Shared and distinct genetics of pure type 1 diabetes and type 1 diabetes with celiac disease, homology in their auto-antigens and immune dysregulation states: a study from North India.

AIM: This study was undertaken to explicate the shared and distinctive genetic susceptibility and immune dysfunction in patients with T1D alone and T1D with CD (T1D + CD). METHODS: A total of 100 T1D, 50 T1D + CD and 150 healthy controls were recruited. HLA-DRB1/DQB1 alleles were determined by PCR-sequence-specific primer method, SNP genotyping for CTLA-4 and PTPN22 was done by simple probe-based SNP-array and genotyping for INS-23 Hph1 A/T was done by RFLP. Autoantibodies and cytokine estimation was done by ELISA. Immune-regulation was analysed by flow-cytometry. Clustering of autoantigen epitopes was done by epitope cluster analytical tool. RESULTS: Both T1D alone and T1D + CD had a shared association of DRB1*03:01, DRB1*04, DRB3*01:07/15 and DQB1*02. DRB3*01:07/15 confers the highest risk for T1D with relative risk of 11.32 (5.74-22.31). Non-HLA gene polymorphisms PTPN22 and INS could discriminate between T1D and T1D + CD. T1D + CD have significantly higher titers of autoantibodies, expression of costimulatory molecules on CD4 and CD8 cells, and cytokine IL-17A and TGF-ß1 levels compared to T1D patients. Epitopes from immunodominant regions of autoantigens of T1D and CD clustered together with 40% homology. CONCLUSION: Same HLA genes provide susceptibility for both T1D and CD. Non-HLA genes CTLA4, PTPN22 and INS provide further susceptibility while different polymorphisms in PTPN22 and INS can discriminate between T1D and T1D + CD. Epitope homology between autoantigens of two diseases further encourages the two diseases to occur together. The T1D + CD being more common in females along with co-existence of thyroid autoimmunity, and have more immune dysregulated state than T1D alone.

A systematic review of flurbiprofen 8.75 mg dose and risk of adverse events (excluding haemorrhagic) resulting from drug-drug interactions.

Background: Flurbiprofen 8.75 mg lozenges and oromucosal sprays are used for symptomatic relief of sore throat in patients aged 12 years and over. The documented adverse events of flurbiprofen use include those related to its pharmacological actions, namely, increased risk of haemorrhagic events, however other adverse events (such as nephrotoxicity and cardiac failure) have been known to occur. The likelihood of occurrence of adverse events increases when flurbiprofen is used concomitantly with some other medications. Therefore, the objective of this systematic review was to collate the current evidence on adverse events which occur with flurbiprofen 8.75 mg dose (any formulation), in particular as a result of interaction with other medicinal products, with a focus on non-haemorrhagic events. Methods: Systematic searches of the literature were conducted to identify literature on any formulation of flurbiprofen 8.75 mg up to the date of the electronic database search (data lock: 28 April 2020). Publications were screened to identify studies reporting non-haemorrhagic adverse events with flurbiprofen 8.75 mg and/or non-haemorrhagic adverse events in the comparator arm. Data extraction was performed for eligible studies according to pre-defined criteria and summarised in narratives, tables and figures. Risk of bias and certainty of evidence assessments were planned for each included study where results relating to the primary objective of the systematic review were available. Results: Of 1,528 publications identified by systematic literature searches, 26 met the inclusion criteria and were included in this review. None of these 26 studies contained information on non-haemorrhagic adverse events occurring as a result of a drug-drug interaction (interaction with concomitant medication used with flurbiprofen 8.75 mg), as per the primary objective and secondary objectives of the systematic review. Conclusion: Results from this systematic review on the risk of non-haemorrhagic events did not provide evidence for these events occurring as a result of interaction with other medicinal products. Additional appropriately designed studies would be required to confirm whether these findings suggest a true absence of risk or limitations in reporting.

High-grade glioma in infants and young children is histologically, molecularly, and clinically diverse: Results from the SJYC07 trial and institutional experience.

