二盐酸沙丙蝶呤—首个高苯丙氨酸血症治疗的新特药 2007年，美国FDA批准二盐酸沙丙蝶呤KUVAN(sapropterin dihydrochloride)上市治疗苯丙酮尿症. 本品是首个获准治疗苯丙酮尿症（PKU）的专一性治疗药 在临床研究中，二盐酸沙丙蝶呤显示有助于控制PKU患者的苯丙氨酸血浓度。本品适用于降低由与PKU相关的四氢生物蝶呤引起的高苯丙氨酸血症患者的苯丙氨酸血浓度，治疗期间需限苯丙氨酸饮食。为确定Kuvan的疗效，推荐初始剂量为二盐酸沙丙蝶呤一日1次10 mg/（kg·日），服用1月。若无效，药物剂量增至一日1次20 mg/（kg·日），服用1月；剂量可在5～20 mg/（kg·日）范围内调节。 二盐酸沙丙蝶呤系一合成的6R-BH4（四氢生物蝶呤），一种与苯丙氨酸羟化酶（PAH）结合代谢苯丙氨酸自然存在的辅酶。BioMarin Pharmaceutical公司和默克雪兰诺（Merck Serono）公司预测，Kuvan可用于治疗全球发达国家估计已诊断出约5万PKU患者的30%～50%。 KUVAN（沙丙蝶呤二盐酸盐）片剂，用于口服用途 KUVAN（沙丙蝶呤二盐酸盐）粉末，用于口服溶液 美国首次批准：2007 适应症和用法 Kuvan表示，以减少与高苯丙氨酸血症（HPA）患者血液中苯丙氨酸（Phe）的水平，由于tetrahydrobiopterin-（BH4-）响应苯丙酮尿症（PKU）苯丙氨酸羟化酶活性剂。 Kuvan是在同一个苯丙氨酸限制性饮食一起使用。 用法用量 起始剂量： 患者1个月到6年：Kuvan的推荐起始剂量为10毫克/千克采取每日一次。 患者7岁以上：Kuvan的推荐起始剂量为每日一次取10〜20毫克/公斤。 剂量调整： Kuvan的剂量可以在每天一次取5至20mg / kg的范围内进行调整。血苯丙氨酸必须定期监测。 指导患者采取一餐。 整体或混合于少量的软的食物或溶解在推荐液体之后吞服片剂。混合粉末在少量的软的食物或溶解在推荐液体后吞咽口服溶液。 剂型和规格 片，100毫克 散口服液，100毫克，500毫克 修订：2015/07 HIGHLIGHTS OF PRESCRIBING INFORMATION These highlights do not include all the information needed to use KUVAN safely and effectively. See full prescribing information for KUVAN. KUVAN (sapropterin dihydrochloride) tablets, for oral use KUVAN (sapropterin dihydrochloride) powder, for oral solution Initial U.S. Approval: 2007 INDICATIONS AND USAGE Kuvan is a phenylalanine hydroxylase activator indicated to reduce blood phenylalanine (Phe) levels in patients with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin‑ (BH4‑) responsive Phenylketonuria (PKU). Kuvan is to be used in conjunction with a Phe‑restricted diet (1). DOSAGE AND ADMINISTRATION Starting dose: Patients 1 month to 6 years: The recommended starting dose of Kuvan is 10 mg/kg taken once daily (2.1, 5.3). Patients 7 years and older: The recommended starting dose of Kuvan is 10 to 20 mg/kg taken once daily (2.1). Dose Adjustment: Doses of Kuvan may be adjusted in the range of 5 to 20 mg/kg taken once daily. Blood Phe must be monitored regularly (2.1). Instruct patients to take with a meal. Swallow tablets whole or after mixing in a small amount of soft foods or dissolving in recommended liquid.  Swallow oral solution after mixing powder in a small amount of soft foods or dissolving in recommended liquids. DOSAGE FORMS AND STRENGTHS Tablets, 100 mg (3) Powder for Oral Solution, 100 mg, 500 mg (3) CONTRAINDICATIONS None (4). WARNINGS AND PRECAUTIONS Hypersensitivity reactions including anaphylaxis have occurred (5.1). Gastritis was reported in clinical trials. Monitor patients for signs of gastritis (5.2). Children younger than 7 years treated with Kuvan doses of 20 mg/kg per day are at increased risk for low levels of blood Phe compared with children 7 years and older (5.3). Monitor blood Phe levels during treatment to ensure adequate blood Phe control (5.4). Identify non-responders to Kuvan treatment: Not all patients with PKU respond to treatment with Kuvan (5.5). Treat all patients with a Phe-restricted diet: The initiation of Kuvan therapy does not eliminate the need for ongoing dietary management (5.6). Monitor liver function tests in patients with liver impairment who are receiving Kuvan (5.7). Monitor patients when co-administering Kuvan with medications known to inhibit folate metabolism, or with levodopa. Monitor patients for hypotension when co-administering Kuvan with medications known to affect nitric oxide-mediated vasorelaxation (5.8, 5.9, 5.10). There have been post-marketing reports of hyperactivity with administration of Kuvan. Monitor patients for hyperactivity (5.11). ADVERSE REACTIONS The most common adverse reactions (incidence ≥4%) in patients treated with Kuvan are headache, rhinorrhea, pharyngolaryngeal pain, diarrhea, vomiting, cough, and nasal congestion (6.1). To report SUSPECTED ADVERSE REACTIONS, contact BioMarin Pharmaceutical Inc. at 1-866-906-6100, or FDA at 1-800-FDA-1088 orwww.fda.gov/medwatch. See 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling. Revised: 7/2015 FULL PRESCRIBING INFORMATION: CONTENTS* 1.  INDICATIONS AND USAGE Kuvan® (sapropterin dihydrochloride) is indicated to reduce blood phenylalanine (Phe) levels in patients with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin- (BH4-) responsive Phenylketonuria (PKU). Kuvan is to be used in conjunction with a Phe-restricted diet. 2.  DOSAGE AND ADMINISTRATION 2.1  Dosage Patients 1 month to 6 years: The recommended starting dose of Kuvan is 10 mg/kg taken once daily [see Warnings and Precautions (5.3)]. Patients 7 years and older: The recommended starting dose of Kuvan is 10 to 20 mg/kg taken once daily. If a 10 mg/kg per day starting dose is used, then response to therapy is determined by change in blood Phe following treatment with Kuvan at 10 mg/kg per day for a period of up to 1 month. Blood Phe levels should be checked after 1 week of Kuvan treatment and periodically for up to a month. If blood Phe does not decrease from baseline at 10 mg/kg per day, the dose may be increased to 20 mg/kg per day. Patients whose blood Phe does not decrease after 1 month of treatment at 20 mg/kg per day are non-responders and treatment with Kuvan should be discontinued in these patients. If a 20 mg/kg per day starting dose is used, then response to therapy is determined by change in blood Phe following treatment with Kuvan at 20 mg/kg per day for a period of 1 month. Blood Phe levels should be checked after 1 week of Kuvan treatment and periodically during the first month. Treatment should be discontinued in patients who do not respond to Kuvan. Once responsiveness to Kuvan has been established, the dosage may be adjusted within the range of 5 to 20 mg/kg per day according to response to therapy. Periodic blood Phe monitoring is recommended to assess blood Phe control [see Warnings and Precautions (5.3, 5.6)]. 