The primary objective is to assess the efficacy of oxycodone/naloxone (OXN) for the management of opioid-induced constipation (OIC) compared to oxycodone controlled-release tablets (OXY) in subjects with moderate to severe low back pain and OIC who require around-the-clock opioid therapy.

Inclusion Criteria include:

• Male and female subjects ≥ 18 years of age with moderate to severe, chronic low back pain (lasting at least several hours daily) as their predominant pain condition for at least 3 months prior to screening period;
• The low back pain must be related to nonmalignant and nonneuropathic conditions and may be with or without radiation;
• Subjects must have a self-reported history of opioid induced constipation (OIC).

Exclusion Criteria include:

• Subjects with rheumatoid arthritis or other inflammatory arthritis;
• Subjects with neuropathic conditions that have been painful or required therapy within the past 3 months;
• Subjects with evidence of significant structural abnormalities of the gastrointestinal (GI) tract or other significant conditions affecting GI motility;
• Subjects with chronic constipation not related to opioid use;
• Subjects who had surgical procedures directed towards the source of chronic low back pain within 6 months of the screening visit or planned during the study;
• Subjects with a history of malignancy within the past 2 years, with the exception of basal cell carcinoma that has been successfully treated.

Other protocol specific inclusion/exclusion criteria may apply.