Forum on: the role of recombinant factor VIII in children with severe haemophilia A

Summary. The development of recombinant FVIII (rFVIII) products, fuelled by the need for improved safety of treatment arising from the dramatic widespread blood‐borne virus transmission in the 1970–1980s revolutionized the care of children with haemophilia A over the last two decades. The larger availability of perceived safer replacement therapy associated with the introduction of rFVIII products reassured the haemophilia community and there was a strong push in some Western countries to treat haemophilic children only with rFVIII. Moreover, this significantly contributed in the 1990s to the diffusion outside Northern Europe of prophylactic regimens implemented at an early age to prevent bleeding and the resultant joint damage (i.e. primary prophylaxis), together with the possibility of home treatment. These changes led to a substantial improvement of the quality of life of haemophilic children and of their families. The general agreement that primary prophylaxis represents the first‐choice treatment for haemophilic children has been recently supported by two randomized controlled trials carried out with rFVIII products, providing evidence on the efficacy of early prophylaxis over on‐demand treatment in preserving joint health in haemophilic children. However, the intensity and optimal modalities of implementation of prophylaxis in children, in particular with respect to the issue of the venous access, are still debated. A number of studies also supports the role of secondary prophylaxis in children, frequently used in countries in which primary prophylaxis was introduced more recently. With viral safety now less than an issue and with the more widespread use of prophylaxis able to prevent arthropathy, the most challenging complication of replacement therapy for children with haemophilia remains the risk of inhibitor development. Despite conflicting data, there is no evidence that the type of FVIII concentrate significantly influences the complex multifactorial process leading to anti‐FVIII alloantibodies, whereas other treatment‐related factors are likely to increase (early intensive treatments due to surgery or severe bleeds) or reduce (prophylaxis) the risk. Although the optimal regimen is still uncertain, eradication of anti‐FVIII antibodies by immune tolerance induction (ITI), usually with the same product administered at inhibitor detection, should be the first‐choice treatment for all patients with recent onset inhibitors. This issue applies particularly to children, as most patients undergo ITI at an early age, when inhibitors usually appear. The availability of a stable and long‐lasting venous access represents a leading problem also in this setting. These and other topics concerning rFVIII treatment of haemophilic children were discussed in a meeting held in Rome on 27 February 2008 and are summarized in this report.     

Prevalence of IgG antibodies to human parvovirus B19 in haemophilia children treated with recombinant factor (F)VIII only or with at least one plasma-derived FVIII or FIX concentrate: results from the French haemophilia cohort

Human parvovirus B19 (B19) has been transmitted by some brands of virally attenuated plasma-derived factor VIII (FVIII) or IX (FIX) concentrates. To quantify the differences of human parvovirus B19 risk transmission between albumin-stabilized recombinant factor and plasma-derived factor, we studied the prevalence of IgG antibodies to B19 (anti-B19) in 193 haemophiliac children between 1 and 6-years of age who had previously been treated with albumin-stabilized recombinant FVIII only (n = 104), and in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates (n = 89). Association between the prevalence of anti-B19 and the treatment group was analysed using multivariate logistic regression. Age, severity and type of haemophilia, number of cumulative days of exposure to factor VIII or IX, previous history of red blood cells or plasma transfusion were considered as potential confounding variables. A higher prevalence of anti-B19 was found in children previously treated with solvent/detergent high-purity non-immunopurified and non-nanofiltered FVIII or IX concentrates than in children treated with albumin- stabilized recombinant FVIII only (OR: 22.3; CI: 7.9-62.8), independently of the other factors studied.     

Real-world safety and effectiveness of recombinant porcine sequence factor VIII in acquired haemophilia A: A non-interventional,post-authorization safety study

Introduction

Recombinant porcine factor VIII (rpFVIII, susoctocog alfa) is indicated for the treatment of bleeding episodes in adults with acquired haemophilia A (AHA).

