Nonclinical Investigation of Cytokine Mitigation Strategies for T-cell-Engaging Bispecifics in the Cynomolgus Macaque.

SUMMARY: T-cell-directed cancer therapies such as T-cell-engaging bispecifics (TCBs) are commonly associated with cytokine release syndrome and associated clinical signs that can limit their tolerability and therapeutic benefit. Strategies for reducing cytokine release are therefore needed. Here, we report on studies performed in cynomolgus monkeys to test different approaches for mitigating cytokine release with TCBs. A "priming dose" as well as subcutaneous dosing reduced cytokine release compared with intravenous dosing but did not affect the intended T-cell response to the bispecific. As another strategy, cytokines or cytokine responses were blocked with an anti-IL-6 antibody, dexamethasone, or a JAK1/TYK2-selective inhibitor, and the effects on toxicity as well as T-cell responses to a TCB were evaluated. The JAK1/TYK2 inhibitor and dexamethasone prevented CRS-associated clinical signs on the day of TCB administration, but the anti-IL-6 had little effect. All interventions allowed for functional T-cell responses and expected damage to target-bearing tissues, but the JAK1/TYK2 inhibitor prevented the upregulation of activation markers on T cells, suggesting the potential for suppression of T-cell responses. Our results suggest that short-term prophylactic dexamethasone treatment may be an effective option for blocking cytokine responses without affecting desired T-cell responses to TCBs.

Randomized Phase II Trial of Dendritic Cell/Myeloma Fusion Vaccine with Lenalidomide Maintenance after Upfront Autologous Hematopoietic Cell Transplantation for Multiple Myeloma: BMT CTN 1401.

PURPOSE: Vaccination with dendritic cell (DC)/multiple myeloma (MM) fusions has been shown to induce the expansion of circulating multiple myeloma-reactive lymphocytes and consolidation of clinical response following autologous hematopoietic cell transplant (auto-HCT). PATIENTS AND METHODS: In this randomized phase II trial (NCT02728102), we assessed the effect of DC/MM fusion vaccination, GM-CSF, and lenalidomide maintenance as compared with control arms of GM-CSF and lenalidomide or lenalidomide maintenance alone on clinical response rates and induction of multiple myeloma-specific immunity at 1-year posttransplant. RESULTS: The study enrolled 203 patients, with 140 randomized posttransplantation. Vaccine production was successful in 63 of 68 patients. At 1 year, rates of CR were 52.9% (vaccine) and 50% (control; P = 0.37, 80% CI 44.5%, 61.3%, and 41.6%, 58.4%, respectively), and rates of VGPR or better were 85.3% (vaccine) and 77.8% (control; P = 0.2). Conversion to CR at 1 year was 34.8% (vaccine) and 27.3% (control; P = 0.4). Vaccination induced a statistically significant expansion of multiple myeloma-reactive T cells at 1 year compared with before vaccination (P = 0.024) and in contrast to the nonvaccine arm (P = 0.026). Single-cell transcriptomics revealed clonotypic expansion of activated CD8 cells and shared dominant clonotypes between patients at 1-year posttransplant. CONCLUSIONS: DC/MM fusion vaccination with lenalidomide did not result in a statistically significant increase in CR rates at 1 year posttransplant but was associated with a significant increase in circulating multiple myeloma-reactive lymphocytes indicative of tumor-specific immunity. Site-specific production of a personalized cell therapy with centralized product characterization was effectively accomplished in the context of a multicenter cooperative group study. See related commentary by Qazilbash and Kwak, p. 4703.

Randomized Phase III BMT CTN Trial of Calcineurin Inhibitor-Free Chronic Graft-Versus-Host Disease Interventions in Myeloablative Hematopoietic Cell Transplantation for Hematologic Malignancies.

