Mitochondrial Superoxide Dismutase in Cisplatin-Induced Kidney Injury.

Cisplatin is a chemotherapy agent commonly used to treat a wide variety of cancers. Despite the potential for both severe acute and chronic side effects, it remains a preferred therapeutic option for many malignancies due to its potent anti-tumor activity. Common cisplatin-associated side-effects include acute kidney injury (AKI) and chronic kidney disease (CKD). These renal injuries may cause delays and potentially cessation of cisplatin therapy and have long-term effects on renal function reserve. Thus, developing mechanism-based interventional strategies that minimize cisplatin-associated kidney injury without reducing efficacy would be of great benefit. In addition to its action of cross-linking DNA, cisplatin has been shown to affect mitochondrial metabolism, resulting in mitochondrially derived reactive oxygen species (ROS). Increased ROS formation in renal proximal convoluted tubule cells is associated with cisplatin-induced AKI and CKD. We review the mechanisms by which cisplatin may induce AKI and CKD and discuss the potential of mitochondrial superoxide dismutase mimetics to prevent platinum-associated nephrotoxicity.

Phase 1b/2a Trial of the Superoxide Dismutase Mimetic GC4419 to Reduce Chemoradiotherapy-Induced Oral Mucositis in Patients With Oral Cavity or Oropharyngeal Carcinoma.

PURPOSE: To assess the safety of the superoxide dismutase mimetic GC4419 in combination with radiation and concurrent cisplatin for patients with oral cavity or oropharyngeal cancer (OCC) and to assess the potential of GC4419 to reduce severe oral mucositis (OM). PATIENTS AND METHODS: Patients with locally advanced OCC treated with definitive or postoperative intensity modulated radiation therapy (IMRT) plus cisplatin received GC4419 by 60-minute intravenous infusion, ending <60 minutes before IMRT, Monday through Friday for 3 to 7 weeks, in a dose and duration escalation study. Oral mucositis was assessed twice weekly during and weekly after IMRT. RESULTS: A total of 46 patients received GC4419 in 11 separate dosing and duration cohorts: dose escalation occurred in 5 cohorts receiving 15 to 112 mg/d over 3 weeks (n=20), duration escalation in 3 cohorts receiving 112 mg/d over 4 to 6 weeks (n=12), and then 3 additional cohorts receiving 30 or 90 mg/d over 6 to 7 weeks (n=14). A maximum tolerated dose was not reached. One dose-limiting toxicity (grade 3 gastroenteritis and vomiting with hyponatremia) occurred in each of 2 separate cohorts at 112 mg. Nausea/vomiting and facial paresthesia during infusion seemed to be GC4419 dose-related. Severe OM occurred through 60 Gy in 4 of 14 patients (29%) dosed for 6 to 7 weeks, with median duration of only 2.5 days. CONCLUSIONS: The safety of GC4419 concurrently with chemoradiation for OCC was acceptable. Toxicities included nausea/vomiting and paresthesia. Doses of 30 and 90 mg/d administered for 7 weeks were selected for further study. In an exploratory analysis, severe OM seemed less frequent and briefer than expected.

Double-blind, placebo-controlled, randomized phase 2 study of the proapoptotic agent AT-101 plus docetaxel, in second-line non-small cell lung cancer.

BACKGROUND: AT-101 is an inhibitor of Bcl-2 family proteins including Bcl-2, Bcl-xL, Mcl-1, and Bcl-w. In vivo and in vitro studies have exhibited broad activity of AT-101, including synergy with docetaxel in non-small cell lung cancer tumor models. METHODS: We conducted a prospective, randomized (1:1), double-blind, placebo-controlled phase 2 study. Eligible patients must have received one prior chemotherapeutic regimen for advanced or metastatic non-small cell lung cancer and may also have received therapy with an epidermal growth factor receptor inhibitor. Patients received AT-101 (40 mg b.i.d. × 3 days) or placebo in combination with docetaxel (75 mg/m on day 1) every 21 days. The primary endpoint was progression-free survival (PFS) as determined by independent review; other endpoints include overall survival and PFS by investigator determination. Approximately 102 patients were planned to provide 70 events (80% power, hazard ratio [HR] of 0.6, one-sided alpha of 0.1). RESULTS: : One hundred six patients were assigned to treatment and 105 patients received at least one dose of AT-101 or placebo. Baseline factors were balanced between treatment groups: median age 59 years; 77% men, and 79% current or former smokers. Ninety-three percent of patients had distant metastatic disease at randomization and 56% squamous histology. The most frequently reported adverse events were fatigue (18%), anemia (18%), and dyspnea (18%). No statistically significant differences in serious adverse events were observed between AT-101 and placebo; grade 1/2 headaches appeared more frequently with AT-101 (9% versus 0%) and neutropenia was reported more frequently in the docetaxel plus placebo arm compared with docetaxel plus AT-101 (17% versus 8%). Unlike trials with continuous daily dosing of AT-101, no cases of small bowel obstruction were reported. The response rate and median PFS were not different between the arms by independent review, PFS 7.5 weeks for docetaxel plus AT-101 and 7.1 weeks for docetaxel plus placebo arms (HR, 1.04; p = 0.57). The median overall survival was 7.8 months for docetaxel plus AT-101 versus 5.9 months for docetaxel plus placebo (HR, 0.82; p = 0.21). CONCLUSIONS: The primary endpoint of improved PFS for AT-101 plus docetaxel was not met. AT-101 plus docetaxel was well tolerated with an adverse event profile indistinguishable from the base docetaxel regimen. AT-101 is the first oral, pan Bcl-2 family inhibitor to exhibit a possible survival benefit in a randomized study.

