Safety and Efficacy in Advanced Solid Tumors of a Targeted Nanocomplex Carrying the p53 Gene Used in Combination with Docetaxel: A Phase 1b Study.

Loss of p53 suppressor function, through mutations or inactivation of the p53 pathway, occurs in most human cancers. SGT-53 is a liposomal nanocomplex designed for systemic, tumor-targeting delivery of the wt p53 gene. In this nanodelivery system, an anti-transferrin receptor single-chain antibody fragment serves as the targeting moiety. In an initial phase 1 trial in patients with advanced solid tumors, SGT-53 demonstrated tumor-specific targeting, was shown to be well tolerated, and was associated with an antitumor effect in several patients. Our preclinical studies have also demonstrated enhanced antitumor activity with the combination of SGT-53 and docetaxel. Thus, this dose-escalation trial was undertaken to assess the combination of SGT-53 and docetaxel for safety and potential efficacy in 14 advanced cancer patients. Results reveal that the combination of SGT-53 (maximum dose, 3.6 mg DNA/infusion) and docetaxel (75 mg/m(2)/infusion) was well tolerated. Moreover, clinical activity involving 12 evaluable patients was observed. Three of these patients achieved RECIST-verified partial responses with tumor reductions of -47%, -51%, and -79%. Two others had stable disease with significant shrinkage (-25% and -16%). These results support phase 2 testing of SGT-53 in combination with docetaxel.

Preclinical Justification of pbi-shRNA EWS/FLI1 Lipoplex (LPX) Treatment for Ewing's Sarcoma.

The EWS/FLI1 fusion gene is well characterized as a driver of Ewing's sarcoma. Bi-shRNA EWS/FLI1 is a functional plasmid DNA construct that transcribes both siRNA and miRNA-like effectors each of which targets the identical type 1 translocation junction region of the EWS/FLI1 transcribed mRNA sequence. Previous preclinical and clinical studies confirm the safety of this RNA interference platform technology and consistently demonstrate designated mRNA and protein target knockdown at greater than 90% efficiency. We initiated development of pbi-shRNA EWS/FLI1 lipoplex (LPX) for the treatment of type 1 Ewing's sarcoma. Clinical-grade plasmid was manufactured and both sequence and activity verified. Target protein and RNA knockdown of 85-92% was demonstrated in vitro in type 1 human Ewing's sarcoma tumor cell lines with the optimal bi-shRNA EWS/FLI1 plasmid. This functional plasmid was placed in a clinically tested, liposomal (LP) delivery vehicle followed by in vivo verification of activity. Type 1 Ewing's sarcoma xenograft modeling confirmed dose related safety and tumor response to pbi-shRNA EWS/FLI1 LPX. Toxicology studies in mini-pigs with doses comparable to the demonstrated in vivo efficacy dose resulted in transient fever, occasional limited hypertension at low- and high-dose assessment and transient liver enzyme elevation at high dose. These results provide the justification to initiate clinical testing.

Phase I study of a systemically delivered p53 nanoparticle in advanced solid tumors.

Selective delivery of therapeutic molecules to primary and metastatic tumors is optimal for effective cancer therapy. A liposomal nanodelivery complex (scL) for systemic, tumor-targeting delivery of anticancer therapeutics has been developed. scL employs an anti-transferrin receptor (TfR), scFv as the targeting molecule. Loss of p53 suppressor function, through mutations or inactivation of the p53 pathway, is present in most human cancers. Rather than being transiently permissive for tumor initiation, persistence of p53 dysfunction is a continuing requirement for maintaining tumor growth. Herein, we report results of a first-in-man Phase I clinical trial of restoration of the normal human tumor suppressor gene p53 using the scL nanocomplex (SGT-53). Minimal side effects were observed in this trial in patients with advanced solid tumors. Furthermore, the majority of patients demonstrated stable disease. One patient with adenoid cystic carcinoma had his status changed from unresectable to resectable after one treatment cycle. More significantly, we observed an accumulation of the transgene in metastatic tumors, but not in normal skin tissue, in a dose-related manner. These results show not only that systemically delivered SGT-53 is well tolerated and exhibits anticancer activity, but also supply evidence of targeted tumor delivery of SGT-53 to metastatic lesions.

Randomized Phase 2 Studies of Checkpoint Inhibitors Alone or in Combination With Pegilodecakin in Patients With Metastatic NSCLC (CYPRESS 1 and CYPRESS 2).

