The authors describe the first clinical trial with encapsulated cell biodelivery (ECB) implants that deliver nerve growth factor (NGF) to the cholinergic basal forebrain with the intention of halting the degeneration of cholinergic neurons and the associated cognitive decline in patients with Alzheimer disease (AD). The NsG0202 implant (NsGene A/S) consists of an NGF-producing, genetically engineered human cell line encapsulated behind a semipermeable hollow fiber membrane that allows the influx of nutrients and the efflux of NGF. The centimeter-long capsule is attached to an inert polymer tether that is used to guide the capsule to the target via stereotactic techniques and is anchored to the skull at the bur hole.
Six patients with mild to moderate AD were included in this Phase Ib open-label safety study and were divided into 2 dose cohorts. The first cohort of 3 patients received single implants targeting the basal nucleus of Meynert (Ch4 region) bilaterally (2 implants per patient), and after a safety evaluation, a second cohort of 3 patients received bilateral implants (a total of 4 implants per patient) targeting both the Ch4 region and the vertical limb of the diagonal band of Broca (Ch2 region). Stereotactic implantation of the devices was successfully accomplished in all patients. Despite extensive brain atrophy, all targets could be reached without traversing sulci, the insula, or lateral ventricles.
Postoperative CT scans allowed visualization of the barium-impregnated tethers, and fusion of the scans with stereotactic MR images scan was used to verify the intended positions of the implants. Follow-up MRI at 3 and 12 months postimplantation showed no evidence of inflammation or device displacement. At 12 months, implants were successfully retrieved, and low but persistent NGF secretion was detected in half of the patients.
With refinement, the ECB technology is positioned to become an important therapeutic platform in restorative neurosurgery and, in combination with other therapeutic factors, may be relevant for the treatment of a variety of neurological disorders. Clinical trial registration no.: NCT01163825.
"In a small pilot clinical study, nerve growth factor(NGF)-overexpressing immortalized human pigment epithelial cells were stereotactically delivered to the basal forebrain in retrievable encapsulation devices (Wahlberg et al., 2012). This work followed from studies demonstrating robust long-term NGF delivery in Gottinberg minipigs (Fjord-Larsen et al., 2010), though lower survival of the encapsulated cells was seen after retrieval of the devices from human brains (Wahlberg et al., 2012). Preliminary clinical results demonstrated less brain shrinkage than expected based on historical MMSE-matched controls in a subset of patients (Ferreira et al., 2015), though results at this point should be considered very preliminary. "
"All patients were treated with cholinesterase inhibitors (ChEI) for a mean duration of 15 6 7 months at study start, and continued on the same dose throughout the study. Three patients received single EC-NGF implants targeting the basal nucleus of Meynert (Ch4 region) bilaterally (i.e., two implants per patient), and three patients received double bilateral implants (a total of four implants per patient ) targeting both the Ch4 region and the vertical limb of the diagonal band of Broca (Ch2 region)  . This study was conducted according to the Declaration of Helsinki and subsequent revisions. "
[Show abstract][Hide abstract] ABSTRACT: Background: Extensive loss of central cholinergic functions in AD brain is linked to impaired nerve growth factor (NGF) signaling. The cardinal cholinergic biomarker is the acetylcholine synthesizing enzyme, choline acetyltransferase (ChAT), which has recently been found in cerebrospinal fluid (CSF).Method: Encapsulated cell implants releasing NGF (EC-NGF) were surgically implanted bilaterally in the basal forebrain of six AD patients for 12 months and cholinergic markers in CSF were analyzed. Hypothesis: EC-NGF therapy will alter CSF levels of cholinergic biomarkers, ChAT and acetylcholinesteraseResult: Activities of both enzymes were altered after 12 months. In particular, activity of soluble ChAT showed high correlation with cognition, CSF tau and amyloid-β, in vivo cerebral glucose utilization and nicotinic binding sites, as well as morphometric and volumetric MRI measures.Conclusion: A clear pattern of associations is demonstrated showing a proof-of-principle effect on CSF cholinergic markers, suggestive of a beneficial EC-NGF implant therapy
Alzheimer's and Dementia 11/2014; In-press. DOI:10.1016/j.jalz.2014.11.008 · 12.41 Impact Factor
"In clinical trials, the CNTF secreting capsule has shown positive safety profile and stable production of the therapeutic protein for over 2 years   . Also the NGF producing cell capsule has shown promising results, but further refinement of the technology is needed . For clinical suitability of this cell encapsulation system, the therapeutic protein is not expected to be a concern; the sVEGFR1 protein from human ARPE-19 cells should not cause immunological problems. "
[Show abstract][Hide abstract] ABSTRACT: Anti-angiogenic therapies with vascular endothelial growth factor (VEGF) inhibiting factors are effective treatment options for neovascular diseases of the retina, but these proteins can only be delivered as intravitreal (IVT) injections. To sustain a therapeutic drug level in the retina, VEGF inhibitors have to be delivered frequently, every 4–8 weeks, causing inconvenience for the patients and expenses for the healthcare system. The aim of this study was to investigate cell encapsulation as a delivery system for prolonged anti-angiogenic treatment of retinal neovascularization. Genetically engineered ARPE-19 cells secreting soluble vascular endothelial growth factor receptor 1 (sVEGFR1) were encapsulated in a hydrogel of cross-linked collagen and interpenetrating hyaluronic acid (HA). The system was optimized in terms of matrix composition and cell density, and long-term cell viability and protein secretion measurements were performed. sVEGFR1 ARPE-19 cells in the optimized hydrogel remained viable and secreted sVEGFR1 at a constant rate for at least 50 days. Based on pharmacokinetic/pharmacodynamic (PK/PD) modeling, delivery of sVEGFR1 from this cell encapsulation system is expected to lead only to modest VEGF inhibition, but improvements of the protein structure and/or secretion rate should result in strong and prolonged therapeutic effect. In conclusion, the hydrogel matrix herein supported the survival and protein secretion from the encapsulated cells. The PK/PD simulation is a convenient approach to predict the efficiency of the cell encapsulation system before in vivo experiments.
European Journal of Pharmaceutics and Biopharmaceutics 10/2014; DOI:10.1016/j.ejpb.2014.10.005 · 3.38 Impact Factor
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