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美国FDA批准了一项具有里程碑意义的基因疗法，针对罕见病遗传性转甲状腺素蛋白淀粉样变性或hATTR(一种神经病变或神经损伤)的基因疗法。

这也是全球第一例依据诺贝尔奖成果RNA干扰技术开发的药物Onpattro，该药作用机理通过使致病基因“沉默”，进而从根本上治愈该罕见遗传疾病。也是FDA批准的首款小干扰RNA（siRNA）药物。

hATTR影响了全球约50000人，是一种罕见、使人衰弱且常常致命的遗传性疾病。它的主要特征是在体内器官和组织中形成称为淀粉样蛋白的蛋白质纤维异常沉积物，干扰器官和组织的正常功能。这些蛋白质沉积最常发生在周围神经系统中，会导致手臂、腿、手和脚的感觉丧失、疼痛或不能移动。淀粉样蛋白沉积物也会影响心脏、肾脏、眼睛和肠道的功能。目前的治疗方法通常侧重于症状管理，这一领域还有医疗需求亟待满足。

由Alnylam开发的Onpattro是一种靶向转甲状腺素蛋白（transthyretin，TTR）的siRNA疗法，这类药物通过沉默一部分参与致病的RNA起作用。Onpattro是将siRNA包裹在脂质纳米颗粒中，在输注治疗中将药物直接递送至肝脏，干扰异常形式TTR的RNA产生。通过阻止TTR的产生，Onpattro可以帮助减少周围神经中淀粉样沉积物的积累，改善症状，并帮助患者更好地控制病情。该药物曾获得美国FDA授予的突破性疗法认定、优先审评资格、快速通道资格和孤儿药资格。今日它的获批，对患者和医生来说，都具有里程碑的意义。

Onpattro的疗效在临床试验中也得到了证实。在一项包含225名患者的研究中，148名患者被随机分配接受Onpattro输注，每三周一次，共18个月，另外77名患者被随机分配接受相同频率的安慰剂输注。结果显示，与接受安慰剂输注的患者相比，接受Onpattro治疗的患者在多发性神经病变测量方面有更好的结果，包括肌肉力量、感觉（疼痛、体温、麻木）、反射和自主神经症状（血压、心率、消化）。接受Onpattro治疗的患者在行走、营养状况和进行日常活动能力的评估中也有更高的得分。

“这一批准是更广泛的进步浪潮的一部分，这些进展使我们能够通过针对根本病因来治疗疾病，阻止或逆转病情，而不仅仅是减缓其进展或治疗其症状。在hATTR中，疾病会导致神经退化，可能表现为疼痛、虚弱和不能移动，”美国FDA局长Scott Gottlieb博士说：“像RNA抑制剂这样能改变疾病的基因驱动的新技术，有可能为医学界带来转变，使我们能更好地面对、甚至治愈衰弱疾病。我们致力于推进科学原则，以便有效地开发和审查突破性疗法的安全性和疗效，来改变患者的生命。”

“hATTR多发性神经病对治疗方法的需求历来已久。这种独特的靶向疗法为这些患者提供了一种创新的治疗方法，可以直接影响这种疾病的潜在病因。”FDA药物评估和研究中心神经病学产品部主任Billy Dunn博士说。

该药企Alnylam总部位于马萨诸塞州剑桥市，他们是少有的几家具有该独特技术能力研发以RNAi为基因治疗方法的研究机构。公司将以商品药名Patisiran作为临床用药上市。

相对于欧盟监管机构给出的上市条件，FDA的上市条件仅给了Patisiran一个相对精准(狭窄)的临床适应症——治疗罕见神经病变或神经损伤。FDA在宣布批准该药上市的发布会上未提及Onpattro对心脏症状的积极作用。

该公司CEO，John Maraganore先生表示，他们将继续与FDA合作，在临床应用过程中不断扩大该药的临床适应症范围。目前，在美国市场上还没有任何用于治疗该疾病的药物。

