Identification and targeting of treatment resistant progenitor populations in T-cell Acute Lymphoblastic Leukemia

Refractoriness to initial chemotherapy and relapse after remission are the main obstacles to cure in T-cell Acute Lymphoblastic Leukemia (T-ALL). Biomarker guided risk stratification and targeted therapy have the potential to improve outcomes in high-risk T-ALL; however, cellular and genetic factors contributing to treatment resistance remain unknown. Previous bulk genomic studies in T-ALL have implicated tumor heterogeneity as an unexplored mechanism for treatment failure. To link tumor subpopulations with clinical outcome, we created an atlas of healthy pediatric hematopoiesis and applied single-cell multiomic (CITE-seq/snATAC-seq) analysis to a cohort of 40 cases of T-ALL treated on the Children's Oncology Group AALL0434 clinical trial. The cohort was carefully selected to capture the immunophenotypic diversity of T-ALL, with early T-cell precursor (ETP) and Near/Non-ETP subtypes represented, as well as enriched with both relapsed and treatment refractory cases. Integrated analyses of T-ALL blasts and normal T-cell precursors identified a bone-marrow progenitor-like (BMP-like) leukemia sub-population associated with treatment failure and poor overall survival. The single-cell-derived molecular signature of BMP-like blasts predicted poor outcome across multiple subtypes of T-ALL within two independent patient cohorts using bulk RNA-sequencing data from over 1300 patients. We defined the mutational landscape of BMP-like T-ALL, finding that NOTCH1 mutations additively drive T-ALL blasts away from the BMP-like state. We transcriptionally matched BMP-like blasts to early thymic seeding progenitors that have low NR3C1 expression and high stem cell gene expression, corresponding to a corticosteroid and conventional cytotoxic resistant phenotype we observed in ex vivo drug screening. To identify novel targets for BMP-like blasts, we performed in silico and in vitro drug screening against the BMP-like signature and prioritized BMP-like overexpressed cell-surface (CD44, ITGA4, LGALS1) and intracellular proteins (BCL-2, MCL-1, BTK, NF-κB) as candidates for precision targeted therapy. We established patient derived xenograft models of BMP-high and BMP-low leukemias, which revealed vulnerability of BMP-like blasts to apoptosis-inducing agents, TEC-kinase inhibitors, and proteasome inhibitors. Our study establishes the first multi-omic signatures for rapid risk-stratification and targeted treatment of high-risk T-ALL.

Cytosine base editing enables quadruple-edited allogeneic CART cells for T-ALL

Allogeneic chimeric antigen receptor T-cell (CART) therapies require multiple gene edits to be clinically tractable. Most allogeneic CARTs have been created using gene editing techniques that induce DNA double-stranded breaks (DSBs), resulting in unintended on-target editing outcomes with potentially unforeseen consequences. Cytosine base editors (CBEs) install C•G to T•A point mutations in T cells, with between 90% and 99% efficiency to silence gene expression without creating DSBs, greatly reducing or eliminating undesired editing outcomes following multiplexed editing as compared with clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9). Using CBE, we developed 7CAR8, a CD7-directed allogeneic CART created using 4 simultaneous base edits. We show that CBE, unlike CRISPR-Cas9, does not impact T-cell proliferation, lead to aberrant DNA damage response pathway activation, or result in karyotypic abnormalities following multiplexed editing. We demonstrate 7CAR8 to be highly efficacious against T-cell acute lymphoblastic leukemia (T-ALL) using multiple in vitro and in vivo models. Thus, CBE is a promising technology for applications requiring multiplexed gene editing and can be used to manufacture quadruple-edited 7CAR8 cells, with high potential for clinical translation for relapsed and refractory T-ALL.

AB0980 Hand Osteoarthritis: investigating Pain Effects in a randomised placebo-controlled feasibility study of estrogen-containing therapy (HOPE-e): report on the primary feasibility outcomes

Background

There is an unmet need for new treatments for hand osteoarthritis (OA). Symptomatic hand OA is more common in women and its incidence increases round the age of menopause. Pre-clinical, epidemiological and post hoc studies in Hormone Replacement Therapy (HRT) trials implicate estrogen deficiency as of likely importance in OA aetiopathogenesis. No clinical trials of HRT have been carried out in hand OA to date. The licensed HRT Duavive (conjugated estrogens + SERM bazedoxifene) was selected on its potential for efficacy and tolerability.

Objectives

We set out to determine the feasibility and acceptability of this form of HRT in post-menopausal women with hand OA, to generate proof of concept data and refine methods for a full study.

Methods

ISRCTN12196200. Females aged 40-65 yrs and 1-10yrs after final menstrual period with hand OA fulfilling ACR criteria and 2+ painful hand joints were recruited. Eligibility incorporated best practice for HRT prescription but did not require menopausal symptoms. Recruitment was at 3 sites in primary/secondary care, including directly from the community. Design was parallel group, double-blind 1:1 randomisation of Duavive or placebo, orally once daily for 24 weeks, then weaning for 4 weeks before stopping. Routes and rates of recruitment and the acceptability of randomisation, medication (compliance, retention), and proposed outcomes were measured, and the likelihood of unblinding. Measures related to hand pain and function, menopause symptoms and joint appearance. Patient and Public Involvement actively informed study rationale, design and materials. An end of study questionnaire and 2 participant focus groups provided further acceptability data.

