HA-1-targeted T cell receptor (TCR) T cell therapy for recurrent leukemia after hematopoietic stem cell transplantation

Relapse is the leading cause of death after allogeneic hematopoietic stem cell transplantation (HCT) for leukemia. T cells engineered by gene transfer to express T cell receptors (TCR; TCR-T) specific for hematopoietic-restricted minor histocompatibility (H) antigens may provide a potent selective anti-leukemic effect post-HCT. We conducted a phase I clinical trial employing a novel TCR-T product targeting the minor H antigen HA-1 to treat or consolidate treatment of persistent or recurrent leukemia and myeloid neoplasms. The primary objective was to evaluate the feasibility and safety of administration of HA-1 TCR-T post-HCT. CD8+ and CD4+ T cells expressing the HA-1 TCR and a CD8-co-receptor were successfully manufactured from HA-1 disparate HCT donors. One or more infusions of HA-1 TCR-T following lymphodepleting chemotherapy were administered to nine HCT recipients who had developed disease recurrence post-HCT. TCR-T cells expanded and persisted in vivo after adoptive transfer. No dose-limiting toxicities occurred. Although the study was not designed to assess efficacy, four patients achieved or maintained complete remissions following lymphodepletion and HA-1 TCR-T, with one ongoing at >2 years. Single-cell RNA sequencing of relapsing/progressive leukemia after TCR-T therapy identified upregulated molecules associated with T cell dysfunction or cancer cell survival. HA-1 TCR-T therapy appears feasible and safe and shows preliminary signals of efficacy. This clinical trial is registered at clinicaltrials.gov as NCT03326921.

Statistics, philosophy, and health: the SMAC 2021 webconference

SMAC 2021 was a webconference organized in June 2021. The aim of this conference was to bring together data scientists, (bio)statisticians, philosophers, and any person interested in the questions of causality and Bayesian statistics, ranging from technical to philosophical aspects. This webconference consisted of keynote speakers and contributed speakers, and closed with a round-table organized in an unusual fashion. Indeed, organisers asked world renowned scientists to prepare two videos: a short video presenting a question of interest to them and a longer one presenting their point of view on the question. The first video served as a "teaser" for the conference and the second were presented during the conference as an introduction to the round-table. These videos and this round-table generated original scientific insights and discussion worthy of being shared with the community which we do by means of this paper.

Trans-population graph-based coverage optimization of allogeneic cellular therapy

Background

Pre-clinical development and in-human trials of 'off-the-shelf' immune effector cell therapy (IECT) are burgeoning. IECT offers many potential advantages over autologous products. The relevant HLA matching criteria vary from product to product and depend on the strategies employed to reduce the risk of GvHD or to improve allo-IEC persistence, as warranted by different clinical indications, disease kinetics, on-target/off-tumor effects, and therapeutic cell type (T cell subtype, NK, etc.).

Objective

The optimal choice of candidate donors to maximize target patient population coverage and minimize cost and redundant effort in creating off-the-shelf IECT product banks is still an open problem. We propose here a solution to this problem, and test whether it would be more expensive to recruit additional donors or to prevent class I or class II HLA expression through gene editing.

Study design

We developed an optimal coverage problem, combined with a graph-based algorithm to solve the donor selection problem under different, clinically plausible scenarios (having different HLA matching priorities). We then compared the efficiency of different optimization algorithms - a greedy solution, a linear programming (LP) solution, and integer linear programming (ILP) -- as well as random donor selection (average of 5 random trials) to show that an optimization can be performed at the entire population level.

Results

The average additional population coverage per donor decrease with the number of donors, and varies with the scenario. The Greedy, LP and ILP algorithms consistently achieve the optimal coverage with far fewer donors than the random choice. In all cases, the number of randomly-selected donors required to achieve a desired coverage increases with increasing population. However, when optimal donors are selected, the number of donors required may counter-intuitively decrease with increasing population size. When comparing recruiting more donors vs gene editing, the latter was generally more expensive. When choosing donors and patients from different populations, the number of random donors required drastically increases, while the number of optimal donors does not change. Random donors fail to cover populations different from their original populations, while a small number of optimal donors from one population can cover a different population.

Discussion

Graph-based coverage optimization algorithms can flexibly handle various HLA matching criteria and accommodate additional information such as KIR genotype, when such information becomes routinely available. These algorithms offer a more efficient way to develop off-the-shelf IECT product banks compared to random donor selection and offer some possibility of improved transparency and standardization in product design.

