Zeitschriftenartikel zum Thema „Sandbox evasion“

Malware analysis is fundamental for defending against prevalent cyber security threats and requires a means to deploy and study behavioural software traits as more sophisticated malware is developed. Traditionally, virtual machines are used to provide an environment that is isolated from production systems so as to not cause any adverse impact on existing infrastructure. Malware developers are fully aware of this and so will often develop evasion techniques to avoid detection within sandbox environments. In this paper, we conduct an investigation of anti-evasion malware triggers for uncovering malware that may attempt to conceal itself when deployed in a traditional sandbox environment. To facilitate our investigation, we developed a tool called MORRIGU that couples together both automated and human-driven analysis for systematic testing of anti-evasion methods using dynamic sandbox reconfiguration techniques. This is further supported by visualisation methods for performing comparative analysis of system activity when malware is deployed under different sandbox configurations. Our study reveals a variety of anti-evasion traits that are shared amongst different malware families, such as sandbox “wear-and-tear”, and Reverse Turing Tests (RTT), as well as more sophisticated malware samples that require multiple anti-evasion checks to be deployed. We also perform a comparative study using Cuckoo sandbox to demonstrate the limitations of adopting only automated analysis tools, to justify the exploratory analysis provided by MORRIGU. By adopting a clearer systematic process for uncovering anti-evasion malware triggers, as supported by tools like MORRIGU, this study helps to further the research of evasive malware analysis so that we can better defend against such future attacks.

Advanced persistent threats (APT) are major threats in the field of system and network security. They are extremely stealthy and use advanced evasion techniques like packing and behaviour obfuscation to hide their malicious behaviour and evade the detection methods. Existing behavior-based detection technique fails to detect the APTs due to its high persistence mechanism and sophisticated code nature. Hence, a novel hybrid analysis technique using Behavior based Sandboxing approach is proposed. The proposed technique consists of four phases namely, Static, Dynamic, Memory and System state analysis. Initially, static analysis is performed on the sample which involves packer detection and signature verification. If the sample is found stealthy and remains undetected, then it is executed inside a sandbox environment to analyze its behavior. Further, memory analysis is performed to extract memory artefacts of the current system state. Finally, system state analysis is performed by correlating clean system state and infected system state to determine whether the system is compromised

Recent work has shown that adversarial Windows malware samples—referred to as adversarial EXE mples in this article—can bypass machine learning-based detection relying on static code analysis by perturbing relatively few input bytes. To preserve malicious functionality, previous attacks either add bytes to existing non-functional areas of the file, potentially limiting their effectiveness, or require running computationally demanding validation steps to discard malware variants that do not correctly execute in sandbox environments. In this work, we overcome these limitations by developing a unifying framework that does not only encompass and generalize previous attacks against machine-learning models, but also includes three novel attacks based on practical, functionality-preserving manipulations to the Windows Portable Executable file format. These attacks, named Full DOS , Extend , and Shift , inject the adversarial payload by respectively manipulating the DOS header, extending it, and shifting the content of the first section. Our experimental results show that these attacks outperform existing ones in both white-box and black-box scenarios, achieving a better tradeoff in terms of evasion rate and size of the injected payload, while also enabling evasion of models that have been shown to be robust to previous attacks. To facilitate reproducibility of our findings, we open source our framework and all the corresponding attack implementations as part of the secml-malware Python library. We conclude this work by discussing the limitations of current machine learning-based malware detectors, along with potential mitigation strategies based on embedding domain knowledge coming from subject-matter experts directly into the learning process.

Tax credit management system (TCMS) implemented by the State Administration of Taxation (SAT) of China in 2014 is an innovative mechanism of tax collection and management. This paper attempts to incorporate the TCMS into the model of Allingham and Sandmo [Allingham, M. G. and Sandmo, A., Income tax evasion: A theoretical analysis, [Formula: see text]. Public Econ. 1(3–4) (1972) 323–338], and then proposes an agent-based tax compliance model combined with EWA model. In this model, enterprises are divided into three categories: enterprises paying taxes for better credit, paying taxes to avoid a punishment, and not paying taxes. Enterprises can borrow from banks based on their own tax credit rating. The experimental results based on the model show that: (i) When the probability of spot check is low, the actual tax behavior of some enterprises is inconsistent with the results of tax credit publicized by tax authorities. (ii) In order to reduce the proportion of tax evasion, we try to change the parameter variables of integral reward, audit probability, punishment, financial subsidy and loan interest rate. The results show that the punishment of fixed high loan interest rate on tax evasion enterprises can effectively restrain tax evasion and increase the proportion of enterprises with high credit rating.

In this paper, a theoretical model of tax evasion, proposed by Allingham and Sandmo, is briefly presented. This model tries to explain the taxpayer’s decision to reveal only part of the taxable income and to evade taxes in this way. The main parameters of the model are personal income, the rates of tax and penalty, probability of the tax audit. By the method of comparative statics it is possible, at least partially, to evaluate the influence of changes of the model’s parameters on a person’s decision to evade tax.As some of the assumptions of the Allingam–Sandmo model differ from taxation rules in practice or the model’s conclusions do not match the actual taxpayers’ behaviour, in this paper some criticism and improvements of the proposed model are reviewed. A comparison of the model’s assumptions and actual aspects of the tax administration in Lithuania is also provided.This article contains also a model of tax evasion with regard for the peculiarities of tax administration in Lithuania and the possible corrections of tax audit probability function.