PURPOSE: Calcineurin inhibitors (CNI) are standard components of graft-versus-host disease (GVHD) prophylaxis after hematopoietic cell transplantation (HCT). Prior data suggested that CNI-free approaches using donor T-cell depletion, either by ex vivo CD34 selection or in vivo post-transplant cyclophosphamide (PTCy) as a single agent, are associated with lower rates of chronic GVHD (cGVHD). METHODS: This multicenter phase III trial randomly assigned patients with acute leukemia or myelodysplasia and an HLA-matched donor to receive CD34-selected peripheral blood stem cell, PTCy after a bone marrow (BM) graft, or tacrolimus and methotrexate after BM graft (control). The primary end point was cGVHD (moderate or severe) or relapse-free survival (CRFS). RESULTS: Among 346 patients enrolled, 327 received HCT, 300 per protocol. Intent-to-treat rates of 2-year CRFS were 50.6% for CD34 selection (hazard ratio [HR] compared with control, 0.80; 95% CI, 0.56 to 1.15; P = .24), 48.1% for PTCy (HR, 0.86; 0.61 to 1.23; P = .41), and 41.0% for control. Corresponding rates of overall survival were 60.1% (HR, 1.74; 1.09 to 2.80; P = .02), 76.2% (HR, 1.02; 0.60 to 1.72; P = .95), and 76.1%. CD34 selection was associated with lower moderate to severe cGVHD (HR, 0.25; 0.12 to 0.52; P = .02) but higher transplant-related mortality (HR, 2.76; 1.26 to 6.06; P = .01). PTCy was associated with comparable cGVHD and survival outcomes to control, and a trend toward lower disease relapse (HR, 0.52; 0.28 to 0.96; P = .037). CONCLUSION: CNI-free interventions as performed herein did not result in superior CRFS compared with tacrolimus and methotrexate with BM. Lower rates of moderate and severe cGVHD did not translate into improved survival.

Development of the first reference antibody panel for qualification and validation of cytokine release assay platforms - Report of an international collaborative study.

Immunomodulatory therapeutics such as monoclonal antibodies (mAb) carry an inherent risk of undesired immune reactions. One such risk is cytokine release syndrome (CRS), a rapid systemic inflammatory response characterized by the secretion of pro-inflammatory cytokines from immune cells. It is crucial for patient safety to correctly identify potential risk of CRS prior to first-in-human dose administration. For this purpose, a variety of in vitro cytokine release assays (CRA) are routinely used as part of the preclinical safety assessment of novel therapeutic mAbs. One of the challenges for the development and comparison of CRA performance is the lack of availability of standard positive and negative control mAbs for use in assay qualification. To address this issue, the National Institute for Biological Standards and Control (NIBSC) developed a reference panel of lyophilised mAbs known to induce CRS in the clinic: human anti-CD52, mouse anti-CD3 and human superagonistic (SA) anti-CD28 mAb manufactured according to the respective published sequences of Campath-1H® (alemtuzumab, IgG1) , Orthoclone OKT-3® (muromonab, IgG2a) and TGN1412 (theralizumab, IgG4), as well as three isotype matched negative controls (human IgG1, mouse IgG2a and human IgG4, respectively). The relative capacity of these control mAbs to stimulate the release of IFN-γ, IL-2, TNF-α and IL-6 in vitro was evaluated in eleven laboratories in an international collaborative study mediated through the HESI Immuno-safety Technical Committee Cytokine Release Assay Working Group. Participants tested the NIBSC mAbs in a variety of CRA platforms established at each institution. This paper presents the results from the centralised cytokine quantification on all the plasma/supernatants corresponding to the stimulation of immune cells in the different CRA platforms by a single concentration of each mAb. Each positive control mAb induced significant cytokine release in most of the tested CRA platforms. There was a high inter-laboratory variability in the levels of cytokines produced, but similar patterns of response were observed across laboratories that replicated the cytokine release patterns previously published for the respective clinical therapeutic mAbs. Therefore, the positive and negative mAbs are suitable as a reference panel for the qualification and validation of CRAs, comparison of different CRA platforms (e.g. solid vs aqueous phase), and intra- and inter-laboratory comparison of CRA performance. Thus, the use of this panel of positive and negative control mAbs will increase the confidence in the robustness of a CRA platform to identify a potential CRS risk for novel immunomodulatory therapeutic candidates.

