DailyMed Label: Duopa

DailyMed Label: Duopa

2022

DailyMed Prescription

Duopa

Carbidopa and Levodopa

AbbVie Inc.

NDC: 0074-3012

NDC: 0074-3012

DUOPA is a combination of carbidopa, an inhibitor of aromatic amino acid decarboxylation, and levodopa, an aromatic amino acid. Carbidopa is a white, crystalline compound, slightly soluble in water, with a molecular weight of 244.2. It is designated chemically as (2S)-3-(3,4-dihydroxyphenyl)-2-hydrazino-2-methylpropanoic acid monohydrate. Its empirical formula is C 10 H 14 N 2 O 4 •H 2 O, and its structural formula is: The content of carbidopa in DUOPA is expressed in terms of anhydrous carbidopa which has a molecular weight of 226.3. The 4.63 mg/mL of anhydrous carbidopa is equivalent to 5.0 mg/mL of carbidopa. Levodopa is a white, crystalline compound, slightly soluble in water, with a molecular weight of 197.2. It is designated chemically as (2S)-2-Amino-3-(3,4-dihydroxyphenyl) propanoic acid. Its empirical formula is C 9 H 11 NO 4 , and its structural formula is: The inactive ingredients in DUOPA are carmellose sodium and purified water. carbidopa chem structure levodopa chem structure

DUOPA ® is indicated for the treatment of motor fluctuations in patients with advanced Parkinson’s disease. DUOPA is a combination of carbidopa (an aromatic amino acid decarboxylation inhibitor) and levodopa (an aromatic amino acid) indicated for the treatment of motor fluctuations in patients with advanced Parkinson’s disease ( 1 )