Expert consensus on microtransplant for acute myeloid leukemia in elderly patients -report from the international microtransplant interest group

Recent studies have shown that microtransplant (MST) could improve outcome of patients with elderly acute myeloid leukemia (EAML). To further standardize the MST therapy and improve outcomes in EAML patients, based on analysis of the literature on MST, especially MST with EAML from January 1st, 2011 to November 30th, 2022, the International Microtransplant Interest Group provides recommendations and considerations for MST in the treatment of EAML. Four major issues related to MST for treating EAML were addressed: therapeutic principle of MST (1), candidates for MST (2), induction chemotherapy regimens (3), and post-remission therapy based on MST (4). Others included donor screening, infusion of donor cells, laboratory examinations, and complications of treatment.

Late Effects of Severe Acute Graft-versus-Host Disease on Quality of Life, Medical Comorbidities, and Survival

Grade III-IV acute graft-versus-host disease (aGVHD) is associated with high short-term morbidity and mortality following allogeneic hematopoietic cell transplantation (HCT). The long-term effects after recovery from grade III-IV aGVHD are unknown. This study aimed to analyze late medical comorbidities, quality of life, nonrelapse mortality, and survival in patients treated for grade III-IV aGVHD. Chart review identified late effects, and patients were asked to complete annual surveys to collect patient-reported outcomes. Outcomes were compared between patients with grade 0-I aGVHD and grade III-IV aGVHD who underwent HCT between 2001 and 2019 and survived for at least 1 year post-transplantation. Patients with a history of grade III-IV aGVHD (n = 192) had significantly higher rates of late medical comorbidities (P < .001) and worse physical (P = .01) and mental (P = .04) functioning compared with patients with grade 0-I aGVHD (n = 615). Patients who survived for >1 year post-transplantation and had prior grade III-IV aGVHD also had worse 5-year overall survival (77.5% versus 83.6%; P = .006) and higher nonrelapse mortality (19.2% versus 10.6%; P < .001) compared with those with a history of grade 0-I aGVHD. No between-group difference was found in cumulative incidence of chronic GVHD. Patients who recover from severe aGVHD remain vulnerable to developing late comorbidities. These patients would likely benefit from continued monitoring and supportive care in an attempt to prevent late effects and improve survival.

Humoral and Cellular Immune Response to Covid-19 Vaccination in Patients with Chronic Graft-versus-Host Disease on Immunosuppression

Chronic graft-versus-host disease (cGVHD) and its management with immunosuppressive therapies increase the susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, as well as progression to severe Coronavirus 19 disease (COVID-19). Vaccination against COVID-19 is strongly recommended, but efficacy data are limited in this patient population. In this study, responses to COVID-19 vaccination were measured at 3 time points—after the initial vaccine series, before the third dose, and after the third dose—in adults with cGVHD receiving immunosuppressive therapy. Humoral response was measured by quantitative anti-spike antibody and neutralizing antibody levels. Anti-nucleocapsid antibody levels were measured to detect natural infection. T cell response was evaluated by a novel immunosequencing technique combined with immune repertoire profiling from cryopreserved peripheral blood mononuclear cell samples. Present or absent T cell responses were determined by the relative proportion of unique SARS-CoV-2-associated T cell receptor sequences (“breadth”) plus clonal expansion of the response (“depth”) compared with those in a reference population. Based on both neutralizing antibody and T cell responses, patients were categorized as vaccine responders (both detected), nonresponders (neither detected), or mixed (one but not both detected). Thirty-two patients were enrolled for the initial series, including 17 (53%) positive responders, 7 (22%) mixed responders, and 8 (25%) nonresponders. All but one patient categorized as mixed responders had humoral responses while lacking T cell responses. No statistical differences were observed in patient characteristics among the 3 groups of patients categorized by immune response, although sample sizes were limited. Significant positive correlations were observed between the robustness of cellular and humoral responses after the initial series. Among the 20 patients with paired samples (pre- and post-third dose), a third vaccination resulted in increased neutralizing antibody titers. cGVHD worsened in 10 patients (26%; 6 after the initial series and 4 after the third dose), necessitating escalation of immunosuppressive doses in 5 patients, although 4 had been tapering immunosuppression and 5 had already worsening cGVHD at the time of vaccination, and a clear association between COVID-19 vaccination and cGVHD could not be drawn. Among the patients with cGVHD on immunosuppressive therapy, 72% demonstrated a neutralizing antibody response after a 2-dose primary COVID-19 vaccination, two-thirds of whom also developed a T cell response; 25% had neither a humoral nor a T cell response. A third dose further amplified the antibody response.