This work presents an estimate of social security contribution evasion (SSCE) for different job categories and job sectors in Italy, among 1995 and 2016. The evasion is computed as share of the work-force that did not pay social security contribution, not as monetary evasion. The author finds a stationary trend in the size of the SSCE over time, and some significative differences in the different sectors and in the different Italian regions. The average SSCE for Italy in the 1995-2016 period is 0.149, an evasion of around 15 percent of the workforce in the social security contributions of a representative sample of Italian population, calculated on over 26,000 observations. SSCE is a well-known issue all around the world. It is a highly sensitive topic, and it is been suggested that given the aging of the population and the increasing flexibility of the work, its importance is going to increase. It is particularly interesting in a country such as Italy, where there is a huge underground economy that affects the country. Even though economists have studied the determinant and the effect of tax evasion (Allingham and Sandmo, 1972) since half a century, very few works have specifically focused on the implication of contribution evasion for social security schemes (Bailey, 2001; McGillivray, 2002) and on the determinants of contribution evasion (Bailey, 1997), especially with a quantitative approach. This work aims to contribute to the literature on SSCE, which has his own specificities that makes it different from tax evasion, offering a series of descriptive statistics on SSCE in Italy in the last twenty years. The two main goals of this study are to estimate SSCE in Italy for the different job categories, in different work sectors and in all the Italian regions between 1995 and 2016 and to provide some insights about the main causes of SSCE. In a nutshell, the findings of the author show that the highest SSCE is among self-employed and temporary worker active in the household services, building and agriculture sectors. Instead for the geographical distribution concerns, Southern Italian regions register a higher SSCE than Centre and North of Italy. The trend over the period 1998-2016 of SSC evasion is pretty much stable, while there is a gap with the 1995 estimate.

Abstract Introduction: BCL2 overexpression leading to evasion of apoptosis is common in hematologic malignancies. In DLBCL, 50% of patients (pts) overexpress BCL2 protein, 30% overexpress BCL2 and MYC (double-expressor [DE]) and 5-10% have translocations of BCL2 and MYC (double-hit [DH]), all of which are associated with a poor prognosis. We hypothesized that combination of the BCL2 inhibitor venetoclax (Ven) with chemotherapy would improve DLBCL outcomes based on pre-clinical and early clinical data. The Phase Ib part of the CAVALLI (NCT02055820) study assessed the maximum tolerated dose (MTD) of CHOP + rituximab (R) or obinutuzumab (G) with Ven (200-800mg) in non-Hodgkin lymphoma, recommending 800mg of Ven + R-CHOP for Phase II. The single-arm, multicenter Phase II part of CAVALLI investigated the efficacy of Ven + R-CHOP in all first-line (1L) DLBCL pts, by BCL2 immunohistochemistry (IHC) status within cell-of-origin (COO) subtypes, by BCL2 fluorescence in situ hybridization (FISH) and in DE and DH pts, with the intent to compare against a matched pt population in the R-CHOP arm of the GOYA Phase III study. Here we report the first safety, efficacy and biomarker analyses in all pts from this ongoing Phase II study. Methods: Eligible pts (age ≥18 yrs; Eastern Cooperative Oncology Group performance status ≤2; 1L DLBCL; International Prognostic Index score 2-5; ≥1 measurable lesion >1.5cm) were assigned to receive six 3-weekly cycles of R-CHOP + 800mg Ven daily for 10 days (Days 1-10, except Cycle 1: Days 4-10), followed by two 3-weekly cycles of 800mg Ven on Days 1-10 + R on Day 1. The primary endpoint was PET-CT response 6-8 weeks after the last R dose (EoT), according to a modified version of Lugano 2014 criteria. Secondary endpoints were progression-free survival (PFS) and safety. Biomarker analyses in CAVALLI and GOYA were performed in pre-treatment tumor samples including a BCL2 IHC assay (cutoff: 50% medium/high expression), MYC IHC assay (cutoff 40% signal), BCL2 and MYC FISH, and COO assay (Nanostring). Results: 211 pts were enrolled; 208 received any treatment and were included in efficacy and safety analyses. Overall, pt characteristics were similar for CAVALLI and GOYA, except CAVALLI enrolled more Ann Arbor Stage IV (65.4% vs 47.1%) and BCL2 IHC-positive pts (57.7% vs 50.0%). The EoT complete response rate in all pts did not differ significantly between CAVALLI and GOYA (69.2% vs 62.8%, respectively; Table 1), but was improved in BCL2-positive subgroups, specifically in BCL2 FISH-positive (70.0% vs 47.5%) and DH (71.4% vs 25.0%) pts. With 20 months' median follow-up in CAVALLI, disease progression and death had occurred in 29 and 6 pts, respectively. When compared with GOYA and adjusted for baseline covariates by Cox methodology, PFS improvement was observed in BCL2 IHC-positive pts (HR, 0.53; 95% CI: 0.30-0.93), including within both activated B-cell (ABC; HR, 0.43; 95% CI: 0.19-0.94) and germinal center B-cell (GCB; HR, 0.41; 95% CI: 0.17-0.95) COO subgroups. No PFS benefit was observed in BCL2 IHC-negative GCB pts; the BCL2 IHC-negative ABC subgroup was too small for evaluation (Figure 1). Grade 3-4 adverse events (AEs) occurred in 85% (176/208) of pts in CAVALLI versus 66% (373/574) in GOYA; the majority were cytopenias, infections and febrile neutropenia (Table 2). In CAVALLI, 1% (3/208) of AEs were fatal versus 5% (30/564) in GOYA but follow-up was longer in GOYA (57 vs 20 months). The higher rate of AEs in CAVALLI led to dose interruptions/discontinuations of both Ven and R-CHOP; 61% of pts had >90% relative dose intensity (RDI) of Ven; 73.2% of CAVALLI pts had >90% RDI of each of doxorubicin and cyclophosphamide versus 76.4% for doxorubicin and 77.6% for cyclophosphamide in GOYA. There were no major differences in grade 3-4 AEs or the RDI of R-CHOP across intention-to-treat and BCL2-positive subgroups. GCSF prophylaxis was recommended, but not uniformly delivered. Conclusions: The addition of Ven to R-CHOP in 1L DLBCL treatment resulted in improved efficacy in BCL2 IHC-positive pts compared with matched GOYA controls. Higher rates of cytopenia, infection and febrile neutropenia were observed in CAVALLI versus the R-CHOP arm in GOYA. These data further support exploration of Ven + R-CHOP in a high-risk population of BCL2-positive 1L DLBCL, including DH pts. Disclosures Morschhauser: Epizyme: Consultancy; Servier: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Feugier:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Flinn:Agios: Research Funding; Verastem: Research Funding; Celgene: Research Funding; Pharmacyclics: Research Funding; Merck: Research Funding; ArQule: Research Funding; Constellation: Research Funding; Curis: Research Funding; Genentech: Research Funding; Forma: Research Funding; Novartis: Research Funding; BeiGene: Research Funding; Pfizer: Research Funding; Forty Seven: Research Funding; TG Therapeutics: Research Funding; Portola: Research Funding; Calithera: Research Funding; Seattle Genetics: Research Funding; Verastem: Consultancy, Research Funding; Trillium: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Infinity: Research Funding; Janssen: Research Funding; Kite: Research Funding; Takeda: Research Funding. Gasiorowski:Novartis: Honoraria; MSD: Honoraria. Greil:Astra Zeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; MSD: Honoraria, Research Funding; Sandoz: Honoraria, Research Funding; Amgen: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Illés:Janssen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Johnson:Merck: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Seattle Genetics: Honoraria; Lundbeck: Consultancy, Honoraria, Other: travel, Research Funding; AbbVie Inc.: Consultancy, Honoraria, Research Funding. Lugtenburg:Genmab: Consultancy; Squibb: Consultancy; Takeda: Consultancy, Research Funding; Celgene: Consultancy; Sandoz: Consultancy; Bristol-Meyers: Consultancy; Servier: Consultancy, Research Funding; Roche: Consultancy. Salles:BMS: Honoraria, Other: Advisory Board; Servier: Honoraria, Other: Advisory Board; Servier: Honoraria; Celgene: Honoraria, Other: Advisory Board, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Epizyme: Honoraria; Morphosys: Honoraria; Abbvie: Honoraria; Acerta: Honoraria; Amgen: Honoraria; Novartis: Consultancy, Honoraria; Takeda: Honoraria; Merck: Honoraria; Pfizer: Honoraria; Janssen: Honoraria, Other: Advisory Board; Gilead: Honoraria, Other: Advisory Board. Trněný:Morphosys: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; F. Hoffman-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board, Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Gilead: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Advisory board; Sandoz: Honoraria; Abbvie: Honoraria, Research Funding. Mir:F. Hoffmann-La Roche: Employment. Kornacker:F. Hoffmann-La Roche Ltd: Employment. Punnoose:Roche: Equity Ownership; Genentech Inc: Employment. Samineni:Genentech Inc: Employment, Other: Ownership interests non-PLC. Szafer-Glusman:F. Hoffmann-La Roche Ltd: Employment, Other: Ownership interests PLC. Petrich:Abbvie: Employment, Other: Ownership interests PLC. Sinha:F. Hoffmann-La Roche Ltd: Employment. Mobasher:Genentech Inc: Employment; F. Hoffmann-La Roche Ltd: Other: Ownership interests non-PLC. Zelenetz:Celgene: Consultancy; Abbvie: Research Funding; Gilead: Consultancy, Research Funding; AstraZeneca: Consultancy; Genentech/Roche: Consultancy, Research Funding; Novartis/Sandoz: Consultancy; Amgen: Consultancy.