The maximum recommended daily dose of DUOPA is 2000 mg of levodopa (i.e., one cassette per day) administered over 16 hours ( 2.1 ) Prior to initiating DUOPA, convert patients from all forms of levodopa to oral immediate-release carbidopa-levodopa tablets (1:4 ratio) ( 2.2 ) Titrate total daily dose based on clinical response for the patient ( 2.2 ) Administer DUOPA into the jejunum through a percutaneous endoscopic gastrostomy with jejunal tube (PEG-J) with the CADD®-Legacy 1400 portable infusion pump ( 2.3 ) DUOPA is administered over a 16-hour infusion period. The daily dose is determined by individualized patient titration and composed of: A Morning Dose A Continuous Dose Extra Doses The maximum recommended daily dose of DUOPA is 2000 mg of the levodopa component (i.e., one cassette per day) administered over 16 hours. At the end of the daily 16-hour infusion, patients will disconnect the pump from the PEG-J and take their night-time dose of oral immediate-release carbidopa-levodopa tablets. Treatment with DUOPA is initiated in 3 steps [see Dosage and Administration ( 2.2 ) ] : Conversion of patients to oral immediate-release carbidopa-levodopa tablets in preparation for DUOPA treatment. Calculation and administration of the DUOPA starting dose (Morning Dose and Continuous Dose) for Day 1. Titration of the dose as needed based on individual clinical response and tolerability. Extra Doses DUOPA has an extra dose function that can be used to manage acute “Off” symptoms that are not controlled by the Morning Dose and the Continuous Dose administered over 16 hours. The extra dose function should be set at 1 mL (20 mg of levodopa) when starting DUOPA. If the amount of the extra dose needs to be adjusted, it is typically done in 0.2 mL increments. The extra dose frequency should be limited to one extra dose every 2 hours. Administration of frequent extra doses may cause or worsen dyskinesias. Once no further adjustments are required to the DUOPA Morning Dose, Continuous Dose, or Extra Dose, this dosing regimen should be administered daily. Over time, additional changes may be necessary based on the patient’s clinical response and tolerability. Prepare for DUOPA Treatment Prior to initiating DUOPA, convert patients from all other forms of levodopa to oral immediate-release carbidopa-levodopa tablets (1:4 ratio). Patients should remain on a stable dose of their concomitant medications taken for the treatment of Parkinson's disease before initiation of DUOPA infusion. Healthcare providers should ensure patients take their oral Parkinson's disease medications the morning of the PEG-J procedure. Determine the DUOPA Starting Dose for Day 1 The steps for determining the initial DUOPA daily dosing (Morning Dose and Continuous Dose) for Day 1 are outlined below. Step 1: Calculate and administer the DUOPA Morning Dose for Day 1 a. Determine the total amount of levodopa (in milligrams) in the first dose of oral immediate-release carbidopa-levodopa that was taken by the patient on the previous day. b. Convert the oral levodopa dose from milligrams to milliliters by multiplying the oral dose by 0.8 and dividing by 20 mg/mL. This calculation will provide the Morning Dose of DUOPA in milliliters. c. Add 3 milliliters to the Morning Dose to fill (prime) the intestinal tube to obtain the Total Morning Dose. d. The Total Morning Dose is usually administered over 10 to 30 minutes. e. Program the pump to deliver the Total Morning Dose. Step 2: Calculate and administer the DUOPA Continuous Dose for Day 1 a. Determine the amount of oral immediate-release levodopa that the patient received from oral immediate-release carbidopa-levodopa doses throughout the previous day (16 waking hours), in milligrams. Do not include the doses of oral immediate-release carbidopa-levodopa taken at night when calculating the levodopa amount. b. Subtract the first oral levodopa dose in milligrams taken by the patient on the previous day (determined in Step 1 (a)) from the total oral levodopa dose in milligrams taken over 16 waking hours (determined in Step 2 (a)). Divide the result by 20 mg/mL. This is the dose of DUOPA administered as a Continuous Dose (in mL) over 16 hours. c. The hourly infusion rate (mL per hour) is obtained by dividing the Continuous Dose by 16 (hours). This value will be programmed into the pump as the continuous rate. d. If persistent or numerous “Off” periods occur during the 16-hour infusion, consider increasing the Continuous Dose or using the Extra Dose function. If dyskinesia or DUOPA-related adverse reactions occur, consider decreasing the Continuous Dose or stopping the infusion until the adverse reactions subside. DUOPA Titration The daily dose of DUOPA can be titrated as needed, based on the patient’s individual clinical response and tolerability after Day 1 of DUOPA treatment and until a stable daily dose is maintained. Adjustments to concomitant Parkinson’s disease medications may be needed. In the controlled trial, the average number of titration days required to establish a stable Morning and Continuous Dose was 5 days. Additional dose adjustments may be necessary over time based on the patient level of activity and disease progression. The recommendations for adjusting the DUOPA Morning and Continuous Doses are provided below. Morning Dose Adjustment If there was an inadequate clinical response within 1 hour of the Morning Dose on the preceding day, adjust the Morning Dose (excluding the 3 mL to fill the tube) as follows: If the Morning Dose on the preceding day was less than or equal to 6 mL, increase the Morning Dose by 1 mL. If the Morning Dose on the preceding day was greater than 6 mL, increase the Morning Dose by 2 mL. If the patient experienced dyskinesias or DUOPA-related adverse reactions within 1 hour of the Morning Dose on the preceding day, decrease the Morning Dose by 1 mL. Continuous Dose Adjustment Consider increasing the Continuous Dose based on the number and volume of Extra Doses of DUOPA (i.e., total amount of levodopa component) that were needed for the previous day and the patient’s clinical response. Consider decreasing the Continuous Dose if the patient experienced troublesome dyskinesia, or other troublesome DUOPA-related adverse reactions on the preceding day: For troublesome adverse reactions lasting for a period of one hour or more, decrease the Continuous Dose by 0.3 mL per hour. For troublesome adverse reactions lasting for two or more periods of one hour or more, decrease the Continuous Dose by 0.6 mL per hour. DUOPA should be used at room temperature. Take one DUOPA cassette out of the refrigerator and out of the carton 20 minutes prior to use; failure to use the product at room temperature may result in the patient not receiving the right amount of medication. DUOPA is delivered as a 16-hour infusion through either a naso-jejunal tube for short-term administration or through a PEG-J for long-term administration. The cassettes are for single-use only and should not be used for longer than 16 hours, even if some drug product remains. An opened cassette should not be re-used. The PEG-J should be disconnected from the pump at the end of the daily 16-hour administration period and flushed with room temperature potable water with a syringe. Long-term administration of DUOPA requires placement of a PEG-J outer transabdominal tube and inner jejunal tube by percutaneous endoscopic gastrostomy. DUOPA is dispensed from medication cassette reservoirs that are specifically designed to be connected to the CADD ® -Legacy 1400 pump. Establishment of the transabdominal port should be performed by a gastroenterologist or other healthcare provider experienced in this procedure. See Table 1  for the recommended tubing sets for PEG-J administration. For short-term, temporary administration of DUOPA prior to PEG-J tube placement, treatment may be initiated by a naso-jejunal tube with observation of the patient’s clinical response. See Table 2 for the recommended tubing sets for naso-jejunal administration. Table 1. Recommended Tubing Sets for Long-Term PEG-J DUOPA Administration Product Name Manufacturer AbbVie PEG 15 and 20 Fr AbbVie J AbbVie Inc. AbbVie Inc. Table 2. Recommended Tubing Sets for Short-Term Naso-Jejunal DUOPA Administration Product Name Manufacturer AbbVie NJ AbbVie Inc. NJFT-10 Wilson-Cook Medical, Inc. Kangaroo™ Naso-Jejunal Feeding Tube Covidien Kangaroo™ Covidien Avoid sudden discontinuation or rapid dose reduction in patients taking DUOPA. If patients need to discontinue DUOPA, the dose should be tapered or patients should be switched to oral immediate-release carbidopa-levodopa tablets [see Warnings and Precautions ( 5.7 ) ] . When using a PEG-J tube, DUOPA can be discontinued by withdrawing the tube and letting the stoma heal. The removal of the tube should only be performed by a qualified healthcare provider.

