Intrathecal Bolus Research Articles

Safety, tolerability, and pharmacokinetics of antisense oligonucleotide BIIB078 in adults with C9orf72-associated amyotrophic lateral sclerosis: a phase 1, randomised, double blinded, placebo-controlled, multiple ascending dose study

Hexanucleotide repeat expansion of C9orf72 is a common genetic cause of amyotrophic lateral sclerosis (ALS). No C9orf72-targeted treatments are available. BIIB078 is an investigational antisense oligonucleotide targeting C9orf72 sense RNA. We aimed to assess the safety, tolerability, and pharmacokinetics of BIIB078 in participants with C9orf72-associated ALS. This phase 1, randomised controlled trial was done at 22 sites in six countries (Canada, Ireland, Netherlands, Switzerland, UK, and USA). Adults with ALS and a pathogenic repeat expansion in C9orf72 were randomly assigned within six cohorts, via Interactive Response Technology in a 3:1 ratio per cohort, to receive BIIB078 (5 mg, 10 mg, 20 mg, 35 mg, 60 mg, or 90 mg in cohorts 1-6, respectively) or placebo, via an intrathecal bolus injection. The treatment period consisted of three loading doses of study treatment, administered approximately once every 2 weeks, followed by monthly maintenance doses during a treatment period of about 3 months for cohorts 1-3 and about 6 months for cohorts 4-6. Patients and investigators were masked to treatment assignment. The primary endpoint was the incidence of adverse events and serious adverse events. This trial was registered with ClinicalTrials.gov (NCT03626012) and is completed. Between Sept 10, 2018, and Nov 17, 2021, 124 patients were screened for inclusion in the study. 18 patients were excluded and 106 participants were enrolled and randomly assigned to receive 5 mg (n=6), 10 mg (n=9), 20 mg (n=9), 35 mg (n=19), 60 mg (n=18), or 90 mg (n=18) of BIIB078, or placebo (n=27). 58 (55%) of 106 patients were female. All patients received at least one dose of study treatment and were included in all analyses. All participants had at least one adverse event; most adverse events were mild or moderate in severity and did not lead to treatment discontinuation. The most common adverse events in BIIB078-treated participants were falls, procedural pain, headache, and post lumbar puncture syndrome. 14 (18%) of 79 patients who received any dose of BIIB078 reported serious adverse events, compared with nine (33%) of 27 patients who received placebo. Five participants who received BIIB078 and three participants who received placebo had fatal adverse events: respiratory failure in a participant who received 10 mg BIIB078, ALS worsening in two participants who received 35 mg BIIB078, traumatic intracerebral haemorrhage in one participant who received 35 mg BIIB078, pulmonary embolism in one participant who received 60 mg BIIB078, and respiratory failure in three participants who received placebo. All deaths were assessed as not related to the study treatment by the reporting investigator. On the basis of these phase 1 study results, including secondary and exploratory findings showing no reduction in neurofilament levels and no benefit on clinical outcomes relative to the placebo cohort, BIIB078 clinical development has been discontinued. However, these results will be informative in furthering our understanding of the complex pathobiology of C9orf72-associated ALS. Biogen.

Programmed Intermittent Intrathecal Bolus for Maintenance of Labor Analgesia in an Obstetric Patient: A Case Report

Maintenance of labor analgesia with programmed intermittent epidural boluses (PIEBs) has demonstrated benefits over the use of continuous infusions. While programmed intermittent boluses have been used for the maintenance of epidural analgesia, it has not been reported for the maintenance of intrathecal analgesia. Approximately 25% of intrathecal catheters (ITC) ultimately fail, often due to inadequate analgesic coverage. We describe the use of programmed intermittent intrathecal boluses for a laboring parturient who received an ITC. She reported excellent pain relief without significant motor block, high anesthetic block, hypotension, or respiratory distress. This delivery modality may increase the rate of ITC after unintentional dural puncture (UDP).

Tau-targeting antisense oligonucleotide MAPTRx in mild Alzheimer’s disease: a phase 1b, randomized, placebo-controlled trial