A phase I trial of aprinocarsen (ISIS 3521/LY900003), an antisense inhibitor of protein kinase C-alpha administered as a 24-hour weekly infusion schedule in patients with advanced cancer.

PURPOSE: A phase I study was performed to determine the maximum tolerated dose (MTD), safety profile and pharmacology of aprinocarsen (ISIS 3521), an antisense oligonucleotide to protein kinase C-alpha, in patients with refractory solid tumors. EXPERIMENTAL DESIGN: Fourteen patients were treated in sequential cohorts of aprinocarsen by 24-hour continuous infusion (CIV), weekly, at doses of 6, 12, 18 and 24 mg/kg. RESULTS: One grade 4 toxicity was observed, transient grade 4 neutropenia at 18 mg/kg. Grade 3 toxicities included neutropenia at 12 mg/kg, fever and hemorrhage at 18 mg/kg, and neutropenia, nausea, and chills at 24 mg/kg. Grade 2 toxicities included thrombocytopenia myalgias, chills, headache, fatigue, fever and nausea/vomiting. Mean prothrombin times and activated partial thromboplastin times (aPTT) increased by 10% and 29% from baseline (p = 0.006 and 0.005). Mean complement split products (Bb and C3a) increased 1.6-fold and 3.6-fold (from p = 0.014 and 0.004, respectively). These changes correlated with dose and were transient with recovery to baseline by day 7. Steady state plasma concentrations (Css) of aprinocarsen were achieved within four hours. Css better described changes in aPTT than dose. Clinical evidence of complement activation was not observed. CONCLUSIONS: In contrast to 21-day protracted infusion schedules, delivery of aprinocarsen over a 24-hour infusion schedule showed concentration-dependent effects on coagulation and complement, which are consistent with nonclinical toxicology studies performed in the phosphorothioate DNA antisense drug class. These coagulation and complement changes resulted in a maximum tolerated dose 24 mg/kg.

Efficacy and toxicity of the antisense oligonucleotide aprinocarsen directed against protein kinase C-alpha delivered as a 21-day continuous intravenous infusion in patients with recurrent high-grade astrocytomas.

Protein kinase C alpha (PKC-alpha) is a cytoplasmic serine threonine kinase involved in regulating cell differentiation and proliferation. Aprinocarsen is an antisense oligonucleotide against PKC-alpha that reduces PKC-alphain human cell lines and inhibits a human glioblastoma tumor cell line in athymic mice. In this phase 2 study, aprinocarsen was administered to patients with recurrent high-grade gliomas by continuous intravenous infusion (2.0 mg/kg/day for 21 days per month). Twenty-one patients entered this trial. Their median age was 46 years (range, 28-68 years), median Karnofsky performance status was 80 (range, 60-100), median tumor volume was 58 cm3 (range, 16-254 cm3), and histology included glioblastoma multiforme (n = 16), anaplastic oligodendroglioma (n = 4), and anaplastic astrocytoma (n = 1). The number of prior chemotherapy regimens included none (n = 3), one (n = 10), and two (n = 8). No tumor responses were observed. Patients on this therapy rapidly developed symptoms of increased intracranial pressure with increased edema, enhancement, and mass effect on neuroimaging. The median time to progression was 36 days, and median survival was 3.4 months. The observed toxicities were mild, reversible, and uncommon (grade 3 thrombocytopenia [n = 3] and grade 4 AST [n = 1]), and no coagulopathy or CNS bleeding resulted from this therapy. Plasma concentrations of aprinocarsen during the infusion exhibited significant interpatient variability (mean = 1.06 mug/ml; range, 0.34-6.08 mug/ml). This is the first study to use an antisense oligonucleotide or a specific PKC-alpha inhibitor in patients with high-grade gliomas. No clinical benefit was seen. The rapid deterioration seen in these patients could result from tumor growth or an effect of aprinocarsen on bloodbrain barrier integrity.

A Phase II trial of aprinocarsen, an antisense oligonucleotide inhibitor of protein kinase C alpha, administered as a 21-day infusion to patients with advanced ovarian carcinoma.