Enteral suspension: 4.63 mg carbidopa and 20 mg levodopa per mL in a single-use cassette. Each cassette contains approximately 100 mL of suspension. Enteral Suspension: 4.63 mg carbidopa and 20 mg levodopa per mL ( 3 )

DUOPA is contraindicated in patients who are currently taking a nonselective monoamine oxidase (MAO) inhibitor (e.g., phenelzine and tranylcypromine) or have recently (within 2 weeks) taken a nonselective MAO inhibitor. Hypertension can occur if these drugs are used concurrently [see Drug Interactions ( 7.1 and 7.2 )] . DUOPA is contraindicated in patients taking nonselective monoamine oxidase (MAO) inhibitors ( 4 )

Gastrointestinal procedure-related complications may result in serious outcomes, such as need for surgery or death ( 5.1 ) May cause falling asleep during activities of daily living ( 5.2 ) Monitor patients for orthostatic hypotension, especially after starting DUOPA or increasing the dose ( 5.3 ) Hallucinations/Psychosis/Confusion: May respond to dose reduction in levodopa ( 5.4 ) Impulse Control Disorders: Consider dose reductions or stopping DUOPA ( 5.5 ) Monitor patients for depression and suicidality ( 5.6 ) Avoid sudden discontinuation or rapid dose reduction to reduce the risk of withdrawal-emergent hyperpyrexia and confusion ( 5.7 ) May cause or exacerbate dyskinesia: Consider dose reduction ( 5.8 ) Monitor patients for signs and symptoms of peripheral neuropathy ( 5.9 ) Because DUOPA is administered using a PEG-J or naso-jejunal tube, gastrointestinal complications can occur. These complications include abscess, bezoar, ileus, implant site erosion/ulcer, intestinal hemorrhage, intestinal ischemia, intestinal obstruction, intestinal perforation, intussusception, pancreatitis, peritonitis, pneumonia (including aspiration pneumonia), pneumoperitoneum, post-operative wound infection, and sepsis. These complications may result in serious outcomes, such as the need for surgery or death. Instruct patients to notify their healthcare provider immediately if they experience abdominal pain, prolonged constipation, nausea, vomiting, fever, or melanotic stool [see Patient Counseling Information ( 17 ) ] . Patients treated with levodopa, a component of DUOPA, have reported falling asleep while engaged in activities of daily living, including the operation of motor vehicles, which sometimes resulted in accidents. Although many of these patients reported somnolence while on levodopa, some perceived that they had no warning signs (sleep attack), such as excessive drowsiness, and believed that they were alert immediately prior to the event. Some of these events have been reported more than one year after initiation of treatment. Falling asleep while engaged in activities of daily living usually occurs in patients experiencing preexisting somnolence, although patients may not give such a history. For this reason, prescribers should reassess patients for drowsiness or sleepiness in DUOPA-treated patients, especially since some of the events occur well after the start of treatment. Prescribers should be aware that patients may not acknowledge drowsiness or sleepiness until directly questioned about drowsiness or sleepiness during specific activities. Patients who have already experienced somnolence or an episode of sudden sleep onset should not participate in these activities while taking DUOPA. Before initiating treatment with DUOPA, advise patients about the potential to develop drowsiness and specifically ask about factors that may increase the risk for somnolence with DUOPA such as the use of concomitant sedating medications or the presence of sleep disorders. Consider discontinuing DUOPA in patients who report significant daytime sleepiness or episodes of falling asleep during activities that require active participation (e.g., conversations, eating). If DUOPA is continued, they should be advised to avoid driving and other potentially dangerous activities that might result in harm if the patient becomes somnolent. DUOPA-treated patients were more likely to experience a decline in orthostatic blood pressure than patients treated with oral immediate-release carbidopa-levodopa in the controlled clinical study. Orthostatic systolic hypotension (≥30 mm Hg decrease) occurred in 73% of DUOPA-treated patients compared to 68% of patients treated with oral immediate-release carbidopa-levodopa in the controlled clinical study. Orthostatic diastolic hypotension (≥20 mm Hg decrease) occurred in 70% of DUOPA-treated patients compared to 62% of patients treated with oral immediate-release carbidopa-levodopa. Inform patients about the risk for hypotension and syncope. Monitor patients for orthostatic hypotension, especially after starting DUOPA or increasing the dose. There is an increased risk for hallucinations and psychosis in patients taking DUOPA. In the controlled clinical trial, hallucinations occurred in 5% of DUOPA-treated patients compared to 3% of patients treated with oral immediate-release carbidopa-levodopa. Confusion occurred in 8% of DUOPA-treated patients compared to 3% of patients treated with oral immediate-release carbidopa-levodopa, and psychotic disorder occurred in 5% of DUOPA-treated patients compared to 3% of patients treated with oral immediate-release carbidopa-levodopa. Hallucinations associated with levodopa may present shortly after the initiation of therapy and may be