Anaplastic Large Cell Lymphoma (ALCL) is an aggressive subtype of T-cell lymphoma. ALCLs are stratified based on the presence of anaplastic lymphoma kinase (ALK) translocations. ALK negative (ALK-ALCLs) are heterogeneous subtypes characterized by higher aggressiveness and poorer outcome than ALK+ALCL. The molecular and genetic asset of ALK-ALCLs has recently begun to emerge (i.e. JAK/STAT3 activating mutations, DUSP22, TP63, TP53 and IRF4 rearrangements), but an exhaustive picture of the molecular drivers leading to ALK-ALCLs transformation, progression, and immune evasion is still lacking. Long non coding RNAs (LncRNAs) are transcripts longer than 200 nucleotides with different regulatory functions ranging from transcriptional regulation to structural functions, which are emerging as relevant players in many cellular processes including cancer. Using deep RNA-sequencing profiling combined with de novo transcriptome assembly, we explored and validated the potential contribution of non-coding RNAs in a large series of ALCLs. 24 lncRNAs were found specifically enriched in ALCL samples. Among these, a 70Kb chromatin associated lncRNA (BlackMamba) was identified as preferentially associated with the ALK-ALCLs subtypes and was shown to be a target of the JAK/STAT3 signaling. BlackMamba was overexpressed in ALK-ALCL patient samples as well as in patient-derived tumor xenograft (PDTX) models. Its shRNA mediated knockdown (KD) in ALK-ALCL cells reduces cell proliferation and clonogenicity. BlackMamba KD cells also showed a remarkable increase in the number of multinucleated cells (without ploidy alteration) providing evidence that this lncRNA may be required for correct cytokinesis. To better characterize the role of BlackMamba we performed RNA-sequencing profiling in BlackMamba KD ALK-ALCL cells showing that this lncRNA affects primarily the expression of genes involved in cytoskeleton organization and remodeling. Noticeably, the DNA-helicase HELLS emerged among the most relevant BlackMamba target gene in ALK-ALCL cells and patients. Loss of BlackMamba causes profound reduction of HELLS concomitant with a reorganization of chromatin markers (reduction of K4me3 and increase of K27me3) in the HELLS locus. To test whether HELLS enforces BlackMamba-mediated transcription, we silenced HELLS by shRNA approach in ALK-ALCLs. Noticeably, loss of HELLS led to a reduction in cell growth, a delay in the duplication rate and a dramatic drop of clonogenicity potential of ALK-ALCL cells. This phenotype was also associated with an increased number of multinucleated cells, phenocopying the BlackMamba KD cells. We also showed that, HELLS KD causes expression changes in a subset of cytoskeleton-related genes previously identified as BlackMamba targets confirming that HELLS is a crucial mediator of BlackMamba function. Indeed, ectopic over-expression of HELLS in BlackMamba KD cells rescued the cell growth defects induced by the loss of lncRNA mitigated the polynucleation phenotype and restored the baseline expression of BlackMamba target genes. Being established that lncRNAs affect gene expression by recruiting chromatin remodeling complexes to target promoters or enhancers we also investigated whether BlackMamba may associates with HELLS and dictates its chromatin positioning in ALK-ALCL cells. By RNA-immunoprecipitation (RIP) we showed that HELLS binds to BlackMamba at in two distinct regions the 3'-end of the lncRNA. Next, by Chromatin Immunoprecipitation (ChIP) we demonstrated that HELLS is associated to BlackMamba target gene promoters exclusively in ALK-ALCLs in which BlackMamba is expressed. Collectively, these data demonstrate the existence of a new lncRNA-dependent mechanism controlling the recruitment of HELLS on chromatin sites and its expression in lymphomas. The axis BlackMamba-HELLS sustains the neoplastic phenotype of ALK-ALCL representing a potential vulnerability of ALCL cells. Disclosures Merli: Mundipharma: Honoraria; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding; Sandoz: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel Expenses; Janssen: Honoraria; Takeda: Honoraria, Other: Travel Expenses; Gilead: Honoraria.

