +14, however, haploidentical NK cell expanders had persistence of recipient CD8+ T cells with the most exhausted inhibitory phenotype (either PD-1high or dual PD-1+Tim-3+) and elevated expression of T-bet and Eomes compared with NK cell nonexpanders and control subjects. This suggested that maintenance of an exhausted T cell state at day +14 permits haploidentical NK cell expansion and supports further efforts to selectively deplete recipient T cells or modulate their dysfunction.

Consolidation Therapy for Newly Diagnosed Pediatric Patients with High-Risk Neuroblastoma Using Busulfan/Melphalan, Autologous Hematopoietic Cell Transplantation, Anti-GD2 Antibody, Granulocyte-Macrophage Colony–Stimulating Factor, Interleukin-2, and Haploidentical Natural Killer Cells

The treatment of pediatric high-risk neuroblastoma is intensive and multimodal. Despite the introduction of immunotherapy for minimal residual disease, survival rates remain suboptimal and new therapies are needed. As part of a phase 2 trial, we are using a consolidation therapy regimen that combines a busulfan/melphalan conditioning schema, autologous hematopoietic cell transplantation (AHCT), and experimental immunotherapy with hu14.18K322A (a humanized anti-GD2 monoclonal antibody), granulocyte-macrophage colony–stimulating factor (GM-CSF), and IL-2, with or without the adoptive transfer of haploidentical natural killer cells (NKs). Here we report on 30 patients who have undergone AHCT with this experimental immunotherapy regimen, 21 of whom received haploidentical NKs. The median time to neutrophil engraftment was 13 days (range, 10 to 28 days) and to platelet engraftment of at least 20 × 103/mm3 was 36.5 days (range, 0 to 102 days); no clinical difference was seen in those who did or did not receive NKs. Eight patients developed veno-occlusive disease, with 3 having multiorgan dysfunction. Toxicities were similar for patients who did or did not receive NKs. We conclude that this consolidation regimen is feasible and has an acceptable acute toxicity profile.

92 - Haploidentical natural killer cell therapy: Analysis of 205 clinimacs procedures of CD3 depletion followed by CD56 selection

92 - Haploidentical natural killer cell therapy: Analysis of 205 clinimacs procedures of CD3 depletion followed by CD56 selection

Haploidentical Natural Killer Cell Infusion Induces Remission in Non-Hodgkin Lymphoma and Overcomes Resistance to Rituximab