Safety Profile of Good Manufacturing Practice Manufactured Interferon γ-Primed Mesenchymal Stem/Stromal Cells for Clinical Trials.

Mesenchymal stem/stromal cells (MSCs) are widely studied by both academia and industry for a broad array of clinical indications. The collective body of data provides compelling evidence of the clinical safety of MSC therapy. However, generally accepted proof of therapeutic efficacy has not yet been reported. In an effort to generate a more effective therapeutic cell product, investigators are focused on modifying MSC processing protocols to enhance the intrinsic biologic activity. Here, we report a Good Manufacturing Practice-compliant two-step MSC manufacturing protocol to generate MSCs or interferon γ (IFNγ) primed MSCs which allows freshly expanded cells to be infused in patients on a predetermined schedule. This protocol eliminates the need to infuse cryopreserved, just thawed cells which may reduce the immune modulatory activity. Moreover, using (IFNγ) as a prototypic cytokine, we demonstrate the feasibility of priming the cells with any biologic agent. We then characterized MSCs and IFNγ primed MSCs prepared with our protocol, by karyotype, in vitro potential for malignant transformation, biodistribution, effect on engraftment of transplanted hematopoietic cells, and in vivo toxicity in immune deficient mice including a complete post-mortem examination. We found no evidence of toxicity attributable to the MSC or IFNγ primed MSCs. Our data suggest that the clinical risk of infusing MSCs or IFNγ primed MSCs produced by our two-step protocol is not greater than MSCs currently in practice. While actual proof of safety requires phase I clinical trials, our data support the use of either cell product in new clinical studies. Stem Cells Translational Medicine 2017;6:1868-1879.

Granulocyte Colony-Stimulating Factor-Mobilized Allografts Contain Activated Immune Cell Subsets Associated with Risk of Acute and Chronic Graft-versus-Host Disease.

We defined associations among immune cell subsets in granulocyte colony-stimulating factor (G-CSF)-mobilized allografts and clinical outcomes after allogeneic hematopoietic cell transplantation (alloHCT). Fresh peripheral blood stem cell (PBSC) aliquots from 238 G-CSF-mobilized allografts were extensively characterized by immunophenotype. Subset-specific transplanted cells were correlated with acute graft-versus-host disease (aGVHD), chronic GVHD (cGVHD), malignant disease relapse, nonrelapse mortality, and overall survival. Of 238 assessable alloHCT recipients, 185 patients (78%) received reduced-intensity conditioning and 152 (64%) antithymocyte globulin-based serotherapy. Incidences of aGVHD and cGVHD were 58% and 48%, respectively. Median follow-up was 21 months (range, 1.4 to 41.1). In multivariable analyses adjusted for relevant clinical factors, allograft activated natural killer (NK) cells (CD56(+)CD16(+)CD69(+)CD158b(+)) were associated with a significantly lower risk of aGVHD (P = .0016; HR, .51; 95% confidence interval, .33 to .78), whereas late-activated HLA-DR(+) CD3(+) cells were associated with significantly higher aGVHD (P < .0005; HR, 2.31; 95% confidence interval, 1.55 to 3.43). In a subgroup of patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), receipt of an allograft from an older donor (≥40 years) was associated with a higher incidence of relapse (P = .0042; HR, 2.99); allograft content of early activated CD3(+) cells (CD3(+)CD69(+); P = .0024; HR, .4) and NKT cells (CD3(+)CD56(+); P = .0006; HR, .54) were associated with a lower incidence of relapse. Presence of HLA-Bw4-80Ile(+) genotype was associated with lower relapse incidence. In conclusion, activated NK cells within PBSC allografts associate with lower aGVHD risk, whereas HLA-DR(+) T cells associate with higher aGVHD and cGVHD risk. NKT cells and early activated T cells are associated with lower relapse risk in AML and MDS patients. These findings may have implications in therapeutic targeting of select populations in the allograft to minimize incidence of GVHD.

