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Mucopolysaccharidosis type I (MPS I) is caused by the deficiency of α-l-iduronidase, leading to the storage of dermatan and heparan sulfate. There is a broad phenotypical spectrum with the presence or absence of neurological impairment. The classical form is known as Hurler syndrome, the intermediate form as Hurler–Scheie, and the most attenuated form is known as Scheie syndrome. Phenotype seems to be largely influenced by genotype. Patients usually develop several somatic symptoms such as abdominal hernias, extensive dermal melanocytosis, thoracolumbar kyphosis odontoid dysplasia, arthropathy, coxa valga and genu valgum, coarse facial features, respiratory and cardiac impairment. The diagnosis is based on the quantification of α-l-iduronidase coupled with glycosaminoglycan analysis and gene sequencing. Guidelines for treatment recommend hematopoietic stem cell transplantation for young Hurler patients (usually at less than 30 months of age). Intravenous enzyme replacement is approved and is the standard of care for attenuated—Hurler–Scheie and Scheie—forms (without cognitive impairment) and for the late-diagnosed severe—Hurler—cases. Intrathecal enzyme replacement therapy is under evaluation, but it seems to be safe and effective. Other therapeutic approaches such as gene therapy, gene editing, stop codon read through, and therapy with small molecules are under development. Newborn screening is now allowing the early identification of MPS I patients, who can then be treated within their first days of life, potentially leading to a dramatic change in the disease’s progression. Supportive care is very important to improve quality of life and might include several surgeries throughout the life course.

503 Background: To correlate clinical features of estrogen receptor positive breast cancer with somatic mutations, massively parallel sequencing (MPS) was applied to tumor and normal DNAs accrued from patients treated with neoadjuvant aromatase inhibitors (AI). Methods: MPS was applied to 77 baseline tumor biopsy samples from the preoperative letrozole trial (JACS 2009: 208, 906) and the Z1031 trial (JCO 2011: 29, 2342) followed by targeted sequencing in another 240 trial samples. Standard statistical approaches were used to compare mutation status and clinical parameters and pathway-based correlation was used to assess interactions between signaling perturbations induced by gene mutations and response to neoadjuvant AI. Results: Eighteen genes were significantly mutated above background. Aside from PIK3CA mutations, the list is dominated by loss-of-function mutations in tumor suppressor genes. Five (RUNX1, CBFP, MYH9, MLL3 and SF3B1) have been previously linked to benign and malignant hematopoietic disorders. Clinical correlation revealed that TP53 mutation was associated with PAM50 LumB status, high-grade histology and high proliferation rates whereas loss-of-function mutations in MAP3K1 associate with PAM50 lumA status, low proliferation rates, and low grade histology. Mutations in GATA3 were associated with greater suppression of proliferation upon AI treatment suggesting mutGATA3 may predict endocrine response. Notably, mutations in MAP3K1 were more common in PIK3CA mutant cases, suggesting cooperation. Pathway analysis demonstrated that rare MAP2K4 mutations produce similar pathway perturbations as MAP3K1 mutation, a logical finding since MAP2K4 is a substrate for MAP3K1. Signaling network patterns driven by lncRNA MALAT1 mutations were associated with multiple poor clinical outcome features. Rare mutations in druggable kinases included two in the kinase domain of HER2. Conclusions: Tumor heterogeneity in luminal-type breast cancer is driven by specific patterns of somatic mutations, however most druggable or potentially prognostic mutations are infrequent. Prospective clinical trials based on these findings will require comprehensive genome sequencing approaches and large scale investigations.

Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a ligand for CXCR4 that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. We have previously shown that FT inhibition by tipifarnib downregulates CXCL12 secretion. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study (NCT02464228) is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) design to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL age >/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (wt CXCL12 3'UTR cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Tumor Whole Exon Sequencing (WES) was generated by NGS and gene expression data generated by RNA Seq. Ancillary studies also investigated the prognostic value of CXCL12 expression in pts who received standard of care treatment. Results As of 24 May 2019, 50 PTCL pts (23 AITL, 25 PTCL-NOS, 1 ALK- ALCL, 1 gamma-delta TCL) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 31 pts in the ongoing AITL histology and wt CXCL12 3'UTR cohorts. Median number of prior treatment regimens was 3; 19 pts had a prior stem cell transplant. All pts (n=48 with available safety data) had at least one treatment-emergent adverse event (TEAE); 42 (88%) had at least 1 study drug-related TEAE and 13 (27%) at least 1 drug related SAE. The most frequently observed drug-related TEAEs of Grade >3 occurring in 10% or more of pts were blood and lymphatic system disorders, including neutropenia (40%), thrombocytopenia (33%), leukopenia (25%), anemia and febrile neutropenia (19% each). There have been 14 deaths on study; one related to study drug (lung infection). Of 18 evaluable pts enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 5 best responses of stable disease (SD) were observed. In the AITL cohort (11 evaluable of 16 pts enrolled), a 45% ORR and 73% clinical benefit rate (CBR; 3 CR, 2 PR and 3 SD) was observed. In the wt CXCL12 3'UTR cohort (n=12 evaluable pts), a 42% ORR was observed (3 CR, 2 PR), with 2 of the 3 CRs observed in patients of AITL histology (n=4). A total of 23 AITL subjects were enrolled in the overall study of whom 16 had WES data. A strong association with the activity of tipifarnib was observed in 8 of the 16 (50%) carrying KIR3DL2 gene variants C336R/Q386E: 50% CR rate, 75% ORR, 100% clinical benefit rate. These tumors expressed also very low levels of CXCL5, a ligand for CXCR2, that may mediate resistance to tipifarnib. High Allele Frequency of KIR3DL2 variants predicted CR to tipifarnib treatment (ROC AUC=0.94, p<0.0001) and AITL patients carrying KIR3DL2 gene variants experienced a better outcome with tipifarnib treatment than with prior SOC treatment. While AITL tumors expressed high levels of CXCL12 and responded to tipifarnib, a trend for poor prognosis (22 vs 40 months median OS from diagnosis, HR=1.8, p=0.09) was observed in a series of 50 PTCL subjects treated with SOC therapy. Fifty percent of AITL and 35% of non-AITL samples overexpressed CXCL12. Conclusion The AITL and wt CXCL12 3'UTR cohorts met pre-specified statistical hypotheses supporting proof-of-concept for tipifarnib in PTCL. AITL histology, KIR3DL2 and CXCL12 genotype provided robust tools for the selection/stratification of PTCL subjects treated with tipifarnib. Extended enrollment of AITL patients continues and an update on enrollment and outcomes will be provided at the time of the presentation. Disclosures Sokol: EUSA: Consultancy. Foss:Mallinckrodt: Consultancy; Eisai: Consultancy; Spectrum: Other: fees for non-CME/CE services ; Acrotech: Consultancy; Seattle Genetics: Consultancy, Other: fees for non-CME/CE services ; miRagen: Consultancy. Kim:Donga: Research Funding; Celltrion: Research Funding; J&J: Research Funding; Roche: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; Mundipharma: Research Funding. Jacobsen:Kura Oncology: Research Funding. Advani:Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Kura: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Research Funding; Agensys: Research Funding; Stanford University: Employment, Equity Ownership; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty-Seven: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cell Medica, Ltd: Consultancy; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharma: Research Funding; Millennium: Research Funding. Roncero:Kura Oncology: Research Funding. Terol:Janssen: Consultancy, Research Funding; Roche: Consultancy; Gilead: Research Funding; Astra Zeneca: Consultancy; Abbvie: Consultancy. Domingo-Domenech:Bristol-Myers Squibb: Other: Travel expenses; Roche: Other: Travel expenses; Seattle Genetics: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses. Piris:Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees; Nanostring: Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding. Rodriguez:Kura Oncology: Research Funding. Bolognese:Kura Oncology: Consultancy. Kessler:Kura Oncology: Employment. Mishra:Kura Oncology: Employment. Curry:Kura Oncology: Employment. Kurman:Kura Oncology: Employment. Scholz:Kura Oncology: Employment, Equity Ownership, Patents & Royalties. Gualberto:Kura Oncology: Employment, Equity Ownership, Patents & Royalties.