BACKGROUND: High-grade gliomas (HGG) in young children pose a challenge due to favorable but unpredictable outcomes. While retrospective studies broadened our understanding of tumor biology, prospective data is lacking. METHODS: A cohort of children with histologically diagnosed HGG from the SJYC07 trial was augmented with nonprotocol patients with HGG treated at St. Jude Children's Research Hospital from November 2007 to December 2020. DNA methylome profiling and whole genome, whole exome, and RNA sequencing were performed. These data were integrated with histopathology to yield an integrated diagnosis. Clinical characteristics and preoperative imaging were analyzed. RESULTS: Fifty-six children (0.0-4.4 years) were identified. Integrated analysis split the cohort into four categories: infant-type hemispheric glioma (IHG), HGG, low-grade glioma (LGG), and other-central nervous system (CNS) tumors. IHG was the most prevalent (n = 22), occurred in the youngest patients (median age = 0.4 years), and commonly harbored receptor tyrosine kinase gene fusions (7 ALK, 2 ROS1, 3 NTRK1/2/3, 4 MET). The 5-year event-free (EFS) and overall survival (OS) for IHG was 53.13% (95%CI: 35.52-79.47) and 90.91% (95%CI: 79.66-100.00) vs. 0.0% and 16.67% (95%CI: 2.78-99.74%) for HGG (p = 0.0043, p = 0.00013). EFS and OS were not different between IHG and LGG (p = 0.95, p = 0.43). Imaging review showed IHGs are associated with circumscribed margins (p = 0.0047), hemispheric location (p = 0.0010), and intratumoral hemorrhage (p = 0.0149). CONCLUSIONS: HGG in young children is heterogeneous and best defined by integrating histopathological and molecular features. Patients with IHG have relatively good outcomes, yet they endure significant deficits, making them good candidates for therapy de-escalation and trials of molecular targeted therapy.

Molecular Classification Improves Therapeutic Options for Infants and Young Children With Medulloblastoma.

Medulloblastoma in infants and young children is a major challenge to treat because craniospinal irradiation (CSI), a cornerstone of therapy for older children, is disproportionately damaging to very young children. As a result, trials have attempted to delay, omit, and replace this therapy. Although success has been limited, the approach has not been a complete failure. In fact, this approach has cured a significant number of children with medulloblastoma. However, many children have endured intensive regimens of chemotherapy only to experience relapse and undergo salvage treatment with CSI, often at higher doses and with worse morbidity than they would have initially experienced. Recent advancements in molecular diagnostics have proven that response to therapy is biologically driven. Medulloblastoma in infants and young children is divided into 2 molecular groups: Sonic Hedgehog (SHH) and group 3 (G3). Both are chemotherapy-sensitive, but only the SHH medulloblastomas are reliably cured with chemotherapy alone. Moreover, SHH can be molecularly parsed into 2 groups: SHH-1 and SHH-2, with SHH-2 showing higher cure rates with less intensive chemotherapy and SHH-1 requiring more intensive regimens. G3 medulloblastoma, on the other hand, has a near universal relapse rate after chemotherapy-only regimens. This predictability represents a significant breakthrough and affords oncologists the ability to properly risk-stratify therapy in such a way that the most curative and least toxic therapy is selected. This review examines the treatment of medulloblastoma in infants and young children, discusses the molecular advancements, and proposes how to use this information to structure the future management of this disease.

T cell reactivity to Bordetella pertussis is highly diverse regardless of childhood vaccination.

The incidence of whooping cough due to Bordetella pertussis (BP) infections has increased recently. It is believed that the shift from whole-cell pertussis (wP) vaccines to acellular pertussis (aP) vaccines may be contributing to this rise. While T cells are key in controlling and preventing disease, nearly all knowledge relates to antigens in aP vaccines. A whole-genome mapping of human BP-specific CD4+ T cell responses was performed in healthy vaccinated adults and revealed unexpected broad reactivity to hundreds of antigens. The overall pattern and magnitude of T cell responses to aP and non-aP vaccine antigens are similar regardless of childhood vaccination, suggesting that asymptomatic infections drive the pattern of T cell reactivity in adults. Lastly, lack of Th1/Th2 polarization to non-aP vaccine antigens suggests these antigens have the potential to counteract aP vaccination Th2 bias. These findings enhance our insights into human T cell responses to BP and identify potential targets for next-generation pertussis vaccines.

Genome-wide characterization of T cell responses to Bordetella pertussis reveals broad reactivity and similar polarization irrespective of childhood vaccination profiles.

