Widespread brain distribution and activity following i.c.v. infusion of anti-β-secretase (BACE1) in nonhuman primates

BACKGROUND AND PURPOSE

The potential for therapeutic antibody treatment of neurological diseases is limited by poor penetration across the blood-brain barrier. I.c.v. delivery is a promising route to the brain; however, it is unclear how efficiently antibodies delivered i.c.v. penetrate the cerebrospinal spinal fluid (CSF)-brain barrier and distribute throughout the brain parenchyma.

EXPERIMENTAL APPROACH

We evaluated the pharmacokinetics and pharmacodynamics of an inhibitory monoclonal antibody against β-secretase 1 (anti-BACE1) following continuous infusion into the left lateral ventricle of healthy adult cynomolgus monkeys.

KEY RESULTS

Animals infused with anti-BACE1 i.c.v. showed a robust and sustained reduction (~70%) of CSF amyloid-β (Aβ) peptides. Antibody distribution was near uniform across the brain parenchyma, ranging from 20 to 40 nM, resulting in a ~50% reduction of Aβ in the cortical parenchyma. In contrast, animals administered anti-BACE1 i.v. showed no significant change in CSF or cortical Aβ levels and had a low (~0.6 nM) antibody concentration in the brain.

CONCLUSION AND IMPLICATIONS

I.c.v. administration of anti-BACE1 resulted in enhanced BACE1 target engagement and inhibition, with a corresponding dramatic reduction in CNS Aβ concentrations, due to enhanced brain exposure to antibody.

WITHDRAWN: Comparative efficacy of epidural, subarachnoid, and intracerebroventricular opioids in patients with pain due to cancer

2013: This review is now being updated by a new author team. The publication of the protocol is expected in late 2013.

October 2015: after discussion with the authors and PaPaS editors, the decision was made to halt the development of the protocol that was being planned to replace and update this review. It was felt that the review question was no longer a priority.

The editorial group responsible for this previously published document have withdrawn it from publication.

Intracerebroventricular opioids for intractable pain

When pain is refractory to systemic opioid and non-opioid analgesic therapy and palliative chemoradiation or ablative or stimulant neurosurgical procedures are not possible, palliative treatment becomes limited, particularly if the patient wishes to be at home at the end of life. Intracerebroventricular (ICV) infusion of morphine in the home setting might be presented as an option. The present article reviews the basic and clinical evidence of the efficacy and safety of ICV administration of opioids. Information was gathered from various bibliographic sources, including PubMed and others, and summarized and evaluated to assess the efficacy and safety of ICV opioids for pain relief. Results from ICV infusion of morphine into terminally ill patients refractory to other pain treatments have been reported since the early 1980s. Good efficacy has been achieved for the vast majority of patients, without serious development of analgesic tolerance. There have also been a low incidence of adverse effects, such as constipation and respiratory depression, and a significant retention of alertness associated with this route of administration. Intracerebroventricular infusion of opioid analgesics thus appears to be a safe and effective therapy for the palliative treatment of refractory pain.

Intrathecal pumps

Direct neuroaxis drug delivery has expanded the physician's armamentarium to provide treatment options to those who have failed more conservative interventions. Starting from Bier's 'cocainization of the spinal cord' in 1898, direct nervous system pharmacy delivery has long been recognized as an effective means to treat pain. Intrathecal pump systems are now commonplace in the management of numerous pain states, as well as of neuromuscular sequelae of central nervous system injury. There has been much advancement in the physiologic and pharmacologic understanding of direct neuromodulation, providing a growing number of treatment options depending on the specific disease state. As well, surgical techniques and catheter systems have undergone refinements providing improved long-term safety and efficacy. We present a review of the historical evolution to current intrathecal therapies, as well as a dialog regarding patient selection, drug options, and side effects. Also, included is a discussion of surgical techniques, current delivery options and complications concerning pump placement.

Comparative efficacy of epidural, subarachnoid, and intracerebroventricular opioids in patients with pain due to cancer

BACKGROUND

Since the 1970s, when endogenous opioids and opioid receptors were first isolated in the central nervous system, attempts have been made to optimize opioid therapy by delivering the medication centrally rather than systemically. Although the vast majority of cancer patients obtain satisfactory pain relief from individualized systemic treatment, there remain the few whose pain is refractory to systemic treatments. These patients may obtain relief from neuraxial opioid therapy: intracerebroventricular, epidural or subarachnoid.