Atorvastatin for the Prophylaxis of Acute Graft-versus-Host Disease in Patients Undergoing HLA-Matched Related Donor Allogeneic Hematopoietic Stem Cell Transplantation (allo-HCT).

Statins possess potent immunomodulatory effects that may play a role in preventing acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). We performed a phase II study of atorvastatin for aGVHD prophylaxis when given to allo-HCT recipients and their HLA-matched sibling donors. Atorvastatin (40 mg/day) was administered to sibling donors, beginning 14 days before the anticipated start of stem cell collection. Allo-HCT recipients (n = 40) received atorvastatin (40 mg/day) in addition to standard aGVHD prophylaxis. The primary endpoint was cumulative incidence of grades II to IV aGVHD at day 100. Atorvastatin was well tolerated, with no attributable grades III to IV toxicities in donors or their recipients. Day 100 and 180 cumulative incidences of grades II to IV aGVHD were 30% (95% confidence interval [CI], 17% to 45%) and 40% (95% CI, 25% to 55%), respectively. One-year cumulative incidence of chronic GVHD was 43% (95% CI, 32% to 69%). One-year nonrelapse mortality and relapse incidences were 5.5% (95% CI, .9% to 16.5%) and 38% (95% CI, 18% to 47%), respectively. One-year progression-free and overall survival rates were 54% (95% CI, 38% to 71%) and 82% (95% CI, 69% to 94%). One-year GVHD-free, relapse-free survival was 27% (95% CI, 16% to 47%). These results did not differ from our historical control subjects (n = 96). Although safe and tolerable, the addition of atorvastatin did not appear to provide any benefit to standard GVHD prophylaxis alone.

The genomic sequence of lymphocryptovirus from cynomolgus macaque.

Lymphocryptoviruses such as Epstein-Barr virus (EBV) cause persistent infections in human and non-human primates, and suppression of the immune system can increase the risk of lymphocryptovirus (LCV)-associated tumor development in both human and non-human primates. To enable LCV infection as a non-clinical model to study effects of therapeutics on EBV immunity, we determined the genomic DNA sequence of the LCV from cynomolgus macaque, a species commonly used for non-clinical testing. Comparison to rhesus macaque LCV and human EBV sequences indicates that LCV from the cynomolgus macaque has the same genomic arrangement and a high degree of similarity in most genes, especially with rhesus macaque LCV. Genes showing lower similarity were those encoding proteins involved in latency and/or tumor promotion or immune evasion. The genomic sequence of LCV from cynomolgus macaque should aid the development of non-clinical tools for identifying therapeutics that impact LCV immunity and carry potential lymphoma risk.

Science, ethics and communication remain essential for the success of cell-based therapies.

Cell-based therapeutics, such as marrow or peripheral blood stem cell transplantation, are a standard of care for certain malignancies. More recently, a wider variety of cell-based therapeutics including the use of mesenchymal stromal/stem cells, T-cells, and others show great promise in a wider range of diseases. With increased efforts to expand cell-based treatments to several clinical settings, many institutions around the world have developed programs to explore cellular therapy's potential for safe and effective applications. In legitimate investigations, usually conducted through academic centers or biotechnology industry-sponsored efforts, these studies are regulated and peer-reviewed to ensure safety and clear determination of potential efficacy. However, in some cases, the use of cell-based approaches is conducted with insufficient preclinical data, scientific rationale, and/or study plan for the diseases claimed to be treated, with patients being charged for these services without clear evidence of clinical benefit. In this context, patients may not be properly informed regarding the exact treatment they are receiving within a consenting process that may not be completely valid or ethical. Here, the authors emphasize the importance of distinguishing "proven cell-based therapies" from "unproven" and unauthorized cell-based therapies. This publication also addresses the necessity for improved communication between the different stakeholders in the field, patient associations, and advocacy groups in particular, to favor medical innovation and provide legitimate benefits to patients. Considering the progressive growth of cell-based treatments, their increasing therapeutic value and the expectation that society has about these therapies, it is critically important to protect patients and ensure that the risk/benefit ratio is favorable. This paper is a review article. Literature referred to in this paper has been listed in the references section. The datasets supporting the conclusions of this article are available online by searching PubMed. Some original points in this article come from the laboratory practice in our research centers and the authors' experiences.