responsive to dose reduction in levodopa. Confusion, insomnia, and excessive dreaming may accompany hallucinations. Abnormal thinking and behavior may present with one or more symptoms, including paranoid ideation, delusions, hallucinations, confusion, psychosis, disorientation, aggressive behavior, agitation, and delirium. Because of the risk of exacerbating psychosis, patients with a major psychotic disorder should not be treated with DUOPA. In addition, medications that antagonize the effects of dopamine used to treat psychosis may exacerbate the symptoms of Parkinson’s disease and may decrease the effectiveness of DUOPA [see Drug Interactions ( 7.3 ) ] . Patients may experience intense urges to gamble, increased sexual urges, intense urges to spend money, binge or compulsive eating, and/or other intense urges, and the inability to control these urges while taking one or more of the medications, including DUOPA, that increase central dopaminergic tone and that are generally used for the treatment of Parkinson’s disease. In some cases, although not all, these urges were reported to have stopped when the dose was reduced or the medication was discontinued. Because patients may not recognize these behaviors as abnormal, it is important for prescribers to ask patients or their caregivers specifically about the development of new or increased gambling urges, sexual urges, uncontrolled spending, binge or compulsive eating, or other urges while being treated with DUOPA. Consider reducing the dose or discontinuing DUOPA if a patient develops such urges. In the controlled clinical trial, 11% of DUOPA-treated patients developed depression compared to 3% of oral immediate-release carbidopa-levodopa-treated patients. Monitor patients for the development of depression and concomitant suicidal tendencies. A symptom complex that resembles neuroleptic malignant syndrome (characterized by elevated temperature, muscular rigidity, altered consciousness, and autonomic instability), with no other obvious etiology, has been reported in association with rapid dose reduction, withdrawal of, or changes in dopaminergic therapy. Avoid sudden discontinuation or rapid dose reduction in patients taking DUOPA. If DUOPA is discontinued, the dose should be tapered to reduce the risk of hyperpyrexia and confusion [see Dosage and Administration ( 2.4 ) ] . DUOPA may cause or exacerbate dyskinesias. In the controlled clinical trial, dyskinesia occurred in 14% of DUOPA-treated patients compared to 12% of patients treated with oral immediate-release carbidopa-levodopa. The occurrence of dyskinesias may require a dosage reduction of DUOPA or other medications used to treat Parkinson’s disease. In clinical studies, 19 of 412 (5%) patients treated with DUOPA developed a generalized polyneuropathy. The onset of neuropathy could be determined in 13 of 19 patients. Most cases (12/19) were classified as subacute or chronic in onset. The neuropathy was most often characterized as sensory or sensorimotor. Electrodiagnostic testing performed in 16 patients was most often (15/16) consistent with an axonal polyneuropathy, and one patient was classified as having a demyelinating neuropathy. There was insufficient information to determine the potential role of vitamin deficiencies in the etiology of neuropathy associated with DUOPA. Patients should have clinical assessments for the signs and symptoms of peripheral neuropathy before starting DUOPA. Monitor patients periodically for signs of neuropathy after starting DUOPA, especially in patients with pre-existing neuropathy and in patients taking medications or those who have medical conditions that are also associated with neuropathy. In clinical studies, myocardial infarction and arrhythmia were reported in patients taking carbidopa-levodopa. Ask patients about symptoms of ischemic heart disease and arrhythmia, especially those with a history of myocardial infarction or cardiac arrhythmias. DUOPA may increase the risk for elevated (above the upper limit of normal for the reference range) blood urea nitrogen (BUN) and creatine phosphokinase (CPK). In the controlled clinical trial, the shift from a low or normal value at baseline to an increased BUN value was greater for DUOPA-treated patients (13%) than for patients treated with oral immediate-release carbidopa-levodopa (4%). The shift from a low or normal value at baseline to an increased CPK value was greater for DUOPA-treated patients (17%) than for patients treated with oral immediate-release carbidopa-levodopa (7%). The incidence of patients with a markedly increased BUN (≥10 mmol/L; ≥28 mg/dL) was greater for patients treated with DUOPA (11%) than that for patients treated with oral immediate-release carbidopa-levodopa (0%). The incidence of patients with an increased CPK (>3 times the upper limit of normal) was greater for patients treated with DUOPA (9%) than that for patients treated with oral immediate-release carbidopa-levodopa (0%). Patients taking levodopa or carbidopa-levodopa may have increased levels of catecholamines and their metabolites in plasma and urine giving false positive results suggesting the diagnosis of pheochromocytoma in patients on levodopa and carbidopa-levodopa. Carbidopa-levodopa may cause increased intraocular pressure in patients with glaucoma. Monitor intraocular pressure in patients with glaucoma after starting DUOPA.