Aim

To provide long-term real-world safety and effectiveness data for rpFVIII in the management of AHA bleeding episodes.

Methods

US PASS (NCT02610127) was a multicentre, uncontrolled, open-label, post-marketing safety surveillance study conducted in adults with AHA. Data were collected retrospectively or prospectively for 180 days after rpFVIII treatment. The primary outcome was the incidence of treatment-related serious adverse events (SAEs). Secondary outcomes included haemostatic effectiveness of rpFVIII and rpFVIII utilization.

Results

Fifty-three patients were enrolled from December 2015 to June 2019 (prospective, n = 30; retrospective, n = 23). Six patients experienced seven treatment-related SAEs (incidence 12.0%). The most common treatment-related SAE was FVIII inhibition (inhibiting antibodies to rpFVIII; incidence 8.0%, 95% CI: 2.2–19.2). Five patients reported seven thromboembolic events; one was an SAE and possibly related to rpFVIII. Of bleeding events treated with rpFVIII, 80.3% (57/71) of bleeds resolved with rpFVIII. The median (range) dose of rpFVIII per infusion was 50 (10–300) units/kg, with a median (range) of 6.0 (1–140) infusions and a median (range) time from bleed onset to bleed resolution of 14.0 (2.0–132.7) days.

Conclusion

In this real-world study of rpFVIII for AHA, no new safety signals were identified compared with previous clinical trial findings. Eighty percent of bleeds resolved with rpFVIII treatment.     

Validation of the manufacturing process used to produce long‐acting recombinant factor IX Fc fusion protein

Recombinant factor IX Fc (rFIXFc) fusion protein is the first of a new class of bioengineered long‐acting factors approved for the treatment and prevention of bleeding episodes in haemophilia B. The aim of this work was to describe the manufacturing process for rFIXFc, to assess product quality and to evaluate the capacity of the process to remove impurities and viruses. This manufacturing process utilized a transferable and scalable platform approach established for therapeutic antibody manufacturing and adapted for production of the rFIXFc molecule. rFIXFc was produced using a process free of human‐ and animal‐derived raw materials and a host cell line derived from human embryonic kidney (HEK) 293H cells. The process employed multi‐step purification and viral clearance processing, including use of a protein A affinity capture chromatography step, which binds to the Fc portion of the rFIXFc molecule with high affinity and specificity, and a 15 nm pore size virus removal nanofilter. Process validation studies were performed to evaluate identity, purity, activity and safety. The manufacturing process produced rFIXFc with consistent product quality and high purity. Impurity clearance validation studies demonstrated robust and reproducible removal of process‐related impurities and adventitious viruses. The rFIXFc manufacturing process produces a highly pure product, free of non‐human glycan structures. Validation studies demonstrate that this product is produced with consistent quality and purity. In addition, the scalability and transferability of this process are key attributes to ensure consistent and continuous supply of rFIXFc.     

FAT10真核质粒的构建、转染及其蛋白的表达

目的构建类泛素基因FAT10的真核表达质粒,观察其蛋白在转染人胚肾细胞系293T中的表达。方法采用RT-PCR法扩增FAT10全长基因片段后,克隆至pMD18-T载体进行测序分析,将FAT10克隆至pcDNA5-FRT表达载体并行酶切鉴定;用脂质体LipofectamineTM2000分别介导空质粒（空载组）及重组质粒（FAT10质粒组）转染293T细胞,以脂质体混合PBS（PBS组）及未加入脂质体（未转染组）作为对照。转染48 h后,收集细胞。采用Western blot法检测293T细胞中的FAT10蛋白。结果 pMD18-FAT10重组质粒经双酶切获得498 bp片段,对PCR产物及498 bp片段进行测序,结果与GenBank报道序列完全一致。FAT10质粒组、未转染组、空载体组和PBS组FAT10蛋白表达量分别为1.556±0.072、0.334±0.051、0.425±0.095、0.382±0.063,FAT10质粒组与未转染组、空载体组和PBS组比较,P均〈0.05。结论成功构建了FAT10的真核表达质粒pcDNA5-FRT-FAT10,FAT10蛋白在293T细胞中高表达。     

