Transplantation for myelofibrosis patients in the ruxolitinib era: a registry study from the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire

In this SFGM-TC registry study, we report the results after stem cell transplantation (HSCT) in 305 myelofibrosis patients, in order to determine potential risk factors associated with outcomes, especially regarding previous treatment with ruxolitinib. A total of 102 patients were transplanted from an HLA-matched-sibling donor (MSD), and 143 patients received ruxolitinib. In contrast with previous studies, our results showed significantly worse outcomes for ruxolitinib patients regarding overall survival (OS) and non-relapse mortality (NRM), especially in the context of unrelated donors (URD). When exploring reasons for potential confounders regarding the ruxolitinib effect, an interaction between the type of donor and the use of ATG was found, therefore subsequent analyses were performed separately for each type of donor. Multivariable analyses did not confirm a significant negative impact of ruxolitinib in transplantation outcomes. In the setting of URD, only age and Fludarabine-Melphalan (FM) conditioning were associated with increased NRM. For MSD, only Karnoksfy <70% was associated with reduced OS. However, a propensity score analysis showed that ruxolitinib had a negative impact on OS but only in non-responding patients, consistent with previous data. To conclude, with all the precautions due to confounders and bias, ruxolitinib itself does not appear to increase mortality after HSCT.

Optimization of universal allogeneic CAR-T cells combining CRISPR and transposon-based technologies for treatment of acute myeloid leukemia

Despite the potential of CAR-T therapies for hematological malignancies, their efficacy in patients with relapse and refractory Acute Myeloid Leukemia has been limited. The aim of our study has been to develop and manufacture a CAR-T cell product that addresses some of the current limitations. We initially compared the phenotype of T cells from AML patients and healthy young and elderly controls. This analysis showed that T cells from AML patients displayed a predominantly effector phenotype, with increased expression of activation (CD69 and HLA-DR) and exhaustion markers (PD1 and LAG3), in contrast to the enriched memory phenotype observed in healthy donors. This differentiated and more exhausted phenotype was also observed, and corroborated by transcriptomic analyses, in CAR-T cells from AML patients engineered with an optimized CAR construct targeting CD33, resulting in a decreased in vivo antitumoral efficacy evaluated in xenograft AML models. To overcome some of these limitations we have combined CRISPR-based genome editing technologies with virus-free gene-transfer strategies using Sleeping Beauty transposons, to generate CAR-T cells depleted of HLA-I and TCR complexes (HLA-IKO/TCRKO CAR-T cells) for allogeneic approaches. Our optimized protocol allows one-step generation of edited CAR-T cells that show a similar phenotypic profile to non-edited CAR-T cells, with equivalent in vitro and in vivo antitumoral efficacy. Moreover, genomic analysis of edited CAR-T cells revealed a safe integration profile of the vector, with no preferences for specific genomic regions, with highly specific editing of the HLA-I and TCR, without significant off-target sites. Finally, the production of edited CAR-T cells at a larger scale allowed the generation and selection of enough HLA-IKO/TCRKO CAR-T cells that would be compatible with clinical applications. In summary, our results demonstrate that CAR-T cells from AML patients, although functional, present phenotypic and functional features that could compromise their antitumoral efficacy, compared to CAR-T cells from healthy donors. The combination of CRISPR technologies with transposon-based delivery strategies allows the generation of HLA-IKO/TCRKO CAR-T cells, compatible with allogeneic approaches, that would represent a promising option for AML treatment.

Biallelic TET2 mutations confer sensitivity to 5'-azacitidine in acute myeloid leukemia

Precision medicine can significantly improve outcomes for patients with cancer, but implementation requires comprehensive characterization of tumor cells to identify therapeutically exploitable vulnerabilities. Here, we describe somatic biallelic TET2 mutations in an elderly patient with acute myeloid leukemia (AML) that was chemoresistant to anthracycline and cytarabine but acutely sensitive to 5'-azacitidine (5'-Aza) hypomethylating monotherapy, resulting in long-term morphological remission. Given the role of TET2 as a regulator of genomic methylation, we hypothesized that mutant TET2 allele dosage affects response to 5'-Aza. Using an isogenic cell model system and an orthotopic mouse xenograft, we demonstrate that biallelic TET2 mutations confer sensitivity to 5'-Aza compared with cells with monoallelic mutations. Our data argue in favor of using hypomethylating agents for chemoresistant disease or as first-line therapy in patients with biallelic TET2-mutated AML and demonstrate the importance of considering mutant allele dosage in the implementation of precision medicine for patients with cancer.

