Naldemedine

12.1 Mechanism of Action Naldemedine is an opioid antagonist with binding affinities for mu-, delta-, and kappa-opioid receptors. Naldemedine functions as a peripherally-acting mu-opioid receptor antagonist in tissues such as the gastrointestinal tract, thereby decreasing the constipating effects of opioids. Naldemedine is a derivative of naltrexone to which a side chain has been added that increases the molecular weight and the polar surface area, thereby reducing its ability to cross the blood-brain barrier (BBB). Naldemedine is also a substrate of the P-glycoprotein (P-gp) efflux transporter. Based on these properties, the CNS penetration of naldemedine is expected to be negligible at the recommended dose levels, limiting the potential for interference with centrally-mediated opioid analgesia.

1 INDICATIONS AND USAGE SYMPROIC is indicated for the treatment of opioid-induced constipation (OIC) in adult patients with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation. SYMPROIC is an opioid antagonist indicated for the treatment of opioid-induced constipation (OIC) in adult patients with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation ( 1 )

2 DOSAGE AND ADMINISTRATION Administration ( 2.1 ) : Alteration of analgesic dosing regimen prior to initiating SYMPROIC is not required Patients receiving opioids for less than 4 weeks may be less responsive to SYMPROIC Discontinue SYMPROIC if treatment with the opioid pain medication is also discontinued Dosage ( 2.2 ) : In adults, the recommended dosage is 0.2 mg once daily with or without food 2.1 Administration Alteration of analgesic dosing regimen prior to initiating SYMPROIC is not required. Patients receiving opioids for less than 4 weeks may be less responsive to SYMPROIC [see Clinical Studies (14) ] . Discontinue SYMPROIC if treatment with the opioid pain medication is also discontinued. 2.2 Adult Dosage The recommended dosage of SYMPROIC is 0.2 mg orally once daily with or without food.

6 ADVERSE REACTIONS Serious and important adverse reactions described elsewhere in labeling include: Gastrointestinal perforation [see Warnings and Precautions (5.1) ] Opioid withdrawal [see Warnings and Precautions (5.2) ] Most common adverse reactions (≥2%) are: abdominal pain, diarrhea, nausea and gastroenteritis ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact BioDelivery Sciences International, Inc. at 1-800-469-0261 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 practice. The data described below reflect exposure to SYMPROIC in 1163 patients in clinical trials, including 487 patients with exposures greater than six months and 203 patients with exposures of 12 months. The following safety data are derived from three double-blind, placebo-controlled trials in patients with OIC and chronic non-cancer pain: two 12-week studies (Studies 1 and 2) and one 52-week study (Study 3) [see Clinical Studies (14) ]. In Studies 1 and 2, patients on laxatives were required to discontinue their use prior to study enrollment. All patients were restricted to bisacodyl rescue treatment during the study. In Study 3, approximately 60% of patients in both treatment groups were on a laxative regimen at baseline; patients were allowed to continue using their laxative regimen throughout the study duration. The safety profile of SYMPROIC relative to placebo was similar regardless of laxative use. Tables 1 and 2 list common adverse reactions occurring in at least 2% of patients receiving SYMPROIC and at an incidence greater than placebo. Table 1 shows pooled 12-week data from Studies 1 and 2. Table 2 shows 12-week data from Study 3. Table 1: Common Adverse Reactions Adverse reactions occurring in at least 2% of patients receiving SYMPROIC and at an incidence greater than placebo in Patients with OIC and Chronic Non-Cancer Pain (12-week data from Studies 1 and 2) Adverse Reaction SYMPROIC 0.2 mg once daily N=542 Placebo N=546 Abdominal pain Abdominal pain includes abdominal discomfort, abdominal pain, abdominal pain lower, abdominal pain upper, gastrointestinal pain. 8% 2% Diarrhea 7% 2% Nausea 4% 2% Gastroenteritis 2% 1% Table 2: Common Adverse Reactions Adverse reactions occurring in at least 2% of patients receiving SYMPROIC and at an incidence greater than placebo in Patients with OIC and Chronic Non-Cancer Pain (12-week data from Study 3) Adverse Reaction SYMPROIC 0.2 mg once daily N=621 Placebo N=619 Abdominal pain Abdominal pain includes abdominal discomfort, abdominal pain, abdominal pain lower, abdominal pain upper. 11% 5% Diarrhea 7% 3% Nausea 6% 5% Vomiting 3% 2% Gastroenteritis 3% 1% Adverse reactions up to 12 months in Study 3 are similar to those listed in Tables 1 and 2 (diarrhea: 11% vs. 5%, abdominal pain: 8% vs. 3%, and nausea: 8% vs. 6% for SYMPROIC and placebo, respectively). Opioid Withdrawal In Studies 1, 2 and 3, adverse reactions consistent with opioid withdrawal were based on investigator assessment and adjudicated based upon the occurrence of at least 3 adverse reactions potentially related to opioid withdrawal with onset of a constellation of those symptoms occurring on the same day or within one day of each other. Adverse reactions of possible opioid withdrawal could include non-gastrointestinal (GI) symptoms (e.g., hyperhidrosis, hot flush or flushing, chills, tremor, tachycardia, anxiety, agitation, yawning, rhinorrhea, increased lacrimation, sneezing, feeling cold, and pyrexia), GI symptoms (e.g., vomiting, diarrhea, or abdominal pain), or both GI and non-GI symptoms. In pooled Studies 1 and 2, the incidence of adverse reactions of opioid withdrawal was 1% (8/542) for SYMPROIC and 1% (3/546) for placebo. In Study 3 (52-week data), the incidence was 3% (20/621) for SYMPROIC and 1% (9/619) for placebo. Most SYMPROIC treated subjects experienced nearly equal incidence of GI only or both GI and non-GI symptoms. Less Common Adverse Reactions: Two patients developed symptoms of hypersensitivity following a single dose of SYMPROIC. One patient reported bronchospasm and another rash. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of SYMPROIC. Because reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate the frequency or establish a causal relationship to drug exposure. Gastrointestinal disorders : Gastrointestinal perforation [see Warnings and Precautions (5.1) ].