Tau plays a key role in Alzheimer’s disease (AD) pathophysiology, and accumulating evidence suggests that lowering tau may reduce this pathology. We sought to inhibit MAPT expression with a tau-targeting antisense oligonucleotide (MAPTRx) and reduce tau levels in patients with mild AD. A randomized, double-blind, placebo-controlled, multiple-ascending dose phase 1b trial evaluated the safety, pharmacokinetics and target engagement of MAPTRx. Four ascending dose cohorts were enrolled sequentially and randomized 3:1 to intrathecal bolus administrations of MAPTRx or placebo every 4 or 12 weeks during the 13-week treatment period, followed by a 23 week post-treatment period. The primary endpoint was safety. The secondary endpoint was MAPTRx pharmacokinetics in cerebrospinal fluid (CSF). The prespecified key exploratory outcome was CSF total-tau protein concentration. Forty-six patients enrolled in the trial, of whom 34 were randomized to MAPTRx and 12 to placebo. Adverse events were reported in 94% of MAPTRx-treated patients and 75% of placebo-treated patients; all were mild or moderate. No serious adverse events were reported in MAPTRx-treated patients. Dose-dependent reduction in the CSF total-tau concentration was observed with greater than 50% mean reduction from baseline at 24 weeks post-last dose in the 60 mg (four doses) and 115 mg (two doses) MAPTRx groups. Clinicaltrials.gov registration number: NCT03186989.

Abstract TP124: Irraflow® Device (ventricular Irrigation And Drainage System) Achieves Optimal Clearance Of Intraventricular Hemorrhage (IVH)

Introduction: IVH clearance of more than 80% with intraventricular fibrinolysis administered via a conventional external ventricular drain (EVD) is associated with improvements in outcomes; however, 80% IVH clearance is difficult to achieve. The IRRAflow® device offers fluid irrigation and drainage in a unique system that is designed to provide efficient drainage and clearance of hemorrhage, which may provide advantages over a conventional EVD. The purpose of this study is to evaluate the radiographic findings and outcomes of patients with IVH associated with intracranial hemorrhage (ICH) or subarachnoid hemorrhage (SAH) who received treatment with the IRRAFlow® device from April 1, 2021, to May 1, 2022. Methods: This was a single center, retrospective review. The primary outcome was change in IVH volume which assessed by modified Graeb Scale (mGS). All endpoints were analyzed using descriptive statistics. Results: Twelve patients were identified during the study period. Four patients were not included in the analysis due to withdrawal of care (n=2) or severe stroke causing death before completion of treatment (n=2). Of the eight patients included in the study, two had IVH associated with SAH, and six had IVH associated with ICH. Four patients received intrathecal boluses of alteplase, and three patients also had a traditional EVD placed in additional to the ventricular flow device. Seven patients had a pre-treatment mGS greater than or equal to 5, and two patients had a pre-treatment mGS of 4. The mean (+/- SD) pre-treatment mGS was 14 (+/- 8), and post-treatment mGS was 2 (+/- 3). The mean (+/- SD) volume clearance, which was calculated using the mGS, was 92% (+/- 12%). All patients had a modified Rankin scale (mRS) of 4 prior to treatment. Mean (+/- SD) mRS was 3 (+/- 1) at post-discharge follow up. All patients achieved IVH clearance, with third and fourth ventricle clearance, except for one patient who removed the device prior to completion of therapy. None of the patients required ventriculoperitoneal shunt placement or died. One patient developed ventriculitis as a complication. Conclusion: In conclusion, the IRRAFlow® device was successful in achieving goal IVH clearance (mGS less than 5) in all patients, which has been associated with improved outcomes.

RTID-04. CLINICAL POTENTIAL OF TARGETING TRANSFORMING GROWTH FACTOR BETA 2 WITH OT-101 FOR POST-RADIATION CONSOLIDATION IN DIFFUSE INTRINSIC PONTINE GLIOMA

Abstract Diffuse intrinsic pontine glioma (DIPG) in children has a dismal prognosis with a median overall survival (OS) of 10 months and a 2-year overall survival rate of < 10% after standard radiation therapy. Chemotherapy does offer clinically meaningful benefits. Therefore, there is an urgent need for therapeutic innovations for treatment of pediatric DIPG. High-grade glioma cells, including pediatric glioblastoma and DIPG cells have been shown to produce transforming growth factor beta 2 (TGFB2) which has been implicated both as promoter of glioma cells and as a key contributor to the T-cell hyporesponsiveness of the tumor microenvironment (TME) towards glioma cells. OT-101 is a first-in-class RNA therapeutic designed to abrogate the immunosuppressive and tumor promoting actions of TGF-B2. At low micromolar concentrations, OT-101 reduces the TGFB2 secretion by human glioma cells, blocks their proliferation as well as migration, and restores the anti-glioma cytolytic function of patient-derived T-cells. In a Phase 2 clinical study, intracerebrally applied OT-101 administered via convection-enhanced delivery showed promising single agent activity in Recurrent/Refractory (R/R) high-grade glioma (HGG) (Uckun et al., Cancers. 2019 28;11(12):1892). The intrathecal administration of antineoplastic drugs directly in the CSF allows to bypass the selective filter of BBB, achieving significant concentrations of the antineoplastic agents in CSF, while reducing the likelihood of systemic toxicity. Informed by favorable safety pharmacology studies of intrathecally delivered OT-101 in rabbits and primates and encouraged by its single agent activity in adult patients with HGG, we decided to embark upon a multi-center, two-part, randomized Phase 1-2 study of OT-101 in pediatric patients with DIPG. Multiple doses of OT-101 will be administered after completion of radiation therapy as intrathecal bolus injections. The study is designed to determine: 1) the maximum tolerated dose (MTD) or recommended Phase 2 dose (RP2D) of OT-101, and 2) its efficacy in children with DIPG.