The following serious adverse reactions are discussed below and elsewhere in labeling:

Selective MAO-B inhibitors: May cause orthostatic hypotension ( 7.1 ) Antihypertensive drugs: May cause symptomatic postural hypotension. Dosage adjustment of the antihypertensive drug may be needed ( 7.2 ) Dopamine D2 receptor antagonists, isoniazid, iron salts, and high-protein diet may reduce the effectiveness of DUOPA ( 7.3 , 7.4 , 7.5 ) The use of nonselective MAO inhibitors with DUOPA is contraindicated [see Contraindications ( 4 ) ] . Discontinue use of any nonselective MAO inhibitors at least two weeks prior to initiating DUOPA. The use of selective MAO-B inhibitors (e.g., rasagiline and selegiline) with DUOPA may be associated with orthostatic hypotension. Monitor patients who are taking these drugs. The concurrent use of DUOPA with antihypertensive medications can cause symptomatic postural hypotension. A dose reduction of the antihypertensive medication may be needed after starting or increasing the dose of DUOPA. Dopamine D2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone, metoclopramide, papaverine) and isoniazid may reduce the effectiveness of levodopa. Monitor patients for worsening Parkinson’s symptoms. Iron salts or multi-vitamins containing iron salts can form chelates with levodopa, carbidopa, and can cause a reduction in the bioavailability of DUOPA. If iron salts or multi-vitamins containing iron salts are co-administered with DUOPA, monitor patients for worsening Parkinson’s symptoms. Because levodopa competes with certain amino acids for transport across the gut wall, the absorption of levodopa may be decreased in patients on a high-protein diet. Advise patients that a high-protein diet may reduce the effectiveness of DUOPA.

