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Long-Term Safety Data Reported for Oxycodone/Naltrexone (ALO-02) in Non-Cancer Pain
On October 11, Pfizer Inc. announced results from a phase III open-label, long-term safety study of the investigational agent ALO-02 (oxycodone hydrochloride and naltrexone hydrochloride extended-release capsules) in patients with moderate-to-severe chronic, non-cancer pain. The primary objective of the study was to evaluate the safety of ALO-02 administered for up to 12 months.
The study showed that the drug’s adverse-event profile was as expected, based on similar long-term safety studies with other extended-release opioid formulations; the most common adverse events were nausea, constipation, vomiting, and headache.
ALO-02 uses technology designed to discourage common methods of tampering associated with prescription opioid misuse and abuse. The drug consists of extended-release oxycodone pellets that surround a sequestered core of naltrexone. When used as directed, the naltrexone core remains sequestered, and patients receive oxycodone in an extended-release manner. When the pellets are crushed, the naltrexone is released and is designed to counteract the effects of oxycodone.
The new study included adult patients with moderate-to-severe chronic non-cancer pain lasting at least 3 months and requiring a continuous around-the-clock opioid analgesic for an extended period. Before enrolling in the study, the patients could receive a prescription opioid for the management of chronic pain or could be opioid-naïve. The primary objective of this single-arm, multicenter, safety study was to evaluate the long-term safety of ALO-02 administered once or twice daily for up to 12 months.
The study enrolled 395 patients, most of whom (77%) were opioid-experienced. The majority of patients had chronic lower back pain (61%), and some (18%) had pain from osteoarthritis. Patients enrolled in the study had experienced pain for an average of 9 years. A total of 193 patients (49%) received ALO-02 for approximately 6 months, and 105 patients (27%) received the drug for approximately 1 year.
The most common treatment-emergent adverse events while on ALO-02 were nausea, constipation, vomiting, and headache. The most common serious adverse events were acute myocardial infarction, non-cardiac chest pain, pneumonia, convulsion, and kidney stones.
A total of 237 patients (60%) discontinued the study over the 1-year study period, with 19% of patients reporting adverse events as the primary reason for discontinuation. The adverse events that most commonly led to discontinuation were nausea and constipation. The discontinuation rate was within the expected range, based on similar long-term safety studies with other extended-release opioid formulations.
For more information, visit the Pfizer Web site.