Compare the Efficacy and Safety of Intranasal Esketamine in Chronic Opioid Refractory Pain

IMPORTANCE Trial - A Provisional Study-design of a Single-center, Phase II, Double-blinded, Placebo-controlled, Randomized, 4-week Study to Compare the Efficacy and Safety of Intranasal Esketamine in Chronic Opioid Refractory Pain

This study is to assess the efficacy and safety of a four-week treatment with intranasal esketamine (56 mg) twice a week combined with opioid analgesic and adjuvant standard therapy in the management of adult patients with severe and opioid refractory chronic cancer pain.

Inclusion Criteria:

• Patient with refractory cancer pain, this pain defined when:

  • Multiple evidence- based biomedical therapies used in a clinically appropriate and acceptable fashion have failed to reach treatment goals that mainly include adequate pain reduction and/or improvement in daily living functioning activities.
  • Patients' functional activities do not allow a quality of life which is acceptable and/or pharmaceutical therapies have resulted in intolerable adverse effects.

• Psychiatric disorders and psychosocial factors that could influence pain outcomes have been assessed and appropriately addressed

• Cancer pain classified as chronic (persistent or recurrent pain lasting longer than 3 months), and currently refractory despite optimized analgesic therapy including an opioid.

  • Optimized analgesic therapy is arbitrarily defined as: oral morphine equivalent of 60 mg/d or more (or another strong opioid at optimized dose) plus at least one adjuvant analgesic drug, for at least 2 weeks.

• No increase in baseline long acting opioid dose or addition of a new adjuvant analgesic drug within 2 weeks prior to study entry

• Ability to communicate the intensity of pain using the NPRS pain scale ranging from (0 as no pain to 10 with severe pain).

• Ability to give fully informed written consent.

• Expect survival more than 3 months.

Exclusion Criteria:

• History of allergy or intolerance to esketamine or ketamine.
• History of allergy to disinfecting products containing quaternary ammonium, who might be susceptible to be allergic to denatonium benzoate.
• Concomitant use of xanthine derivatives (e.g. aminophylline, theophylline), ergometrine, or monoamine oxidase inhibitors.
• Active nasal/sinus dysfunction (e.g. allergic or infectious rhinitis) or presence of any lesion of the nasal mucosa.
• Pregnancy, breastfeeding and women of childbearing potential not using a highly effective contraception method.
• Uncontrolled hypertension, arrhythmia, heart failure, or untreated coronary artery disease. History of transient ischemic attacks, stroke, neurovascular disease, hemorrhage, severe head injury, hydrocephalus or elevated intracranial pressure within the last 3 months.
• History of primary or metastatic malignant brain lesions (uncontrolled or without previous treatment).
• Known aneurysmal vascular disease (including thoracic and abdominal aorta, intracranial, and peripheral arterial vessels) or arteriovenous malformation
• Uncontrolled psychiatric illness with psychosis/ hallucination (e.g. schizophrenia, acute psychosis).
• Alcohol abuse, drug abuse/ dependence within the past 6 months as self-reported.
• Cirrhosis or severe hepatic impairment defined as 5-fold elevation of transaminases
• Uncontrolled hyperthyroidism.
• Globe injuries or increased intraocular pressure (e.g. glaucoma).
• History of ulcerative or interstitial cystitis.
• Subjects scheduled to receive radiotherapy (RT) to a site of pain during the study period, or who have received RT to a site of pain within 2 weeks before study entry.
• Subjects scheduled to undergo surgical treatment during the study period likely to affect pain.
• Subjects on or starting chemotherapy if there is a significant expectation of that therapy affecting pain.
• Subjects who have not provided signed informed consent form.
• Concomitant use of drugs moderately or severely affecting cytochrome P450 activity.