Measuring T-cell responses against LCV and CMV in cynomolgus macaques using ELISPOT: potential application to non-clinical testing of immunomodulatory therapeutics.

A number of immunomodulatory therapeutics increase the risk of disease associated with latent herpesviruses such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), a member of the lymphocryptovirus (LCV) family that infects humans. The diseases associated with loss of immunity to these viruses can have major impacts on patients as well as on the commercial viability of the immunomodulatory therapeutics. In an effort to develop non-clinical methods for measuring effects on anti-viral immunity, we have developed an interferon (IFN)-γ enzyme-linked immunosorbent spot (ELISPOT) assay to quantify the number of CMV or LCV-reactive T-cells in peripheral blood of cynomolgus macaques. After optimization of various parameters, the IFN-γ ELISPOT assay was characterized for specificity, intra-assay, monkey-to-monkey, and longitudinal variability and sensitivity to immunosuppression. The results show that nearly all animals have detectable responses against both CMV and LCV and responses were derived from T-cells specific to the virus of interest. Analyses of variability show assay reproducibility (≤23% CV), and that variability over time in anti-viral responses in individual animals (larger for LCV than for CMV) was ∼2-fold in most animals over a 3-month time period, which is predicted to allow for detection of drug-induced changes when using group sizes typical of non-clinical studies. In addition, the IFN-γ ELISPOT assay was capable of detecting decreases in the numbers of CMV and LCV reactive T-cells induced by immunosuppressive drugs in vitro. This assay may allow for non-clinical assessment of the effects of immunomodulatory therapeutics on anti-viral T-cell immunity in monkeys, and may help determine if therapeutics increase the risk of reactivating latent viral infections.

Effects of induction with novel agents versus conventional chemotherapy on mobilization and autologous stem cell transplant outcomes in multiple myeloma.

Multiple myeloma (MM) is the top indication for high-dose chemotherapy (HDC) with autologous stem cell transplantation (SCT), a strategy which improves progression-free survival and potentially overall survival (OS). Novel induction regimens incorporating the immunomodulatory (IMID) agents, such as thalidomide and lenalidomide and the proteosome inhibitor bortezomib improve response rates and survival for newly diagnosed patients. Recent data temper enthusiasm for these treatments by illustrating difficulty in some circumstances with mobilizing CD34(+) hematopoietic stem cells for subsequent HDC/SCT. We compare conventional induction regimens with novel agent-based induction strategies and the associated effects on stem cell mobilization and HDC/SCT outcome in 224 patients. Although patients exposed to novel agent inductions collected generally fewer CD34(+) cells than patients induced with chemotherapy, these differences did not translate into adverse consequences with subsequent HDC/SCT. We show that an improvement in OS after HDC/SCT may be related to induction therapy with novel agents as opposed to chemotherapy. Our data extrapolate on prior work and expand on ongoing controversies about optimal induction regimens for patients with MM planned for subsequent HDC/SCT and optimal sequencing of therapies.

Improved nonrelapse mortality and infection rate with lower dose of antithymocyte globulin in patients undergoing reduced-intensity conditioning allogeneic transplantation for hematologic malignancies.

