Drug liking assesses the degree that a participant likes a drug effect at the time the question is being asked (that is, at the moment). It is scored using a 100 millimeter (mm) bipolar VAS anchored in the center with a neutral anchor of "neither like nor dislike" (score of 50 mm), on the extreme left with "strong disliking" (score of 0 mm) and on the extreme right with "strong liking" (score of 100 mm). Peak Effect (Emax) = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose Pharmacodynamic (PD) data from each period.

Drug liking assesses the degree that a participant likes a drug effect at the time the question is being asked (that is, at the moment). It is scored using a 100 millimeter (mm) bipolar VAS anchored in the center with a neutral anchor of "neither like nor dislike" (score of 50 mm), on the extreme left with "strong disliking" (score of 0 mm) and on the extreme right with "strong liking" (score of 100 mm). AUE (0-2) = Area under the effect versus time curve from time 0 to 2 hours.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

High VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

High VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-2) = Area under the effect versus time curve from time 0 to 2 hours.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Take drug again VAS is a subjective assessment of the degree to which a participant would desire to take the drug again if given the opportunity. It is presented on a 100 mm VAS with score ranging from 0 mm to 100 mm (score of 0 mm = "definitely would not", 50 mm = "do not care", and 100 mm = "definitely would"). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Take drug again VAS is a subjective assessment of the degree to which a participant would desire to take the drug again if given the opportunity. It is presented on a 100 mm VAS with score ranging from 0 mm to 100 mm (score of 0 mm = "definitely would not", 50 mm = "do not care", and 100 mm = "definitely would"). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Take drug again VAS is a subjective assessment of the degree to which a participant would desire to take the drug again if given the opportunity. It is presented on a 100 mm VAS with score ranging from 0 mm to 100 mm (score of 0 mm = "definitely would not", 50 mm = "do not care", and 100 mm = "definitely would"). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Take drug again VAS is a subjective assessment of the degree to which a participant would desire to take the drug again if given the opportunity. It is presented on a 100 mm VAS with score ranging from 0 mm to 100 mm (score of 0 mm = "definitely would not", 50 mm = "do not care", and 100 mm = "definitely would"). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Overall drug liking VAS assesses the participant's global perception of drug liking (that is, effects over the whole course of the drug experience including any carry-over effects). A 100 mm VAS is used to assess response based on a score ranging from 0 mm to 100 mm (0 mm = "strong disliking", 50 mm = "neither like nor dislike", and 100 mm= "strong liking"). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Overall drug liking VAS assesses the participant's global perception of drug liking (that is, effects over the whole course of the drug experience including any carry-over effects). A 100 mm VAS is used to assess response based on a score ranging from 0 mm to 100 mm (0 mm = "strong disliking", 50 mm = "neither like nor dislike", and 100 mm= "strong liking"). Emean = Average observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Overall drug liking VAS assesses the participant's global perception of drug liking (that is, effects over the whole course of the drug experience including any carry-over effects). A 100 mm VAS is used to assess response based on a score ranging from 0 mm to 100 mm (0 mm = "strong disliking", 50 mm = "neither like nor dislike", and 100 mm= "strong liking"). Emin= Average observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Overall drug liking VAS assesses the participant's global perception of drug liking (that is, effects over the whole course of the drug experience including any carry-over effects). A 100 mm VAS is used to assess response based on a score ranging from 0 mm to 100 mm (0 mm = "strong disliking", 50 mm = "neither like nor dislike", and 100 mm= "strong liking").

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Any Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Any Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Any Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Good Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Good Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Good Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Bad Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Bad Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Bad Drug Effects VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Feel Sick VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Feel Sick VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Feel Sick VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Nausea VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Nausea VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Nausea VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Sleepy VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Sleepy VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from a response of 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Sleepy VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from a response of 'none' (score of 0 mm)to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Dizzy VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Dizzy VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from a response of 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Dizzy VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from a response of 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Pupillometry assessments measure change in pupil size (miosis) as an indicator of opioid pharmacological properties. Participants have the size of pupil measured using a pupillometer. Measurements are made in a dimly lit (mesopic) room with controlled lighting conditions. The same eye for each participant was used for all measurements during the study. Emax = Maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Pupillometry assessments measure change in pupil size (miosis) as an indicator of opioid pharmacological properties. Participants have the size of pupil measured using a pupillometer. Measurements are made in a dimly lit (mesopic) room with controlled lighting conditions. The same eye for each participant was used for all measurements during the study. AUE (0-x) = Area under the effect versus time curve from time zero to time of last quantifiable effect (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Pupillometry assessments measure change in pupil size (miosis) as an indicator of opioid pharmacological properties. Participants have the size of pupil measured using a pupillometer. Measurements are made in a dimly lit (mesopic) room with controlled lighting conditions. The same eye for each participant was used for all measurements during the study. TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Drug liking assesses the degree that a participant likes a drug effect at the time the question is being asked (that is, at the moment). It is scored using a 100 mm bipolar VAS anchored in the center with a neutral anchor of "neither like nor dislike" (score of 50 mm), on the left with "strong disliking" (score of 0 mm) and on the right with "strong liking" (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time 0 to x hours (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Drug liking assesses the degree that a participant likes a drug effect at the time the question is being asked (that is, at the moment). It is scored using a 100 mm bipolar VAS anchored in the center with a neutral anchor of "neither like nor dislike" (score of 50 mm), on the left with "strong disliking" (score of 0 mm) and on the right with "strong liking" (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

High VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). AUE (0-x) = Area under the effect versus time curve from time 0 to x hours (0-x).

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

High VAS assesses the effect experienced by the participant on a 100 mm unipolar VAS, where responses are unidirectional and range from 'none' (score of 0 mm) to 'extremely' (score of 100 mm). TEmax = Time to maximum observed score.

Completer analysis set included all randomized participants who completed all 6 periods of treatment phase and who contributed to post-dose PD data from each period.

Cmax[dn]=Dose normalized maximum observed plasma concentration of participants who received oxycodone and ALO-02 were reported. Oxymorphone and noroxycodone are metabolites of oxycodone.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the Pharmacokinetic (PK) parameters of interest. Here 'n' signifies those participants who were evaluable for specified category.

Participants who received ALO-02 were reported. 6-Beta-naltrexol is metabolites of naltrexone.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest.

Participants who received oxycodone and ALO-02 were reported. Oxymorphone and noroxycodone are metabolites of oxycodone.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest. Here 'n' signifies those participants who were evaluable for specified category.

Participants who received ALO-02 were reported. 6-Beta-naltrexol is metabolites of naltrexone.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest. Here 'n' signifies those participants who were evaluable for specified category.

Participants who received oxycodone and ALO-02 were reported. Oxymorphone and noroxycodone are metabolites of oxycodone.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest. Here 'N' (number of participants analyzed) signifies those participants evaluable for this measure.

AUC is a measure of the serum concentration of the drug over time. It is used to characterize drug absorption. Participants who received oxycodone were reported.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest.

Area under the plasma concentration time-curve from zero to the last quantifiable concentration (AUClast). Participants who received oxycodone were reported.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest.

[AUC (0 - ∞)dn]= Dose normalized area under the plasma concentration versus time curve [AUC(dn)] from time zero (pre-dose) to extrapolated infinite time (0 - ∞). It is obtained from AUC (0- t) plus AUC (t - ∞). Participants who received oxycodone were reported. Participants who received oxycodone were reported.

Parameter analysis set included all enrolled participants who received at least 1 dose of study drug and who had at least 1 of the PK parameters of interest. Here 'N' (number of participants analyzed) signifies those participants evaluable for this measure.

An AE was any untoward medical occurrence in a participant who received study medication without regard to possibility of causal relationship. SAE: an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 3 - 7 days following last study drug administration. Symptoms of withdrawal following naloxone administration (naloxone challenge phase) were not collected as adverse events unless they met the criteria for an SAE. AEs included SAEs as well as non-serious AEs which occurred during the trial.

Safety analysis set included all participants who received at least 1 dose of study drug.

Vital signs assessment included measurement of heart rate, systolic and diastolic blood pressures, respiratory rate and oral temperature. Criteria for clinically significant change in any vital sign examination was based on investigator's discretion.

Safety analysis set included all participants who received at least 1 dose of study drug.

End-tidal carbon dioxide concentration in the expired air (EtCO2) was monitored using capnography in a sitting position. Criteria for clinically significant change in EtCO2 was based on investigator's discretion.

Safety analysis set included all participants who received at least 1 dose of study drug. This outcome measure was not planned to be analyzed in "Naloxone Challenge Phase", as pre-specified in protocol.

Oxygen saturation of hemoglobin in blood (SpO2) was monitored using pulse oximetry continuously for 5 hours following dosing in the drug discrimination phase and continuously for 12 hours following dosing in the treatment phase, or longer at the discretion of the investigator. Individual measurements was collected in a sitting position. If SpO2 fall below 90 percent (%), the investigator might had administered oxygen via nasal cannula at a flow rate sufficient to maintain the SpO2 greater than or equal to 90%. Participants with fall in SpO2 below 90% were reported.

Safety analysis set included all participants who received at least 1 dose of study drug. This outcome measure was not planned to be analyzed in "Naloxone Challenge Phase", as pre-specified in protocol.