Developing a paper-based diagnostic test for sickle cell disease

项目总结/摘要 全球75%以上的镰状细胞病（SCD）负担由低收入发展中国家承担。 撒哈拉以南非洲国家，出生时SCD的发病率可高达4.2%，镰刀型为23.7% 特质SCD对幼儿尤其致命，占各国5岁以下儿童死亡率的15 患病率最高的国家非洲试点项目的数据表明， 可以通过廉价的治疗（如青霉素预防、肺炎球菌预防）来预防死亡。 免疫接种、疟疾蚊帐和关于发烧就医重要性的教育）- 只要SCD能在生命早期被诊断出来在我们的第一阶段工作中，我们成功地开发了一种简单的 和廉价的纸基测试用于诊断>6个月大的婴幼儿的SCD。我们 该测试能够通过对色谱纸上产生的染色图案的视觉解释进行诊断， 与血红蛋白（Hb）溶解度缓冲液混合的血液液滴。当前版本的纸本SCD测试 试剂盒是完全设备和电力免费，只需要10微升的血液样本，成本<0.15美元每测试，可以 在35分钟内完成，不受严重贫血、高HbF、环境温度升高或 湿度它具有<20%HbS的检测极限，并且能够检测任何HbS（镰状细胞）的存在。 特征或疾病），在资源的临床前研究中具有94%的灵敏度和97%的特异性， 有限环境（n = 226，卡宾达，安哥拉）。在我们的实验室中，该测试能够诊断SCD，93% 敏感性和94%特异性（n = 55）。在第二阶段，我们建议发展一套完整、独立的 诊断试剂盒，并证明其诊断准确性的关键临床试验在多个地点， 撒哈拉以南非洲的几个国家。我们将首先评估使用原型套件的可行性， 在省级医院就诊的急性疾病儿童目标患者人群中诊断SCD 德卡宾达。我们还将收集有关测试组件和说明的设计和可用性的输入， 研究中心工作人员，以告知成品、可销售的诊断试剂盒的平行开发。然后我们将工作 与我们的合同制造合作伙伴一起开发针对大规模优化的诊断试剂盒版本 生产、监管试验和随后的营销。这一迭代过程将不断得到以下信息： 我们实验室的研究和开发，来自卡宾达网站的可用性数据，以及我们 营销和分销合作伙伴。最后，我们将展示成品的诊断准确性， 在撒哈拉以南非洲的一项关键临床试验中，目前，我们已经确定了5个- 合格的临床研究中心-莫罗戈罗（坦桑尼亚）、巴马科（马里）、卢萨卡（赞比亚）、伊巴丹（尼日利亚）和卡宾达 （安哥拉）--每一个都对参与我们的试验非常感兴趣。我们将与指导委员会密切合作， 和FDA来完成试验的设计。

PROJECT SUMMARY / ABSTRACT More than 75% of the global burden of sickle cell disease (SCD) is carried by the low-income developing countries of sub-Saharan Africa, where incidence at birth can be as high as 4.2% for SCD and 23.7% for sickle trait. SCD is particularly lethal to young children, accounting for up to 15% of under-5 mortality in countries with the highest prevalence of the disease. Data from pilot programs in Africa demonstrate that most of these deaths can be prevented with inexpensive treatments (e.g. penicillin prophylaxis, pneumococcal immunizations, malaria bed nets, and education about the importance of seeking medical attention for fever) – provided SCD could be diagnosed early in life. In our Phase I work, we have successfully developed a simple and inexpensive paper-based test for the diagnosis of SCD in infants and young children >6 months old. Our test enables the diagnosis via visual interpretation of the stain pattern produced on chromatography paper by a droplet of blood mixed with hemoglobin (Hb) solubility buffer. The current version of the paper-based SCD test kit is completely equipment- and electricity-free, requires only a 10µL blood sample, costs <$0.15 per test, can be completed in 35 min, and is unaffected by severe anemia, high HbF, elevated ambient temperature or humidity. It has a limit of detection of <20% HbS, and was able to detect the presence of any HbS (sickle cell trait or disease) in patient samples with 94% sensitivity and 97% specificity in a pre-clinical study in a resource- limited setting (n = 226, Cabinda, Angola). In our laboratory, the test was able to diagnose SCD with 93% sensitivity and 94% specificity (n = 55). In Phase II, we propose to develop a complete, self-contained diagnostic kit, and to demonstrate its diagnostic accuracy in a pivotal clinical trial across multiple sites in several countries in sub-Saharan Africa. We will first evaluate the feasibility of using a prototype kit for diagnosing SCD in the target patient population of children presenting with acute illness to Hospital Provincial de Cabinda. We will also collect input on design and usability of the test’s components and instructions from the site personnel, to inform parallel development of the finished, marketable diagnostic kit. We will then work with our contract manufacturing partners to develop a version of the diagnostic kit that is optimized for mass production, regulatory trials, and subsequent marketing. This iterative process will be continually informed by research and development in our laboratory, the usability data from the Cabinda site, and advice from our marketing and distribution partners. Finally, we will demonstrate the diagnostic accuracy of the finished, marketable SCD test kit in a pivotal clinical trial in sub-Saharan Africa. We have, to date, identified 5 well- qualified clinical sites – Morogoro (Tanzania), Bamako (Mali), Lusaka (Zambia), Ibadan (Nigeria), and Cabinda (Angola) – each highly-interested in participating in our trial. We will work closely with our Steering Committee and the FDA to finalize the design of the proposed trial.