部分中文MYOZYME信息资料（仅供参考）

FDA当天批准了Myozyme（通用名：alglucosidase alfa, rhGAA）的生物制品许可申请(biologics license application，BLA)，Myozyme是首个治疗庞培氏病（Pompe）的药物。庞培氏病是一种罕见但严重的衰竭性疾病（debilitating disease），急剧降低了人的肌肉及呼吸功能，该病在每4万到30万人中影响1人。Myozyme已被批准为FDA指定罕见病药，并被批准优先审查。罕见病产品的开发，用于治疗在美国影响少于20万人的罕见疾病或症状，《罕见病药品法》（Orphan Drug Act）给获得一个指定罕见病药上市批准的首个申请者提供了7年的市场独占期。
“该批准是罕见病药计划益处的又一个例子，激励了用于治疗在美国影响少于20万患者的疾病的药物开发，”FDA的药物评价与研究中心主任Steven Galson博士称，“直到现在，庞培氏病尚无已获批准的药物。”
庞培氏病是一种酸性α-葡萄糖苷酶（enzyme acid alpha-glucosidase）缺乏或缺失引起的遗传疾病，这种酶是正常的肌肉生长及肌肉功能所必需的。该病通常导致呼吸衰竭死亡，在新生婴儿中迅速致命。
FDA批准Myozyme通过静脉输液给药。在两项独立临床试验中，对39位1个月至3.5岁的患有庞培氏病的婴幼儿的首次给药评估了Myozyme的安全性及有效性。
使用该药治疗的婴幼儿患者与未使用该药的同龄同病况患者的已知高致命性相比，无需侵入型吸氧（invasive ventilatory）维持生命的存活率比预计的明显增高。该药在其他形式庞培氏病中的安全性和有效性，尚未得到充分研究。
对Myozyme最严重的不良反应报道是心脏与肺衰竭及过敏性休克。最常见的反应包括肺炎、呼吸衰竭与呼吸困难、感染及发烧。Myozyme标签中包含的一个加框警告称可能存在威胁生命的过敏反应。

Myozyme由美国马塞诸塞州剑桥市的Genzyme公司生产。

Myozyme ® (alglucosidase alfa) is a lysosomal glycogen-specific enzyme indicated for use in patients with Pompe disease (GAA deficiency).

MYOZYME (alglucosidase alfa) is a lysosomal glycogen-specific enzyme indicated for use in patients with Pompe disease (GAA deficiency). MYOZYME has been shown to improve ventilator-free survival in patients with infantile-onset Pompe disease as compared to an untreated historical control, whereas use of MYOZYME in patients with other forms of Pompe disease has not been adequately studied to assure safety and efficacy.

Important Safety Information

WARNING:

ANAPHYLAXIS, SEVERE ALLERGIC AND IMMUNE MEDIATED REACTIONS AND RISK OF CARDIORESPIRATORY FAILURE

Life-threatening anaphylactic reactions, severe allergic reactions and immune mediated reactions have been observed in some patients during MYOZYME infusions. Therefore, appropriate medical support should be readily available when MYOZYME is administered.

Risk of Cardiorespiratory Failure:

Patients with compromised cardiac or respiratory function may be at risk of serious acute exacerbation of their cardiac or respiratory compromise due to infusion reactions, and require additional monitoring.

Anaphylaxis and Allergic Reactions:

Anaphylaxis and severe allergic reactions have been reported in some patients during and up to three hours after MYOZYME infusion, some of which were IgE-mediated. Some of the reactions were life-threatening and included: anaphylactic shock, cardiac arrest, respiratory distress, hypotension, bradycardia, hypoxia, bronchospasm, throat tightness, dyspnea, angioedema, and urticaria. Interventions have included: cardiopulmonary resuscitation, mechanical ventilatory support, oxygen supplementation, intravenous (IV) fluids, hospitalization, treatment with inhaled beta-adrenergic agonists, epinephrine, and IV corticosteroids.

In clinical trials and postmarketing safety experience with MYOZYME, approximately 1% of patients developed anaphylactic shock and/or cardiac arrest during MYOZYME infusion that required life-support measures. In clinical trials and expanded access programs with MYOZYME, approximately 14% of patients treated with MYOZYME have developed allergic reactions that involved at least 2 of 3 body systems, cutaneous, respiratory or cardiovascular systems. These events included: Cardiovascular: hypotension, cyanosis, hypertension, tachycardia, ventricular extrasystoles, bradycardia, pallor, flushing, nodal rhythm, peripheral coldness; Respiratory: tachypnea, wheezing/bronchospasm, rales, throat tightness, hypoxia, dyspnea, cough, respiratory tract irritation, decreased oxygen saturation; Cutaneous: angioedema, urticaria, rash, erythema, periorbital edema, pruritus, hyperhidrosis, cold sweat, livedo reticularis.

