Safety and virologic impact of haploidentical NK cells plus IL-2 or N-803 in HIV infection

BACKGROUND

NK cells are dysfunctional in chronic HIV infection as they are not able to clear virus. We hypothesized that an infusion of NK cells, supported by IL-2 or IL-15, could decrease virus-producing cells in the lymphatic tissues.

METHODS

We conducted a phase 1 pilot study in 6 persons living with HIV (PLHIV), where a single infusion of haploidentical related donor NK cells was given plus either IL-2 or N-803 (an IL-15 superagonist).

RESULTS

The approach was well tolerated with no unexpected adverse events. We did not pre-treat recipients with cyclophosphamide or fludarabine to "make immunologic space", reasoning that PLHIV on stable antiretroviral treatment remain T-cell depleted in lymphatic tissues. We found donor cells remained detectable in blood for up to 8 days (like what is seen in cancer pretreatment with lymphodepleting chemotherapy) and in the lymph nodes and rectum up to 28 days. There was a moderate decrease in the frequency of viral RNA+ cells in lymph nodes.

CONCLUSION

There was a moderate decrease in HIV-producing cells in lymph nodes. Further studies are warranted to determine the impact of healthy NK cells on HIV reservoirs and if restoring NK-cell function could be part of an HIV cure strategy.

Impact of Integrase Strand Transfer Inhibitors on Cognition in the HAILO Cohort

BACKGROUND

Integrase inhibitors (INSTIs) have been associated with poorer cognition in people with HIV (PWH). We examined the impact of switching to INSTIs on neuropsychological (NP) outcomes in PWH 40 years of age and older.

METHODS

From the AIDS Clinical Trials Group observational cohort study, HAILO, we identified PWH who switched to INSTIs, had ≥2 NP assessments before and at least 1 after switch, and maintained viral suppression while on INSTIs. NP performance was assessed with a composite score (NPZ4) including Hopkins Verbal Learning Test (HVLT-R), Digit Symbol test (DSY), Trail Making A, and Trail Making B, while adjusting for covariates and learning effects. Outcomes changes from preswitch and postswitch periods were estimated using piecewise linear mixed models.

RESULTS

Among 395 PWH (mean age 54 years, 81% male, 20% Hispanic, and 29% Black) NPZ4 increased preswitch and postswitch. There was no difference in slopes between periods for NPZ4 [preswitch 0.036/year (95% CI: 0.03 to 0.043); postswitch 0.022/year (95% CI: 0.006 to 0.005); P = 0.147]. All tests scores improved preswitch (P < 0.01). Postswitch, Trail Making A and DSY increased (all P < 0.01) without differences in rate of change (all P > 0.05). HVLT-R had a nonsignificant decrease postswitch (P = 0.22), resulting in a significant preswitch vs postswitch difference in slopes (P = 0.03).

CONCLUSIONS

NP performance improved regardless of INSTI use. There was an attenuation of improvement in verbal memory in the postswitch vs preswitch period. The clinical significance of these changes is unclear but, overall, INSTIs did not have a consistent detrimental effect on NP outcomes.

Increased Peripheral Inflammation Is Associated With Structural Brain Changes and Reduced Blood Flow in People With Virologically Controlled HIV

BACKGROUND

While antiretroviral therapy (ART) has improved outcomes for people with HIV (PWH), brain dysfunction is still evident. Immune activation and inflammation remain elevated in PWH receiving ART, thereby contributing to morbidity and mortality. Previous studies demonstrated reduced functional and structural changes in PWH; however, underlying mechanisms remain elusive.

METHODS

Our cohort consisted of PWH with ART adherence and viral suppression ( < 50 copies/mL; N = 173). Measurements included immune cell markers of overall immune health (CD4/CD8 T-cell ratio) and myeloid inflammation (CD16+ monocytes), plasma markers of inflammatory status (soluble CD163 and CD14), and structural and functional neuroimaging (volume and cerebral blood flow [CBF], respectively).

RESULTS

Decreased CD4/CD8 ratios correlated with reduced brain volume, and higher levels of inflammatory CD16+ monocytes were associated with reduced brain volume in total cortex and gray matter. An increase in plasma soluble CD14-a marker of acute peripheral inflammation attributed to circulating microbial products-was associated with reduced CBF within the frontal, parietal, temporal, and occipital cortices and total gray matter.

CONCLUSIONS

CD4/CD8 ratio and number of CD16+ monocytes, which are chronic immune cell markers, are associated with volumetric loss in the brain. Additionally, this study shows a potential new association between plasma soluble CD14 and CBF.

Audit of Ireland's first manual vacuum aspiration service

INTRODUCTION

Manual vacuum aspiration (MVA) is a safe and effective alternative option for the management of first-trimester miscarriage, termination of pregnancy, or retained pregnancy tissue. Ireland's first MVA clinic was set up in the Rotunda Hospital in April 2020.

OBJECTIVE

To identify the number of women who have undergone MVA since establishing our service, to assess the efficacy and safety of MVA in that service, and to develop local Irish studies that further support the safety of MVA, adding to the international body of evidence.

METHODS

With the approval and assistance of the Clinical Audit Committee, we obtained a log of all patients who underwent MVA in the first 18 months of the service. We performed a retrospective electronic chart review using Maternal and Newborn Clinical Management System. We collected the data and preformed a descriptive analysis.

RESULTS

In total, 86 women underwent MVA, 85 (98.8%) of which were successfully completed. There were no immediate procedural complications, inter-hospital transfers, or emergency electric vacuum aspiration (EVA) required. We obtained an incomplete evacuation rate of 4.7% (n = 4).

CONCLUSION

We have demonstrated that the MVA service in the Rotunda Hospital is a safe, effective management option with advantages for both the patient and the healthcare system. We recommend consideration for provision of funding and resources to enable expansion of this service nationally in order to give women greater autonomy of choice in the management of early pregnancy complications and termination of pregnancy.

A chimeric antigen receptor uniquely recognizing MICA/B stress proteins provides an effective approach to target solid tumors

BACKGROUND

The advent of chimeric antigen receptor (CAR) T cell therapies has transformed the treatment of hematological malignancies; however, broader therapeutic success of CAR T cells has been limited in solid tumors because of their frequently heterogeneous composition. Stress proteins in the MICA and MICB (MICA/B) family are broadly expressed by tumor cells following DNA damage but are rapidly shed to evade immune detection.

METHODS

We have developed a novel CAR targeting the conserved α3 domain of MICA/B (3MICA/B CAR) and incorporated it into a multiplexed-engineered induced pluripotent stem cell (iPSC)-derived natural killer (NK) cell (3MICA/B CAR iNK) that expressed a shedding-resistant form of the CD16 Fc receptor to enable tumor recognition through two major targeting receptors.

FINDINGS

We demonstrated that 3MICA/B CAR mitigates MICA/B shedding and inhibition via soluble MICA/B while simultaneously exhibiting antigen-specific anti-tumor reactivity across an expansive library of human cancer cell lines. Pre-clinical assessment of 3MICA/B CAR iNK cells demonstrated potent antigen-specific in vivo cytolytic activity against both solid and hematological xenograft models, which was further enhanced in combination with tumor-targeted therapeutic antibodies that activate the CD16 Fc receptor.

CONCLUSIONS

Our work demonstrated 3MICA/B CAR iNK cells to be a promising multi-antigen-targeting cancer immunotherapy approach intended for solid tumors.

FUNDING

Funded by Fate Therapeutics and NIH (R01CA238039).