INTRODUCTION: Checkpoint inhibitors (CPIs) have been approved to treat metastatic NSCLC. Pegilodecakin + CPI suggested promising efficacy in phase 1 IVY, providing rationale for randomized phase 2 trials CYPRESS 1 and CYPRESS 2. METHODS: CYPRESS 1 (N = 101) and CYPRESS 2 (N = 52) included Eastern Cooperative Oncology Group performance status of 0 to 1 and first-line/second-line metastatic NSCLC, respectively, without known EGFR/ALK mutations. Patients were randomized 1:1; control arms received pembrolizumab (CYPRESS 1) or nivolumab (CYPRESS 2); experimental arms received pegilodecakin + CPI. Patients had programmed death-ligand 1 tumor proportion score of greater than or equal to 50% (CYPRESS 1) or 0% to 49% (CYPRESS 2). Primary end point was objective response rate (ORR) per investigator. Secondary end points included progression-free survival (PFS), overall survival (OS), and safety. Exploratory end points included immune activation biomarkers. RESULTS: Median follow-up for CYPRESS 1 and CYPRESS 2 was 10.0 and 11.6 months, respectively. Results for pegilodecakin + pembrolizumab versus pembrolizumab were as follows: ORR per investigator 47% versus 44% (OR = 1.1, 95% confidence interval [CI]: 0.5-2.5); median PFS 6.3 versus 6.1 months (hazard ratio [HR] = 0.937, 95% CI: 0.54-1.625); and median OS 16.3 months versus not reached (HR = 1.507, 95% CI: 0.708-3.209). Results per blinded independent central review were consistent. Treatment discontinuation rate owing to adverse events (AEs) doubled in the experimental arm (32% versus 15%). AEs with grade greater than or equal to 3 treatment-related AEs (62% versus 19%) included anemia (20% versus 0%) and thrombocytopenia (12% versus 2%). Results for pegilodecakin + nivolumab versus nivolumab were as follows: ORR per investigator 15% versus 12% (OR = 1.2, 95% CI: 0.3-5.9); median PFS 1.9 versus 1.9 months (HR = 1.006, 95% CI: 0.519-1.951); and median OS 6.7 versus 10.7 months (HR = 1.871, 95% CI: 0.772-4.532). AEs with grade greater than or equal to 3 treatment-related AEs (70.4% versus 16.7%) included anemia (40.7% versus 0%), fatigue (18% versus 0%), and thrombocytopenia (14.8% versus 0%). Biomarker data suggested activation of immunostimulatory signals of interleukin-10R pathway in pegilodecakin-containing arms. CONCLUSIONS: Despite evidence of biological effect in peripheral blood, adding pegilodecakin to CPI did not improve ORR, PFS, or OS, in first-line/second-line NSCLC. Pegilodecakin + CPI has been found to have overall higher toxicity compared with CPI alone, leading to doubling of treatment discontinuation rate owing to AEs.

Hereditary inclusion body myopathy: single patient response to GNE gene Lipoplex therapy.

BACKGROUND: Hereditary inclusion body myopathy (HIBM) is an autosomal recessive adult onset myopathy. It is characterized by mutations of the GNE (UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase) gene. Afflicted patients have no therapeutic options. In preclinical testing, we have previously demonstrated the ability to correct GNE gene function and the safety of delivery of wild type GNE gene using a liposomal delivery vehicle. METHODS: A single patient (subject #001) with severe HIBM treated by compassionate investigational new drug received four doses of GNE gene Lipoplex via intramuscular injection. GNE transgene expression, downstream induction of sialic acid, safety and muscle function were evaluated. RESULTS: Significant durable improvement in locoregional skeletal muscle function was observed in the injected left extensor carpi radialis longus of #001 in correlation with GNE transgene upregulation and local induction of sialic acid. Other than transient low grade fever and pain at the injection site, no significant toxicity was observed. CONCLUSIONS: Proof of principle for manufacturing of 'clinical grade' GNE gene Lipoplex, clinical safety and activity are demonstrated with GNE gene Lipoplex. Further assessment will involve intravenous administration and subsequent phase I trial involving additional but less severely afflicted HIBM patients.

Relationship of hypothyroidism and immune response to pegylated IL-10/nivolumab.

Aim: We describe a case of an advanced disease non-small-cell lung cancer patient with low PD-L1 expression, but high tumor mutation burden (35 muts/Mb) who developed immune-related hypothyroidism and achieved subsequent partial response, while on clinical trial (NCT03382912) with nivolumab and PEGylated IL-10 (Pegilodecakin, ARMO BioSciences/Eli Lilly and Company, IN, USA). Results/conclusion: Results suggest positive antitumor activity to combination IL-10/nivolumab despite low PD-L1 expression but in likely relationship to high tumor mutation burden and in association with immune-mediated thyroid dysfunction in this case.