FDA局长也表示，该基因药将不是唯一的，未来将有更多、更精准的以基因治疗为“靶标”的药物上市。

FDA越来越强调和重视针对致病病因治疗疾病，特别是遗传性疾病，通过阻断或逆转由于基因突变而引起的病症，而不仅仅减缓疾病的进展或治疗临床症状。

根据临床与经济评论研究院的预测，Patisiran药的平均费用可能在45万美元/年，至少在六位数字内(几十万美元标价)。该评估预测还指出如果药价低于30万美元，可能将无法获益(评估最低折扣价约为34.5万美元 ）。

无论怎样，这将又是一例高价且精准的治疗药，是否患者能自费或医保报销，还是一轮新的争议和谈判。

根据先例，Alnylam公司愿意和医保公司探讨建立一种基于有临床疗效付费报销机制(即不见效果不收钱)，如果该药对某患者无临床疗效，则将全部退款。

从目前情形看，Patisiran可能第一例基于RNAi技术上市的基因药，但肯定不是唯一的。已知该公司自己现在就有三种在研发、基于RNAi的候选药。它们是治疗卟啉症的Givosiran；治疗原发性高草酸尿症罕见肾病的lumasiran；以及治疗血友病的Fitusiran。

该药Onpattro获FDA批准上市后，Alnylam将与安捷伦科技公司合作，后者负责该药生产。据悉，该药最早在周日发货到医院或临床治疗机构为患者提供治疗应用。

Onpattro出对hATTR淀粉样变性罕见病的神经系统症状和生活质量有明确改善，包括对心脏功能有积极作用，常见副作用是外周水肿和输液反应。

临床适应症建议：“Onpattro适用于治疗1期或2期多发性神经疾病的成年患者遗传性转甲状腺素导的淀粉样变性（hATTR淀粉样变性）”。

 

ONPATTRO
(patisiran) Lipid Complex Injection

DESCRIPTION

ONPATTRO contains patisiran, a double-stranded small interfering ribonucleic acid (siRNA), formulated as a lipid complex for delivery to hepatocytes. Patisiran specifically binds to a genetically conserved sequence in the 3’ untranslated region (3’UTR) of mutant and wild-type transthyretin (TTR) messenger RNA (mRNA).

The structural formula is:

A, adenosine; C, cytidine; G, guanosine; U, uridine; Cm, 2’-O-methylcytidine; Um, 2’-O-methyluridine; dT, thymidine

ONPATTRO is supplied as a sterile, preservative-free, white to off-white, opalescent, homogeneous solution for intravenous infusion in a single-dose glass vial. Each 1 mL of solution contains 2 mg of patisiran (equivalent 2.1 mg of patisiran sodium). Each 1 mL also contains 6.2 mg cholesterol USP, 13.0 mg (6Z,9Z,28Z,31Z)-heptatriaconta-6,9,28,31tetraen- 19-yl-4-(dimethylamino) butanoate (DLin-MC3-DMA), 3.3 mg 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1.6 mg α-(3’-{[1,2-di(myristyloxy)propanoxy] carbonylamino}propyl)-ω-methoxy, polyoxyethylene (PEG2000C- DMG), 0.2 mg potassium phosphate monobasic anhydrous NF, 8.8 mg sodium chloride USP, 2.3 mg sodium phosphate dibasic heptahydrate USP, and Water for Injection USP. The pH is ~7.0.

The molecular formula of patisiran sodium is C412 H480 N148 Na40 O290 P40 and the molecular weight is 14304 Da.

Indications & Dosage

INDICATIONS

ONPATTRO is indicated for the treatment of the polyneuropathy of hereditary transthyretin-mediated amyloidosis in adults.

DOSAGE AND ADMINISTRATIONDosing Information

ONPATTRO should be administered by a healthcare professional.

ONPATTRO is administered via intravenous (IV) infusion. Dosing is based on actual body weight.

For patients weighing less than 100 kg, the recommended dosage is 0.3 mg/kg once every 3 weeks.

For patients weighing 100 kg or more, the recommended dosage is 30 mg once every 3 weeks.

Missed Dose

If a dose is missed, administer ONPATTRO as soon as possible.

