PK results suggested product did not meet requirement for further development.

The purpose of this study is to evaluate the safety of the matrix fentanyl patch ZR-02-01 in providing relief of non-malignant chronic pain.

This study will evaluate the safety of the matrix fentanyl patch. The study will be conducted in opioid-tolerant patients with moderate to severe non-malignant chronic pain currently taking an around-the-clock opioid. Patients will discontinue their current opioid regimen and begin using ZR-02-01 as soon as possible under the direction of the physician investigator upon entry into the study. Patient's dose of ZR 02 01 will be determined by the investigator using sponsor-provided conversion. Pain therapy will be under the supervision of the physician investigator.

Inclusion Criteria:

• Patient is at least 18 and no older than 75 years of age
• Patient has moderate to severe, non-malignant chronic pain that is expected to last for at least 12 months and is currently taking an around-the-clock opioid to treat his/her pain
• Patient is already receiving opioid therapy, has demonstrated opioid tolerance, and requires a total daily dose of opioids at least equivalent to 25 mcg/hr of transdermal fentanyl. Patients who are considered opioid-tolerant are those who have been taking a daily dose of at least 30 mg of oral morphine or morphine equivalent opioid for at least 2 weeks.

Exclusion Criteria:

• Patient has active cancer
• Patient has a history of substance abuse or has a substance abuse disorder