A Day 14 Endpoint for Acute GVHD Clinical Trials

The overall response rate (ORR) 28 days after treatment has been adopted as the primary endpoint for clinical trials of acute graft versus host disease (GVHD). However, physicians often need to modify immunosuppression earlier than day (D) 28, and non-relapse mortality (NRM) does not always correlate with ORR at D28. We studied 1144 patients that received systemic treatment for GVHD in the Mount Sinai Acute GVHD International Consortium (MAGIC) and divided them into a training set (n=764) and a validation set (n=380). We used a recursive partitioning algorithm to create a Mount Sinai model that classifies patients into favorable or unfavorable groups that predicted 12 month NRM according to overall GVHD grade at both onset and D14. In the Mount Sinai model grade II GVHD at D14 was unfavorable for grade III/IV GVHD at onset and predicted NRM as well as the D28 standard response model. The MAGIC algorithm probability (MAP) is a validated score that combines the serum concentrations of suppression of tumorigenicity 2 (ST2) and regenerating islet-derived 3-alpha (REG3α) to predict NRM. Inclusion of the D14 MAP biomarker score with the D14 Mount Sinai model created three distinct groups (good, intermediate, poor) with strikingly different NRM (8%, 35%, 76% respectively). This D14 MAGIC model displayed better AUC, sensitivity, positive and negative predictive value, and net benefit in decision curve analysis compared to the D28 standard response model. We conclude that this D14 MAGIC model could be useful in therapeutic decisions and may offer an improved endpoint for clinical trials of acute GVHD treatment.

A Validated Risk Stratification That Incorporates MAGIC Biomarkers Predicts Long-Term Outcomes in Pediatric Patients with Acute GVHD

Acute graft versus host disease (GVHD) is a common and serious complication of allogeneic hematopoietic cell transplantation (HCT) in children but overall clinical grade at onset only modestly predicts response to treatment and survival outcomes. Two tools to assess risk at initiation of treatment were recently developed. The Minnesota risk system stratifies children for risk of nonrelapse mortality (NRM) according to the pattern of GVHD target organ severity. The Mount Sinai Acute GVHD International Consortium (MAGIC) algorithm of 2 serum biomarkers (ST2 and REG3α) predicts NRM in adult patients but has not been validated in a pediatric population. We aimed to develop and validate a system that stratifies children at the onset of GVHD for risk of 6-month NRM. We determined the MAGIC algorithm probabilities (MAPs) and Minnesota risk for a multicenter cohort of 315 pediatric patients who developed GVHD requiring treatment with systemic corticosteroids. MAPs created 3 risk groups with distinct outcomes at the start of treatment and were more accurate than Minnesota risk stratification for prediction of NRM (area under the receiver operating curve (AUC), .79 versus .62, P = .001). A novel model that combined Minnesota risk and biomarker scores created from a training cohort was more accurate than either biomarkers or clinical systems in a validation cohort (AUC .87) and stratified patients into 2 groups with highly different 6-month NRM (5% versus 38%, P < .001). In summary, we validated the MAP as a prognostic biomarker in pediatric patients with GVHD, and a novel risk stratification that combines Minnesota risk and biomarker risk performed best. Biomarker-based risk stratification can be used in clinical trials to develop more tailored approaches for children who require treatment for GVHD.

Phase 2 study of natalizumab plus standard corticosteroid treatment for high-risk acute graft-versus-host disease

Graft-versus-host disease (GVHD) of the gastrointestinal (GI) tract is the main cause of nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation. Ann Arbor (AA) scores derived from serum biomarkers at onset of GVHD quantify GI crypt damage; AA2/3 scores correlate with resistance to treatment and higher NRM. We conducted a multicenter, phase 2 study using natalizumab, a humanized monoclonal antibody that blocks T-cell trafficking to the GI tract through the α4 subunit of α4β7 integrin, combined with corticosteroids as primary treatment for patients with new onset AA2/3 GVHD. Seventy-five patients who were evaluable were enrolled and treated; 81% received natalizumab within 2 days of starting corticosteroids. Therapy was well tolerated with no treatment emergent adverse events in >10% of patients. Outcomes for patients treated with natalizumab plus corticosteroids were compared with 150 well-matched controls from the MAGIC database whose primary treatment was corticosteroids alone. There were no significant differences in overall or complete response between patients treated with natalizumab plus corticosteroids and those treated with corticosteroids alone (60% vs 58%; P = .67% and 48% vs 48%; P = 1.0, respectively) including relevant subgroups. There were also no significant differences in NRM or overall survival at 12 months in patients treated with natalizumab plus corticosteroids compared with controls treated with corticosteroids alone (38% vs 39%; P = .80% and 46% vs 54%; P = .48, respectively). In this multicenter biomarker-based phase 2 study, natalizumab combined with corticosteroids failed to improve outcome of patients with newly diagnosed high-risk GVHD. This trial was registered at www.clinicaltrials.gov as # NCT02133924.

