Droxidopa

1 INDICATIONS AND USAGE Droxidopa capsules indicated for the treatment of orthostatic dizziness, lightheadedness, or the “feeling that you are about to black out” in adult patients with symptomatic neurogenic orthostatic hypotension (nOH) caused by primary autonomic failure (Parkinson's disease [PD], multiple system atrophy, and pure autonomic failure), dopamine beta-hydroxylase deficiency, and non-diabetic autonomic neuropathy. Effectiveness beyond 2 weeks of treatment has not been established. The continued effectiveness of droxidopa capsules should be assessed periodically. Droxidopa capsules are indicated for the treatment of orthostatic dizziness, lightheadedness, or the “feeling that you are about to black out” in adult patients with symptomatic neurogenic orthostatic hypotension (nOH) caused by primary autonomic failure (Parkinson's disease [PD], multiple system atrophy, and pure autonomic failure), dopamine beta-hydroxylase deficiency, and non-diabetic autonomic neuropathy. Effectiveness beyond 2 weeks of treatment has not been established. The continued effectiveness of droxidopa capsules should be assessed periodically.

2 DOSAGE AND ADMINISTRATION • Starting dose is 100 mg three times during the day (2.1) • Titrate by 100 mg three times daily, up to a maximum dose of 600 mg three times daily (2.1) • Take consistently with or without food (2.1) • To reduce the potential for supine hypertension, elevate the head of the bed and give the last dose at least 3 hours prior to bedtime (2.1) • Take droxidopa capsule whole (2.1) 2.1 Dosing Information The recommended starting dose of droxidopa capsules is 100 mg, taken orally three times daily: upon arising in the morning, at midday, and in the late afternoon at least 3 hours prior to bedtime (to reduce the potential for supine hypertension during sleep). Administer droxidopa capsules consistently, either with food or without food. Take droxidopa capsule whole. Titrate to symptomatic response, in increments of 100 mg three times daily every 24 to 48 hours up to a maximum dose of 600 mg three times daily (i.e., a maximum total daily dose of 1,800 mg). Monitor supine blood pressure prior to initiating droxidopa capsules and after increasing the dose. Patients who miss a dose of droxidopa capsules should take their next scheduled dose.

6 ADVERSE REACTIONS The following adverse reactions with droxidopa are included in more detail in the Warnings and Precautions section of the label: • Supine Hypertension [see Warnings and Precautions (5.1) ] • Hyperpyrexia and Confusion [see Warnings and Precautions (5.2) ] • May exacerbate existing ischemic heart disease, arrhythmias, and congestive heart failure [see Warnings and Precautions (5.3) ] The most common adverse reactions (>5% and ≥3% compared to placebo) are headache, dizziness, nausea, and hypertension (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Slate Run Pharmaceuticals, LCC at 1-888-341-9214 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety evaluation of droxidopa is based on two placebo-controlled studies 1 to 2 weeks in duration (Studies 301 and 302), one 8-week placebo-controlled study (Study 306), and two long-term, open-label extension studies (Studies 303 and 304). In the placebo-controlled studies, a total of 485 patients with Parkinson's disease, multiple system atrophy, pure autonomic failure, dopamine beta-hydroxylase deficiency, or non-diabetic autonomic neuropathy were randomized and treated, 245 with droxidopa and 240 with placebo [see Clinical Studies (14) ] . Placebo-Controlled Experience The most commonly observed adverse reactions (those occurring at an incidence of greater than 5% in the droxidopa group and with at least a 3% greater incidence in the droxidopa group than in the placebo group) in droxidopa-treated patients during the three placebo-controlled trials were headache, dizziness, nausea, and hypertension. The most common adverse reactions leading to discontinuation from droxidopa were hypertension or increased blood pressure and nausea. Table 1. Most Common Adverse Reactions Occurring More Frequently in the Droxidopa Group Study 301 and Study 302 (1 to 2 Weeks Randomized Treatment) Study 306 (8 to 10 Weeks Randomized Treatment) Placebo (N=132) n (%) Droxidopa (N=131) n (%) Placebo (N=108) n (%) Droxidopa (N=114) n (%) Headache 4 (3.0) 8 (6.1) 8 (7.4) 15 (13.2) Dizziness 2 (1.5) 5 (3.8) 5 (4.6) 11 (9.6) Nausea 2 (1.5) 2 (1.5) 5 (4.6) 10 (8.8) Hypertension 0 2 (1.5) 1 (0.9) 8 (7.0) Note: n=number of patients. Adverse reactions that were reported in greater than 5% of patients in the droxidopa group and with at least a 3% greater incidence in the droxidopa group than in the placebo group were from Study 306. Long-Term, Open-Label Trials with Droxidopa In the long-term, open-label extension studies, a total of 422 patients, mean age 65 years, were treated with droxidopa for a mean total exposure of approximately one year. The commonly reported adverse events were falls (24%), urinary tract infections (15%), headache (13%), syncope (13%), and dizziness (10%). 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of droxidopa. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiac Disorders : Chest pain Eye Disorders : Blurred vision Gastrointestinal Disorders : Pancreatitis, abdominal pain, vomiting, diarrhea General Disorders and Administration Site Conditions : Fatigue Nervous System Disorders : Cerebrovascular accident Psychiatric Disorders : Psychosis, hallucination, delirium, agitation, memory disorder

