This study is a prospective, single-arm, multicenter, real-world study to evaluate effect of bowel function, analgesic effect, quality of life, and safety of Mimeixin® in Chinese patients with severe cancer pain.

Cancer remains a significant health concern globally, with rising incidence and mortality rates. In 2022, there were 19.96 million new cancer cases and 9.74 million cancer deaths worldwide, including 4.8 million new cases and 2.6 million deaths in China. Cancer patients often experience pain during treatment, with 40% of patients reporting persistent pain, particularly moderate to severe pain, occurring in 40%-80% of cases. Unrelieved pain can exacerbate symptoms such as anxiety, depression, fatigue, insomnia, and loss of appetite, significantly impacting patients' quality of life. Opioids, represented by morphine and oxycodone, are widely used for the treatment of moderate to severe cancer pain.

Long-term opioid use often leads to gastrointestinal adverse events, with opioid-induced constipation (OIC) being the most common, significantly affecting patients' quality of life and treatment compliance. Although some guidelines recommend laxatives as prophylactic and first-line treatment for OIC, approximately half of the patients do not experience adequate symptom improvement. The mechanism of OIC primarily involves the activation of intestinal μ-opioid receptors, which is difficult to address solely with laxatives. The key to treating OIC lies in blocking the stimulation of μ-opioid receptors in the gastrointestinal tract while maintaining the analgesic effect of opioid receptors in the central nervous system.

Oxycodone/naloxone sustained-release tablets, a combination of the opioid receptor agonist oxycodone and the antagonist naloxone, effectively provide analgesia while improving OIC. Foreign studies have demonstrated that this medication significantly improves OIC while maintaining good analgesic effects, with good long-term tolerability. Mimeixin® is an oxycodone/naloxone sustained-release tablet developed with reference to the foreign-listed drug Targin®. It was approved by the National Medical Products Administration of China in June 2024 for the treatment of severe pain in adults that requires opioid analgesics for adequate control. However, clinical validation has not been conducted among Chinese cancer pain patients. Therefore, a prospective, single-arm, multicenter, real-world study is planned to evaluate the effect in bowel function, analgesic effect, quality of life, and safety of Mimeixin® in Chinese patients with severe cancer pain in real-world clinical practice.

Inclusion Criteria:

• Age ≥ 18 years old, with a histological or pathological diagnosis of advanced cancer.
• Be diagnosed with severe (NRS ≥ 7 points) cancer pain, requiring regular opioid therapy.
• Diagnosed with OIC according to the Rome IV diagnostic criteria for OIC, with a BFI score ≥ 30.
• Determined by the investigator to be eligible for treatment with oxycodone/naloxone sustained-release tablets.
• Estimated survival period of more than 3 months.
• Voluntarily sign an informed consent form.

Exclusion Criteria:

• Patients with contraindications to oxycodone/naloxone sustained-release tablets (including allergy to the active ingredients or any excipients of this product; severe respiratory depression accompanied by hypoxemia and/or hypercapnia; severe chronic obstructive pulmonary disease; pulmonary heart disease; severe bronchial asthma; paralytic ileus caused by non-opioid drugs; moderate to severe liver function impairment).
• Patients with structural malformations of the gastrointestinal tract (such as intestinal obstruction, stenosis), other known gastrointestinal diseases/symptoms (including cancer metastasis to the digestive tract), or gastrointestinal digestion and absorption disorders.
• Patients with language communication barriers, cognitive impairments or mental illnesses, intracranial metastasis of tumors with consciousness disorders, or consciousness disorders caused by other reasons.
• Other situations that the investigator judges as unsuitable for inclusion in the study.