Neuropathy and Muscle Cramps in Autologous and Allogeneic Hematopoietic Cell Transplantation Survivors

Although autologous and allogeneic hematopoietic cell transplantation are used to treat hematologic diseases, they are associated with high morbidity and mortality. The goal of this cross-sectional study was to describe the incidence, characteristics, severity and clinical correlates of neuropathy and muscle cramps, as self-reported by hematopoietic cell transplantation survivors. We included all respondents to a survey conducted July 1, 2020, to June 30, 2021. Surveys were completed online or on-paper according to participants' preferences; they received one reminder if no survey was received 1 month after distribution. Statistics are primarily descriptive comparing subgroups of patients. Of 4641 potentially eligible patients, 1745 responded and are included in the analysis. Participants (615 [35%] autologous, 1130 [65%] allogeneic) were a median age of 64.1 years (interquartile range [IQR] 55.2-70.8) and surveyed at a median of 11 years (IQR 4-21) after their most recent transplantation. Neuropathy symptoms were reported by 65% of autologous recipients, 66% of allogeneic transplant recipients with current chronic graft versus host disease (GVHD), and 45% of allogeneic recipients who never developed chronic GVHD. Muscle cramps were reported by 56% of autologous recipients, and 52% of allogeneic recipients and were rated as "very painful" by nearly half of patients who experienced them. These results suggest that neuropathy symptoms and muscle cramps are much more prevalent among survivors after hematopoietic cell transplantation than previously recognized. Better approaches for prevention and treatment of these bothersome complications are needed.

Naive T-Cell Depletion to Prevent Chronic Graft-Versus-Host Disease

PURPOSE

Graft-versus-host disease (GVHD) causes morbidity and mortality following allogeneic hematopoietic cell transplantation. Naive T cells (TN) cause severe GVHD in murine models. We evaluated chronic GVHD (cGVHD) and other outcomes in three phase II clinical trials of TN-depletion of peripheral blood stem-cell (PBSC) grafts.

METHODS

One hundred thirty-eight patients with acute leukemia received TN-depleted PBSC from HLA-matched related or unrelated donors following conditioning with high- or intermediate-dose total-body irradiation and chemotherapy. GVHD prophylaxis was with tacrolimus, with or without methotrexate or mycophenolate mofetil. Subjects received CD34-selected PBSC and a defined dose of memory T cells depleted of TN. Median follow-up was 4 years. The primary outcome of the analysis of cumulative data from the three trials was cGVHD.

RESULTS

cGVHD was very infrequent and mild (3-year cumulative incidence total, 7% [95% CI, 2 to 11]; moderate, 1% [95% CI, 0 to 2]; severe, 0%). Grade III and IV acute GVHD (aGVHD) occurred in 4% (95% CI, 1 to 8) and 0%, respectively. The cumulative incidence of grade II aGVHD, which was mostly stage 1 upper gastrointestinal GVHD, was 71% (95% CI, 64 to 79). Recipients of matched related donor and matched unrelated donor grafts had similar rates of grade III aGVHD (5% [95% CI, 0 to 9] and 4% [95% CI, 0 to 9]) and cGVHD (7% [95% CI, 2 to 13] and 6% [95% CI, 0 to 12]). Overall survival, cGVHD-free, relapse-free survival, relapse, and nonrelapse mortality were, respectively, 77% (95% CI, 71 to 85), 68% (95% CI, 61 to 76), 23% (95% CI, 16 to 30), and 8% (95% CI, 3 to 13) at 3 years.

CONCLUSION

Depletion of TN from PBSC allografts results in very low incidences of severe acute and any cGVHD, without apparent excess risks of relapse or nonrelapse mortality, distinguishing this novel graft engineering strategy from other hematopoietic cell transplantation approaches.