12.3 Pharmacokinetics Absorption Peak plasma concentrations (C max ) of droxidopa were reached by 1 to 4 hours post-dose (mean of approximately 2 hours) in healthy volunteers. High-fat meals have a moderate impact on droxidopa exposure with C max and area under the plasma concentration-time curve (AUC) decreasing by 35% and 20%, respectively. The C max was delayed by approximately 2 hours with a high-fat meal. Distribution Pre-clinical studies suggest that droxidopa can cross the blood-brain barrier. Droxidopa exhibits plasma protein binding of 75% at 100 ng/mL and 26% at 10,000 ng/mL. The estimated apparent volume of distribution of droxidopa is about 200 L in humans. Elimination The total clearance of droxidopa after oral administration (CL/F) was approximately 400 mL/hr following administration of a single 300 mg dose. Metabolism The metabolism of droxidopa is mediated by catecholamine pathway and not through the cytochrome P450 system. Droxidopa is initially converted to methoxylated dihydroxyphenylserine (3-OM-DOPS), a major metabolite, by catechol-O-methyltransferase (COMT), to norepinephrine by DOPA decarboxylase (DDC), or to protocatechualdehyde by DOPS aldolase. After oral dosing in humans, plasma norepinephrine levels peak within 3 to 4 hours but are generally very low (less than 1 ng/mL) and variable with no consistent relationship with dose. The contribution of the metabolites of droxidopa other than norepinephrine to its pharmacological effects is not well understood. Excretion The mean elimination half-life of droxidopa is approximately 2.5 hours in humans. The major route of elimination of droxidopa and its metabolites is via the kidneys in both animals and in humans. Studies in animals with radiolabeled drug showed that ~75% of the administered radioactivity was excreted in urine within 24 hours of oral dosing. Specific Populations There are no clinically relevant effects of age, body mass index, or sex on the pharmacokinetics of droxidopa. A population pharmacokinetic analysis suggests that hepatic function, assessed by aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, and total bilirubin, did not influence the exposure to droxidopa. The controlled clinical trials included patients with mild to moderate renal impairment. No dose adjustments are required in patients with mild to moderate renal impairment. Drug Interaction Studies No dedicated drug-drug interaction studies were performed for droxidopa. Patients in the Phase 3 trials with droxidopa received concomitant levodopa/carbidopa, dopamine agonists, MAO-B inhibitors, COMT inhibitors and other medications used to treat Parkinson’s disease. Carbidopa, a peripheral dopa-decarboxylase inhibitor, could prevent the conversion of droxidopa to norepinephrine outside of the central nervous system (CNS). Patients taking droxidopa with L-DOPA/dopa-decarboxylase inhibitor combination drugs had decreased clearance of droxidopa, an increase in overall exposure (AUC) to droxidopa of approximately 100%, and an increase in overall exposure to 3-OM-DOPS of approximately 50%. However, in clinical trials, it was found that the decreased clearance was not associated with a significant need for a different treatment dose or increases in associated adverse events. Dopamine agonists, amantadine derivatives, and MAO-B inhibitors do not appear to affect droxidopa clearance, and no dose adjustments are required.