A prospective randomized multicenter phase I/II clinical trial to evaluate safety and efficacy of NOVOCART disk plus autologous disk chondrocyte transplantation in the treatment of nucleotomized and degenerative lumbar disks to avoid secondary disease: safety results of Phase I—a short report

The NDisc study is a non-confirmatory, prospective, multi-center, unmasked, randomized study with two phases aimed at gathering preliminary clinical information on NDisc plus and NDisc basic used in the repair of herniated disks. The objectives of Phase I were to develop a safety profile and to evaluate feasibility of NDplus. This report presents data from Phase I up to 6 weeks after transplantation (Visit 4). Eligible patients underwent baseline assessments, sequestrectomy, and postoperative assessment of Visit 2. After this initial surgery, all patients were randomized with a 1:1 allocation ratio to either NDplus ADCT or NDbasic. Patients with a lumbar disk herniation were classified according to the presence (ADD) or absence (HD) of a degenerative disk at the adjacent level by the investigators of the center. At Visit 3, patients underwent pre-implantation assessments, transplantation and post-transplantation assessments. A follow-up was performed at Visit 4. The visit plan is shown in Table 1 in more detail.

Twenty-four patients with a single-level lumbar herniated disk were recruited consecutively in three different centers. The N-Disc trial aimed to include patients with symptomatic lumbar disk herniation who failed adequate conservative or interventional treatment approaches in accordance with the guidelines of the German Society of Neurosurgery and the German Society of Orthopedics and Orthopedic Surgery. Additionally, an MRI determined disk herniation at the treatment level needed to correlate with the primary symptoms. To minimize confounding, patients with significant comorbidities were excluded from the study. Further inclusion criteria needed to be met: (1) no previous lumbar spine surgery; (2) age between 18 to 60 years; (3) proficient enough in the German language to understand the study; (4) no magnetic resonance imaging (MRI) documented associated lumbar disease such as lumbar spinal stenosis, spondylolisthesis, or fracture. If patients showed an extensive damage of the annulus fibrosus intraoperatively that may subsequently pose a significant greater risk of recurrence or non-containment of the injected material, they were excluded from the trial and randomization was not carried out. Written informed consent has been obtained from each patient.

Overall patient disposition and demographics, neurological, and functional status were documented. Serology of HIV, hepatitis, and Treponema pallidum were determined preoperatively. Laboratory values such as interleukine-6 (IL-6) and C-reactive protein (CRP) as safety parameters were evaluated. All laboratory values were classified as normal or abnormal according to the laboratories normal ranges. Systolic and diastolic blood pressure and pulse rate as vital signs were assessed. Adverse events (AE) and serious adverse events (SAE) were documented. The analysis of adverse events was focused on treatment emergent adverse events (TEAE). A TEAE or TESAE is any AE or SAE that occurs during or after implant. Frequency and percentage of TEAEs were summarized according to the primary system organ class and preferred term and tabulated by treatment group.

Preoperative MRI of the lumbar spine was performed in a standardized fashion on a 1.5-Tesla MRI scanner. The protocols included T1- und T2-weighted turbo spin echo sequences in sagittal and transversal planes, a sagittal STIR sequence, a sagittal thin slice double echo volumetry sequence, and a sagittal spin echo T2 multi-echo relaxometry sequence, additionally. Numerical and comparative measurements in disk height, volumetry, and T2 relaxations times of index and adjacent disks and categorial evaluation such as degeneration scale, and the presence or absence of stenosis were determined by MRI. Osteochondrosis was graded by Modic changes [13]. The sequences were time optimized to improve patient’s acceptance and enable integrability of study protocols in the local MRI schedules. Furthermore, an external institution (MEDIRI—medical imaging research institute, Heidelberg, Germany) adapted the protocol to the local scanners to arrange image data comparability between the different study centers. Additionally, the institution trained local radiographers in standardized performance and engineered a software for central image processing and analysis. All images were read by an independent radiologist with high-level experience in spine imaging, blinded to patients and time of image acquisition.