If anaphylactic or other severe allergic reactions occur, immediate discontinuation of the administration of MYOZYME should be considered, and appropriate medical treatment should be initiated. Because of the potential for severe allergic reactions, appropriate medical support measures, including cardiopulmonary resuscitation equipment, should be readily available when MYOZYME is administered. The risks and benefits of re-administering MYOZYME following an anaphylactic or severe allergic reaction should be considered. Some patients have been rechallenged and have continued to receive MYOZYME under close clinical supervision. Extreme care should be exercised, with appropriate resuscitation measures available, if the decision is made to re-administer the product

Immune Mediated Reactions:

Severe cutaneous and systemic immune mediated reactions have been reported in postmarketing safety experience with MYOZYME in at least 2 patients, including ulcerative and necrotizing skin lesions, and possible type III immune mediated reactions. These reactions occurred several weeks to 3 years after initiation of MYOZYME infusions. Skin biopsy in one patient demonstrated deposition of anti-rh-GAA antibodies in the lesion. Another patient developed severe inflammatory arthropathy in association with fever and elevated erythrocyte sedimentation rate. Nephrotic syndrome secondary to membranous glomerulonephritis was observed in a few Pompe patients treated with alglucosidase alfa and who had persistently positive anti-rhGAA IgG antibody titers. In these patients renal biopsy was consistent with immune complex deposition. Patients improved following treatment interruption. It is therefore recommended to perform periodic urinalysis. Patients should be monitored for the development of systemic immune mediated reactions involving skin and other organs while receiving MYOZYME. If immune mediated reactions occur, discontinuation of the administration of MYOZYME should be considered, and appropriate medical treatment initiated. The risks and benefits of re-administering alglucosidase alfa following an immune mediated reaction should be considered. Some patients have successfully been rechallenged and have continued to receive alglucosidase alfa under close clinical supervision.

Risk of Acute Cardiorespiratory Failure:
Acute cardiorespiratory failure requiring intubation and inotropic support has been observed up to 72 hours after infusion with MYOZYME in infantile-onset Pompe disease patients with underlying cardiac hypertrophy, possibly associated with fluid overload with intravenous administration of MYOZYME. Patients with acute underlying respiratory illness, compromised cardiac function and/or sepsis may be at risk of serious exacerbation of their cardiac or respiratory compromise during infusions. Appropriate medical support and monitoring measures should be readily available during MYOZYME infusion, and infants with cardiac dysfunction may require prolonged observation times that should be individualized based on the needs of the patient.

Risk of Cardiac Arrhythmia and Sudden Cardiac Death During General Anesthesia for Central Venous Catheter Placement: Administration of general anesthesia can be complicated by the presence of severe cardiac and skeletal (including respiratory) muscle weakness. Therefore, caution should be used when administering general anesthesia for the placement of a central venous catheter intended for MYOZYME infusion. Ventricular arrhythmias and bradycardia, resulting in cardiac arrest or death, or requiring cardiac resuscitation or defibrillation have been observed in infantile-onset Pompe disease patients with cardiac hypertrophy during general anesthesia for central venous catheter placement.

Infusion Reactions:

Infusion reactions occurred in 20 of 39 (51%) of patients treated with MYOZYME in clinical studies. Severe infusion reactions reported in more than 1 patient in clinical studies and the expanded access program included: fever, decreased oxygen saturation, tachycardia, cyanosis and hypotension. Other infusion reactions reported in more than 1 patient in clinical studies and the expanded access program included: rash, flushing, urticaria, fever, cough, tachycardia, decreased oxygen saturation, vomiting, tachypnea, agitation, increased blood pressure/hypertension, cyanosis, irritability, pallor, pruritus, retching, rigors, tremor, hypotension, bronchospasm, erythema, face edema, feeling hot, headache, hyperhidrosis, increased lacrimation, livedo reticularis, nausea, periorbital edema, restlessness and wheezing. Some patients were pre-treated with antihistamines, antipyretics and/or steroids. Infusion reactions occurred in some patients after receiving antipyretics, antihistamines, or steroids. Infusion reactions may occur at any time during, or up to 2 hours after, the infusion of MYOZYME, and are more likely with higher infusion rates. The risks and benefits of re-administering MYOZYME following an anaphylactic or severe allergic reaction should be considered. Some patients have been rechallenged and have continued to receive MYOZYME under close clinical supervision. Extreme care should be exercised, with appropriate resuscitation measures available, if the decision is made to re-administer the product.

Patients with advanced Pompe disease may have compromised cardiac and respiratory function, which may predispose them to a higher risk of severe complications from infusion reactions. Therefore, these patients should be monitored more closely during administration of MYOZYME. Patients with an acute illness at the time of MYOZYME infusion may be at greater risk for infusion reactions. Careful consideration should be given to the patient’s clinical status prior to administration of MYOZYME. If an infusion reaction occurs, decreasing the infusion rate, temporarily stopping the infusion, and/or administration of antihistamines and/or antipyretics may ameliorate the symptoms. If severe infusion or allergic reactions occur, immediate discontinuation of the administration of MYOZYME should be considered, and appropriate medical treatment should be initiated.

Monitoring:

Laboratory Tests: Patients should be monitored for IgG antibody formation every 3 months for 2 years and then annually thereafter. Testing for IgG titers may also be considered if patients develop allergic or other immune mediated reactions. Patients who experience anaphylactic or allergic reactions may also be tested for IgE antibodies to alglucosidase alfa and other mediators of anaphylaxis.

