A Phase II trial of topical sodium nitrite in patients with sickle cell disease and leg ulcers

摘要 腿部溃疡长期以来一直被认为是镰状细胞病的一种严重和使人衰弱的并发症 1910年在北美描述的第一个SCD患者具有腿部溃疡。患病率不同， 10岁以前和SS以外的基因型中低。受地理位置的影响， 在牙买加SS患者中的发生率高达75%，在北美为8 - 10%。慢性病的病因 SCD和其他溶血性疾病中的溃疡是未知的-致密镰状红细胞的机械性阻塞， 静脉压升高、细菌感染、自主神经控制异常伴过度血管收缩 当处于依赖位置时，贫血程度与携氧能力下降，均已被 作为潜在的影响因素。 尽管取得了进展，但慢性腿部溃疡的发病率仍然是SCD患者的重大临床负担 与疾病调节剂如羟基脲、输血和改善的支持性护理一起护理。 镰状细胞病和腿部溃疡的患者有更严重的溶血性贫血的生物标志物， 与一氧化氮的低生物利用度有关。SCD溃疡的现有治疗方法是 目前的治疗方法并不令人满意，并且大多基于一般人群中静脉和动脉溃疡的治疗。一 最近的一项科克伦综述仅确定了6项针对镰状细胞病下肢的前瞻性随机治疗试验 在过去的30年中，牙买加有4例，美国有2例。结果混合;统计学显著 仅局部Arg-Gly-Asp（RGD）肽和静脉注射精氨酸 丁酸盐。由于这些药物仍处于早期药物开发阶段，患者的治疗选择很少 available.我们选择亚硝酸钠的临床开发的基础上，广泛发表的文献 关于其静脉和口服给药时的安全性，其血管舒张特性，以及初步的 报道了酸化亚硝酸盐在治疗患有慢性皮肤溃疡的其他患者群体中的功效。 在动物中，亚硝酸钠治疗促进缺血肢体的血管重建， 心脏，肝脏和大脑的梗塞，并对心脏骤停介导的心脏和 脑损伤亚硝酸根阴离子通过在低氧组织中产生一氧化氮而在体内起血管扩张剂的作用 张力和pH值，可能存在于慢性伤口中的条件。它的机制包括氧气- 血红素蛋白或黄嘌呤氧化还原酶的依赖性和pH依赖性亚硝酸盐还原酶活性。 实验模型表明，一氧化氮在伤口愈合的早期和晚期具有有益作用， 包括增加细胞外基质产生、免疫应答调节和刺激细胞外基质， 角质形成细胞增殖、血管生成和杀菌特性。一氧化氮介导必需的 血管稳态，包括血管舒张和抗血小板活性，并影响几种生长因子 参与内皮细胞的稳态。 我们已经在18名镰状细胞贫血成年患者中完成了一项剂量递增、安全性和耐受性的I期研究。 贫血和腿部溃疡未发生3 - 4级不良事件、严重不良事件或剂量限制性副作用- 方面的影响.药代动力学分析显示亚硝酸钠的全身吸收较低。施加局部 亚硝酸钠与伤口周围皮肤血流量的显著增加相关， 激光散斑对比度成像和通过红外热成像法增加的伤口周围皮肤温度。 有趣的是，腿部溃疡大小（p = 0.0012）和溃疡相关疼痛呈剂量依赖性降低 （p <0.0001）。三名接受最高浓度局部药物治疗的患者溃疡完全愈合， 亚硝酸钠（1.8%和2%奶油）。疼痛的事后分析显示疼痛严重程度降低 （p = 0.0048）和疼痛干扰（p = 0.0013）。 在这些令人鼓舞的结果的基础上，我们提出了一个前瞻性，双盲，随机II期试验 其目的是： 1.进一步评估每周两次长期（10周）给药的安全性和耐受性 亚硝酸钠局部应用于成人镰状细胞病和下肢 在一项随机、双盲、安慰剂对照的II期临床试验中， 2.确定局部亚硝酸钠在加速伤口愈合方面的有效性， 与安慰剂相比，在接受类似治疗的患者中， 伤口护理水平。 3.提高我们对腿部溃疡形成的病理生物学的理解， 治疗SCD患者。

Abstract Leg ulcerations have long been identified as a serious and debilitating complication of sickle cell disease (SCD).The first SCD patient described in North America in 1910 had leg ulcerations. Prevalence varies, being low before 10 years of age and in genotypes other than SS. It is influenced by geographical location, with occurrence as high as 75% in SS patients in Jamaica, and 8-10% in North America. The etiology of chronic ulcers in SCD and other hemolytic disorders is unknown - mechanical obstruction by dense sickled red cells, increased venous pressure, bacterial infections, abnormal autonomic control with excessive vasoconstriction when in dependent position, degree of anemia with decrease in oxygen carrying capacity, have all been proposed as potential contributing factors. Morbidity from chronic leg ulcers remains a substantial clinical burden in patients with SCD despite advances in care with disease-modifying agents such as hydroxyurea, blood transfusions, and improved supportive care. Patients with sickle cell disease and leg ulcers have biomarkers of more severe hemolytic anemia, a state associated with low bioavailability of nitric oxide. Existing therapeutic approaches for SCD ulcers are unsatisfactory, and are mostly based on treatments for venous and arterial ulcers in the general population. A recent Cochrane review identified only six prospective, randomized therapeutic trials for sickle cell disease leg ulcers over the past 30 years—four in Jamaica and two in the USA. Results were mixed; statistically significant increases in wound closure