Low rate of infectious enterocolitis in allogeneic stem cell transplant recipients with acute diarrhea: A prospective study by the GETH-TC

Acute diarrhea is a common and debilitating complication in recipients of an allogeneic hematopoietic stem cell transplantation (HCT). In this prospective, observational, and multi-center study we examined all episodes occurring in the first 6 months of 142 consecutive adult patients who underwent a reduced-intensity conditioning (RIC) HCT in 10 Spanish tertiary University Hospitals. Fifty-four patients (38%) developed a total of 75 acute diarrhea episodes. The median time from HCT to the first episode was 38 days (4-157). The main cause of enterocolitis was lower GI-aGVHD (38%), followed by infections (21%) and drug-related toxicity (8%). Causative infectious causes were identified in only 16/75 episodes (21%). C. difficile-related infection (CDI) was the most common infectious agent with an incidence and recurrence of 13% and 2%, respectively. With a median follow-up for survivors of 32 months, the NRM and the overall survival (OS) at 1 year, were 20% (95% C.I.: 14-28%) and 69% (95% C.I.: 61-77%), respectively. Development of enterocolitis was not associated with higher NRM (p = 0.37) or worse OS (p = 0.9). This real-life study confirms that the diagnosis and management of acute diarrhea in the early stages after HCT is challenging. Nosocomial infections, seem to be relatively uncommon, probably due to more rational use of antibiotics.

The transcriptomic landscape of elderly acute myeloid leukemia identifies B7H3 and BANP as a favorable signature in high-risk patients

Acute myeloid leukemia (AML) in the elderly remains a clinical challenge, with a five-year overall survival rate below 10%. The current ELN 2017 genetic risk classification considers cytogenetic and mutational characteristics to stratify fit AML patients into different prognostic groups. However, this classification is not validated for elderly patients treated with a non-intensive approach, and its performance may be suboptimal in this context. Indeed, the transcriptomic landscape of AML in the elderly has been less explored and it might help stratify this group of patients. In the current study, we analyzed the transcriptome of 224 AML patients > 65 years-old at diagnosis treated in the Spanish PETHEMA-FLUGAZA clinical trial in order to identify new prognostic biomarkers in this population. We identified a specific transcriptomic signature for high-risk patients with mutated TP53 or complex karyotype, revealing that low expression of B7H3 gene with high expression of BANP gene identifies a subset of high-risk AML patients surviving more than 12 months. This result was further validated in the BEAT AML cohort. This unique signature highlights the potential of transcriptomics to identify prognostic biomarkers in in elderly AML.

Updates on the Management of Acute Myeloid Leukemia

Acute myeloid leukemia is a heterogeneous disease defined by a large spectrum of genetic aberrations that are potential therapeutic targets. New targeted therapies have changed the landscape for a disease with poor outcomes. They are more effective than standard chemotherapy with a good safety profile. For "fit patients" in first-line, the combination of gemtuzumab ozogamicin or midostaurin with intensive chemotherapy or Vyxeos is now considered the "standard of care" for selected patients. On the other hand, for "unfit patients", azacitidine-venetoclax has been consolidated as a frontline treatment, while other combinations with magrolimab or ivosidenib are in development. Nevertheless, global survival results, especially in relapsed or refractory patients, remain unfavorable. New immunotherapies or targeted therapies, such as Menin inhibitors or sabatolimab, represent an opportunity in this situation. Future directions will probably come from combinations of different targeted therapies ("triplets") and maintenance strategies guided by measurable residual disease.