Precision medicine: Statistical methods for estimating adaptive treatment strategies

SERIES EDITORS' NOTE

The beauty of science is that all the important things are unpredictable. Freeman Dyson In the typescript which follows, Moodie and Krakow tackle the topical issue of precision medicine and statistical methods for estimating adaptive treatment strategies. This may be the most difficult typescript in our series so far for non-statisticians to understand. It even has equations! But please bear with the authors and give it a chance. One needs not to understand the equations to get the thrust of the strategy.Precision medicine as we discuss elsewhere, is misnamed. In statistics and mathematics precision refers to getting the same answer again and again. It does not mean getting the correct answer, the term for which is accuracy, not precision. However, precision is the current buzz word so there's no point trying to get this straight. When we think about precision we need to consider two elements, reproducibility and replicability. Reproducibility means you give me your data and computer code and I come to the same conclusion you did. Replicability is another matter. I try to replicate your experiment and hopefully reach the same conclusion. In medicine, replicability is obviously more important than reproducibility but things which cannot be reproduced are unlikely to be replicated.As the authors discuss, one can think about precision medicine as one does a family vacation. A best vacation depends on several co-variates: where you live, your prior travel experiences, advice from family and friends, online reviews, Wikitravel, cost, your travel budget, if you have kids and many other co-variates. Consequently, there is unlikely to be a best vacation for everyone. Yours might be a week at the Ritz Carlton Cancun with dinner at Careyes and ours, a week at the Pfister Hotel in Milwaukee with dinner at Mader's German Restaurant (bring simvastatin). Similarly, it is unlikely there is a best therapy of acute myeloid leukemia, a best donor, a best conditioning regimen, a best posttransplant immune suppressive regimen etc. and certainly no best combination of these co-variates for your patient.The question Moodie and Krakow tackle is how we can determine the best therapy or combination of therapies for someone receiving a haematopoietic cell transplant. Although the default answer is typically: randomized clinical trials are the gold standard, these inform us of the outcome of a cohort of subjects, not individuals. In many instances, although a new therapy may be shown to be better than an old one in a controlled randomized trial the benefit is not uniformly distributed. Some subjects in the experimental cohort may do worse with the new therapy compared with controls, others better. The question is who are the winners and losers? We cannot do a controlled randomized trial of one person. Moodie and Krakow discuss statistical tools to help us sort this out.Again, please do not be put off by the equations; forgetaboutit. The overriding message is not so complex, and important. We are always standing by on twitter @BMTStats to help. But don't confuse us with Match.com. And, by the way, Freeman Dyson was a professor at the Institute for Advanced Studies at Princeton but never got his PhD.Robert Peter Gale, Imperial College London, and Mei-Jie Zhang, Medical College of Wisconsin, Center for International Blood and Marrow Research (CIBMTR).

Phase I/II multisite trial of optimally dosed clofarabine and low-dose TBI for hematopoietic cell transplantation in acute myeloid leukemia

Clofarabine is an immunosuppressive purine nucleoside analog that may have better anti-leukemic activity than fludarabine. We performed a prospective phase I/II multisite trial of clofarabine with 2 Gy total body irradiation as non-myeloablative conditioning for allogeneic hematopoietic cell transplantation in adults with acute myeloid leukemia who were unfit for more intense regimens. Our main objective was to improve the 6-month relapse rate following non-myeloablative conditioning, while maintaining historic rates of non-relapse mortality (NRM) and engraftment. Forty-four patients, 53 to 74 (median: 69) years, were treated with clofarabine at 150 to 250 mg/m² , of whom 36 were treated at the maximum protocol-specified dose. One patient developed multifactorial acute kidney injury and another developed multiorgan failure, but no other grade 3 to 5 non-hematologic toxicities were observed. All patients fully engrafted. The 6-month relapse rate was 16% (95% CI, 5%-27%) among all patients and 14% (95% CI, 3%-26%) among high-risk patients treated at the maximum dose, meeting the pre-specified primary efficacy endpoint. Overall survival was 55% (95% CI, 40%-70%) and leukemia-free survival was 52% (95% CI, 37%-67%) at 2 years. Compared to a historical high-risk cohort treated with the combination of fludarabine at 90 mg/m² and 2 Gy TBI, protocol patients treated with the clofarabine-TBI regimen had lower rates of overall mortality (HR of 0.50, 95% CI, 0.28-0.91), disease progression or death (HR 0.48, 95% CI, 0.27-0.85), and morphologic relapse (HR 0.30, 95% CI, 0.13-0.69), and comparable NRM (HR 0.85, 95% CI 0.36-2.00). The combination of clofarabine with TBI warrants further investigation in patients with high-risk AML.