Effective treatment of low-risk acute GVHD with itacitinib monotherapy

The standard primary treatment for acute graft-versus-host disease (GVHD) requires prolonged, high-dose systemic corticosteroids (SCSs) that delay reconstitution of the immune system. We used validated clinical and biomarker staging criteria to identify a group of patients with low-risk (LR) GVHD that is very likely to respond to SCS. We hypothesized that itacitinib, a selective JAK1 inhibitor, would effectively treat LR GVHD without SCS. We treated 70 patients with LR GVHD in a multicenter, phase 2 trial (NCT03846479) with 28 days of itacitinib 200 mg/d (responders could receive a second 28-day cycle), and we compared their outcomes to those of 140 contemporaneous, matched control patients treated with SCSs. More patients responded to itacitinib within 7 days (81% vs 66%, P = .02), and response rates at day 28 were very high for both groups (89% vs 86%, P = .67), with few symptomatic flares (11% vs 12%, P = .88). Fewer itacitinib-treated patients developed a serious infection within 90 days (27% vs 42%, P = .04) due to fewer viral and fungal infections. Grade ≥3 cytopenias were similar between groups except for less severe leukopenia with itacitinib (16% vs 31%, P = .02). No other grade ≥3 adverse events occurred in >10% of itacitinib-treated patients. There were no significant differences between groups at 1 year for nonrelapse mortality (4% vs 11%, P = .21), relapse (18% vs 21%, P = .64), chronic GVHD (28% vs 33%, P = .33), or survival (88% vs 80%, P = .11). Itacitinib monotherapy seems to be a safe and effective alternative to SCS treatment for LR GVHD and deserves further investigation.

Evaluation of Elafin as a Prognostic Biomarker in Acute Graft-versus-Host Disease

Acute graft-versus-host disease (GVHD) is a major cause of mortality in patients undergoing hematopoietic cell transplantation (HCT) for hematologic malignancies. The skin is the most commonly involved organ in GVHD. Elafin, a protease inhibitor overexpressed in inflamed epidermis, was previously identified as a diagnostic biomarker of skin GVHD; however, this finding was restricted to a subset of patients with isolated skin GVHD. The main driver of nonrelapse mortality (NRM) in HCT recipients is gastrointestinal (GI) GVHD. Two biomarkers, Regenerating islet-derived 3a (REG3α) and Suppressor of tumorigenesis 2 (ST2), have been validated as biomarkers of GI GVHD that predict long-term outcomes in patients treated for GVHD. We undertook this study to determine the utility of elafin as a prognostic biomarker in the general population of acute GVHD patients in whom GVHD may develop in multiple organs. We analyzed serum elafin concentrations as a predictive biomarker of acute GVHD outcomes and compared it with ST2 and REG3α in a large group of patients treated at multiple centers. A total of 526 patients from the Mount Sinai Acute GVHD International Consortium (MAGIC) who had received corticosteroid treatment for skin GVHD and who had not been previously studied were analyzed. Serum concentrations of elafin, ST2, and REG3α were measured by ELISA in all patients. The patients were divided at random into equal training and validation sets, and a competing-risk regression model was developed to model 6-month NRM using elafin concentration in the training set. Additional models were developed using concentrations of ST2 and REG3α or the combination of all 3 biomarkers as predictors. Receiver operating characteristic (ROC) curves were constructed using the validation set to evaluate the predictive accuracy of each model and to stratify patients into high- and low-risk biomarker groups. The cumulative incidence of 6-month NRM, overall survival (OS), and 4-week treatment response were compared between the risk groups. Unexpectedly, patients in the low-risk elafin group demonstrated a higher incidence of 6-month NRM, although the difference was not statistically significant (17% versus 11%; P = .19). OS at 6 months (68% versus 68%; P > .99) and 4-week response (78% versus 78%; P = .98) were similar in the low-risk and high-risk elafin groups. The area under the ROC curve (AUC) was 0.55 for elafin and 0.75 for the combination of ST2 and REG3α. The addition of elafin to the other 2 biomarkers did not improve the AUC. Our data indicate that serum elafin concentrations measured at the initiation of systemic treatment for acute GVHD did not predict 6-month NRM, OS, or treatment response in a multicenter population of patients treated systemically for acute GVHD. As seen in previous studies, serum concentrations of the GI GVHD biomarkers ST2 and REG3α were significant predictors of NRM, and the addition of elafin levels did not improve their accuracy. These results underscore the importance of GI disease in driving NRM in patients who develop acute GVHD.