2.2  Administration Kuvan is available as tablets and as powder for oral solution. Kuvan should be taken orally with a meal to increase absorption, preferably at the same time each day. A missed dose should be taken as soon as possible, but two doses should not be taken on the same day. 2.3 Instructions for Use Kuvan Tablets Kuvan tablets may be swallowed either as whole tablets or dissolved in 120 to 240 mL of water or apple juice and taken orally within 15 minutes of dissolution. It may take a few minutes for the tablets to dissolve. To make the tablets dissolve faster, tablets may be stirred or crushed. The tablets may not dissolve completely. Patients may see small pieces floating on top of the water or apple juice. This is normal and safe for patients to swallow. If after drinking the medicine patients still see pieces of the tablet in the container, more water or apple juice can be added to make sure all of the medicine is consumed. Kuvan tablets may also be crushed and then mixed in a small amount of soft foods such as apple sauce or pudding. Kuvan Powder for Oral Solution Kuvan powder for oral solution should be dissolved in 120 to 240 mL of water or apple juice and taken orally within 30 minutes of dissolution. Kuvan powder for oral solution may also be stirred in a small amount of soft foods such as apple sauce or pudding.  Empty the contents of the packet(s) in water, apple juice, or a small amount of soft foods and mix thoroughly. The powder should dissolve completely. For infants weighing 10 kg or less, Kuvan can be dissolved in as little as 5 mL of water or apple juice and a portion of this solution corresponding to a 10 mg/kg dose may be administered orally via an oral dosing syringe. Table 1 provides dosing information for infants at the recommended starting dose of 10 mg/kg per day. Refer to Table 2 for dosing information at 20 mg/kg per day if dosage adjustment is needed. Table 1: 10 mg/kg per day Dosing Table for Infants Weighing 10 kg or less Patient Weight (kg) Starting Dose: 10 mg/kg per day* Dose (mg) # Kuvan 100 mg Packets Dissolved† Dilution Volume (mL)‡ Administered Dose volume (mL)§   1 10 1 10  1   2 20 1 10  2   3 30 1 10  3   4 40 1 10  4   5 50 1 10  5   6 60 1 5  3   7 70 1 5   3.5   8 80 1 5  4   9 90 1 5 4.5 10 100 1 5 5 Starting dose for infants is 10 mg/kg per day. Dosing information for 20 mg/kg per day is provided in Table 2. Powder for oral solution provided in single use packets containing 100 mg Kuvan per packet Volume of water or apple juice to dissolve Kuvan Powder for Oral Solution. Discard remainder of mixture after volume to be administered is drawn. Table 2: 20 mg/kg per day Dosing Table for Infants Weighing 10 kg or less Patient Weight (kg) 20 mg/kg per day Dose (mg) # Kuvan 100 mg  Packets* Dissolved Dilution Volume (mL)† Administered Dose volume (mL)§   1   20 1 5   1   2   40 1 5   2   3   60 1 5   3   4   80 1 5   4   5 100 1 5   5   6 120 2 5   3   7 140 2 5   3.5   8 160 2 5   4   9 180 2 5   4.5 10 200 2 5 5 Powder for oral solution provided in single use packets containing 100 mg Kuvan per packet Volume of water or apple juice to dissolve Kuvan Powder for Oral Solution. Discard remainder of mixture after volume to be administered is drawn. 3. DOSAGE FORMS AND STRENGTHS Kuvan tablets are for oral use. Each tablet contains 100 mg of sapropterin dihydrochloride (equivalent to 76.8 mg of sapropterin base). Tablets are round, off-white to light yellow, mottled, and debossed with “177”. Kuvan powder for oral solution is available as a unit dose packet containing 100 mg of sapropterin dihydrochloride (equivalent to 76.8 mg of sapropterin base)  and as a unit dose packet containing 500 mg of sapropterin dihydrochloride (equivalent to 384 mg of sapropterin base). The powder is off-white to yellow in color. 4. CONTRAINDICATIONS None. 5. WARNINGS AND PRECAUTIONS 5.1 Hypersensitivity Reactions Including Anaphylaxis Kuvan is not recommended in patients with a history of anaphylaxis to Kuvan. Hypersensitivity reactions, including anaphylaxis and rash, have occurred [see Adverse Reactions (6.2)]. Signs of anaphylaxis include wheezing, dyspnea, coughing, hypotension, flushing, nausea, and rash. Discontinue treatment with Kuvan in patients who experience anaphylaxis and initiate appropriate medical treatment. Continue dietary Phe restrictions in patients who experience anaphylaxis. 5.2 Gastritis During clinical studies, gastritis was reported as a serious adverse reaction. Monitor patients for signs and symptoms of gastritis. 5.3 Hypophenylalaninemia In clinical trials, some patients have experienced low blood Phe levels. Children younger than 7 years treated with Kuvan doses of 20 mg/kg per day are at increased risk for low levels of blood Phe compared with patients 7 years and older [see Adverse Reactions (6.1)]. 