Results

Recruitment was for 12/possible 18 months, interrupted due to COVID-19. Some study procedures were modified to allow reopening whilst collecting all primary outcomes. 434 enquiries/referrals were received, leading to 96 telephone pre-screens, of which 33 gave written informed consent and attended face to face screening. 28/33 screened (85%) were eligible and randomised. The highest number of randomisations was from study web presence (n=7) followed by SMS text from GP surgeries (n=5). Of 401 not proceeding, 250 (62%) were ineligible, most commonly due to contraindicated medication, followed by medical contraindication, whilst 55 (14%) decided not to take part, for reasons including not wanting to take a hormone-based drug or difficulty attending study visits. Retention and compliance were excellent. All 28 participants completed all study follow ups, with only 3 withdrawals from treatment due to AEs, 2 of these at week 24 and all in the placebo arm. There were no serious AEs. High levels of completeness of all study outcome measures were achieved. Bang’s blinding index suggested that participants/investigators were well blinded. There were overall high/good levels of satisfaction with taking part in the study. 26/28 (92%) would recommend taking part to others with hand OA (irrespective of study arm). Many found the flexibility offered by a combination of remote and face to face visits (due to the pandemic) attractive. Additional insights from focus groups were to include hand stiffness as well as pain measures but to reduce the overall number of questions.

Conclusion

Despite COVID-19 and a reduced recruitment period, this study recruited sufficient numbers to assess feasibility outcomes. Randomisation of eligible people and retention rates were high. A mixture of remote and face to face visits due to COVID-19 probably improved recruitment and retention and was supported by participants, who were generally satisfied with the study design and medication. The study provided useful insight and improvements that would be incorporated into a future study. Overall, this feasibility study showed that with clear messaging on eligibility and a defined recruitment strategy, recruitment and retention to a study testing this treatment is possible.

Acknowledgements

This research was funded by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB-PG-0416-20023). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. The study team thank the sites and the participants who made this research possible.

Disclosure of Interests

Jennifer A.E. Williams: None declared, Mae Chester-Jones: None declared, Anne Francis: None declared, Ioana Marian: None declared, Megan Goff: None declared, Gretchen Brewer: None declared, Malvika Gulati: None declared, Lucy Eldridge: None declared, Patrick Julier: None declared, Catherine Minns Lowe: None declared, Vicki Barber: None declared, Victoria Glover: None declared, Charles Mackworth-Young: None declared, Tonia Vincent Consultant of: Pfizer, Grant/research support from: Grant support from Fidia, Biosplice, Novartis, Pfizer as part of their contribution to an international consortium., Sarah E Lamb: None declared, Katy Vincent: None declared, Susan J Dutton: None declared, Fiona E Watt Consultant of: Pfizer, Grant/research support from: Pfizer and from Astellas Pharma (> 3 years ago)

Acute effects of exercise on cerebrovascular response and cognitive performance in individuals with stable coronary heart disease

BACKGROUND

Individuals with coronary heart disease (CHD) exhibit cognitive deficits and cerebrovascular dysfunctions, and are at higher risk of developing dementia. Cognitive function in individuals with CHD has never been studied during acute aerobic exercise. Given the increasing popularity of training at high peak power output (PPO), its impact on cerebrovascular and cognitive functions in individuals with CHD should be further studied.

METHOD

Thirty-eight individuals with CHD and 16 healthy controls completed two exercise bouts at 30% and 70% of their individualized PPO on an ergocycle while performing a cognitive task including non-executive and executive conditions. Variations of oxy- deoxy-hemoglobin, and total hemoglobin concentrations were measured on left prefrontal cortex at both PPO using near-infrared spectroscopy.

RESULTS

Cognitive task performances were equivalent between groups at all intensity levels. Individuals with CHD exhibited larger variation of deoxyhemoglobin in the executive condition and larger variation in total hemoglobin concentration in all task conditions compared to healthy controls at 70% of PPO.

CONCLUSION

Exercising at high intensity seems to have a larger impact on cerebral blood volume in CHD patients compared to healthy age-matched controls. Higher exercise intensity has negative impacts on cerebral blood volume variations during a cognitive task in CHD patients and could potentially lead to other neurocognitive dysfunctions. Other studies are needed to determine if a cognitive task administered during an exercise test could help identify individuals with CHD at higher risk of developing cognitive decline.

Cognitive ageing is premature among a community sample of optimally treated people living with HIV

OBJECTIVES

Evidence of premature cognitive ageing amongst people living with HIV (PLHIV) remains controversial due to previous research limitations including underpowered studies, samples with suboptimal antiretroviral access, varying rate of virological control, high rate of AIDS, over-representation of non-community samples, and inclusion of inappropriate controls. The current study addresses these limitations, while also considering mental health and non-HIV comorbidity burden to determine whether PLHIV showed premature cognitive ageing compared with closely comparable HIV-negative controls.

METHODS

This study enrolled 254 PLHIV [92% on antiretroviral therapy; 84% with HIV RNA < 50 copies/mL; 15% with AIDS) and 72 HIV-negative gay and bisexual men [mean (SD) age = 49 (10.2) years] from a single primary care clinic in Sydney, Australia. Neurocognitive function was evaluated with the Cogstate Computerized Battery (CCB) at baseline and 6 months after. Linear mixed-effects (LME) models examined main and interaction effects of HIV status and chronological age on the CCB demographically uncorrected global neurocognitive z-score (GZS), adjusting for repeated testing, and then adjusting sequentially for HIV disease markers, mental health and comorbidities.