Pregnancy: Based on animal data, may cause fetal harm ( 8.1 ) Risk Summary There are no adequate data on the developmental risk associated with the use of DUOPA in pregnant women. In animal studies, carbidopa-levodopa has been shown to be developmentally toxic (including teratogenic effects) at clinically relevant doses (see Data) . The estimated background risk of major birth defects and miscarriage in the indicated population is unknown. 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. Data Animal Data When administered to pregnant rabbits throughout organogenesis, carbidopa-levodopa caused both visceral and skeletal malformations in fetuses at all doses and ratios of carbidopa-levodopa tested. No teratogenic effects were observed when carbidopa-levodopa was administered to pregnant mice throughout organogenesis. There was a decrease in the number of live pups delivered by rats receiving carbidopa-levodopa during organogenesis. Risk Summary Levodopa has been detected in human milk after administration of carbidopa-levodopa. There are no data on the presence of carbidopa in human milk, the effects of levodopa or carbidopa on the breastfed infant, or the effects on milk production. However, inhibition of lactation may occur because levodopa decreases secretion of prolactin in humans. Carbidopa is excreted in rat milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for DUOPA and any potential adverse effects on the breastfed infant from DUOPA or from the underlying maternal condition. Safety and effectiveness in pediatric patients have not been established. In the controlled clinical trial, 49% of patients were 65 years and older, and 8% were 75 years and older. In patients 65 years and older, there was an increased risk for elevation of BUN and CPK (above the upper limit of the normal reference range for these laboratory analytes) during treatment with DUOPA compared to the risk for patients less than 65 years.

Single-use cassettes containing 4.63 mg carbidopa (as 5 mg of the monohydrate) and 20 mg levodopa per mL of enteral suspension. Each cassette contains approximately 100 mL of suspension. Carton of 7 DUOPA cassettes: NDC 0074-3012-07 Store in freezer at -20 o C (-4 o F). Thaw in refrigerator at 2 o C to 8 o C (36 o F to 46 o F) prior to dispensing. Cassettes should be protected from light and kept in the carton prior to use. Thawing instructions for pharmacies Assign a 15 week “Use By” date based on the time the cartons are put into the refrigerator to thaw. Fully thaw DUOPA in the refrigerator prior to dispensing. In order to ensure controlled thawing of DUOPA, take the cartons containing the seven individual cassettes out of the transport box and separate the cartons from each other. Thawing may take up to 96 hours when the cartons are taken out of the transport box. Once the product has thawed, the individual cartons may be packed in a closer configuration within the refrigerator.