Explainable artificial intelligence for precision medicine in acute myeloid leukemia

Artificial intelligence (AI) can unveil novel personalized treatments based on drug screening and whole-exome sequencing experiments (WES). However, the concept of “black box” in AI limits the potential of this approach to be translated into the clinical practice. In contrast, explainable AI (XAI) focuses on making AI results understandable to humans. Here, we present a novel XAI method -called multi-dimensional module optimization (MOM)- that associates drug screening with genetic events, while guaranteeing that predictions are interpretable and robust. We applied MOM to an acute myeloid leukemia (AML) cohort of 319 ex-vivo tumor samples with 122 screened drugs and WES. MOM returned a therapeutic strategy based on the FLT3, CBFβ-MYH11, and NRAS status, which predicted AML patient response to Quizartinib, Trametinib, Selumetinib, and Crizotinib. We successfully validated the results in three different large-scale screening experiments. We believe that XAI will help healthcare providers and drug regulators better understand AI medical decisions.

AB0589 TOCILIZUMAB FOR GIANT CELL ARTERITIS: BASELINE AND TWELVE MONTH AUDIT DATA FROM THE UK BRISTOL AND BATH MULTIDISCIPLINARY MEETING

Background

Giant Cell Arteritis (GCA) is a systemic vasculitis involving large and medium-sized blood vessels. Treatment is with high dose glucocorticoids. Steroid-sparing agents and Tocilizumab (TCZ) are used for refractory or relapsing cases. NHS England requires all GCA patients to be discussed in a regional multidisciplinary team meeting (MDT) prior to commencing TCZ. TCZ has only been permitted for a maximum of one year; this time limitation was extended during the Covid-19 pandemic (1). The monthly virtual Bristol and Bath regional MDT started in November 2018.

Objectives

We aimed to review: 1) Baseline data on all patients referred to the Bristol and Bath TCZ for GCA MDT, including demographics, clinical presentation and previous steroid-sparing agents used and 2) 12 month follow up data including number of completions, adverse effects, and flares on treatment.

Methods

The TCZ MDT referral proforma, adapted from the NHS England Blueteq approval form, was reviewed for all patients referred. 12 month follow up data was obtained from clinic letters.

Results

Baseline data

Thirty-eight cases were referred between November 2018 and September 2021. Of these, 31 were approved for TCZ usage; 100% fulfilled the criteria for either refractory (n=11) or relapsing (n=20) disease. Mean age was 74 years and 74.2% were female. Average disease duration was 161.5 days for the refractory and 827.3 days for the relapsing group.

77.4% had cranial GCA, 48.4% had large vessel involvement, 45.2% had visual symptoms and 25.8% had ischaemic visual loss. The positive investigations were PET-CT (48.4%), temporal artery ultrasound (41.9%) and temporal artery biopsy (32.3%).

64.5% had trialled a steroid-sparing agent at time of referral (61.3 % methotrexate, 9.7% azathioprine, 6.5% leflunomide), 35.5% had received intravenous methylprednisolone and 58% were receiving greater than 40mg prednisolone at the time of referral.

Glucocorticoid adverse effects of osteoporosis, weight gain, cataracts and hypertension were each seen in 19.4%; whilst diabetes, neuropsychiatric symptoms and sleep disturbance were each reported in 16.1%.

Those with ocular involvement tended to be referred earlier than those without (478.2 days vs 648.1 days), were referred on higher doses of glucocorticoids (71.4% vs 47.1% on ≥ 40mg) and had less steroid-sparing agents prior to referral.

Follow up data

In December 2021, a follow-up audit revealed 14/31 patients had completed at least 12 months of tocilizumab; 5 of these had had an extension under Covid-19 exceptional guidance (mean duration of 5.2 months). Of the remaining 17: 3 patients had stopped early (1 death, 1 moved away, 1 due to adverse effects of headache and gastro-intestinal side effects), 4 had not started tocilizumab and 10 had not completed 12 months of treatment at that point.

Adverse events in the 14 patients at 12 months included: liver abnormalities (2/14; 14.3%), neutropenia (2/14; 14.3%), thrombocytopaenia (1/14; 7.1%), soft tissue infections (3/14; 21.4%), urinary tract infection (1/14; 7.1%) and lipid derangement (4/14 28.6%). One case of GCA relapse occurred on TCZ (mild headache and raised inflammatory markers settled on small increase in prednisolone). After 12 months, mean prednisolone dose was 3mg (range 0-15mg).

