——Sensipar治疗甲状旁腺癌引起的高钙血症 生物技术公司安进2004年7月30日宣布，该公司生产的新药Mimpara获得欧盟人用药品委员会推荐。 该药于今年3月获FDA批准，通用名为cinacalcetHCI,在美国以商品名Sensipar上市。                                           Cinacalcet是第一种被FDA批准的此类药物。PTH水平升高是甲状旁腺功能亢进的标志，改变钙磷代谢，使骨质疏松，并且是冠心病的诱发因素。Cinacalcet可以降低血清PTH水平，从而调节钙磷代谢。Cinacalcet还可以治疗甲状旁腺癌引起的高钙血症。血液中钙含量过多可以引起明显的精神混乱、嗜睡、脱水、恶心呕吐、便秘和肾损伤。 cinacalcet                                       HCl是新分子实体(NME)。Sensipar是一种具有独特作用机理的口服化合物。它调节甲状旁腺钙受体的行为，通过增强受体对血流中钙水平的敏感性，它降低甲状旁腺激素、钙、磷和钙-磷产品的水平。目前，还没有具有这些特性的治疗药出现。它获准的适应症为，用于治疗慢性肾病(CKD)行透析病人的继发性甲状旁腺功能亢进(继发性HPT)和用于治疗甲状旁腺癌患者的钙水平升高(高钙血)。对于两者Sensipar都是一个明显的医疗进步。这是Amgen公司(它是NPS制药公司这个产品的许可权受让人)的第一个小分子治疗药，同时也是自1990年代初发现calcimimetic化合物以来第一个这类使肾和甲状旁腺病患者得益的药物。                                           经过6个月1000多个接受血透治疗的慢性肾衰患者临床试验证明，本药最主要的副作用为恶心呕吐。使用本药的患者恶心发生率31％，呕吐发生率27％，而使用安慰剂的患者其发生率分别为19%和15%。使用本药对肾衰患者的高钙血症也有明显作用。 商品名：Ｓｅｎｓｉｐａｒ（安进公司） 盐酸西那卡塞（Ｃｉｎａｃａｌｃｅｔ Ｈｙｄｒｏｃｈｌｏｒｉｄｅ）是一种拟钙剂，当它与维生素Ｄ类似物和磷酸盐结合剂合用时，可降低体内甲状旁腺素（ＰＴＨ）和血清钙水平。该药于２００４年３月８日获得美国食品药品管理局（ＦＤＡ）批准。                                     【适应症】该药主要用于治疗肾病透析患者的继发性甲状旁腺机能亢进，或者甲状旁腺癌所致的高钙血症。                                     【药理及药代动力学】该药可与甲状旁腺中的钙敏感受体结合，减少甲状旁腺素的分泌，进而导致血清钙及磷酸钙产物水平的降低。通常而言，原发性甲状旁腺功能亢进患者会在服用该药第二剂后２小时内 观察到最初的治疗反应；在治疗开始后４～６周内观察到持续的治疗反应                                     该药达峰时间为２～６小时。该药与高脂饮食同服时，可导致血药浓度和药时曲线下面积（ＡＵＣ）升高。该药蛋白结合率为９３％～９７％，分布容积达１０００升。细胞色素Ｐ４５０ ３Ａ４、２Ｄ６和１Ａ２均与该药代谢有关。代谢产物主要通过尿液（８０％）和粪便（１５％）排泄，消除半衰期为４０小时。 【注意事项】                                     该药可降低血清钙水平，因而可能引起低钙血症。患者应注意观察是否有感觉异常、肌痛、痉挛、手足抽搐和惊厥的发生。 【药物相互作用】该药是细胞色素Ｐ４５０２Ｄ６（ＣＹＰ２Ｄ６）同功酶的抑制剂，因此，当该药与同样通过ＣＹＰ２Ｄ６代谢，且治疗指数较小的药物（如氟卡胺、长春碱、硫利达嗪和大多数三环类抗抑郁药）合用时，后者可能需要调整给药剂量。开始应用或停用ＣＹＰ３Ａ４强抑制剂（如酮康唑、红霉素或伊曲康唑）时，均有可能导致同时应用的该药的血药浓度发生较大幅度改变，因而需相应调整该药剂量。                                     【不良反应】临床试验中该药最常见的不良事件为恶心和呕吐。其他发生率大于５％的不良事件还包括腹泻、肌痛、高血压、无力、食欲减退、非心脏性胸痛和通路感染（ａｃｃｅｓｓｉｎｆｅｃｔｉｏｎ）。此外，西那卡塞治疗组和安慰剂对照组的严重感染发生率基本相当。 【剂量及用药】该药为口服片剂，规格为３０ｍｇ／片。该药应整片吞服，初始剂量为３０ｍｇ／天，进食时服用。随后根据患者反应情况，每２～４周调整一次剂量（按６０ｍｇ／天、９０ｍｇ／天、１２０ｍｇ／天和１８０ｍｇ／天顺序依次递增），直至患者ＰＴＨ水平达到美国肾脏基金会临床指南推荐的标准（１５０～３００ｐｇ／ｍｌ）。该药可单独应用或与维生素Ｄ醇和磷酸盐结合剂合用。 【患者咨询】 服用该药期间，患者应避免怀孕或哺乳。许多药物可能与该药产生药物相互作用，因此服用该药时应尽量停用其他药物，包括非处方药和营养补充剂。提醒患者在出现下述不良反应时，应尽快与医师联系，并采取相应治疗措施。这些不良反应包括：腹部痉挛或疼痛；面部、口唇、舌头和手足出现烧灼感、麻痹、刺痛、瘙痒或麻刺感；背部或腿部出现痛性痉挛；抑郁；意识错乱；吞咽或呼吸困难；幻觉；易怒；面肌抽搐；肌痛或癫痫发作。  Sensipar Generic Name: cinacalcet Dosage Form: tablets  Description Sensipar® (cinacalcet) is a calcimimetic agent that increases the sensitivity of the calcium-sensing receptor to activation by extracellular calcium. Its empirical formula is C22H22F3N•HCl with a molecular weight of 393.9 g/mol (hydrochloride salt) and 357.4 g/mol (free base). It has one chiral center having an R-absolute configuration. The R-enantiomer is the more potent enantiomer and has been shown to be responsible for pharmacodynamic activity. Cinacalcet is a white to off-white, crystalline solid that is soluble in methanol or 95% ethanol and slightly soluble in water. Sensipar® tablets are formulated as light-green, film-coated, oval-shaped tablets for oral administration in strengths of 30 mg, 60 mg, and 90 mg of cinacalcet as the free base equivalent (33 mg, 66 mg, and 99 mg as the hydrochloride salt, respectively). Cinacalcet is described chemically as N-[1-(R)-(-)-(1-naphthyl)ethyl]-3-[3-(trifluoromethyl)phenyl]-1-aminopropane hydrochloride and has the following structural formula: Inactive Ingredients: Sensipar® tablets are comprised of the active ingredient, and the following inactive ingredients: pre-gelatinized starch, microcrystalline cellulose, povidone, crospovidone, colloidal silicon dioxide, and magnesium stearate. Tablets are coated with color (Opadry® II green) and clear film-coat (Opadry® clear), carnauba wax, and Opacode® black ink.  