Strategies for Setting Patient-Centric Commercial Specifications for Biotherapeutic Products

Commercial specifications for a new biotherapeutic product are a critical component of the product's overall control strategy that ensures safety and efficacy. This paper describes strategies for setting commercial specifications as proposed by a consortium of industry development scientists. The specifications for some attributes are guided by compendia and regulatory guidance. For other product quality attributes (PQAs), product knowledge and the understanding of attribute criticality built throughout product development should drive specification setting. The foundation of PQA knowledge is an understanding of potential patient impact through an assessment of potency, PK, immunogenicity and safety. In addition to PQA knowledge, the ability of the manufacturing process to consistently meet specifications, typically assessed through statistical analyses, is an important consideration in the specification-setting process. Setting acceptance criteria that are unnecessarily narrow can impact the ability to supply product or prohibit consideration of future convenient dosage forms. Patient-centric specifications enable appropriate control over higher risk PQAs to ensure product quality for the patient, and flexibility for lower risk PQAs for a sustainable supply chain. This paper captures common strategic approaches for setting specifications for standard biotherapeutic products such as monoclonal antibodies and includes considerations for ensuring specifications are patient centric.

Autologous stem cell therapy in the treatment of limb ischaemia induced chronic tissue ulcers of diabetic foot patients

BACKGROUND AND AIM

Despite improvements in surgical revascularisation, limitations like anatomical factors or atherosclerosis limit the success of revascularisation in diabetic patients with critical limb ischaemia. Stem cells were shown to improve microcirculation in published studies. The aim of this study was to evaluate safety, feasibility and efficacy of transplantation of bone marrow derived cellular products regarding improvement in microcirculation and lowering of amputation rate.

METHODS

Bone marrow mononuclear cells (BMCs) in comparison with expanded bone marrow cells enriched in CD90+ cells ('tissue repair cells', TRCs) were used in the treatment of diabetic ulcers to induce revascularisation. Diabetic foot patients with critical limb ischaemia without option for surgical or interventional revascularisation were eligible. Parameters examined were ABI, TcPO(2) , reactive hyperaemia and angiographic imaging before and after therapy.

RESULTS

Of 30 patients included in this trial, 24 were randomised to receive either BMCs or TRCs. The high number of drop-outs in the control group (4 of 6) led to exclusion from evaluation. A total of 22 patients entered treatment; one patient in the TRC group and two in the BMC group did not show wound healing during follow up, one patient in each treatment group died before reaching the end of the study; one after having achieved wound healing (BMC group), the other one without having achieved wound healing (TRC group). Thus, 18 patients showed wound healing after 45 weeks. The total number of applicated cells was 3.8 times lower in the TRC group, but TRC patients received significantly higher amounts of CD90+ cells. Improvement in microvascularisation was detected in some, but not all patients by angiography, TcPO(2) improved significantly compared with baseline in both therapy groups.

CONCLUSION

The transplantation of BMCs as well as TRCs proved to be safe and feasible. Improvements of microcirculation and complete wound healing were observed in the transplant groups.

Good manufacturing practice-compliant expansion of marrow-derived stem and progenitor cells for cell therapy

Ex vivo expansion is being used to increase the number of stem and progenitor cells for autologous cell therapy. Initiation of pivotal clinical trials testing the efficacy of these cells for tissue repair has been hampered by the challenge of assuring safe and high-quality cell production. A strategy is described here for clinical-scale expansion of bone marrow (BM)-derived stem cells within a mixed cell population in a completely closed process from cell collection through postculture processing using sterile connectable devices. Human BM mononuclear cells (BMMNC) were isolated, cultured for 12 days, and washed postharvest using either standard open procedures in laminar flow hoods or using automated closed systems. Conditions for these studies were similar to long-term BM cultures in which hematopoietic and stromal components are cultured together. Expansion of marrow-derived stem and progenitor cells was then assessed. Cell yield, number of colony forming units (CFU), phenotype, stability, and multilineage differentiation capacity were compared from the single pass perfusion bioreactor and standard flask cultures. Purification of BMMNC using a closed Ficoll gradient process led to depletion of 98% erythrocytes and 87% granulocytes, compared to 100% and 70%, respectively, for manual processing. After closed system culture, mesenchymal progenitors, measured as CD105+CD166+CD14-CD45- and fibroblastic CFU, expanded 317- and 364-fold, respectively, while CD34+ hematopoietic progenitors were depleted 10-fold compared to starting BMMNC. Cultured cells exhibited multilineage differentiation by displaying adipogenic, osteogenic, and endothelial characteristics in vitro. No significant difference was observed between manual and bioreactor cultures. Automated culture and washing of the cell product resulted in 181 x 10(6) total cells that were viable and contained fibroblastic CFU for at least 24 h of storage. A combination of closed, automated technologies enabled production of good manufacturing practice (GMP)-compliant cell therapeutics, ready for use within a clinical setting, with minimal risk of microbial contamination.

Wound therapy with autologous bone marrow stem cells in diabetic patients with ischaemia-induced tissue ulcers affecting the lower limbs

Previous studies suggest that autologous transplantation of bone marrow mononuclear cells is safe and effective in inducing therapeutic angiogenesis in patients with peripheral arterial occlusive disease (PAOD). Here we discuss a multidisciplinary approach to treating PAOD with a focus on the use of angiological diagnostic tools. We conclude that our autologous stem cell therapy is working in this patient and it is a potential new therapeutic option for diabetic patients with chronic foot ulcers induced by critical limb ischaemia.

Toxoplasma gondii eukaryotic translation initiation factor 4A associated with tachyzoite virulence is down-regulated in the bradyzoite stage

Comparative proteome analysis of mouse-virulent and attenuated Toxoplasma gondii strain revealed that steady-state synthesis of an unknown 53 kDa protein is markedly reduced in attenuated parasites. The results from protein microsequencing allowed isolation of a single-copy gene encoding a T. gondii homologue of eukaryotic translation initiation factor (eIF)4A. The deduced primary structure exhibits all sequence motifs typical of eIF4A. Differential expression of eIF4A between virulent and attenuated parasites was reconfirmed by immunoblot. Consistent with an involvement in the ribosomal preinitiation complex, the protein was localised in the tachyzoite extranuclear cytosol, being loosely associated with microsomal particles. Immunofluorescence detection of eIF4A in T. gondii stages of the intermediate host indicated that the protein is tachyzoite-specific. Stage-dependent expression is regulated at the transcriptional level as determined by reverse transcription-polymerase chain reaction and immunoblot. The down-regulation of eIF4A in attenuated T. gondii parasites and in the bradyzoite stage implies a role in tuning of the homeostasis of protein biosynthesis.