5.4 Monitor Blood Phe Levels During Treatment Treatment with Kuvan should be directed by physicians knowledgeable in the management of PKU. Prolonged elevations in blood Phe levels in patients with PKU can result in severe neurologic damage, including severe mental retardation, microcephaly, delayed speech, seizures, and behavioral abnormalities. Conversely, prolonged levels of blood Phe that are too low have been associated with catabolism and protein breakdown. Active management of dietary Phe intake while taking Kuvan is required to ensure adequate Phe control and nutritional balance. Monitor blood Phe levels during treatment to ensure adequate blood Phe level control. Frequent blood monitoring is recommended in the pediatric population [see Patient Counseling Information (17)]. 5.5 Identify Non-Responders to Kuvan Treatment Not all patients with PKU respond to treatment with Kuvan. In two clinical trials at a dose of 20 mg/kg per day, 56% to 75% of pediatric PKU patients responded to treatment with Kuvan, and in one clinical trial at a dose of 10 mg/kg per day, 20% of adult and pediatric PKU patients responded to treatment with Kuvan [see Clinical Studies (14.1)].  Response to treatment cannot be pre-determined by laboratory testing (e.g., molecular testing), and can only be determined by a therapeutic trial of Kuvan [see Dosage and Administration (2.1)]. 5.6 Treat All Patients with  a Phe-restricted Diet All patients with PKU who are being treated with Kuvan should also be treated with a Phe-restricted diet. 5.7 Monitor Patients with Hepatic Impairment Patients with liver impairment have not been evaluated in clinical trials with Kuvan. Monitor liver function tests in patients with liver impairment who are receiving Kuvan because hepatic damage has been associated with impaired Phe metabolism. 5.8 Monitor Patients when Co-administering Kuvan and Medications Known to Inhibit Folate Metabolism Co-administering Kuvan with drugs known to affect folate metabolism (e.g., methotrexate) and their derivatives may require more frequent monitoring of blood Phe levels because these drugs can decrease endogenous BH4 levels by inhibiting the enzyme dihydropteridine reductase (DHPR). 5.9 Monitor Patients for Hypotension when Co-administering Kuvan and Drugs Known to Affect Nitric Oxide-Mediated Vasorelaxation Monitor blood pressure when administering Kuvan with drugs that affect nitric oxide‑mediated vasorelaxation (e.g., PDE-5 inhibitors such as sildenafil, vardenafil, or tadalafil), because both sapropterin dihydrochloride and PDE-5 inhibitors may induce vasorelaxation. The additive effect of sapropterin and PDE-5 inhibitor co-administration could lead to a reduction in blood pressure; however, the combined use of these medications has not been evaluated in humans. In animal studies, orally administered Kuvan in combination with a PDE-5 inhibitor had no effect on blood pressure. 5.10 Monitor Patients when Co-administering Kuvan and Levodopa Caution should be used with the administration of Kuvan to patients who are receiving levodopa. In a 10-year post-marketing safety surveillance program for a non-PKU indication using another formulation of the same active ingredient (sapropterin), 3 patients with underlying neurologic disorders experienced convulsions, exacerbation of convulsions, over-stimulation, or irritability during co-administration of levodopa and sapropterin. Monitor for change in neurologic status. 5.11 Monitor Patients for Hyperactivity In the post-marketing safety surveillance program for PKU, 2 patients experienced hyperactivity with administration of Kuvan. Monitor patients for hyperactivity. 6.  ADVERSE REACTIONS 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to the rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.  PKU Clinical Studies The safety of Kuvan was evaluated in 6 clinical studies in patients with PKU (aged 1 month to 50 years) [see Clinical Studies (14.1)].  In Studies1-4 (controlled and uncontrolled studies), 579 patients with PKU aged 4 to 49 years received Kuvan in doses ranging from 5 to 20 mg/kg per day for lengths of treatment ranging from 1 to 164 weeks. The patient population was evenly distributed in gender, and approximately 95% of patients were Caucasian.  The most common adverse reactions (≥4% of patients) were headache, rhinorrhea, pharyngolaryngeal pain, diarrhea, vomiting, cough, and nasal congestion. The data described in Table 3 reflect exposure of 74 patients with PKU to Kuvan at doses of 10 to 20 mg/kg per day for 6 to 10 weeks in two double-blind, placebo-controlled clinical trials (Studies 2 and 4). Table 3 enumerates adverse reactions occurring in at least 4% of patients treated with Kuvan in the double-blind, placebo-controlled clinical trials described above. Table 3: Summary of Adverse Reactions  Occurring in ≥4% of Patients in Placebo-Controlled Clinical Studies with Kuvan MedDRA Preferred Term Treatment Kuvan (N=74) Placebo (N=59) No. Patients (%) No. Patients (%) Headache 11 (15) 8 (14) Rhinorrhea 8 (11) 0 Pharyngolaryngeal pain 7(10) 1 (2) Diarrhea 6 (8) 3 (5) Vomiting 6 (8) 4 (7) Cough 5 (7) 3 (5) Nasal congestion 3 (4) 0 In open-label, uncontrolled clinical trials (Studies 1 and 3)  all patients received Kuvan in doses of 5 to 20 mg/kg per day, adverse reactions were similar in type and frequency to those reported in the double-blind, placebo-controlled clinical trials [see Clinical Studies (14.1)]. In Study 5, 65 pediatric patients with PKU aged 1 month to 6 years received Kuvan 20 mg/kg per day for 6 months.  