Sensipar - Clinical Pharmacology Mechanism of Action Secondary hyperparathyroidism (HPT) in patients with chronic kidney disease (CKD) is a progressive disease, associated with increases in parathyroid hormone (PTH) levels and derangements in calcium and phosphorus metabolism. Increased PTH stimulates osteoclastic activity resulting in cortical bone resorption and marrow fibrosis. The goals of treatment of secondary hyperparathyroidism are to lower levels of PTH, calcium, and phosphorus in the blood, in order to prevent progressive bone disease and the systemic consequences of disordered mineral metabolism. In CKD patients on dialysis with uncontrolled secondary HPT, reductions in PTH are associated with a favorable impact on bone-specific alkaline phosphatase (BALP), bone turnover and bone fibrosis. The calcium-sensing receptor on the surface of the chief cell of the parathyroid gland is the principal regulator of PTH secretion. Sensipar® directly lowers PTH levels by increasing the sensitivity of the calcium-sensing receptor to extracellular calcium. The reduction in PTH is associated with a concomitant decrease in serum calcium levels. Pharmacokinetics Absorption and Distribution After oral administration of cinacalcet, maximum plasma concentration (Cmax) is achieved in approximately 2 to 6 hours. A food-effect study in healthy volunteers indicated that the Cmax and area under the curve (AUC(0-inf)) were increased 82% and 68%, respectively, when cinacalcet was administered with a high-fat meal compared to fasting. Cmax and AUC(0-inf) of cinacalcet were increased 65% and 50%, respectively, when cinacalcet was administered with a low-fat meal compared to fasting. After absorption, cinacalcet concentrations decline in a biphasic fashion with a terminal half-life of 30 to 40 hours. Steady-state drug levels are achieved within 7 days. The mean accumulation ratio is approximately 2 with once-daily oral administration. The median accumulation ratio is approximately 2 to 5 with twice-daily oral administration. The AUC and Cmax of cinacalcet increase proportionally over the dose range of 30 to 180 mg once daily. The pharmacokinetic profile of cinacalcet does not change over time with once-daily dosing of 30 to 180 mg. The volume of distribution is high (approximately 1000 L), indicating extensive distribution. Cinacalcet is approximately 93 to 97% bound to plasma protein(s). The ratio of blood cinacalcet concentration to plasma cinacalcet concentration is 0.80 at a blood cinacalcet concentration of 10 ng/mL. Metabolism and Excretion Cinacalcet is metabolized by multiple enzymes, primarily CYP3A4, CYP2D6 and CYP1A2. After administration of a 75 mg radiolabeled dose to healthy volunteers, cinacalcet was rapidly and extensively metabolized via: 1) oxidative N-dealkylation to hydrocinnamic acid and hydroxy-hydrocinnamic acid, which are further metabolized via β-oxidation and glycine conjugation; the oxidative N-dealkylation process also generates metabolites that contain the naphthalene ring; and 2) oxidation of the naphthalene ring on the parent drug to form dihydrodiols, which are further conjugated with glucuronic acid. The plasma concentrations of the major circulating metabolites including the cinnamic acid derivatives and glucuronidated dihydrodiols markedly exceed parent drug concentrations. The hydrocinnamic acid metabolite was shown to be inactive at concentrations up to 10 µM in a cell-based assay measuring calcium-receptor activation. The glucuronide conjugates formed after cinacalcet oxidation were shown to have a potency approximately 0.003 times that of cinacalcet in a cell-based assay measuring a calcimimetic response. Renal excretion of metabolites was the primary route of elimination of radioactivity. Approximately 80% of the dose was recovered in the urine and 15% in the feces. Special Populations Hepatic Insufficiency The disposition of a 50 mg cinacalcet single dose was compared in patients with hepatic impairment and subjects with normal hepatic function. Cinacalcet exposure, AUC(0-inf), was comparable between healthy volunteers and patients with mild hepatic impairment. However, in