Exercise Training to Improve Brain Health in Older People Living With HIV: Study Protocol for a Randomized Controlled Trial

BACKGROUND

With the advent of antiretrovirals, people living with HIV are living near-normal lifespans. However, people living with HIV are at greater risk of experiencing cognitive impairment and reduced brain integrity despite well-controlled viremia. A robust literature supports exercise interventions as a method of improving cognition and structural brain integrity in older individuals without HIV. The effects of exercise on cardiometabolic, neurocognitive, and neural structures in middle-aged to older people living with HIV are less well known, with few prospective studies examining these measures.

OBJECTIVE

This prospective randomized clinical trial will examine the effects of a 6-month exercise training intervention compared to a 6-month stretching intervention (control) on cardiorespiratory fitness, physical function and strength, cognition, and neuroimaging measures of brain volumes and cerebral blood flow in people living with HIV.

METHODS

Sedentary middle-aged to older people living with HIV (ages≥40; n=150) with undetectable HIV viral load (<20 copies/mL) will be enrolled in the study. At the baseline and final visit, fasting plasma lipid, insulin, glucose, and brain neurotrophic factor concentrations; cardiorespiratory fitness; cognitive performance; brain volumes; and cerebral blood flow via a magnetic resonance imaging scan will be measured. Participants will be randomized in a 2:1 ratio to either the exercise or control stretching intervention. All participants will complete their assigned programs at a community fitness center 3 times a week for 6 months. A professional fitness trainer will provide personal training guidance at all sessions for individuals enrolled in both arms. Individuals randomized to the exercise intervention will perform endurance and strength training exercises, while those randomized to the control intervention will perform stretches to increase flexibility. A midpoint visit (at 3 months) will assess cognitive performance, and at the end point visit, subjects will undergo cardiorespiratory fitness and cognition testing, and a magnetic resonance imaging scan. Physical activity throughout the duration of the trial will be recorded using an actigraph.

RESULTS

Recruitment and data collection are complete as of December 2020. Data processing, cleaning, and organization are complete as of December 2021. Data analysis began in January 2022, with the publication of study results for primary aims 1 and 2 expected by early 2023.

CONCLUSIONS

This study will investigate the effects of a 6-month aerobic and resistance exercise training intervention to improve cardiometabolic risk factors, cognitive performance, cerebral structure, and blood flow in sedentary people living with HIV. Results will inform clinicians and patients of the potential benefits of a structured aerobic exercise training program on the cognitive, functional, and cardiometabolic health status of older people living with HIV. Assessment of compliance will inform the development and implementation of future exercise programs for people living with HIV.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02663934; https://clinicaltrials.gov/ct2/show/NCT02663934.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/41421.

The Structural and Functional Correlates of Frailty in Persons With Human Immunodeficiency Virus

BACKGROUND

Persons with HIV (PWH) are at increased risk of frailty, a clinically recognizable state of increased vulnerability resulting from aging-associated decline in multiple physiologic systems. Frailty is often defined by the Fried criteria, which includes subjective and objective standards concerning health resiliency. However, these frailty metrics do not incorporate cognitive performance or neuroimaging measures.

METHODS

We compared structural (diffusion tensor imaging [DTI]) and functional (cerebral blood flow [CBF]) neuroimaging markers in PWH with frailty and cognitive performance. Virologically controlled PWH were dichotomized as either frail (≥3) or nonfrail (<3) using the Fried criteria. Cognitive Z-scores, both domain (executive, psychomotor speed, language, and memory) and global, were derived from a battery of tests. We identified three regions of reduced CBF, based on a voxel-wise comparison of frail PWH compared with nonfrail PWH. These clusters (bilateral frontal and posterior cingulate) were subsequently used as seed regions of interest (ROIs) for DTI probabilistic white matter tractography.

RESULTS

White matter integrity connecting the ROIs was significantly decreased in frail compared with nonfrail PWH. No differences in cognition were observed between frail and nonfrail PWH. However, reductions in white matter integrity among these ROIs was significantly associated with worse psychomotor speed and executive function across the entire cohort.

CONCLUSIONS

We conclude that frailty in PWH can lead to structural and functional brain changes, including subtle changes that are not detectable by standard neuropsychological tests. Multimodal neuroimaging in conjunction with frailty assessment could identify pathological brain changes observed in PWH.

Machine Learning Quantifies Accelerated White-Matter Aging in Persons With HIV

BACKGROUND

Persons with HIV (PWH) undergo white matter changes, which can be quantified using the brain-age gap (BAG), the difference between chronological age and neuroimaging-based brain-predicted age. Accumulation of microstructural damage may be accelerated in PWH, especially with detectable viral load (VL).

METHODS

In total, 290 PWH (85% with undetectable VL) and 165 HIV-negative controls participated in neuroimaging and cognitive testing. BAG was measured using a Gaussian process regression model trained to predict age from diffusion magnetic resonance imaging in publicly available normative controls. To test for accelerated aging, BAG was modeled as an age × VL interaction. The relationship between BAG and global neuropsychological performance was examined. Other potential predictors of pathological aging were investigated in an exploratory analysis.

RESULTS

Age and detectable VL had a significant interactive effect: PWH with detectable VL accumulated +1.5 years BAG/decade versus HIV-negative controls (P = .018). PWH with undetectable VL accumulated +0.86 years BAG/decade, although this did not reach statistical significance (P = .052). BAG was associated with poorer global cognition only in PWH with detectable VL (P < .001). Exploratory analysis identified Framingham cardiovascular risk as an additional predictor of pathological aging (P = .027).

CONCLUSIONS

Aging with detectable HIV and cardiovascular disease may lead to white matter pathology and contribute to cognitive impairment.

Systemic IL-15 promotes allogeneic cell rejection in patients treated with natural killer cell adoptive therapy

Natural killer (NK) cells are a promising alternative to T cells for cancer immunotherapy. Adoptive therapies with allogeneic, cytokine-activated NK cells are being investigated in clinical trials. However, the optimal cytokine support after adoptive transfer to promote NK cell expansion, and persistence remains unclear. Correlative studies from 2 independent clinical trial cohorts treated with major histocompatibility complex-haploidentical NK cell therapy for relapsed/refractory acute myeloid leukemia revealed that cytokine support by systemic interleukin-15 (IL-15; N-803) resulted in reduced clinical activity, compared with IL-2. We hypothesized that the mechanism responsible was IL-15/N-803 promoting recipient CD8 T-cell activation that in turn accelerated donor NK cell rejection. This idea was supported by increased proliferating CD8+ T-cell numbers in patients treated with IL-15/N-803, compared with IL-2. Moreover, mixed lymphocyte reactions showed that IL-15/N-803 enhanced responder CD8 T-cell activation and proliferation, compared with IL-2 alone. Additionally, IL-15/N-803 accelerated the ability of responding T cells to kill stimulator-derived memory-like NK cells, demonstrating that additional IL-15 can hasten donor NK cell elimination. Thus, systemic IL-15 used to support allogeneic cell therapy may paradoxically limit their therapeutic window of opportunity and clinical activity. This study indicates that stimulating patient CD8 T-cell allo-rejection responses may critically limit allogeneic cellular therapy supported with IL-15. This trial was registered at www.clinicaltrials.gov as #NCT03050216 and #NCT01898793.

Accelerated Brain Aging and Cerebral Blood Flow Reduction in Persons With Human Immunodeficiency Virus

BACKGROUND

Persons with human immunodeficiency virus (PWH) are characterized by altered brain structure and function. As they attain normal lifespans, it has become crucial to understand potential interactions between human immunodeficiency virus (HIV) and aging. However, it remains unclear how brain aging varies with viral load (VL).