· If ONPATTRO is administered within 3 days of the missed dose, continue dosing according to the patient’s original schedule.

· If ONPATTRO is administered more than 3 days after the missed dose, continue dosing every 3 weeks thereafter.

Required Premedication

All patients should receive premedication prior to ONPATTRO administration to reduce the risk of infusion-related reactions (IRRs) [see WARNINGS AND PRECAUTIONS]. Each of the following premedications should be given on the day of ONPATTRO infusion at least 60 minutes prior to the start of infusion:

· Intravenous corticosteroid (e.g., dexamethasone 10 mg, or equivalent)

· Oral acetaminophen (500 mg)

· Intravenous H1 blocker (e.g., diphenhydramine 50 mg, or equivalent)

· Intravenous H2 blocker (e.g., ranitidine 50 mg, or equivalent)

For premedications not available or not tolerated intravenously, equivalents may be administered orally.

For patients who are tolerating their ONPATTRO infusions but experiencing adverse reactions related to the corticosteroid premedication, the corticosteroid may be reduced by 2.5 mg increments to a minimum dose of 5 mg of dexamethasone (intravenous), or equivalent.

Some patients may require additional or higher doses of one or more of the premedications to reduce the risk of IRRs [see WARNINGS AND PRECAUTIONS].

Preparation Instructions

ONPATTRO must be filtered and diluted prior to intravenous infusion. The diluted solution for infusion should be prepared by a healthcare professional using aseptic technique as follows:

· Remove ONPATTRO from the refrigerator and allow to warm to room temperature. Do not shake or vortex.

· Inspect visually for particulate matter and discoloration. Do not use if discoloration or foreign particles are present. ONPATTRO is a white to off-white, opalescent, homogeneous solution. A white to off-white coating may be observed on the inner surface of the vial, typically at the liquid-headspace interface. Product quality is not impacted by presence of the white to off-white coating.

· Calculate the required dose of ONPATTRO based on the recommended weight-based dosage [see Dosing Information].

· Withdraw the entire contents of one or more vials into a single sterile syringe.

· Filter ONPATTRO through a sterile 0.45 micron polyethersulfone (PES) syringe filter into a sterile container.

· Withdraw the required volume of filtered ONPATTRO from the sterile container using a sterile syringe.

· Dilute the required volume of filtered ONPATTRO into an infusion bag containing 0.9% Sodium Chloride Injection, USP for a total volume of 200 mL. Use infusion bags that are di(2-ethylhexyl)phthalate-free (DEHPfree).

· Gently invert the bag to mix the solution. Do not shake. Do not mix or dilute with other drugs.

· Discard any unused portion of ONPATTRO.

· ONPATTRO does not contain preservatives. The diluted solution should be administered immediately after preparation. If not used immediately, store in the infusion bag at room temperature (up to 30°C [86°F]) for up to 16 hours (including infusion time). Do not freeze.

Infusion Instructions

· Use a dedicated line with an infusion set containing a 1.2 micron polyethersulfone (PES) in-line infusion filter. Use infusion sets and lines that are DEHP-free.

· Infuse the diluted solution of ONPATTRO intravenously, via an ambulatory infusion pump, over approximately 80 minutes, at an initial infusion rate of approximately 1 mL/min for the first 15 minutes, then increase to approximately 3 mL/min for the remainder of the infusion. The duration of infusion may be extended in the event of an IRR [see WARNINGS AND PRECAUTIONS].

· Administer only through a free-flowing venous access line. Monitor the infusion site for possible infiltration during drug administration. Suspected extravasation should be managed according to local standard practice for non-vesicants.

· Observe the patient during the infusion and, if clinically indicated, following the infusion [see WARNINGS AND PRECAUTIONS].

· After completion of the infusion, flush the intravenous administration set with 0.9% Sodium Chloride Injection, USP to ensure that all ONPATTRO has been administered.

HOW SUPPLIEDDosage Forms And Strengths

Lipid Complex Injection: 10 mg/5 mL (2 mg/mL) white to off-white, opalescent, homogeneous solution in a single-dose vial.