Conclusion

All patients approved for Tocilizumab in the GCA MDT fulfilled NHS England criteria for either relapsing or refractory disease. The majority of cases had cranial disease, but almost half had either ocular or large vessel involvement, reflecting a severe spectrum of disease. Cases showed a high burden of glucocorticoid toxicity. Follow up data suggests that TCZ was effective in allowing glucocorticoid weaning and disease control, but with some adverse effects. Future work to follow up patients after stopping Tocilizumab would be informative, as the twelve month limitation on treatment is likely to be re-instated.

References

[1]https://www.england.nhs.uk/coronavirus/publication/tocilizumab-for-giant-cell-arteritis-gca-during-the-covid-19-pandemic-rps-2007/

Disclosure of Interests

Chandrin N. R. Jayatilleke: None declared, Aishwarya Anilkumar: None declared, Shalini Janagan: None declared, Robert W Marshall: None declared, Sarah Skeoch: None declared, Catherine Guly Grant/research support from: Eli Lilly and Company - paid consultant for a research trial, Fang En Sin: None declared, Keziah Austin: None declared, Laith Al-Sweedan: None declared, Alexandra Bourn: None declared, Lynsey Clarke: None declared, Harsha Gunawardena: None declared, Baashar Boyce: None declared, Sally Knights: None declared, John D Pauling: None declared, Elizabeth Reilly: None declared, Timothy D Reynolds: None declared, Sarah Villar: None declared, Joanna C Robson: None declared

Papillary architecture of the lingual surface in the puma (Puma concolor)

This research presents the first anatomical description of the tongue and lingual papillae of the mountain lion (puma). The tongues of three adult male pumas were used in this study. The tongues were dissected and studied firstly by gross and stereomicroscopy. Samples of each part were processed by study with scanning electron microscopy. The margins of the lingual apex were surrounded by numerous filiform papillae, which had a bulky papillary body and a bifurcated tip. On the dorsal surface of the lingual apex, filiform papillae were remarkably pointed and had many secondary projections, which emerged from the base of the main papilla. In the rostral half of the lingual body, filiform papillae were longer, cylindrical and had blunt tips. On the caudal half of the lingual body, filiform papillae gave place to conical ones exhibiting a pointed tip. The fungiform papillae were scattered on the whole dorsal surface of the tongue. On each lateral half of the tongue, four circumvallate papillae were observed and each circumvallate papilla was surrounded by thick and horseshoe-like annular pad, which were composed by pointed conical papillae on the caudal border of the lingual body. The dorsal surface of the circumvallate papilla was covered by many finger-like protrusion, and the tip of each protrusion had a central orifice. Anatomical distribution of lingual papillae was different to other carnivores and represents the adaptation to the feeding habits of this mammal. General morphology of the lingual structures was similar to those of the tiger.

Modeling cancer driver events in vitro using barrier bypass-clonal expansion assays and massively parallel sequencing

The information on candidate cancer driver alterations available from public databases is often descriptive and of limited mechanistic insight, which poses difficulties for reliable distinction between true driver and passenger events. To address this challenge, we performed in-depth analysis of whole-exome sequencing data from cell lines generated by a barrier bypass-clonal expansion (BBCE) protocol. The employed strategy is based on carcinogen-driven immortalization of primary mouse embryonic fibroblasts and recapitulates early steps of cell transformation. Among the mutated genes were almost 200 COSMIC Cancer Gene Census genes, many of which were recurrently affected in the set of 25 immortalized cell lines. The alterations affected pathways regulating DNA damage response and repair, transcription and chromatin structure, cell cycle and cell death, as well as developmental pathways. The functional impact of the mutations was strongly supported by the manifestation of several known cancer hotspot mutations among the identified alterations. We identified a new set of genes encoding subunits of the BAF chromatin remodeling complex that exhibited Ras-mediated dependence on PRC2 histone methyltransferase activity, a finding that is similar to what has been observed for other BAF subunits in cancer cells. Among the affected BAF complex subunits, we determined Smarcd2 and Smarcc1 as putative driver candidates not yet fully identified by large-scale cancer genome sequencing projects. In addition, Ep400 displayed characteristics of a driver gene in that it showed a mutually exclusive mutation pattern when compared with mutations in the Trrap subunit of the TIP60 complex, both in the cell line panel and in a human tumor data set. We propose that the information generated by deep sequencing of the BBCE cell lines coupled with phenotypic analysis of the mutant cells can yield mechanistic insights into driver events relevant to human cancer development.