Azithromycin Use and Increased Cancer Risk among Patients with Bronchiolitis Obliterans after Hematopoietic Cell Transplantation

Azithromycin exposure during the early phase of allogeneic hematopoietic cell transplantation (HCT) has been associated with an increased incidence of hematologic relapse. We assessed the impact of azithromycin exposure on the occurrence of relapse or new subsequent neoplasm (SN) in patients with bronchiolitis obliterans syndrome (BOS) after HCT who are commonly treated with azithromycin alone or in combination with other agents. In a retrospective study of patients with BOS from 2 large allograft centers, the effect of azithromycin exposure on the risk of relapse or SN was estimated from a Cox model with a time-dependent variable for treatment initiation. The Cox model was adjusted on time-fixed covariates measured at cohort entry, selected for their potential prognostic value. Similar models were used to assess the exposure effect on the cause-specific hazard of relapse, SN, and death free of those events. Sensitivity analyses were performed using propensity score matching. Among 316 patients, 227 (71.8%) were exposed to azithromycin after BOS diagnosis. The corresponding adjusted hazard ratio (HR) in patients exposed to azithromycin versus unexposed was 1.51 (95% confidence interval [CI], 0.90 to 2.55) for relapse or SN, 0.82 (95% CI, 0.37 to 1.83) for relapse, and 2.00 (95% CI, 1.01 to 3.99) for SN. Patients exposed to azithromycin had a significantly lower cause-specific hazard of death free of neoplasm and relapse (adjusted HR, 0.54; 95% CI, 0.34 to 0.89). In conclusion, exposure to azithromycin after BOS after HCT was associated with an increased risk of SN but not relapse.

HLA-Mismatched Microtransplant in Older Patients Newly Diagnosed With Acute Myeloid Leukemia: Results From the Microtransplantation Interest Group

Importance

The outcome of older patients with acute myeloid leukemia (AML) remains unsatisfactory. Recent studies have shown that HLA-mismatched microtransplant could improve outcomes in such patients.

Objective

To evaluate outcomes in different age groups among older patients with newly diagnosed AML who receive HLA-mismatched microtransplant.

Design, Setting, and Participants

This multicenter clinical study included 185 patients with de novo AML at 12 centers in China, the United States, and Spain in the Microtransplantation Interest Group. Patients were divided into the following 4 age groups: 60 to 64 years, 65 to 69 years, 70 to 74 years, and 75 to 85 years. The study period was May 1, 2006, to July 31, 2015.

Exposures

Induction chemotherapy and postremission therapy with cytarabine hydrochloride with or without anthracycline, followed by highly HLA-mismatched related or fully mismatched unrelated donor cell infusion. No graft-vs-host disease prophylaxis was used.

Main Outcomes and Measures

The primary end point of the study was to evaluate the complete remission rates, leukemia-free survival, and overall survival in different age groups. Additional end points of the study included hematopoietic recovery, graft-vs-host disease, relapse rate, nonrelapse mortality, and other treatment-related toxicities.

Results

Among 185 patients, the median age was 67 years (range, 60-85 years), and 75 (40.5%) were female. The denominators in adjusted percentages in overall survival, leukemia-free survival, relapse, and nonrelapse mortality are not the sample proportions of observations. The overall complete remission rate was not significantly different among the 4 age groups (75.4% [52 of 69], 70.2% [33 of 47], 79.1% [34 of 43], and 73.1% [19 of 26). The 1-year overall survival rates were 87.7%, 85.8%, and 77.8% in the first 3 age groups, which were much higher than the rate in the fourth age group (51.7%) (P = .004, P = .008, and P = .04, respectively). The 2-year overall survival rates were 63.7% and 66.8% in the first 2 age groups, which were higher than the rates in the last 2 age groups (34.2% and 14.8%) (P = .02, P = .03, P < .001, and P < .001, respectively). The 1-year cumulative incidences of nonrelapse mortality were 10.2%, 0%, 3.4%, and 26.0% in the 4 age groups and 8.1% in all patients. The median times to neutrophil and platelet recovery were 12 days and 14 days after induction chemotherapy, respectively. Five patients had full or mixed donor engraftment, and 30.8% (8 of 26) of patients demonstrated donor microchimerism. Two patients (1.1%) developed severe acute graft-vs-host disease.

