Abstract: Hemophilia A (HA) arises from pathogenic variants in the F8 gene, affecting ~ 1/5000 males. Current factor replacement therapies have limitations, including treatment burden, kinetics (peaks/troughs), morbidity and mortality from breakthrough bleeds, including chronic joint disease, inhibitor development, as well as risk of thrombotic events and coagulation test interference with novel non-factor therapies. Cell therapies with genetically modified human cells expressing hFVIII have been tested as a new potential therapeutic approach. To avoid host cytotoxic immune response, allogeneic cells either need to be physically shielded and/or the host immunosuppressed. Various biomaterials, which can provide a physical barrier from the host immune cells, activate a foreign body response, resulting in pericapsular fibrotic overgrowth (PFO) that significantly limits efficacy and durability of these cell-based therapies. Sigilon utilized a library of proprietary small molecules that avoid PFO when conjugated to alginate biomaterials (Bochenek Nat Biomed Eng 2018) to create a modular, cell-based platform with potential for utilization across a range of chronic diseases, including rare blood disorders. The platform consists of genetically modified allogeneic human cells engineered to produce the therapeutic protein of interest, encapsulated in a two-compartment sphere which supports the function of cells (inner compartment) and shields the cells from the host's immune system and PFO (outer layer) (Barney ASGCT 2020). SIG-001 is a buffered suspension of 1.5 mm alginate spheres encapsulating hFVIII-expressing human cells. SIG-001 can produce functionally active hFVIII in a dose-dependent manner, correct the bleeding phenotype in HA mice, and produce sustained long-lasting hFVIII levels in NSG mice sacrificed at 6 months (Carmona ASH 2019). In preparation for entry into the clinic, SIG-001 was evaluated in mice and non-human primates (NHP). The studies showed no concerning signals in the safety/toxicology profile of SIG-001 (Carmona ISTH 2020). The first-in-human phase 1/2 trial in HA (SIG-001-121, EudraCT 2019-004210-33) will assess the safety, tolerability and preliminary efficacy of SIG-001. This multi-center, open-label study with sequential, dose escalating cohorts, will enroll up to 18 participants (pts), including up to 3 initial pts per cohort and 3 additional pts if cohort expansion is warranted at any dose. A sentinel pt in each cohort will receive a single administration of SIG-001 and be evaluated for at least 4 weeks prior to enrollment of subsequent pts. The next dose level will be initiated following safety review of all pts from the previous dose level(s). The study will include adult males (≥18), with severe or moderately-severe HA (≤2% FVIII activity) who have had ≥150 exposure days to FVIII product(s). The key exclusion criteria include pts with current or past history of FVIII inhibitors. SIG-001 will be administered into the peritoneal cavity using a short laparoscopic procedure, and pts will be followed for 5 years after SIG-001 administration. Primary endpoint of the study is safety, including clinically significant changes in vital signs, clinical laboratory tests, and treatment emergent adverse events compared to baseline. Secondary endpoints include FVIII one-stage and chromogenic activity levels, FVIII inhibitor titers, annualized bleeding rate, and annualized FVIII concentrate use. Exploratory endpoints include QoL metrics, and joint health and physical activity assessments. Results will be analyzed using descriptive statistics. The study will be conducted at sites located in the UK, US and Germany. In conclusion, Sigilon has developed an innovative, modular, scalable, cell-based platform of candidate products for the treatment of chronic diseases, including rare bleeding disorders. The platform was designed to overcome the significant challenges of allogeneic cell therapy, namely immune rejection and PFO. SIG-001 produces hFVIII with in vitro and in vivo functionality. SIG-001-121, first-in-human clinical trial of SIG-001 in HA, is targeted to open in 2020. Disclosures Shapiro: Agios: Research Funding; BioMarin: Research Funding; Bioverativ: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Catalyst BioSciences: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Research Funding; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Glover Blood Therapeutics: Research Funding; Kedrion Biopharma: Research Funding; Novartis: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; OPKO: Research Funding; Octapharma: Research Funding; Pfizer: Research Funding; ProMetic Bio Therapeutics: Consultancy, Research Funding; Sangamo: Research Funding; Sigilon: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk Hemophilia Foundation: Membership on an entity's Board of Directors or advisory committees. Konkle:Sigilon: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; BioMarin: Consultancy; Takeda: Research Funding; Spark: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; CSL Behring: Consultancy; Uniquire: Research Funding; Roche: Consultancy; Baxalta: Research Funding. Croteau:Bayer: Consultancy; Genentech: Consultancy; Pfizer: Consultancy; Novo Nordisk: Research Funding; CSL-Behring: Consultancy; Spark Therapeutics: Research Funding; ATHN: Research Funding; Sigilon Therapeutics: Consultancy; National Hemophilia Foundation: Honoraria; Hemophilia Federation of America: Honoraria. Miesbach:Ablynx: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Aventis: Consultancy; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomarin: Consultancy, Membership on an entity's Board of Directors or advisory committees; Freeline: Consultancy, Membership on an entity's Board of Directors or advisory committees; LEO: Consultancy, Membership on an entity's Board of Directors or advisory committees; LFB: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sobi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sigilon: Consultancy; UniQure: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biotest: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Alexion: Membership on an entity's Board of Directors or advisory committees. Mihova:Sigilon Therapeutics: Current Employment. Rangarajan:Takeda: Other: Conference support, Speakers Bureau; Grifols: Speakers Bureau; Roche: Speakers Bureau; Reliance Life Sciences: Other: Conference support; Sangamo: Research Funding. Pasi:Roche: Honoraria, Other; Sobi: Consultancy, Honoraria, Other; Tremeau: Research Funding; Pfizer: Other; Octapharma: Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia , Speakers Bureau; Novo Nordisk: Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia ; Catalyst Biosciences: Consultancy, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia; Biotest: Consultancy, Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia; Alnylam (Sanofi): Other: Personal fees and nonfinancial support ; Takeda: Consultancy, Honoraria, Other: Personal fees; honoraria as member of scientific advisory boards and symposia ; ApcinteX: Consultancy, Other: Personal fees ; uniQure: Other: Grants and nonfinancial support , Research Funding; BioMarin: Consultancy, Honoraria, Other: Grants, personal fees, and nonfinancial support; honoraria as member of scientific advisory boards and symposia; Sanofi: Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia, Research Funding; Sigilon: Research Funding.

Abstract: Background: Etranacogene dezaparvovec is an investigational gene therapy for hemophilia B (HB) comprising an adeno-associated virus serotype 5 (AAV5) vector containing a codon-optimized Padua variant human factor IX (FIX) gene with a liver specific promoter. In a Phase 2b study, a single dose of etranacogene dezaparvovec provided mean FIX activity of 41.0% sustained at 1yr post-dose in 3 participants (pts). Although most gene therapy clinical studies exclude pts with pre-existing neutralizing antibodies (NAbs) to the capsid serotype, early clinical studies and nonhuman primate data suggest that generally prevalent titers of anti-AAV5 NAbs may not preclude successful transduction with etranacogene dezaparvovec. Aims: A Phase 3, Health Outcomes with Padua gene; Evaluation in Hemophilia B (HOPE-B; NCT03569891) was established to further assess efficacy and safety of etranacogene dezaparvovec in adults with HB with a wide range of pre-existing NAbs to AAV5. Here we report outcomes at 26 weeks (wks). Methods: HOPE-B is a Phase 3, open-label, single-dose, single-arm, multi-national trial in adult males with severe or moderate-severe HB (FIX≤2%). All pts received routine FIX prophylaxis prior to study. Pts were not excluded based on pre-existing NAbs to AAV5. Pts entered a prospective lead-in period of at least 6 months during which bleeding/factor use was monitored, then received a single intravenous dose of etranacogene dezaparvovec (2x1013 gc/kg). Pts will be followed for 5yrs. Primary endpoints comprised FIX activity (one stage) at 26 and 52wks after dosing and 52wk annualized bleeding rate. For pts with no clean post-treatment FIX samples (≥10d post exogenous FIX), factor activity was imputed as baseline value based on historic disease severity. Secondary endpoints include factor replacement use, adverse events (AEs), and reactive use of corticosteroids. Results: 75 pts were screened, of whom 67 entered lead-in. 54 pts were dosed (44 severe, 10 moderately severe HB) and completed 26wks of follow-up. Mean age (±SD) was 41.5 (15.8) yrs. 38/54 pts (70.4%) had bleeds (n=123) during the lead-in despite prophylaxis, and 23/54 (42.6%) had NAbs to AAV5 at baseline (max titer: 3212.3). Following treatment, FIX activity increased rapidly to a mean (SD; min,max) of 37.2% (±19.6; 1.0, 97.1) at wk26, representing a mean (SD; min,max) change from baseline of 36.0% (±19.7; 0, 96.1 p & lt;0.0001, confirmed by per-protocol sensitivity analysis). No correlation of pre-existing NAbs with FIX activity was identified up to a titer of 678.2; n=52, R2 = 0.078); a single pt had a NAb titer of 3212.3 and did not respond. In addition to this pt, one other pt received a partial dose and remained on prophylaxis; all other pts (96.3%) successfully discontinued routine prophylaxis. 