METHODS

In this study, we compare magnetic resonance imaging (MRI) biomarkers among PWH with undetectable VL (UVL; ≤50 genomic copies/mL; n = 230), PWH with detectable VL (DVL; >50 copies/mL; n = 93), and HIV-uninfected (HIV-) controls (n = 206). To quantify gray matter cerebral blood flow (CBF), we utilized arterial spin labeling. To measure structural aging, we used a publicly available deep learning algorithm to estimate brain age from T1-weighted MRI. Cognitive performance was measured using a neuropsychological battery covering 5 domains.

RESULTS

Associations between age and CBF varied with VL. Older PWH with DVL had reduced CBF vs PWH with UVL (P = .02). Structurally predicted brain aging was accelerated in PWH vs HIV- controls regardless of VL (P < .001). Overall, PWH had impaired learning, executive function, psychomotor speed, and language compared to HIV- controls. Structural brain aging was associated with reduced psychomotor speed (P < .001).

CONCLUSIONS

Brain aging in HIV is multifaceted. CBF depends on age and current VL and is improved by medication adherence. By contrast, structural aging is an indicator of cognitive function and reflects serostatus rather than current VL.

Womens experience of Manual Vacuum Aspiration: An Irish perspective

OBJECTIVE

Manual Vacuum Aspiration (MVA) is a well-established management option for early pregnancy loss or early termination of pregnancy. MVA is performed as out-patient surgical procedure using local anaesthetic whereby aspiration of uterine contents is achieved through use of a hand-held negative pressure syringe. Ireland's first MVA service was established at the Rotunda Hospital Dublin in April 2020,. The purpose of this study was to gather feedback from women who had undergone MVA in the unit.

STUDY DESIGN

Prospective mixed methods study of women attending for uterine aspiration under local anaesthetic from July to October 2020 in the unit. Consenting women were contacted one week following MVA via telephone. The survey conducted consisted of structured closed questions along with open-ended questions, to assess womens satisfaction in relation to all aspects of the MVA service.

RESULTS

Nineteen women took part in the study, a response rate of 86.4%. Participants reported feeling well informed prior to attending for MVA. Prior to the procedure, pain expectation scores were high but actual reported pain scores were much lower. Although some participants did find MVA uncomfortable, the fact the procedure was very quick and the side effects so minimal generally negated this. The location and set up of the clinic scored highly among participants as did the staff of the clinic. Overall satisfaction with the MVA service was high with 84.2% of participants reporting they would opt again for MVA in the future.

CONCLUSIONS

Women living in Ireland are interested and agreeable with having Manual Vacuum Aspiration as an available option for management of early pregnancy complications. Consideration should be given to expansion of MVA services nationally.

Following Transplantation for Acute Myelogenous Leukemia, Donor KIR Cen B02 Better Protects against Relapse than KIR Cen B01

In the treatment of acute myelogenous leukemia with allogeneic hematopoietic cell transplantation, we previously demonstrated that there is a greater protection from relapse of leukemia when the hematopoietic cell transplantation donor has either the Cen B/B KIR genotype or a genotype having two or more KIR B gene segments. In those earlier analyses, KIR genotyping could only be assessed at the low resolution of gene presence or absence. To give the analysis greater depth, we developed high-resolution KIR sequence-based typing that defines all the KIR alleles and distinguishes the expressed alleles from those that are not expressed. We now describe and analyze high-resolution KIR genotypes for 890 donors of this human transplant cohort. Cen B01 and Cen B02 are the common CenB haplotypes, with Cen B02 having evolved from Cen B01 by deletion of the KIR2DL5, 2DS3/5, 2DP1, and 2DL1 genes. We observed a consistent trend for Cen B02 to provide stronger protection against relapse than Cen B01 This correlation indicates that protection depends on the donor having inhibitory KIR2DL2 and/or activating KIR2DS2, and is enhanced by the donor lacking inhibitory KIR2DL1, 2DL3, and 3DL1. High-resolution KIR typing has allowed us to compare the strength of the interactions between the recipient's HLA class I and the KIR expressed by the donor-derived NK cells and T cells, but no clinically significant interactions were observed. The trend observed between donor Cen B02 and reduced relapse of leukemia points to the value of studying ever larger transplant cohorts.

Early Adaptive Natural Killer Cell Expansion Is Associated with Decreased Relapse After Autologous Transplantation for Multiple Myeloma

Adaptive natural killer (NK) cells are long-lived and exhibit properties of immunologic memory against cytomegalovirus (CMV). We previously reported that expansion of adaptive NK cells after CMV reactivation in recipients of allogeneic hematopoietic cell transplantation (HCT) was associated with a lower rate of relapse of acute myelogenous leukemia. In the present study, we examined the impact of adaptive NK cell expansion in a cohort of 110 individuals who underwent autologous HCT (AHCT) for a lymphoid malignancy (lymphoma or multiple myeloma [MM]). In this cohort, higher absolute numbers of adaptive NK cells (>1.58/μL) at day 28 post-AHCT were associated with significantly decreased risk of relapse in patients with MM. No significant association was seen in patients with lymphoma. Further stratification of MM patients by CMV serostatus found a strong protective effect of adaptive NK cells only in CMV-seropositive individuals. These findings suggest that strategies to increase adaptive NK cells after AHCT may be a therapeutic option in patients with MM.

Treatment of glioblastoma using multicomponent silica nanoparticles

Glioblastomas (GBMs) remain highly lethal. This partially stems from the presence of brain tumor initiating cells (BTICs), a highly plastic cellular subpopulation that is resistant to current therapies. In addition to resistance, the blood-brain barrier limits the penetration of most drugs into GBMs. To effectively deliver a BTIC-specific inhibitor to brain tumors, we developed a multicomponent nanoparticle, termed Fe@MSN, which contains a mesoporous silica shell and an iron oxide core. Fibronectin-targeting ligands directed the nanoparticle to the near-perivascular areas of GBM. After Fe@MSN particles deposited in the tumor, an external low-power radiofrequency (RF) field triggered rapid drug release due to mechanical tumbling of the particle resulting in penetration of high amounts of drug across the blood-brain tumor interface and widespread drug delivery into the GBM. We loaded the nanoparticle with the drug 1400W, which is a potent inhibitor of the inducible nitric oxide synthase (iNOS). It has been shown that iNOS is preferentially expressed in BTICs and is required for their maintenance. Using the 1400W-loaded Fe@MSN and RF-triggered release, in vivo studies indicated that the treatment disrupted the BTIC population in hypoxic niches, suppressed tumor growth and significantly increased survival in BTIC-derived GBM xenografts.

Abstract CT079: A Phase I study of PNK-007, allogeneic, off the shelf NK cell in relapsed/refractory AML (NCT02781467)

Background: PNK-007 is an allogeneic, off the shelf cell therapy enriched for CD56+/CD3- NK cells expanded from placental CD34+ cells. PNK-007 exhibits cytotoxicity against various cancer cell types, including acute myeloid leukemia (AML), and secretes cytokines during co-culture with cancer cells. Reported here are results of a Phase I first-in-man study in relapsed/refractory (r/r) AML patients (pts).

Methods: Placental CD34+ cells were cultivated in the presence of cytokines for 35 days to generate PNK-007 under the cGMP standards with release testing. HLA matching/KIR mismatching were not used. Eligible pts received a single PNK-007 infusion of 1, 3, or 10 million (M) cells/kg followed by rhIL-2 administered subcutaneously at 6M units every other day for up to 6 doses to facilitate PNK-007 expansion. Eligible pts with r/r AML received Lymphodepletion with Cy-Flu (60mg/kg Cy Days -5 to -4; 25mg/m2 Flu Days -6 to -2).