We sought to reduce the risk of infectious complications and nonrelapse mortality (NRM) associated with the use of antithymocyte globulin (ATG) without compromising control of acute graft-versus-host disease (aGVHD) in patients undergoing reduced-intensity conditioning (RIC) transplantation. As part of an ongoing quality improvement effort, we lowered the dose of rabbit ATG from 7.5 mg/kg of ATG (R-ATG) (n = 39) to 6.0 mg/kg of ATG (r-ATG) (n = 33) in association with fludarabine (Flu) and busulfan (BU) RIC transplantation and then monitored patients for adverse events, relapse, and survival. Of the 72 mostly high risk (82%) patients studied, 89% received unrelated donor allografts, 25% of which were HLA-mismatched. No differences in posttransplantation full donor-cell chimerism rates were observed between the 2 ATG-dose groups (P > .05). When R-ATG versus r-ATG patients were compared, we observed no significant difference in the cumulative incidence of grade II-IV aGVHD (32% versus 27%; P = .73) or grade III-IV aGVHD (23% versus 11%; P = .28). However, the r-ATG group had significantly less cytomegalovirus (CMV) reactivation (64% versus 30%; P = .005) and bacterial infections (56% versus 18%; P = .001), a better 1-year cumulative incidence of NRM (18% versus 3%; P = .03), and a trend for better 1-year overall survival (OS) (64% versus 84%; P = .07) compared to R-ATG patients. A seemingly modest reduction in the dose of rabbit ATG did not compromise control of aGVHD or achievement of donor chimerism, but led to a significant decrease in the risk of serious infections and NRM in high-risk RIC allograft recipients.

Do clinical rehabilitation education programs really improve stroke-related knowledge?

OBJECTIVE: We evaluated the effectiveness of a clinical stroke education program for improving stroke-related health knowledge after inpatient rehabilitation in a "real world" setting. DESIGN: Thirty-four patients participated in an inpatient rehabilitation clinical stroke education program. Their stroke-related health knowledge in three key domains-risk factors, warning signs, and appropriate actions to take if a stroke is suspected-was evaluated at admission and 12 wks later using a single-group, pretest-posttest design. Pretest and posttest comparisons were conducted using the Marginal Homogeneity test and the McNemar test. RESULTS: Small, nonsignificant improvements in stroke-related health knowledge were detected at posttest. Twelve weeks after the education program, 29% of participants were unable to name a single risk factor, 32% were unable to name a single warning sign, and 29% were unable to name appropriate emergency action in the event they suspected a stroke. CONCLUSIONS: A substantial proportion of patients who completed our clinical stroke education program continued to have poor stroke-related health knowledge. We noted several limitations in our program that may have contributed to this outcome. Changes may be useful for improving the success of clinical stroke education programs, thereby reducing knowledge deficits.

Stroke-related knowledge and health behaviors among poststroke patients in inpatient rehabilitation.

OBJECTIVE: To measure stroke knowledge and prestroke personal health behaviors of stroke patients undergoing inpatient rehabilitation and their caregivers. DESIGN: Prospective cohort. SETTING: Academic rehabilitation hospital. PARTICIPANTS: A total of 130 stroke patients and 85 caregivers interviewed after ischemic stroke. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The Stroke Education Assessment measured stroke knowledge and prestroke personal health behaviors. RESULTS: Large deficiencies in patient and caregiver stroke knowledge were found. Fifty-two percent of patients could not name any stroke risk factors, 52% were unable to name a stroke warning sign, and 35% were unable to identify appropriate actions to take in a stroke emergency. Older patients were less knowledgeable than younger patients. Caregivers were more knowledgeable than patients. Regarding prestroke personal health behaviors, 28% of patients reported medication nonadherence, 26% did not see their primary care physician in the preceding year, and less than 40% of patients with diabetes or hypertension reported diets consistent with these diagnoses. CONCLUSIONS: Stroke patients participating in inpatient rehabilitation and their caregivers have large gaps in stroke knowledge and have suboptimal personal health behaviors, thereby putting patients at high risk for recurrent stroke. Our finding highlights the need to develop stroke-education programs for rehabilitating patients that are effective in closing these gaps in knowledge and personal health behaviors.