A Randomized Phase II Trial of Epigenetic Priming with Guadecitabine and Carboplatin in Platinum-resistant, Recurrent Ovarian Cancer.

PURPOSE: Platinum resistance in ovarian cancer is associated with epigenetic modifications. Hypomethylating agents (HMA) have been studied as carboplatin resensitizing agents in ovarian cancer. This randomized phase II trial compared guadecitabine, a second-generation HMA, and carboplatin (G+C) against second-line chemotherapy in women with measurable or detectable platinum-resistant ovarian cancer. PATIENTS AND METHODS: Patients received either G+C (guadecitabine 30 mg/m2 s.c. once-daily for 5 days and carboplatin) or treatment of choice (TC; topotecan, pegylated liposomal doxorubicin, paclitaxel, or gemcitabine) in 28-day cycles until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were RECIST v1.1 and CA-125 response rate, 6-month PFS, and overall survival (OS). RESULTS: Of 100 patients treated, 51 received G+C and 49 received TC, of which 27 crossed over to G+C. The study did not meet its primary endpoint as the median PFS was not statistically different between arms (16.3 weeks vs. 9.1 weeks in the G+C and TC groups, respectively; P = 0.07). However, the 6-month PFS rate was significantly higher in the G+C group (37% vs. 11% in TC group; P = 0.003). The incidence of grade 3 or higher toxicity was similar in G+C and TC groups (51% and 49%, respectively), with neutropenia and leukopenia being more frequent in the G+C group. CONCLUSIONS: Although this trial did not show superiority for PFS of G+C versus TC, the 6-month PFS increased in G+C treated patients. Further refinement of this strategy should focus on identification of predictive markers for patient selection.

Synthetic vs. natural/biodegradable polymers for delivery of shRNA-based cancer therapies.

DNA vector-based short hairpin RNA (shRNA) as a means of effecting RNA interference (RNAi) is a promising mechanism for the precise disruption of gene expression to achieve a therapeutic effect. The clinical usage of shRNA therapeutics in cancer is limited by obstacles related to effective delivery into the nuclei of target cancer cells. Significant pre-clinical data have been amassed about biodegradable and non-biodegradable polymeric delivery vehicles that are relevant for shRNA delivery into humans. Here, we will review some leading candidates for clinical usage with a focus on studies relating to their potential for usage in cancer shRNA therapeutics and discuss some of the advantages and disadvantages of using biodegradable and non-biodegradable delivery vehicles.

Phase I clinical and pharmacodynamic evaluation of oral CI-1033 in patients with refractory cancer.

PURPOSE: To determine the tolerability and pharmacokinetics of CI-1033 given daily for 7 days of a 21-day cycle. Tumor response and changes in erbB receptor tyrosine kinase activity in tumor and skin tissue were examined, and modulation of potential biomarkers in plasma was explored. DESIGN: This was a dose-finding phase I study in patients with advanced solid malignancies. Patients were evaluated for safety, pharmacokinetics, and tumor response. Pharmacodynamic markers, such as Ki67, p27, and erbB receptor status, were assessed in tumor and skin tissue using immunohistochemical and immunoprecipitation methodologies. Plasma biomarkers HER2, vascular endothelial growth factor, interleukin-8, and matrix metalloproteinase-9 were evaluated using immunologic techniques. RESULTS: Fifty-three patients were enrolled in the study. Dose-limiting toxicity (emesis, persistent rash, and mouth ulcer) was observed at 750 mg. The maximum tolerated dose was 650 mg. There were no confirmed objective responses. CI-1033 treatment showed down-regulation of epidermal growth factor receptor, HER2, and Ki67 in a variety of tumor tissues and up regulation of p27 in skin tissue. Plasma HER2 was reduced following CI-1033 administration, but no consistent change in vascular endothelial growth factor, interleukin-8, or matrix metalloproteinase-9 was noted. CI-1033 plasma concentrations were proportional to dose. CONCLUSION: The safety and pharmacokinetic profile of CI-1033 was favorable for multidose oral administration. Evidence of modulation of erbB receptor activity in tumor and skin tissue was accompanied by changes in markers of proliferation and cell cycle inhibition. Additional clinical trials are warranted in defining the role of CI-1033 in the treatment of cancer and further assessing the utility of antitumor markers.

KRAS mutant allele-specific expression knockdown in pancreatic cancer model with systemically delivered bi-shRNA KRAS lipoplex.

