Prior Bone Marrow Transplantation Research Articles

Ambulatory teclistamab administration in patients with relapsed/refractory multiple myeloma.

11146 Background: Teclistamab (Tec) is the first B-Cell Maturation antigen (BCMA)xCD3 bispecific antibody FDA approved for the treatment of relapsed or refractory multiple myeloma (RRMM) in patients who have received ≥4 prior lines of therapy. The phase 1-2 MajesTec-1 study raised concerns for cytokine release syndrome (CRS)/immune effector cell-associated neurotoxicity syndrome (ICANS). 48-hour inpatient observation is recommended for step-up dosing, which imposes financial and logistical burdens. We report our institutional experience with ambulatory Tec administration. Methods: Our inpatient/outpatient (IPOP) hybrid nursing unit is staffed with specialized nurses, advanced practice providers, and attending physicians. Our patients treated in IPOP must live within 1 hour of the hospital and have a 24-hour caregiver. Patients were treated with the recommended step-up dosing schedule. CRS grading and ICE scoring were performed daily. Both CRS and ICANS were graded according to the ASTCT grading systems. We collected toxicities until the second full treatment dose, at which point hospitalization is no longer recommended. Results: In total, 25 patients were treated with Tec between January 2023 to December 2023. The median age was 70 years old (range 59-89), with a median of 6 prior lines of therapy. One patient was dialysis dependent prior to starting Tec. All patients were triple class refractory. Thirteen patients (52%) received prior bone marrow transplant. One (4%) patient received prior anti-BCMA CAR-T therapy. Seventeen patients (68%) required admission during the Tec ramp-up period. CRS was observed in 15 (60 %) patients, all of which were grade I/II events. Fourteen of these patients were hospitalized for CRS. They were admitted for median number of 2 hospital days (range 1-6). Tocilizumab was administered for Grade 2 CRS in 3 patients (12%). ICANS was reported in 4 (16%) patients. Two of those patients developed Grade 2 ICANS which completely resolved with dexamethasone. The median number of admitted hospital days for these patients was 3 days (range 2-49). Neutropenia with ANC < 500 was seen in only 1 (4%) patient. Grade 3/4 infections were seen in 3 (12%) patients during the ramp-up period. Conclusions: Tec administration through an inpatient/outpatient hybrid model is safe and feasible. CRS was common but low grade and short lived. ICANS was observed, but remained low grade and may be attributable to our older patient population. As our center gained experience with the Tec management, we noticed lower rates of admission for low grade CRS. Lower incidences of infections and neutropenia demonstrate that these complications emerge in the months after starting therapy. Future studies will help identify patients who are higher risk for CRS and ICANS during ramp-up treatment and may pave the way for prophylactic interventions and outpatient administration.

Low-risk pneumatosis intestinalis in the pediatric surgical population.

Pneumatosis intestinalis (PI, presence of air in bowel wall) develops in a variety of settings and due to a variety of insults which is then characterized by varying severity and clinical course. Anecdotally, many of these cases are benign with few clinical sequelae; however, we lack evidence-based guidelines to help guide management of such lower-risk cases. We aimed to describe the clinical entity of low-risk PI, characterize the population of children who develop this form of PI, determine if management approach or clinical outcomes differed depending on the managing physician's field of practice, and finally determine if a shortened course of NPO and antibiotics was safe in the population of children with low-risk PI. We performed a retrospective review of all children over age 1year treated at Children's Hospital Colorado (CHCO), between 2009 and 2019 with a diagnosis of PI who did not also have a diagnosis of cancer or history of bone marrow transplant (BMT). Data including demographic variables, clinical course, and outcomes were obtained from the electronic medical record. Low-risk criteria included no need for ICU admission, vasopressor use, or urgent surgical intervention. Ninety-one children were treated for their first episode of PI during the study period, 72 of whom met our low-risk criteria. Among the low-risk group, rates of complications including hemodynamic decompensation during treatment, PI recurrence, Clostridium difficile colitis, and death did not differ between those who received 3days or less of antibiotics and those who received more than 3days of antibiotics. Outcomes also did not differ between children cared for by surgeons or pediatricians. Here, we define low-risk PI as that which occurs in children over age 1 who do not have a prior diagnosis of cancer or prior BMT and who do not require ICU admission, vasopressor administration, or urgent surgical intervention. It is likely safe to treat these children with only 3days of antibiotic therapy and NPO. Level III.

Survivorship Struggles: Navigating Etiologies and Clinical Parameters of Febrile Neutropenia During Induction Chemotherapy in Acute Leukemia Patients.

Background Acute leukemia, characterized by the uncontrolled proliferation of immature white blood cell precursors, poses significant challenges during induction chemotherapy, including the elevated risk of febrile neutropenia and its associated complications. Our study aims to explain the clinical and etiological parameters of these patients in a resource-limited setting. Methods This retrospective study focused on a total of 102 adult patients with acute leukemia who developed febrile neutropenia during the induction chemotherapy phase. Patients with disease relapse, prior bone marrow transplantation, and cases of acute promyelocytic leukemia were excluded from the study. Demographical characteristics, symptoms at presentation, diagnoses, infectious causes, and outcomes were systematically reported. Infectious etiologies and detailed culture reports were meticulously tabulated, and subsequent data were analyzed. Results Of the 102 patients, 43 (42.2%) were males, with a mean age of 31.9 ± 6.5 years. During the induction chemotherapy, a total of 31 patients died of complicated febrile neutropenia. Severe vomiting was the most common symptom present in 37 (36.2%), followed by cough in 35 (34.3%) and loose stools in 28 (27.5%). Community-acquired pneumonia, neutropenic sepsis, and neutropenic colitis were among the most common etiologies of febrile neutropenia. A total of 72 (70.6%) patients had culture-proven multidrug-resistant Gram-negative bacteremia that contributed to poor outcomes. Conclusions Acute leukemia patients undergoing induction chemotherapy face high infection-associated mortality due to their immunocompromised state. Inadequate infection control measures and antimicrobial resistancecontribute to the emergence of multidrug-resistant organisms. Enhanced infection prevention strategies and evidence-based antibiotic prescription guidelines are need of time in resource-limited settings such as Pakistan to address febrile neutropenia complications and bridge the existing care gap in its management.