Abstract The behavioural variant of frontotemporal dementia (bvFTD) is a frequent cause of early-onset dementia. The diagnosis of bvFTD remains challenging because of the limited accuracy of neuroimaging in the early disease stages and the absence of molecular biomarkers, and therefore relies predominantly on clinical assessment. BvFTD shows significant symptomatic overlap with non-degenerative primary psychiatric disorders including major depressive disorder, bipolar disorder, schizophrenia, obsessive-compulsive disorder, autism spectrum disorders and even personality disorders. To date, ∼50% of patients with bvFTD receive a prior psychiatric diagnosis, and average diagnostic delay is up to 5–6 years from symptom onset. It is also not uncommon for patients with primary psychiatric disorders to be wrongly diagnosed with bvFTD. The Neuropsychiatric International Consortium for Frontotemporal Dementia was recently established to determine the current best clinical practice and set up an international collaboration to share a common dataset for future research. The goal of the present paper was to review the existing literature on the diagnosis of bvFTD and its differential diagnosis with primary psychiatric disorders to provide consensus recommendations on the clinical assessment. A systematic literature search with a narrative review was performed to determine all bvFTD-related diagnostic evidence for the following topics: bvFTD history taking, psychiatric assessment, clinical scales, physical and neurological examination, bedside cognitive tests, neuropsychological assessment, social cognition, structural neuroimaging, functional neuroimaging, CSF and genetic testing. For each topic, responsible team members proposed a set of minimal requirements, optimal clinical recommendations, and tools requiring further research or those that should be developed. Recommendations were listed if they reached a ≥ 85% expert consensus based on an online survey among all consortium participants. New recommendations include performing at least one formal social cognition test in the standard neuropsychological battery for bvFTD. We emphasize the importance of 3D-T1 brain MRI with a standardized review protocol including validated visual atrophy rating scales, and to consider volumetric analyses if available. We clarify the role of 18F-fluorodeoxyglucose PET for the exclusion of bvFTD when normal, whereas non-specific regional metabolism abnormalities should not be over-interpreted in the case of a psychiatric differential diagnosis. We highlight the potential role of serum or CSF neurofilament light chain to differentiate bvFTD from primary psychiatric disorders. Finally, based on the increasing literature and clinical experience, the consortium determined that screening for C9orf72 mutation should be performed in all possible/probable bvFTD cases or suspected cases with strong psychiatric features.

AbstractBackgroundGene expression profiling is emerging as a tool for tuberculosis diagnosis and treatment response monitoring, but limited data specific to Indian children and incident tuberculosis infection (TBI) exist.MethodsSixteen pediatric Indian tuberculosis cases were age- and sex-matched to 32 tuberculosis-exposed controls (13 developed incident TBI without subsequent active tuberculosis). Longitudinal samples were collected for ribonucleic acid sequencing. Differential expression analysis generated gene lists that identify tuberculosis diagnosis and tuberculosis treatment response. Data were compared with published gene lists. Population-specific risk score thresholds were calculated.ResultsSeventy-one genes identified tuberculosis diagnosis and 25 treatment response. Within-group expression was partially explained by age, sex, and incident TBI. Transient changes in gene expression were identified after both infection and treatment. Application of 27 published gene lists to our data found variable performance for tuberculosis diagnosis (sensitivity 0.38–1.00, specificity 0.48–0.93) and treatment response (sensitivity 0.70–0.80, specificity 0.40–0.80). Our gene lists found similarly variable performance when applied to published datasets for diagnosis (sensitivity 0.56–0.85, specificity 0.50–0.85) and treatment response (sensitivity 0.49– 0.86, specificity 0.50–0.84).ConclusionsGene expression profiles among Indian children with confirmed tuberculosis were distinct from adult-derived gene lists, highlighting the importance of including distinct populations in differential gene expression models.