Abstract 868: Heritable cancer mutations in multiple myeloma

Background: Epidemiologic studies have shown familial aggregations of multiple myeloma (MM) and other hematologic malignancies, but little is known about heritable genetic susceptibilities in these patients. The purpose of this study is to investigate the prevalence of known germline cancer-predisposing mutations (CPM) in patients with multiple myeloma (MM).

Methods: We analyzed a set of 895 newly diagnosed MM patients from the Multiple Myeloma Research Foundation (MMRF) CoMMpass registry for whom whole-exome sequencing of germline DNA data was available. We used the clinical annotation pipeline from Sema4, a CLIA- and CAP-certified genetic testing laboratory, in a research context, to identify patients with pathogenic or likely pathogenic CPM according to ACMG variant classification guidelines, and compared their characteristics against those without CPM. Statistical significance was assessed using the Chi-Square and Fisher's Exact tests and defined as a two-sided p value &lt;0.05.

Results: We identified 83 germline CPM in 31 distinct genes in 79 (8.8%) of 895 patients. Homologous recombination (HR) pathway gene mutations were the most common (n = 38, 46%), with CHEK2 being the most frequently mutated gene (n = 10, 12%). Notably, the number of mismatch repair (MMR) gene defects was considerably higher (n = 6, 1:149) than the estimated prevalence in the general population. CPM carriers were significantly more likely to be diagnosed with MM before age 40 (6.3% vs 1.8%, p = 0.025) and to have a family history (FH) of MM or leukemia (16.4% vs 6.3%, p = 0.01) than those without a CPM. Likelihood of having a FH of any malignancy was also significantly higher in the CPM group (70.9% vs 54.5%, p = 0.028). Interestingly, common CHEK2 founder mutations were observed at a much higher rate in patients with a FH of MM or leukemia (8.7% vs 0.68%, p = 0.0013).

Conclusions: Our results suggest that a significant proportion of patients with MM carry germline cancer-predisposing mutations, especially those diagnosed at a very young age (&lt;40 years old), and those with a family history of MM or leukemia. The observation that 6 out of 895 patients with MM had pathogenic MMR variants suggests that MM may be a previously unsuspected component of Lynch syndrome. Common CHEK2 founder mutations were strikingly frequent in patients with a FH of MM, suggesting that FH modifies the penetrance of these variants in MM predisposition, as has been observed for other cancers.

Citation Format: Santiago Thibaud, Aaron Etra, Ryan Subaran, Zachry Soens, Scott Newman, Rong Chen, Ajai Chari, Hearn J. Cho, Sundar Jagannath, Deepu Madduri, David T. Melnekoff, Shambavi Richard, Joshua Richter, Larysa Sanchez, Alessandro Lagana, Samir Parekh, Kenan Onel. Heritable cancer mutations in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 868.

A Case of Rare Autoimmune Pancytopenia Due to Graves’ Disease

Introduction: Graves’ disease has been associated with cytopenias, most commonly anemia. Pancytopenia is a rare complication and is not often encountered.

Case Presentation: A 54-year-old woman with history of multiple sclerosis on alemtuzumab was referred for abnormal thyroid function tests. At the initial visit, the patient reported a 20-pound unintentional weight loss, tremors, sweating and heat intolerance. She was 3 years post-menopausal and had no history of recent viral illness, contrast exposure or family history of thyroid disease. Physical exam revealed an anxious appearing woman with fine tremors in both hands, hyperreflexia but no lid lag or exophthalmos. Labs included TSH &lt;0.005 uIU/mL (0.400-4.2), free T4 2.89 ng/dL (0.80-1.50), TSH receptor binding antibody 8.24 IU/L (&lt; 2.00), TSI 7.27 IU/L (&lt;0.56), WBC 2900/uL (4500-11000), ANC 1746/uL (1900 - 8000), hemoglobin 11.4 g/dL (11.7-15.0) and platelet 207,000/uL (150,000-450,000). Thyroid ultrasound noted sub-centimeter hypoechoic/cystic nodules and 24-hour thyroid uptake showed 56.4% symmetric uptake (upper limit of normal 30%). Due to leukopenia, the patient was started on propranolol and underwent radioiodine ablation with 14.8 mCI. Two weeks later, she reported easily bruising and gum bleeding and her blood work was significant for pancytopenia. The patient was referred to hematology and two bone marrow samples were obtained. Though MDS/MPN was initially suspected based on atypia in both specimens, there were no immunophenotypic, cytogenetic or molecular abnormalities suggesting a neoplastic process. Instead the patient was thought to have autoimmune pancytopenia secondary to Graves’ and the atypia was believed to be secondary to peripheral consumption. She was started on prednisone 1 mg/kg/day with resolution of her cytopenias.