The incidence of whooping cough (pertussis), the respiratory disease caused by Bordetella pertussis (BP) has increased in recent years, and it is suspected that the switch from whole-cell pertussis (wP) to acellular pertussis (aP) vaccines may be a contributing factor to the rise in morbidity. While a growing body of evidence indicates that T cells play a role in the control and prevention of symptomatic disease, nearly all data on human BP-specific T cells is related to the four antigens contained in the aP vaccines, and data detailing T cell responses to additional non-aP antigens, are lacking. Here, we derived a full-genome map of human BP-specific CD4+ T cell responses using a high-throughput ex vivo Activation Induced Marker (AIM) assay, to screen a peptide library spanning over 3000 different BP ORFs. First, our data show that BP specific-CD4+ T cells are associated with a large and previously unrecognized breadth of responses, including hundreds of targets. Notably, fifteen distinct non-aP vaccine antigens were associated with reactivity comparable to that of the aP vaccine antigens. Second, the overall pattern and magnitude of CD4+ T cell reactivity to aP and non-aP vaccine antigens was similar regardless of aP vs wP childhood vaccination history, suggesting that the profile of T cell reactivity in adults is not driven by vaccination, but rather is likely driven by subsequent asymptomatic or sub-clinical infections. Finally, while aP vaccine responses were Th1/Th2 polarized as a function of childhood vaccination, CD4+ T cell responses to non-aP BP antigens vaccine responses were not, suggesting that these antigens could be used to avoid the Th2 bias associated with aP vaccination. Overall, these findings enhance our understanding of human T cell responses against BP and suggest potential targets for designing next-generation pertussis vaccines.

Frequency of HLA alleles and KIR Ligands in Acute Myeloid Leukemia in Indian Cohort.

Relationship between various combinations of KIR ligands and HLA alleles have been studied in several diseases. The aim of this retrospective study was to estimate the frequency of HLA alleles and KIR ligands among acute myeloid leukemia patients and healthy controls in order to examine the possible association of HLA alleles and KIR ligands with AML. A total of 439 acute myeloid leukemia patients and 1317 unrelated, healthy ethnic Indian controls were included in the study. HLA typing was performed using PCR-SSP. KIR ligands were assigned by using the KIR ligand Calculator. The frequency of HLA alleles and KIR ligands in patients was then compared with the controls. As compared to controls, frequencies of HLA-A*03 and HLA-B*35 were increased in AML patients, whereas, that of HLA-C*03 was decreased. Frequencies of HLA-A*03 and HLA-C*15 were increased in male patients, however, no significant difference was observed in female patients as compared to controls. In the pediatric group, the frequencies of HLA-A*01 was decreased and that of HLA-A*03 and HLA-B*18 were increased, whereas, frequencies of HLA-B*13 was decreased and that of HLA-B*27 was increased in the adult patients. In the haplotype analysis, the frequency of HLA-A*24/B*35/DRB1*15 was increased in overall patients. In adult group, the frequency of HLA-A*01/B*44/DRB1*07 was increased in patients than in controls. No significant association was observed between KIR ligands and susceptibility/ protection to AML. Our results indicate that certain HLA alleles and haplotypes have presumptive positive or negative role in conferring protection/susceptibility to AML. Supplementary Information: The online version contains supplementary material available at 10.1007/s12288-022-01550-0.

Delayed pregnancy detection and return to fertility with extended levonorgestrel-containing oral contraceptives: A real world setting cohort study.

PURPOSE: As part of the European risk management plan of a 91-day extended levonorgestrel-containing combined oral contraceptive (COCLNG ), a study was performed to assess its safety. This analysis was conducted to examine delayed pregnancy detection and return to fertility with extended combined oral contraceptives (COC). METHODS: We conducted a retrospective cohort study in new users of 91-day COCLNG or 28-day COCLNG within a US-based healthcare claims database from 2006 to 2017. Delayed pregnancy detection during current COCLNG exposure was defined as the time between estimated pregnancy start and first prenatal care encounter. Additionally, the time between estimated pregnancy start and COCLNG discontinuation was measured. To measure return to fertility, pregnancy rates were estimated among females who discontinued treatment. 91-day COCLNG users were propensity score-matched to 28-day COCLNG users. Hazard ratio for pregnancy was calculated using Cox proportional hazards models. RESULTS: The 91-day and 28-day COCLNG users had 25 593 and 76 586 treatment episodes, respectively. The median time to pregnancy detection was 64.5 and 61.0 days (p = 0.24) in users of 91-day COCLNG and 28-day COCLNG . The median exposure time to treatment after estimated pregnancy start was 54.0 and 38.0 days (p < 0.01). In the fertility analysis, pregnancy rates were 54.82 (95% CI, 50.05-59.93) and 69.30 (95% CI, 64.98-73.82) per 1000 person-years in extended COCLNG discontinuers and 28-day COCLNG discontinuers. The adjusted hazard ratio of pregnancy was 0.77 (95% CI, 0.69-0.85). CONCLUSIONS: Small differences were observed for pregnancy rates and delayed pregnancy detection between 91-day extended COCLNG and 28-day COCLNG , which may be related to the longer days' supply of extended COCLNG . Differences in the fertility analysis may be related to unmeasured residual confounding.

