Phase I Trial of Arginine Deprivation Therapy with ADI-PEG 20 Plus Docetaxel in Patients with Advanced Malignant Solid Tumors

PURPOSE: This phase I study examined the toxicity and tolerability, of pegylated arginine deiminase (ADI-PEG 20) in combination with docetaxel in patients with advanced solid malignancies. EXPERIMENTAL DESIGN: Eligible patients had histologically proven advanced solid malignancies, with any number of prior therapies, zubrod performance status 0–2 and adequate organ function. Patients received ADI-PEG 20 weekly intramuscular injection ranging from 4.5–36 mg/m(2), and up to ten doses of docetaxel 75 mg/m(2) every three weeks. Primary endpoints were safety, toxicity and a recommended phase II dose. Circulating arginine levels were measured prior to each cycle. Tumor response was measured as a secondary endpoint every six weeks on study. RESULTS: Eighteen patients received a total of 116 cycles of therapy through four dose levels of ADI-PEG 20. A single dose-limiting toxicity (grade 3 urticarial rash) was observed at the 1(st) dose level, with no additional dose-limiting toxicities observed. Hematologic toxicities were common with 14 patients experiencing at least one grade 3–4 leukopenia. Fatigue was the most prevalent toxicity reported by 16 patients. Arginine was variably suppressed with ten patients achieving at least a 50% reduction in baseline values. In 14 patients with evaluable disease, four partial responses (including two patients with PSA response) were documented and seven patients had stable disease. CONCLUSIONS: ADI-PEG 20 demonstrated reasonable toxicity in combination with docetaxel. Promising clinical activity was noted and expansion cohorts are now accruing for both castrate resistant prostate cancer and non-small cell lung cancer at a recommended phase II dose of 36 mg/m(2)

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Heterologous Expression of Biosynthetic Gene Clusters from Marine Cyanobacteria

Cyanobacteria are prolific producers of natural products with diverse structures and biological activities. Natural products are important for drug discovery and some of those isolated from cyanobacteria were found to have activities against cancer cells and infectious disease, or to relieve minor pain as anti-inflammatory drugs. However, slow growth rates, resistance to genetic engineering, and low yields limit the thorough investigation of many of these secondary metabolites within their native organisms. In this study, we describe and demonstrate the successful heterologous production of two bioactive secondary metabolites from marine cyanobacteria, cryptomaldamide and columbamide, in Anabaena sp. PCC 7120. This work resulted in the development and validation of new genetic tools and methods for the heterologous expression of large biosynthetic gene clusters. These tools include cloning vectors for transformation associated recombination in yeast and a new engineered strain of Anabaena along with a CRISPR/cpf1-based system that enables genetic engineering of large biosynthetic gene clusters in both Synechococcus elongatus PCC 7942 or Anabaena. This study showed that Anabaena is a more suitable host than S. elongatus for the production of marine cyanobacterial natural products. The heterologous expression of these biosynthetic gene clusters from marine cyanobacteria represents a significant opportunity to produce valuable compounds at a larger scale and for the further study of the mechanisms involved in the synthesis of these compounds

Heterologous Expression of Biosynthetic Gene Clusters from Marine Cyanobacteria

Cyanobacteria are prolific producers of natural products with diverse structures and biological activities. Natural products are important for drug discovery and some of those isolated from cyanobacteria were found to have activities against cancer cells and infectious disease, or to relieve minor pain as anti-inflammatory drugs. However, slow growth rates, resistance to genetic engineering, and low yields limit the thorough investigation of many of these secondary metabolites within their native organisms. In this study, we describe and demonstrate the successful heterologous production of two bioactive secondary metabolites from marine cyanobacteria, cryptomaldamide and columbamide, in Anabaena sp. PCC 7120. This work resulted in the development and validation of new genetic tools and methods for the heterologous expression of large biosynthetic gene clusters. These tools include cloning vectors for transformation associated recombination in yeast and a new engineered strain of Anabaena along with a CRISPR/cpf1-based system that enables genetic engineering of large biosynthetic gene clusters in both Synechococcus elongatus PCC 7942 or Anabaena. This study showed that Anabaena is a more suitable host than S. elongatus for the production of marine cyanobacterial natural products. The heterologous expression of these biosynthetic gene clusters from marine cyanobacteria represents a significant opportunity to produce valuable compounds at a larger scale and for the further study of the mechanisms involved in the synthesis of these compounds