39/54 (72.2%) pts reported 0 bleeds in the first 26wks post-treatment; 15 pts reported a total of 21 bleeds. Mean (SD) annualized FIX consumption (IU/yr/pt) was 292,304 (±171,079) during lead-in, decreasing to 12,622 (±36,466) at wk26 (96.0% reduction, N=54). Overall, 37/54 (68.5%) pts had any treatment-related AE post-treatment, the majority of which were mild (81.5%). No deaths occurred and no treatment-related SAEs were reported. 7 pts had infusion-related reactions; the infusion was discontinued in 1 pt. Treatment-related elevations in liver enzymes were reported in 9 pts and received steroids per protocol. All discontinued steroid use prior to wk26 and FIX activity was preserved in the mild range. In addition to these, the most frequent treatment-related AEs were headache (13.0%) and influenza-like illness (13.0%). No inhibitors to FIX were reported. No relationship between safety and NAbs was observed. Conclusions: The first co-primary endpoint of this study was met. This is the first report of a Phase 3 study in HB and the largest gene therapy trial cohort to date. Following a single dose of etranacogene dezaparvovec, FIX activity increased, without the need for prophylactic immunosuppression, into the mild-to-normal range at 26wks in pts with severe/moderately severe HB. Importantly, this included pts with titers of pre-existing anti-AAV5 NAbs. Pts were able to discontinue prophylaxis and bleeding was abolished in the majority. The safety profile was consistent with early phase AAV5 studies and together these data support a favorable safety and efficacy profile for etranacogene dezaparvovec Disclosures Pipe: HEMA Biologics: Consultancy, Other; Catalyst Biosciences: Consultancy; CSL Behring: Consultancy; ApcinteX: Consultancy; Bayer: Consultancy, Other: Contracted Research; BioMarin: Consultancy, Other: Contracted Research; Takeda: Consultancy; uniQure: Consultancy, Other; Siemens: Other; Pfizer: Consultancy; Freeline Therapeutics: Consultancy, Other: Contracted Research; Novo Nordisk: Consultancy, Other: Contracted Research; Roche/Genentech: Consultancy, Other: Contracted Research; Sangamo Therapeutics: Consultancy; Sanofi Genzyme: Consultancy, Other; Spark Therapeutics: Consultancy. Recht:CSL Behring: Consultancy, Other: personal fees; Genentech: Consultancy, Other: personal fees, Research Funding; Pfizer: Consultancy, Other: personal fees, Research Funding; BioMarin: Research Funding; Takeda: Consultancy, Other: personal fees, Research Funding; uniQure: Consultancy, Other: personal fees, Research Funding; Novo Nordisk: Consultancy, Other: personal fees, Research Funding; Spark: Research Funding; Bayer: Research Funding; Grifols: Research Funding; Hema Biologics: Consultancy, Research Funding; LFB: Research Funding; Octapharma: Research Funding; Catalyst Biosciences: Consultancy; Kedrion: Consultancy; Sanofi: Consultancy, Research Funding. Key:Uniqure: Consultancy; Grifols: Research Funding; Takeda: Research Funding; Novo Nordisk: Other: Chair of Grants Committee. Leebeek:Shire/Takeda: Research Funding; uniQure: Consultancy; Shire/Takeda: Consultancy; BioMarin: Consultancy; SOBI: Other: Travel grant; Roche: Other: DSMB member for a study; CSL Behring: Research Funding. Castaman:Bayer, Roche, Sobi, Grifols, Novo Nordick, Werfen, Kedrion: Consultancy, Honoraria, Speakers Bureau; CSL Behring, Pfizer, Sobi: Research Funding; Ablynx, Alexion, Bayer, Takeda, CSL Behring, Novo Nordisk, Pfizer, Roche,Sanofi, SOBI, uniQure: Membership on an entity's Board of Directors or advisory committees. Lattimore:uniQure: Other: Study Steering Committee member. Van Der Valk:Baxalta: Research Funding. Peerlinck:Bayer: Consultancy, Research Funding; CSL Behring: Consultancy, Research Funding; NovoNordisk: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Roche: Research Funding; Sobi: Consultancy; Takeda: Consultancy, Research Funding. Coppens:Roche: Research Funding; Portola/Alexion: Research Funding; Sanquin Blood Supply: Research Funding; uniQure: Research Funding; NovoNordisk: Consultancy; Pfizer: Consultancy; Sobi: Consultancy; Medcon International: Consultancy; MEDtalks: Consultancy; Bayer: Consultancy, Research Funding; CSL Behring: Consultancy, Research Funding; Daiichi Sankyo: Research Funding. O'Connell:uniQure: Consultancy; F. Hoffmann-La Roche Ltd, Novo Nordisk, SOBI: Speakers Bureau; SOBI: Research Funding. Pasi:Sanofi: Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia, Research Funding; BioMarin: Consultancy, Honoraria, Other: Grants, personal fees, and nonfinancial support; honoraria as member of scientific advisory boards and symposia, Research Funding; uniQure: Other: Grants and nonfinancial support , Research Funding; ApcinteX: Consultancy, Other: Personal fees ; Takeda: Consultancy, Honoraria, Other: Personal fees; honoraria as member of scientific advisory boards and symposia ; Biotest: Consultancy, Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia; Catalyst Biosciences: Consultancy, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia; Novo Nordisk: Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia ; Octapharma: Honoraria, Other: Personal fees and nonfinancial support; honoraria as member of scientific advisory boards and symposia , Speakers Bureau; Roche: Honoraria, Other; Sobi: Consultancy, Honoraria, Other; Tremeau: Consultancy. Kampmann:Uniqure: Research Funding, Speakers Bureau; Shire Pharmaceuticals: Speakers Bureau. Meijer:Pfizer: Research Funding; Sanquin: Speakers Bureau; Bayer: Speakers Bureau; Sanquin: Research Funding; Bayer: Research Funding; Boehringer Ingelheim: Speakers Bureau; BMS: Speakers Bureau; Aspen: Speakers Bureau; Uniqure: Consultancy. von Drygalski:Biomarin: Consultancy; Bioverativ/Sanofi Genzyme: Consultancy; NovoNordisk: Consultancy; Pfizer: Consultancy; uniQure: Consultancy; Hematherix Inc.: Membership on an entity's Board of Directors or advisory committees. Young:Genentech/Roche, Grifols, and Takeda: Research Funding; BioMarin, Freeline, Genentech/Roche, Grifols, Kedrion, Novo Nordisk, Sanofi Genzyme, Spark, Takeda, and UniQure: Honoraria; Bayer, CSL Behring, Freeline, UniQure: Consultancy. Hermans:WFH: Other; EAHAD: Other; LFB: Consultancy, Speakers Bureau; CSL Behring: Consultancy, Speakers Bureau; CAF-DCF: Consultancy, Speakers Bureau; Biogen: Consultancy, Speakers Bureau; Sobi: Consultancy, Research Funding, Speakers Bureau; Shire, a Takeda company: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Research Funding, Speakers Bureau; Novo Nordisk: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Octapharma: Consultancy, Speakers Bureau; Kedrion: Speakers Bureau. Astermark:Bayer, CSL Behring, Novo Nordisk, Octapharma, Roche, Sobi, Spark, Takeda, uniQure: Consultancy; uniQure: Research Funding. Klamroth:Bayer: Consultancy, Research Funding, Speakers Bureau; Biomarin: Consultancy, Research Funding, Speakers Bureau; CSL Behring: Research Funding, Speakers Bureau; Novo Nordisk: Consultancy, Research Funding, Speakers Bureau; Octapharma: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; Roche/Chugai: Consultancy, Speakers Bureau; Takeda/Shire: Consultancy, Research Funding, Speakers Bureau; Sobi: Consultancy, Speakers Bureau; Biotest: Speakers Bureau; LEO: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Lemons:uniQure: Research Funding. Visweshwar:Biogen Idec: Membership on an entity's Board of Directors or advisory committees. Escobar:Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; National Hemophilia Foundation: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biomarin, Genetech/Roche, CSL Behring, Kedrion, Magellan Healthcare: Honoraria. Gomez:Global Blood Therapeutics: Speakers Bureau. Kruse-Jarres:CSL Behring, Genentech, Inc., Spark: Research Funding; Biomarin, Chugai Pharmaceutical Co., CSL Behring, CRISPR Therapeutics, Genentech, Inc.: Honoraria; F. Hoffmann-La Roche Ltd: Speakers Bureau; Biomarin, Chugai Pharmaceutical Co., CSL Behring, CRISPR Therapeutics, Genentech, Inc.: Consultancy. Kotowski:uniQure: Research Funding. Quon:Orthopaedic Institute for Children: Current Employment; Bayer: Honoraria; Biomarin: Honoraria, Speakers Bureau; Bioverativ/Sanofi: Honoraria, Speakers Bureau; Genentech, Inc./F. Hoffmann-La Roche Ltd: Honoraria, Speakers Bureau; Novo Nordisk: Honoraria, Speakers Bureau; Octapharma: Honoraria; Shire/Takeda: Speakers Bureau. Wang:Bayer: Honoraria; Takeda: Honoraria; Genentech: Honoraria; Biomarin: Honoraria; CSL Behring: Honoraria; Bioverativ Inc: Honoraria; Catalyst Biologics: Consultancy; NovoNordisk: Consultancy; Hema biologics / LFB: Consultancy. Wheeler:Takeda: Membership on an entity's Board of Directors or advisory committees; uniQure: Membership on an entity's Board of Directors or advisory committees; Biomarin: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees. Sawyer:uniQure: Current Employment, Current equity holder in publicly-traded company. Verweij:uniQure: Current Employment. Colletta:uniQure: Current Employment. Bajma:uniQure: Current Employment. Gut:uniQure: Current Employment. Miesbach:Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomarin: Consultancy, Membership on an entity's Board of Directors or advisory committees; Freeline: Consultancy, Membership on an entity's Board of Directors or advisory committees; LFB: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; uniQure: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biotest: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. OffLabel Disclosure: Etranacogene dezaparvovec is an investigational gene therapy