Neoepitopes prediction strategies: an integration of cancer genomics and immunoinformatics approaches.

A major near-term medical impact of the genomic technology revolution will be the elucidation of mechanisms of cancer pathogenesis, leading to improvements in the diagnosis of cancer and the selection of cancer treatment. Next-generation sequencing technologies have accelerated the characterization of a tumor, leading to the comprehensive discovery of all the major alterations in a given cancer genome, followed by the translation of this information using computational and immunoinformatics approaches to cancer diagnostics and therapeutic efforts. In the current article, we review various components of cancer immunoinformatics applied to a series of fields of cancer research, including computational tools for cancer mutation detection, cancer mutation and immunological databases, and computational vaccinology.

Not all T cell epitopes are equally desired: a review of in silico tools for the prediction of cytokine-inducing potential of T-cell epitopes.

Assessment of protective or harmful T cell response induced by any antigenic epitope is important in designing any immunotherapeutic molecule. The understanding of cytokine induction potential also helps us to monitor antigen-specific cellular immune responses and rational vaccine design. The classical immunoinformatics tools served well for prediction of B cell and T cell epitopes. However, in the last decade, the prediction algorithms for T cell epitope inducing specific cytokines have also been developed and appreciated in the scientific community. This review summarizes the current status of such tools, their applications, background algorithms, their use in experimental setup and functionalities available in the tools/web servers.

Molecular classification and outcome of children with rare CNS embryonal tumors: results from St. Jude Children's Research Hospital including the multi-center SJYC07 and SJMB03 clinical trials.

Methylation profiling has radically transformed our understanding of tumors previously called central nervous system primitive neuro-ectodermal tumors (CNS-PNET). While this marks a momentous step toward defining key differences, reclassification has thrown treatment into disarray. To shed light on response to therapy and guide clinical decision-making, we report outcomes and molecular features of children with CNS-PNETs from two multi-center risk-adapted studies (SJMB03 for patients ≥ 3 years; SJYC07 for patients < 3 years) complemented by a non-protocol institutional cohort. Seventy patients who had a histological diagnosis of CNS-PNET or CNS embryonal tumor from one of the new categories that has supplanted CNS-PNET were included. This cohort was molecularly characterized by DNA methylation profiling (n = 70), whole-exome sequencing (n = 53), RNA sequencing (n = 20), and germline sequencing (n = 28). Clinical characteristics were detailed, and treatment was divided into craniospinal irradiation (CSI)-containing (SJMB03 and SJMB03-like) and CSI-sparing therapy (SJYC07 and SJYC07-like). When the cohort was analyzed in its entirety, no differences were observed in the 5-year survival rates even when CSI-containing therapy was compared to CSI-sparing therapy. However, when analyzed by DNA methylation molecular grouping, significant survival differences were observed, and treatment particulars provided suggestions of therapeutic response. Patients with CNS neuroblastoma with FOXR2 activation (CNS-NB-FOXR2) had a 5-year event-free survival (EFS)/overall survival (OS) of 66.7% ± 19.2%/83.3% ± 15.2%, and CIC rearranged sarcoma (CNS-SARC-CIC) had a 5-year EFS/OS both of 57.1% ± 18.7% with most receiving regimens that contained radiation (focal or CSI) and multidrug chemotherapy. Patients with high-grade neuroepithelial tumor with BCOR alteration (HGNET-BCOR) had abysmal responses to upfront chemotherapy-only regimens (5-year EFS = 0%), but survival extended with salvage radiation after progression [5-year OS = 53.6% ± 20.1%]. Patients with embryonal tumor with multilayered rosettes (ETMR) or high-grade glioma/glioblastoma multiforme (HGG/GBM) did not respond favorably to any modality (5-year EFS/OS = 10.7 ± 5.8%/17.9 ± 7.2%, and 10% ± 9.0%/10% ± 9.0%, respectively). As an accompaniment, we have assembled this data onto an interactive website to allow users to probe and query the cases. By reporting on a carefully matched clinical and molecular cohort, we provide the needed insight for future clinical management.

Cancer risk and tumour spectrum in 172 patients with a germline SUFU pathogenic variation: a collaborative study of the SIOPE Host Genome Working Group.