Conclusions and Relevance

Microtransplant achieved a high complete remission rate in AML patients aged 60 to 85 years and higher 1-year overall survival in those aged 60 to 74 years.

The Challenges of Informed Consent in High-Stakes, Randomized Oncology Trials: A Systematic Review

Importance. Oncology trials often entail high-stakes interventions where potential for morbidity and fatal side effects, and for life-prolongation or cure, intensify bioethical issues surrounding informed consent. These challenges are compounded in multistage randomized trials, which are prevalent in oncology. Objective. We sought to elucidate the major barriers to informed consent in high-stakes oncology trials in general and the best consent practices for multistage randomized trials. Evidence Review. We queried PubMed for original studies published from January 1, 1990, to April 5, 2018, that focused on readability, quality, complexity or length of consent documents, motivation and sickness level of participants, or interventions and enhancements that influence informed consent for high-stakes oncologic interventions. Exclusion criteria included articles focused on populations outside industrialized countries, minors or other vulnerable populations, physician preferences, cancer screening and prevention, or recruitment strategies. Additional articles were identified through comprehensive bibliographic review. Findings. Twenty-seven articles were retained; 19 enrolled participants and 8 examined samples of consent documents. Methodologic quality was variable. This body of literature identified certain challenges that can be readily remedied. For example, the average length of the consent forms has increased 10-fold from 1987 to 2010, and patient understanding was shown to be inversely proportional to page count; shortening forms, or providing a concise summary as mandated by the revised Common Rule, might help. However, barriers to understanding that stem from deeply ingrained and flawed sociocultural perceptions of medical research seem more difficult to surmount. Although no studies specifically addressed problems posed by multiple sequential randomizations (such as change in risk-benefit ratio due to time-varying treatment responses or organ toxicities), the findings are likely applicable and especially relevant in that context. Concrete suggestions for improvement are proposed.

Rates and Risk Factors for Post-Traumatic Stress Disorder Symptomatology among Adult Hematopoietic Cell Transplant Recipients and Their Informal Caregivers

Hematopoietic cell transplant (HCT) can cause significant distress in patients and their informal caregivers. Despite advances in reduced-intensity conditioning and supportive care, few recent studies have reported rates of clinically significant post-traumatic stress disorder (PTSD) symptomatology. Goals of the current study were to examine rates of PTSD and distress in patients and caregivers and to identify sociodemographic and clinical risk factors for PTSD. As part of an annual survivorship survey, 2157 HCT recipients and their caregivers were mailed self-report measures of PTSD and distress. Patients also completed self-report measures of sociodemographic information (eg, age, sex, employment status). Clinical variables (eg, time since transplant, transplant type) were captured in the transplant database. A total of 691 recipients (56% age 60 or above at the time of survey, 47% women, median 10.1 years post-HCT) and 333 caregivers provided PTSD data and were included in the current analyses. More caregivers reported PTSD (6.6%) than patients (3.3%; P = .02). Patients or caregivers who had PTSD reported significantly higher distress related to uncertainty, family strain, medical demands, finances, identity, and health burden (P < .0001) compared with those without PTSD. Patient but not caregiver PTSD was associated with more recent transplant (P = .01 and P = .16, respectively). Rates of PTSD are relatively low in long-term survivors of HCT and their caregivers. Nevertheless, results are consistent with other studies of cancer caregiving suggesting that caregivers often experience greater distress than patients. Timely referral to psychosocial services should be offered to both HCT recipients and caregivers reporting symptoms of PTSD.

A cure-rate model for Q-learning: Estimating an adaptive immunosuppressant treatment strategy for allogeneic hematopoietic cell transplant patients

Cancers treated by transplantation are often curative, but immunosuppressive drugs are required to prevent and (if needed) to treat graft-versus-host disease. Estimation of an optimal adaptive treatment strategy when treatment at either one of two stages of treatment may lead to a cure has not yet been considered. Using a sample of 9563 patients treated for blood and bone cancers by allogeneic hematopoietic cell transplantation drawn from the Center for Blood and Marrow Transplant Research database, we provide a case study of a novel approach to Q-learning for survival data in the presence of a potentially curative treatment, and demonstrate the results differ substantially from an implementation of Q-learning that fails to account for the cure-rate.