BACKGROUND: It has been postulated that protein kinase C alpha (PKC-alpha) plays a pivotal role in signal transduction in tumor cancer cells. Aprinocarsen, a 20-base antisense oligonucleotide, has shown ability to inhibit PKC-alpha protein expression and inhibit tumor growth in human xenograft models. In a previous Phase I trial, the authors demonstrated the safety and some evidence of activity in ovarian carcinoma of aprinocarsen administered as a 21-day, continuous, intravenous infusion. METHODS: In this Phase II trial, 36 patients with advanced ovarian carcinoma were treated with aprinocarsen at a dose of 2 mg/kg per day delivered as a 21-day, continuous, intravenous infusion. The primary objective was to determine the antitumor response, and the secondary objectives were to evaluate toxicity and to evaluate effects on quality of life (QOL). RESULTS: Between September 1997 and December 1999, 36 patients (median age, 58 years) were enrolled in this trial. Patients were stratified into 2 groups: a platinum-sensitive group (n = 12 patients) and a platinum-resistant group (n = 24 patients). All 36 patients were evaluable for toxicity, and 27 patients were fully assessable for antitumor response after 2 cycles of therapy. All patients had received prior treatments. No objective responses were noted in the platinum-sensitive group. In the platinum-resistant group, 1 patient had some evidence of antitumor activity indicated by a decrease in serum CA 125 and stable disease on imaging studies for 8 months. No changes were noted in overall patient ratings for any of the five QOL domains. CONCLUSIONS: When it was administered as a single agent, aprinocarsen did not have significant clinical activity in patients with advanced ovarian carcinoma. Further study may be warranted in combination with platinum-based regimens.

Applying antisense technology: Affinitak and other antisense oligonucleotides in clinical development.

Progress in the development of antisense drugs over the last decade has led to the approval of the first such drug--Vitravene for AIDS-related CMV retinitis--and the development of a large number of antisense drugs in clinical trials. Antisense drugs are now being studied in Phase 3 trials for patients with cancer and inflammatory bowel disease. Other antisense drugs are in development for rheumatoid arthritis, other inflammatory conditions, and hepatitis C. Still other antisense drugs are entering clinical trials for treatment of metabolic conditions such as diabetes and hyperlipidemia. These latter applications provide the potential for target effects to be more directly measured in the clinic. Improved antisense chemistry, which will enhance the feasibility of subcutaneous and oral administration of antisense drugs and offer the potential of less frequent dosing, is expected to further expand the opportunities for antisense drug development.

Phase I clinical and pharmacokinetic study of protein kinase C-alpha antisense oligonucleotide ISIS 3521 administered in combination with 5-fluorouracil and leucovorin in patients with advanced cancer.

The present study was designed to determine the maximum tolerated dose (MTD), toxicity profile, pharmacokinetics (PKs), and antitumor activity of the protein kinase C-alpha antisense oligonucleotide ISIS 3521 (ISIS Pharmaceuticals, Inc., Carlsbad, CA) when administered in combination with 5-fluorouracil (5-FU) and leucovorin (LV). Patients with refractory solid tumors received ISIS 3521 as a 21-day continuous infusion administered simultaneously with 5-FU and LV given daily for 5 days repeated every 4-5 weeks (one cycle). 5-FU and ISIS 3521 PK analysis were performed on samples taken during the first cycle in all patients. Fifteen patients received ISIS 3521 at one of three dose levels: (a) 1.0 (n = 3 patients); (b) 1.5 (n = 3 patients); and (c) 2.0 (n = 9 patients) mg/kg/day. All patients simultaneously received 5-FU (425 mg/m(2)/day) and LV (20 mg/m(2)/day) for 5 consecutive days. Grade 1-2 toxicities included alopecia, fatigue, mucositis, diarrhea, anorexia, nausea/vomiting, and tumor pain. One patient had grade 3 chest pain considered to be related to 5-FU therapy, another patient had dose-limiting grade 3 mucositis resolving in <7 days, and one patient with a history of gastritis had an acute upper gastrointestinal bleed thought to be 5-FU-induced toxicity. Five patients developed cycle 1 grade 4 neutropenia, which resolved without colony-stimulating factors before the next treatment cycle. There were no effects on prothrombin time and activated partial thromboplastin time. A clinically defined MTD was not reached. The character and severity of these toxicities do not seem to be dose related, and, as such, there was no classical dose-limiting toxicity defining the MTD. ISIS 3521 PKs in the presence of 5-FU was consistent with those reported previously. 5-FU PK parameters were also similar in the presence or absence of ISIS 3521. Six of 14 patients ( approximately 43%) across all dose cohorts had an improvement in measurable tumor response ranging from minor reduction in tumor size (4 patients) to objective partial response (>50% reduction in tumor size, 2 patients). ISIS 3521 is tolerable at its recommended single-agent dose when given with 5-FU and LV. There is no apparent PK interaction between ISIS 3521 and 5-FU and LV. Antitumor activity was observed with the combination; however, it is uncertain whether clinical activity is a result of enhanced drug interaction. Our study warrants further exploration of efficacy in a Phase II and/or Phase III clinical trial setting.