BACKGROUND: Little is known about risks associated with germline SUFU pathogenic variants (PVs) known as a cancer predisposition syndrome. METHODS: To study tumour risks, we have analysed data of a large cohort of 45 unpublished patients with a germline SUFU PV completed with 127 previously published patients. To reduce the ascertainment bias due to index patient selection, the risk of tumours was evaluated in relatives with SUFU PV (89 patients) using the Nelson-Aalen estimator. RESULTS: Overall, 117/172 (68%) SUFU PV carriers developed at least one tumour: medulloblastoma (MB) (86 patients), basal cell carcinoma (BCC) (25 patients), meningioma (20 patients) and gonadal tumours (11 patients). Thirty-three of them (28%) had multiple tumours. Median age at diagnosis of MB, gonadal tumour, first BCC and first meningioma were 1.5, 14, 40 and 44 years, respectively. Follow-up data were available for 160 patients (137 remained alive and 23 died). The cumulative incidence of tumours in relatives was 14.4% (95% CI 6.8 to 21.4), 18.2% (95% CI 9.7 to 25.9) and 44.1% (95% CI 29.7 to 55.5) at the age of 5, 20 and 50 years, respectively. The cumulative risk of an MB, gonadal tumour, BCC and meningioma at age 50 years was: 13.3% (95% CI 6 to 20.1), 4.6% (95% CI 0 to 9.7), 28.5% (95% CI 13.4 to 40.9) and 5.2% (95% CI 0 to 12), respectively. Sixty-four different PVs were reported across the entire SUFU gene and inherited in 73% of cases in which inheritance could be evaluated. CONCLUSION: Germline SUFU PV carriers have a life-long increased risk of tumours with a spectrum dominated by MB before the age of 5, gonadal tumours during adolescence and BCC and meningioma in adulthood, justifying fine-tuned surveillance programmes.

NSD1 mediates antagonism between SWI/SNF and polycomb complexes and is required for transcriptional activation upon EZH2 inhibition.

Disruption of antagonism between SWI/SNF chromatin remodelers and polycomb repressor complexes drives the formation of numerous cancer types. Recently, an inhibitor of the polycomb protein EZH2 was approved for the treatment of a sarcoma mutant in the SWI/SNF subunit SMARCB1, but resistance occurs. Here, we performed CRISPR screens in SMARCB1-mutant rhabdoid tumor cells to identify genetic contributors to SWI/SNF-polycomb antagonism and potential resistance mechanisms. We found that loss of the H3K36 methyltransferase NSD1 caused resistance to EZH2 inhibition. We show that NSD1 antagonizes polycomb via cooperation with SWI/SNF and identify co-occurrence of NSD1 inactivation in SWI/SNF-defective cancers, indicating in vivo relevance. We demonstrate that H3K36me2 itself has an essential role in the activation of polycomb target genes as inhibition of the H3K36me2 demethylase KDM2A restores the efficacy of EZH2 inhibition in SWI/SNF-deficient cells lacking NSD1. Together our data expand the mechanistic understanding of SWI/SNF and polycomb interplay and identify NSD1 as the key for coordinating this transcriptional control.

A comprehensive study of epitopes and immune reactivity among Plasmodium species.

BACKGROUND: Malaria is a life-threatening disease caused by protozoan parasite of genus Plasmodium. Various antigenic proteins of Plasmodium are considered as the major targets for the development of an effective vaccine. The aim of the current study was a comprehensive analysis of the experimentally validated epitopes of Plasmodium obtained from various immunoassays. METHODS: Plasmodium species epitopes were prefetched from Immune Epitope Database (IEDB). Species specific classification of available epitopes was done for both human and murine malaria parasites. Further, these T cell and B cell epitopes along with MHC I/II binders of different Plasmodium species were examined to find out their capability to induce IFN-γ and IL-10 using IFNepitope and IL-10 Pred, respectively. RESULTS: The species-specific classification of 6874 unique epitopes resulted in the selection of predominant human and murine Plasmodium species. Further, the attempt was made to analyse the immune reactivity of these epitopes for their ability to induce cytokines namely IFN-γ and IL-10. Total, 2775 epitopes were predicted to possess IFN-γ inducing ability, whereas 1275 epitopes were found to be involved in the induction of IL-10. CONCLUSIONS: This study facilitates the assessment of Plasmodium epitopes and associated proteins as a potential approach to design and develop an epitope-based vaccine. Moreover, the results highlight the epitope-based immunization in malaria to induce a protective immune response.