Success of Immunosuppressive Treatments in Patients with Chronic Graft-versus-Host Disease

Moderate to severe chronic graft-versus-host disease (GVHD) is treated with potent immunosuppressive therapy (IST) to modulate the allo-immune response, control symptoms, and prevent further organ damage. We sought to understand the types of treatments used in clinical practice and the likelihood of successful treatment associated with each. A chart review was performed for 250 adult patients at Fred Hutchinson Cancer Research Center enrolled in a prospective observational study. After a median follow-up of 5.6 years for survivors, approximately one-third were still on IST (of whom half were on fourth or greater line of therapy), one-third were alive and off IST, and one-third had relapsed or died. Approximately half of survivors stopped all IST at least once, although half of these restarted IST after a median of 3.4 months (interquartile range, 2.3 to 8.0) off therapy. Successful discontinuation of IST for at least 9 months was associated with myeloablative conditioning (P = .04), more years since transplant (P = .009), and lack of oral (P < .001) and skin (P = .049) involvement compared with those who had to restart IST. We conclude that patients with chronic GVHD usually receive multiple lines and years of IST, with only a third off IST, alive, and free of malignancy at 5 years after chronic GVHD diagnosis. Patients stopping IST should be cautioned to self-monitor and continue close medical follow-up, especially for 3 to 6 months after stopping IST.

Do We Need Full Donor Chimerism? How Alloreactive Cell Therapies without Substantial Engraftment Might Treat Hematologic Cancers

"Alloreactive cell therapy without substantial engraftment"; (ACT-WiSE) refers to adoptive transfer of natural ("non-engineered") human leukocyte antigen-mismatched lymphocytes to mediate anti-neoplastic alloreactivity in recipients without employing pharmacologic immunosuppression. By definition, ACT-WiSE entails subsequent rejection of most, if not all, donor cells. Macrochimerism is transient and microchimerism may be either short-lived or persistent. This strategy harnesses the anticancer potency of alloreactivity without incurring significant risk of graft-versus-host disease. "Microtransplantation" refers to a form of ACT-WiSE where the donor cell product contains hematopoietic progenitor cells. Microtransplantation therefore accelerates hematopoietic recovery and its immunomodulatory effects may differ from other forms of ACT-WiSE. Recent studies suggest that various forms of ACT-WiSE, including microtransplantation, may improve chemosensitivity in patients with myeloid malignancies, resulting in higher complete remission rates and increased survival. Microtransplantation has also demonstrated promising pilot results in relapsed or refractory Non-Hodgkin and Hodgkin lymphoma. ACT-WiSE and microtransplantation may establish a new class of allogeneic cell therapy of particular relevance to persons not considered candidates for traditional allogeneic hematopoietic cell transplantation (AHCT). Open questions include the optimal timing and cell dose of ACT-WiSE, which donor factors contribute to efficacy, and whether these remissions are durable after eradication of donor cells. We extrapolate from lessons learned in the course of traditional and haploidentical AHCT to propose ways of optimizing ACT-WiSE. We divide these into donor-related strategies (including rational donor selection and boosting NK-cell and T-cell alloreactivity) and patient- related strategies (that may favor development of autologous NK-cell and T-cell mediated anticancer cytotoxicity in the post-ACT-WiSE window).

Tools for the Precision Medicine Era: How to Develop Highly Personalized Treatment Recommendations From Cohort and Registry Data Using Q-Learning

Q-learning is a method of reinforcement learning that employs backwards stagewise estimation to identify sequences of actions that maximize some long-term reward. The method can be applied to sequential multiple-assignment randomized trials to develop personalized adaptive treatment strategies (ATSs)-longitudinal practice guidelines highly tailored to time-varying attributes of individual patients. Sometimes, the basis for choosing which ATSs to include in a sequential multiple-assignment randomized trial (or randomized controlled trial) may be inadequate. Nonrandomized data sources may inform the initial design of ATSs, which could later be prospectively validated. In this paper, we illustrate challenges involved in using nonrandomized data for this purpose with a case study from the Center for International Blood and Marrow Transplant Research registry (1995-2007) aimed at 1) determining whether the sequence of therapeutic classes used in graft-versus-host disease prophylaxis and in refractory graft-versus-host disease is associated with improved survival and 2) identifying donor and patient factors with which to guide individualized immunosuppressant selections over time. We discuss how to communicate the potential benefit derived from following an ATS at the population and subgroup levels and how to evaluate its robustness to modeling assumptions. This worked example may serve as a model for developing ATSs from registries and cohorts in oncology and other fields requiring sequential treatment decisions.