patients with moderate and severe hepatic impairment (as indicated by the Child-Pugh method), cinacalcet exposures as defined by the AUC(0-inf) were 2.4 and 4.2 times higher, respectively, than that in normals. The mean half-life of cinacalcet is prolonged by 33% and 70% in patients with moderate and severe hepatic impairment, respectively. Protein binding of cinacalcet is not affected by impaired hepatic function. See PRECAUTIONS and DOSAGE AND ADMINISTRATION. Renal Insufficiency The pharmacokinetic profile of a 75 mg Sensipar® single dose in patients with mild, moderate, and severe renal insufficiency, and those on hemodialysis or peritoneal dialysis is comparable to that in healthy volunteers. Geriatric Patients The pharmacokinetic profile of Sensipar® in geriatric patients (age ≥ 65, n = 12) is similar to that for patients who are < 65 years of age (n = 268). Pediatric Patients The pharmacokinetics of Sensipar® have not been studied in patients < 18 years of age. Drug Interactions An in vitro study indicates that cinacalcet is a strong inhibitor of CYP2D6, but not of CYP1A2, CYP2C9, CYP2C19, and CYP3A4. In vitro induction studies indicate that cinacalcet is not an inducer of CYP450 enzymes. Ketoconazole: Cinacalcet AUC(0-inf) and Cmax increased 2.3 and 2.2 times, respectively, when a single 90 mg cinacalcet dose on Day 5 was administered to subjects treated with 200 mg ketoconazole twice daily for 7 days compared to 90 mg cinacalcet given alone (see DOSAGE AND ADMINISTRATION). Calcium Carbonate: No significant pharmacokinetic interaction was observed when a single dose of 1500 mg calcium carbonate was coadministered with 100 mg cinacalcet. Pantoprazole: No significant pharmacokinetic interaction was observed when cinacalcet 90 mg was administered to subjects treated with 80 mg pantoprazole daily for 3 days. Sevelamer HCl: No significant pharmacokinetic interaction was observed when 2400 mg sevelamer HCl was coadministered with 90 mg cinacalcet tablet (subjects subsequently received 2400 mg sevelamer HCl two more times on Day 1 and three more times on Day 2). Desipramine: The effect of cinacalcet (90 mg) on the pharmacokinetics of desipramine (50 mg) has been studied in healthy subjects who were CYP2D6 extensive metabolizers. The AUC and Cmax of desipramine increased by 3.6 (296.5-446.7%) and 1.75 (157.5-194.9%) fold, respectively, in the presence of cinacalcet. This indicates that cinacalcet is a strong in vivo inhibitor of CYP2D6 and can increase the blood concentrations of drugs metabolized by CYP2D6. Amitriptyline: Concurrent administration of 25 mg or 100 mg cinacalcet with 50 mg amitriptyline increased amitriptyline exposure and nortriptyline (active metabolite) exposure by approximately 20% in CYP2D6 extensive metabolizers. Warfarin: R- and S-warfarin pharmacokinetics and warfarin pharmacodynamics were not affected in subjects treated with warfarin 25 mg who received cinacalcet 30 mg twice daily. The lack of effect of cinacalcet on the pharmacokinetics of R- and S-warfarin and the absence of auto-induction upon multiple dosing in patients indicates that cinacalcet is not an inducer of CYP2C9 in humans. Midazolam: There were no significant differences in the pharmacokinetics of midazolam, a CYP3A4 and CYP3A5 substrate, in subjects receiving 90 mg cinacalcet once daily for 5 days and a single dose of 2 mg midazolam on day 5 as compared to those of subjects receiving 2 mg midazolam alone.  This suggests that cinacalcet would not affect the pharmacokinetics of drugs predominantly metabolized by CYP3A4 and CYP3A5. Pharmacodynamics Reduction in intact PTH (iPTH) levels correlated with cinacalcet concentrations in CKD patients. The nadir in iPTH level occurs approximately 2 to 6 hours post dose, corresponding with the Cmax of cinacalcet. After steady state is reached, serum calcium concentrations remain constant over the dosing interval in CKD patients.