The NDisc trial is an ongoing study of which Phase I safety results are presented here. Ethics approval was attained in Germany at the National Physician Board, “Landesärztekammer” Sachsen-Anhalt and in Austria at the committee of the Medical University Innsbruck. Furthermore, the clinical trial approval was obtained at the Paul-Ehrlich-Institute (Langen, Germany) and the Austrian Agency for Health and Food Safety (Vienna, Austria). The study complies with the World Medical Association Declaration of Helsinki Ethical Principles for Medical Research Involving Human Subjects, Good Clinical Practice (GCP), national pharmaceutical acts in the participating countries Austria and Germany, and European guidelines for the conduct of clinical trials with medicinal products for human use. The trial is initiated and sponsored by TETEC Ag (B|Braun Aesculap AG shared company, Reutlingen, Germany), which is responsible for management and registration (EudraCT No: 2010-023830-22, ID NCT01640457). CenTrial GmbH (Tuebingen, Germany) is responsible for clinical trial submission, independent clinical monitoring, and pharmacovigilance. Mediri GmbH (Heidelberg, Germany) as a core imaging lab is responsible for the development of MRI protocols, data storage, and analyses. Laboratory values are investigated centrally by Synlab Services GmbH (Synlab MVZ, Leinfelden-Echterdingen, Germany). Accovion GmbH (Eschborn, Germany) is responsible for data management, biometrics, and medial writing. Quality audits were performed routinely by the Ministry of Health.

NDisc plus is used for ADCT. NDisc plus is an injectable, in situ polymerizing gel initially consisting of two separate components. Component A is a liquid matrix composed of the cell culture medium, modified albumin, and hyaluronic acid. Component A also contains autologous inter-vertebral disk cells dissolved in cell culture medium supplemented with human serum, chondroitin sulfate, insulin, BMP-2, and ascorbate. Component B is a solution containing bis thio-polyethylene glycol. Component A and B polymerize in situ using a dedicated application system (special dual-chamber syringe) to form the desired hydrogel. NDisc basic is used as control in the NDisc study. In NDisc basic component A is a liquid matrix composed of cell culture medium, modified albumin, and hyaluronic acid, the cell suspension is replaced by an aliquot of cell culture medium without additives. Component B is not modified [14].

Surgery was performed by two trial-designated surgeons under general endotracheal anesthesia with the assistance of an operating microscope while the patient was in a prone position. Depending on the location of disk herniation, the spinal canal harboring the sequestrated disk material was exposed either by a minimal interlaminar fenestration or a translaminar approach. If intradiscal material had to be removed, a limited nucleotomy was also performed [15]. In case of a lateral lumbar herniation, a lateral extraforaminal approach was performed [16]. Right after the extraction of the disk tissue, it was transferred into a sterile transport vial and provided to TETEC AG for the GMP compliant manufacturing of the investigational medicinal product NDisc plus.

Transplantation was performed 90 days after sequestrectomy. NDplus or NDbasic was applied via an injection with a dual-needle technique directly at the intended site of action. NDplus or NDbasic is to be transplanted in a comfortable lateral or abdominal position. After the treatment level is localized and local anesthesia is applied, the puncture of the intervertebral disk was taken contra-laterally to the side of the disk surgery. An injection needle was placed in the center of the disk space under image guidance and the medicinal product was injected. In case of an ADD, the same procedure described above was conducted additionally at the adjacent, proximally located disk. Positioning of the needles and the mandarin took place simultaneously to minimize radiation exposure [14].

This is a non-confirmatory study without pre-specified decision-making rules or hypotheses. Except laboratory values, all statistical analyses are descriptive and exploratory and there was no adjustment of significance levels for multiple testing or interim analyses. For laboratory values, the Kolmogorov-Smirnov test was used for testing normal distribution. The unpaired Student’s t test, Mann-Whitney U test and Fisher’s exact test were used to analyze differences in laboratory values as applicable. A P value <0.05 was considered statistically significant. For CRP, values below detection levels (<0.02 mg/dL) were set to 0.02 and for IL-6, values below detection levels (<2.0 pg/mL) were set to 2.0. All values were expressed as mean ± SD. All results were presented by treatment group (NDplus and NDbasic). All data were pooled across study centers for analysis and safety evaluations for all subgroups or categories were also performed by pooling ADD and HD patients. Figures were designed using GraphPad Prism (version 5.0 for Mac OS X, GraphPad Software, La Jolla California USA, www.graphpad.com ).