Results: Ten pts, age range 30-70 years (median 66), KPS &gt;70%, and WHO Classifications of recurrent genetic abnormalities (n=4), MDS-related changes (n=4), not otherwise specified (n=2), were treated with a single PNK-007 infusion followed by 5 to 6 rhIL-2 injections. These pts received 1 to 5 (median 3) prior lines of AML therapy and included 5 pts with a history of MDS and 5 pts received prior allogeneic SCT. Flow cytometric analysis of pt blood showed in vivo PNK-007 persistence, proliferation (Ki67) and maturation at dose levels 3M and 10M cells/kg between 7 to 28 days post-infusion. Functional analysis of PNK-007 isolated from 1 pt showed NK cell effector activity. One pt treated with 10M cells/kg PNK-007 developed Cytokine Release Syndrome (CRS) 14 days after infusion and was effectively managed with tocilizumab. This CRS event was deemed a dose-limiting toxicity. The other 9 pts did not experience CRS symptoms and PNK-007 was well tolerated with no infusion reactions or GvHD. No deaths were attributed to PNK-007. Efficacy was defined as complete remission rate (CR or CRp) at Day 42 and overall survival (OS) at 24 months. Although 2 of 8 efficacy evaluable patients had evidence of clinical benefit, Day 42 bone marrow biopsy could not be performed in either pt. On Day 21, a complete response with incomplete platelet recovery (CRp) was observed in the pt who experienced CRS. On Day 14, another patient treated at 10M cells/kg was observed to achieve MLFS. All pts died during the follow-up period of the study; 80% due to progressive AML and 20% due to AML-related complications. Median OS was 2.4 months.

Conclusion: PNK-007 is a fully allogeneic, off the shelf CD34+ derived NK cell product. A single infusion of PNK-007 up to 10M cells/kg with rhIL-2 following Cy-Flu conditioning was safe and well tolerated, with one treatable CRS event observed. Two of 10 pts treated achieved clinical response, assessed by the investigators as CRp and MLFS. Observed clinical data warrant further evaluation of PNK-007 treatment in AML.

Citation Format: Sarah Cooley, Parameswaran Hari, James McCloskey, Michael Byrne, Eunice Wang, Mohamad Hussein, Erica Giarritta, Xiaokui Zhang, Robert Hariri, Jeffrey S. Miller. A Phase I study of PNK-007, allogeneic, off the shelf NK cell in relapsed/refractory AML (NCT02781467) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT079.

Impact of Introduction of a Clinical Pathway for the Management of Pyelonephritis on Obstetric Patients: a Quality Improvement Project

Aim To determine whether the introduction of a clinical pathway for the treatment of pyelonephritis in obstetric patients would improve outcomes. Methods This was a retrospective study conducted in a maternity hospital using quantitative analysis methods. Patients who met laboratory and clinical criteria for pyelonephritis during data collection were included. Results The study included analysis of 23 patients pre-intervention and 19 post-intervention. Baseline and patient characteristics were similar for both groups. A statistically significant difference was seen in 3 of 7 outcome measures. Increased use of gentamicin (13% Vs 52% p=0.006), Increased number of renal ultrasounds (17% Vs 47%, p=0.04) and increased use of prophylaxis (21% Vs 68%, p=0.003). The proportion of patients receiving ≥ 10 days of IV antimicrobials decreased from 48% to 21% post-intervention (p=0.07). Discussion This study has shown that the introduction of a pathway for the treatment of pyelonephritis in pregnancy had a positive impact on several important clinical outcomes.

Adaptive NK cell reconstitution is associated with better clinical outcomes

BACKGROUND

Human cytomegalovirus (CMV) reactivation is a common occurrence early after transplant and is associated with heterogeneous NK cell subset expansion. These adaptive NK cell expansions are highly variable between recipients, with respect to magnitude and relative frequencies of adaptive NK cell subsets.

METHODS

To gain insight into the factors that influence adaptive NK cell expansion from a CMV naive graft source, we performed a high-resolution NK cell and CD8+ T cell phenotypic analysis of 215 patients with hematological malignancies that were transplanted with 2 partially HLA matched CMV negative umbilical cord blood units.

RESULTS

We found that adaptive NK cells were significantly higher in recipients who received nonmyeloablative conditioning (NMAC) relative to myeloablative conditioning (MAC), and high CMV neutralizing antibody titers correlated with the degree of adaptive NK cell expansion. The frequencies of adaptive NK cell subsets (defined by NKG2C, FcεRγ, EAT-2, and SYK expression) that reconstitute from donor hematopoietic progenitor cells largely matched the frequencies observed in the NK cell compartment of the recipient prior to conditioning, suggesting that host - as well as viral reactivation factors - may determine the phenotypic diversification after transplant. Additionally, multivariable analyses show that higher adaptive NK cell expansion associated with better disease-free survival.

CONCLUSIONS

Our findings provide important insights into adaptive NK cell reconstitution after transplant and support a role for adaptive NK cells in promoting better clinical outcomes.

FUNDING

The NIH and the National Marrow Donor Program.

KIR Donor Selection: Feasibility in Identifying better Donors

We previously reported that acute myelogenous leukemia (AML) transplants using killer cell immunoglobulin-type receptor (KIR) B haplotype better or best (≥2 B activating gene loci ± Cen B/B) unrelated donors (URDs) yield less relapse and better survival. In this prospective trial we evaluated 535 AML searches from 14 participating centers with centralized donor KIR genotyping for donor selection. This represented 3% to 48% of all AML searches (median 20%) per center, totaling 3 to 172 patients (median 22) per center. Donor KIR genotype was reported at a median of 14 days after request (≤26 days for 76% of searches). In 535 searches, 2080 donors were requested for KIR genotyping (mean 4.3 per search); and a median of 1.8 (range, 0 to 4.5) per search were KIR typed. Choosing more donors for confirmatory HLA and KIR haplotype identification enriched the likelihood of finding KIR better or best donors. The search process identified a mean of 30% KIR better or best donors; the success ranged from 24% to 38% in the 11 centers enrolling ≥8 patients. More donors requested for KIR genotyping increased the likelihood of identifying KIR better or best haplotype donors. Of the 247 transplants, 9.3% used KIR best, 19% used KIR better, and 48% used KIR neutral donors while 24% used a non-KIR-tested donor. KIR genotyping did not delay transplantation. The time from search to transplant was identical for transplants using a KIR-genotyped versus a non-KIR-genotyped donor. Prospective evaluation can rapidly identify KIR favorable genotype donors, but choosing more donors per search would substantially increase the likelihood of having a KIR best or better donor available for transplantation. Transplant centers and donor registries must both commit extra effort to incorporate new characteristics (beyond HLA, age, and parity) into improved donor selection. Deliberate efforts to present additional genetic factors for donor selection will require novel procedures.