Abstract A030: Fusion between macrophages and cancer cells up-regulates signal regulatory protein pathway and contributes to malignant progression of pancreatic cancer after radiation

Abstract Introduction: Fusion between tumor cells with leukocytes contributes to tumor heterogeneity, resulting in tumorigenesis, metastasis, and treatment resistance. Recent studies demonstrate that an inflammatory microenvironment enhances tumor-macrophage fusion. We hypothesize that tumor-macrophage fusion hybrids contribute to radiation induced pancreatic cancer progression. Materials and Methods: Tumor tissues of female patients receiving previous bone marrow transplantation (BMT) from male donors due to leukemia/lymphoma were collected for Y chromosome and immunofluorescence study. Murine subcutaneous tumor models of cre-loxP or dual fluorescence system were established to demonstrate fusion between Pan02, a murine pancreatic adenocarcinoma cell line, and stromal cells of ROSA (Gt(ROSA)26Sor tm4(ACTB-tdTomato,-EGFP)Luo/Jnarl) mice with or without local radiation exposure. KC (pdx-1-cre-KrasLSL-G12D) mice, were given whole body irradiation followed by BMT from ROSA mice to measure fusion between pancreatic cancer and hematopoietic cells. Liposomal chlodronate, a macrophage depleting agent, and immunofluorescence staining of fusion hybrids in ROSA mice tumors were used to demonstrate macrophage as a fusion partner. Fusion hybrid clones of murine/human pancreatic adenocarcinoma cells with macrophages were selected from co-culture and sorting followed by studies including ploidy, clonogenicity, migration and radio-sensitivity. Affymetrix microarray analysis was used to find differentially expressed genes of fusion hybrids. Results: Fusion phenomenon was demonstrated by showing colocalization of Y chromosomes with epithelial markers in cancer tissues from female patients receiving prior BMT from male donors. Fusion hybrids were found in pancreas tumors of KC mice after BMT from ROSA mice. Fusion hybrids within tumors increased by time, three folds within 6 weeks; and 2.5 folds after 20Gy radiation exposure. Liposomal clodronate reduced fusion hybrids and tumor growth. Immunofluorescence stain of tumor tissues demonstrated CD11b(+) macrophage to be the major fusion partner. Purified Fusion hybrids showed enhanced migration, proliferation, aneuploidy and radio-resistance. Model based gene analysis of microarray study disclosed signal regulatory protein (SIRP) signal pathway was significantly upregulated in fusion hybrids. Upregulated SIRP signal molecules, including DAP12, PyK2, were validated by immunoblots. Silencing DAP12 in myeloid cells from human peripheral blood showed decreased fusion rate with Panc-1 cells. DAP12mRNA depletion in Panc-1 fusion hybrids disclosed enhanced radio-sensitivity. Defactinib (VS6063), a PyK2 inhibitor, reduced fusion phenomenon and suppressed pancreatic tumor growth of mice after local radiation. Conclusions: Fusion between pancreatic cancer cells and macrophages contribute to radiation enhanced malignant progression of pancreatic cancer. SIRP signal pathway is a potential target to disrupt fusion phenomenon and ameliorate pancreatic cancer progression after radiation. Citation Format: Hui Ju Ch'ang, Yi-Chih Tsai, Ting Wei Li, Rui-Jun Liu, Tze-Sing Huang, Sse-Pei Wan, Su-Liang Chen, Shih-Sheng Jiang. Fusion between macrophages and cancer cells up-regulates signal regulatory protein pathway and contributes to malignant progression of pancreatic cancer after radiation [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A030.

Venetoclax for Acute Myeloid Leukemia in Pediatric Patients: A Texas Medical Center Experience.

The BCL-2 inhibitor venetoclax improves survival for adult patients with acute myeloid leukemia (AML) in combination with lower-intensity therapies, but its benefit in pediatric patients with AML remains unclear. We retrospectively reviewed two Texas Medical Center institutions' experience with venetoclax in 43 pediatric patients with AML; median age 17 years (range, 0.6-21). This population was highly refractory; 44% of patients (n = 19) had ≥3 prior lines of therapy, 37% (n = 16) had received a prior bone marrow transplant, and 81% (n = 35) had unfavorable genetics KMT2A (n = 17), WT1 (n = 13), FLT3-ITD (n = 10), monosomy 7 (n = 5), TP53 (n = 3), Inv(3) (n = 3), IDH1/2 (n = 2), monosomy 5 (n = 1), NUP98 (n = 1) and ASXL1 (n = 1). The majority (86%) received venetoclax with a hypomethylating agent. Grade 3 or 4 adverse events included febrile neutropenia in 37% (n = 16), non-febrile neutropenia in 12% (n = 5), anemia in 14% (n = 6), and thrombocytopenia in 14% (n = 6). Of 40 patients evaluable for response, 10 patients (25%) achieved complete response (CR), 6 patients (15%) achieved CR with incomplete blood count recovery (CRi), and 2 patients (5%) had a partial response, (CR/CRi composite = 40%; ORR = 45%). Eleven (25%) patients received a hematopoietic stem cell transplant following venetoclax combination therapy, and six remain alive (median follow-up time 33.6 months). Median event-free survival and overall survival duration was 3.7 months and 8.7 months, respectively. Our findings suggest that in pediatric patients with AML, venetoclax is well-tolerated, with a safety profile similar to that in adults. More studies are needed to establish an optimal venetoclax-based regimen for the pediatric population.

A PHASE 2/3, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED STUDY OF MITAPIVAT IN PATIENTS WITH SICKLE CELL DISEASE

The key pathology in sickle cell disease (SCD), a life-threatening, hereditary hemoglobin (Hb) disorder, is red blood cell (RBC) sickling due to polymerization of deoxygenated sickle Hb (HbS), which can be exacerbated by increased levels of the glycolytic metabolite 2,3-diphosphoglycerate (2,3-DPG) and decreased ATP. Sickled RBCs are rigid, non-deformable, and fragile, resulting in vaso-occlusive pain and chronic hemolysis. Current SCD treatment options are limited; therefore, there is an unmet need for safe, effective therapies that alleviate both anemia and pain. Activation of the key RBC glycolytic enzyme pyruvate kinase (PKR) by oral mitapivat decreases 2,3-DPG and increases ATP, which may reduce HbS polymerization, RBC sickling, and hemolysis in SCD. Data from the phase (ph) 1 National Institutes of Health multiple ascending dose study of up to 100 mg mitapivat twice daily (BID) in patients with SCD (NCT04000165) showed that mitapivat was safe and tolerable, increased ATP and decreased 2,3-DPG in a dose-dependent manner, and improved anemia and hemolysis. Here we report the study design of RISE UP (NCT05031780, EudraCT: 2021-001674-34), a ph 2/3, double-blind, randomized, placebo (PBO)-controlled, multicenter study evaluating the efficacy and safety of mitapivat in patients (pts) with SCD. Eligible: pts aged ≥16 yrs (≥18 yrs [France and Germany]) with documented SCD (HbSS, HbSC, HbSβ 0 /HbSβ + thalassemia, other variants), 2–10 sickle cell pain crises (SCPCs; acute pain requiring intervention, acute chest syndrome, priapism, hepatic or splenic sequestration) in the prior 12 months, and Hb 5.5–10.5 g/dL. If on hydroxyurea (HU), the dose must be stable for ≥ 90 days before starting study drug. Ineligible: pts receiving regular blood transfusions, with severe kidney or hepatobiliary disease, current SCD therapies except HU, or prior gene therapy, bone marrow or stem cell transplantation. In the double-blind ph 2 part, 69 pts will be randomized (1:1:1) to 50 mg or 100 mg mitapivat, or PBO BID for 12 weeks (wk). The primary objective is to determine the recommended ph 3 mitapivat dose by evaluating anemia and safety vs PBO via the following endpoints: Hb response (≥ 1.0 g/dL increase in average (avg) Hb concentration over Wk 10–12 vs baseline [BL]), and type, severity, and relationship of adverse events (AEs) and serious AEs. In the double-blind ph 3 part, 198 pts who did not participate in ph 2 will be randomized (2:1) to the selected ph 3 mitapivat dose or PBO BID for 52 wk. The primary objectives are to determine the effect of mitapivat vs PBO on anemia, measured by Hb response (≥ 1.0 g/dL increase in avg Hb concentration over Wk 24–52 vs BL), and the effect of mitapivat vs PBO on SCPC, measured by annualized rate of SCPCs. Key secondary endpoints: avg change from BL in Hb concentration, indirect bilirubin, percent reticulocyte, and Pt-Reported Outcomes Measurement Information System ® Fatigue 13a Short Form score over Wk 24–52; and annualized frequency of SCPC admissions. Pts who complete the double-blind period will be eligible to receive mitapivat in the open-label extension period in each ph. Pending. N/A. This ph 2/3 study will investigate the efficacy and safety of mitapivat in pts with SCD. Enrollment is currently ongoing.