Phase I Trial of Arginine Deprivation Therapy with ADI-PEG 20 Plus Docetaxel in Patients with Advanced Malignant Solid Tumors.

PurposeThis phase I study examined the toxicity and tolerability of pegylated arginine deiminase (ADI-PEG 20) in combination with docetaxel in patients with advanced solid malignancies.Experimental designEligible patients had histologically proven advanced solid malignancies, with any number of prior therapies, Zubrod performance status 0-2, and adequate organ function. Patients received ADI-PEG 20 weekly intramuscular injection ranging from 4.5 to 36 mg/m(2) and up to 10 doses of docetaxel (75 mg/m(2)) every 3 weeks. Primary endpoints were safety, toxicity, and a recommended phase II dose. Circulating arginine levels were measured before each cycle. Tumor response was measured as a secondary endpoint every 6 weeks on study.ResultsEighteen patients received a total of 116 cycles of therapy through four dose levels of ADI-PEG 20. A single dose-limiting toxicity (grade 3 urticarial rash) was observed at the 1st dose level, with no additional dose-limiting toxicities observed. Hematologic toxicities were common with 14 patients experiencing at least one grade 3 to 4 leukopenia. Fatigue was the most prevalent toxicity reported by 16 patients. Arginine was variably suppressed with 10 patients achieving at least a 50% reduction in baseline values. In 14 patients with evaluable disease, four partial responses (including 2 patients with PSA response) were documented, and 7 patients had stable disease.ConclusionsADI-PEG 20 demonstrated reasonable toxicity in combination with docetaxel. Promising clinical activity was noted, and expansion cohorts are now accruing for both castrate-resistant prostate cancer and non-small cell lung cancer at a recommended phase II dose of 36 mg/m(2)

Phase I Trial of Arginine Deprivation Therapy with ADI-PEG 20 Plus Docetaxel in Patients with Advanced Malignant Solid Tumors.

PurposeThis phase I study examined the toxicity and tolerability of pegylated arginine deiminase (ADI-PEG 20) in combination with docetaxel in patients with advanced solid malignancies.Experimental designEligible patients had histologically proven advanced solid malignancies, with any number of prior therapies, Zubrod performance status 0-2, and adequate organ function. Patients received ADI-PEG 20 weekly intramuscular injection ranging from 4.5 to 36 mg/m(2) and up to 10 doses of docetaxel (75 mg/m(2)) every 3 weeks. Primary endpoints were safety, toxicity, and a recommended phase II dose. Circulating arginine levels were measured before each cycle. Tumor response was measured as a secondary endpoint every 6 weeks on study.ResultsEighteen patients received a total of 116 cycles of therapy through four dose levels of ADI-PEG 20. A single dose-limiting toxicity (grade 3 urticarial rash) was observed at the 1st dose level, with no additional dose-limiting toxicities observed. Hematologic toxicities were common with 14 patients experiencing at least one grade 3 to 4 leukopenia. Fatigue was the most prevalent toxicity reported by 16 patients. Arginine was variably suppressed with 10 patients achieving at least a 50% reduction in baseline values. In 14 patients with evaluable disease, four partial responses (including 2 patients with PSA response) were documented, and 7 patients had stable disease.ConclusionsADI-PEG 20 demonstrated reasonable toxicity in combination with docetaxel. Promising clinical activity was noted, and expansion cohorts are now accruing for both castrate-resistant prostate cancer and non-small cell lung cancer at a recommended phase II dose of 36 mg/m(2)