Reduced-Intensity Conditioning Followed by Related and Unrelated Allografts for Hematologic Malignancies: Expanded Analysis and Long-Term Follow-Up

Reduced-intensity conditioning (RIC) extends the curative potential of allogeneic hematopoietic cell transplantation (HCT) to patients with hematologic malignancies unable to withstand myeloablative conditioning. We prospectively analyzed the outcomes of 292 consecutive patients, median age 58 years (range, 19 to 75) with hematologic malignancies treated with a uniform RIC regimen of cyclophosphamide, fludarabine, and total body irradiation (200 cGy) with or without antithymocyte globulin and cyclosporine and mycophenolate mofetil graft-versus-host disease (GVHD) prophylaxis followed by allogeneic HCT at the University of Minnesota from 2002 to 6. Probability of 5-year overall survival was 78% for patients with indolent non-Hodgkin lymphoma, 53% for chronic myelogenous leukemia, 55% for Hodgkin lymphoma, 40% for acute myelogenous leukemia, 37% for myelodysplastic syndrome, 29% for myeloma, and 14% for myeloproliferative neoplasms. Corresponding outcomes for relapse were 0%, 13%, 53%, 37%, 39%, 75%, and 29%, respectively. Disease risk index (DRI) predicted both survival and relapse with superior survival (64%) and lowest relapse (16%) in those with low risk score compared with 24% survival and 57% relapse in those with high/very-high risk scores. Recipient cytomegalovirus (CMV)-positive serostatus was protective from relapse with the lowest rates in those also receiving a CMV-positive donor graft (29%). The cumulative incidence of 2-year nonrelapse mortality was 26% and was lowest in those receiving a matched sibling graft at 21%, with low (21%) or intermediate (18%) HCT-specific comorbidity index, and was similar across age groups. The incidence of grades II to IV acute GVHD was 43% and grades III to IV 27%; the highest rates were found in those receiving an unrelated donor (URD) peripheral blood stem cell (PBSC) graft, at 50%. Chronic GVHD at 1 year was 36%. Future approaches incorporating alternative GVHD prophylaxis, particularly for URD PBSC grafts, and targeted post-transplant antineoplastic therapies for those with high DRI are indicated to improve these outcomes.

First-in-human phase 1 clinical study of the IL-15 superagonist complex ALT-803 to treat relapse after transplantation

New therapies for patients with hematologic malignancies who relapse after allogeneic hematopoietic cell transplantation (allo-HCT) are needed. Interleukin 15 (IL-15) is a cytokine that stimulates CD8+ T-cell and natural killer (NK) cell antitumor responses, and we hypothesized this cytokine may augment antileukemia/antilymphoma immunity in vivo. To test this, we performed a first-in-human multicenter phase 1 trial of the IL-15 superagonist complex ALT-803 in patients who relapsed >60 days after allo-HCT. ALT-803 was administered to 33 patients via the IV or subcutaneous (SQ) routes once weekly for 4 doses (dose levels of 1, 3, 6, and 10 μg/kg). ALT-803 was well tolerated, and no dose-limiting toxicities or treatment-emergent graft-versus-host disease requiring systemic therapy was observed in this clinical setting. Adverse events following IV administration included constitutional symptoms temporally related to increased serum IL-6 and interferon-γ. To mitigate these effects, the SQ route was tested. SQ delivery resulted in self-limited injection site rashes infiltrated with lymphocytes without acute constitutional symptoms. Pharmacokinetic analysis revealed prolonged (>96 hour) serum concentrations following SQ, but not IV, injection. ALT-803 stimulated the activation, proliferation, and expansion of NK cells and CD8+ T cells without increasing regulatory T cells. Responses were observed in 19% of evaluable patients, including 1 complete remission lasting 7 months. Thus, ALT-803 is a safe, well-tolerated agent that significantly increased NK and CD8+ T cell numbers and function. This immunostimulatory IL-15 superagonist warrants further investigation to augment antitumor immunity alone and combined with other immunotherapies. This trial was registered at www.clinicaltrials.gov as #NCT01885897.

Early Reconstitution of NK and γδ T Cells and Its Implication for the Design of Post-Transplant Immunotherapy

Relapse is the most frequent cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Natural killer (NK) cells and γδ T cells reconstitute early after allo-HSCT, contribute to tumor immunosurveillance via major histocompatibility complex-independent mechanisms and do not induce graft-versus-host disease. Here we performed a quantitative and qualitative analysis of the NK and γδ T cell repertoire in healthy individuals, recipients of HLA-matched sibling or unrelated donor allo-HSCT (MSD/MUD-HSCT) and umbilical cord blood-HSCT (UCB-HSCT). NK cells are present at high frequencies in all allo-HSCT recipients. Immune reconstitution (IR) of vδ2+ cells depended on stem cell source. In MSD/MUD-HSCT recipients, vδ2+ comprise up to 8% of the total lymphocyte pool, whereas vδ2+ T cells are barely detectable in UCB-HSCT recipients. Vδ1+ IR was driven by CMV reactivation and was comparable between MSD/MUD-HSCT and UCB-HSCT. Strategies to augment NK cell mediated tumor responses, similar to IL-15 and antibodies, also induced vδ2+ T cell responses against a variety of different tumor targets. Vδ1+ γδ T cells were induced less by these same stimuli. We also identified elevated expression of the checkpoint inhibitory molecule TIGIT (T cell Ig and ITIM domain), which is also observed on tumor-infiltrating lymphocytes and epidermal γδ T cells. Collectively, these data show multiple strategies that can result in a synergized NK and γδ T cell antitumor response. In the light of recent developments of low-toxicity allo-HSCT platforms, these interventions may contribute to the prevention of early relapse.

Combined OX40L and mTOR blockade controls effector T cell activation while preserving Treg reconstitution after transplant

A critical question facing the field of transplantation is how to control effector T cell (T_eff) activation while preserving regulatory T cell (T_reg) function. Standard calcineurin inhibitor-based strategies can partially control T_effs, but breakthrough activation still occurs, and these agents are antagonistic to T_reg function. Conversely, mechanistic target of rapamycin (mTOR) inhibition with sirolimus is more T_reg-compatible but is inadequate to fully control T_eff activation. In contrast, blockade of OX40L signaling has the capacity to partially control T_eff activation despite maintaining T_reg function. We used the nonhuman primate graft-versus-host disease (GVHD) model to probe the efficacy of combinatorial immunomodulation with sirolimus and the OX40L-blocking antibody KY1005. Our results demonstrate significant biologic activity of KY1005 alone (prolonging median GVHD-free survival from 8 to 19.5 days), as well as marked, synergistic control of GVHD with KY1005 + sirolimus (median survival time, >100 days; P < 0.01 compared to all other regimens), which was associated with potent control of both T_H/T_C1 (T helper cell 1/cytotoxic T cell 1) and T_H/T_C17 activation. Combined administration also maintained T_reg reconstitution [resulting in an enhanced T_reg/T_eff ratio (40% over baseline) in the KY1005/sirolimus cohort compared to a 2.9-fold decrease in the unprophylaxed GVHD cohort]. This unique immunologic signature resulted in transplant recipients that were able to control GVHD for the length of analysis and to down-regulate donor/recipient alloreactivity despite maintaining anti-third-party responses. These data indicate that combined OX40L blockade and sirolimus represents a promising strategy to induce immune balance after transplant and is an important candidate regimen for clinical translation.

Adaptive NK Cells Resist Regulatory T-cell Suppression Driven by IL37

Natural killer (NK) cells are capable of fighting viral infections and cancer. However, these responses are inhibited by immune suppressor cells in the tumor microenvironment. Tumor progression promotes the recruitment and generation of intratumoral regulatory T cells (Treg), associated with a poor prognosis in cancer patients. Here, we show that canonical NK cells are highly susceptible to Treg-mediated suppression, in contrast to highly resistant CD57⁺ FcεRγ^-NKG2C⁺ adaptive (CD56⁺CD3^-) NK cells that expand in cytomegalovirus exposed individuals. Specifically, Tregs suppressed canonical but not adaptive NK-cell proliferation, IFNγ production, degranulation, and cytotoxicity. Treg-mediated suppression was associated with canonical NK-cell downregulation of TIM3, a receptor that activates NK-cell IFNγ production upon ligand engagement, and upregulation of the NK-cell inhibitory receptors PD-1 and the IL1 receptor family member, IL1R8 (SIGIRR or TIR8). Treg production of the IL1R8 ligand, IL37, contributed to the phenotypic changes and diminished function in Treg-suppressed canonical NK cells. Blocking PD-1, IL1R8, or IL37 abrogated Treg suppression of canonical NK cells while maintaining NK-cell TIM3 expression. Our data uncover new mechanisms of Treg-mediated suppression of canonical NK cells and identify that adaptive NK cells are inherently resistant to Treg suppression. Strategies to enhance the frequency of adaptive NK cells in the tumor microenvironment or to blunt Treg suppression of canonical NK cells will enhance the efficacy of NK-cell cancer immunotherapy. Cancer Immunol Res; 6(7); 766-75. ©2018 AACR.