P1482: PATIENTS WITH SEVERE SICKLE CELL DISEASE ON STANDARD OF CARE TREATMENT ARE VERY UNLIKELY TO BECOME VOC FREE FOR ONE YEAR: A COHORT STUDY OF MEDICAID ENROLLEES

Background: Sickle cell disease (SCD) patients have frequent vaso-occlusive crises (VOCs), which impact their quality of life, contribute to organ damage and failure, and are associated with increased mortality. An ongoing, open-label Ph3 clinical trial with CTX001, an investigational, autologous, ex vivo CRISPR/Cas-9-based gene edited therapy, in patients with severe SCD, is evaluating the proportion of patients who become VOC-free for at least 1 year after CTX001 treatment. Thus, it is important to know the proportion of patients with severe SCD on standard-of-care (SOC) who become VOC-free over time to provide context for the efficacy of CTX001 in eliminating VOCs in severe SCD. Aims: To contextualize the efficacy of CTX001 in eliminating VOCs in patients with severe SCD, we used nationwide Medicaid claims data from 2000 to 2014 to assess the proportion of patients on SOC who became VOC-free during a 1-year follow-up. The inclusion/exclusion criteria were similar to those of the Ph3 clinical trial of CTX001 in patients with severe SCD. Methods: A cohort of patients 12-35 years old with SCD was identified based on ≥1 inpatient claim or ≥2 outpatient claims for SCD after at least 2 years of continuous Medicaid enrollment. The date patients met the SCD case algorithm was defined as the cohort entry date. The 2-year period preceding the cohort entry date was defined as the baseline period. Consistent with the inclusion criteria in the CTX001 Ph3 trial, we restricted this population to severe SCD defined by ≥2 VOCs per year in each of 2 consecutive years (total of ≥4 VOCs over 2 years) at baseline. A VOC was identified using ICD diagnosis codes in hospitalization and ER visit claims for acute pain crisis, acute chest syndrome, priapism, and splenic sequestration. Additional exclusion criteria that were operationalizable using claims data included prior bone marrow transplant, moyamoya syndrome or history of stroke, low left heart function, low lung diffusing capacity (including pulmonary hypertension), advanced liver disease, decreased kidney function, significant bleeding disorder, prior malignancy or myelodysplasia, and select infections. We further restricted the cohort to patients with 1-year of continuous Medicaid enrollment (or less if any deaths) following the cohort entry. The primary outcome was the proportion of patients with 0 VOCs during a 1-year follow-up. Results: A total of 5,874 patients with severe SCD were identified [mean (SD) age: 20.5 (6.0) years, 54.4% female, 87% African Americans]. Patients had a mean of 5.1 VOCs, 4.7 ER visits and 3.6 all-cause hospitalizations per year during the 2-year baseline period. Hydroxyurea was used in 37.5%, opioid analgesics in 88.7%, and NSAIDs in 71.9%. The proportion of patients with 0 VOCs during the 1-year follow-up was 9.1% (95% CI: 8.4, 9.9). When stratified by the number of VOCs at baseline, patients with higher numbers of VOCs had a lower proportion of 0 VOCs in the 1-year follow-up (Table). Image:Summary/Conclusion: Fewer than 10% of patients with severe SCD with at least 2 VOCs per year in the prior 2 years at baseline became VOC-free for 1 year with SOC in this nationwide cohort of Medicaid enrollees. This demonstrates that patients with severe SCD are very unlikely to become VOC-free over a 1-year period and provides context for the efficacy of gene therapies in eliminating VOCs. These data also highlight the urgent need to develop effective therapies for patients with severe SCD as ~90% of patients continue to have VOCs, which are life-limiting and life-threatening events.

CXCL1, CXCL10 and CXCL12 Chemokines are Variously Expressed in Acute Myeloid Leukemia Patients Prior and Post Bone Marrow Transplantation.

Aim:The chemokine-receptor axes play parts in development of leukemia, CXCL1, CXCL10 and CXCL12 are involved in immune responses. Thus, we have examined the serum levels of these chemokines in parallel with their related cognate receptors (CXCR1, CXCR3 and CXCR4) in AML (acute myeloid leukemia) patients prior and post BMT (bone marrow transplantation) therapy. Main methods: Clinical specimens were collected from 46 AML patients (23 M1 and 23 M3 subtypes) before/after BMT. CXCL1, CXCL10 and CXCL12 concentrations were determined by ELISA. The mRNA levels of the related receptors were detected by QRT_PCR. Data were analyzed by T-test, χ2 and ANOVA statistical methods in SPSS software version 18. A difference was regarded significant if P value < 0.05. Key findings:Our results indicated that the elevated levels of CXCL12 in AML patients were remained unchanged after transplantation. The CXCL10 concentration was decreased in patients. All studied chemokines were elevated in BMT patients with history of 9 times PLT transfusion. In patients who received BMT from siblings CXCL1 and CXCL10 have been elevated, whereby they were compared to patients who received BMT from parents while CXCL12 sustained unchanged in groups. Serum measures of CXCL1 and CXCL10 were induced in acute and chronic GVHD patients in compare to these without GVHD. Significance:According to the results, it can be concluded that these chemokines play fundamental parts in pathogenesis of both AML and BMT. It is worthy to note that chemokines could be used as diagnostic markers alongside with possible promising therapeutic targets.

Polatuzumab vedotin (Pola) + rituximab (R) + lenalidomide (Len) in patients (pts) with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL): Primary analysis of a phase 1b/2 trial.