Adverse reactions in these patients were similar in frequency and type as those seen in other Kuvan clinical trials except for an increased incidence of low Phe levels. Twenty-five percent (16 out of 65) of patients developed Phe levels below normal for age [see Warnings and Precautions (5.3), Pediatric Use (8.4), and Clinical Studies (14.1)]. In Study 6, a long term, open-label, extension study of 111 patients aged 4 to 50 years, receiving Kuvan in doses ranging from 5 to 20 mg/kg per day, adverse reactions were similar in type and frequency to those reported in the previous clinical studies.  Fifty-five patients received Kuvan both as dissolved and intact tablets.  There were no notable differences in the incidence or severity of adverse reactions between the two methods of administration.  The mean (± SD) exposure to sapropterin for the entire study population was 659 ± 221 days (maximum 953 days). Safety Experience from Clinical Studies for Non-PKU Indications Approximately 800 healthy volunteers and patients with disorders other than PKU, some of whom had underlying neurologic disorders or cardiovascular disease, have been administered a different formulation of the same active ingredient (sapropterin) in approximately 19 controlled and uncontrolled clinical trials. In these clinical trials, subjects were administered sapropterin at doses ranging from 1 to 100 mg/kg per day for lengths of exposure from 1 day to 2 years. Serious and severe adverse reactions (regardless of causality) during sapropterin administration were convulsions, exacerbation of convulsions [see Warnings and Precautions (5.10)], dizziness, gastrointestinal bleeding, post-procedural bleeding, headache, irritability, myocardial infarction, overstimulation, and respiratory failure. Common adverse reactions were headache, peripheral edema, arthralgia, polyuria, agitation, dizziness, nausea, pharyngitis, abdominal pain, upper abdominal pain, and upper respiratory tract infection. 6.2  Post-Marketing Experience The following adverse reactions have been identified during post-approval use of Kuvan. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish causal relationship to drug exposure. In worldwide marketing experience, the most common adverse reactions due to Kuvan are oropharyngeal pain, pharyngitis, esophageal pain, gastritis, dyspepsia, abdominal pain, nausea and vomiting. Hypersensitivity reactions including anaphylaxis and rash have been reported. Most hypersensitivity reactions occurred within several days of initiating treatment. Two cases of hyperactivity have been reported, including one case in a patient who received an accidental overdose of Kuvan [see Warnings and Precautions (5.1, 5.11)].  7.  DRUG INTERACTIONS No drug interaction studies were performed. 8.  USE IN SPECIFIC POPULATIONS 8.1  Pregnancy Pregnancy Category C A patient registry has been established that collects data on women who are treated with Kuvan during pregnancy. For more information regarding the registry program call 1-866-906-6100. Risk Summary There are no adequate and well-controlled studies with Kuvan in pregnant women.  An embryo-fetal development study with sapropterin dihydrochloride in rats using oral doses up to 3 times the maximum recommended human dose (MRHD) given during the period of organogenesis showed no effects. In a rabbit study using oral administration of sapropterin dihydrochloride during the period of organogenesis, a rare defect, holoprosencephaly, was noted at 10 times the MRHD. Kuvan should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Clinical Considerations Disease-associated maternal and/or embryofetal risk Available data from the Maternal Phenylketonuria Collaborative Study on 468 pregnancies and 331 live births in PKU‑affected women demonstrated that uncontrolled Phe levels above 600 µmol/L are associated with a very high incidence of neurological, cardiac, facial dysmorphism, and growth anomalies. Good dietary control of Phe levels during pregnancy is essential to reduce the incidence of Phe-induced teratogenic effects. Animal Data No effects on embryo-fetal development were observed in a reproduction study in rats using oral doses of up to 400 mg/kg per day sapropterin dihydrochloride (about 3 times the MRHD of 20 mg/kg per day, based on body surface area) administered during the period of organogenesis. However, in a rabbit reproduction study, oral administration of a maximum dose of 600 mg/kg per day (about 10 times the MRHD, based on body surface area) during the period of organogenesis was associated with a non-statistically significant increase in the incidence of holoprosencephaly in two high dose-treated litters (4 fetuses), compared to one control-treated litter (1 fetus).  8.3  Nursing Mother It is not known whether Kuvan is present in human milk. Sapropterin is present in the milk of intravenously, but not orally, treated lactating rats. The developmental and health benefits of human milk feeding should be considered along with the mother’s clinical need for Kuvan and any potential adverse effects on the human milk-fed child from the drug or from the underlying maternal condition. Exercise caution when Kuvan is administered to a nursing woman. 