OBJECTIVES

To compare intracerebroventricular therapy with other neuraxial treatments and to determine whether intracerebroventricular (ICV) has anything to offer over epidural (EPI) and subarachnoid (SA) catheters in terms of efficacy, adverse effects, and complications.

SEARCH STRATEGY

A number of electronic databases were searched to retrieve information for inclusion in this review. Non-English language reports are awaiting assessment. Unpublished data were not sought.

SELECTION CRITERIA

Randomised studies of intracerebroventricular therapy for patients with intractable cancer pain were sought. However, this level of evidence was not available so data from uncontrolled trials, retrospective case series and uncontrolled prospective cohort studies were assessed.

DATA COLLECTION AND ANALYSIS

Our search did not retrieve any controlled trials. We therefore used data from uncontrolled studies to compare incidences of analgesic efficacy, adverse effects, and complications. We found 72 uncontrolled trials assessing ICV (13 trials, 337 patients), EPI (31 trials, 1343 patients), and SA (28 trials, 722 patients) in cancer patients. From these we extracted data on analgesic efficacy, common pharmacologic adverse effects, and complications.

MAIN RESULTS

Data from uncontrolled studies reported excellent pain relief among 73% of ICV patients compared with 72% EPI and 62% SA. Unsatisfactory pain relief was low in all treatment groups. Persistent nausea, persistent and transient urinary retention, transient pruritus, and constipation occurred more frequently with EPI and SA. Respiratory depression, sedation and confusion were most common with ICV. The incidence of major infection when pumps were used with EPI and SA was zero. There was a lower incidence of other complications with ICV therapy than with EPI or SA.

AUTHORS' CONCLUSIONS

Neuraxial opioid therapy is often effective for treating cancer pain that has not been adequately controlled by systemic treatment. However, long-term use of neuraxial therapy can be complicated by problems associated with the catheters. The data from uncontrolled studies suggests that ICV is at least as effective against pain as other neuraxial treatments and may be a successful treatment for patients whose cancer pain is resistant to other treatments.

Supportive therapy of elderly cancer patients

Elderly cancer patients often require supportive care due to the physiologic decline of organs and apparatus linked with the aging process per se, and for the effects of tumor or of anticancer treatments. Pain and nutritional deficits are some clinical aspects requiring supportive care. Lack of studies on these latter topics does not allow an in depth analysis of the problem. The present review deals with literature concerning pain and nutritional problems in the general cancer population with emphasis on aspects typical for elderly cancer subjects. Physiologic and cancer-related changes in body composition, physical function and cognitive capacity of the elderly are presented and, when appropriate, linked with pathogenetic factors of pain and malnutrition, as well as their treatment. Pain demographic data, pain intensity evaluation and currently available techniques to provide pain relief such as etiologic treatment, analgesic pharmacotherapy and invasive analgesic procedures, are extensively discussed. Causes and assessment of malnutrition as well as available nutritional approaches such as oral, enteral and parenteral nutrition are also debated.

Pain and loss of function in head and neck cancer survivors

Head and neck cancers are relatively uncommon malignancies and the characteristics of pain and functional impairments in survivors are not well studied. To characterize the incidence, location, severity, types and causes of pain; associated functional impairments, and pain management methods, the medical charts of 40 consecutive outpatients with biopsy-proven head and neck cancers were reviewed. Pain was severe in 52% (N = 21), and was located near sites of tumor origin. Pain was caused by tumor recurrence in 35% (N = 14), treatment sequelae in 30% (N = 12), multiple etiologies in 25% (N = 10), and unrelated causes in 10% (N = 4). Pains were mixed nociceptive and neuropathic pain in 37.5% (N = 15), nociceptive pain in 32.5% (N = 13), myofascial in 13.0% (N = 6), neuropathic in 7.5% (N = 3); and other mixed types in 7.5% (N = 3). Despite the high prevalence of dysphagia (82%), 60% used orally administered opioid-nonopioid analgesics. Physical disfigurement (87.5%; N = 35), dysphagia (62.5%, N = 25), and jaw dysfunction (40.0%; N = 16) were the most frequent physical impairments. Multiple regression analysis showed that the presence of skull base or mandibular bone involvement had significant influence on the severity of pain (P = 0.03, adjusted R2 0.25) We conclude that pain in head and neck cancer can be chronic, severe, and persistent despite completion of oncologic treatment.