Discussion: Graves’ disease has been associated with hematological abnormalities including isolated anemia (the most common), thrombocytopenia or leukopenia. Pancytopenia is an uncommon complication and is rarely described in the literature. The exact mechanism remains unclear, but may be related to either reduced production of hematopoietic cells from the bone marrow or increased destruction of mature hematopoietic cells due to autoantibodies. Since thyroid hormones are known to increase erythropoietin, this leads to an exaggerated consumption of iron, folic acid and vitamin B12 and can cause various forms of anemias. Leukopenia may be secondary to immunologic destruction whereas thrombocytopenia may be due to antiplatelet antibodies or increased splenic sequestration. Pancytopenia is rare. Our patient was treated with high dose prednisone with resolution of her pancytopenia, which suggests an autoimmune process as the mechanism. Our case showcases a rare complication of Graves’ disease and highlights that high dose steroid therapy may improve cytopenias associated with this condition.

Current and Emerging Targeted Therapies for Acute Graft-Versus-Host Disease

Acute graft-versus-host disease (GVHD), the major complication after allogeneic hematopoietic cell transplant (HCT), develops in approximately 50% of patients. The primary treatment is high-dose systemic steroids, but treatment failure is common, and steroid-refractory (SR) GVHD is the leading cause of non-relapse mortality after allogeneic HCT. Ruxolitinib became the first treatment for SR GVHD to obtain US Food and Drug Administration approval, and other new treatments are actively being studied. We searched the literature using the PubMed database and clinical trials using ClinicalTrials.gov to identify the most promising new treatments for GVHD. In this review, we categorize potential new treatments for GVHD by their mechanism of action (e.g., antibodies that deplete T cells or prevent their trafficking to target tissues, proteasome inhibitors, tyrosine kinase inhibitors, and other agents) and summarize the results from clinical trials.

Abstract 3849: Analysis of the mutation rate in T lymphoblastic leukemia cell lines

To account for the high number of somatic mutations in cancer, it has been hypothesized that genomic instability is necessary for malignant transformation. We previously demonstrated that PIG-A is a useful reporter gene for quantitating somatic mutations. PIG-A encodes an enzyme that is essential for the biosynthesis of the glycosylphosphatidylinositol (GPI) anchor, by which a set of membrane proteins are covalently linked to the cell surface. PIG-A is X-linked, and a broad spectrum of mutations occurring in only one allele can produce the GPI (-) phenotype. We have demonstrated occult populations of spontaneously arising blood cells with PIG-A mutations in normal individuals, and shown that among ex vivo blasts from patients with ALL, the frequency (f) of GPI(-) cells appeared trimodal, with some samples overlapping the normal range, whereas others were orders of magnitude higher. f values in T cell leukemias generally fell in the middle group. Here, we have studied a panel of cell lines derived from patients with T cell ALL and measured the mutation rate per cell division (μ) as an assessment of genomic instability. First, cells were stained with anti-CD59-FITC and sorted by collecting the upper 50th percentile, to eliminate pre-existing mutants. This purified GPI(+) population was counted and expanded in culture for 18 days, and then recounted to estimate cell divisions (d) in vitro. To estimate the frequency of new mutants arising in culture, the cells were first incubated with the FLAER reagent conjugated to Alexa 488, then a mixture of anti-CD55 and anti-CD59 antibodies, then a rabbit anti-mouse FITC secondary conjugate, followed by PE conjugated antibodies specific for transmembrane proteins(CD45 or HLA). Cells were gated based on light scatter, exclusion of propidium iodide, and expression of the transmembrane proteins; GPI(-) negative cells were defined as having &lt;4% of the FITC/Alexa fluorescence as the population overall. Mutation rate was calculated by the formula μ = f divided by d. We found that one sample, derived from the cell line P12, demonstrated a mutation rate of 17.5 × 10−7 per cell division, whereas for the cell lines CEM, CUTTL, LOUCY, and HPBALL, μ ranged from 50 to 60 × 10−7. For comparison, we sorted, expanded, and analyzed cultures of T cells derived from 4 normal donors, stimulated with PHA, cytokines, and bead-immobilized antibodies, and here μ was generally lower, ranging from 1.5 × 10−7 to 18 × 10−7 (p &lt;0.04, 2-sided non parametric test). The subtle elevation in μ in T cell ALL was in contrast to cell lines that we have studied from Burkitt's lymphomas, where the distribution was bimodal and where the μ values were all either below 25 × 10−7 (4 samples) or &gt; 200 × 10−7(3 samples, p = 0.01, Fisher's exact test). We conclude that T cell ALL samples may demonstrate a more mild form of genomic instability than in Burkitt's lymphoma, and that genomic instability, as determined by this assay, is not absolutely required for leukemogenesis.

Citation Format: David J. Araten, Erik Sherman, Aaron Etra. Analysis of the mutation rate in T lymphoblastic leukemia cell lines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3849. doi:10.1158/1538-7445.AM2015-3849