8.4  Pediatric Use Pediatric patients with PKU, ages 1 month to 16 years, have been treated with Kuvan in clinical trials [see Clinical Studies (14.1)].  The efficacy and safety of Kuvan have not been established in neonates.  The safety of Kuvan has been established in children younger than 4 years in trials of 6 months duration and in children 4 years and older in trials of up to 3 years in length [see Adverse Reactions (6.1)]. In children aged 1 month and older, the efficacy of Kuvan has been demonstrated in trials of 6 weeks or less in duration [see Clinical Studies (14.1)].  In a multicenter, open-label, single arm study, 57 patients aged 1 month to 6 years who were defined as Kuvan responders after 4 weeks of Kuvan treatment and Phe dietary restriction were treated for 6 months with Kuvan at 20 mg/kg per day.  The effectiveness of Kuvan alone on reduction of blood Phe levels beyond 4 weeks could not be determined due to concurrent changes in dietary Phe intake during the study.  Mean (±SD) blood Phe values over time for patients aged 1 month to <2 years and 2 to <7 years are shown in Figure 1. 8.5  Geriatric Use Clinical studies of Kuvan in patients with PKU did not include patients aged 65 years and older. It is not known whether these patients respond differently than younger patients. 8.6  Patients with Renal Impairment Patients with renal impairment have not been evaluated in clinical trials. Monitor patients who have renal impairment carefully when they are receiving Kuvan. 10.  OVERDOSAGE Two unintentional overdosages with Kuvan have been reported. One adult patient in a Kuvan clinical trial received a single Kuvan dose of 4,500 mg (36 mg/kg) instead of 2,600 mg (20 mg/kg). The patient reported mild headache and mild dizziness immediately after taking the dose; both symptoms resolved within 1 hour with no treatment intervention. There were no associated laboratory test abnormalities. The patient suspended therapy for 24 hours and then restarted Kuvan with no reports of abnormal signs or symptoms. In postmarketing, one pediatric patient received Kuvan doses of 45 mg/kg per day instead of 20 mg/kg per day. The patient reported hyperactivity that began at an unspecified time after overdose and resolved after the Kuvan dose was reduced to 20 mg/kg per day.  In a clinical study to evaluate the effects of Kuvan on cardiac repolarization, a single supra-therapeutic dose of 100 mg/kg (5 times the maximum recommended dose) was administered to 54 healthy adults. No serious adverse reactions were reported during the study. The only adverse reactions reported in more than 1 subject who received the supra-therapeutic dose were upper abdominal pain (6%) and dizziness (4%). A dose-dependent shortening of the QT interval was observed [see Clinical Pharmacology (12.2)]. Patients should be advised to notify their physicians in cases of overdose. 11.  DESCRIPTION Kuvan (sapropterin dihydrochloride) is an orally administered Phenylalanine Hydroxylase activator (or PAH activator). Sapropterin dihydrochloride, the active pharmaceutical ingredient in Kuvan, is a synthetic preparation of the dihydrochloride salt of naturally occurring tetrahydrobiopterin (BH4). Sapropterin dihydrochloride is an off-white to light yellow crystals or crystalline powder. The chemical name of sapropterin dihydrochloride is (6R)-2-amino-6-[(1R,2S)-1,2-dihydroxypropyl]-5,6,7,8-tetrahydro-4(1H)-pteridinone dihydrochloride and the molecular formula is C9H15N5O3·2HCl with a molecular weight of 314.17. Sapropterin dihydrochloride has the following structural formula: Kuvan is supplied as tablets and powder for oral solution containing 100 mg of sapropterin dihydrochloride (equivalent to 76.8 mg of sapropterin base). Kuvan is also supplied as powder for oral solution containing 500 mg of sapropterin dihydrochloride (equivalent to 384 mg of sapropterin base). Tablets are round, off-white to light yellow, mottled, and debossed with “177”. Each tablet contains the following inactive ingredients: ascorbic acid (USP), crospovidone (NF), dibasic calcium phosphate (USP), D-mannitol (USP), riboflavin (USP), and sodium stearyl fumarate (NF). Kuvan powder for oral solution is off-white to yellow in color. Each unit dose packet contains the following inactive ingredients: ascorbic acid (USP), D-mannitol (USP), potassium citrate (USP), and sucralose (NF).%3 12.  CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Kuvan is a synthetic form of BH4, the cofactor for the enzyme phenylalanine hydroxylase (PAH). PAH hydroxylates Phe through an oxidative reaction to form tyrosine. In patients with PKU, PAH activity is absent or deficient. Treatment with BH4 can activate residual PAH enzyme activity, improve the normal oxidative metabolism of Phe, and decrease Phe levels in some patients. 