Introduction: The programmed cell death 1 (PD-1) monoclonal antibodies (MoAbs) nivolumab and pembrolizumab induce response rates exceeding 70% in relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL). The lack of response to PD-1 MoAbs, and the relapse occurring in most patients who had responded to PD-1 blockade suggest that tools to identify the determinants of response/resistance to PD-1 MoAbs are urgently required. We hypothesized that the characterization of the mutational profile of circulating tumor DNA (ctDNA) could represent a valuable tool to track clonal evolution-driven resistance to checkpoint inhibitors. Patients and Methods: 21 R/R cHL (median age, 32 years; range, 19-51) who had received a median of 5 (range, 3-7) chemotherapy lines, including autologous stem cell transplantation (77%) and brentuximab vedotin (100%), were treated with PD-1 MoAbs. Blood samples were profiled by CAPP-Seq strategy. We analyzed ctDNA and paired DNA from peripheral blood mononuclear cells (PBMCs), as source of germline DNA to filter out polymorphism and sequencing errors. A targeted resequencing panel optimized to include the coding exons and splice sites of 133 genes (320 Kb) that are recurrently mutated in B-cell lymphomas was used. Libraries were prepared from ctDNA and germline gDNA according to the CAPP-seq targeted enrichment strategy (Nimblegen-Roche) and subjected to ultra-deep-next generation sequencing (NGS) using the Nextseq 500 platform (Illumina). The sequencing was performed to obtain a depth of coverage >2000x in >80% of the target region in all samples, which allowed a sensitivity of 3x10-3. A stringent and completely automated bioinformatic pipeline was applied to call non-synonymous somatic mutations, using the somatic function of VarScan2. Results: After a median of 26 (range, 9-63) cycles of PD-1 inhibitors best response was complete remission (CR) for 9 patients (42%), partial remission (PR) for 6 (29%) and progressive disease (PD) for 6 (29%). Patients achieving PR experienced a disease control lasting for 4.5 to 24 months and subsequently underwent PD. Plasma and PBMC samples were collected at baseline, every five cycles of therapy, and end-of-therapy (EOT). At baseline, 18 of 21 patients could be successfully genotyped, whereas three were not. Evaluable patients showed a mean (±SD) number of mutated genes and mutations per patient of 7.3±5.1 (range, 2-22) and 9.9±8.4 (range, 2-37), respectively. Genes recurrently affected by non-synonymous somatic mutations in >20% of R/R cHL included STAT6 (45%), SOCS1 (40%), ITPKB (35%), GNA13 (35%), TP53 (20%), TNFAIP3 (15%). At baseline, no association of distinct DNA mutations with resistance to PD-1 inhibitors could be demonstrated. Signaling pathways targeted by DNA mutations included JAK-STAT, NF-κB, PI3K-AKT, cytokine, NOTCH, immune evasion. The concentration of ctDNA reported as haploid genome equivalent per ml (hGE/ml) was 592.2 (range, 2-2,746), with values of hGE/ml detected in PD patients being significantly higher as compared to CR patients (P=.0437). As compared to cycle 0, the hGE/ml of ctDNA at cycle 5 showed a significant reduction (592.2 vs. 67, P<.0008) which was followed by further hGE/ml decline in CR patients (to 14 P=.05) and further hGE/ml increase in PD patients (to 1,300 P=.1). At cycle 5, all CR/PR patients showed complete disappearance of baseline mutations, which were replaced by completely novel clones. In all CR/PR patients, this pattern of "clonal reshaping" was repeatedly detected over time. In striking contrast, at cycle 5, PD patients showed the persistence of baseline mutations. In all PD patients, this pattern of "clonal persistence", was repeatedly detected over time. In 4 patients, resistance to PD-1 inhibitors was associated with the appearance of a TP53 mutated clone. Although, a formal correlation of circulating DNA mutations with standard FDG-PET imaging was outside the objective of this study, both the "clonal reshaping" and "clonal persistence" patterns could be demonstrated to correlate with the results of FDG-PET. Conclusions: Analysis of ctDNA allows detecting tumor-specific mutations in R/R cHL. The longitudinal tracking of circulating DNA mutations in these patients identifies two different patterns of clonal evolution associated with sensitivity (clonal reshaping) or resistance (clonal persistence) to checkpoint blockade. Disclosures Santoro: Eisai: Consultancy, Speakers Bureau; Novartis: Speakers Bureau; Lilly: Speakers Bureau; Sandoz: Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Arqule: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; Celgene: Speakers Bureau; Servier: Consultancy, Speakers Bureau; Takeda: Speakers Bureau; BMS: Speakers Bureau; Roche: Speakers Bureau; Abb-Vie: Speakers Bureau; Amgen: Speakers Bureau; BMS: Consultancy; Bayer: Consultancy, Speakers Bureau; MSD: Speakers Bureau. Rossi:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Other: Scientific advisory board; Janseen: Honoraria, Other: Scientific advisory board; Roche: Honoraria, Other: Scientific advisory board; Astra Zeneca: Honoraria, Other: Scientific advisory board. Carlo-Stella:ADC Therapeutics: Consultancy, Other: Travel, accommodations, Research Funding; Sanofi: Consultancy, Research Funding; Celgene: Research Funding; Janssen Oncology: Honoraria; MSD: Honoraria; Servier: Consultancy, Honoraria, Other: Travel, accommodations; Amgen: Honoraria; Boehringer Ingelheim: Consultancy; Novartis: Consultancy, Research Funding; F. Hoffmann-La Roche Ltd: Honoraria, Other: Travel, accommodations, Research Funding; BMS: Honoraria; Janssen: Other: Travel, accommodations; Takeda: Other: Travel, accommodations; Rhizen Pharmaceuticals: Research Funding; AstraZeneca: Honoraria; Genenta Science srl: Consultancy.