RESULTS

HIV status and age interacted with a lower GZS (β = -0.43, P < 0.05). Higher level of anxiety symptoms (β = -0.11, P < 0.01), historical AIDS (β = -0.12, P < 0.05) and historical HIV brain involvement (β = -0.12, P < 0.05) were associated with lower GZS.

CONCLUSIONS

We found a robust medium-sized premature ageing effect on cognition in a community sample with optimal HIV care. Our study supports routine screening of cognitive and mental health among PLHIV aged ≥ 50 years.

FRI0406 CARTILAGE REPAIR ACTIVITY DURING JOINT-PRESERVING TREATMENT MAY BE ACCOMPANIED BY OSTEOPHYTE FORMATION

Background:

Knee joint distraction (KJD) is a joint-preserving treatment to postpone total knee arthroplasty (TKA) and has shown cartilage repair and clinical improvement in patients with severe knee osteoarthritis (OA), as has high tibial osteotomy (HTO). The observed cartilage repair activity could be related to an increase in transforming growth factor-β1 (TGFβ-1), which increases in the synovial fluid (SF) during KJD treatment.1However, animal and ex vivo human studies have shown that TGFβ-1 also induce formation of osteophytes, generally seen as an OA severity hallmark. Similarly, interleukin-6 (IL-6) was observed to increase in SF during KJD treatment and may also be associated with osteophytosis.

As such, we hypothesized that joint-preserving regenerative treatments demonstrating cartilage repair activity lead to general tissue (re)generation, including osteophytosis.

Objectives:

To analyze osteophytosis after KJD and compare this to HTO and natural progression in knee OA.

Methods:

63 KJD patients were included in several clinical trials, one of which was a randomized controlled trial comparing patients indicated for HTO, but treated with KJD (KJDHTO; n=23) vs. patients treated with HTO (n=46). All patients received standardized radiographs before and one and two years after treatment, used to measure osteophyte size. Only patients with measurements at baseline and two-year follow-up were included. As a control group for natural progression, untreated knee OA patients from Cohort Hip & Cohort Knee (CHECK; n=1002) were studied. Only patients who received a TKA during follow-up were included, using their last two measurements before treatment to reflect natural two-year progression (n=44).

A separate group of 20 patients treated with KJD in regular care underwent SF aspirations before and after treatment, and TGFβ-1 and IL-6 levels were measured by immunoassay (Mesoscale Discovery). Unstandardized radiographs were acquired before and one year after treatment, used to score osteophytes with the revised Altman score, resulting in a 0 (normal) to 12 (severe) whole-joint score. Only patients with radiographs and SF aspirations at both baseline and one-year follow-up were included.

Results:

After two years, both KJD (n=58) and HTO (n=38) patients showed a significant increase in osteophyte size (+6.2mm2 and +7.0mm2 resp.; both p<0.003; figure 1), with no significant differences between the treatments (p>0.38). Untreated CHECK patients who underwent TKA did not show significant two-year osteophyte changes before treatment (+2.1mm2; p=0.207; figure 1) and showed significant differences compared with KJD and HTO groups (both p<0.044). In the KJD SF aspiration group (n=17), the Altman osteophyte score was not different at one year compared to baseline (+0.2 points; p=0.653) and there was no association between baseline biomarker values and the baseline Altman osteophyte score, or between changes in these parameters (all p≥0.28). Trichotomization of patients in groups with a decrease, no change or increase in total Altman osteophyte score indicated that there was a statistically significant difference between the three groups in changes in TGFβ-1 (p=0.044; figure 2A), but not IL-6 (p=0.898; figure 2B).

Conclusion:

After KJD treatment, joint space widening and clinical improvement are accompanied by osteophytosis. Similar results were observed after treatment with HTO, suggesting effects occur in regenerative joint-preserving treatments in general. The increased osteophytosis may be a bystander effect of cartilage repair activity related to intra-articular factors like TGFβ-1 and questions whether osteophytosis should necessarily be considered a hallmark of OA worsening.

References:

[1]Watt et al, Osteoarthritis Cartilage 2020

Disclosure of Interests:

Mylène Jansen: None declared, Simon Mastbergen: None declared, Fiona Watt: None declared, Elske Willemse: None declared, Tonia Vincent Consultant of: Ad hoc consultancy GSK, Mundipharma, UCB, Sander Spruijt Consultant of: Consultancy to Zimmer Biomet Inc., Pieter Emans Shareholder of: Shareholder and cofounder start-up company Chondropeptix, Roel Custers: None declared, Ronald Van Heerwaarden: None declared, Floris Lafeber Shareholder of: Co-founder and shareholder of ArthroSave BV

Exploring functionalized titania for task specific application of efficient separation of trivalent f-block elements

Functionalized titania, obtained by grafting the dipicolinic acid functionality, was explored for task specific application of highly efficient separation of trivalent f-block elements.