Figure 1. Plasma Concentrations (mean ± standard deviation) versus Time Profile of Levodopa with DUOPA (levodopa, 1580 ± 403 mg; carbidopa, 366 ± 92 mg) 16-Hour Infusion Carbidopa When levodopa is administered orally, it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system. Carbidopa inhibits the decarboxylation of peripheral levodopa, making more levodopa available for delivery to the brain. Levodopa Levodopa is the metabolic precursor of dopamine, does cross the blood-brain barrier, and presumably is converted to dopamine in the brain. This is thought to be the mechanism whereby levodopa treats the symptoms of Parkinson's disease. Because its decarboxylase inhibiting activity is limited to extracerebral tissues, administration of carbidopa with levodopa makes more levodopa available to the brain. The addition of carbidopa to levodopa reduces the peripheral effects (e.g., nausea and vomiting) due to decarboxylation of levodopa; however, carbidopa does not decrease the adverse reactions due to the central effects of levodopa. The pharmacokinetics of carbidopa and levodopa with 16-hour intrajejunal infusion of DUOPA was evaluated in 18 patients with advanced Parkinson's disease who had been on DUOPA therapy for 30 days or longer. Patients remained on their individualized DUOPA doses. The plasma concentrations versus time profile for levodopa with DUOPA 16-hour intrajejunal infusion is presented in Figure 1 . Figure 1. Plasma Concentrations (mean ± standard deviation) versus Time Profile of Levodopa with DUOPA (levodopa, 1580 ± 403 mg; carbidopa, 366 ± 92 mg) 16-Hour Infusion Absorption and Bioavailability Following initiation of the 16-hour intrajejunal infusion of DUOPA, peak plasma levels of levodopa is reached at 2.5 hours. The absorption of levodopa may be decreased in patients on a high-protein diet because levodopa competes with certain amino acids for transport across the gut wall. The gastric emptying rate does not influence the absorption of DUOPA since it is administered by continuous intestinal infusion. In a cross-study population pharmacokinetic analysis, DUOPA had comparable bioavailability to the oral immediate-release carbidopa-levodopa (25/100 mg) tablets (over-encapsulated tablets). The estimated bioavailability for levodopa from DUOPA relative to oral immediate-release carbidopa-levodopa tablets was 97% (95% confidence interval; 95% to 98%). In the controlled clinical trial, the intra-subject variability in carbidopa and levodopa plasma concentrations were lower for patients treated with DUOPA (N=33, 25% and 21%, respectively) than in patients treated with oral immediate-release carbidopa-levodopa (25/100 mg) tablets (N=28, 39% and 67%, respectively). Distribution Carbidopa is approximately 36% bound to plasma proteins. Levodopa is approximately 10-30% bound to plasma proteins. Metabolism and Elimination Carbidopa Carbidopa is metabolized to two main metabolites (α-methyl-3-methoxy-4-hydroxyphenylpropionic acid and α-methyl-3,4-dihydroxyphenylpropionic acid). These 2 metabolites are primarily eliminated in the urine unchanged or as glucuronide conjugates. Unchanged carbidopa accounts for 30% of the total urinary excretion. The elimination half-life of carbidopa is approximately 2 hours. Levodopa Levodopa is mainly eliminated via metabolism by the aromatic amino acid decarboxylase (AAAD) and the catechol-O-methyl-transferase (COMT) enzymes. Other routes of metabolism are transamination and oxidation. The decarboxylation of levodopa to dopamine by AAAD is the major enzymatic pathway when no enzyme inhibitor is co-administered. O-methylation of levodopa by COMT forms 3-O-methyldopa. When administered with carbidopa, the elimination half-life of levodopa is approximately 1.5 hours (see Figure 1 ). Drug Interaction Studies COMT Inhibitors Systemic exposure of levodopa is expected to increase in the presence of entacapone.

Carcinogenesis In rat, oral administration of carbidopa-levodopa for two years resulted in no evidence of carcinogenicity. DUOPA contains hydrazine, a degradation product of carbidopa. In published studies, hydrazine has been demonstrated to be carcinogenic in multiple animal species. Increases in liver (adenoma, carcinoma) and lung (adenoma, adenocarcinoma) tumors have been reported with oral administration of hydrazine in mouse, rat, and hamster. Mutagenesis Carbidopa was positive in the in vitro Ames test, in the presence and absence of metabolic activation, and the in vitro mouse lymphoma tk assay in the absence of metabolic activation but was negative in the in vivo mouse micronucleus assay. In published studies, hydrazine was reported to be positive in in vitro genotoxicity (Ames, chromosomal aberration in mammalian cells, and mouse lymphoma tk ) assays and in the in vivo mouse micronucleus assay. Impairment of Fertility In reproduction studies, no effects on fertility were observed in rats receiving carbidopa-levodopa.