The association of anti-platelet factor 4/heparin antibodies with early and delayed thromboembolism after cardiac surgery

Essentials We evaluated antibody status, thromboembolism and survival after cardiac surgery. Positive antibody tests are common - over 50% are seropositive at 30 days. Seropositivity did not increase thromboembolism or impair survival after cardiac surgery. Results show heparin induced thrombocytopenia antibody screening after surgery is not warranted.

SUMMARY

Background Heparin-induced thrombocytopenia (HIT) is a prothrombotic response to heparin therapy with platelet-activating, anti-platelet factor 4 (PF4)/heparin antibodies leading to thrombocytopenia associated with thromboembolism. Objective We tested the hypothesis that anti-PF4/heparin antibodies are associated with thromboembolism after cardiac surgery. Methods This multicenter, prospective cohort study collected laboratory and clinical data up to 30 days after surgery and longer-term clinical follow-up data. The primary outcome variable combined new arterial or venous thromboembolic complications (TECs) with all-cause death until 90 days after surgery. Laboratory analyses included platelet counts and anti-PF4/heparin antibody titers (GTI ELISA), with a confirmatory excess heparin step and serotonin release assay. Chi-square testing was used to test the relationship between our outcome and HIT antibody seropositivity. Results Initially, 1021 patients were enrolled between August 2006 and May 2009, and follow-up was completed in December 2014. Seropositivity defined by OD > 0.4 was common, being almost 20% preoperatively, > 30% by discharge, and > 60% by day 30. Death (1.7% within 30 days) or TECs (69 in total) were more likely if the partient was seronegative (OD < 0.4), but positivity defined by OD > 1.0 or including an excess heparin confirmatory step resulted in equal incidence of death or TECs, whether the patient was seronegative or seropositive. Incorporating the serotonin release assay for platelet-activating antibodies did not alter these findings. Conclusions Seropositivity for anti-PF4/heparin antibodies does not increase the risk of death or thromboembolism after cardiac surgery. Screening is not indicated, and seropositivity should only be interpreted in the context of clinical evidence for HIT.

TRIAL REGISTRATION

Duke IRB Protocol #00010736.

Harnessing the power of alloreactivity without triggering graft-versus-host disease: how non-engrafting alloreactive cellular therapy might change the landscape of acute myeloid leukemia treatment

Human leukocyte antigen-mismatched leukocyte infusions outside of the context of transplantation are a promising strategy for acute myeloid leukemia. Recent studies using such non-engrafting alloreactive cellular therapy (NEACT) revealed that survival of elderly patients increased from 10% to 39% when NEACT was given following chemotherapy, and that durable complete remissions were achieved in about a third of patients with relapsed or chemorefractory disease. We review the clinical reports of different NEACT approaches to date and describe how although T-cell and NK alloreactivity could generate immediate anti-leukemic effects, long-term disease control may be achieved by stimulating recipient-derived T-cell responses against tumor-associated antigens. Other variables likely impacting NEACT such as the release of pro-inflammatory cytokines from donor-host bidirectional alloreactivity and the choice of chemotherapeutics as well as future avenues for improving NEACT, such as optimizing the cell dose and potential synergies with adjuvant pharmacologic immune checkpoint blockade, are discussed.

Influence of sample collection and storage on the detection of platelet factor 4-heparin antibodies

Heparin-induced thrombocytopenia is a life threatening thrombotic disorder caused by antibodies to platelet factor 4 (PF4) and heparin. Commercial immunoassays are frequently used for the detection of PF4-heparin antibodies, and several studies have reported that higher antibody titers are more frequently associated with adverse events. It is not known if conditions involving sample preparation and/or storage affect the operational characteristics of PF4-heparin immunoassays. We compared the detection of PF4-heparin antibodies from 48 patient samples collected concordantly in serum separator tubes or tubes containing EDTA or sodium citrate. We also examined the effects of extended sample storage on whole blood collected in serum separator, EDTA, or citrate tubes at 4 degrees C for up to 96 hours on antibody detection. We noted that serum or plasma anticoagulated with sodium citrate or EDTA yielded comparable results. In addition, we could not demonstrate any significant sample deterioration after storage at 4 degrees C in any medium for up to 4 days. These findings suggest that PF4-heparin antibodies are largely insensitive to the effects of sample preparation and storage.