DDEL-16. DELIVERY OF OT-101 - TGF-Β ANTISENSE- FOR THE TREATMENT OF GLIOBLASTOMA

Abstract OT-101 - a TGF-beta antisense- is active against recurrent glioblastoma in G004- a phase 2 clinical trial [Uckun FM, Qazi S, Hwang L, Trieu VN. Recurrent or refractory high grade gliomas treated by convection enhanced delivery of a TGF-beta2 targeting RNA therapeutic: a post-hoc analysis with long-term follow up. Cancers. 2019, 11:1892]. OT-101 was delivered intratumorally by Convection Enhanced Delivery (CED). To further expand the application of OT-101, we explored the intrathecal delivery of tritiated OT-101 into Sprague-Dawley CD (albino) rats. Throughout the studies, there were no sex differences. After 1 hr intracerebral infusion in rats, OT-101 was limited to the infusion site. Whereas for the 1 hr itravesicular infusion, OT-101 was more widespread with 35X, 19X, 12X higher concentration found in cerebellum, remaining cerebrum, cerebrospinal fluid (CSF), respectively. OT-101 concentration was stable for the first 4 hours post infusion and decayed biexponentially with a slow terminal half life for tissue but not for CSF, suggestive of rapid penetration of the underlying tissue away from the CSF compartment. Minimum amount of OT-101 was detected in the plasma compartment. Intrathecal bolus administration of 0.1mL of OT-101 at 14, 30, 200, 300, and 500 uM into cynomolgus monkies did not result in any single dose toxicity. Histopathology examination revealed no substance-related histomorphological lesions in the cavum subarachnoideale of the lumbar region. No changes were noted in the grey and white matter of the spinal cord, the nerve trunk, and nerve cells did not show any abnormalities. These data suggest that intrathecal administration of OT-101 is a potentially effective delivery route for antisense therapeutics such as OT-101 to the midline ie. for Diffuse Midline Glioma (DMG). A phase 1b/2 clinical trial evaluating OT-101 against DMG is proposed and the trial design will be presented

Gelsemine relieves the neuropathic pain by down-regulating DPP4 level in rats

BackgroundBased on the previous findings on the relieving role of gelsemine in neuropathic pain, this research aims to further investigate the relevant regulatory mechanism. MethodsTargets of gelsemine were predicted using SwissTargetPrediction. The peripheral neuropathic pain rat model was established by ligating spinal nerves, and then gelsemine (10 μg for one day) or dipeptidyl peptidase 4 (DPP4) oligonucleotides (5 μg/day, for 7 days) was injected into intrathecal bolus of rats. The mechanical threshold (0, 1, 2, 4 h after the last injection) was examined to evaluate the mechanical allodynia of rats. After the mechanical threshold measurement, the rats were anesthetized with isoflurane and then sacrificed by cervical dislocation. IBA1- and DPP4-positive cells in the spinal dorsal horn of rats were determined using immunohistochemistry and immunofluorescence assays. The expressions of DPP4, IL-1β and TNF-α in the spinal dorsal horn of rats were measured by Western blot and quantitative real-time PCR. ResultsDPP4 was one of the targets of gelsemine. Gelsemine could elevate the down-regulated mechanical threshold, and lessen the up-regulated IBA1- and DPP4-positive cells and expressions of DPP4, IL-1β and TNF-α in the spinal dorsal horn of rats with neuropathic pain. DPP4 overexpression reversed the role of gelsemine in neuropathic pain. ConclusionGelsemine relieves neuropathic pain by down-regulating DPP4 level in rats, providing a novel drug candidate and biomarker for neuropathic pain treatment.