The effect of arsenic trioxide on human hepatoma cell line BEL-7402 culturedin vitro

AIM To study the effect of a wide range of concentration of arsenic trioxide on human hepatoma cell lineBEL-7402 and its mechanism.METHODS The BEL-7402 cells were treated with arsenic trioxide (a final concentration of 0.5, 1 and2 μmol/L, respectively) in various durations or for 4 successive days. The cell growth and proliferation wereobserved by cell counting and cell-growth curve. Morphologic changes were studied under electronmicroscopy. Flow cytometry was used to assay cell-DNA distribution and the protein expression of Bcl-2 andBax was detected by immunocytochemical method.RESULTS The cell growth was significantly inhibited by the different concentrations of arsenic trioxide asrevealed by cell counting and cell-growth curve. Arsenic trioxide treatment at 0.5, 1 and 2 μmol/L, resultedin a sub-G1 cell peak. The decreased G0/G1 phase cell and the increased percentage of S phase cell were observed by flow cytometer, suggesting that the inhibiting effect of arsernic trioxide on BEL-7402 cell lay inG0/G1 phase cell. Apoptotis-related morphology, such as intact cell membrane, nucleic condensation,apoptotic body formation, can be seen under the electron microscopy. High protein expression level of Bcl-2and Bax was detected in 1 and 2 μmol/L arsenic trioxide-treated cells, but that of Bax was more significant.Arsenic trioxide treatment at 0.5 μmol/L resulted in higher expression level of Bcl-2 and lower expressionlevel of Bax compared with control (P1<0.01, P2<0.01).CONCLUSION Arsenic trioxide not only inhibited the proliferation but also induced apoptosis of humanhepatoma cell line BEL-7402. The induced-apoptosis effect of 1 and 2 μmol/L arsenic trioxide was relative tothe expression level of Bcl-2 and Bax.     

刚地弓形虫细胞培养上清对人结肠癌细胞sw480增殖与凋亡的影响

目的观察刚地弓形虫RH株速殖子与人结肠癌sw480细胞系共培养上清对人结肠癌sw480细胞增殖的影响和诱导其凋亡与坏死的情况。方法取对数生长期的人结肠癌sw480细胞(1×106),建立弓形虫RH株速殖子数目分别为2×106、4×106、8×106、16×106的共培养模型,观察弓形虫速殖子在sw480细胞中的寄生,提取共同孵育72h后的培养上清,以新鲜培养基稀释为半量,体外作用人结肠癌sw480细胞12h、24h、48h、72h,CKK-8法检测吸光度(A450值)并计算抑制率;Annexin-v-FITC/PI染色细胞后上流式细胞仪检测细胞凋亡与坏死率;琼脂糖凝胶电泳观察细胞凋亡DNA条带;透射电镜和荧光显微镜观察细胞形态学改变。结果弓形虫RH株速殖子可在人结肠癌sw480细胞内寄生和增殖。CKK-8法检测结果显示上述共培养上清对sw480细胞增殖抑制率随上清作用时间延长均明显增大,48h最大抑制率达44.55%。流式细胞仪检测显示实验组sw480细胞早期凋亡率和晚期凋亡与坏死率随上清作用时间延长均明显增加,48h早期凋亡率达最高值(11.54%),48h以后早期凋亡率下降,晚期凋亡和坏死率显著上升,72h总死亡率可达46.11%,细胞杀伤效果明显;琼脂糖凝胶电泳显示典型的DNA云梯状条带;荧光显微镜和透射电镜观察到细胞凋亡和坏死典型形态。结论弓形虫RH株速殖子与人结肠癌sw480细胞共培养上清对体外培养的sw480细胞增殖有明显的抑制作用,并可诱导sw480细胞凋亡与坏死。     