Epileptic seizure associated with intracerebroventricular and intrathecal morphine bolus

We report on two patients with morphine-related seizures associated with either intrathecal or intracerebroventricular administration. Both patients had a history of malignant tumor and both experienced the seizures following bolus application of morphine, while even higher dosages were well tolerated when continuously infused. Seizures occurred without signs of intoxication. Initiation of intrathecal morphine therapy and bolus application should be performed carefully and only when constant monitoring is provided for at least 12 h. Animal data and possible mechanisms for morphine-related seizures are discussed.

Intraventricular administration of morphine for control of intractable cancer pain in 90 patients

OBJECTIVE

To quantitate the relief of intractable cancer pain by the use of intraventricular morphine administration.

METHODS

Intraventricular morphine administration was performed through an Ommaya reservoir. An initial dose of 0.25 mg of morphine sulfate per 24 hours was administered to all of the patients. This dose was progressively increased in 0.25-mg increments until optimal analgesia was attained.

RESULTS

Sixty men and 30 women with a median age of 58 years (range, 23-80 yr) entered the study. The median duration of pain was 6 months (range, 0.5-120 mo). A daily morphine dose of up to 1 mg was adequate to achieve an analgesic effect in 77% of the patients. Only nine patients (10%) achieved < 50% pain relief. Using a multiple regression analysis, only the morphine dosage was found to be an independent prognostic factor. The most frequent side effect (22%) was nausea/vomiting. Also, there were two patients with opioid intolerance and two with intracerebral hematomas. Three reservoirs failed.

CONCLUSION

Intraventricular morphine administration is a useful method for palliation of intractable cancer pain.

Invasive techniques in the management of cancer pain

Familiarity with potentially useful anesthetic and neurosurgical techniques is important in the management of patients who are unable to achieve a satisfactory balance between analgesia and side effects from systemic analgesic therapies. The ability to make specific recommendations is limited by the paucity of controlled data, incorporating details of pain syndromes, prior therapies, validated pain assessment, meticulous reporting of adverse effects, and longitudinal follow-up.

Intraventricular morphine for intractable pain of advanced cancer

Among the most difficult pain management problems are those associated with advanced head and neck cancer, and those in which pain is midline, bilateral, or diffuse. The authors report effective control of intractable pain in 52 patients by injection of small doses of morphine via an Ommaya or a Cordis reservoir into the lateral cerebral ventricle. The technique is safe and effective. The reservoir is usually inserted under local analgesia so the method of pain relief is available to patients in whom general anesthesia would be difficult or contraindicated. The doses of morphine required to maintain analgesia remain remarkably low. Tolerance reported by other authors has not been a problem when preoperative assessment of the patient has been thorough. Maximum survival time has been 75 wk and another patient has lived 65 wk. Complications included two colonized reservoirs, one dislodged ventricular catheter, three blocked catheters, and one postoperative meningitis. For patients with diffuse midline or bilateral pain, or intractable pain associated with advanced head and neck cancer, the use of intraventricular morphine should be considered when satisfactory pain relief is not achieved with oral morphine or continuous subcutaneous infusion.

Validation of World Health Organization guidelines for pain relief in head and neck cancer. A prospective study

In a prospective study of 167 patients with head and neck cancer, we assessed the causes and mechanisms of pain, as well as the efficacy and side effects of analgesic treatment, along World Health Organization (WHO) guidelines. The majority of patients had pain caused by cancer (83%) and/or treatment (28%), 4% had pain due to debility, and 7% had pain unrelated to cancer. Palliative antineoplastic treatment was performed in 32% of patients. Systemic analgesics were administered on 97% of a total of 8,106 treatment days, and coanalgesics or adjuvant drugs on 100%. The treatment proved to be very successful, as severe pain was experienced only during 5% of the observation period. In the absence of serious side effects, the most frequent symptoms observed were insomnia, dysphagia, anorexia, constipation, and nausea. The use of analgesic and adjuvant drugs along WHO guidelines to treat pain in head and neck cancer is highly effective and relatively safe.