12.2 Pharmacodynamics In PKU patients who are responsive to BH4 treatment, blood Phe levels decrease within 24 hours after a single administration of sapropterin dihydrochloride, although maximal effect on Phe level may take up to a month, depending on the patient. A single daily dose of Kuvan is adequate to maintain stable blood Phe levels over a 24-hour period. Twelve patients with blood Phe levels ranging from 516 to 986 μmol/L (mean 747 ± 153 μmol/L) were assessed with 24‑hour blood Phe level monitoring following a daily morning dose of 10 mg/kg per day. The blood Phe level remained stable during a 24‑hour observation period. No substantial increases in blood Phe levels were observed following food intake throughout the 24-hour period. Kuvan dose-response relationship was studied in an open-label, forced titration study at doses of 5 mg/kg per day, then 20 mg/kg per day, and then 10 mg/kg per day (Study 3) [see Clinical Studies (14.1)]. Individual blood Phe levels were highly variable among patients. The mean blood Phe level observed at the end of each 2-week dosing period decreased as the dose of sapropterin dihydrochloride increased, demonstrating an inverse relationship between the dose of sapropterin dihydrochloride and mean blood Phe levels.  Effects of Kuvan on the QTc interval A thorough QTc study was performed in 56 healthy adults.  This randomized, placebo and active controlled crossover study was conducted to determine if a single supra-therapeutic (100 mg/kg) dose of Kuvan or a single therapeutic dose (20 mg/kg) of Kuvan had an effect on cardiac repolarization. In this study, Kuvan was administered after dissolving tablets in water under fed condition. This study demonstrated a dose-dependent shortening of the QT interval. The maximum placebo-subtracted mean change from baseline of the QTc interval was -3.69 and -8.32 ms (lower bound of 90% CI: -5.3 and -10.6 ms) at 20 and 100 mg/kg, respectively.   12.3 Pharmacokinetics Studies in healthy volunteers have shown comparable absorption of sapropterin when tablets are dissolved in water or orange juice and taken under fasted conditions. Administration of dissolved tablets after a high-fat/high-calorie meal resulted in mean increases in Cmax of 84% and AUC of 87% (dissolved in water). However, there was extensive variability in individual subject values for Cmax and AUC across the different modes of administration and meal conditions. In the clinical trials of Kuvan, drug was administered in the morning as a dissolved tablet without regard to meals. The mean elimination half-life in PKU patients was approximately 6.7 hours (range 3.9 to 17 hr), comparable with values seen in healthy subjects (range 3.0 to 5.3 hr).  A study in healthy adults with 10 mg/kg of Kuvan demonstrated the absorption via intact tablet administration was 40% greater than via dissolved tablet administration under fasted conditions based on AUC0-t. The administration of intact tablets under fed conditions resulted in an approximately 43% increase in the extent of absorption compared to fasted conditions based on AUC0-t. Population pharmacokinetic analysis of sapropterin including patients from 1 month to 49 years of age showed that body weight is the only covariate substantially affecting clearance or distribution volume (see Table 4). Pharmacokinetics in patients >49 years of age have not been studied. Table 4.  Apparent Plasma Clearance by Age Parameter 0 to <1 yr* (N=10) 1 to <6 yr* (N=57) 6 to <12 yr† (N=23) 12 to <18 yr† (N=24) ≥18 yr† (N=42) CL/F (L/hr/kg) Mean ± SD (Median) 81.5 ± 92.4 (53.6) 50.7 ± 20.1 (48.4) 51.7 ± 21.9 (47.4) 39.2 ± 9.3 (38.3) 37.9 ± 20.2 (31.8) Evaluated at 20 mg/kg per day dose Evaluated at 5, 10, or 20 mg/kg per day doses Metabolism Sapropterin is a synthetic form of tetrahydrobiopterin (BH4) and is expected to be metabolized and recycled by the same endogenous enzymes. In vivo endogenous BH4 is converted to quinoid dihydrobiopterin and is metabolized to dihydrobiopterin and biopterin. The enzymes dihydrofolate reductase and dihydropteridine reductase are responsible for the metabolism and recycling of BH4. 13. NONCLINICAL TOXICOLOGY 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility A 2-year carcinogenicity study was conducted in F-344 rats, and a 78-week carcinogenicity study was conducted in CD-1 mice. In the 104-week oral carcinogenicity study in rats, sapropterin dihydrochloride doses of 25, 80, and 250 mg/kg per day (0.2, 0.7, and 2 times the maximum recommended human dose of 20 mg/kg per day, respectively, based on body surface area) were used. In the 78-week oral carcinogenicity study in mice, sapropterin dihydrochloride doses of 25, 80, and 250 mg/kg per day (0.1, 0.3, and 2 times the recommended human dose, respectively, based on body surface area) were used. In the 2‑year rat carcinogenicity study, there was a statistically significant increase in the incidence of benign adrenal pheochromocytoma in male rats treated with the 250 mg/kg per day (about 2 times the maximum recommended human dose, based on body surface area) dose, as compared to vehicle treated rats. The mouse carcinogenicity study showed no evidence of a carcinogenic effect, but the study was not ideal due to its duration of 78 instead of 104 weeks. Sapropterin dihydrochloride was genotoxic in the in vitro Ames test at concentrations of 625 µg (TA98) and 5000 µg (TA100) per plate, without metabolic activation. However, no genotoxicity was observed in the in vitro Ames test with metabolic activation. Sapropterin dihydrochloride was genotoxic in the in vitro chromosomal aberration assay in Chinese hamster lung cells at concentrations of 0.25 and 0.5 mM. Sapropterin dihydrochloride was not mutagenic in the in vivo micronucleus assay in mice at doses up to 2000 mg/kg per day (about 8 times the maximum recommended human dose of 20 mg/kg per day, based on body surface area). Sapropterin dihydrochloride, at oral doses up to 400 mg/kg per day (about 3 times the maximum recommended human dose, based on body surface area) was found to have no effect on fertility and reproductive function of male and female rats. 14.  