Patients with chemotherapy refractory non-Hodgkin lymphoma (NHL) have poor prognosis. We report the results of a phase 2 clinical trial testing the efficacy of haploidentical donor NK cell infusion with rituximab for refractory NHL. Sixteen patients were enrolled, and 14 were evaluable.Treatment included IV lymphodepleting chemotherapy (pentostatin 3.75mg x 2 days; n=6 or fludarabine 25mg/m2 x 4 days; n=10) with cyclophosphamide (60mg/kg IV day -5; n=14). To enhance NK cell function and deplete regulatory T cells(Treg), we used the IL-2 receptor-targeting agent denileukin diftitox (18 μg/kg/day IV day -1; n=5) or methylprednisolone (1 mg/kg day -2 through day +9; n=9). Donor lymphocytes were CD3- and CD19-depleted and overnight stimulated with 1000 U/ml IL-2. The cellular product at a dose of 1.5-8 x 107 NK cells/kg was infused IV on day 0 followed by subcutaneous infusion of IL-2 at 9 million IU x 6 doses. Peripheral blood (PB) donor NK cells were evaluated by short tandem repeats and/or flow cytometry analyzing donor-specific HLA alleles.Patients characteristics included median age of 52 years (range 48-67); diffuse large B cell lymphoma was the most common diagnosis (n=11); all patients were rituximab and chemotherapy refractory.Of 14 evaluable patients at 2 months post-infusion, 4 achieved remissions (2 complete, 2 partial; 28%). Three patients in continuous remission proceeded to allogeneic donor transplantation at 2,3 and 9 months after NK cell therapy.Compared to healthy controls, NK cells in patients prior to therapy had reduced function (CD107a, INFγ and TNFα production), lower expression of natural cytotoxic receptors NKp46, NKp44 and DNAM (but higher NKp30) and reduced expression of suppressor receptors TIGIT, PD1 and TIM3.In all evaluable patients (n=9), donor NK cells persisted in the PB for at least 7 days after infusion with median 18% (range 0.5-97%) of the NK cells were of donor origin. In one responding patient, donor NK cells sustained beyond day 28. Responding patients (R) had significantly lower levels of absolute number of Treg (Foxp3+CD25+CD127-) at baselineand 14 days after therapy (Figure) as compared to non-responders (NR), however neither denileukin diftitox nor methylprednisolone resulted in PB Treg depletion. Expectedly, lower PB Tregs correlated with low serum levels of IL-10 (R2=0.7; p<0.001; n=12), suggestive of attenuated immuno-suppressive milieu. In addition, frequencies of PB myeloid derived suppressor cells (MDSC) were remarkably low in responders as compared to non-responders at baseline (4.5%±0.05% vs. 11%±6%) and after therapy (day 14: 3.8%±1%; vs. 9.4%±5%).Endogenous Inteleukin-15 (IL-15) serum levels peaked at the day of NK cell infusion (range 11-33pg/dl). Responders had higher IL-15 levels compared to non-responders at day 0 (Figure). IL-15 levels also correlated with functional NK cell killing at day 14 as measured by expression of CD107a (R2=0.8; p=0.008; n=5), suggesting that higher endogenous IL-15 improved NK cell cytotoxic capacity.We observed expected, but transient hematologic toxicity. Therapy was associated with grade 3 adverse effects (tumor lysis syndrome, Pneumocystis pneumonia; Clostridium difficile colitis, neutropenic fever; thrombotic microangiopathy). One unevaluable patient developed sepsis prior to NK cell infusion, and the second died of sepsis a week after therapy.In summary, our observation supports further investigation of donor NK cellular therapies for advanced NHL as a strategy to overcome chemoresistance. NK cell expansion and therapeutic efficacy might be further improved by administration of IL-15. [Display omitted] DisclosuresCooley:Fate Therapeutics: Research Funding. Miller:Oxis Biotech Scientific Advisory Board: Membership on an entity's Board of Directors or advisory committees.

Immunotherapy with natural killer cells: a possible approach for the treatment of Acute Myeloid Leukemia also in Brazil.

The allogeneic hematopoietic stem cell transplantation (HSCT) can cure intermediate and high-risk acute myeloid leukemia. Even with the development of strategies to reduce HSCT toxicity, this is still a complex treatment with high morbidity and mortality. Knowledge of the graft versus leukemia effect of HSCT has prepared the way for the development of Adoptive Immunotherapy or in vitro expansion of activated lymphocytes without alloreactivity, with subsequent intravenous infusion. The infusion of genetically modified T lymphocytes and haploidentical natural killer cells has been tested as an alternative to HSCT with very interesting results worldwide and in Brazil, as we not only have the technology of in vitro expansion of clinical grade lymphocytes available, but also do it according to the Good Manufacturing Practices that have been determined internationally.

Haploidentical Natural Killer Cells Infused before Allogeneic Stem Cell Transplantation for Myeloid Malignancies: A Phase I Trial