[Free circulating DNA as a tool for lung cancer patients management]

Free circulating DNA (cfDNA) has been known for several decades. These small DNA fragments are released into the circulation from nucleated cells through necrosis, apoptosis and/or active secretion. These genomic fragments are mainly constitutional (nucleated blood cell DNA), but in patients with cancer, a fraction comes from tumor cells. Although poorly known in the field of thoracic oncology, quantitative and qualitative analysis of the cDNA is nevertheless of great interest. Total cfDNA concentration appears to be an independent prognostic factor in lung cancer. Although changes in total cfDNA concentration is not informative to assess the effectiveness of chemotherapy, following-up the fraction of mutated genes such as EGFR during therapy with tyrosine kinase inhibitors appears to be particularly promising for the early detection of disease progression. The use of cfDNA as liquid biopsy is also very promising for the non-invasive somatic molecular profile either at baseline either for sampling at follow-up. Thus, cfDNA is a very promising tool in thoracic oncology and its translation into practice should be developed quickly.

Dual therapy based on a ritonavir-boosted protease inhibitor as a novel salvage strategy for HIV-1-infected patients on a failing antiretroviral regimen

OBJECTIVES

To assess the efficacy and safety of dual-antiretroviral therapy containing a ritonavir-boosted protease inhibitor (PI/r) in treatment-experienced patients failing a current antiretroviral regimen.

METHODS

Retrospective analysis of 60 consecutive HIV-1-infected patients who started a dual-antiretroviral rescue regimen containing a PI/r, in three hospitals in Spain. Virological failure was defined as confirmed HIV RNA >50 copies/mL at treatment week 24 or later. The percentage of patients remaining free of therapeutic failure was estimated using the Kaplan-Meier method, by intent-to-treat analysis (missing, changes and virological failure = therapeutic failure).

RESULTS

Median baseline characteristics of patients were: 13 years on antiretroviral therapy (four prior highly active antiretroviral therapy regimens and eight different drugs), 380 CD4 cells/mm(3) and HIV RNA 3.04 log(10) copies/mL. All patients had resistance mutations to at least two drug classes, although only 9.3% had specific mutations to darunavir. A darunavir-based regimen was started in 47 (78.4%) patients, combined with etravirine (26.7%), tenofovir (26.7%) or raltegravir (25%). Three (5%) patients discontinued treatment due to side effects. At the end of follow-up, 86.7% of patients remained free of therapeutic failure; the percentages of patients with no therapeutic failure at treatment weeks 24, 48 and 96 were 96.6% (95% CI, 91.9-101.3); 90.1% (95% CI, 81.9-98.3) and 79.8% (95% CI, 66.1-93.5), respectively.

CONCLUSIONS

Our results suggest that a dual-therapy rescue regimen including a PI/r is convenient, well tolerated and potent enough to achieve persistent viral suppression in selected pre-treated patients with low viral load and few PI resistance mutations.

Possible heterochromatin horizontal spread through non-homologous chromosome associations in pachytene chromocenters of Ctenomys Rodents

Heterochromatin patterns were analyzed in the genus Ctenomys from Uruguay which exhibits high karyotype variability. Different amounts and localizations of heterochromatin were observed in species and populations analyzed. While species as C. rionegrensis presented heterochromatic arms in all the chromosomes of the karyotype, other species like C. torquatus showed only few chromosomes with pericentric heterochromatin. At the pachytene stage, bivalents merge in densely stained chromocenters. We detected in these chromocenters the typical highly repeated DNA of this genus after in situ hybridization, the M31 chromodomain through immunofluorescence as well as dense Giemsa staining after C-banding. In species that present low amounts of heterochromatin, only 1 or 2 chromocenters were observed in which bivalents merge as observed in C. rionegrensis. After BRCA1 immunodetection we observed in early pachytene cells positive spots located over heterochromatic chromocenters that strongly suggest heterochromatic DNA repair. Mechanical stress mainly due to increasing chromatin compactness before metaphase I might be a mechanism to spread heterochromatin between different chromosomes within a karyotype.