Adverse Reactions:
The most serious adverse reactions reported with MYOZYME were anaphylactic reactions, acute cardiorespiratory failure, and cardiac arrest. Anaphylactic reactions have been reported during and within 3 hours after MYOZYME infusion. Acute cardiorespiratory failure has been observed in a few infantile-onset Pompe disease patients with underlying cardiac hypertrophy, possibly associated with fluid overload with intravenous administration of alglucosidase alfa. Infusion reactions, defined as an adverse reaction occurring during the infusion or within 2 hours after completion of the infusion, that occurred in more than 1 patient in clinical studies and the expanded access program include rash, flushing, urticaria, fever, cough, tachycardia, decreased oxygen saturations, vomiting, tachypnea, agitation, increased blood pressure/hypertension, cyanosis, irritability, pallor, pruritus, retching, rigors, tremor, hypotension, bronchospasm, erythema, face edema, feeling hot, headache, hyperhidrosis, increased lacrimation, livedo reticularis, nausea, periorbital edema, restlessness, and wheezing. In addition to the infusion reactions reported in clinical trials and expanded access programs, the following infusion reactions have been reported in patients during postmarketing use of MYOZYME: cardiac arrest, respiratory arrest, apnea, stridor, pharyngeal edema, peripheral edema, chest pain, chest discomfort, muscle spasm, fatigue and conjunctivitis. Additional adverse drug reactions included proteinuria and nephrotic syndrome.

Immunogenicity:
The majority of patients (34 of 38; 89%) in the two clinical trials tested positive for IgG antibodies to alglucosidase alfa. Most patients who develop antibodies do so within the first 3 months of exposure. There is evidence to suggest that patients developing sustained titers =12,800 of anti-alglucosidase alfa antibodies may have a poorer clinical response to treatment, or may lose motor function as antibody titers increase. Five patients with antibody titers = 12,800 at Week 12 had an average increase in clearance of 50% from Week 1 to Week 12. The effect of antibody development on the long-term efficacy of MYOZYME is not fully understood. However, CRIM-negative infants have shown poorer clinical response in the presence of high sustained IgG antibody titers and inhibitory and positive inhibitory antibodies. Patients who develop IgE antibodies to alglucosidase alfa appear to be at a higher risk for the occurrence of anaphylaxis and severe allergic reactions. Therefore, these patients should be monitored more closely during administration of MYOZYME.

心肌糖原沉积病【庞培氏(Pompe)病】

心肌糖厚沉积病由Pompe(1932)提出，为糖原合成和分解代谢中所需一系列酶的缺陷所致病变，是一种先天性代谢病，本病罕见，是引起婴儿心脏迅速增大的疾病之一，亦即所谓特发性心脏肥大。
【病因】
为糖原分解酶(如a-1，4-葡萄糖苷酶)的缺陷，不能分解为葡萄糖而造成糖原质和量的代谢障碍，使组织中的糖原累积，因此近年把这类疾患总称为糖原沉积病，由于受累的组织或器官不同，可区别为+或+ -型，绝大多数与常染色体隐性遗传有关。实际上可分为肝，心，肌肉三大类，如1型称为肝糖原沉积病（GSDI 亦称VonGierke病），2型为心肌糖原沉积病（GSDI，pampe病等）。3型即肌性糖原沉积病。
【病理】
由于组织中糖原积累，造成器官的肿大与功能不全，如心脏明显增大，主要是心室壁增厚，左室可厚达30毫米（正常为7~10毫米）糖原代谢了肌纤维，并有空泡形成，退行性坏死，但无炎症改变，同时可累及肝，肾和有纹肌等。
【临床情况】
1.病人出生后数周或数月发病，男女相等，病情发展快，常早年死于心力衰竭或呼吸道感染，但也有见于成人者。
2.心脏明显增大但一般无杂音，肌肉软弱无力，巨舌，面容与呆小症或伸舌痴愚相似，肝脾肿大常不明显。
3.胃纳差，呕吐，呼吸困难，紫绀，水肿以及营养不良，发育迟缓等表现。
4.心电图左心肥厚，T波倒置，S~T段下降，血液检查末梢白细胞的酸性麦芽糖酶（葡萄糖苷酶）的活性显著降低。
【X线表现】
心脏呈对称性的原形或球形明显扩大，主要是心室，不侵犯心房，搏动减弱，并可压迫左上支气管，引起左上叶肺不张，晚期有时合并肺郁血或肺炎的表现。
2，心血管造影，显示左心室壁增厚，血液循环正常，有时左肺动脉压升高。
【鉴别诊断】
应与心内膜弹力纤维增生症鉴别，二者X线表现大致相同，又可并存。其它如支气管肺炎伴心力衰竭，先天性心血管畸形，心肌炎等相区别。
参考资料：特殊病征临床X线诊断学

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原产地英文商品名:
MYOZYME 50MG VIAL
原产地英文药品名:
ALGLUCOSIDASE ALFA
中文参考商品译名:
MYOZYME 50毫克瓶
生产厂家中文参考译名:
Genzyme公司
生产厂家英文名:
Genzyme