Gene expression signature associated with in vitro dexamethasone resistance and post-induction minimal residual disease in pediatric T-cell acute lymphoblastic leukemia

10033

Background: T-cell acute lymphoblastic leukemia (T-ALL) is a genetically heterogeneous disease, which has largely precluded the use of genetic mutations for risk stratification. We hypothesized that despite this heterogeneity, diverse T-ALLs may have functional similarities that underlie patterns of chemotherapy sensitivity. Methods: We used flow cytometry to evaluate in vitro dexamethasone (DEX) sensitivity and baseline expression of signal transduction effectors and BCL2-family proteins in 68 fresh diagnostic T-ALL samples from patients enrolled on the Children’s Oncology Group (COG) trial AALL1231. We also performed RNA-sequencing (RNA-seq) on 40 AALL1231 samples and used hierarchical clustering and linear regression to analyze these and published T-ALL RNA-seq data from COG AALL0434. Comparisons between groups were made using t-tests and Fisher’s exact tests. Results: Of the proteins analyzed, only high BCL2 expression was significantly associated with increased in vitro DEX resistance (p = 0.002). Hierarchical clustering of the AALL1231 RNA-seq data identified two distinct clusters. Cluster 1 was associated with significantly higher BCL2 transcript expression (p = 0.0002) and in vitro DEX resistance (p = 0.04) relative to cluster 2. We defined a gene set consisting of the top 210 differentially expressed genes between these clusters and applied this gene set to the COG AALL0434 cohort. In this analysis, the early T-cell precursor (ETP) and near-ETP samples clustered together (p < 0.0001) in cluster 1 along with 39 of 146 non-ETP samples. Not only did these cluster 1 non-ETP samples have significantly higher BCL2 transcript expression relative to the non-ETP samples in cluster 2 (p < 0.0001), but 54% of these non-ETP samples were minimal residual disease (MRD) positive (≥0.01%) at the end of induction, as opposed to only 16% of the non-ETP samples in cluster 2 (p < 0.0001). Conclusions: Gene expression profiling identifies non-ETP T-ALLs that cluster with ETP/near-ETP T-ALLs and have significantly higher BCL2 expression and increased rates of post-induction MRD.

Optimal positioning of optodes on the scalp for personalized functional near-infrared spectroscopy investigations

BACKGROUND

Application of functional Near InfraRed Spectroscopy (fNIRS) in neurology is still limited as a good optical coupling and optimized optode coverage of specific brain regions remains challenging, notably for prolonged monitoring.

METHODS

We propose to evaluate a new procedure allowing accurate investigation of specific brain regions. The procedure consists in: (i) A priori maximization of spatial sensitivity of fNIRS measurements targeting specific brain regions, while reducing the number of applied optodes in order to decrease installation time and improve subject comfort. (ii) Utilization of a 3D neuronavigation device and usage of collodion to glue optodes on the scalp, ensuring good optical contact for prolonged investigations. (iii) Local reconstruction of the hemodynamic activity along the cortical surface using inverse modelling.

RESULTS

Using realistic simulations, we demonstrated that maps derived from optimal montage acquisitions showed, after reconstruction, spatial resolution only slightly lower to that of ultra high density montages while significantly reducing the number of optodes. The optimal montages provided overall good quantitative accuracy especially at the peak of the spatially reconstructed map. We also evaluated real motor responses in two healthy subjects and obtained reproducible motor responses over different sessions.

COMPARISON WITH EXISTING METHODS

We are among the first to propose a mathematical optimization strategy, allowing high sensitivity measurements.

CONCLUSIONS

Our results support that using personalized optimal montages should allow to conduct accurate fNIRS studies in clinical settings and realistic lifestyle conditions.

Real-time diffraction computed tomography data reduction

Diffraction imaging is an X-ray imaging method which uses the crystallinity information (cell parameter, orientation) as a signal to create an image pixel by pixel: a pencil beam is raster-scanned onto a sample and the (powder) diffraction signal is recorded by a large area detector. With the flux provided by third-generation synchrotrons and the speed of hybrid pixel detectors, the acquisition speed of these experiments is now limited by the transfer rate to the local storage as the data reduction can hardly be performed in real time. This contribution presents the benchmarking of a typical data analysis pipeline for a diffraction imaging experiment like the ones performed at ESRF ID15a and proposes some disruptive techniques to decode CIF binary format images using the computational power of graphics cards to be able to perform data reduction in real time.

Distinctive cutaneous and systemic features associated with specific antimyositis antibodies in adults with dermatomyositis: a prospective multicentric study of 117 patients

BACKGROUND

Identification of myositis-specific autoantibodies (MSAs) for dermatomyositis (DM) could allow the characterization of an antibody-associated clinical phenotype.

OBJECTIVE

We sought to define the clinical phenotype of DM and the risk of cancer, interstitial lung disease (ILD) and calcinosis based on MSA.

METHODS

A 3.5-year multicentre prospective study of adult DM patients was conducted to determine the clinical phenotype associated with MSAs and the presence of cancer, ILD and calcinosis.

RESULTS

MSAs were detected in 47.1% of 117 included patients. Patients with antimelanoma differentiation-associated protein-5 antibodies (13.7%) had significantly more palmar violaceous macules/papules [odds ratio (OR) 9.9], mechanic's hands (OR 8), cutaneous necrosis (OR 3.2), articular involvement (OR 15.2) and a higher risk of ILD (OR 25.3). Patients with antitranscriptional intermediary factor-1 antibodies (11.1%), antinuclear matrix protein-2 antibodies (6.8%) and antiaminoacyl-transfer RNA synthetase (5.1%) had, respectively, significantly more poikiloderma (OR 5.9), calcinosis (OR 9.8) and articular involvement (OR 15.2). Cutaneous necrosis was the only clinical manifestation significantly associated with cancer (OR 3.1).