Abstract: The antiphospholipid syndrome (APS) is one of the most common acquired causes of thrombosis on the venous or arterial site. The initial type of the thrombosis appears to be the most likely type of event to recur. In general, APS patients present more common venous thrombosis, especially deep vein thrombosis of the legs. Arterial thromboses are less common and mostly manifest with ischemia or infarction. It is not clear whether a combination of phospholipid antibodies or the additional presence of lupus anticoagulants in patients with anticardiolipin antibodies increase the risk of manifestation of APS. Methods: We investigated retrospectively 300 patients with elevated aCL antibodies. IgG and IgM aCL antibodies were tested by enzyme-linked immunosorbent assay (ELISA). LA were tested by more than 2 different methods according to the proposed criteria of the SSC of the ISTH. Results: Of these patients, 61 % suffered from manifestations of APS, 35 % from venous and 28 % from arterial thrombosis, 7 % of the patients had abortions. In 39 % no thromboembolic disease was found. The coincidence of venous and arterial thrombosis was found in 25/300 (8 %) of the patients. An increased titer of IgG aCL was found in 135 of 300 patients (45 %, median 49 GPL-U/ml, normal range: - 11,3 GPL-U/ml), and an increased titer of IgM aCL in 260 patients (87 %, median 13 MPL-U/ml, normal range: 5,6 MPL-U/ml). Lupus anticoagulants were additionally detected in 130/300 patients (43 %). The rate of clinical manifestations did not differ between LA-positive patients (78 of 130 patients, 60 %) and LA-negative patients (105 of 170, 62 %) patients with elevated aCL antibodies. Regarding the patients with the coincidence of venous and arterial thrombosis, we found a significantly higher rate of positive lupus anticoagulants than in the patients with APS manifestation of one site only (17/25 vs. 113/275, p 〈 0.05, OR 3.04; 95 % CI 1.31 – 7.06). An elevation of IgG-aCL titres were more frequently found, too. Table 1: Characteristics of the patients with a coincidence of venous and arterial thrombosis compared to patients with thrombosis of one site only Conclusion: The additional presence of lupus anticoagulants in patients with anticardiolipin antibodies identifies a group of patients with high risk of recurrent manifestations of the antiphospholipid syndrome. Particularly the risk of manifestation of both, arterial and venous thrombosis in these patients should be early recognized to initiate a careful follow-up and antithrombotic therapy in these patients. Venous and Arterial Thrombosis Thrombosis of One Site No APS Manifestation n 25/300 (8 %) 157/300 (59 %) 118/300 (39 %) Age (yrs) median 48.5 50 46 Sex (F/M) 17/8 (2.1) 62/157 (2.1) 51/118 (2.3) LA 17/25 (68 %) 62/157 (39 %) 51/118 (43 %) IgG-aCL 15/25 (60 %) 73/157 (46 %) 47/118 (40 %) median titre 108 GPL 87 GPL 37 GPL IgM-aCL 24/25 (96 %) 129/157 (82 %) 104/118 (88 %) median titre 13 MPL 14 MPL 14 MPL

Abstract: Abstract 3321 Aim: Age dependent variations of coagulation factors are well known in the general population. This investigation studies the long/term, age-dependent variations of coagulation factors in patients with hemophilia A (HA) and von Willebrand disease (VWD) in correlation to the co-morbidity. Methods: In this retrospective, single center cohort study, the median observation time was 14 years (5–43). Technical equipment did not change during the observation time. We compared FVIII:C, vWF:Ag and vWF:RCo levels of 65 pt with HA (mild n=48, moderate n=10, severe n=7; median age 28 years at first blood withdrawal, 47 years at last withdrawal), 84 pt with VWD (54w, 30m; type 1 n=57, type 2 n=15, type 3 n=10, type not specified n=2; median age 30,5 years at first blood withdrawal, 47,5 years at last withdrawal) and 23 conductors of HA (median age 36 years at first blood withdrawal, 42 years at last withdrawal). Results: FVIII:C levels collected from pt with mild HA displayed a significant median increase of 6,5% (−15 – 31%) with proceeding age from 14,5% (5,3 – 47%) to 19% (4,8 – 76%) (p=0,001335). For pt with moderate HA a non significant median increase of 1,05% (−3,6 – 16%) from 4,95% (2,8 – 11%) to (3 – 20%) was found. Eight pt showed FVIII:C levels during the last blood withdrawal, that indicated a change of severity from moderate to mild HA. Conductors of HA showed a non significant median increase of 8% (−52 – 95%) from 59% (21 – 118%) to 55% (33 – 145%). The course of FVIII:C levels in pt with severe HA did not vary. FVIII:C levels of pt with mild HA and conductors of HA showed a non significant tendency to higher increase at higher age. Also, a stronger increase at higher initial FVIII:C levels (assessed at first blood withdrawal) was found. Neither cardiovascular diseases nor hepatitis status correlated significantly to the age dependant increase of FVIII:C. FVIII:C levels of patients with VWD displayed an age-dependant significant median increase of 7,5% (−39 – 54%) from 62% (1 – 98%) to 68% (1 – 138%) (p = 0.010038). Additionally, a significant median increase of vWF:Ag of 7% (−61 – 67%) from 49% (0 – 112%) to 57% (3 – 105%) (p = 0.000072) and a non significant median increase of VWF:RCo of 2,5% (−42 – 82%) from 50% (0 – 90%) to 49,5% (0 – 143%) (p = 0.867876) were observed. The type of VWD (1, 2, 3), BMI, smoking status, treatment preparation, and co-morbidity (CHD, thrombosis, hypertonus, malignant disease and smoking) did not correlate to the observed increases. Conclusion: Pt with mild HA/VWD showed a significant increase of FVIII:C levels parallel to the ageing process. This increase was not significant in pt with moderate HA and conductors of HA. The course of FVIII:C levels in pt with severe HA did not vary. Pt with VWD additionally showed a significant increase of VWF:Ag and a non significant increase of VWF:RCo at proceeding age. No correlation to lifestyle factors or co-morbidity could be found. Disclosures: No relevant conflicts of interest to declare.

Abstract: The congenital dysfibrinogenemia is a rare clotting disorder which is based on a structural defect in the fibrinogen molecule. Approximately 350 cases of unrelated families with dysfibrinogenemia have been reported. Of these, the structural defects have been determined in nearly 170 families. Patients and methods: We describe the clinical manifestations in 50 patients from 19 families from Frankfurt. Up to now the underlying structural defect could be found in 43/50 (86 %) of the patients and 14/19 (74 %) of the families (Galanakis, New York, von Depka, Hannover). Results: In 19 families, 50 patients were found with dysfibrinogenemia (52% female, age median: 52 years-old, 9 - 89 years old). The fibrinogen level, according to Clauss decreased in median with 51 mg% (15 – 86 mg/dl, norm: 150 – 450 mg/dl). The determination of the other fibrinogen levels resulted in the normal range. Fibrinogen according to Schulz: 240 mg/dl, immunological fibrinogen: 244 mg/dl. The Reptilase time was prolonged to 55 sec (median, norm: − 20 sec.). 50% of the patients stated a distinct bleeding tendency and mostly a tendency for haematoma (59%) and secondary haemorrhaging (45%). 13 patients had a thrombotic disease, of which 80% were arterially caused. 12 % of the patients stated a tendency for bleeding as well as for thrombosis. 19% of the patients had miscarriages, partly recurrent and 18/50 (36 %) of the patients were asymptomatic. Furthermore, it was observed that the clinical symptoms are often similar in the affected families. By administration of fibrinogen concentrates, the pregnancy in 4 patients who suffered from abortions in the first weeks of pregnancy resulted in healthy children. Fibrinogen was administered from the beginning of the pregnancy till the delivery (aiming fibrinogen levels of Clauss up to 100 mg%). In 11 of the families, an Aalpha 16 Arg-Cys mutation was found. In the other three families there were found gamma mutations, e.g., gamma 356 Ala-Thr, gamma 318–319 del and gamma 318 Ap-Gly. The clinical manifestations in the families with Aalpha 16 Arg-Cys mutation were bleeding (65 %), thrombosis (22 %) and abortions (16 %). 25 % were asymptomatic and 12 % of the patients experienced both, bleeding and thrombosis. Conclusion: The investigations of the Frankfurt patient group with dysfibrinogenemia showed a high rate of clinical manifestations, mostly the tendency for haematoma and secondary haemorrhaging. The tendency for thrombosis is concerned rather with the arterial vessels. The high tendency for miscarriage is striking, which makes the administration of fibrinogen concentrate during pregnancy necessary. The most common found fibrinogen mutation was at the Aaplha chain in position 16. In patients with this mutation mostly both, bleeding and thrombosis occurred. Thus, management of patients with this mutation may be complicated by the variablility of clinical manifestations of congenital dysfibrinogenemia.