Background CD47 is an innate immune checkpoint that binds signal regulatory protein alpha (SIRPα) and delivers a "do not eat" signal to suppress macrophage phagocytosis. Overexpression of CD47 serves as a mechanism of immune surveillance evasion, and is found to be associated with poor prognosis in both hematologic and solid malignancies. TTI-622 is a fusion protein consisting of the CD47-binding domain of human SIRPα linked to the Fc region of human IgG4. It is designed to enhance phagocytosis and antitumor activity by preventing CD47 from delivering its inhibitory signal as well as generating a moderate pro-phagocytic signal via IgG4 Fc. Importantly, unlike many CD47-blocking agents, TTI-622 does not bind to human red blood cells. Methods TTI-622-01 is an ongoing multicenter, Phase 1 study of the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary antitumor activity of TTI-622 in adult patients with relapsed/refractory (R/R) lymphoma (NCT03530683). Based on a modified 3+3 scheme, weekly doses are escalated through pre-planned dose levels ranging from 0.05 to 8 mg/kg. The observation period for dose limiting toxicity (DLT) is the initial 3 weeks of treatment. Safety monitoring includes weekly clinical laboratories and assessments of adverse events (AEs) based on CTCAE v 4.03. Blood samples are collected for PK analysis and assessment of receptor occupancy on normal peripheral T cells. Disease assessments are performed per Lugano criteria every 8 weeks within the first 6 months, every 3 months up to two years, and every 6 months thereafter until the end of treatment. Results As of the July 16, 2020 cutoff, 25 patients (12M/13F) with a median age of 68 years (range 24-86) have received dose levels of 0.05−8 mg/kg with testing at 8 mg/kg ongoing. Patients with the following histologies have been enrolled: diffuse large B-cell lymphoma (DLBCL; n=13), Hodgkin lymphoma (n=5), follicular lymphoma (FL; n=2), peripheral T-cell lymphoma (PTCL; n=2), cutaneous T-cell lymphoma with CD30 negative large cell transformation (CTCL-LCT, n=2), and mantle cell lymphoma (n=1). Disease stages at entry have been III or IV in 23 patients; patients had received a median of 3 (range 1-9) prior systemic therapies including CAR-T in 5 patients and HSCT in 6 patients. Treatment-related AEs have been reported in 12 (48%) patients. Most AEs have been grade 1 or 2. The most frequent treatment-related AEs include thrombocytopenia (n=4; 1 grade ≥3), neutropenia (n=3; 3 grade ≥3) and fatigue (n=3; 0 grade ≥3). Grade 4 thrombocytopenia occurred in 1 patient in the 8 mg/kg cohort and accounted for the only DLT and treatment-related serious AE reported to date. This event that occurred on Day 8 was not associated with bleeding and resolved within 1 day after prophylactic platelet transfusion. Mild to moderate platelet decreases seen in the majority of patients generally occurred on dosing days and recovered quickly to baseline levels. No other grade ≥3 thrombocytopenia have been observed in the 4 other DLT evaluable patients dosed with 8 mg/kg to date. Preliminary PK results suggest dose-dependent increases in exposure following both single and repeated TTI-622 infusions. PD results indicate that end-of-infusion CD47 receptor occupancy (RO) is above 60% at doses ≥2 mg/kg and that RO is more sustained with TTI-622 doses ≥1 mg/kg compared to lower doses. Objective responses have been achieved in 5 patients, including 1 complete response (CR) in DLBCL (0.8 mg/kg) and 4 partial responses (PR) in PTCL (2 mg/kg), DLBCL (4 mg/kg), CTCL-LCT and FL (8 mg/kg). Initial responses were achieved at the first disease assessment (week 8) in all 5 responders including initial PR in the patient who subsequently achieved CR at week 36 (See Figure 1). In the dose range of 0.8-8 mg/kg, objective responses occurred in 31% (5/16) of patients with ≥1 post-treatment response assessment (See Table 1). Two of 4 response evaluable patients in the ongoing 8 mg/kg cohort achieved a PR, and 2 other patients have been on treatment for <8 weeks. Conclusions Results to date from this ongoing Phase 1 study in patients with R/R lymphomas indicate that weekly doses of TTI-622 up to 4 mg/kg are well tolerated with dose-dependent increases in exposure and RO. TTI-622 has shown activity in R/R lymphoma with objective responses across a broad dose range (0.8-8 mg/kg) and in multiple histologies. The study is currently evaluating the 8 mg/kg dose level. Disclosures Patel: Pharmacyclics: Consultancy, Speakers Bureau; Adaptive Biotechnologies: Consultancy; Janssen: Consultancy, Speakers Bureau; Genentech: Consultancy, Speakers Bureau; Kite: Consultancy; Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Research Funding, Speakers Bureau; BeiGene: Consultancy. Ramchandren:Seattle Genetics, Sandoz-Novartis, Pharmacyclics/Janssen, Bristol-Myers Squibb: Consultancy; Merck, Seattle Genetics, Janssen, Genentech: Research Funding. Lesokhin:Juno: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Janssen: Research Funding; GenMab: Consultancy, Honoraria; Serametrix Inc.: Patents & Royalties; Takeda: Consultancy, Honoraria. von Keudell:Pharmacyclics: Research Funding; Genentech: Research Funding; Bayer: Research Funding. Cheson:Symbio: Membership on an entity's Board of Directors or advisory committees; Morphosys: Consultancy; GSK: Membership on an entity's Board of Directors or advisory committees; Jannsen: Consultancy; Pharmacyclics: Consultancy, Research Funding; Abbvie: Consultancy, Research Funding; TG Therapeutics: Speakers Bureau; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Trillium: Research Funding; Kite: Consultancy; Parexel: Consultancy. Zonder:Intellia, Amgen, Takeda, Janssen, Regeneron, Alnylam, Caelum, Oncopeptides: Consultancy; BMS, Celgene: Research Funding. Seymour:Seattle Genetics: Research Funding; Merck: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen/Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Genentech: Research Funding; Bristol-Myers Squibb: Research Funding. Catalano:Trillium Therapeutics Inc.: Current Employment. Lin:Trillium Therapeutics Inc.: Current Employment. Uger:Trillium Therapeutics Inc.: Current Employment. Petrova:Trillium Therapeutics Inc.: Current Employment. Roberge:Trillium Therapeutics Inc.: Current Employment. Shou:Trillium Therapeutics Inc.: Current Employment. Iyer:Target Oncology: Honoraria; Seattle Genetics, Inc.: Research Funding; Rhizen: Research Funding; CRISPR: Research Funding; Curio Biosciences: Honoraria; Trillium: Research Funding; Daiichi Sankyo: Consultancy; Legend Biotech: Consultancy; Spectrum: Research Funding; Merck: Research Funding; Afffimed: Research Funding.