CONCLUSION

Recognition of the adult DM phenotype associated with MSAs would allow more accurate appraisal of the risk of cancer, ILD and calcinosis.

Comparison of Kaposi Sarcoma Risk in Human Immunodeficiency Virus-Positive Adults Across 5 Continents: A Multiregional Multicohort Study

BACKGROUND

We compared Kaposi sarcoma (KS) risk in adults who started antiretroviral therapy (ART) across the Asia-Pacific, South Africa, Europe, Latin, and North America.

METHODS

We included cohort data of human immunodeficiency virus (HIV)-positive adults who started ART after 1995 within the framework of 2 large collaborations of observational HIV cohorts. We present incidence rates and adjusted hazard ratios (aHRs).

RESULTS

We included 208140 patients from 57 countries. Over a period of 1066572 person-years, 2046 KS cases were diagnosed. KS incidence rates per 100000 person-years were 52 in the Asia-Pacific and ranged between 180 and 280 in the other regions. KS risk was 5 times higher in South African women (aHR, 4.56; 95% confidence intervals [CI], 2.73-7.62) than in their European counterparts, and 2 times higher in South African men (2.21; 1.34-3.63). In Europe, Latin, and North America KS risk was 6 times higher in men who have sex with men (aHR, 5.95; 95% CI, 5.09-6.96) than in women. Comparing patients with current CD4 cell counts ≥700 cells/µL with those whose counts were <50 cells/µL, the KS risk was halved in South Africa (aHR, 0.53; 95% CI, .17-1.63) but reduced by ≥95% in other regions.

CONCLUSIONS

Despite important ART-related declines in KS incidence, men and women in South Africa and men who have sex with men remain at increased KS risk, likely due to high human herpesvirus 8 coinfection rates. Early ART initiation and maintenance of high CD4 cell counts are essential to further reducing KS incidence worldwide, but additional measures might be needed, especially in Southern Africa.

Improving the spatial and statistical accuracy in X-ray Raman scattering based direct tomography

An algorithm to simultaneously increase the spatial and statistical accuracy of X-ray Raman scattering (XRS) based tomographic images is presented. Tomography that utilizes XRS spectroscopy signals as a contrast for the images is a new and promising tool for investigating local atomic structure and chemistry in heterogeneous samples. The algorithm enables the spatial resolution to be increased based on a deconvolution of the optical response function of the spectrometer and, most importantly, it allows for the combination of data collected from multiple analyzers and thus enhances the statistical accuracy of the measured images.

Sirolimus is effective in relapsed/refractory autoimmune cytopenias: results of a prospective multi-institutional trial

Patients with autoimmune multilineage cytopenias are often refractory to standard therapies requiring chronic immunosuppression with medications with limited efficacy and high toxicity. We present data on 30 patients treated on a multicenter prospective clinical trial using sirolimus as monotherapy. All children (N = 12) with autoimmune lymphoproliferative syndrome (ALPS) achieved a durable complete response (CR), including rapid improvement in autoimmune disease, lymphadenopathy, and splenomegaly within 1 to 3 months of starting sirolimus. Double-negative T cells were no longer detectable in most, yet other lymphocyte populations were spared, suggesting a targeted effect of sirolimus. We also treated 12 patients with multilineage cytopenias secondary to common variable immunodeficiency (CVID), Evans syndrome (ES), or systemic lupus erythematosus (SLE), and most achieved a CR (N = 8), although the time to CR was often slower than was seen in ALPS. Six children with single-lineage autoimmune cytopenias were treated and only 2 responded. Sirolimus was well tolerated with very few side effects. All of the responding patients have remained on therapy for over 1 year (median, 2 years; range, 1 to 4.5 years). In summary, sirolimus led to CR and durable responses in a majority of children with refractory multilineage autoimmune cytopenias. The responses seen in ALPS patients were profound, suggesting that sirolimus should be considered as a first-line, steroid-sparing treatment of patients needing chronic therapy. The results in other multilineage autoimmune cytopenia cohorts were encouraging, and sirolimus should be considered in children with SLE, ES, and CVID. This trial was registered at www.clinicaltrials.gov as #NCT00392951.

Chitin-Prussian blue sponges for Cs(I) recovery: from synthesis to application in the treatment of accidental dumping of metal-bearing solutions

Prussian blue (i.e., iron[III] hexacyanoferrate[II], PB) has been synthesized by reaction of iron(III) chloride with potassium hexacyanoferrate and further immobilized in chitosan sponge (cellulose fibers were added in some samples to evaluate their impact on mechanical resistance). The composite was finally re-acetylated to produce a chitin-PB sponge. Experimental conditions such as the freezing temperature, the content of PB, the concentration of the biopolymer and the presence of cellulose fibers have been varied in order to evaluate their effect on the porous structure of the sponge, its water absorption properties and finally its use for cesium(I) recovery. The concept developed with this system consists in the absorption of contaminated water by the composite sponge, the in situ binding of target metal on Prussian blue load and the centrifugation of the material to remove treated water from soaked sponge. This material is supposed to be useful for the fast treatment of accidental dumping of Cs-contaminated water.