were reported only for topical Arg-Gly-Asp (RGD) peptide and intravenous arginine butyrate. As these agents remain in early-phase drug development, patients have few therapeutic options available. We selected sodium nitrite for clinical development on the basis of the extensive published literature about its safety profile when administered intravenously and orally, its vasodilating properties, and preliminary reports of the efficacy of acidified nitrite in the treatment of other patient populations with chronic skin ulcers. In animals, sodium nitrite therapy promotes revascularization of ischemic limbs, protects against ischemic infarction of the heart, liver, and brain, and has a protective effect against cardiac arrest-mediated heart and brain injury. The nitrite anion acts as a vasodilator in vivo by generating nitric oxide in tissues with low oxygen tension and pH, conditions which are likely to be present in chronic wounds. The mechanism involves oxygen- dependent and pH-dependent nitrite reductase activity of hemoproteins or xanthine oxidoreductase. Experimental models suggest beneficial effects of nitric oxide in the early and late phases of wound healing, including increased extracellular matrix production, immune response modulation, and stimulation of keratinocyte cell proliferation, angiogenesis, and bactericidal properties. Nitric oxide mediates essential vascular homoeostasis, including vasodilation, and antiplatelet activity, and affects several growth factors involved in endothelial homoeostasis. We have completed a dose escalation, safety and tolerability phase 1 study in 18 adult patients with sickle cell anemia and leg ulcers. There were no grade 3–4 adverse events serious adverse events or dose-limiting side- effects. Pharmacokinetic analysis showed low systemic absorption of sodium nitrite. Application of topical sodium nitrite was associated with a significant increase in peri-wound cutaneous blood flow measured by laser speckle contrast imaging and increased peri-wound skin temperature by infrared thermography. Interestingly, there was a dose-dependent decrease in leg ulcer size (p=0.0012) and ulcer associated pain (p<0.0001). Ulcers healed completely in three patients who received the highest concentrations of topical sodium nitrite (the 1.8% and 2% cream). Post-hoc analysis of pain revealed decreased pain severity (p=0.0048) and pain interference (p=0.0013). On the basis of these encouraging results we propose a prospective, double blinded, randomized Phase II trial which aims at: 1. Further evaluate the safety and tolerability of prolonged (10 weeks), twice a week application of topical sodium nitrite in adult patients with sickle cell disease and leg ulcers in a randomized, double blind, placebo controlled Phase II trial. 2. Determine the effectiveness of topical sodium nitrite in accelerating wound healing and decrease pain at the wound site compared to placebo in patients receiving similar levels of wound care. 3. Improve our understanding of the pathobiology of leg ulcer formation and delayed healing in patients with SCD.