Results of the first‐in‐human, randomized, double‐blind, placebo‐controlled phase 1b study of lumbar intrathecal bolus administrations of antisense oligonucleotide (ISIS 814907; BIIB080) targeting tau mRNA in patients with mild Alzheimer’s disease

AbstractBackgroundISIS 814907 (BIIB080) is an antisense oligonucleotide (ASO) that hybridizes to a complementary nucleotide sequence of mRNA of the human microtubule‐associated protein tau (MAPT) gene, preventing production of tau protein. Accumulation of hyperphosphorylated tau is associated with cognitive decline and brain atrophy in Alzheimer’s Disease (AD). The placebo controlled period of the Phase 1b multiple ascending dose (MAD) study of ISIS 814907 in patients with mild AD is complete and the open‐label long term extension (LTE) is ongoing in the UK, Canada, Germany, Sweden, Netherlands and Finland (EudraCT: 2016‐002713‐22; NCT03186989).MethodsThe study is divided into 2 parts. Part 1 is the MAD study, comprising a 3‐month Treatment Evaluation (TE) Period and a 6‐month Post‐Treatment (PT) Period. Part 2 is the open‐label LTE, comprising a 12‐month TE Period and a 4‐ or 6‐month PT Period. Four ascending dose cohorts were enrolled sequentially and randomized 3:1 to intrathecal (IT) bolus administrations of ISIS 814907 or placebo. Male or female patients aged 50‐74 years with mild AD and confirmed amyloid positivity (via CSF) at Screening were considered eligible. The primary objective was to assess safety and tolerability of multiple IT bolus administrations of ISIS 814907. The secondary objective was to evaluate CSF pharmacokinetics (PK). Exploratory objectives include assessment of plasma PK, target engagement and disease biomarkers, genotype and clinical endpoints relevant to AD.ResultsAll subjects (N=46) completed the MAD TE Period and 43 subjects completed the PT Period. All AEs were mild/moderate in severity. No serious AEs occurred in subjects receiving ISIS 814907. Dose‐dependent mean reduction from baseline in CSF total tau and phospho‐tau was observed in the TE period and continued in the PT period. CSF total tau and phospho‐tau reductions were comparable.ConclusionsIT bolus administration of multiple ascending doses of ISIS 814907 over 3 months was well‐tolerated in patients with mild AD. The robust lowering of CSF total tau and phospho‐tau warrants further investigation for the treatment of AD.

Pilot Study Assessing the Impact of Intrathecal Administration of Variants AAV-PHP.B and AAV-PHP.eB on Brain Transduction in Adult Rhesus Macaques.

Adeno-associated virus (AAV) vectors are increasingly used as an effective and safe approach to deliver genetic material to the central nervous system (CNS). The AAV9-derived variants, AAV-PHP. B and AAV-PHP.eB, reportedly broadly transduce cells throughout the CNS compared to the original serotype 9, AAV9. As non-human primate data are scarce, we here evaluated the CNS transduction efficiencies after lumbar intrathecal bolus delivery of identical doses of either AAV-PHP. B:CAG-EGFP or AAV-PHP. eB:CAG-EGFP in rhesus macaque monkeys. AAV-PHP.eB achieved a more efficient and widespread CNS transduction compared to AAV-PHP.B. We report a strong neuronal and oligodendroglial tropism for both variants in the putamen and in the hippocampus. This proof-of-concept experiment highlights the potential value of intrathecal infusions of AAV-PHP.eB to distribute genetic material in the CNS with cell-type specificity and introduces a new opportunity to model brain diseases in rhesus macaque monkeys and further develop gene therapies targeting the CNS in humans.

Short-Term Outcomes of a High-Volume, Low-Concentration Bolus Starting Dose Technique With Ziconotide: A Case Series

Background and ObjectivesThere have been numerous recommendations for a starting dose of intrathecal ziconotide. The therapy remains underutilized partially due to reports of inefficacy and/or intolerance. This study describes short‐term outcomes of a high‐volume, low‐concentration bolus (HVLC‐B) ziconotide starting dose technique for patients with chronic spine pain. Intrathecal pumps are available with a Patient Therapy Manager (PTM), or patient‐controlled intrathecal bolus device. Commonly published recommendations for a bolus dose has been 10% of the daily dose. This article describes an inversion of the traditional 10% rule‐of‐thumb. This article describes using the basal rate at a lowest programmable dose and utilizing the bolus for the majority of the medication delivery. Such an inversion may be considered a high volume bolus. The lowest commercially available concentration of ziconotide from the manufacturer is 25 mcg/mL. Pope and Deer (Neuromodulation, 18, 414–420 [2015]) described use of a dilution down to 5 mcg/mL. For purposes of this article, such dilutions to one‐fifth of the commercially available solution are considered sufficiently dilute to qualify for the term “low concentration.” Furthermore, the patients in this analysis received dilutions down to one‐fiftieth of the lowest commercially available solution.Materials and MethodsA case series of patients with chronic spine pain with or without radicular pain received a starting dose intrathecal ziconotide regimen based on a specific HVLC‐B technique. Efficacy, tolerability, and pump settings are reported and analyzed.ResultsIn total, 17 patients were identified who started ziconotide with the specified HVLC‐B starting regimen. One of the 17 patients reported side effects that led to discontinuation of the therapy, although the side effect was not typical of ziconotide but rather likely attributable to other medications the patient was taking. Fifteen of the 17 reported improved pain control with intrathecal ziconotide. Sixteen of the 17 patients remained on intrathecal ziconotide throughout the 4.7‐month average follow‐up period. One patient who failed to obtain pain relief chose to remain on the therapy because of reported resolution of lower limb numbness.ConclusionsThe HVLC‐B starting regimen was effective and well tolerated in this short‐term study of patients with chronic spine pain. More studies are needed to better elucidate long‐term outcomes in larger patient populations.