7512 Background: The combination of Pola-R-Len may enhance anti-tumor response in R/R DLBCL. We report the primary analysis of the R/R DLBCL cohort in a Phase 1b/2 study (GO29834; NCT02600897). Methods: Pts received induction with 6 x 28-Day (D) cycles (C) of: Pola 1.8mg/kg intravenous (IV; C1−6: D1); R 375mg/m2 IV (C1−6: D1) and oral Len 10–20mg (dose escalation) or recommended Phase 2 dose (RP2D) daily on D1–21. Pts with a response at end of induction (EOI) received 6 months (mo) consolidation with R 375mg/m2 (D1 every 2 mo) and Len 10mg (D1–21 monthly). Primary endpoints were safety/tolerability and positron emission tomography (PET)-complete response (CR) rate at EOI by independent review committee (IRC) by modified Lugano criteria. Results: At primary analysis (Sep 08, 2020), 57 pts were enrolled. Median age was 71 years (range 28–92); male (67%); Ann Arbor Stage III–IV (86%); International Prognostic Index 3–5 (60%); median 2 prior therapies; prior bone marrow transplant (11%); prior CAR-T therapy (5%); primary refractory (49%) and refractory to last therapy (65%). Grade 3–4 adverse events (AEs) were experienced by 75% of pts, most commonly, neutropenia (58%), thrombocytopenia (14%), infections (14%) and anemia (11%). AEs led to Len dose reduction in 25% and interruption in 63% of pts. One Grade 5 treatment-related AE (neutropenic sepsis) was reported. In total, 49 pts were treated at RP2D (Pola 1.8mg/kg + Len 20mg). IRC PET-CR rate at EOI was 29% (Table). A best overall response (BOR) assessed by investigator (INV) was seen in 36/49 (74%) pts with 17/49 (35%) pts achieving a CR; of these, 14/17 (82%) remain in remission at the cutoff date. Median duration of response (DOR) was 8.1 mo (95% confidence interval [CI]: 4.7–not evaluable [NE]). After a median follow-up of 9.7 mo, median progression-free survival (PFS) and overall survival (OS) were 6.3 mo (95% CI: 4.5–9.7) and 10.9 mo (95% CI: 7.4–NE), respectively. Conclusions: Our study of the novel triplet combination, Pola-R-Len, demonstrates a tolerable safety profile. This first efficacy report of Pola-R-Len shows promising activity in a difficult-to-treat R/R DLBCL population, particularly in pts achieving CR, a large proportion of whom remain in remission at the cutoff date. Further evaluation of Pola-R-Len and the impact of consolidation therapy is warranted to address the significant unmet need in this patient population. Clinical trial information: NCT02600897. [Table: see text]

BCL-XL exerts a protective role against anemia caused by radiation-induced kidney damage.

Studies of gene-targeted mice identified the roles of the different pro-survival BCL-2 proteins during embryogenesis. However, little is known about the role(s) of these proteins in adults in response to cytotoxic stresses, such as treatment with anti-cancer agents. We investigated the role of BCL-XL in adult mice using a strategy where prior bone marrow transplantation allowed for loss of BCL-XL exclusively in non-hematopoietic tissues to prevent anemia caused by BCL-XL deficiency in erythroid cells. Unexpectedly, the combination of total body γ-irradiation (TBI) and genetic loss of Bcl-x caused secondary anemia resulting from chronic renal failure due to apoptosis of renal tubular epithelium with secondary obstructive nephropathy. These findings identify a critical protective role of BCL-XL in the adult kidney and inform on the use of BCL-XL inhibitors in combination with DNA damage-inducing drugs for cancer therapy. Encouragingly, the combination of DNA damage-inducing anti-cancer therapy plus a BCL-XL inhibitor could be tolerated in mice, at least when applied sequentially.

Safety and Efficacy of CD19 CAR T-Cells for Pediatric Relapsed Acute Lymphoblastic Leukemia with Active CNS Involvement

Background: CAR T cells targeting CD19 are approved for patients with relapsed or refractory acute lymphoblastic leukemia (ALL), failing two or more prior therapies. The central nervous system (CNS) is a known sanctuary site of ALL. Despite observations of CAR T-cells trafficking to the CNS in patients, most clinical trials excluded patients with active CNS leukemia, partially for concerns of neurotoxicity. Methods: We conducted an international retrospective study of patients who were referred to CAR T-cell therapy for relapsed ALL with CNS involvement. Results: We reviewed data of 27 patients (16 males and 11 females) from 8 centers who were treated with CD19 CAR T-cells for ALL relapse involving the CNS. Fifteen patients had a prior bone marrow transplantation, and in seven total body irradiation was given. Four additional patients received previous cranial radiation. At time of CAR T-cell order or clinical trial inclusion, ten patients had an isolated CNS relapse, and 17 had a combined CNS and marrow relapse. The median number of cells in the CSF of patients at enrollment was 65 (range 0-5670), and 16 of 21 patients who had imaging performed showed leukemia-associated changes in brain MRI. All patients received bridging chemotherapy between enrolment and lymphodepletion, including intrathecal chemotherapy alone or in combination with systemic chemotherapy and/or radiation. At lymphodepletion, 15 patients had cleared CNS disease while 12 had active CNS blasts or imaging lesions. Following lymphodepletion with fludarabine and cyclophosphamide, patients received 2nd-generation CAR T cells: 15 patients treated with a CD19-4-1BB CAR and 12 with a CD19-CD28 CAR. Cytokine release syndrome (CRS) occurred in 20 patients: 12 patients (100%) treated with CD19-CD28 CARs and 8 with CD19-4-1BB CARs (53%, p=0.006). Immune-effector cell neurotoxicity (ICANS) was diagnosed in 11 patients, 9 of 12 following CD28-based CARs, and 3 of 15 following 41BB-based CARs (p=0.004). Patients with active CNS-disease prior to lymphodepletion also had a higher rate of ICANS (75% vs 20%, p=0.004) but not of CRS. One patient died of grade 5 ICANS on day +7 following CD28-based CARs for an isolated CNS relapse. Twenty-four of 26 evaluable patients (92%) had a complete remission following CAR T-cells. Nine patients were further referred to an allogeneic transplant, all following CD28-based CARs. Overall, six patients had relapsed - in four relapse involved bone marrow, and in two the CNS. Conclusions: In this cohort of patients with active CNS disease treated with CD19 CAR T-cells, we report a high remission rate in previously heavily pre-treated patients. Toxicities are significant, and associated mostly with the costimulatory domain of the CAR (CD28&amp;gt;41BB) and the presence of active CNS disease at lymphodepletion. This may be informative when designing future clinical studies of CAR T cell therapy for patients with CNS manifestations of ALL. Disclosures Jacoby: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Lonza: Membership on an entity's Board of Directors or advisory committees. Ghorashian:Novartis: Honoraria; UCLB: Patents &amp; Royalties; Amgen: Honoraria. De Moerloose:Novartis: Consultancy. Rossig:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; EUSA Pharma: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria. von Stackelberg:Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Morphosys: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau; Shire: Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, advisory committees and speakers bureau, Speakers Bureau. Bourquin:Servier: Other: Travel Support. OffLabel Disclosure: We describe the use of commercial and investigational CAR T-cell products

Abstract B23: The role of bone marrow transplantation in patients with Fanconi anemia and head and neck squamous cell carcinoma receiving radiotherapy: An examination of the International Fanconi Anemia (IFAR) Registry