Abstract Introduction: Preclinical data suggest that PD-1 and PD-L1/PD-L2 mediate immune evasion in CLL. However, clinical data (Ding, BLOOD 2017) demonstrate that pembrolizumab monotherapy (pembro) is ineffective in relapsed/refractory (r/r) CLL patients (pts) (ORR 0%, med PFS 2.4 months). Additional data with an anti-PD1 demonstrated a 90% failure rate in Richter's Transformation (RT) with a med 2-month OS (Rogers, BJH 2018). Combinations may represent the future of anti-PD-1 therapy in CLL/RT, especially in RT pts rel/ref to ibrutinib, where median OS is ~3.5 mos. We hypothesized synergistic activity with PD-1 + PI3K blockade. Umbralisib (UMB), is a highly-specific PI3K-δ inhibitor with additional effects on casein kinase-1 epsilon (CK-1ε), which may have an inhibitory effect on Treg function (Deng et al, 2016). We tested the safety and activity of UMB in combination with the anti-CD20 mAb ublituximab (UTX) and pembro in r/r CLL and RT - the first reported combination of a PD-1 inhibitor + PI3K-δ inhibitor in this population. Methods: Ph I (3+3 design), multicenter study to assess the safety/efficacy of UMB + UTX + pembro in pts with r/r CLL and RT. Treatment for CLL pts involved three stages: Induction: UMB (800mg daily) and UTX (900mg 3 out of 4 wks) for the first two 28-day cycles. Consolidation: Pembro (dose level 1=100mg, dose level 2=200mg) was then initiated every 3 wks in combination with UMB and UTX (900mg week 2 of cycle 4 and 6) for cycles 3-6. Maintenance: Cycle > 6, UMB 800 mg daily until progressive disease (PD) or unacceptable AE. For RT pts, all study drugs are started in cycle 1 with the following schedule: UMB 800 mg daily; UTX 900 mg cycle 1 (D1, 8, 15), D1 cycles 2-4, cycle 7 and q3 cycles thereafter; and pembro D3 of cycle 1 and D2 of cycles 2-4. The primary endpoint is safety of the triple combination with efficacy as a secondary endpoint. Response assessments for CLL, based on the iwCLL 2008 criteria, were performed after cycles 2, 6 and 12. RT response assessments (Cheson 2007) were completed at the end of cycles 2, 4 and every 3 cycles until month 12. Peripheral blood and/or bone marrow biopsy, enriched for mononuclear cells, were obtained for correlative analyses at screening, month 2 and 6. Results: Fourteen pts have been treated to date: 9 with CLL (3 at 100 mg pembro / 6 at 200 mg pembro) and 5 with RT (4 at 100 mg pembro / 1 at 200 mg). Baseline demographics were as follows: male/female (9/5), med age 71 yrs (range 60-81), med prior therapies 2 (1-8), 79% were refractory to immediate prior therapy. 10 pts had prior ibrutinib of which 9 were ibrutinib refractory. 64% of pts had at least 1 high risk genetic feature (del17p, del11q, TP53 mut, NOTCH1 mut or complex karyotype). AE's (all causality) were manageable. Grade 3/4 AE's occurring in ≥ 3 pts included neutropenia (n=6, 43%), ALT/AST increase (n=3, 21%) and hypophosphatemia (n=3, 21%). One DLT occurred in a CLL pt at 200 mg dose level (ALT/AST elevation) which trigged expansion to 6 pts. No additional DLTs were reported, and no MTD was achieved. No increase in expected grade ≥ 3 PI3Kδ-associated toxicities were noted (1 pneumonitis event, no colitis events). ORR was 89% for CLL pts with ORR of 75% in BTK refractory CLL pts (3/4). Notably 2/4 BTK refractory CLL pts achieved a response to UMB + UTX (U2) induction alone prior to the addition of pembro. 4/5 RT pts were eligible for efficacy evaluation with 50% ORR (2/4, CR). The 2 RT CRs were durable and are ongoing (15+ mos and 7+ mos); both pts were ibrutinib refractory and had 7 (including SCT) and 8 prior lines respectively, and one had failed CAR-T. With a med follow up of 15 mos, 10/14 (71%) remain progression free (range 3 - 44 mos, Fig 1), including one CLL pt who completed consolidation and has been off therapy for 27+ mos. Sequential sampling for correlative studies demonstrated modest changes in Tregs numbers (Fig 2). Conclusion: The triplet combination of umbralisib + ublituximab + pembro was well-tolerated. Responses were durable in BTK refractory, high risk pts, including two CR's in RT pts. In contrast to pembro monotherapy, data suggest that CLL/RT pts who achieve ≥ PR with this checkpoint inhibitor-containing regimen can achieve durable responses. Correlative studies suggest that maintenance of Tregs may limit autoimmune sequelae. Enrollment is ongoing in both the CLL (BTK refractory only) and RT cohorts. Disclosures Mato: AbbVie: Consultancy, Research Funding; Portola: Research Funding; Regeneron: Research Funding; AstraZeneca: Consultancy; Johnson & Johnson: Consultancy; Celgene: Consultancy; Medscape: Honoraria; TG Therapeutics: Consultancy, Research Funding; Pharmacyclics, an AbbVie Company: Consultancy, Research Funding; Acerta: Research Funding; Prime Oncology: Honoraria. Svoboda:Regeneron: Research Funding; KITE: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Consultancy, Research Funding; Kyowa: Consultancy; Seattle Genetics: Consultancy, Research Funding; Merck: Research Funding. Schuster:Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Nordic Nanovector: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Honoraria, Research Funding; Dava Oncology: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Honoraria, Research Funding. Becker:GlycoMimetics: Research Funding. Brander:DTRM: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; BeiGene: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; Novartis: Consultancy, Other: DSMB; Pharmacyclics, an AbbVie Company: Consultancy, Honoraria, Research Funding; Acerta: Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; TG Therapeutics: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; Teva: Consultancy, Honoraria; Genentech: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding; AbbVie: Consultancy, Honoraria, Other: Institutional research funding for non investigator initiated clinical trial, Research Funding. Dwivedy Nasta:Aileron: Research Funding; Pharmacyclics: Research Funding; Debiopharm: Research Funding; Incyte: Research Funding; Rafael/WF: Research Funding; Roche: Research Funding; Takeda/Millenium: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Merck: Other: DSMC. Landsburg:Takeda: Consultancy; Curis: Consultancy, Research Funding. Kennard:AbbVie, Gilead, Verastem: Consultancy. Zelenetz:Abbvie: Research Funding; Celgene: Consultancy; AstraZeneca: Consultancy; Novartis/Sandoz: Consultancy; Amgen: Consultancy; Gilead: Consultancy, Research Funding; Genentech/Roche: Consultancy, Research Funding. Purdom:TG Therapeutics: Employment, Equity Ownership. Paskalis:TG Therapeutics: Employment, Equity Ownership. Sportelli:TG Therapeutics: Employment, Equity Ownership. Miskin:TG Therapeutics: Employment, Equity Ownership. Weiss:TG Therapeutics: Employment, Equity Ownership. Shadman:Gilead Sciences: Research Funding; Celgene: Research Funding; AstraZeneca: Consultancy; Beigene: Research Funding; AbbVie: Consultancy; Genentech: Research Funding; Qilu Puget Sound Biotherapeutics: Consultancy; Genentech: Consultancy; Mustang Biopharma: Research Funding; Acerta Pharma: Research Funding; TG Therapeutics: Research Funding; Pharmacyclics: Research Funding; Verastem: Consultancy.