Revisiting hematopoiesis: applications of the bulk and single-cell transcriptomics dissecting transcriptional heterogeneity in hematopoietic stem cells.

Hematopoietic system (HS) is one of the most unique, adaptive and comprehensive developmental systems on which various other body systems relies on. It consists of a central pool of multipotent hematopoietic stem cells (HSCs) differentiating into lymphoid and myeloid lineage by series of gradual loss of stemness potential. Thus, this highly coordinated phenomenon of blood cell renewal ensures robust immunity and limits autoimmunity. Any disease, chronic infection or stress interrupts HS homeostasis and breaks HSCs' dormancy, thereby activating HSCs to meet the peripheral demand for different immune cells via their expansion and differentiation into more lineage-restricted progenitors, primarily within the bone marrow (BM) in adult life. Therefore, a greater understanding of the overall regulatory landscape of HSC homeostasis and their perturbations is critical for dissecting protective immunity versus autoimmunity. Recent advancements in next-generation sequencing (NGS) viz genomic, transcriptomic, epigenomic and proteogenomic methods at bulk as well as single-cell levels have increased our apprehension for HSC working model. In this review, we discussed the recent findings and computational methods used to unravel the new HSC model revised over the classical model.

Postmarketing studies: can they provide a safety net for COVID-19 vaccines in the UK?

In the current era of the COVID-19 pandemic, the world has never been more interested in the process of vaccine development. While researchers across the globe race to find an effective yet safe vaccine to protect populations from the newly emergent SARS-CoV-2 virus, more than one-third of the world has been subjected to either full or partial lockdown measures. With communities having felt the burden of prolonged isolation, finding a safe and efficacious vaccine will yield direct beneficial effects on protecting against COVID-19 morbidity and mortality and help relieve the psychological and economic load on communities living with COVID-19. There is hope that with the extraordinary efforts of scientists a vaccine will become available. However, given the global public health crisis, development of a COVID-19 vaccine will need to be fast tracked through the usual prelicensing development stages and introduced with limited clinical trial data compared with those vaccines that are developed conventionally over more than a decade. In this scenario, surveillance of the vaccine in the real world becomes even more paramount. This responsibility falls to observational researchers who can provide an essential safety net by continuing to monitor the effectiveness and safety of a COVID-19 vaccine after licensing. Postauthorisation observational studies for safety and effectiveness are complementary to prelaunch clinical trials and not a replacement. In this paper, we highlight the importance of postmarketing studies for future newly licensed COVID-19 vaccines and the key epidemiological considerations.

Long-term safety of extended levonorgestrel-containing oral contraceptives in the United States.

OBJECTIVES: To compare the safety profile of Seasonique, a 91-day levonorgestrel-containing combined oral contraceptive (COCLNG), to 28-day COCLNG regarding the risk of venous thromboembolism (VTE) and arterial thromboembolism (ATE). STUDY DESIGN: A new user cohort study was conducted in a US health care database from 2006 to 2017. Each 91-day COCLNG treatment episode in females was matched to up to four 28-day COCLNG treatment episodes by propensity score. We identified VTE cases in either (1) an inpatient setting with ICD-9 and ICD-10 diagnosis codes of PE and/or DVT in the primary position, or (2) an outpatient setting with ICD-9 or ICD-10 diagnosis codes of DVT in conjunction with an anticoagulant medication dispensing or alteplase (thrombolytic) during the 30-day period following the date of DVT diagnosis. VTE was validated using medical records. We assessed the study endpoints in the two cohorts using incidence rates and Cox proportional hazards models adjusted for potential confounders. RESULTS: Of the 25,593 treatment episodes in 91-day COCLNG and 76,586 treatment episodes in 28-day COCLNG, 35 and 68 patients had VTEs, respectively, corresponding to a hazard ratio (HR) of 1.40 (95% confidence interval [CI], 0.90-2.19). The VTE algorithm had a positive predictive value of 76.4% (95% CI, 66.2%-84.8%). ATEs were recorded in 13 and 28 episodes, respectively, with a corresponding HR of 1.21 (95% CI, 0.58-2.53). CONCLUSIONS: These results do not indicate a significant difference between 91-day COCLNG and 28-day COCLNG in terms of VTE or ATE risk. IMPLICATIONS: Compared to use of 28-day COCLNG, use of 91-day extended COCLNG was not associated with a significant difference in risk of venous and arterial thromboembolism.