Allogeneic stem cell transplantation is an effective treatment for high-risk myeloid malignancies, but relapse remains the major post-transplantation cause of treatment failure. Alloreactive natural killer (NK) cells mediate a potent antileukemic effect and may also enhance engraftment and reduce graft-versus-host disease (GVHD). Haploidentical transplantations provide a setting in which NK cell alloreactivity can be manipulated, but they are associated with high rates of GVHD. We performed a phase I study infusing escalating doses of NK cells from an HLA haploidentical–related donor—selected for alloreactivity when possible—as a component of the preparative regimen for allotransplantation from a separate HLA-identical donor. The goal of infusing third-party alloreactive NK cells was to augment the antileukemic effect of the transplantation without worsening GVHD and, thus, improve the overall outcome of hematopoietic transplantation. Twenty-one patients with high-risk acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myelogenous leukemia refractory or beyond first remission received a preparative regimen with busulfan and fludarabine followed by infusion of apheresis-derived, antibody-selected, and IL-2–activated NK cells. Doses were initially based on total nucleated cell (TNC) content and later based on CD56+ cells to reduce variability. CD56+ content ranged from .02 to 8.32 × 106/kg. IL-2, .5 × 106 units/m2 subcutaneously was administered daily for 5 days in the final cohort (n = 10). CD3+ cells in the NK cell product were required to be < 105/kg. Median relapse-free, overall, and GVHD-free/relapse-free survival for all patients enrolled was 102, 233, and 89 days, respectively. Five patients are alive, 5 patients died of transplantation-related causes, and 11 patients died of relapse. Despite the small sample size, survival was highly associated with CD56+ cells delivered (P = .022) and development of ≥ grade 3 GVHD (P = .006). There were nonsignificant trends toward higher survival rates in those receiving NK cells from KIR ligand–mismatched donors and KIR-B haplotype donors. There was no association with disease type, remission at time of transplantation, or KIR content. GVHD was not associated with TNC, CD56+, or CD3+ cells infused in the NK cell product or the stem cell product. This trial demonstrates a lack of major toxicity attributable to third-party NK cell infusions delivered in combination with an HLA-compatible allogeneic transplantation. The infusion of haploidentical alloreactive NK cells was well tolerated and did not interfere with engraftment or increase the rate of GVHD after allogeneic hematopoietic transplantation. Durable complete remissions occurred in 5 patients at high risk for disease recurrence. This approach is being further developed in a phase I/II trial with ex vivo–expanded NK cells to increase the NK cell dose with the objective of reducing relapse and improving the outcome of allogeneic hematopoietic transplantation for AML/MDS.

Natural killer cell therapy in children with relapsed leukemia.

Novel therapies are needed for children with relapsed or refractory leukemia. We therefore tested the safety and feasibility of haploidentical natural killer cell therapy in this patient population. Twenty-nine children who had relapsed or refractory leukemia were treated with chemotherapy followed by the infusion of haploidentical NK cells. Cohort 1 included 14 children who had not undergone prior allogeneic hematopoietic cell transplantation (HCT), whereas Cohort 2 included 15 children with leukemia that had relapsed after HCT. Twenty-six (90%) NK donors were KIR mismatched (14 with one KIR and 12 with 2 KIRs). The peak NK chimerism levels were >10% donor in 87% of the evaluable recipients. In Cohort 1, 10 had responsive disease and 12 proceeded to HCT thereafter. Currently, 5 (36%) are alive without leukemia. In Cohort 2, 10 had responsive disease after NK therapy and successfully proceeded to second HCT. At present, 4 (27%) are alive and leukemia-free. The NK cell infusions and the IL-2 injections were well-tolerated. NK cell therapy is safe, feasible, and should be further investigated in patients with chemotherapy-resistant leukemia.

Different Aspects of Stem Cell Procedures in Children with Poor Responding Aml: When is HSCT the Best Answer?

Acute myeloid leukemia in children is a heterogeneous disease with different morphological and cytogenetic features. New diagnostic tools and treatments, improved supportive care and the use of genomic tissue typing in selecting donors for hematopoietic stem cell transplantation (HSCT) adds to increased survival rates. Candidates to HSCT in first complete remission are patients with cytogenetic or molecular unfavorable prognostic markers, or blasts &gt;15% after first induction. The use of minimal residual disease can also identify children benefiting from HSCT in first complete remission and the patients post HSCT with signs of relapse. The outcome and cure rate of acute myeloid leukemia, still remains poor and new diagnostic tools and treatments strategies need to be evaluated. In this management perspective, future management of novel minimal residual disease tools are discussed, conditioning therapies, as well as different transplantation procedures including haplo-transplantation and haplo-identical natural killer cell transplantation, but also altered graft-versus-host-disease treatments.