7 DRUG INTERACTIONS Table 3 includes drugs with clinically important drug interactions with SYMPROIC and instructions for preventing or managing the interaction. Table 3: Clinically Relevant Interactions Affecting Naldemedine When Co-Administered with Other Drugs Strong CYP3A Inducers (e.g., rifampin, carbamazepine, phenytoin, St. John's Wort) Clinical Impact Significant decrease in plasma naldemedine concentrations, which may reduce efficacy [see Clinical Pharmacology (12.3) ] Intervention Avoid use of SYMPROIC with strong CYP3A inducers. Other Opioid Antagonists Clinical Impact Potential for additive effect of opioid receptor antagonism and increased risk of opioid withdrawal. Intervention Avoid use of SYMPROIC with another opioid antagonist. Moderate (e.g., fluconazole, atazanavir, aprepitant, diltiazem, erythromycin) and Strong (e.g., itraconazole, ketoconazole, clarithromycin, ritonavir, saquinavir) CYP3A Inhibitors Clinical Impact Increase in plasma naldemedine concentrations [see Clinical Pharmacology (12.3) ] Intervention Monitor for potential naldemedine-related adverse reactions [see Adverse Reactions (6.1) ] . P-glycoprotein (P-gp) Inhibitors (e.g., amiodarone, captopril, cyclosporine, quercetin, quinidine, verapamil) Clinical Impact Increase in plasma naldemedine concentrations [see Clinical Pharmacology (12.3) ] Intervention Monitor for potential naldemedine-related adverse reactions [see Adverse Reactions (6.1) ] . Strong CYP3A inducers (e.g., rifampin) : Decreased naldemedine concentrations; avoid concomitant use ( 7 ) Other opioid antagonists : Potential for additive effect and increased risk of opioid withdrawal; avoid concomitant use ( 7 ) Moderate (e.g., fluconazole) and strong (e.g., itraconazole) CYP3A4 inhibitors : Increased naldemedine concentrations; monitor for adverse reactions ( 7 ) P-gp inhibitors (e.g., cyclosporine) : Monitor for adverse reactions ( 7 )