Efficacy of JAK/STAT pathway inhibition in murine xenograft models of early T-cell precursor (ETP) acute lymphoblastic leukemia

Early T-cell precursor (ETP) acute lymphoblastic leukemia (ALL) is a recently described subtype of T-ALL characterized by a unique immunophenotype and genomic profile, as well as a high rate of induction failure. Frequent mutations in cytokine receptor and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways led us to hypothesize that ETP-ALL is dependent on JAK/STAT signaling. Here we demonstrate aberrant activation of the JAK/STAT pathway in ETP-ALL blasts relative to non-ETP T-ALL. Moreover, ETP-ALL showed hyperactivation of STAT5 in response to interleukin-7, an effect that was abrogated by the JAK1/2 inhibitor ruxolitinib. In vivo, ruxolitinib displayed activity in 6 of 6 patient-derived murine xenograft models of ETP-ALL, with profound single-agent efficacy in 5 models. Ruxolitinib treatment decreased peripheral blast counts relative to pretreatment levels and compared with control (P < .01) in 5 of 6 ETP-ALL xenografts, with marked reduction in mean splenic blast counts (P < .01) in 6 of 6 samples. Surprisingly, both JAK/STAT pathway activation and ruxolitinib efficacy were independent of the presence of JAK/STAT pathway mutations, raising the possibility that the therapeutic potential of ruxolitinib in ETP-ALL extends beyond those cases with JAK mutations. These findings establish the preclinical in vivo efficacy of ruxolitinib in ETP-ALL, a biologically distinct subtype for which novel therapies are needed.

Abstract 997: Targeting the Jak/Stat signaling pathway is highly effective in xenograft models of early T cell precursor (ETP) acute lymphoblastic leukemia (ALL)

ETP ALL is a recently described subtype of T-ALL with poor prognosis and is defined by a unique immunophenotype, expressing T-lineage and myeloid/early progenitor markers. ETP ALL blasts have a diverse array of genetic alterations without a unifying mutated gene or pathway. A fraction have mutations in genes involved in Jak/Stat signaling, and we hypothesized targeting Jak/Stat may be effective for some ETP ALL patients.

We evaluated Jak/Stat signaling by phosphoflow cytometry and immunoblotting of blasts collected from patients with ETP ALL with and without Jak/Stat pathway mutations and compared them to non-ETP T-ALL blasts. We xenografted blasts from 6 different ETP ALL patient samples with heterogeneous mutations (Table) into immunodeficient NSG mice and tested the in vivo efficacy of the Jak1/2 inhibitor ruxolitinib (rux). Mice were randomized to rux or vehicle after they developed &gt;1% peripheral blood (pb) blasts (cytoCD3+/CD45+) by flow cytometry (FACS). Disease burden was assessed by FACS enumeration of pb blasts weekly and splenic blasts at sacrifice.

We found that the Jak/Stat signaling pathway was dysregulated in ETP ALL samples, including in samples without identifiable mutations in Jak/Stat. ETP ALL blasts had marked increased expression of pSTAT1 (p = 0.01), pSTAT3 (p = 0.01) and pSTAT5 (p = 0.02) when compared to non ETP T-ALL by immunoblot, results confirmed by phosphoflow. All 6 ETP samples had a profound in vivo response to rux; circulating and splenic blasts were markedly reduced in all treated animals compared to controls (Table). The degree of response was comparable to that seen with TKIs in BCR-ABL ALL, using the same xenograft model. These results strongly suggest that ETP ALL blasts may be addicted to Jak/Stat signaling, irrespective of the presence of identifiable Jak/Stat mutations and that clinical trials testing Jak/Stat inhibitors are needed.

Ruxolitinib is active in ETP ALLGenetic alterationAvg splenic blasts in millions. Control vs Rux Treated (p value by 2-tailed t-test)DNM2 m, JAK3 m157 vs 5 (p &lt;0.01)PTPN11 SV124 vs 31 (p &lt;0.01)GATA3 del, JAK1m, SH2B3 SV192 vs 18 (p &lt;0.01)EZH2 m, RUNX1 m, NOTCH1 m, IKZF1m, SUZ12 m, SH2B3 SV452 vs 25 (p &lt;0.01)EED m256 vs 1 (p &lt;0.01)GATA3 m, JAK1 m, PTEN del, RB1 del, CDKN2A/B del332 vs 4 (p &lt;0.01)m = mutation; del = deletion; SV = structural variationPK obtained from mice demonstrated serum levels that correlate with humans treated with drug and that would be expected to target JAK1 and JAK2 but not JAK3.

Citation Format: Shannon L. Maude, Sibasish Dolai, Cristina Delagdo-Martin, Tiffaney Vincent, Alissa Robbins, Arthavan Selvanathan, Theresa Ryan, Stephen P. Hunger, Mignon L. Loh, Charles G. Mullighan, Brent L. Wood, Michelle L. Hermiston, Stephan A. Grupp, Richard B. Lock, David T. Teachey. Targeting the Jak/Stat signaling pathway is highly effective in xenograft models of early T cell precursor (ETP) acute lymphoblastic leukemia (ALL). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 997. doi:10.1158/1538-7445.AM2014-997

[Prevalence of cancer in the Afro-Caribbean population presenting dermatomyositis and anti-synthetase syndrome: a preliminary study conducted at Pointe-à-Pitre University Hospital, 2000-2012]

BACKGROUND

An association with cancer is described in 17-32% of cases of dermatomyositis (DM) and in 5-16% of cases of anti-synthetase syndrome (ASS). The literature contains very few studies involving Afro-Caribbean patients with DM or ASS. The aim of our retrospective study was to determine the prevalence of cancer in a series of patients with DM or ASS at the University Hospital of Pointe-à-Pitre between 1st January 2000 and 31st December 2012. The secondary objective was to review the clinical and laboratory features as well as the course of DM/ASS in these patients.

