枸橼酸铁片Zerenex(ferric citrate coordination complex)治疗慢性肾病患者高磷酸盐血症的新药
2013年11月6日，Keryx生物制药公司最近披露其治疗慢性肾脏疾病（CKD）药物Zerenex疗效显着，这一结果也助涨公司股价。Zerenex是被设计治疗高磷酸盐血症的药物，高磷酸盐血症主要常见于一些CKD患者，血液中磷酸盐浓度过高会导致生命危险。而此次而其研究Zerenex对缺铁性贫血也有很好疗效，预示着Zerenex未来可能有更广阔的应用。在此次有149名CKD患者参与的研究中，研究人员发现Zerenex有效降低了患者血液中磷酸盐的含量并提高了铁离子含量。一旦Zerenex同时获得了治疗缺铁性贫血的认证，这种药物将可能增加150万潜在患者用户。
然而，Zerenex的前景并不是像看上去那么美好，因为其主要成分和日本大冢公司的Ferriseltz相近，FDA可能不会批准其创新药物地位，这也意味着Zerenex可能很快会面临仿制药的挑战。
Keryx Biopharmaceuticals' Zerenex Likely To Receive FDA Approval
Keryx Biopharmaceuticals (KERX) has a pending new drug application (NDA) filing for Zerenex, which treats hyperphosphatemia in patients on dialysis with end stage renal disease (ESRD). The company has indicated that it will submit its NDA to the United States Food and Drug Administration (FDA) by August of this year. Based on publicly available scientific literature and clinical data, we believe that the FDA will accept this NDA and then ultimately approve Zerenex. As outlined below, we also believe that these events will have a substantial positive impact on Keryx's stock price.
Background
Keryx Biopharmaceuticals focuses on the acquisition, development, and commercialization of pharmaceuticals for the treatment of renal diseases. In 2010, Keryx licensed Zerenex from Taiwan-based Panion & BF Biotech. Zerenex has been developed for the treatment of hyperphosphatemia in ESRD patients on dialysis. Hyperphosphatemia, characterized by an increase in the level of phosphate in the blood, can lead to brittle bones and cause damage to the cardiovascular system. Hyperphosphatemia occurs universally in ESRD patients. These patients often require phosphate-binding agents to lower and maintain serum phosphorus at an acceptable level. In the United States, there are approximately 600,000 patients with ESRD, more than 400,000 of whom require dialysis. Worldwide, there are approximately three million patients with ESRD, with the majority of them--over two million--requiring dialysis.
Phosphate is a common additive in processed food and soda drinks. Consequently, it is difficult to control phosphate intake through diet alone. Typically, hyperphosphatemia is treated through oral administration of phosphate binders that sequester excess phosphate derived from ingested food. Relevant phosphate-binding drugs include Renagel by Genzyme/Sanofi (SNY), Fosrenol by Shire Pharmaceuticals (SHPG), and over-the-counter drugs, such as Oyster Cal and Calphron. These drugs function by reacting with phosphate anions to form insoluble precipitates that the body then secretes, thereby lowering the amount of phosphate in the blood. However, these drugs also have quite meaningful limitations. Calcium or aluminum found in phosphate binders can accumulate and cause ectopic tissue calcification. Furthermore, although Fosrenol tablets are supposed to be chewed, they present a choking hazard because patients sometimes attempt to swallow the tablets without chewing them first. In contrast to existing therapies, Zerenex is an iron-based phosphate binder. Its effective component is ferric citrate, which binds to phosphate and forms non-absorbable complexes that do not result in calcium accumulation. Additionally, Zerenex is produced as a relatively small pill that does not require chewing, thus avoiding the risk of choking. |
