A Study to Evaluate the Safety and Effectiveness of ALKS 2680 in Subjects With Narcolepsy Type 1 (ALKS 2680-201)

The purpose of this research study is to assess the safety and efficacy of ALKS 2680 compared to placebo, including whether participants taking ALKS 2680 experience a greater decrease in sleepiness and a decrease in cataplexy ("sudden loss of muscle control"), compared to participants taking placebo alone.

Inclusion Criteria: * 18-70 years of age * Has a BMI ≥18 and ≤40 kg/m2 * Meets the diagnostic criteria of Narcolepsy type 1 according to ICSD-3-TR guidelines. Additionally, meets the following criteria: * Is HLA-DQB1\*06:02-positive * Has residual excessive daytime sleepiness and cataplexy * Is willing and able to discontinue any medications prescribed for the management of narcolepsy symptoms for at least 14 days and for the duration of study * Is willing to adhere to additional protocol requirements Exclusion Criteria: * Significant comorbid medical conditions, including other sleep, cardiovascular, psychiatric, hepatic or other disorders may be exclusionary; eligibility will be determined on an individual basis by the study investigator * Is currently pregnant, breastfeeding, or planning to become pregnant during the study * Is currently enrolled in another clinical study (other than the parent study) or used any investigational drug or device within 30 days prior to Screening