TP53, EGFR, and KRAS mutations in relation to VHL inactivation and lifestyle risk factors in renal-cell carcinoma from central and eastern Europe

Renal-cell carcinomas (RCC) are frequent in central and eastern Europe and the reasons remain unclear. Molecular mechanisms, except for VHL, have not been much investigated. We analysed 361 RCCs (334 clear-cell carcinomas) from a multi-centre case-control study for mutations in TP53 (exons 5-9 in the whole series and exons 4 and 10 in a pilot subset of 60 tumours) and a pilot 50 tumours for mutations in EGFR (exons 18-21) or KRAS (codon 12) in relation to VHL status. TP53 mutations were detected in 4% of clear-cell cases, independently of VHL mutations. In non-clear-cell carcinomas, they were detected in 11% of VHL-wild-type tumours and in 0% of tumours with VHL functional mutations. No mutations were found in EGFR or KRAS. We conclude that mutations in TP53, KRAS, or EGFR are not major contributors to the RCC development even in the absence of VHL inactivation. The prevalence of TP53 mutations in relation to VHL status may differ between clear-cell and other renal carcinomas.

[Long-term results of patients with congenital diaphragmatic hernia]

OBJECTIVE

Introduction of advanced therapeutic modalities for diaphragmatic congenital hernia (CDH) has allowed to reach considerable improvements in survival rate. Nevertheless, there are few studies which analyze the clinical evolution of the long-term survivors. The aim of this work is to analyze the outcomes of the patients with CDH in our hospital.

METHODS

Fifty-five neonates with CDH were treated in our center between 1998 and 2005. We included in the study those patients that were alive at the moment of first hospital discharge (72%; n=40 patients). ECMO therapy was needed in 6 of them during neonatal treatment. A descriptive transverse review of the clinical record as well as a telephonic interview to the parents was performed for the respiratory, cardiological, digestive and neurological conditions, following standard diagnostic studies in every case. The mean age of the children in the moment of the study was 4.2 years (1-9).

RESULTS

The 8.3% of the children needed domiciliary oxygen therapy during a maximum of 3 months in all the cases. 22% of the cases suffered from respiratory problems, being bronchiolitis and pneumonia the most frequent diagnoses. Only a patient developed asthma. The gastroesophageal reflux is the most frequent long-term condition (47%), but only 8.3% needs surgical treatment. Regarding to cardiological problems, 14% developed pulmonary hypertension, being slight - moderate in all the cases but in one case who was the only deceased of the series. Regarding to neurological problems only 1 patient developed serious alterations (brain paralysis), having suffered a hemorrhage parenquimatosa during the treatment with ECMO. No other patient presents motor, visual nor auditory alterations in the development, last mild alteration in language (4 patients). Differences do not exist with the group of patients that did not need ECMO during the treatment in cardiological and digestive complications, being higher percentage with respiratory problems.

CONCLUSION

In our sample only 2 patients present serious sequels (5%). Of this preliminary study we can conclude that the comorbility in the CDH is very low having these patient a good development and good quality of life.

Gender and viability selection on morphology in fledgling pied flycatchers

Until recently, analyses of gender-dependent differences in viability selection and the ontogeny of sexual size dimorphism have been plagued by difficulties in determining the sex of nestling birds on the basis of morphology. Recently, this problem was overcome using molecular sex identification to report for the first time body-size-mediated antagonistic selection on the viability of male and female collared flycatchers. We used molecular sex identification to analyse natural selection on fledgling viability, sexual size dimorphism and effects of parasites in relation to gender in a Mediterranean population of the related pied flycatcher Ficedula hypoleuca. There was directional positive selection on fledgling weight but no selection on tarsus length. Fledgling weight was the most important determinant of fledgling survival, with heavier fledglings having increased viability. Although selective trends were of the same sign for both sexes, only among female fledglings were selection differentials and gradients statistically significant. Therefore, similar trends in selection were revealed in analyses of a data set where sex was ignored and in separate analyses using same-sex sibship trait means. Mite nest ectoparasites negatively affected fledgling weight, and the effects were stronger in female than male fledglings. There was no effect of parasitism on the tarsus length in males, as previously reported in retrospective analyses performed without knowledge of sex until recruitment. Overall, selection on fledgling viability on the basis of morphological traits and hatching date was not confounded by an individual's gender.