Abstract Introduction: Fanconi anemia (FA) patients have a high predilection for developing aggressive head and neck squamous cell carcinoma (HNSCC) at an early age. Because of their aggressive HNSCC, these patients frequently require multiple modality treatment, including radiation therapy. However, their underlying chromosomal instability makes giving radiation to these patients difficult because of increased radiation-induced complications. In order to better understand this problem, we evaluated a large population of FA patients with HNSCC who received radiation therapy for HNSCC. Hypothesis: FA patients who have undergone prior bone marrow transplant (BMT) and present with head and neck squamous cell carcinoma (HNSCC) demonstrate decreased relative risk of radiation-induced complications compared to FA patients who have not received BMT. Study Design: Retrospective Cohort Study Methods: Demographic information, genotypic data, prognostic factors, therapeutic management, and survival outcomes for FA patients enrolled in the International Fanconi Anemia Registry (IFAR) who developed HNSCC from 1981-2017 were analyzed. Results: Data were collected from the IFAR registry for n=50 patients. The mean age at time of HNSCC diagnosis was 30.5 + 9.0 years, and 36% of total patients were male. 42% of the patients received adjuvant or neoadjuvant radiotherapy for HNSCC, with the most common subsites involving the oral tongue (n=8), followed by alveolus (n=3) and supraglottis (n=2). The average dose given was 48.8 + 16.9 Gy over a 28- to 70-day period. Among patients receiving radiotherapy, 24% had received a bone marrow transplant. No patients who had a prior BMT were noted to develop pancytopenia as a radiation-related complication, while 68% of those without prior BMT developed pancytopenia from radiation. 6/16 patients who did not undergo transplant completed the full course of radiation, while 4/5 BMT patients were able to complete treatment. Both mucositis and sepsis were secondary complications more common in the non-BMT group (56% vs. 40%, and 12% vs. 0%, respectively). The relative risk of pancytopenia among patients receiving BMT and adjuvant radiation was 0.15 (95% CI 0.01-2.2); however, this was not statistically significant given the small BMT-group sample size (p=0.17). Interestingly, 80% of patients in the BMT group exhibited genetic mutations of the Fanconi complementation group C. Among patients who received a BMT and adjuvant radiotherapy, 5 patients died of XRT-related complications, while only 1 patient died from these complications in the BMT group. Conclusion: While it is well known that FA patients have a high predilection for developing aggressive HNSCC at an early age, among the patients who received preradiation bone marrow transplant the incidence of radiation-induced pancytopenia was reduced. This reduction suggests that FA patients undergoing radiotherapy for HNSCC may exhibit less adverse side effects of radiation treatment if they received a prior BMT. Citation Format: Ade Obayemi, K.R. Patel, O. Rosti, A. Smogorzewska, D. Kutler. The role of bone marrow transplantation in patients with Fanconi anemia and head and neck squamous cell carcinoma receiving radiotherapy: An examination of the International Fanconi Anemia (IFAR) Registry [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr B23.

Phase 1 Study of Decitabine and Vorinostat Followed By Fludarabine, Cytarabine and G-CSF (FLAG) in Children, Adolescents and Young Adults with Relapsed/Refractory AML: Report from the Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) Consortium

Introduction: Despite progress in the treatment of acute myeloid leukemia (AML) over the past few decades, long-term survival of children, adolescents and young adults remains poor. Most treatment failure is secondary to the development of chemotherapy resistance resulting in relapsed or refractory disease. Epigenetic changes in leukemia cells, such as DNA methylation and/or histone acetylation, can lead to alterations in gene expression thereby causing resistance to chemotherapeutic agents. These epigenetic changes are potentially reversible with agents that demethylate DNA and/or inhibit histone deacetylation which ultimately leads to restoration of normal gene expression and chemosensitivity. We are reporting an ongoing phase I trial of decitabine and vorinostat, two epigenetic modifying agents, followed by chemotherapy in children, adolescents and young adults with relapsed or refractory AML. Methods: T2016-003 is a phase I study that was developed and activated in the TACL consortium in July 2017 for patients 1 to 25 years of age with relapsed or refractory AML. The study followed a standard 3 + 3 phase I cohort escalation design. Three dose levels of decitabine were investigated: dose level 1 (7.5 mg/m2); dose level 2 (10 mg/m2); and dose level 3 (15 mg/m2). Patients received decitabine (at assigned dose level) and vorinostat (age &amp;lt;18 years, 180 mg/m2 once daily; &amp;gt;18 years, 200 mg twice daily) days 1 to 5 followed by fludarabine (30 mg/m2, days 6 to 10), cytarabine (2000 mg/m2, days 6 to 10) and granulocyte colony stimulating factor (G-CSF) (5 μ/kg/dose, days 5 until neutrophil recovery) (FLAG). Intrathecal therapy was given up to 72 hours prior to the initial doses of decitabine/vorinostat, with additional intrathecal therapy for central nervous system disease. Patients could receive up to two cycles of therapy. End of course evaluation by bone marrow minimal residual disease (MRD) testing using flow cytometry was performed between days 35 and 42 or upon adequate blood count recovery. Results: Twenty-five patients have enrolled to date with 24 evaluable for dose limiting toxicity (DLT) and response. Median age was 7 (range, 1 to 20) years. Fourteen patients (58.3%) had relapsed after a prior bone marrow transplant and 7 (29.2%) had refractory disease at time of enrollment. There were no dose limiting toxicities at dose level 1 (n=3, 7.5 mg/m2) or 2 (n=3, 10 mg/m2) of decitabine. However, at dose level 3 (n=12, 15 mg/m2), 3 subjects reported Grade 4 invasive fungal infection (Aspergillus terreus, Candida parapsilosis and Rhizomucor pusillus) leading to de-escalation of decitabine to dose level 2. The study continued dose expansion at dose level 2 without DLT, enrolling 7 additional patients. Twenty-two subjects have completed the study and are evaluable for response. Responses were noted at all dose levels. Eight subjects (36.4%) achieved a complete response (CR) or complete response with incomplete hematologic recovery (CRi). Five of the 8 subjects who achieved a CR/CRi were also negative for MRD. Eight subjects had known epigenetic lesions (i.e. KMT2Ar, CEBPα, IDH2) with 6 (75%) achieving a CR, 4 of whom (66.7%) were also MRD negative. Conclusion: Overall, we identified decitabine (10 mg/m2) in combination with vorinostat and followed by FLAG chemotherapy to be well-tolerated and an effective regimen in pediatric patients with relapsed AML, particularly in subjects with known epigenetic lesions. The study continues to enroll at dose level 2 of decitabine for a total accrual goal of 33 subjects. Correlative analysis of peripheral blood and bone marrow investigating methylation, histone acetylation and gene expression is ongoing. Disclosures Burke: Amgen, Inc.: Consultancy, Speakers Bureau.