The efficacy of DUOPA was established in a randomized, double-blind, double-dummy, active-controlled, parallel group, 12-week study (Study 1) in patients with advanced Parkinson's disease who were levodopa-responsive and had persistent motor fluctuations while on treatment with oral immediate-release carbidopa-levodopa and other Parkinson's disease medications. Patients were eligible for participation in the studies if they were experiencing 3 hours or more of “Off” time on their current Parkinson's disease drug treatment and they demonstrated a clear responsiveness to treatment with levodopa. Seventy-one (71) patients enrolled in the study and 66 patients completed the treatment (3 patients discontinued treatment because of adverse reactions, 1 patient for lack of effect, and 1 patient for non-compliance). Patients enrolled in this study had a mean age of 64 years and disease duration of 11 years. Most patients (89%) were taking at least one concomitant medication for Parkinson’s disease (e.g., dopaminergic agonist, COMT-inhibitor, MAO-B inhibitor) in addition to oral immediate-release carbidopa-levodopa. Thirty nine percent of patients were taking two or more of such concomitant medications. Patients were randomized to either DUOPA and placebo capsules or placebo suspension and oral immediate-release carbidopa-levodopa 25/100 mg capsules. Patients in both treatment arms had a PEG-J device placement. DUOPA or placebo-suspension was infused over 16 hours daily through a PEG-J tube via the CADD ® -Legacy 1400 model ambulatory infusion pump. The mean daily levodopa dose was 1117 mg/day in the DUOPA group and 1351 mg/day in the oral immediate-release carbidopa-levodopa group. The clinical outcome measure in Study 1 was the mean change from baseline to Week 12 in the total daily mean “Off” time, based on a Parkinson's disease diary. The "Off" time was normalized to a 16-hour awake period, based on a typical person's waking day and the daily infusion duration of 16 hours. The mean score decrease (i.e., improvement) in “Off” time from baseline to Week 12 for DUOPA was significantly greater (p=0.0015) than for oral immediate-release carbidopa-levodopa. Additionally, the mean score increase (i.e., improvement) in “On” time without troublesome dyskinesia from baseline to Week 12 was significantly greater (p=0.0059) for DUOPA than for oral immediate-release carbidopa-levodopa. The treatment difference (DUOPA – oral immediate release carbidopa-levodopa) for decrease in “Off” time was approximately 1.9 hours and the treatment difference for the increase in “On” time without troublesome dyskinesia was approximately 1.9 hours. Results of Study 1 are shown in Table 4 . Table 4. Change from Baseline to Week 12 in "Off" Time and in "On" Time Without Troublesome Dyskinesia in Patients with Advanced Parkinson’s Disease Treatment Group Baseline (hours) LS Mean Change from Baseline at Week 12 (hours) "Off" time   Oral immediate-release carbidopa-levodopa 6.9 -2.1    DUOPA 6.3 -4.0* "On" time without troublesome dyskinesia   Oral immediate-release carbidopa-levodopa 8.0 2.2    DUOPA 8.7 4.1* LS Mean Change from Baseline based on Analysis of Covariance (ANCOVA). *=Statistically Significant. Figure 2 shows results over time according to treatment for the efficacy variable (change from baseline in “Off” time) that served as the clinical outcome measure at the end of the trial at 12 weeks. Figure 2. Change in “Off” Time Over 12 Weeks. Figure 2. Change in “Off” Time Over 12 Weeks.

NDC 0074-3012-07 Duopa ® carbidopa and levodopa enteral suspension 4.63 mg / 20 mg per mL 7 Cassettes (100 mL each) THIS PACKAGE NOT INTENDED FOR HOUSEHOLDS WITH YOUNG CHILDREN Each mL contains 5 mg of carbidopa monohydrate (equivalent to 4.63 mg of carbidopa anhydrous) and 20 mg of levodopa. Pharmacist: Store frozen. Thaw in refrigerator prior to dispensing. See package insert for full prescribing information. Store in the refrigerator between 36 ° -46 ° F (2 ° -8 ° C). Protect from light. Store cassettes in the carton until use. Rx only abbvie NDC 0074-3012-07 Duopa® carbidopa and levodopa enteral suspension 4.63 mg / 20 mg per mL 7 Cassettes (100 mL each) THIS PACKAGE NOT INTENDED FOR HOUSEHOLDS WITH YOUNG CHILDREN Each mL contains 5 mg of carbidopa monohydrate (equivalent to 4.63 mg of carbidopa anhydrous) and 20 mg of levodopa. Pharmacist: Store frozen. Thaw in refrigerator prior to dispensing. See package insert for full prescribing information. Store in the refrigerator between 36°-46°F (2°-8°C). Protect from light. Store cassettes in the carton until use. Rx only abbvie