CLINICAL STUDIES 14.1  Clinical Studies in PKU The efficacy of Kuvan was evaluated in five clinical studies in patients with PKU. Study 1 was a multicenter, open-label, uncontrolled clinical trial of 489 patients with PKU, ages 8 to 48 years (mean 22 years), who had baseline blood Phe levels ≥ 450 μmol/L and who were not on Phe-restricted diets. All patients received treatment with Kuvan 10 mg/kg per day for 8 days. For the purposes of this study, response to Kuvan treatment was defined as a ≥ 30% decrease in blood Phe from baseline. At Day 8, 96 patients (20%) were identified as responders. Study 2 was a multicenter, double-blind, placebo-controlled study of 88 patients with PKU who responded to Kuvan in Study 1. After a washout period from Study 1, patients were randomized equally to either Kuvan 10 mg/kg per day (N=41) or placebo (N=47) for 6 weeks. Efficacy was assessed by the mean change in blood Phe level from baseline to Week 6 in the Kuvan-treated group as compared to the mean change in the placebo group. The results showed that at baseline, the mean (±SD) blood Phe level was 843 (±300) μmol/L in the Kuvan-treated group and 888 (±323) μmol/L in the placebo group. At Week 6, the Kuvan treated group had a mean (±SD) blood Phe level of 607 (±377) μmol/L, and the placebo group had a mean blood Phe level of 891 (±348) μmol/L. At Week 6, the Kuvan- and placebo treated groups had mean changes in blood Phe level of –239 and 6 μmol/L, respectively (mean percent changes of –29% (±32) and 3% (±33), respectively). The difference between the groups was statistically significant (p < 0.001) (Table 5). Table 5: Blood Phe Results in Study 2 Sapropterin (N=41) Placebo (N=47) Baseline Blood Phe Level* (μmol/L) Mean (±SD) 843 (±300) 888 (±323) Percentiles (25th, 75th) 620, 990 618, 1141 Week 6 Blood Phe Level (μmol/L) Mean (±SD) 607 (±377) 891 (±348) Percentiles (25th, 75th) 307, 812 619, 1143 Mean Change in Blood Phe From Baseline to Week 6 (μmol/L) Adjusted Mean (±SE)† -239 (±38) 6 (±36) Percentiles (25th, 75th) -397, -92 -96, 93 Mean Percent Change in Blood Phe From Baseline to Week 6 Mean (±SD) - 29 (±32) 3 (±33) Percentiles (25th, 75th) -61, -11 -13, 12 The mean baseline levels shown in this table represent the mean of 3 pretreatment levels (Wk -2, Wk -1, and Wk 0). Treatment with Kuvan or placebo started at Wk 0. p-value < 0.001, adjusted mean and standard error from an ANCOVA model with change in blood Phe level from baseline to Week 6 as the response variable, and both treatment group and baseline blood Phe level as covariates. Change in blood Phe was noted in the Kuvan-treated group at Week 1 and was sustained through Week 6 (Figure 2). Figure 2 Study 3 was a multicenter, open-label, extension study in which 80 patients who responded to Kuvan treatment in Study 1 and completed Study 2 underwent 6 weeks of forced dose-titration with 3 different doses of Kuvan. Treatments consisted of 3 consecutive 2-week courses of Kuvan at doses of 5, then 20, and then 10 mg/kg per day. Blood Phe level was monitored after 2 weeks of treatment at each dose level. At baseline, mean (±SD) blood Phe was 844 (±398) μmol/L. At the end of treatment with 5, 10, and 20 mg/kg per day, mean (±SD) blood Phe levels were 744 (±384) μmol/L, 640 (±382) μmol/L, and 581 (±399) μmol/L, respectively (Table 6). Table 6: Blood Phe Results From Forced Dose-Titration in Study 3 Kuvan Dose Level (mg/kg per day) No. of Patients Mean (±SD) Blood Phe Level (μmol/L) Mean Changes (±SD) in Blood Phe Level From Week 0 (μmol/L) Baseline (No Treatment) 80 844 (±398) — 5 80 744 (±384) ‑100 (±295) 10 80 640 (±382) ‑204 (±303) 20 80 581 (±399) -263 (±318) Study 4 was a multicenter study of 90 pediatric patients with PKU, ages 4 to 12 years, who were on Phe‑restricted diets and who had blood Phe levels ≤480 μmol/L at screening. All patients were treated with open-label Kuvan 20 mg/kg per day for 8 days. Response to Kuvan was defined as a ≥30% decrease in blood Phe from baseline at Day 8. At Day 8, 50 patients (56%) had a ≥30% decrease in blood Phe. Study 5 was an open label, single arm, multicenter trial in 93 pediatric patients with PKU, aged 1 month to 6 years, who had Phe levels greater than or equal to 360 μmol/L at screening.   All patients were treated with Kuvan at 20 mg/kg per day and maintained on a Phe-restricted diet.   At Week 4, 57 patients (61%) were identified as responders (defined as ≥ 30% decreased in blood Phe from baseline) (see Figure 1 section 8.4). 16.  HOW SUPPLIED/STORAGE AND HANDLING Kuvan tablets, 100 mg, are round, off-white to light yellow, mottled, and debossed with “177”. The tablets are supplied as follows: NDC 68135-300-02    Bottle of 120 tablets Kuvan powder for oral solution is an off-white to yellow powder packaged in unit dose packets as follows: 100 mg Kuvan per packet: NDC 68135-301-22    Carton of 30 unit dose packets NDC 68135-301-11    Single unit dose packet 500 mg Kuvan per packet: NDC 68135-482-11    Carton of 30 unit dose packets NDC 68135-482-10    Single unit dose packet Storage Store Kuvan tablets at 20ºC to 25ºC (68ºF to 77ºF); excursions allowed between 15ºC to 30ºC (59ºF to 86ºF) [see USP Controlled Room Temperature]. Keep container tightly closed. Protect from moisture. Store Kuvan powder for oral solution at 20ºC to 25ºC (68ºF to 77ºF); excursions allowed between 15ºC to 30ºC (59ºF to 86ºF) [see USP Controlled Room Temperature]. Protect from moisture. Manufactured for: BioMarin Pharmaceutical Inc. Novato, CA 94949 17.  