ONPATTRO is a sterile, preservative-free, white to off-white, opalescent, homogeneous solution for intravenous infusion supplied as a 10 mg/5 mL (2 mg/mL) solution in a single-dose glass vial. The vial stopper is not made with natural rubber latex. ONPATTRO is available in cartons containing one single-dose vial each.

The NDC is: 71336-1000-1.

Storage And Handling

Store at 2°C to 8°C (36°F to 46°F). Do not freeze. Discard vial if it has been frozen.

If refrigeration is not available, ONPATTRO can be stored at room temperature up to 25°C (up to 77°F) for up to 14 days.

For storage conditions of ONPATTRO after dilution in the infusion bag, see DOSAGE AND ADMINISTRATION.

Manufactured By: Ajinomoto Althea, Inc. 11040 Roselle Street, San Diego, CA 92121. Revised: Aug 2018

Side Effects & Drug Interactions

SIDE EFFECTS

The following clinically significant adverse reactions are described elsewhere in the labeling:

· Infusion-Related Reactions [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of ONPATTRO cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

A total of 224 patients with polyneuropathy caused by hereditary transthyretin-mediated amyloidosis (hATTR amyloidosis) received ONPATTRO in the placebo-controlled and open-label clinical studies, including 186 patients exposed for at least 1 year, 137 patients exposed for at least 2 years, and 52 patients exposed for at least 3 years. In the placebo-controlled study, 148 patients received ONPATTRO for up to 18 months (mean exposure 17.7 months). Baseline demographic and disease characteristics were generally similar between treatment groups. The median age of study patients was 62 years and 74% were male. Seventy-two percent of study patients were Caucasian, 23% were Asian, 2% were Black, and 2% were reported as other. At baseline, 46% of patients were in Stage 1 of the disease and 53% were in Stage 2. Forty-three percent of patients had Val30Met mutations in the transthyretin gene; the remaining patients had 38 other point mutations. Sixty-two percent of ONPATTRO-treated patients had non-Val30Met mutations, compared to 48% of the placebo-treated patients.

Upper respiratory tract infections and infusion-related reactions were the most common adverse reactions. One patient (0.7%) discontinued ONPATTRO because of an infusion-related reaction.

Table 1 lists the adverse reactions that occurred in at least 5% of patients in the ONPATTRO-treated group and that occurred at least 3% more frequently than in the placebo-treated group in the randomized controlled clinical trial.

Table 1: Adverse Reactions from the Placebo-Controlled Trial that Occurred in at Least 5% of ONPATTRO-treated Patients and at Least 3% More Frequently than in Placebo-treated Patients

Four serious adverse reactions of atrioventricular (AV) heart block (2.7%) occurred in ONPATTRO-treated patients, including 3 cases of complete AV block. No serious adverse reactions of AV block were reported in placebo-treated patients.

Ocular adverse reactions that occurred in 5% or less of ONPATTRO-treated patients in the controlled clinical trial, but in at least 2% of ONPATTRO-treated patients, and more frequently than on placebo, include dry eye (5% vs. 3%), blurred vision (3% vs. 1%), and vitreous floaters (2% vs. 1%).

Extravasation was observed in less than 0.5% of infusions in clinical studies, including cases that were reported as serious. Signs and symptoms included phlebitis or thrombophlebitis, infusion or injection site swelling, dermatitis (subcutaneous inflammation), cellulitis, erythema or injection site redness, burning sensation, or injection site pain.

Immunogenicity

The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. In addition, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to ONPATTRO in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.

Anti-drug antibodies to ONPATTRO were evaluated by measuring antibodies specific to PEG2000-C-DMG, a lipid component exposed on the surface of ONPATTRO. In the placebo-controlled and open-label clinical studies, 7 of 194 (3.6%) patients with hATTR amyloidosis developed anti-drug antibodies during treatment with ONPATTRO. One additional patient had pre-existing anti-drug antibodies. There was no evidence of an effect of anti-drug antibodies on clinical efficacy, safety, or the pharmacokinetic or pharmacodynamic profiles of ONPATTRO. Although these data do not demonstrate an impact of anti-drug antibody development on the efficacy or safety of ONPATTRO in these patients, the available data are too limited to make definitive conclusions.