刚地弓形虫培养上清对乳腺癌MCF-7细胞增殖及凋亡的影响

目的观察体外培养条件下弓形虫培养上清对乳腺癌细胞MCF-7细胞增殖及其诱导其凋亡的情况。方法取对数生长期的MCF-7细胞(浓度为5×104和5×105)分别接种于不同细胞培养板,加入相同体积不同浓度弓形虫速殖子培养上清(速殖子浓度分别为2×107/mL、4×107/mL、6×107/mL、8×107/mL)与培养液共同作用12h、24h、48h、72h,四甲基氮噻唑蓝(MTT)法检测吸光度(A490值)并计算抑制率;Annexin-v-FITC/PI染色细胞后上流式细胞仪检测细胞凋亡率;AO/EB染料染色作用后细胞在荧光显微镜下观察细胞形态改变情况并拍照;琼脂糖凝胶电泳观察细胞凋亡DNA条带。结果MTT法检测结果显示MCF-7细胞增殖抑制率随着上清浓度和作用时间增加均明显增大,各实验组抑制率与对照组比较以及对照组之间比较差异均有统计学意义(P<0.05)。流式细胞仪检测显示MCF-7细胞凋亡率随着上清浓度和作用时间增加明显增大,48h达到凋亡最高值(19.79%),48h后凋亡率开始下降,死亡率增加;荧光显微镜观察实验组培养48h的MCF-7细胞,出现细胞核固缩及凋亡小体,对照组未出现凋亡小体。琼脂糖凝胶电泳见DNA梯形条带。结论弓形虫速殖子对体外培养MCF-7细胞增殖有明显的抑制作用,并可诱导MCF-7细胞凋亡。     

Docetaxel inhibits progression of human hepatoma cell line in vitro and is effective in advanced hepatocellular carcinoma

Background: Current chemotherapy for advanced hepatocellular carcinoma (HCC) is insufficient; only sorafenib has been proven to provide a modest survival benefit. A future direction of chemotherapy is to tailor treatment based on the chemosensitivity of each individual tumor. By doing so, only patients who stand to benefit from therapy will be exposed to potential side‐effects and morbidity. Although the use of docetaxel (DTX) for the treatment of lung, breast and gastric cancer has been reported, there are few reports about its use in the setting of HCC. Methods: To examine the efficacy of DTX for HCC, we established a human hepatoma cell line (TK cell) from the patient's malignant ascites from peritoneal carcinomatosis and treated it with DTX in vitro. Results: After we confirmed the efficacy of DTX in vitro, we treated our patient with DTX with positive results. Conclusion: In this study, we present a therapeutic approach by using DTX that supports the potential usefulness of personalized medicine in vitro and demonstrates it clinically.     

人食管癌Eca-109细胞膜蛋白分离纯化方法的研究

目的　建立人食管癌细胞株Eca 10 9细胞膜蛋白分离和初步纯化方法。方法　使用改良的Neville法提取细胞膜 ,在pH 6.3的条件下 ,用去垢剂TritonX 10 0和辛基 β 葡糖苷把细胞膜上的蛋白溶解下来 ,以超滤法纯化膜蛋白并分组。 结果　在pH6.3的条件下 ,适当的去垢剂与膜蛋白之比 (即mg去垢剂 /mg膜蛋白 ) ,使用辛基 β 葡糖苷时为 6∶1;使用TritonX 10 0时为 2∶1。超滤法将膜蛋白分为 <3KD、3～ 10KD、<10KD、10～ 3 0KD、3 0～ 10 0KD、>10 0KD共 6个组。结论　为进一步研究食管癌Eca 10 9细胞肿瘤抗原奠定基础     