Abstract: Acquired hemophilia A (AHA) is a rare autoimmune disorder caused by neutralizing autoantibodies against coagulation factor VIII (FVIII:C). Immunosuppressive treatment may result in remission of disease over a period of days to months. Until remission, patients are at high risk of bleeding and complications from immunosuppression. Prognostic parameters to predict remission and the time needed to achieve remission could be helpful to guide treatment intensity, but have not been established so far. GTH-AH01/2010 was a prospective multicenter cohort study using a standardized immunosuppressive treatment protocol. The primary study endpoint was time to achieve partial remission (PR, defined as FVIII:C activity 〉 50 IU/dl after cessation of any hemotherapy for 〉 24h, and no active bleeding). Secondary endpoints were time to achieve complete remission (CR, defined as PR plus negative FVIII:C inhibitor, steroid tapered to 〈 15 mg/d prednisolone, and cessation of any other immunosuppressive treatment), and overall survival (OS). Enrolment was strictly prospective and only allowed within 7 days of starting immunosuppression. Outcome data were recorded in all patients enrolled. The treatment protocol consisted of prednisolone (100 mg/d from day 1 to the day of PR, then tapered down to 〈 15 mg/d over 5 weeks), oral cyclophosphamide (150 mg/d, from day 21-42, unless PR was achieved), and rituximab (375 mg/m2 weekly for 4 weeks starting on day 43, unless PR was achieved). If AHA was first diagnosed in patients previously on prednisolone 〉 15 mg/d, or equivalent, they received prednisolone (100 mg/d) and rituximab from day 1. If cyclophosphamide was contraindicated, patients received prednisolone (100 mg/d) and rituximab from day 21. One hundred twenty-four patients from 21 treatment centers in Germany and Austria were enrolled between April 2010 and April 2013 (36 months). The patients from two centers not compliant with the treatment protocol were excluded (N=18), as were patients in whom AHA was not confirmed (N=2) or follow-up was too short at the time of this analysis (N=7). The remaining 97 patients from 17 centers were followed for a median of 256 days (interquartile range [IQR] 84-561). Median age was 74 years (IQR 64-82). AHA was associated with other autoimmune disorders (19%), malignancy (12%), pregnancy or puerperium (5%), but was most often idiopathic (66%). The median FVIII:C activity at baseline was 1 IU/dl (IQR 〈 1-3), and the median inhibitor titer was 20 BU/ml (IQR 7.7-78). PR and CR were achieved after a median time of 35 and 102 days, respectively. Patients achieving PR prior to day 21 (N=22) compared with patients not achieving PR within 21 days (N=75) had a higher baseline FVIII:C activity (median 3 vs. 〈 1 IU/dl, p 〈 0.01) and a lower FVIII:C inhibitor (median 12 vs. 29 BU/ml, p 〈 0.05). Multivariate analysis with adjustment for age, sex, underlying disorder, and WHO performance status on admission demonstrated that baseline FVIII:C activity ( 〈 1 IU/dl vs. 〉 =1 IU/dl) had a strong impact on the time to achieve PR (HR 2.76 [95% confidence interval 1.73-4.42] , p 〈 0.001) and CR (HR 2.36 [1.34-4.14], p 〈 0.01). Baseline FVIII:C activity was also a predictor of PR and CR when other cutoffs were used (2 or 3 IU/dl instead of 1 IU/dl), or when it was analyzed as a continuous variable in Cox regression analysis. In contrast, FVIII:C inhibitor titer assessed by the local laboratory did not affect time to PR or CR significantly. OS after 300 days, estimated by the Kaplan Meier method, was 69%. Age, WHO performance status, and FVIII:C activity at baseline were independent predictors of OS. In summary, GTH-AH 01/2010 is the largest prospective study of patients with AHA treated according to a standardized protocol. The study demonstrated a robust effect of baseline FVIII:C activity on the time needed to achieve PR and CR. Baseline FVIII:C activity, together with age and performance status, also affected OS. Therefore, baseline FVIII:C activity may be considered to guide individually tailored immunosuppression in future studies. Disclosures: Tiede: Baxter: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Biotest: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novo Nordisk: Consultancy, Honoraria, Research Funding; Biogen Idec: Consultancy; CSL Behring: Consultancy, Honoraria, Research Funding. Off Label Use: Prednisolone, cyclophosphamid, and rituximab for immunosuppression in acquired hemophilia. Klamroth:Bayer: Honoraria, Research Funding; Baxter: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Novo Nordisk: Honoraria, Research Funding. Gottstein:Novo Nordisk: Honoraria; Baxter: Honoraria. Holstein:Baxter: Honoraria, Speakers Bureau. Scharf:CSL Behring: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Biotest: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria; Baxter: Consultancy, Honoraria, Research Funding. Huth-Kühne:SRH Kurpfalz Hospital and Hemophilia Center: Consultancy, Employment, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Greil:Roche: Consultancy, Honoraria, Research Funding. Miesbach:Novo Nordisk: Consultancy, Honoraria, Research Funding; Baxter: Consultancy, Honoraria, Research Funding. Trappe:Roche: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau, Travel Other; AMGEN: Research Funding, Travel, Travel Other; CSL Behring: Honoraria, Research Funding, Speakers Bureau, Travel, Travel Other; Mundipharma: Research Funding, Travel, Travel Other; Takeda: Consultancy, Research Funding, Travel Other; Novartis: Consultancy, Research Funding, Travel, Travel Other; Novartis: Research Funding, Travel Other; Cellgen: Travel, Travel Other. Knoebl:Novo Nordisk: Consultancy, Honoraria; Baxter: Consultancy, Honoraria.