DRUG INTERACTIONS

No Information Provided

Warnings & Precautions

WARNINGS

Included as part of the "PRECAUTIONS" Section

PRECAUTIONSInfusion-Related Reactions

Infusion-related reactions (IRRs) have been observed in patients treated with ONPATTRO. In clinical studies, all patients received premedication with a corticosteroid, acetaminophen, and antihistamines (H1 and H2 blockers) to reduce the risk of IRRs. In a controlled clinical study, 19% of ONPATTRO-treated patients experienced IRRs, compared to 9% of placebo-treated patients. Among ONPATTRO-treated patients who experienced an IRR, 79% experienced the first IRR within the first 2 infusions. The frequency of IRRs decreased over time. IRRs led to infusion interruption in 5% of patients. IRRs resulted in permanent discontinuation of ONPATTRO in less than 1% of patients in clinical studies. Across clinical studies, the most common symptoms (reported in greater than 2% of patients) of IRRs with ONPATTRO were flushing, back pain, nausea, abdominal pain, dyspnea, and headache [see ADVERSE REACTIONS]. One patient in the ONPATTRO expanded access program had a severe adverse reaction of hypotension and syncope during an ONPATTRO infusion.

Patients should receive premedications on the day of ONPATTRO infusion, at least 60 minutes prior to the start of infusion [see DOSAGE AND ADMINISTRATION]. Monitor patients during the infusion for signs and symptoms of IRRs. If an IRR occurs, consider slowing or interrupting the ONPATTRO infusion and instituting medical management (e.g., corticosteroids or other symptomatic treatment), as clinically indicated. If the infusion is interrupted, consider resuming at a slower infusion rate only if symptoms have resolved. In the case of a serious or life-threatening IRR, the infusion should be discontinued and not resumed.

Some patients who experience IRRs may benefit from a slower infusion rate or additional or higher doses of one or more of the premedications with subsequent infusions to reduce the risk of IRRs [see DOSAGE AND ADMINISTRATION].

Reduced Serum Vitamin A Levels And Recommended Supplementation

ONPATTRO treatment leads to a decrease in serum vitamin A levels. Supplementation at the recommended daily allowance of vitamin A is advised for patients taking ONPATTRO. Higher doses than the recommended daily allowance of vitamin A should not be given to try to achieve normal serum vitamin A levels during treatment with ONPATTRO, as serum vitamin A levels do not reflect the total vitamin A in the body.

Patients should be referred to an ophthalmologist if they develop ocular symptoms suggestive of vitamin A deficiency (e.g., night blindness).

Nonclinical ToxicologyCarcinogenesis, Mutagenesis, Impairment Of FertilityCarcinogenesis

Patisiran-LC was not carcinogenic in TgRasH2 mice when administered at intravenous (IV) doses of 0, 0.5, 2, or 6 mg/kg every two weeks for 26 weeks.

Mutagenesis

Patisiran-LC was negative for genotoxicity in in vitro (bacterial mutagenicity assay, chromosomal aberration assay in human peripheral blood lymphocytes) and in vivo (mouse bone marrow micronucleus) assays.

Impairment Of Fertility

Intravenous (IV) administration of patisiran-LC (0, 0.03, 0.1, or 0.3 mg/kg) or a rodent-specific (pharmacologically active) surrogate (0.1 mg/kg) to male rats every two weeks prior to and throughout mating to untreated females produced no adverse effects on fertility.

Intravenous administration of patisiran-LC (0, 0.15, 0.50, or 1.5 mg/kg) or a rodent-specific (pharmacologically active) surrogate (1.5 mg/kg) to female rats every week for two weeks prior to mating and continuing throughout organogenesis resulted in no adverse effects on fertility or on embryofetal development.

Intravenous administration of patisiran-LC (0, 0.3, 1, or 2 mg/kg) to adult monkeys every three weeks for 39 weeks produced no adverse effects on male reproductive organs or on sperm morphology or count.