A Phase 1 Trial of CNDO-109-Activated Natural Killer Cells in Patients with High-Risk Acute Myeloid Leukemia

Natural killer (NK) cells are an emerging immunotherapy approach to acute myeloid leukemia (AML); however, the optimal approach to activate NK cells before adoptive transfer remains unclear. Human NK cells that are primed with the CTV-1 leukemia cell line lysate CNDO-109 exhibit enhanced cytotoxicity against NK cell-resistant cell lines. To translate this finding to the clinic, CNDO-109-activated NK cells (CNDO-109-NK cells) isolated from related HLA-haploidentical donors were evaluated in a phase 1 dose-escalation trial at doses of 3 × 10⁵ (n = 3), 1 × 10⁶ (n = 3), and 3 × 10⁶ (n = 6) cells/kg in patients with AML in first complete remission (CR1) at high risk for recurrence. Before CNDO-109-NK cell administration, patients were treated with lymphodepleting fludarabine/cyclophosphamide. CNDO-109-NK cells were well tolerated, and no dose-limiting toxicities were observed at the highest tested dose. The median relapse-free survival (RFS) by dose level was 105 (3 × 10⁵), 156 (1 × 10⁶), and 337 (3 × 10⁶) days. Two patients remained relapse-free in post-trial follow-up, with RFS durations exceeding 42.5 months. Donor NK cell microchimerism was detected on day 7 in 10 of 12 patients, with 3 patients having evidence of donor cells on day 14 or later. This trial establishes that CNDO-109-NK cells generated from related HLA haploidentical donors, cryopreserved, and then safely administered to AML patients with transient persistence without exogenous cytokine support. Three durable complete remissions of 32.6 to 47.6+ months were observed, suggesting additional clinical investigation of CNDO-109-NK cells for patients with myeloid malignancies, alone or in combination with additional immunotherapy strategies, is warranted.

Strategies to activate NK cells to prevent relapse and induce remission following hematopoietic stem cell transplantation

Natural killer (NK) cells are lymphocytes of innate immunity that respond to virus infected and tumor cells. After allogeneic transplantation, NK cells are the first reconstituting lymphocytes, but are dysfunctional. Manipulating this first wave of lymphocytes could be instrumental in reducing the 40% relapse rate following transplantation with reduced-intensity conditioning. NK cells express numerous activating and inhibitory receptors. Some recognize classical or nonclassical HLA class I ligands, others recognize class I-like ligands or unrelated ligands. Dominant in the NK-cell transplant literature are killer cell immunoglobulin-like receptors (KIRs), encoded on chromosome 19q. Inhibitory KIR recognition of the cognate HLA class I ligand is responsible for NK-cell education, which makes them tolerant of healthy cells, but responsive to unhealthy cells having reduced expression of HLA class I. KIR A and KIR B are functionally distinctive KIR haplotype groups that differ in KIR gene content. Allogeneic transplant donors having a KIR B haplotype and lacking a recipient HLA-C epitope provide protection against relapse from acute myeloid leukemia. Cytomegalovirus infection stimulates and expands a distinctive NK-cell population that expresses the NKG2C receptor and exhibits enhanced effector functions. These adaptive NK cells display immune memory and methylation signatures like CD8 T cells. As potential therapy, NK cells, including adaptive NK cells, can be adoptively transferred with, or without, agents such as interleukin-15 that promote NK-cell survival. Strategies combining NK-cell infusions with CD16-binding antibodies or immune engagers could make NK cells antigen specific. Together with checkpoint inhibitors, these approaches have considerable potential as anticancer therapies.

Haploidentical natural killer cells induce remissions in non-Hodgkin lymphoma patients with low levels of immune-suppressor cells

We report a novel phase 2 clinical trial in patients with poor prognosis refractory non-Hodgkin lymphoma (NHL) testing the efficacy of haploidentical donor natural killer (NK) cell therapy (NK dose 0.5-3.27 × 107 NK cells/kg) with rituximab and IL-2 (clinicaltrials.gov NCT01181258). Therapy was tolerated without graft-versus-host disease, cytokine release syndrome, or neurotoxicity. Of 14 evaluable patients, 4 had objective responses (29%; 95% CI 12-55%) at 2 months: 2 had complete response lasting 3 and 9 months. Circulating donor NK cells persisted for at least 7 days after infusion at the level 0.6-16 donor NK cells/µl or 0.35-90% of total CD56 cells. Responding patients had lower levels of circulating host-derived Tregs (17 ± 4 vs. 307 ± 152 cells/µL; p = 0.008) and myeloid-derived suppressor cells at baseline (6.6 ± 1.4% vs. 13.0 ± 2.7%; p = 0.06) than non-responding patients. Lower circulating Tregs correlated with low serum levels of IL-10 (R 2 = 0.64; p < 0.003; n = 11), suggestive of less immunosuppressive milieu. Low expression of PD-1 on recipient T cells before therapy was associated with response. Endogenous IL-15 levels were higher in responders than non-responding patients at the day of NK cell infusion (mean ± SEM: 30 ± 4; n = 4 vs. 19.0 ± 4.0 pg/ml; n = 8; p = 0.02) and correlated with day 14 NK cytotoxicity as measured by expression of CD107a (R 2 = 0.74; p = 0.0009; n = 12). In summary, our observations support development of donor NK cellular therapies for advanced NHL as a strategy to overcome chemoresistance. Therapeutic efficacy may be further improved through disruption of the immunosuppressive environment and infusion of exogenous IL-15.

GSK3 Inhibition Drives Maturation of NK Cells and Enhances Their Antitumor Activity

Maturation of human natural killer (NK) cells as defined by accumulation of cell-surface expression of CD57 is associated with increased cytotoxic character and TNF and IFNγ production upon target-cell recognition. Notably, multiple studies point to a unique role for CD57⁺ NK cells in cancer immunosurveillance, yet there is scant information about how they mature. In this study, we show that pharmacologic inhibition of GSK3 kinase in peripheral blood NK cells expanded ex vivo with IL15 greatly enhances CD57 upregulation and late-stage maturation. GSK3 inhibition elevated the expression of several transcription factors associated with late-stage NK-cell maturation including T-BET, ZEB2, and BLIMP-1 without affecting viability or proliferation. When exposed to human cancer cells, NK cell expanded ex vivo in the presence of a GSK3 inhibitor exhibited significantly higher production of TNF and IFNγ, elevated natural cytotoxicity, and increased antibody-dependent cellular cytotoxicity. In an established mouse xenograft model of ovarian cancer, adoptive transfer of NK cells conditioned in the same way also displayed more robust and durable tumor control. Our findings show how GSK3 kinase inhibition can greatly enhance the mature character of NK cells most desired for effective cancer immunotherapy. Cancer Res; 77(20); 5664-75. ©2017 AACR.