A Case of Priapism After Intrathecal Morphine Injection

BACKGROUND: Data on the frequency of priapism after spinal injections is lacking. Priapism may occur as a rare complication following intrathecal narcotic administration. This report describes an uncommon adverse reaction to intrathecal morphine injection uniquely without concurrent local anesthetic. CASE REPORT: A 74-year-old male presented to the pain management office for a scheduled intrathecal bolus trial to monitor for response prior to permanent placement of an intrathecal pump. Following an intrathecal injection of a bolus dose of 100 mcg of morphine, the patient noted the development of an erection lasting 8 hours. A diagnosis of intrathecal morphine-induced priapism was made. CONCLUSION: This report presents the first case in the literature of priapism induced by noncontinuous intrathecal morphine injection in the context of an intrathecal pump trial. A specific mechanism has not yet been defined; however, we believe multiple factors play a role in the body’s response to morphine. KEY WORDS: Case report, chronic pain, intrathecal drug delivery, morphine, priapism

The inflammatory profile of cerebrospinal fluid, plasma, and saliva from patients with severe neuropathic pain and healthy controls-a pilot study

BackgroundNeuropathic pain (NeuP) is a complex, debilitating condition of the somatosensory system, where dysregulation between pro- and anti-inflammatory cytokines and chemokines are believed to play a pivotal role. As of date, there is no ubiquitously accepted diagnostic test for NeuP and current therapeutic interventions are lacking in efficacy. The aim of this study was to investigate the ability of three biofluids - saliva, plasma, and cerebrospinal fluid (CSF), to discriminate an inflammatory profile at a central, systemic, and peripheral level in NeuP patients compared to healthy controls.MethodsThe concentrations of 71 cytokines, chemokines and growth factors in saliva, plasma, and CSF samples from 13 patients with peripheral NeuP and 13 healthy controls were analyzed using a multiplex-immunoassay based on an electrochemiluminescent detection method. The NeuP patients were recruited from a clinical trial of intrathecal bolus injection of ziconotide (ClinicalTrials.gov identifier NCT01373983). Multivariate data analysis (principal component analysis and orthogonal partial least square regression) was used to identify proteins significant for group discrimination and protein correlation to pain intensity. Proteins with variable influence of projection (VIP) value higher than 1 (combined with the jack-knifed confidence intervals in the coefficients plot not including zero) were considered significant.ResultsWe found 17 cytokines/chemokines that were significantly up- or down-regulated in NeuP patients compared to healthy controls. Of these 17 proteins, 8 were from saliva, 7 from plasma, and 2 from CSF samples. The correlation analysis showed that the most important proteins that correlated to pain intensity were found in plasma (VIP > 1).ConclusionsInvestigation of the inflammatory profile of NeuP showed that most of the significant proteins for group separation were found in the less invasive biofluids of saliva and plasma. Within the NeuP patient group it was also seen that proteins in plasma had the highest correlation to pain intensity. These preliminary results indicate a potential for further biomarker research in the more easily accessible biofluids of saliva and plasma for chronic peripheral neuropathic pain where a combination of YKL-40 and MIP-1α in saliva might be of special interest for future studies that also include other non-neuropathic pain states.

Save Your Maximum Tolerated Dose: How to Diagnose Procedure-Related Spinal Cord Lesions After Lumbar Intrathecal Bolus Administration of Oligonucleotides in Cynomolgus Monkeys.