Use In Specific PopulationsPregnancyRisk Summary

There are no available data on ONPATTRO use in pregnant women to inform a drug-associated risk of adverse developmental outcomes. ONPATTRO treatment leads to a decrease in serum vitamin A levels, and vitamin A supplementation is advised for patients taking ONPATTRO. Vitamin A is essential for normal embryofetal development; however, excessive levels of vitamin A are associated with adverse developmental effects. The effects on the fetus of a reduction in maternal serum TTR caused by ONPATTRO and of vitamin A supplementation are unknown [see CLINICAL PHARMACOLOGY, WARNINGS AND PRECAUTIONS].

In animal studies, intravenous administration of patisiran lipid complex (patisiran-LC) to pregnant rabbits resulted in developmental toxicity (embryofetal mortality and reduced fetal body weight) at doses that were also associated with maternal toxicity. No adverse developmental effects were observed when patisiran-LC or a rodent-specific (pharmacologically active) surrogate were administered to pregnant rats (see Data).

In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown.

Data

Animal Data

Intravenous administration of patisiran-LC (0, 0.15, 0.50, or 1.5 mg/kg) or a rodent-specific (pharmacologically active) surrogate (1.5 mg/kg) to female rats every week for two weeks prior to mating and continuing throughout organogenesis resulted in no adverse effects on fertility or embryofetal development.

Intravenous administration of patisiran-LC (0, 0.1, 0.3, or 0.6 mg/kg) to pregnant rabbits every week during the period of organogenesis produced no adverse effects on embryofetal development. In a separate study, patisiran-LC (0, 0.3, 1, or 2 mg/kg), administered to pregnant rabbits every week during the period of organogenesis, resulted in embryofetal mortality and reduced fetal body weight at the mid and high doses, which were associated with maternal toxicity.

Intravenous administration of patisiran-LC (0, 0.15, 0.50, or 1.5 mg/kg) or a rodent-specific surrogate (1.5 mg/kg) to pregnant rats every week throughout pregnancy and lactation resulted in no adverse developmental effects on the offspring.

LactationRisk Summary

There is no information regarding the presence of ONPATTRO in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for ONPATTRO and any potential adverse effects on the breastfed infant from ONPATTRO or from the underlying maternal condition.

In lactating rats, patisiran was not detected in milk; however, the lipid components (DLin-MC3-DMA and PEG2000-CDMG) were present in milk.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

No dose adjustment is required in patients ≥65 years old [see CLINICAL PHARMACOLOGY]. A total of 62 patients ≥65 years of age, including 9 patients ≥75 years of age, received ONPATTRO in the placebo-controlled study. No overall differences in safety or effectiveness were observed between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

Hepatic Impairment

No dose adjustment is necessary in patients with mild hepatic impairment (bilirubin ≤1 x ULN and AST >1 x ULN, or bilirubin >1.0 to 1.5 x ULN) [see CLINICAL PHARMACOLOGY]. ONPATTRO has not been studied in patients with moderate or severe hepatic impairment.

Renal Impairment

No dose adjustment is necessary in patients with mild or moderate renal impairment (estimated glomerularfiltration rate [eGFR] ≥30 to <90 mL/min/1.73m2) [see CLINICAL PHARMACOLOGY]. ONPATTRO has not been studied in patients with severe renal impairment or end-stage renal disease.

Overdosage & Contraindications

OVERDOSE

No Information Provided

CONTRAINDICATIONS

None.

Clinical Pharmacology

CLINICAL PHARMACOLOGYMechanism Of Action

Patisiran is a double-stranded siRNA that causes degradation of mutant and wild-type TTR mRNA through RNA interference, which results in a reduction of serum TTR protein and TTR protein deposits in tissues.

Pharmacodynamics

The pharmacodynamic effects of ONPATTRO were evaluated in hATTR amyloidosis patients treated with 0.3 mg/kg ONPATTRO via intravenous infusion once every 3 weeks.