Abstract: Gene therapy has been successfully used in a research setting in a limited number of patients with severe haemophilia B, primarily using vectors based on adeno-associated virus (AAV) serotype 2 and 8. Several research groups and companies are exploring new developments to improve current treatment strategies to eventually make gene therapy available for a larger number of patients. Pre-existing immunity to AAV capsid proteins may limit the availability of such therapies to small sub-groups of patients. A low prevalence of natural neutralizing antibodies against AAV5 compared with other serotypes has been demonstrated (Calcedo et al., Clin Vaccine Immunol 2009, 18:1586-1588). We use a recombinant AAV5 containing the codon optimized human factor IX gene (AAV5-hFIX), using a baculovirus production process that allows commercial scale manufacturing of the AAV5-hFIX drug product. Human FIX expression levels in macaques treated i.v. with AAV5-hFIX at a dose of 5 × 10^12 gc/kg were high enough to expect therapeutic effect on the haemophiliac phenotype in haemophilia B patients. Such levels were achieved in humans during AAV8-hFIXco clinical study (Nathwani et al., NEJM 2011, 365:2357-2365). hFIX levels in dose-escalating GLP toxicity studies in cynomolgus monkeys and mice showed linear dose responses using doses up to 1 × 10˄14 and 2.3 × 10^14 cg/kg, respectively, and no specific safety concerns. In human studies with AAV5 containing the human porbilinogen deaminase (PBGD) gene, administered in doses up to 2 x 10^13 gc/kg to patients with acute intermittent porphyria, no safety concerns were raised (D’Avola et al., ASGCT, Washington DC, 2014). Importantly, in this study no liver enzyme perturbations were observed following administration of AAV5. The primary objective of the proposed study is to investigate the safety of systemic administration of AAV5-hFIX to adult patients with severe or moderately severe haemophilia B. The multicentre trial has an open-label, uncontrolled, single-dose, dose-ascending design and consists of two cohorts. The study population consists of male patients, aged ≥18 years, with severe or moderately severe haemophilia B and a severe bleeding phenotype [i.e. known FIX deficiency with plasma FIX activity level 〈 1% (severe), or plasma FIX activity level ≥1% and ≤2% (moderately severe) and currently on prophylactic FIX replacement therapy for a history of bleeding, or currently on on-demand therapy with a current or past history of frequent bleeding defined as four or more bleeding episodes in the last 12 months, or chronic haemophilic arthropathy. Patients should have had more than 150 previous exposure days of treatment with FIX protein. Subjects are allocated to one of two cohorts with the following planned dose levels: Cohort 1 (5 subjects) with AAV5-hFIX 5.0 × 10^12 gc/kg and Cohort 2 (5 subjects) with AAV5-hFIX 2.0 × 10^13 gc/kg. Key efficacy assessments include factor IX plasma levels, the need for FIX replacement therapy, incidence of spontaneous bleedings and health-related quality of life measurements. In conclusion, AAV5-hFIX produced in commercial scale represents a novel approach to gene therapy of haemophilia B. Disclosures Miesbach: uniQure: Consultancy; Bayer: Research Funding; Baxter: Research Funding; CSL Behring: Research Funding; Biotest: Research Funding; Octapharma: Research Funding. Meyer:uniQure B. V.: Employment. Nijmeijer:uniQure B. V.: Employment. Salmon:uniQure B. V.: Employment. Grosios:uniQure B. V.: Employment. Petry:uniQure B. V,: Employment. Leebeek:uniQure B. V.: Consultancy; CSL Behring: Research Funding; Baxter: Research Funding.