PATIENT COUNSELING INFORMATION See FDA-approved patient labeling (Patient Information and Instructions for Use) Patients should be advised of the following information before beginning treatment with Kuvan: Advise patients that Kuvan may cause low blood Phe levels.  Advise patients that children younger than 7 years treated with Kuvan doses of 20 mg/kg per day are at increased risk for low levels of blood Phe compared with children 7 years and older. Blood Phe levels that are too low for prolonged periods of time may be associated with catabolism and protein breakdown [see Warnings and Precautions (5.3)]. Advise patients that Kuvan is to be used in conjunction with a Phe-restricted diet [see Warnings and Precautions (5.6)]. Advise patients that not all patients with PKU respond to treatment with Kuvan and that response to Kuvan can only be determined by a therapeutic trial [see Warnings and Precautions (5.4, 5.5)]. Advise patients that they must be evaluated for changes in blood Phe after being treated with Kuvan at the recommended dose(s) for age to determine if they are a responder and that  blood Phe levels and dietary Phe intake should be measured frequently during the first month [see Warnings and Precautions (5.4, 5.5)]. Advise patients that they should have frequent blood Phe measurements and nutritional counseling with their physician and other members of the health care team knowledgeable in the management of PKU to ensure maintenance of blood Phe levels in the desirable range [see Warnings and Precautions (5.4)]. Advise patients not to modify their existing dietary Phe intake during the evaluation period in order to get an accurate assessment of the effect of Kuvan on blood Phe levels. Advise patients not to continue treatment with Kuvan if they are determined to be a non-responder during the evaluation period [see Dosage and Administration (2.1)]. Advise patients that reduction of blood Phe levels through dietary control is an important determinant of long-term neurologic outcome in PKU patients. Advise patients that the effect of Kuvan on long-term neurologic function in patients with PKU has not been assessed. Advise patients that Kuvan may cause hypersensitivity reactions including anaphylaxis and rash [see Warnings and Precautions (5.1)]. Advise patients to notify their physician for symptoms of severe gastritis [see Warnings and Precautions (5.2)]. Advise patients that blood Phe levels that are too high for prolonged periods of time can result in neurologic impairment. Advise patients that adequate blood Phe control needs to be maintained to avoid blood Phe levels that are too high or too low.  Advise patients that to ensure maintenance of adequate blood Phe control, close monitoring is recommended and that the dose of Kuvan should be adjusted if necessary.  Advise patients with hepatic impairment and patients who are taking Kuvan in combination with drugs that inhibit folate metabolism, drugs that affect nitric oxide-mediated vasorelaxation, or levodopa that they may require additional clinical monitoring while taking Kuvan[see Warnings and Precautions (5.7, 5.8, 5.9, 5.10)]. Advise patients that Kuvan may cause hyperactivity [see Warnings and Precautions (5.11)].  Advise patients that BioMarin has a product registry for PKU patients to collect data on women who become pregnant while receiving Kuva 治疗罕见病新药Kuvan获欧洲委员会批准上市 近日；欧盟已批准Kuvan(sapropterin dihydrochloride)用于治疗苯丙酮尿症与BH4 缺乏的患者的高苯丙氨酸血症（HPA），之前该药在欧洲儿得罕用药地位。该药为欧洲批准的首个用于苯丙酮尿症与BH4缺乏引发的高苯丙氨酸血症。 二盐酸沙丙蝶呤—首个高苯丙氨酸血症治疗药，二盐酸沙丙蝶呤是首个获准用于治疗四氢生物蝶呤(BH4)缺乏症或苯丙酮尿症(PKU)患者的高苯丙氨酸血症(HPA)的罕用药于在欧洲开始上市。 预计本品将于上半年在欧洲开始上市。 二盐酸沙丙蝶呤最常见的不良反应有头痛、流涕、鼻塞、腹泻、呕吐、咽痛、咳嗽、腹痛、苯丙氨酸血浓度低。这些不良反应的严重程度一般为轻微至中等程度，且为一过性的。 药动学 在健康受试者中进行的研究比较了二盐酸沙丙蝶呤片在溶于水或橙汁以及禁食条件下服用的吸收情况。结果显示，受试者进食高脂或高热量食物后服用溶于水的Kuvan，Cmax增加84％，AUC增加87％。在对Kuvan进行的临床实验中，受试者均于清晨服用溶解后的片剂，而不考虑其饮食情况。该药在PKU患者体内的平均半衰期为6．7h，而在健康受试者中则为3．0—5．3h。 临床研究 有4项临床研究考察了苯丙酮尿症(PKU)患者服用二盐酸沙丙蝶呤的有效性和安全性。第1项研究为对489名8—48岁的PKU患者进行的多中心、开标记、非对照试验。试验前，PKU患者的血清Phe水平高于450μmol／L，且不禁食含Phe的食物，所有受试患者连续8天服用Kuvan[10mg／(kg.d)]；与给药前相比，血清Phe水平降低30％以上视为对该治疗有响应。结果，第8天时，有96名患者的Phe水平达到响应值，响应率为20％。 在经过停药间隔期后，进行了为期6周的第2项研究，该多中心、双盲、安慰剂对照研究选取了第1项研究中对Kuvan治疗有响应的88名患者，并将其随机分为两组：Kuvan[10mg／(kg.d)]组(n=41)和安慰剂组(n=47)。治疗前，两组患的血清Phe水平分别为(843±300)和(888±323)μmol／L；在治疗的第6周，Kuvan组血清Phe水平降为(607±377)μmol／L，而安慰剂组反升至(891±348)tmaol／L，两组平均变化值分别为-239和6μmol／L，有显著性差异。 第3项研究则是前两项研究的扩展试验，为期6周。该试验选取了在第1项研究中对Kuvan治疗有响应并完成第2项研究的8o名患者，对Kuvan的3个剂量进行调整，即前两周的剂量为5mg／(kg.d)，第3、4周为20mg／(kg.d)，第5,6周则为10mg／(kg.d)。每2周测定1次血清Phe值。治疗前，受试患者血清Phe水平为(844±398)μmol／L，而每个剂量组治疗2周后患者血清Phe水平分别为(744±384)、(640±382)和(581±399)μmol／L。 第4项研究为对90名年龄为4-12岁的PKU儿童患者进行的多中心、开标记试验，这些患者均禁食含Phe的食物，且血清Phe水平低于480tmaol／L，连续8天给予Kuvan[20mg／(kg.d)]治疗。与给药前相比，血清Phe水平降低30％以上视为对该治疗有响应。结果，第8天有5O名患者的Phe水平达到响应值，响应率为56％。 http://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=AF38711E-8873-4790-A92D-4D583E23FB89