Mean serum TTR was reduced by approximately 80% within 10 to 14 days after a single dose. With repeat dosing every 3 weeks, mean reductions of serum TTR after 9 and 18 months of treatment were 83% and 84%, respectively. The mean maximum reduction of serum TTR over 18 months was 88%. Similar TTR reductions were observed regardless of TTR mutation, sex, age, or race. In a dose-ranging study, greater TTR reduction was maintained over the dosing interval with the recommended dosing regimen of 0.3 mg/kg every 3 weeks compared to 0.3 mg/kg every 4 weeks.

Serum TTR is a carrier of retinol binding protein, which is involved in the transport of vitamin A in the blood. Mean reductions in serum retinol binding protein of 45% and serum vitamin A of 62% were observed over 18 months [see WARNINGS AND PRECAUTIONS].

Pharmacokinetics

Following a single intravenous administration, systemic exposure to patisiran increases in a linear and dose-proportional manner over the range of 0.01 to 0.5 mg/kg. Greater than 95% of patisiran in the circulation is associated with the lipid complex. At the recommended dosing regimen of 0.3 mg/kg every 3 weeks, steady state is reached by 24 weeks of treatment. The estimated mean ± SD steady state peak concentrations (Cmax), trough concentrations (Ctrough), and area under the curve (AUCτ) were 7.15 ± 2.14 μg/mL, 0.021 ± 0.044 μg/mL, and 184 ± 159 μg·h/mL, respectively. The accumulation of AUCτ was 3.2-fold at steady state, compared to the first dose. In the placebo-controlled study, inter-patient variability in patisiran exposure did not result in differences in clinical efficacy (mNIS+7 change from baseline) or safety (adverse events, serious adverse events).

Distribution

Plasma protein binding of ONPATTRO is low, with ≤2.1% binding observed in vitro with human serum albuminand human α1-acid glycoprotein. ONPATTRO distributes primarily to the liver. At the recommended dosing regimen of 0.3 mg/kg every 3 weeks, the mean ± SD steady state volume of distribution of patisiran (Vss) was 0.26 ± 0.20 L/kg.

Elimination

The terminal elimination half-life (mean ± SD) of patisiran is 3.2 ± 1.8 days. Patisiran is mainly cleared through metabolism, and the total body clearance (mean ± SD) at steady state (CLss) is 3.0 ± 2.5 mL/h/kg.

Metabolism

Patisiran is metabolized by nucleases to nucleotides of various lengths.

Excretion

Less than 1% of the administered dose of patisiran is excreted unchanged into urine.

Specific Populations

Age, race (non-Caucasian vs. Caucasian), and sex had no impact on the steady state pharmacokinetics of patisiran or TTR reduction. Population pharmacokinetic and pharmacodynamic analyses indicated no impact of mild or moderate renal impairment (eGFR ≥30 to <90 mL/min/1.73m2) or mild hepatic impairment (bilirubin ≤1 x ULN and AST >1 x ULN, or bilirubin >1.0 to 1.5 x ULN) on patisiran exposure or TTR reduction. ONPATTRO has not been studied in patients with severe renal impairment, end-stage renal disease, moderate or severe hepatic impairment, or in patients with prior liver transplant.

Drug Interaction Studies

No formal clinical drug interaction studies have been performed. The components of ONPATTRO are not inhibitors or inducers of cytochrome P450 enzymes or transporters. Patisiran is not a substrate of cytochrome P450 enzymes. In a population pharmacokinetic analysis, concomitant use of strong or moderate CYP3A inducers and inhibitors did not impact the pharmacokinetic parameters of patisiran. ONPATTRO is not expected to cause drug-drug interactions or to be affected by inhibitors or inducers of cytochrome P450 enzymes.

Clinical Studies

The efficacy of ONPATTRO was demonstrated in a randomized, double-blind, placebo-controlled, multicenter clinical trial in adult patients with polyneuropathy caused by hATTR amyloidosis (NCT 01960348). Patients were randomized in a 2:1 ratio to receive ONPATTRO 0.3 mg/kg (N=148) or placebo (N=77), respectively, via intravenous infusion once every 3 weeks for 18 months. All patients received premedication with a corticosteroid, acetaminophen, and H1 and H2 blockers. Ninety-three percent of ONPATTRO-treated patients and 62% of placebo-treated patients completed 18 months of the assigned treatment.