Haploidentical BMT Using Fully Myeloablative Conditioning, T Cell Replete Bone Marrow Grafts, and Post-Transplant Cyclophosphamide (PT/Cy) Has Limited Toxicity and Promising Efficacy in the First Prospective Multicenter Trial for Pediatric, Adolescent, and Young Adult Patients with High Risk Acute Leukemias and Myelodysplastic Syndrome

Promising results have been reported for patients with high-risk hematologic malignancies undergoing T-cell-replete myeloablative bone marrow transplant (BMT) from HLA-haploidentical donors with post-transplantation cyclophosphamide (PT/Cy). Here, we report results from the first prospective multicenter pilot trial in the Pediatric Blood and Marrow Transplant Consortium (PBMTC) for pediatric, adolescent, and young adult patients with high risk acute leukemias and myelodysplastic syndrome (MDS) in the US and Canada. Nine centers transplanted 32 patients with acute leukemias or MDS in complete remission (CR) who received myeloablative conditioning consisting of IV Busulfan (pharmacokinetically adjusted) and Cyclophosphamide (Cy, 50 mg/kg/day) days –2 and –1 except for patients with acute lymphocytic leukemia who received Cy (50 mg/kg/day x 2) and total body irradiation (1200cGy). T-cell-replete bone marrow from haploidentical related donors was used for all patients. Postgrafting immunosuppression consisted of Cy (50 mg/kg/day) days 3 and 4, followed by mycophenolate mofetil for 30 days and tacrolimus for 90-180 days. Median age of patients was 12y (range, 1-23) and donors was 35y (range, 4-53). Diagnoses included AML (CR1 = 7, CR2 = 6), ALL (CR1 = 8, CR2 = 5), mixed lineage leukemia (1), and MDS (5). One patient had received a prior BMT. Donor engraftment occurred in 27/32 (84%). Primary graft failures included 3 patients with MDS and 2 with AML (CR1 = 1, CR2 = 1); three of these patients had received suboptimal bone marrow grafts (TNC/kg ≤2e8) and all successfully engrafted after second transplants. Median time to neutrophils >500/μL was 22 days and platelets >20,000/μL was 21 days. Transplant related mortality (TRM) at 180 days, our primary objective, was 0%. Cumulative incidence of acute GVHD grades II-IV at Day 100 was 13%. No patients developed severe acute GVHD grades III-IV. The cumulative incidence of mod-severe chronic GVHD at 1 year was 4%. The cumulative incidence of relapse at 1y was 32%. With a median follow-up of surviving patients of 477 days (range, 180-1127), actuarial overall survival is 77% at 1y. With a median follow-up of event-free patients of 451 days (180-1127), actuarial event-free survival is 68% at 1y. For this first reported multicenter pediatric myeloablative HLA-haploidentical HSCT for high-risk leukemias and MDS with T-cell replete bone marrow and PT/Cy, we have demonstrated a 0% TRM, low cumulative incidences of acute and chronic GVHD, and favorable rates of relapse and survival. Further investigation as to potential reasons for graft failure and consideration of any changes needed to ensure engraftment for certain disease groups are underway. A larger trial comparing haploidentical BMT with other alternative donor sources is in development.

Impact of Newer Agents on Progression Free Survival of Multiple Myeloma in the 2nd 3rd and 4th Line Setting- a Systematic Review

Background: Multiple Myeloma (MM) remains incurable. Majority of the patients ultimately relapse with a lower median event free survival after each successive line of therapy. For newly diagnosed MM patients, the median progression free survival (PFS) has improved drastically with the advent of novel agents. Aim of our review is to discuss median PFSnwith novel agents in the 2nd 3rd and 4th line of treatment in MM.Methods: A comprehensive literature search was done in accordance with the PRISMA guidelines from Jan 1st 2010 to May 30th 2018 using the following 4 databases: PubMed/ Medline, Elsevier/Embase, Wiley/Cochrane and clinicaltrials.gov. Inclusion criteria consisted of all prospective clinical trials that a) included patients with 1-3 prior lines of therapies b) received novel therapeutic agents as an intervention c) outcome was reported as median PFS. We excluded case series, retrospective/observational studies, systematic reviews/meta-analysis. We identified 4777 records through initial database search. After removing duplicates and further screening, 59 full-text articles were assessed for eligibility. 50 articles were subsequently excluded with reason and 9 articles constituting 4937 patients were selected for data extraction and final analysis.Result In a randomized clinical trial (RCT) by Dimopolous et al (2017), 396 patients (median age: 64) in the carfilzomib, lenalidomide and dexamethasone (KRD) arm had median PFS of 26.3 m. In comparison, 396 patients in the control group (median age: 65) that received RD regimen had a median PFS of 17.6 m. Percentage of patients with prior bone marrow transplant (BMT) and high-risk (HR) cytogenetics was 54.8% and 12.1% respectively in the KRD regimen and 57.8% and 13.1% respectively in the RD regimen. The median prior number of therapies was 2 in each group. In the trial by Avet-Loiseau et al 2017, patients in the Ixazomib-RD arm (n=360; HR cytogenetics=21%) had a median PFS of 20.6m as compared to 14.7 m in the control group (RD) arm (n=362; HR cytogenetics=17%). Median prior number of therapies was 2 in each group and 59% and 57% of the patients had prior BMT respectively. Lonial et al (2015) showed that the group (n=321; median age 67) that received elotuzumab-RD regimen had median PFS of 19.4m compared to 14.5m in the control group (n=325; median age 66) that received RD regimen. Prior median therapies were 2 in each arm and BMT was done in 52% and 57% of the patients respectively. A RCT of two drug regimen by Chang et al (2017) showed that patients (n= 464) who received KD had a higher median PFS (18.7m) as compared to patients (n= 465) who received bortezomib(V)-D (9.4 m). KD arm had 37.2% patients with prior BMT as compared to 49.6% in the VD arm whereas the median prior number of therapies was 2 in each arm. HR cytogenetics were present in 21% and 24% respectively. In the trial by Orlowski et al (2015), there was no improvement in the median PFS with the addition of Siltuximab to V as compared to V alone. Similarly, no significant improvement in median PFS was noted by Dimopolus et al (2017) in the combination regimen of Vorinostat-V as compared to placebo-V. In the trial by white et al (2017), the median PFS was 6.2 with bevacizumab-V as compared to 5.1m with placebo-V. In a trial by Richardson et al (2016), Panobinostat-VD had a median PFS of 11.99 which was higher than 8.08 with placebo-VD.Conclusion: Regimen consisting of KRD has the highest median PFS in MM patients with multiple prior lines of therapy followed by IRD based regimen. Limitations of our analysis include a heterogeneous patient population and exclusion of data with daratumumab based regimen because of unavailability of median PFS specifically in the 2nd 3rd and 4th line setting in the published clinical trials. DisclosuresNo relevant conflicts of interest to declare.