PATIENTS AND METHODS

The inclusion criteria were as follows: Afro-Caribbean origin; age >15 years; patient living in Guadeloupe; screening for malignancy.

RESULTS

Twenty-two patients were included (15 DM, 7 ASS). Only one case of cancer was diagnosed in the entire study population at a mean follow-up of 6 ± 4 years (prevalence: 6.7%, CI95% [1.7-31.9]). Of the 15 patients presenting DM (sex ratio F/M: 4, mean age: 45 ± 14 years), 6 (40%) had associated connective tissue disease.

CONCLUSION

Our study suggests a weak association between DM and cancer in Afro-Caribbean patients. These results may be explained by the features of the disease seen in these patients (female gender, young age at onset, associated connective tissue disease) and the low prevalence in the Caribbean region of cancers typically associated with DM.

Leukaemia in young children in the vicinity of British nuclear power plants: a case-control study

BACKGROUND

Concern about the risk of leukaemia in children living near nuclear power plants (NPPs) persists. Previous British analyses have been area based and consequently thought to be less effective than case-control studies.

METHODS

Cases of childhood leukaemia and non-Hodgkin lymphoma (LNHL) born and diagnosed in Great Britain between 1962 and 2007, with matched cancer-free controls, were analysed by logistic regression to estimate the risk of residential proximity at birth and diagnosis to the nearest NPP, adjusting for relevant variables.

RESULTS

For 9821 children with LNHL under the age of 5 years, the estimated extra risk associated with residential proximity to an NPP at birth was negative-interpolated Odds Ratio (OR) at 5 km was 0.86 (0.49-1.52). The comparison of 10 618 children with LNHL under five with 16 760 similarly aged children with other cancers also gave a negative estimate of the extra risk of residential proximity at diagnosis-interpolated OR at 5 km was 0.86 (0.62-1.18).

CONCLUSION

Our results show little evidence of an increase in risk of LNHL to children aged under 5 years from living in the vicinity of an NPP. Risk estimates are incompatible with comparable ones published in a recent German case-control study.

Immunological follow-up of patients with neuromyelitis optica: Is there a good biomarker?

A serial assessment of biomarkers related to disease activity could be clinically useful in some autoimmune diseases. Neuromyelitis optica (NMO) is a severe inflammatory disease of the optic nerves and spinal cord that can be associated with lupus erythematosus, Sjögren syndrome or myasthenia gravis. In this review, we discuss the existing data on the use of biomarkers of disease activity in NMO. A specific and pathogenic antibody (Ab) directed against aquaporin 4 (AQP4) was recently discovered in this disease. The relapses were frequently accompanied by a rise and immunosuppressive therapy by a decrease in serum anti-AQP4 Ab concentrations. However, this association is not strong enough to justify treatment changes based only on anti-AQP4 Ab level variations. This parameter might be helpful as a longitudinal biomarker but only if a threshold inducing a relapse and justifying a switch in therapy can be established. A link between disease severity and serum cytotoxicity against AQP4-expressing cells was proposed but has not yet been confirmed. Finally, the assessment of T cell immunity against AQP4 and specific cytokines could be future directions for research.

Targeting JAK1/2 and mTOR in murine xenograft models of Ph-like acute lymphoblastic leukemia

CRLF2 rearrangements, JAK1/2 point mutations, and JAK2 fusion genes have been identified in Philadelphia chromosome (Ph)-like acute lymphoblastic leukemia (ALL), a recently described subtype of pediatric high-risk B-precursor ALL (B-ALL) which exhibits a gene expression profile similar to Ph-positive ALL and has a poor prognosis. Hyperactive JAK/STAT and PI3K/mammalian target of rapamycin (mTOR) signaling is common in this high-risk subset. We, therefore, investigated the efficacy of the JAK inhibitor ruxolitinib and the mTOR inhibitor rapamycin in xenograft models of 8 pediatric B-ALL cases with and without CRLF2 and JAK genomic lesions. Ruxolitinib treatment yielded significantly lower peripheral blast counts compared with vehicle (P < .05) in 6 of 8 human leukemia xenografts and lower splenic blast counts (P < .05) in 8 of 8 samples. Enhanced responses to ruxolitinib were observed in samples harboring JAK-activating lesions and higher levels of STAT5 phosphorylation. Rapamycin controlled leukemia burden in all 8 B-ALL samples. Survival analysis of 2 representative B-ALL xenografts demonstrated prolonged survival with rapamycin treatment compared with vehicle (P < .01). These data demonstrate preclinical in vivo efficacy of ruxolitinib and rapamycin in this high-risk B-ALL subtype, for which novel treatments are urgently needed, and highlight the therapeutic potential of targeted kinase inhibition in Ph-like ALL.