Abstract Background: New targeted therapies continue to show improved efficacy in various stages of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), sparing patients from chemoimmunotherapy. However, cure remains elusive. Here, we present a front-line alternative based on a combination of high-dose methylprednisolone (HDMP) and ofatumumab, followed by consolidative therapy with lenalidomide plus ofatumumab. Methods: This is a phase II, single-center study in patients with treatment-naive (TN) CLL/SLL. During the first treatment phase (cycles 1-3) patients received HDMP 1000 mg/m2 IV and ofatumumab 2000 mg (300 mg given week 1 then 2000 mg for a total of 12 doses) IV infusions weekly x 4 doses in cycle 1 of a 28 day cycle, then every 2 weeks for cycles 2 and 3. During the second treatment phase (cycles 4-12), patients received renally adjusted lenalidomide 5-10 mg daily and ofatumumab 2000mg IV once every 8 weeks. Growth factor support was permitted at the discretion of treating physician. Prophylactic medications included allopurinol for tumor lysis syndrome (TLS) 3 days before C1D1 through C1; and trimethoprim/sulfamethoxazole and fluconazole through cycle 4, and acyclovir through C12. Patients received aspirin 81 mg/day as thrombosis prophylaxis while on lenalidomide. Patients were assessed for response by iwCLL 2008 criteria (including imaging assessment) after completion of cycles 3 and 12. The study allowed continuation of lenalidomide if patients achieved complete (CR), partial (PR) response or stable disease (SD). Primary endpoints were efficacy, adverse events (AEs) profile, and time-to-treatment failure (TTF). Results: Between January 2012 and September 2015, the study enrolled a total of 45 patients. Median follow-up was 50.4 (5.6-72.8) months. The median age was 62.6 (48.2-86.1) years. Chromosomal analysis by FISH demonstrated Del17p in 8 (17.8%), Del11q (+/- others, except Del17p) in 10 (22.2%), Trisomy 12 (+/- others, except Del17p and Del11q) in 8 (17.8%), Del13q in 10 (22.2%), no mutations in 9 (20%) patients. The IGHV status was unmutated in 34 (75.6%) cases. Indications to start treatment were: symptomatic lymphadenopathy, symptomatic splenomegaly, anemia, and thrombocytopenia in 5 (11.1%), 10 (22.2%), 12 (26.7%), and 18 (40%), respectively. The median duration of treatment was 35.6 (2.7-66.9) months. Reasons for treatment discontinuation were: progressive disease (PD) in 9 (20%), AEs in 15 (33.3%), transplantation in 3 (6.7%), consent withdrawal in 1 (2.2%), and secondary malignancies in 2 (4.4%) cases. The overall response rates (PR+CR) at 3, 12, 24, 36, and 48 months were 75.6%, 77.8%, 66.7%, 44.4%, and 37.8%, respectively. The CR rates at 3, 12, 24, 36, and 48 months were 2.2%, 11.1%, 20%, 17.8%, and 13.3% respectively. Fifteen patients remain in PR/CR and on treatment at the time of this analysis. The intention-to-treat median TTF was 45.2 (2.9-69.7) months, and was not different among high risk groups such as Del17p, Del11q and/or unmutated IgHV. In patients who discontinued for reasons other than PD the median duration of response without treatment was 30.7 (9.8-69.7) months. Three (6.7%) patients underwent allogeneic hematopoietic cell transplantation after a median of 3 (3 - 4) treatment cycles. Treatment was well tolerated with grade 3/4 infusion reaction in 1 (2.2%) patient. Grade 3/4 treatment-related hematological AEs were neutropenia, thrombocytopenia, and anemia in 33 (73.3%), 5 (11.1%), and 1 (2.2%), respectively. Grade 3/4 infections occurred in 6 (13.3%) patients. No grade 3/4 tumor flares were observed, and there were no cases of TLS or thrombosis. Conclusion: The combination of ofatumumab, HDMP and lenalidomide is effective and well tolerated in treatment-naive CLL/SLL, even when poor prognostic features are present. Disclosures Komrokji: Novartis: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Speakers Bureau. Locke:Novartis Pharmaceuticals: Other: Scientific Advisor; Cellular BioMedicine Group Inc.: Consultancy; Kite Pharma: Other: Scientific Advisor. Kharfan-Dabaja:Seattle Genetics: Speakers Bureau; Incyte Corp: Speakers Bureau; Alexion Pharmaceuticals: Speakers Bureau. Sokol:Spectrum Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy; Mallinckrodt Pharmaceuticals: Consultancy.