Addressing the Adequacy of Current MPN Pain Management Strategies: An International Survey of 502 Patients By the MPN Quality of Life Study Group

Introduction:MPN-related pain, including abdominal discomfort (53.2%), and bone pain (48.5%), is a prevalent complaint within the disorder and is associated with impaired patient quality of life, reduction in most functional domains and overall poor prognosis. Non-targeted treatments for MPN disorders have been previously shown to provide little symptomatic relief for MPN pain. To date, little is known about patient viewpoints on MPN pain, its relationship to other chronic pain syndromes and the impact of pharmacologic and non-pharmacologic pain therapies. In this study, we performed an international survey of MPN patients to better understand the prevalence and management of MPN pain.Methods:This study was performed by the MPN Quality of Life Study Group. A survey was designed by a team of MPN investigators experienced with MPN symptomatology. Survey content included the Barriers Questionnaire II (BQII), a 27-item survey validated to assess patient belief barriers to optimal management of cancer pain measured on a 0 (do not agree at all) to 5 (agree very much) scale (Pain. 2002 Oct;99(3):385-96.). Patients also completed the MPN-10, a 10-item survey of MPN symptoms completed on a 0 (absent) to 10 (worst imaginable) scale (Blood. 2011 Jul 14;118(2):401-8). The survey was posted on high-traffic MPN-related webpages focused on patient education and advocacy (MPN Forum, MPN Net, MPN Research Foundation, MPN Voice) for a total of 28 days. Survey questions evaluated patient demographics, pain histories, current and prior treatment strategies, as well as satisfaction with and barriers to available treatment options.Results:DemographicsA total of 502 MPN patients (MF 26.9%, PV 44.2%, ET 28.9%) completed the survey. Patients were of expected mean age (60.5 years) and primarily female (74.9%). Most were from the United States (66.7%) and primarily English speaking (92.2%). Patients described being diagnosed with their MPN 3 to 10 years (35.4%) or >10 years ago (30.8%). Splenic enlargement was vocalized by 36.5% of patients and few patients had had a known history of blood clots (25.4%), severe bleeding (13.3%), conversion to acute leukemia (0.4%) or prior bone marrow transplant (1.4%). Patients described a treatment history of a variety of MPN therapies including aspirin (82.7%), hydroxyurea (60.6%), phlebotomy (40.6%), ruxolitinib (25.9%), interferon (18.5%), anagrelide (17.3%), active clinical trial (5.0%) and radiation treatment (0.4%).Pain Severity, Prevalence and TreatmentsAmong surveyed patients, the MPN-10 mean was 28.3. Mean individual symptom scores and prevalence were 3.1 and 65.6% for abdominal discomfort and 3.0 and 60.4% for bone pain, respectively indicating a low to moderate symptom burden. Most patients had no prior history of chronic pain prior to their MPN diagnosis (47.1%), with chronic abdominal pain and chronic bone/muscle pain noted prior to MPN development in 5.6% and 20.8% of patients, respectively. Most patients felt that their chronic pain has either stayed the same (26.2%), worsened (28.3%) or significantly worsened (14.5%) since their MPN diagnosis. Many patients found pharmacologic and non-pharmacological therapies efficacious for individual pain symptoms, and 42.1% described regularly taking medication to control their pain (Table 1).Barriers to Pain ManagementOverall, 42.3% of MPN patients reported being unsatisfied with their current pain management plan. Despite this, only 43.5% of patients stated that their MPN providers discussed pain during office visits. Palliative Care (3.1%) and Pain Management (7.3%) were infrequently engaged. On the BQII, patients described being confident that cancer can cause pain (mean 4.2, SD 1.1) but did not necessarily expect to have pain following their MPN diagnosis (mean 2.2, SD 1.8).ConclusionChronic pain (abdominal, bone) is a prevalent and undermanaged feature of MPN disorders. Chronic non-MPN pain is further complicated by the development of the disorder. Many MPN patients lack understanding on its prevalence and furthermore feel ill-equipped to manage it. Patients have, however, found symptomatic benefit from various pharmacological and non-pharmacological treatment modalities that require further exploration. Results from this study suggest MPN patients should be assessed regularly for pain and offered early referral to specialized services for evaluation, source identification and treatment. [Display omitted] DisclosuresScherber:Incyte: Consultancy; Orphan Pharmaceuticals: Honoraria. Mesa:Ariad: Consultancy; Galena: Consultancy; CTI: Research Funding; Incyte: Research Funding; Promedior: Research Funding; Gilead: Research Funding; Novartis: Consultancy; Celgene: Research Funding. Dueck:Bayer: Employment; Pfizer: Honoraria; Phytogine: Employment. Palmer:Novartis: Research Funding.

Irradiated haploidentical donor leukocyte infusions as an adoptive immunotherapy strategy to induce host-versus-tumor effects.

Previous research has shown that irradiated splenocytes preserve the antitumor effect and induce relatively weaker graft-versus-host disease in parent C57BL/6~CB6F1 transplantation. The present study was designed to investigate the antitumor effect of 5-Gy-irradiated haploidentical donor leukocyte infusions (DLI) without prior bone marrow transplantation and the possibly involved mechanism in (H-2d/k)~(H-2b/d) infusion model systems. Hepa 1-6 tumor-bearing mice were used to evaluate the antitumor effect and the possible mechanism of irradiated haploidentical DLI treatment. Changes in tumor volume, lymphocyte proliferation and cytotoxicity, IFN-gamma and IL-2 secretion and donor cell survival in vivo were analyzed. After irradiated haploidentical DLI treatment of the poorly immunogeneic Hepa 1-6 tumor mouse model, the donor cells were rejected and disappeared within 4 days. Surprisingly, an antitumor response was still observed. The infusion treatment effectively inhibited tumor growth and prolonged the survival of recipients, and this effect could be enhanced by combined treatment with cyclophosphamide and impaired by deleting donor-derived T cells. Moreover, the infusion treatment increased the levels of type 1 cytokines including IFN-gamma and IL-2, and enhanced the proliferation of lymphocyte subsets, particularly CD8 + T and NK cells. Specifically, multiple infusions proved to enhance the antitumor effect without inducing graft-versus-host disease. As an adoptive therapy, irradiated haploidentical DLI without bone marrow transplantation might be a promising and safe treatment for cancer.

A novel explanation of corneal clouding in a bone marrow transplant-treated patient with Hurler syndrome

One common complication of mucopolysaccharidosis I-Hurler (MPS1-H) is corneal clouding, which occurs despite current treatments, including bone marrow transplantation. Human corneas were obtained from a 14 year old subject with MPS1-H and visual disability from progressive corneal clouding despite a prior bone marrow transplant at age 2. This was compared to a cornea from a 17 year old donated to our eye bank after his accidental death. The corneas were analyzed microscopically after staining with Alcian blue, antibodies to collagen I, IV, VI, and α-smooth muscle actin. Differences in levels of expression of the indicated molecules were assessed. Corneas from Hurler and control mice were examined similarly to determine potential mechanistic overlap. The MPS1-H subject cornea showed elevations in mucopolysaccharide deposition. The MPS1-H and Hurler mice corneas showed increased and disorganized expression of collagen I and IV relative to the control corneas. The MPS1-H corneas also showed increased and disordered expression of collagen VI. Positive expression of α-smooth muscle actin indicated myofibroblast conversion within the MPS1-H cornea in both the patient and mutant mouse material compared to normal human and control mouse cornea. Increased deposition of collagens and smooth muscle actin correlate with corneal clouding, providing a potential mechanism for corneal clouding despite bone marrow transplantation in MPS1-H patients. It might be possible to prevent or slow the onset of corneal clouding by treating the cornea with drugs known to prevent myofibroblast conversion.

