Boosting Antitumor Response by Costimulatory Strategies Driven to 4-1BB and OX40 T-cell Receptors.

Immunotherapy explores several strategies to enhance the host immune system's ability to detect and eliminate cancer cells. The use of antibodies that block immunological checkpoints, such as anti-programed death 1/programed death 1 ligand and cytotoxic T-lymphocyte-associated protein 4, is widely recognized to generate a long-lasting antitumor immune response in several types of cancer. Evidence indicates that the elimination of tumors by T cells is the key for tumor control. It is well known that costimulatory and coinhibitory pathways are critical regulators in the activation of T cells. Besides blocking checkpoints inhibitors, the agonistic signaling on costimulatory molecules also plays an important role in T-cell activation and antitumor response. Therefore, molecules driven to costimulatory pathways constitute promising targets in cancer therapy. The costimulation of tumor necrosis factor superfamily receptors on lymphocytes surface may transduce signals that control the survival, proliferation, differentiation, and effector functions of these immune cells. Among the members of the tumor necrosis factor receptor superfamily, there are 4-1BB and OX40. Several clinical studies have been carried out targeting these molecules, with agonist monoclonal antibodies, and preclinical studies exploring their ligands and other experimental approaches. In this review, we discuss functional aspects of 4-1BB and OX40 costimulation, as well as the progress of its application in immunotherapies.

Development of recombinant human granulocyte colony-stimulating factor (nartograstim) production process in Escherichia coli compatible with industrial scale and with no antibiotics in the culture medium.

The granulocyte colony-stimulating factor (G-CSF) is a hematopoietic cytokine that has important clinical applications for treating neutropenia. Nartograstim is a recombinant variant of human G-CSF. Nartograstim has been produced in Escherichia coli as inclusion bodies (IB) and presents higher stability and biological activity than the wild type of human G-CSF because of its mutations. We developed a production process of nartograstim in a 10-L bioreactor using auto-induction or chemically defined medium. After cell lysis, centrifugation, IB washing, and IB solubilization, the following three refolding methods were evaluated: diafiltration, dialysis, and direct dilution in two refolding buffers. Western blot and SDS-PAGE confirmed the identity of 18.8-kDa bands as nartograstim in both cultures. The auto-induction medium produced 1.17 g/L and chemically defined medium produced 0.95 g/L. The dilution method yielded the highest percentage of refolding (99%). After refolding, many contaminant proteins precipitated during pH adjustment to 5.2, increasing purity from 50 to 78%. After applying the supernatant to cation exchange chromatography (CEC), nartograstim recovery was low and the purity was 87%. However, when the refolding solution was applied to anion exchange chromatography followed by CEC, 91%-98% purity and 2.2% recovery were obtained. The purification process described in this work can be used to obtain nartograstim with high purity, structural integrity, and the expected biological activity. KEY POINTS: • Few papers report the final recovery of the purification process from inclusion bodies. • The process developed led to high purity and reasonable recovery compared to literature. • Nartograstim biological activity was demonstrated in mice using a neutropenia model.

Experience with Sorafenib in 3 Hospitals in Sao Paulo.

INTRODUCTION AND AIM: Sorafenib has been the standard of care for first-line treatment of advanced hepatocellular carcinoma, a complex disease that affects an extremely heterogenous population. Thereby requiring multidisciplinary individualized treatment strategies that match the disease characteristics and the patients' specific needs. MATERIAL AND METHODS: Data for 175 patients who received sorafenib for hepatocellular carcinoma in three different hospitals in Sao Paulo, Brazil over a span of nine years were retrospectively analyzed. RESULTS: The median age was 62 years. Percentages of patients with Child-Pugh A, B and C liver cirrhosis were 61%, 31% and 5%, respectively. Approximately half of the patients had Barcelona Clinic Liver Cancer stage B disease, and the other half had stage C. The median treatment duration was 253 days. Sorafenib dose was reduced to 400 mg/day in 41% of the patients due to toxicity. Overall objective response rate as per Response Evaluation Criteria in Solid Tumors and its modified version was 39%. Patients who received transarterial chemoembolization (TACE) at any point during sorafenib therapy were significantly more likely to experience an objective response. After a median follow-up of 339 days, the median overall survival was 380 days. Child-Pugh cirrhosis, tumor response and concomitant chemoembolization were independent prognostic factors for overall survival in multivariate analysis. CONCLUSION: Our results suggest that, in experienced hands, sorafenib therapy may benefit carefully selected hepatocellular carcinoma patients for whom other therapies are initially contraindicated, including those patients with Child-Pugh B liver function and those patients who are subsequently treated with concomitant TACE.