Many potential drugs for treatment of neurodegenerative diseases, particularly antisense oligonucleotides (ASOs), are administered via lumbar intrathecal injection, because these drugs do not cross the blood-brain barrier. Intrathecal injection is a well-established method in cynomolgus monkeys, a species that is used in preclinical safety assessment when other nonrodent species cannot be used. The authors completed intrathecal ASO administration in over 30 preclinical safety studies (>1000 animals and >4500 dose administrations) during which we observed 3 cases of procedure-related spinal cord necrosis (incidence <0.1%). We describe clinical symptoms, diagnostic approaches, morphological features, and prognosis of this rare injury, and compare these findings with typical drug-related findings of ASOs dosed by intrathecal injection. The low incidence of procedure-related and dose-limiting lesions confines this analysis to a small sample set. The pattern of effects is similar across all monkeys despite differences in age, body weight, and intrathecal injection site. All 3 cases presented a combination of the following findings: blood in cerebrospinal fluid at time of injection, clinical signs that increase in severity within a day of dosing, lameness of both hind limbs, reduced muscle tone, and loss of patellar, foot grip, and/or anal reflexes. In all cases, magnetic resonance imaging (MRI) showed a linear hyperintense lesion in the lumbar spinal cord. In 2 cases, this hyperintensity was associated with evidence of spinal cord edema. We conclude that a pattern of in-life and pathology findings, including noninvasive MRI assessment, is indicative of procedure-related effects.

Range of Neurological Signs in Cynomolgus Monkeys After Intrathecal Bolus Administration of Antisense Oligonucleotides.

Intrathecal (IT) dosing (ie, injection into the subarachnoidal space at the lumbar region) is a common route of administration in cynomolgus monkey preclinical safety studies conducted for antisense oligonucleotides (ASO) that target central nervous system diseases. Herein we report on neurological signs that have been observed in 28 IT studies conducted in 1,016 cynomolgus monkeys. Neurological signs were classified into 5 groups: (1) A nonadverse transient absence of lower spinal reflexes. This observation occurred at low incidence in nontreated animals and in those that were injected artificial cerebrospinal fluid. The incidence increased in animals that were injected an ASO. Reflexes were present again at 24 hours or 48 hours after dosing. The incidence appeared to increase with dose. (2) Test-article-related adverse muscle tremor or muscle spasticity occurring during the injection procedure or immediately thereafter. In one-third of animals this finding responded to treatment with diazepam, in two-third it required euthanasia. (3) Neurological findings occurring between 30 minutes and 4 hours after dosing were characterized by any combination of ataxia, paresis, nystagmus, urinary incontinence, or muscle tremor. Those conditions either spontaneously resolved or they slowly worsened, eventually resulting in a poor general condition. (4) Neurological findings due to spinal cord injury were characterized by rapidly progressing paralysis of hind limbs. Magnetic resonance imaging revealed a focal hyperintense lesion, indicative of spinal cord necrosis. (5) Test-article-related adverse hind limb paresis or paralysis that occurred between 2 and 18 days after dosing. Those findings were rare and resulted in a poor general condition requiring euthanasia.

Brain pharmacology of intrathecal antisense oligonucleotides revealed through multimodal imaging.

Intrathecal (IT) delivery and pharmacology of antisense oligonucleotides (ASOs) for the CNS have been successfully developed to treat spinal muscular atrophy. However, ASO pharmacokinetic (PK) and pharmacodynamic (PD) properties remain poorly understood in the IT compartment. We applied multimodal imaging techniques to elucidate the IT PK and PD of unlabeled, radioactively labeled, or fluorescently labeled ASOs targeting ubiquitously expressed or neuron-specific RNAs. Following lumbar IT bolus injection in rats, all ASOs spread rostrally along the neuraxis, adhered to meninges, and were partially cleared to peripheral lymph nodes and kidneys. Rapid association with the pia and arterial walls preceded passage of ASOs across the glia limitans, along arterial intramural basement membranes, and along white-matter axonal bundles. Several neuronal and glial cell types accumulated ASOs over time, with evidence of probable glial accumulation preceding neuronal uptake. IT doses of anti-GluR1 and anti-Gabra1 ASOs markedly reduced the mRNA and protein levels of their respective neurotransmitter receptor protein targets by 2 weeks and anti-Gabra1 ASOs also reduced binding of the GABAA receptor PET ligand 18F-flumazenil in the brain over 4 weeks. Our multimodal imaging approaches elucidate multiple transport routes underlying the CNS distribution, clearance, and efficacy of IT-dosed ASOs.