Clinical Results in Heavily Pre-Treated, Drug Refractory Hematologic Malignancies Using Chemotherapy and Targeted Agents Selected By Ex Vivo Analysis of Programmed Cell Death (EVA/PCD)

▪Introduction: The treatment of human hematologic malignancies has rapidly advanced through the application of genomic platforms that have identified drug-able targets and companion diagnostics (e.g. BCR-ABL, IDH-1) and added new classes of targeted agents to the established compendium of cytotoxics. Despite these advances, the complexity, redundancy and promiscuity of cellular transformation remain incompletely understood at the molecular level. This has led to a renewed interest in whole cell experimental models for drug discovery. Laboratory platforms that measure cellular response to cytotoxic insult at the phenotypic level have been shown to correlate significantly with clinical response, and have the capacity to provide insights into chemotherapy selection and drug development. The Ex Vivo Analysis of Programmed Cell Death (EVA/PCD) uses metabolic and morphologic features of drug induced cell death to measure both cytotoxic and targeted drug effects in human primary cultures. We applied EVA/PCD in 20 heavily pre-treated, drug refractory patients from the Hospital Israelita Albert Einstein (HIAE) in Sao Paulo - Brazil.Methods: Peripheral blood, node biopsy or bone marrow aspirates were submitted by overnight courier. Cells isolated by density centrifugation were evaluated by dose response curves that were interpolated to provide LC50 values for comparison with our databases by Z-score. Patients with Acute Lymphoblastic Leukemia (ALL, N=5) , Acute Myeloid Leukemia (AML, N=6), Non-Hodgkin Lymphoma (NHL, N=4) or Multiple Myeloma (MM, N=4) had received a mean of 5, median of 4 (range 1-8) prior therapies, 7 with prior bone marrow transplantation (BMT).Results: of 20 specimens, 16 (80%) provided viable tumor for EVA/PCD. A mean of 8, median of 7(range 3-22) cytotoxics and a mean 7, median of 5(range 1-20) targeted agents were evaluated. Findings were reported by day 7. Nine of 16 patients were treatment candidates, with 5 lost to follow up, 3 dying of sepsis before evaluation and 1 achieving complete remission (CR) with radiation plus Rituximab. Of 7 patients who received assay directed therapy there were 3 CR (43%), 2 partial responses (PR: 28%) and 2 progressive disease (PD: 29%) for an overall response rate of 71%.Conclusion: These results establish the feasibility of laboratory directed therapy in heavily pre-treated patients, with 80% of submitted samples providing actionable results. Although the extremely advanced state of these patients limited the capacity to undergo treatment in some cases, the achievement of CR's and PR's in this drug refractory cohort is of interest. Clinical responses by disease, treatment history and drugs received will be reported. Studies correlating molecular profiles with phenotypic analyses are currently under development. DisclosuresEvans:Rational Therapeutics: Employment. Nagourney:Rational Therapeutics: Employment.

Randomized Phase II Trial of Timed Sequential Cytosine Arabinoside with and without the CHK1 Inhibitor MK-8876 in Adults with Relapsed and Refractory Acute Myelogenous Leukemia

Background: Cytosine arabinoside (ara-C) remains the backbone of most regimens for the treatment of AML. The incorporation of ara-C into DNA activates checkpoint kinase 1 (Chk1) causing replication fork slowing, the accumulation of cells in S phase, and diminished ara-C cytotoxicity. The selective Chk1 inhibitor MK-8776 abrogates ara-C-induced S-phase arrest, thereby enhancing ara-C-induced apoptosis in vitro.1 A phase I trial demonstrated the safety of MK-8876 in combination with infusional ara-C and correlative studies demonstrated increased ara-C-induced H2Ax phosphorylation in AML cells, consistent with unrepaired DNA damage.2 Herein, we report data from a phase II trial comparing ara-C plus MK8876 with ara-C alone.Methods: Patients with relapsed or refractory AML were randomized to receive either ara-C 2 gm/m2 via continuous infusion (CIV) over 72 hours on days 1 and 10 with MK-8776 100 mg flat dose infused over 30 minutes on days 2, 3, 11, and 12 (combo); or ara-C alone on the same schedule (control). The primary end point was response rate (CR+CRi). Adverse events (AEs) for all patients were reported according to the NCI-CTCAE version 4.0. Correlative studies were performed on blood and marrow samples collected prior to treatment on days 1, 2 and 3 and at one hour after MK-8776 infusion (PB only). Marrow and circulating blasts were analyzed using semi-quantitative flow cytometric determinations of blast cell gH2AX expression, a marker of DNA damage.Results: Thirty-two patients were treated at 4 sites with 14 assigned to the combo arm and 18 to the control arm. The study was stopped early due to lack of drug availability. The median age was 60 (range 29-72) and 17 (53%) were male. Nine (28%) had refractory AML, 16 (50%) were in first relapse, and 7 (22%) were in second relapse. Eleven (34%) had undergone a prior bone marrow transplant (BMT). Risk stratification classified 1 (3%) patient as favorable risk disease, 11 (34%) as intermediate-1, 8 (25%) as intermediate-2, and 11 (34%) as adverse risk.There were 5 (36%) responses (CR/CRi) and 1 (7%) partial response (PR) in the combo arm, and 8 (44%) responses and 1 (6%) PR in the control arm. Median survival did not differ significantly between the two groups (5.9 months in the combo arm vs. 4.2 months in the control arm). Sub-group analysis showed increased responses in the combo arm for the patients in first relapse (50% vs. 40%) and those with a prior BMT (50% vs. 29%). Most non-hematologic grade 3/4 treatment-related AEs were similar in the two groups including febrile neutropenia (64% vs. 61%), infectious complications (50% vs. 50%), and sepsis (21% vs. 17%). Patients in the combo arm experienced more QT prolongation (21% vs. 0%), hypertension (21% vs. 0%), and GI toxicities (21% vs. 0%); while those in the control arm had increased renal (0% vs. 11%) and liver toxicity (7% vs. 17%). Two deaths were attributed to treatment, and both were in the control arm.Eight combo patients had serial PB samples and 2 had serial marrow samples studied by flow cytometry. There was an increase in the percentage of gH2AX+ CD34+ cells on Day 2 directly after MK-8876 infusion (16.9% prior and 36.4% at one hour), which occurred to a lesser extent on Day 3 after MK-8876 infusion (12.7% prior and 15.6% at one hour). Three of eight patients demonstrated a sustained increase in gH2AX+ CD34+ from Day 2 to Day 3, and all three achieved either a PR or CR.Conclusion: This is the first phase II study building on prior work suggesting that inhibition of Chk1 would increase response to ara-C in patients with relapsed or refractory AML. The study confirmed that treatment with the combination is feasible with similar toxicities between the treatment and control groups. The response rates were similar between the two groups with improved responses in patients receiving the combo in first relapse and following BMT. Correlative studies support the finding that responding patients show a sustained increase in DNA damage and this may serve as a biomarker in future studies. Chk1 remains a potential target to improve treatment outcomes with ara-C.