In vivo monitoring of JAK/STAT and PI3K/mTOR signal transduction inhibition in pediatric CRLF2-rearranged acute lymphoblastic leukemia (ALL)

9506

Background: Therapy intensification for children with B-precursor ALL with high-risk genetic lesions has improved relapse-free survival. CRLF2 rearrangements and JAK2 and IL7RA mutations occur in 10-15% of adult and pediatric ALL patients, most of whom relapse. We and others identified aberrant kinase signatures and perturbed JAK/STAT and PI3K/mTOR signal transduction via in vitro studies of CRLF2-rearranged (CRLF2r) ALLs, suggesting the therapeutic relevance of signal transduction inhibitors (STIs). Our creation of CRLF2r ALL xenograft models has enabled rapid preclinical testing of STIs and measurement of in vivo target inhibition. We hypothesized that inhibition of JAK/STAT and PI3K/mTOR phosphosignaling correlates with therapeutic responses in these models. Methods: NOD/SCID/γc-null (NSG) mice well-engrafted with pediatric ALL samples were treated with the JAK inhibitor ruxolitinib, the mTOR inhibitor sirolimus, or vehicle for 72 hours (for signaling response) or 4 weeks (for therapeutic response). Splenocytes were briefly stimulated ex vivo with thymic stromal lymphopoietin (ligand for CRLF2) and stained with human-specific surface and intracellular phosphoantibodies for multi-parameter phosphoflow cytometry analysis. Results: Ruxolitinib-induced inhibition of phospho (p)-JAK2 and pSTAT5 was most pronounced in non-CRLF2r ALLs with novel JAK2-activating BCR-JAK2 and IL7RA/LNK mutations. Sirolimus potently inhibited pS6 and other PI3K/mTOR pathway phosphoproteins in the CRLF2r r ALLs. PSTAT5 and pS6 inhibition correlated with longer-term ruxolitinib- and sirolimus-induced decreases in ALL cell burden, demonstrating therapeutic responses to STIs. Conclusions: Ruxolitinib inhibited JAK/STAT phosphosignaling and markedly decreased leukemic burden in the JAK2-activating BCR-JAK2 and IL7RA/LNK mutant ALL xenografts. Sirolimus potently inhibited PI3K/mTOR (as well as some JAK/STAT) phosphosignaling and had greater therapeutic efficacy than ruxolitinib in the CRLF2r ALLs. The safety of ruxolitinib and of temsirolimus with cytotoxic chemotherapy are currently being established in Children’s Oncology Group Phase I trials.

MicroRNA biogenesis is required for Myc-induced B-cell lymphoma development and survival

Many tumor cells express globally reduced levels of microRNAs (miRNA), suggesting that decreased miRNA expression in premalignant cells contributes to their tumorigenic phenotype. In support of this, Dicer, an RNase III-like enzyme that controls the maturation of miRNA, was recently shown to function as a haploinsufficient tumor suppressor in nonhematopoietic cells. Because the Myc oncoprotein, a critical inducer of B-cell lymphomas, was reported to suppress the expression of multiple miRNAs in lymphoma cells, it was presumed that a deficiency of Dicer and subsequent loss of miRNA maturation would accelerate Myc-induced lymphoma development. We report here that, surprisingly, a haploinsufficiency of Dicer in B cells failed to promote B-cell malignancy or accelerate Myc-induced B-cell lymphomagenesis in mice. Moreover, deletion of Dicer in B cells of CD19-cre(+)/Emicro-myc mice significantly inhibited lymphomagenesis, and all lymphomas that did arise in these mice lacked functional Cre expression and retained at least one functional Dicer allele. Uncharacteristically, the lymphomas that frequently developed in the CD19-cre(+)/Dicer(fl/fl)/Emicro-myc mice were of very early precursor B-cell origin, a stage of B-cell development prior to Cre expression. Therefore, loss of Dicer function was not advantageous for lymphomagenesis, but rather, Dicer ablation was strongly selected against during Myc-induced B-cell lymphoma development. Moreover, deletion of Dicer in established B-cell lymphomas resulted in apoptosis, revealing that Dicer is required for B-cell lymphoma survival. Thus, Dicer does not function as a haploinsufficient tumor suppressor in B cells and is required for B-cell lymphoma development and survival.

Perinatal characteristics and outcome of preterm singleton, twin and triplet infants in NSW and the ACT, Australia (1994-2005)

OBJECTIVE

To compare the perinatal characteristics, neonatal morbidity and mortality of preterm singletons, twins and triplets born at 22-31 weeks' gestation and admitted to neonatal intensive care units (NICU) in New South Wales and Australian Capital Territory between 1994 and 2005.

METHODS

Perinatal characteristics and neonatal outcome data were obtained from the regional NICUS data collection to test for a priori hypothesis. The 10 068 very premature infants studied included 7304 (72.5%) singletons, 2444 (24.2%) twins and 320 (3.2%) triplets.

RESULTS

Assisted conception was associated with a higher maternal age and increased twins and triplets admissions into NICU than spontaneous conceptions (twins OR 6.9, 95% CI 6.1 to 8.0; and triplets OR 35.6, 95% CI 27.6 to 45.8). Major neonatal morbidities were similar between the three groups of singletons, twins or triplets. While twins of 22-27 weeks' gestation (adjusted OR 1.39, 95% CI 1.12 to 1.72) had higher mortality compared with singletons, mortality only diverged below 24 weeks' gestation. Mortality was predicted by decreasing gestational age, male gender and lack of antenatal steroids, whereas assisted conception was protective against mortality (adjusted OR 0.69, 95% CI 0.57 to 0.86).

CONCLUSIONS

Assisted conception contributed to higher very premature NICU admissions of twins and triplets. Preterm twins at the very extreme of viability had higher mortality compared with singletons. The protective effect of assisted conception against mortality requires further research.