The KRAS oncogene, present in over 90% of pancreatic ductal adenocarcinomas, is most frequently the result of one of three gain-of-function substitution mutations of codon 12 glycine. Thus far, RAS mutations have been clinically refractory to both direct and selective inhibition by systemic therapeutics. This report presents the results of pre-clinical assessment of a lipoplex comprising a plasmid-encoded, modular bi-functional shRNA (bi-shRNA), which executes selective and multi-mutant allelic KRASG12mut gene silencing, encased within a fusogenic liposome systemic delivery vehicle. Using both a dual luciferase reporter system and a Restriction Fragment Length Polymorphism (RFLP) assay, selective discrimination of KRASG12mut from KRASwt was confirmed in vitro in PANC1 cells. Subsequently, systemic administration of the bi-shRNAKRAS fusogenic lipoplex into female athymic Nu/Nu mice bearing PANC1 xenografts demonstrated intratumoral plasmid delivery, KRASG12mut knockdown, and inhibition of tumor growth, without adverse effect. Clinical trials with the bi-shRNA lipoplex have been implemented.

Phase 2 trial of Allovectin-7 in advanced metastatic melanoma.

Treatment of metastatic melanoma with chemotherapeutic regimens has led to disappointing response rates, duration of response and no appreciable impact on survival. Intralesional injection of a low dose of an HLA-B7/beta2 microglobulin plasmid formulated with cationic lipids (Allovectin-7 is a registered trademark of Vical, Incorporated, San Diego, California, USA) has been shown previously to be safe and well tolerated. A phase 2, open-label study was performed at 16 centers in the United States. Seventy-seven patients were treated with 10 mug intralesional Allovectin-7 weekly for 6 weeks and clinical response to treatment were evaluated by World Health Organization criteria. Minimal adverse events were associated with the Allovectin-7 injections. Seven patients (9.1%) had complete or partial response with 4.8 months median duration of response. Allovectin-7 was shown to be safe and exhibit biological activity at this dose. Its safety profile may enable Allovectin-7 to be used at higher doses, which may provide greater clinical activity.

Pegylated interferon alfa-2b treatment for patients with solid tumors: a phase I/II study.

PURPOSE: The efficacy of interferon alfa has been established in treating advanced melanoma and renal cell carcinoma (RCC) patients. We conducted a phase I/II study to determine the maximum-tolerated dose (MTD), the safety and tolerability, and the preliminary efficacy of once-weekly pegylated interferon alfa-2b (IFNalpha-2b) in patients with advanced solid tumors (primarily RCC). PATIENTS AND METHODS: To determine the MTD, 35 patients with a variety of advanced solid tumors received 0.75 to 7.5 micro g/kg/wk of pegylated IFNalpha-2b by subcutaneous injection for 12 weeks. An additional 35 previously untreated RCC patients received 6.0 and 7.5 micro g/kg/wk for up to 12 weeks. Patients with a response or stable disease after 12 weeks were eligible for the extension protocol and were treated for up to 1 year or until disease progression. RESULTS: The MTD for pegylated IFNalpha-2b at 12 weeks was 6.0 micro g/kg/wk. One year of 6.0 micro g/kg/wk was well tolerated with appropriate dose modification; no grade 3 or 4 fatigue occurred, and safety was comparable with that with nonpegylated IFNalpha-2b. The most common nonhematologic adverse events included mild to moderate nausea, anorexia, and fatigue. Six patients had grade 3 or 4 hematologic toxicity. Twenty-nine patients continued on the extension protocol. Four patients had a complete response, and five patients had a partial response. Among 44 previously untreated RCC patients, the objective response rate was 14%. Median survival for all RCC patients was 13.2 months. CONCLUSION: Pegylated IFNalpha-2b was active and well tolerated in patients with metastatic solid tumors, including RCC, at doses up to 6.0 micro g/kg/wk.

Liposomal insulin promoter-thymidine kinase gene therapy followed by ganciclovir effectively ablates human pancreatic cancer in mice.