The primary efficacy endpoint was the change from baseline to Month 18 in the modified NeuropathyImpairment Score +7 (mNIS+7). The mNIS+7 is an objective assessment of neuropathy and comprises the NIS and Modified +7 (+7) composite scores. In the version of the mNIS+7 used in the trial, the NIS objectively measures deficits in cranial nerve function, muscle strength, and reflexes, and the +7 assesses postural blood pressure, quantitative sensory testing, and peripheral nerve electrophysiology. The maximum possible score was 304 points, with higher scores representing a greater severity of disease.

The clinical meaningfulness of effects on the mNIS+7 was assessed by the change from baseline to Month 18 in Norfolk Quality of Life-Diabetic Neuropathy (QoL-DN) total score. The Norfolk QoL-DN scale is a patient-reported assessment that evaluates the subjective experience of neuropathy in the following domains: physical functioning/large fiber neuropathy, activities of daily living, symptoms, small fiber neuropathy, and autonomic neuropathy. The version of the Norfolk QoL-DN that was used in the trial had a total score range from -4 to 136, with higher scores representing greater impairment.

The changes from baseline to Month 18 on both the mNIS+7 and the Norfolk QoL-DN significantly favored ONPATTRO (Table 2, Figure 1 and Figure 3). The distributions of changes in mNIS+7 and Norfolk QoL-DN scores from baseline to Month 18 by percent of patients are shown in Figure 2 and Figure 4, respectively.

The changes from baseline to Month 18 in modified body mass index (mBMI) and gait speed (10-meter walk test) significantly favored ONPATTRO (Table 2).

Table 2: Clinical Efficacy Results from the Placebo-Controlled Study

Figure 1: Change from Baseline in mNIS+7

A decrease in mNIS+7 indicates improvement. ? indicates between-group treatment difference, shown as the LS mean difference (95% CI) for ONPATTRO - placebo.

Figure 2: Histogram of mNIS+7 Change from Baseline at Month 18

mNIS+7 change scores are rounded to the nearest whole number; last available post-baseline scores were used. Categories are mutually exclusive; patients who died before 18 months are summarized in the "Death" category only.

Figure 3: Change from Baseline in Norfolk QoL-DN Score

A decrease in Norfolk QoL-DN score indicates improvement. ? indicates between-group treatment difference, shown as the LS mean difference (95% CI) for ONPATTRO - placebo.

Figure 4: Histogram of Norfolk QoL-DN Change from Baseline at Month 18

Norfolk QoL-DN change scores are rounded to the nearest whole number; last available post-baseline scores were used. Categories are mutually exclusive; patients who died before 18 months are summarized in the "Death" category only.

Patients receiving ONPATTRO experienced similar improvements relative to placebo in mNIS+7 and Norfolk QoL-DN score across all subgroups including age, sex, race, region, NIS score, Val30Met mutation status, and disease stage.

Medication Guide

PATIENT INFORMATIONInfusion-Related Reactions

Inform patients about the signs and symptoms of infusion-related reactions (e.g., flushing, dyspnea, chest pain, rash, increased heart rate, facial edema). Advise patients to contact their healthcare provider immediately if they experience signs and symptoms of infusion-related reactions [see WARNINGS AND PRECAUTIONS].

Recommended Vitamin A Supplementation

Inform patients that ONPATTRO treatment leads to a decrease in vitamin A levels measured in the serum. Instruct patients to take the recommended daily allowance of vitamin A. Advise patients to contact their healthcare provider if they experience ocular symptoms suggestive of vitamin A deficiency (e.g., night blindness) and refer them to an ophthalmologist if they develop these symptoms [see WARNINGS AND PRECAUTIONS].

Pregnancy

Instruct patients that if they are pregnant or plan to become pregnant while taking ONPATTRO they should inform their healthcare provider. Advise female patients of childbearing potential of the potential risk to the fetus [see Use In Specific Populations].

 

 

来源

https://www.rxlist.com/onpattro-drug.htm#medguide