Abstract Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a chemokine that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) cohort to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL, age >/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (CXCL12+ cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Ancillary studies are also ongoing to investigate the prognostic value of CXCL12 expression in patients who received standard of care treatment. Results As of 25 July 2018, 34 PTCL pts (13 AITL, 1 ALK- ALCL, 20 PTCL-NOS) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 15 pts in the ongoing AITL histology and CXCL12 cohorts. Median number of prior treatment regimens was 3. The most common treatment-related adverse events (AE) (grade ≥ 3) are hematological, including neutropenia (50%), thrombocytopenia (43%), leukopenia (33%), febrile neutropenia (27%), and anemia (20%). Skin and subcutaneous tissue disorders were reported in 9 pts, 6 of them with AITL histology. One pt with AITL experienced an episode of possible Stevens Johnson Syndrome that resolved with dose discontinuation and did not recur upon re-challenge at one dose level reduction. Of 18 evaluable patients enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 4 best responses of stable disease (SD) were observed. Pre-treatment tumor tissue CXCL12 expression correlated with favorable pt outcomes. In the AITL cohort (10 evaluable pts), 1 PR and 1 SD have been observed so far, with 5 pts pending cycle 2 response evaluation. In the CXCL12+ cohort (n=3 evaluable pts), 1 SD has been observed, with 2 pts pending cycle 2 response evaluation. Plasma levels of CXCL12 decreased over time with tipifarnib treatment. Expression of CXCL12 mRNA and other biomarkers in pre-treatment biopsies of pts in the AITL and CXCL12+ cohorts are being evaluated using RT-PCR assays. In addition, the prognostic value of CXCL12 is being investigated in approximately 100 diagnostic specimens of PTCL pts who received standard therapy. Preliminary data suggest that CXCL12 overexpression is observed in approximately 25% of PTCL and negatively affects pt survival. Conclusion Preliminary activity of tipifarnib was observed in PTCL pts, particularly in those with tumors of AITL histology and high CXCL12 expression and enrollment continues. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Sokol:Mallinckrodt Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy; Spectrum Pharmaceuticals: Consultancy. Jacobsen:Merck: Consultancy; Seattle Genetics: Consultancy. Kim:Takeda: Research Funding; J&J: Research Funding; Mundipharma: Research Funding; Roche: Research Funding; Novartis: Research Funding; Kyowa-Kirin: Research Funding; Celltrion: Research Funding. Foss:Miragen: Consultancy, Speakers Bureau; Spectrum: Consultancy; Seattle genetics: Consultancy; Mallinkrodt: Consultancy. Advani:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kura: Research Funding; Merck: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Regeneron: Research Funding; Janssen: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Cell Medica: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millenium: Research Funding; Agensys: Research Funding; Celgene: Research Funding; Forty Seven: Research Funding; Infinity: Research Funding. Marin Niebla:Amgen: Other: Medical education of Staff, Speakers Bureau; Roche: Consultancy, Other: Medical education of Staff, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Other: Medical education of Staff, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Medical education of Staff, Speakers Bureau. Piris:Kura: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Gilead: Honoraria. Curry:Kura Oncology: Employment, Equity Ownership. Gualberto:Kura Oncology: Employment, Equity Ownership.