PDX1 is overexpressed in pancreatic cancer, and activates the insulin promoter (IP). Adenoviral IP-thymidine kinase and ganciclovir (TK/GCV) suppresses human pancreatic ductal carcinoma (PDAC) in mice, but repeated doses carry significant toxicity. We hypothesized that multiple cycles of liposomal IP-TK/GCV ablate human PDAC in SCID mice with minimal toxicity compared to adenoviral IP-TK/GCV. SCID mice with intraperitoneal human pancreatic cancer PANC-1 tumor implants were given a single cycle of 35 µg iv L-IP-TK, or four cycles of 1, 10, 20, 30, or 35 µg iv L-IP-TK (n = 20 per group), followed by intraperitoneal GCV. Insulin and glucose levels were monitored in mice treated with four cycles of 35 µg iv L-IP-TK. We found that four cycles of 10-35 µg L-IP-TK/GCV ablated more PANC-1 tumor volume compared to a single cycle with 35 µg. Mice that received four cycles of 10 µg L-IP-TK demonstrated the longest survival (P < 0.05), with a median survival of 126 days. In comparison, mice that received a single cycle of 35 µg L-IP-TK/GCV or GCV alone survived a median of 92 days and 68.7 days, respectively. There were no significant changes in glucose or insulin levels following treatment. In conclusion, multiple cycles of liposomal IP-TK/GCV ablate human PDAC in SCID mice with minimal toxicity, suggesting non-viral vectors are superior to adenoviral vectors for IP-gene therapy.

Phase I study of intravenously administered ATI-1123, a liposomal docetaxel formulation in patients with advanced solid tumors.

PURPOSE: ATI-1123 is a liposomal formulation of docetaxel and may be administered without the premedications and hypersensitivity reactions. This Phase I study examines the safety, tolerability, pharmacokinetics (PKs), and antitumor activity of ATI-1123. METHODS: Patients with advanced solid malignancies received escalating doses of ATI-1123 intravenously over 1-h every 3 weeks. The dosing commenced using an accelerated titration design and was followed by a modified 3 + 3 Fibonacci schema to determine maximally tolerated dose (MTD). Plasma was analyzed for encapsulated/non-encapsulated docetaxel; PK analyses were performed using model independent method. Response was assessed using RECIST criteria. RESULTS: In total, 29 patients received doses ranging from 15 to 110 mg/m(2). At 110 mg/m(2), two of six patients experienced dose-limiting toxicities including grade 3 stomatitis and febrile neutropenia. The 90 mg/m(2) cohort was expanded to ten patients and identified as the MTD. The most common adverse events were fatigue, nausea, neutropenia, anemia, anorexia, and diarrhea. ATI-1123 exhibited linear and dose proportional PKs. One patient with lung cancer had confirmed partial response, and stable disease was observed in 75 % patients. CONCLUSIONS: ATI-1123 demonstrated an acceptable tolerability and favorable PK profile in patients with solid tumors. Our results provide support for Phase II trials to determine the antitumor activity of this drug.

Hereditary inclusion body myopathy: single patient response to intravenous dosing of GNE gene lipoplex.

Hereditary inclusion body myopathy (HIBM) is an autosomal recessive adult-onset myopathy due to mutations in the GNE (UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase) gene. Affected patients have no therapeutic options. We have previously demonstrated in preclinical testing the ability to safely correct GNE gene function through liposomal delivery of the wild-type GNE gene. Results were verified in a single patient treated by intravenous infusion of GNE gene lipoplex. A single patient (patient 001) with severe HIBM treated with a compassionate investigational new drug received seven doses of GNE gene lipoplex via intravenous infusion at the following doses: 0.4, 0.4, 1.0, 4.0, 5.0, 6.0, and 7.0 mg of DNA. GNE transgene expression, downstream induction of sialic acid, safety, and muscle function were evaluated. Transient low-grade fever, myalgia, tachycardia, transaminase elevation, hyponatremia, and hypotension were observed after infusion of each dose of GNE gene lipoplex. Quadriceps muscle expression of the delivered GNE, plasmid, and RNA was observed 24 hr after the 5.0-mg dose and at significantly greater levels 72 hr after the 7.0-mg infusion in comparison with expression in quadriceps muscle immediately before infusion. Sialic acid-related proteins were increased and stabilization in the decline of muscle strength was observed. We conclude that clinical safety and activity have been demonstrated with intravenous infusion of GNE gene lipoplex. Further assessment will involve a phase I trial of intravenous administration of GNE gene lipoplex in individuals with less advanced HIBM with more muscle function.

Nonviral delivery vehicles for use in short hairpin RNA-based cancer therapies.

The use of DNA vector-based short hairpin (sh)RNA for RNA interference shows promise as a precise means for the disruption of gene expression to achieve a therapeutic effect. The in vivo usage of shRNA therapeutics in cancer is limited by obstacles related to effective delivery into the nuclei of target cancer cells. Nonviral delivery vehicles that are relevant for shRNA delivery into humans belong to a group of substances about which significant preclinical data has been amassed to show an acceptable safety profile, resistance to immune defenses and good transfection efficiency. Here, we review the most promising current nonviral gene delivery vehicles with a focus on their potential use in cancer shRNA therapeutics.