Low-dose intrathecal naloxone to enhance intrathecal morphine analgesia: A case report

Ultra low doses of opioid antagonists such as naloxone block excitatory opioid receptor pathways may paradoxically enhance morphine analgesia. This case study reports safety and efficacy of ultra low-dose intrathecal (IT) naloxone added to IT morphine for the treatment of severe refractory chronic low back pain. A 56-year-old man with a history of severe chronic low back pain (post-laminectomy syndrome) was evaluated. Extensive multidisciplinary therapies had all failed. Initial treatment at our clinic was a lumbar IT trial of morphine (unsuccessful) up to 50 mg/day. We administered an IT bolus of morphine 2 mg combined with IT naloxone of 20 ng with the patient's consent and approval. The onset of pain relief was within 20 minutes and peaked at 1 hour with a 50 percent reduction in VAS pain score. There were no signs of adverse drug toxicity or hemodynamic compromise. An IT infusion of daily morphine 5 mg and naloxone 50 ng was started. Throughout the 3-year follow-up period, the patient maintained pain reduction of 60 to 80 percent, with a return to daily activities and no further hospitalizations.

Antisense oligonucleotides selectively suppress target RNA in nociceptive neurons of the pain system and can ameliorate mechanical pain.

There is an urgent need for better treatments for chronic pain, which affects more than 1 billion people worldwide. Antisense oligonucleotides (ASOs) have proven successful in treating children with spinal muscular atrophy, a severe infantile neurological disorder, and several ASOs are currently being tested in clinical trials for various neurological disorders. Here, we characterize the pharmacodynamic activity of ASOs in spinal cord and dorsal root ganglia (DRG), key tissues for pain signaling. We demonstrate that activity of ASOs lasts up to 2 months after a single intrathecal bolus dose. Interestingly, comparison of subcutaneous, intracerebroventricular, and intrathecal administration shows that DRGs are targetable by systemic and central delivery of ASOs, while target reduction in the spinal cord is achieved only after direct central delivery. Upon detailed characterization of ASO activity in individual cell populations in DRG, we observe robust target suppression in all neuronal populations, thereby establishing that ASOs are effective in the cell populations involved in pain propagation. Furthermore, we confirm that ASOs are selective and do not modulate basal pain sensation. We also demonstrate that ASOs targeting the sodium channel Nav1.7 induce sustained analgesia up to 4 weeks. Taken together, our findings support the idea that ASOs possess the required pharmacodynamic properties, along with a long duration of action beneficial for treating pain.

Efficacy of a Targeted Drug Delivery on-Demand Bolus Option for Chronic Pain.

Intrathecal targeted drug delivery systems historically required physician office visits for dose adjustment to manage fluctuating pain. A wireless device now enables patients to supplement their basal intrathecal infusion with a programmed on-demand bolus dose. We sought to quantify the change in oral breakthrough opioid need associated with the use of an intrathecal bolus in comparison to those treated with the basal infusion alone. Demographic, dosage, bolus usage and longevity data were extracted from the historical medical record of 69 patients (18/51 bolus/nonbolus) followed continuously at our center. Medication consumption and Pain Disability Index measures were obtained at baseline and most recent follow-up. Among patients with the bolus option, only 2 (11%; confidence interval [CI] 0% to 26%) continued to require oral opiates to manage breakthrough pain compared to 29 (57%; CI 43% to 71%) without the bolus option. The Pain Disability Index score decreased by 19% in patients with the bolus option and by 25% in those with the basal infusion. Total daily intrathecal opioid intake was 34% lower in the group with the bolus device. Utilizing an intrathecal bolus to treat incident pain was a safe way to manage unpredictable breakthrough pain and may represent a cost-saving opportunity by eliminating the need for oral analgesic medications.