Background: Cluster of differentiation 47 (CD47), a widely expressed cell-surface ligand,is overexpressed in various malignancies and is correlated with worse outcomes in NHL. Interaction of CD47 and signal regulatory protein-α (SIRPα) delivers an antiphagocytic 'don't eat me' signal to promote tumor cell evasion from macrophages. CC-90002 is a humanized IgG4-PE CD47 antibody that inhibits CD47-SIRPα interaction and enabled phagocytosis across a panel of cancer cell lines (Narla et al. AACR.2017). In addition to high binding affinity, CC-90002 is potentially differentiated from other CD47 immunotherapies by its lack of ability to induce hemagglutination of red blood cells or hemolysis in nonclinical studies. CD47 antibodies can synergize with the CD20 antibody rituximab to induce phagocytosis of NHL cells in vitroand to eliminate lymphoma in mouse models (Chao et al. Cell.2010). We therefore examined CC-90002 plus rituximab for treatment of R/R NHL. Methods: This 2-part, phase I, multicenter study (CC-90002-ST-001; NCT02367196) is evaluating CC-90002 in subjects with advanced solid and hematologic malignancies. Part B of the study (reported here) is examining CC-90002 in combination with rituximab in subjects with CD20-positive R/R NHL. Dose escalation followed a modified 3+3 design. Subjects received escalating doses of CC-90002 intravenously at 4, 8, 15, 20, or 30 mg/kg every 2 weeks (Q2W) on days 1 and 15 plus rituximab 375 mg/m2 given on days −15, −8, and −1 and day 8 of cycles 1-6, 8, 10, and 12 in 28-day cycles. Primary endpoints are dose-limiting toxicities (DLTs), nontolerated dose (NTD), and maximimum tolerated dose. Secondary endpoints are pharmacokinetics, preliminary efficacy per International Working Group Response Criteria for NHL (Cheson et al. J Clin Oncol.2014), and frequency of antidrug antibodies. Results: Overall, 28 subjects have been enrolled and 24 were treated. As of July 5, 2019, 20 subjects had discontinued the study, most commonly for progressive disease (PD; n=9) or death (n=7). The median age at enrollment was 64 years (range, 27−81), and subjects had received a median of 3 prior systemic therapies (range, 2−9). Subjects received a median of 2 cycles of CC-90002 plus rituximab (range, 1−18). There were no CC-90002 dose reductions but 7 subjects had their dose interrupted, mostly because of thrombocytopenia and neutropenia. The NTD was established as 30 mg/kg Q2W.DLTs occurred in 3 subjects; 1 subject developed dyspnea attributed to an infusion-related reaction at 15 mg/kg Q2W CC-90002 and 2 subjects had grade 3 thrombocytopenia requiring platelet transfusion occurring at 30 mg/kg Q2W CC-90002. The most common adverse events (AEs) were hematologic (Table). Although anemia was common, there was no evidence of hemolysis. The most frequent grade 3/4 AEs were neutropenia (38%) and thrombocytoenia (21%). Seven deaths occurred on study or in follow-up, 6 from PD or complications related to NHL and 1 due to an AE (cytokine release syndrome in a subject who discontinued CC-90002 for PD and enrolled in another trial within the follow-up period). There were no treatment-related deaths. The overall response rate was 13% (95% CI, 2.7−32.4) and the disease control rate was 25% (95% CI, 9.8−46.7; Figure). One subject achieved a durable complete response (8 mg/kg; ongoing in cycle 18) and 2 had partial responses (15 mg/kg and 20 mg/kg); 3 subjects had stable disease. Among responders, the median duration of response was 3.9 months (95% CI, 1.9−3.9). CC-90002 exhibited linear pharmacokinetics at doses ≥15 mg/kg, suggesting target saturation at 15 mg/kg. In addition, a longer half-life was observed at higher (≥15 mg/kg) versus lower doses (t1/2≈ 3−7 days vs 1 day). Conclusions: The CD47-SIRPα checkpoint inhibitor, CC-90002,plus rituximab demonstrated tolerability and modest clinical activity in this early-phase study of heavily pretreated R/R NHL subjects. AEs were predominantly grade 1/2; cytopenias were the most common AEs with dose-limiting thrombocytopenia observed at 30 mg/kg Q2W. In contrast to other CD47-targeting immunotherapies and consistent with results of preclinical studies of CC-90002, hemolysis at a starting dose of up to 30 mg/kg CC-90002 was not observed. These preliminary data support further evaluation of targeting the CD47-SIRPα pathway in combination with rituximab in NHL. Disclosures Abrisqueta: Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Roche: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau. Sancho:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: Advisory board; Novartis: Honoraria; Kern Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Celltrion: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squib: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cordoba:Janssen: Consultancy, Honoraria, Speakers Bureau; Servier: Consultancy, Honoraria, Speakers Bureau; Kyowa-Kirin: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Research Funding, Speakers Bureau; Roche: Honoraria, Speakers Bureau; FUNDACION JIMENEZ DIAZ UNIVERSITY HOSPITAL: Employment; Celgene: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy. Persky:Sandoz: Consultancy; Morphosys: Other: Member, Independent Data Monitoring Committee; Debiopharm: Other: Member, Independent Data Monitoring Committee; Bayer: Consultancy. Andreadis:Juno: Research Funding; Pharmacyclics: Research Funding; Roche: Equity Ownership; Novartis: Research Funding; Jazz Pharmaceuticals: Consultancy; Celgene: Research Funding; Kite: Consultancy; Gilead: Consultancy; Merck: Research Funding; Genentech: Consultancy, Employment. Huntington:Pharmacyclics: Honoraria; Genentech: Consultancy; Bayer: Consultancy, Honoraria; DTRM Biopharm: Research Funding; AbbVie: Consultancy; Celgene: Consultancy, Research Funding. Carpio:University Hospital Vall D'Hebron: Employment. Morillo Giles:Hospital Universitario Fundacion Jimenez Diaz: Honoraria. Wei:Celgene Corp.: Employment, Equity Ownership. Li:Celgene Corp.: Employment, Equity Ownership. Zuraek:Celgene Corp.: Employment, Equity Ownership, Other: Travel, Accommodations, Expenses. Burgess:University of California: Other: Volunteer clinical faculty, without salary, Patents & Royalties: Patent - T315A and F317I mutations of BCR-ABL kinase domain; Celgene Corporation: Employment, Equity Ownership, Patents & Royalties: Patent - CD47 antibodies and methods of use thereof. Hege:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties; Arcus Biosciences: Membership on an entity's Board of Directors or advisory committees; Mersana Therapuetics: Membership on an entity's Board of Directors or advisory committees; Society for Immunotherapy of Cancer: Membership on an entity's Board of Directors or advisory committees. Martín:iQone: Consultancy; Gilead: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: Travel Expenses; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding; Kiowa Kirin: Consultancy; Servier: Honoraria, Other: Travel Expenses; Teva: Research Funding; Janssen: Honoraria, Other: Travel Expenses, Research Funding.