蚌皮素对结肠癌细胞株调控及其受体后信息传导

研究蛙皮素对人结肠癌细胞株的生长调控及受体后的信息传导途径。方法观察蛙皮素对人结肠癌细胞株ｃｌｏｎｅ Ａ细胞生长调控;应用液体闪烁测量法【闪烁记数仪分别测定细胞内三磷酸肌醇及环磷酸腺苷含量;用荧光测定细胞内游离Ｃａ＾２＋浓度;参考Ｔａｋａｉ法测定蛋白激酶Ｃ活性。     

人食管癌顺铂耐药细胞系Ec9706/cDDP的建立及其生物学特征

目的:建立人食管癌顺铂耐药细胞系Ec9706/cDDP,探讨其生物学特征.方法:采用顺铂(cDDP)中等浓度、间歇作用方法历时9mo建立耐药细胞系Ec9706/cDDP,采用MTT法测定其对cDDP的耐药指数,观察冻存、撤药对耐药性的影响,比较耐药与亲本细胞生长曲线、群体倍增时间及贴壁率的不同,流式细胞仪测细胞周期,软琼脂实验测细胞的恶性增殖能力,罗丹明实验测其对药物的摄入、排出能力.结果:人食管癌顺铂耐药细胞系Ec9706/cDDP的耐药指数为15.7,冻存对耐药性影响不大,撤药培养可使耐药性降低,耐药细胞群体倍增时间延长(29.79±0.48hvs25.79±0.45h,P<0.05),生长缓慢,G0/G1、S期细胞比例增加(63.18%±5.21%vs52.81%±4.36%,P<0.05;36.49%±3.93%vs26.70%±2.62%,P<0.05),G2期细胞减少(0.33%±0.02%vs20.49%±3.71%,P<0.05),克隆形成率明显高于亲本细胞(69%vs24%,P<0.05),对罗丹明的摄入减少,排出增多.结论:成功建立了人食管癌顺铂耐药细胞系Ec9706/cDDP,且耐药性较稳定.     

Tandem high-dose therapy (HDT) for multiple myeloma: recombinant human erythropoietin therapy given between first and second HDT allows second peripheral blood stem cell transplantation without red blood cell transfusion

We evaluated the ability of recombinant human erythropoietin (rHuEpo) therapy, given before high-dose therapy (HDT), to allow autologous peripheral blood stem cell transplantation (PBSCT) without red blood cell (RBC) transfusions. Eleven multiple myeloma patients underwent tandem HDT and autologous PBSC, receiving 500 U/kg/week rHuEpo from d 30 after initial transplant. Haemoglobin levels were 9.5 +/- 1.1 g/dl and 12.5 +/- 0.9 g/dl at the first and second transplant respectively (P < 0.001). RBC transfusions were required for 10/11 patients for the first transplant versus 1/11 for the second (P < 0.001). To conclude, a short course of rHuEpo therapy before HDT facilitates the performance of an autologous transplant without RBC transfusions.     

Bb1-3, a transgenic hybrid cell line with erythroid and megakaryocytic differentiation potential that expresses high levels of human γ-globin and human β-globin

We have characterized a murine hybrid cell line, Bb1-3, generated by the fusion of mouse primary erythroblasts with MEL cells. It proliferated in serum-free medium and displayed a low level of spontaneous erythroid and megakaryocyte differentiation. Terminal erythroid differentiation could be induced with HMBA and DMSO and was enhanced by serum. Treatment with phorbol esters resulted in a high proportion of megakaryocytes and the expression of megakaryocytic specific lineage markers. Bb1-3 cells contain a human β-globin transgene that was expressed at levels of 20–50% of the endogenous mouse globin genes. Initially, expression was largely limited to the β-globin gene but after adaptation to serum free growth, equal expression of both the human γ- and human β-globin genes was observed. This cell line provides further evidence that the differentiation potential of mouse erythroleukaemia cells is not restricted to the erythroid lineage and should be useful to study the mechanisms underlying both developmental globin gene regulation and the terminal differentiation of bipotential erythroid/megakaryocytic progenitor cells.