Large Volume Intrathecal Bolus: CSF Pressure and Implications for Safety

ObjectivesLarge volume intrathecal (IT) bolus administrations yield an efficient method of therapeutic delivery to the cerebral CSF from a clinically accessible injection site. In non‐human primates, high volume bolus can translocate up to 90% of the administered substance to the cerebro‐cervical CSF immediately. It is known that administration of up to ca. 20% of the total CSF volume is safe for humans and monkeys; however, the safety parameters detailing the volume and underlying mechanistic limits have not been studied. The goal of the present work is to characterize the relationship between administered volumes and rates and intracranial pressure (ICP) as a safety parameter in rats and monkeys.MethodsICP was measured in the cisterna magna (rats) and the subcutaneous injection port leading to the lumbar CSF (monkeys) utilizing a 1F piezoresistive diffused semiconductor pressure sensor mounted at the tip of a 20 cm long 0.8 F polyimide catheter (Millar, Inc). Signal processing was carried out using a FE221 Bridge Amplifier coupled with a PowerLab 4/35 (ADInstruments). Control of both modules and waveform analysis was performed using LabChart 8 software (ADInstruments).ResultsICP in rats and monkeys was characterized by a periodic waveform of classical shape with spectrally resolved P1, P2, and P3 components (Fig. 1). Mean baseline ICP in rats was 9.3±2.3 mmHg. The adaptability of rats to varying ICPs was studied by plotting the time‐averaged amplitude of the P1 component against the mean ICP. Correlation between these two variables formed three distinctive zones: (1) low synchronization (good compensatory reserve) at low ICP, (2) good synchronization (poor compensatory reserve) at higher ICP, and (3) negative correlation (impaired compensatory mechanisms) at ICP &gt; 32.3±6.5 mmHg (Fig. 1). The determined terminally “critical” ICP was then used to ascertain safe infusion rates and volumes in a separate group of rats. We found that infusion rates of up to 40 mkL/min could be used to safely administer volumes of at least 50% of CSF volume, whereas significantly smaller volumes could be infused at higher rates (Fig. 2). Our previous studies showed that monkeys tolerated bolus injections of 0.5 mL/kg body weight given at ca. 2 mL/min. Administration of this volume in a group of N=4 resulted in an ICP elevation by 47.5±5.9 mmHg. In rats and monkeys, the elevated post‐bolus ICP exponentially relaxed to the baseline within 11.3±8.1 min and 12.3±8.1 min, respectively.ConclusionsICP is a function of the rate and volume of fluid administration in the CSF and can safely be tolerated up to 32.3±6.5 mmHg (3.5‐fold) in rats. Comparable ICP relaxation times in monkeys and rats suggest similarities in the mechanisms of volume accommodation (hydrostatic compliance in the cervical region) and ICP adaptation (likely accelerated CSF drainage). The obtained data can improve the prediction of the safety of large‐volume IT drug administration and can be instrumental for identifying mechanisms regulating ICP adaptability.Support or Funding InformationThis study was supported by MGH ECOR Formulaic Award (2015) and NIH grants R01NS092838 and R21NS090049.

295. Intrathecal Delivery of rAAV9-ABCD1 by Osmotic Pump in a Mouse Model of Adrenomyeloneuropathy

Adrenomyeloneuropathy (AMN) is a debilitating neurological disorder caused by mutations in the ABCD1 gene, which encodes a peroxisomal ATP-binding cassette transporter (ABCD1) responsible for transport of CoA-activated very long-chain fatty acids (VLCFA) into the peroxisome for degradation. The Abcd1-/- mouse develops a phenotype similar to AMN, manifesting spinal cord axon degeneration as well as peripheral neuropathy due to affected dorsal root ganglion neurons (DRGs). We previously reported successful transduction of central nervous system cells in vitro and in vivo using recombinant adeno-associated virus serotype 9 (rAAV9) vector for delivery of the human ABCD1 gene. Unfortunately, intravenous delivery in young mice was associated with cardiac toxicity due to transgene overexpression. We therefore set out to optimize delivery to the spinal cord while minimizing systemic leakage using an intrathecal osmotic pump. Self complementary AAV9 GFP(scAAV9GFP) and rAAV9 encoding ABCD1 (rAAV9-ABCD1) were delivered to Abcd1-/- mice intrathecally (IT) either by bolus over a 2min duration or by osmotic pump over 24h duration with PBS injection as sham control. Two weeks after injection, mice were sacrificed and perfused with 4% PFA. Tissues were then collected, sectioned and stained for immunofluorescence analysis. scAAV9-GFP delivered IT by osmotic pump led to widespread expression across CNS-relevant cell types and DRGs in a dose-dependent manner. Spinal cord and DRG had higher expression compared with brain, but GFP expression was also detected in peripheral organs (liver, heart and adrenal gland), with highest expression seen at 3X1011GC. A similar distribution pattern of ABCD1 protein was detected after rAAV9-ABCD1 intrathecal pump delivery. In general, higher doses (2X1011GC and 1X1011GC) led to more expression in CNS and peripheral organs compared with a lower dose (0.5X1011GC). However, widespread expression of ABCD1 across CNS was even detected after direct intrathecal bolus injection of 0.5X1011GC. Importantly, the same dose delivered by pump led to higher expression in brain and spinal cord far from the injection site and comparatively less leakage to peripheral organs compared with bolus injection. Preliminary experiments delivering rAAV9-ABCD1 at 0.5X1011GC by intracerebroventricular approach suggest behavioral improvement in the Abcd1-/- mouse despite localized expression in brain. We therefore anticipate even better performance at this dose using the outlined intrathecal pump delivery. We conclude that rAAV9-mediated ABCD1 gene transfer via intrathecal osmotic pump leads to more uniform and widespread gene delivery to CNS with reduced leakage into the systemic circulation compared with intrathecal bolus injection.