Fairness in the sense of tax equality is a fundamental principle in modern tax systems. In recent years tax administrations have been making tremendous advances in moving from paper tax returns to a far-reaching digitalisation of the taxation procedure. This paper represents the first attempt to examine the impact of digitalisation of the tax administration on fair taxation through model theory. The model suggested in this paper is based on Allingham and Sandmo’s tax evasion model (Allingham & Sandmo, 1972, 323–338) supplemented by psychological costs of tax evasion and compliance costs and then transferred to the context of digitalisation and fair taxation. The model is intended to mathematically derive the influence of various digitalisation measures on the taxpayer's decision to behave fairly. It implies that the objective of fair taxation should be promoted with a mix of deterrent and encouraging measures.

This article quantifies personal income tax compliance by regions for the first time in Spain and identifies the factors explaining differences in tax compliance between regions, an aspect that has scarcely been analyzed in the literature. To this end, and in addition to the dynamic and spatial components considered by Alm and Yunus, this article considers the variables included in the classical tax evasion model of Allingham and Sandmo, as well as tax morale and political-institutional variables, including those linked to the country’s fiscal decentralization. The results obtained confirm, on one hand, those reached in the very extensive literature studying tax evasion from the individual perspective (including the importance of the dynamic element) and, on the other, the relevance of the spatial component in explaining tax compliance, so that greater or lesser tax compliance is partly explained by factors such as the tax behavior of neighbors or how those neighbors are treated by the public sector.

Penalty rates and probability of fraud detection are among the most important factors shaping taxpayer’s compliance. While the first of those factors may be directly controlled by tax authorities the second is usually indirectly influenced by the amount and efficiency of resources employed to detect tax evasion (Allingham, Sandmo 1972, p. 330). In order to increase fraud detection rate tax authorities may implement diversified strategies. They include inter alia the application of various methods to select taxpayers for tax audits. In most of the cases these methods are used interchangeably or complement each other. Although applied quite often in practice by tax authorities they are comparatively rarely addressed by the economists in their publications. In fact, literature sources on this topic are sparse and published mainly by the OECD. One of the methods used to select taxpayers for tax audits is based on the so-called external risk areas. In Poland, this method was introduced shortly after accession to the European Union as a tool of the external risk management strategy in the public administration. Both this strategy and audit targeting tools have evolved tremendously since its first implementation. This article attempts to evaluate the application of external risk areas to select taxpayers for tax audits in Poland. The author uses various indicators to measure the efficiency of tax audits and compare this efficiency taking into account different tax audit selection methods.