Abstract 3752: FATE-NK100: A novel NK cell-mediated cancer therapy

Natural killer (NK) cells are innate lymphoid cells that mediate immune responses against pathogens and cancer. Human NK cells are distinguished by the surface phenotype CD3-CD56+, and maturation of CD56dim NK cells is associated with acquisition of CD57. Rather than being an immunosenescence marker, CD57 acquisition represents a shift toward greater effector function, including increased CD16 signaling (Fc receptor responsible for triggering antibody-dependent cellular cytotoxicity), more potent cytotoxicity and enhanced inflammatory cytokine production after target cell engagement.

The main challenge in enriching for CD57+ NK cells using current ex vivo expansion protocols is that interleukin (IL)-15, the cytokine that drives NK cell proliferation and is critical for NK cell survival, preferentially expands less mature NK subsets that fail to terminally differentiate in culture. Our group has developed a novel NK cell expansion method that overcomes this barrier. Peripheral blood mononuclear cells from are depleted of CD3+ T cells and CD19+ B cells and cultured for 7 days with IL-15 and a small molecule inhibitor of glycogen synthase kinase 3-beta (GSK3β), a multifunctional kinase downstream of the PI(3)K pathway. Compared to vehicle control, addition of the GSK3β inhibitor led to a substantial increase (2.2-fold ± 0.19, n=23, p&lt;0.0001) in the CD57+ NK cell population, and total CD3-CD56+ NK cells were highly enriched (90.9% ± 2.2) relative to pre-culture CD3/CD19 depletion (23.3% ± 2.5) (p&lt;0.0001). We used a high-resolution imaging approach to analyze in vitro NK cell-mediated killing of the ovarian tumor cell line SKOV-3 and the lung carcinoma line A549. We demonstrate that NK cells from CD3/CD19-depleted peripheral blood products cultured for 7 days with the GSK3β inhibitor exhibit significantly more rapid killing kinetics and overall tumor killing relative to NK cells cultured for 7 days with IL-15 and the vehicle control. Superior tumor control of NK cells cultured with IL-15 and the GSK3β inhibitor was also observed against SKOV-3 tumor cells in a murine xenogeneic adoptive transfer model that included IL-2 injections.

We have scaled our process to manufacture a GMP product (referred to as FATE-NK100) for clinical use. Using an apheresis product from a donor containing 21.5 x 108 CD57+ NK cells, we achieved 6.4-fold NK cell expansion resulting in a final GMP-grade product containing 158 x 108 CD57+ NK cells. The cytotoxicity of these ex vivo expanded NK cells in response to SKOV-3 cells is superior to that of CD3/CD19-depleted haploidentical NK cells activated overnight with either IL-2 or IL-15 (representing the NK products used in current clinical trials). These data have been presented to the FDA in preparation for a clinical trial of FATE-NK100 in lymphodepleted patients with advanced AML anticipated for Q1 2017.

Citation Format: Frank Cichocki, Barham Valamehr, Ryan Bjordahl, Bin Zhang, Dhifaf Sarhan, Sarah Cooley, Bruce Blazar, Betsy Rezner, Paul Rogers, Chad Green, Stewart Abbot, Daniel Shoemaker, Scott Wolchko, Jeffrey S. Miller. FATE-NK100: A novel NK cell-mediated cancer therapy [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 3752. doi:10.1158/1538-7445.AM2017-3752

Abstract 3755: Renewable and genetically engineered natural killer cells for off-the-shelf adoptive cellular immunotherapy

The unique attributes of a combinatorial tumor recognition system, diminished off-tumor cytotoxicity, and multifaceted effector function make natural killer (NK) cells a prime candidate for a universal approach to cancer immunotherapy. In addition, NK cells are the principal mediator of antibody-directed cellular cytotoxicity (ADCC). However, NK cell function is often impaired in the setting of cancer, reducing the effectiveness of the endogenous immune system and the therapeutic efficacy of monoclonal antibodies. To address the need for advanced and combinatorial cancer therapies, we developed a unique and effective strategy to create a renewable source of engineered “off-the-shelf” NK cells with augmented function, including enhanced ADCC and persistence. Key challenges associated with genetic editing, limited expansion, persistence and variability of peripheral blood (PB)-derived NK cells were overcome by utilizing our induced pluripotent stem cell (iPSC) technology as the unlimited starting material for the reproducible and consistent derivation of engineered NK cells. Through targeted transgene integration, we produced a clonal iPSC master cell line to continuously produce NK cells engineered to uniformly express a high affinity, non-cleavable version of CD16 (hnCD16-NK). In directed differentiation, the hnCD16-NK cells displayed homogeneous expression of CD16 (&gt;95%) and a mature CD56+ NK cell phenotype, as exhibited by expression of KIR, NCRs, DNAM-1, and NKG2D. In contrast to endogenous CD16 expression, the engineered hnCD16 molecule was shown to be cleavage resistant upon NK cell activation (&gt;95% CD16+ hnCD16-NK vs. &lt;10% CD16+ PB-derived NK cell, upon target cell-mediated activation), and demonstrated enhanced antibody binding compared to PB-derived NK cells expressing the low-affinity variant. In addition to increased expression of the cytolytic molecules perforin and granzyme B and enhanced direct cytotoxicity against tumor targets, hnCD16-NK cells displayed superior ADCC capacity and cytokine production in response to CD16 stimulation. Importantly, manufacture of hnCD16-NK cells was proven to be highly scalable, delivering up to 107 fold expansion over a 35 day period. The maintained proliferative capacity can be in part associated with longer telomere length seen in hnCD16-NK cells. Furthermore, deletion of classical human leukocyte antigen molecules and ectopic expression of immunosuppressive proteins engineered at the iPSC level provided the ability of hnCD16-NK cells to potentially overcome the host histocompatibility barrier and to improve persistence in the allogeneic setting. In conclusion, the preclinical data presented herein highlight the therapeutic value of hnCD16-iNK cells as an ideal ADCC-mediated “off-the-shelf” NK cell-based immunotherapeutic product with augmented persistence, anti-tumor capacity, manufacturing reliability and preclinical efficacy.

Citation Format: Ryan Bjordahl, Frank Cichocki, Raedun Clarke, Svetlana Gaidarova, Brian Groff, Paul Rogers, Stacey Moreno, Ramzey Abujarour, Greg Bonello, Tom Lee, Weijie Lan, Matthieu Bauer, Dave Robbins, Betsy Rezner, Sarah Cooley, Bruce Walcheck, Stewart Abbot, Bruce Blazar, Scott Wolchko, Daniel Shoemaker, Jeffrey S. Miller, Bahram Valamehr. Renewable and genetically engineered natural killer cells for off-the-shelf adoptive cellular immunotherapy [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 3755. doi:10.1158/1538-7445.AM2017-3755

Regional age differences in gray matter diffusivity among healthy older adults

Aging is associated with microstructural changes in brain tissue that can be visualized using diffusion tensor imaging (DTI). While previous studies have established age-related changes in white matter (WM) diffusion using DTI, the impact of age on gray matter (GM) diffusion remains unclear. The present study utilized DTI metrics of mean diffusivity (MD) to identify age differences in GM/WM microstructure in a sample of healthy older adults (N = 60). A secondary aim was to determine the functional significance of whole-brain GM/WM MD on global cognitive function using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Participants were divided into three age brackets (ages 50-59, 60-69, and 70+) to examine differences in MD and cognition by decade. MD was examined bilaterally in the frontal, temporal, parietal, and occipital lobes for the primary analyses and an aggregate measure of whole-brain MD was used to test relationships with cognition. Significantly higher MD was observed in bilateral GM of the temporal and parietal lobes, and in right hemisphere WM of the frontal and temporal lobes of older individuals. The most robust differences in MD were between the 50-59 and 70+ age groups. Higher whole-brain GM MD was associated with poorer RBANS performance in the 60-69 age group. Results suggest that aging has a significant and differential impact on GM/WM diffusion in healthy older adults, which may explain a modest degree of cognitive variability at specific time points during older adulthood.