Abstract Background: Hereditary transthyretin amyloidosis (hATTR) is a rare, progressive, and fatal disease caused by the buildup of transthyretin-derived amyloid protein in major organs, predominantly affecting the peripheral nerves and heart. Inotersen, a second-generation antisense oligonucleotide targeting TTR mRNA, has shown efficacy and safety in patients with hATTR in a randomized, double-blind, placebo-controlled, phase 3 study, NEURO-TTR (ClinicalTrials.gov, NCT01737398; Benson NEJM 2018). Patients with hATTR amyloidosis who completed the NEURO-TTR study were eligible to receive inotersen for up to 5 years in a phase 3 open-label extension study (ClinicalTrials.gov, NCT02175004). Methods: In NEURO-TTR, patients were randomized 2:1 to receive inotersen (300-mg weekly subcutaneous doses) or placebo. In the open-label extension, patients continued inotersen (inotersen-inotersen) or switched from placebo to inotersen (placebo-inotersen). Evaluations included modified Neuropathy Impairment Score +7 neurophysiologic tests composite score (mNIS+7; higher scores indicate worse neuropathy), Norfolk Quality of Life-Diabetic Neuropathy questionnaire total score (Norfolk QoL-DN; higher scores indicate worse QoL), and adverse events (AEs). Cardiomyopathy (CM) was defined by a diagnosis of hATTR-CM at trial entry or by an interventricular wall thickness of 13 mm or more on transthoracic echocardiography at baseline, as ascertained by a central reader, or no known history of persistent hypertension (systolic blood pressure, ≥150 mm Hg) within 12 months before screening. Results : In the placebo-controlled, double-blind, phase 3 NEURO-TTR study, 112/172 patients were randomized and received inotersen. At baseline, patients were predominantly white (91.9%) males (68.6%) with a mean age of 59.2 years. A total of 67.4% had stage I (ambulatory) and 32.6% had stage II (ambulatory with assistance) disease. Inotersen-treated patients who had stage II disease had a longer duration of disease from diagnosis (40.9 vs 24.8 months, respectively) and from onset (72.6 vs 63.2 months, respectively) of hATTR polyneuropathy symptoms compared with placebo-treated patients who had stage II disease, indicating more advanced disease. A higher proportion of inotersen-treated patients had CM at baseline (67% vs 55%, respectively), and more severe CM, measured by higher NT-proBNP levels and longer duration of disease from hATTR-CM symptom onset, compared with placebo-treated patients. In the phase 3 open-label extension study as of Sept 15, 2017, 134 of 135 patients enrolled received ≥1 dose of inotersen. The mean age was 60.4 years and most patients were male (69.4%). Extended dosing with inotersen up to 27 months continued to improve mNIS+7 and Norfolk QoL-DN in the open-label extension compared to placebo-treated patients at week 66 in the double-blind NEURO-TTR study; mean changes from open-label extension baseline to open-label extension week 52 in the inotersen-inotersen group were 5.1 points for mNIS+7 (vs 25.5 for placebo-treated patients in the double-blind NEURO-TTR study) and 3.9 points for Norfolk QoL-DN (vs 10.7 for placebo-treated patients in the double-blind NEURO-TTR study). Initiation of inotersen in placebo-treated patients (placebo-inotersen) resulted in improvement in mNIS+7 and Norfolk QoL-DN by week 26. Few patients discontinued treatment because of AEs (inotersen-inotersen, 9%; placebo-inotersen, 4%). The rate of treatment-related serious AEs was low in both treatment groups (2% each). There was no evidence of increased risk for grade 4 thrombocytopenia or severe renal events with increased duration of exposure. We will present 2-year follow-up results from the open-label extension study. Conclusions: Results of the open-label extension show continued benefit, measured by mNIS+7 and Norfolk QoL-DN, and confirmed that earlier initiation of treatment is important for optimal clinical outcomes. No new safety concerns were identified. Results from the longer-term follow-up for the open-label extension will further elucidate how inotersen may benefit patients with hATTR amyloidosis. Disclosures Brannagan: Alnylam: Honoraria, Other: Investigator, Speakers Bureau; Ionis: Other: Investigator. Wang:Ionis: Other: Investigator, Speakers Bureau. Coelho:Prothena: Consultancy, Honoraria; Ionis: Consultancy, Other: Investigator; Alnylam: Consultancy, Honoraria, Other: Investigator; Pfizer: Consultancy, Honoraria, Other: Investigator. Waddington Cruz:Ionis: Honoraria; Genzyme/Sanofi: Honoraria; Pfizer: Honoraria. Polydefkis:Pfizer: Honoraria; Alnylam: Honoraria. Dyck:Ionis: Consultancy; Alnylam: Consultancy. Plante-Bordeneuve:Alnylam: Consultancy; Pfizer: Consultancy, Other: reimbursement for travel and meeting; Ionis: Other: reimbursement for travel and meeting. Berk:Ionis: Honoraria, Other: Investigator; Alnylam: Honoraria, Other: Investigator; Pfizer: Other: Investigator. Barroso:Pfizer: Consultancy, Honoraria, Other: Thaos registry, Speakers Bureau; Alnylam: Honoraria, Other: Investigator. Conceição:Alnylam: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy, Honoraria, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau. Hughes:Ionis: Employment. Kwoh:Ionis: Employment. Jung:Ionis: Employment. Guthrie:Akcea: Employment. Pollock:Akcea: Employment. Benson:Ionis: Other: Investigator, Research Funding. Gertz:janssen: Consultancy; Teva: Consultancy; spectrum: Consultancy, Honoraria; Alnylam: Honoraria; Ionis: Honoraria; Amgen: Consultancy; annexon: Consultancy; Prothena: Honoraria; Research to Practice: Consultancy; Apellis: Consultancy; celgene: Consultancy; Abbvie: Consultancy; Medscape: Consultancy; Physicians Education Resource: Consultancy.

Abstract Abstract 259 Despite recent progress, our understanding of the genomic basis of diffuse large B cell lymphoma (DLBCL) is incomplete. We have performed massively parallel whole exome sequencing with deep coverage of 57 primary tumor samples from patients with DLBCL and compared them to matched normal tissue to gain insight into the genetic defects leading to DLBCL. We define genes that are significantly enriched for somatic mutations, and thus, may be drivers of the disease. In addition to identifying genes that are well established to be functionally relevant in DLBCL, such as MyD88, CARD11, EZH2, and BCL2, we also discovered new genes that are significantly mutated that have not been described to play a role in DLBCL previously, such as MLL2, 3 and4 genes and PCLO. One of the challenges for the understanding of DLBCL biology is to determine the relative contribution of different genes with somatic mutations to the pathogenesis of the disease in an individual patient. Identification of functionally relevant mutated genes that only occur in a small number of patients based on prevalence alone may require thousands of patient samples. We therefore devise several strategies to discover genes with a high likelihood of functionally relevant mutations independent of their prevalence. Genes that do not co-occur with other mutated genes in the same patients, i.e. are mutually exclusive, are more likely to represent strong drivers, and to occur early in the development of DLBCL. We determined that TP53, BCL2, PIM1, and CD79B fall into this group. We apply pathway-focused analysis to identify mutated genes with low prevalence that are highly likely to have a functional impact. For instance, we identified G13D mutations in KRAS in two patients, and mutations in BRAF, NOTCH1, SOCS1, and PTEN in other patients that were previously described in other malignancies. These mutated genes are identified as part of significantly enriched gene sets, including the B cell receptor signaling/NFkB pathway, JAK/STAT, and antigen processing gene sets. In addition to these pathways that are important for physiological B cell activation, we find that many histone methyltransferases are enriched as a geneset in addition to MLL2. We identified a number of hotspots that are subject to somatic mutation. Our data imply that many of these hotspots may be targets of activation-induced cytidine deaminase (AID), which is usually involved in somatic hypermutation, suggesting a possible mechanism of how somatic mutation in DLBCL is mediated. In summary, our data define novel genetic defects in DLBCL by whole exome sequencing of 57 patients. Our data suggest that driver mutations may not be randomly distributed across the genome, but may occur in a directed fashion. We identified new genes not previously implicated in DLBCL, and have developed strategies to prioritize mutations that are most likely to be drivers of the disease. Disclosures: No relevant conflicts of interest to declare.