Recipient HLA-C Haplotypes and microRNA 148a/b Binding Sites Have No Impact on Allogeneic Hematopoietic Cell Transplantation Outcomes

Natural killer cells are important in graft-versus-leukemia responses after hematopoietic cell transplantation (HCT). A variety of surface receptors dictates natural killer cell function, including killer cell immunoglobulin-like receptor recognition of HLA-C. Previous single-center studies show that HLA-C epitopes, designated C1 and C2, were associated with allogeneic HCT outcomes; specifically, recipients homozygous for the C1 epitope (C1/C1) experienced a survival benefit. Additionally, mismatching at HLA-C was beneficial in recipients possessing at least 1 C2 allele, whereas the opposite was true for homozygous C1 (C1/C1) recipients where HLA-C mismatching resulted in worse outcomes. In this analysis we aimed to validate these findings in a large multicenter study. We also set out to determine whether surface expression of recipient HLA-C, determined by polymorphism in a microRNA (miR-148a/b) binding site within the 3'-region of the HLA-C transcript, was associated with transplant outcomes. In this large registry cohort, we were unable to confirm the prior findings regarding recipient HLA-C epitope status and outcome. Additionally, HLA-C surface expression (ie, surface density), as predicted by the miR-148a/b binding single nucleotide polymorphism, was also not with associated transplant outcomes. Collectively, neither HLA-C surface expression, as determined by miR-148a/b, nor recipient HLA-C epitopes (C1, C2) are associated with allogeneic HCT outcomes.

Transcriptome analysis of GVHD reveals aurora kinase A as a targetable pathway for disease prevention

Graft-versus-host disease (GVHD) is the most common complication of hematopoietic stem cell transplant (HCT). However, our understanding of the molecular pathways that cause this disease remains incomplete, leading to inadequate treatment strategies. To address this, we measured the gene expression profile of nonhuman primate (NHP) T cells during acute GVHD. Utilizing microarray technology, we measured the expression profiles of CD3(+) T cells from five cohorts: allogeneic transplant recipients receiving (i) no immunoprophylaxis (No Rx), (ii) sirolimus monotherapy (Siro), (iii) tacrolimus-methotrexate (Tac-Mtx), as well as (iv) autologous transplant recipients (Auto) and (v) healthy controls (HC). This comparison allowed us to identify transcriptomic signatures specific for alloreactive T cells and determine the impact of both mTOR (mechanistic target of rapamycin) and calcineurin inhibition on GVHD. We found that the transcriptional profile of unprophylaxed GVHD was characterized by significant perturbation of pathways regulating T cell proliferation, effector function, and cytokine synthesis. Within these pathways, we discovered potentially druggable targets not previously implicated in GVHD, prominently including aurora kinase A (AURKA). Utilizing a murine GVHD model, we demonstrated that pharmacologic inhibition of AURKA could improve survival. Moreover, we found enrichment of AURKA transcripts both in allo-proliferating T cells and in sorted T cells from patients with clinical GVHD. These data provide a comprehensive elucidation of the T cell transcriptome in primate acute GVHD and suggest that AURKA should be considered a target for preventing GVHD, which, given the many available AURKA inhibitors in clinical development, could be quickly deployed for the prevention of GVHD.

Adaptive NK Cells with Low TIGIT Expression Are Inherently Resistant to Myeloid-Derived Suppressor Cells

Human cytomegalovirus (CMV)-induced adaptive natural killer (NK) cells display distinct phenotypic and functional characteristics, including properties of immune memory. We hypothesized that these cells may be more resistant to suppression mediated by immunoregulatory cell subsets, making them attractive for use in cancer therapy. Here we report that relative to conventional NK cells, adaptive NK cells express lower levels of the inhibitory receptor T-cell Ig and ITIM domain (TIGIT), which results in resistance to immune suppression mediated by myeloid-derived suppressor cells (MDSC), as derived from cytokine induction in normal blood or patients with myelodysplastic syndrome. In contrast, conventional NK cells were potently suppressed by MDSCs, an effect abrogated completely by TIGIT blockade. Mechanistically, TIGIT signaling in NK cells after MDSC coculture led to a decrease in the phosphorylation of ZAP70/Syk and ERK1/2. These effects were reversed by blocking TIGIT on NK cells or by inhibiting production of reactive oxygen species (ROS) by MDSCs, the latter of which upregulated the TIGIT ligand CD155 on MDSCs. Accordingly, the blunted cytotoxicity of NK cells cocultured with MDSCs against tumor cells could be reversed by blocking TIGIT or ROS production. Overall, our results show how adaptive NK cells arising in response to CMV infection can escape MDSC-mediated suppression, and defined TIGIT antagonists as a novel type of checkpoint inhibitor to enhance NK-cell-mediated responses against cancer and infection. Cancer Res; 76(19); 5696-706. ©2016 AACR.

APPLICATION OF A NOVEL QUANTITATIVE TRACTOGRAPHY-BASED ANALYSIS OF DIFFUSION TENSOR IMAGING TO EXAMINE FIBER BUNDLE LENGTH IN HUMAN CEREBRAL WHITE MATTER

This paper reviews basic methods and recent applications of length-based fiber bundle analysis of cerebral white matter using diffusion magnetic resonance imaging (dMRI). Diffusion weighted imaging (DWI) is a dMRI technique that uses the random motion of water to probe tissue microstructure in the brain. Diffusion tensor imaging (DTI) is an extension of DWI that measures the magnitude and direction of water diffusion in cerebral white matter, using either voxel-based scalar metrics or tractography-based analyses. More recently, quantitative tractography based on diffusion tensor imaging (qtDTI) technology has been developed to help quantify aggregate structural anatomical properties of white matter fiber bundles, including both scalar metrics of bundle diffusion and more complex morphometric properties, such as fiber bundle length (FBL). Unlike traditional scalar diffusion metrics, FBL reflects the direction and curvature of white matter pathways coursing through the brain and is sensitive to changes within the entire tractography model. In this paper, we discuss applications of this approach to date that have provided new insights into brain organization and function. We also discuss opportunities for improving the methodology through more complex anatomical models and potential areas of new application for qtDTI.

Loss of T Follicular Helper Cells in the Peripheral Blood of Patients with Chronic Graft-versus-Host Disease

B cell antihost antibody production plays a central role in chronic graft-versus-host disease (cGVHD). T follicular helper (TFH) cells drive B cell responses and are implicated in this process. Given differences in cGVHD incidence between umbilical cord blood (UCB) and adult donor transplant recipients, we evaluated TFH cell reconstitution kinetics to define graft source differences and their potential pathogenic role in cGVHD. Although we observed significantly fewer TFH cells in the blood of UCB recipients (versus matched related donors [MRD]) early after transplantation, by 1 year the numbers of TFH cells were similar. Additionally, at both early (day 60) and late (1 year) time points, TFH cell phenotype was predominantly central memory cells in both cohorts. TFH cells were functional and able to produce multiple cytokines (INF-γ, TNF-α, IL-2, IL-17, and IL-21) after stimulation. In contrast to mouse models, where an enhanced frequency of splenic TFH cells contributes to cGVHD, patients with cGVHD showed significantly depleted circulating TFH cells after both UCB and MRD transplantation. Low numbers of TFH cells early after UCB transplantation could directly contribute to less cGVHD in this cohort. Additionally, systemic therapy (including steroids and calcineurin inhibitors) may contribute to decreases in TFH cells in patients with cGVHD. These data provide further evidence supporting the importance of TFH cells in cGVHD pathogenesis.