Marcia Pomplun

Phase I clinical trial of intravenous L-buthionine sulfoximine and melphalan: An attempt at modulation of glutathione

PURPOSE A phase I dose-escalation trial of intravenous (IV) L-buthionine-SR-sulfoximine (BSO) with melphalan (L-PAM) was performed to determine the toxicity and biologic activity of BSO, administered as a short infusion every 12 hours, and the combination of BSO plus L-PAM. PATIENTS AND METHODS Twenty-eight patients with refractory malignancies received 30-minute infusions of BSO every 12 hours for 6 to 10 doses in week 1 followed in week 2 by either IV L-PAM (15 mg/m2) alone or BSO as in week 1 with L-PAM. Patients received the combination in week 5 (course no. 2) if they received L-PAM alone during week 2 and vice versa. BSO doses ranged from 1.5 g/m2 to 13.104 g/m2. RESULTS The only toxicity observed with BSO infusions was occasional nausea/vomiting. Evaluation of 23 paired courses (L-PAM plus BSO v L-PAM) showed significantly (P < .001) greater leukopenia and thrombocytopenia with L-PAM plus BSO. No other significant toxicity was noted. Measurement of intracellular glutathione (GSH) levels in peripheral mononuclear cells (PBLs) of all patients receiving BSO showed a consistent, non-dose-dependent, linear decrease in GSH with repeated BSO doses. Maximal GSH depletion (40% of baseline values, absolute values 200 to 250 ng/10(6) PBLs) was noted after the sixth BSO dose; extended BSO dosing schedules beyond six total BSO doses did not further deplete GSH. Evaluation of gamma-glutamylcysteine synthetase (GCS) activity showed marked inhibition near the end of each infusion with near complete recovery of GCS activity before the next BSO dose. The pattern of GCS inhibition mirrored the plasma BSO concentrations with peak values (level 6, 4 to 8 mmol/L L,R+L,S BSO) observed at the end of the infusion with a rapid decrease in plasma concentrations with an estimated half-life (t1/2) of less than 2 hours. Differential elimination of the R+S stereoisomers was observed. Analysis of L-PAM pharmacokinetics showed marked interpatient variability and a significant decrease in total-body clearance (P = .01) and volume of distribution (P = .03) in courses with L-PAM plus BSO as compared with L-PAM alone. CONCLUSION This study shows that BSO alone and in combination with L-PAM can be safely given to patients, but that a schedule of short infusions every 12 hours does not result in GSH depletion less than 30% of baseline values.

A randomized, double-blind, placebo-controlled phase 3 skin cancer prevention study of {alpha}-difluoromethylornithine in subjects with previous history of skin cancer.

Preclinical studies have shown that the inhibition of ornithine decarboxylase (ODC) by α-difluoromethylornithine (DFMO) and resultant decreases in tissue concentrations of polyamines (putrescine and spermidine) prevents neoplastic developments in many tissue types. Clinical studies of oral DFMO at 500 mg/m2/day revealed it to be safe and tolerable and resulted in significant inhibition of phorbol ester–induced skin ODC activity. Two hundred and ninety-one participants (mean age, 61 years; 60% male) with a history of prior nonmelanoma skin cancer (NMSC; mean, 4.5 skin cancers) were randomized to oral DFMO (500 mg/m2/day) or placebo for 4 to 5 years. There was a trend toward a history of more prior skin cancers in subjects randomized to placebo, but all other characteristics including sunscreen and nonsteroidal anti-inflammatory drug use were evenly distributed. Evaluation of 1,200 person-years of follow-up revealed a new NMSC rate of 0.5 events/person/year. The primary end point, new NMSCs, was not significantly different between subjects taking DFMO and placebo (260 versus 363 cancers, P = 0.069, two-sample t test). Evaluation of basal cell (BCC) and squamous cell cancers separately revealed very little difference in squamous cell cancer between treatment groups but a significant difference in new BCC (DFMO, 163 cancers; placebo, 243 cancers; expressed as event rate of 0.28 BCC/person/year versus 0.40 BCC/person/year, P = 0.03). Compliance with DFMO was >90% and it seemed to be well tolerated with evidence of mild ototoxicity as measured by serial audiometric examination when compared with placebo subjects. The analysis of normal skin biopsies revealed a significant (P < 0.05) decrease in 12-0-tetradecanoylphorbol-13-acetate–induced ODC activity (month 24, 36, and 48) and putrescine concentration (month 24 and 36 only) in DFMO subjects. Subjects with a history of skin cancer taking daily DFMO had an insignificant reduction (P = 0.069) in new NMSC that was predominantly due to a marked reduction in new BCC. Based on these data, the potential of DFMO, alone or in combination, to prevent skin cancers should be explored further. Cancer Prev Res; 3(1); 35–47

A randomized, double-blind, placebo-controlled phase 3 skin cancer prevention study of DFMO in subjects with previous history of skin cancer

Preclinical studies have shown that the inhibition of ornithine decarboxylase (ODC) by α-difluoromethylornithine (DFMO) and resultant decreases in tissue concentrations of polyamines (putrescine and spermidine) prevents neoplastic developments in many tissue types. Clinical studies of oral DFMO at 500 mg/m2/day revealed it to be safe and tolerable and resulted in significant inhibition of phorbol ester–induced skin ODC activity. Two hundred and ninety-one participants (mean age, 61 years; 60% male) with a history of prior nonmelanoma skin cancer (NMSC; mean, 4.5 skin cancers) were randomized to oral DFMO (500 mg/m2/day) or placebo for 4 to 5 years. There was a trend toward a history of more prior skin cancers in subjects randomized to placebo, but all other characteristics including sunscreen and nonsteroidal anti-inflammatory drug use were evenly distributed. Evaluation of 1,200 person-years of follow-up revealed a new NMSC rate of 0.5 events/person/year. The primary end point, new NMSCs, was not significantly different between subjects taking DFMO and placebo (260 versus 363 cancers, P = 0.069, two-sample t test). Evaluation of basal cell (BCC) and squamous cell cancers separately revealed very little difference in squamous cell cancer between treatment groups but a significant difference in new BCC (DFMO, 163 cancers; placebo, 243 cancers; expressed as event rate of 0.28 BCC/person/year versus 0.40 BCC/person/year, P = 0.03). Compliance with DFMO was >90% and it seemed to be well tolerated with evidence of mild ototoxicity as measured by serial audiometric examination when compared with placebo subjects. The analysis of normal skin biopsies revealed a significant (P < 0.05) decrease in 12-0-tetradecanoylphorbol-13-acetate–induced ODC activity (month 24, 36, and 48) and putrescine concentration (month 24 and 36 only) in DFMO subjects. Subjects with a history of skin cancer taking daily DFMO had an insignificant reduction (P = 0.069) in new NMSC that was predominantly due to a marked reduction in new BCC. Based on these data, the potential of DFMO, alone or in combination, to prevent skin cancers should be explored further. Cancer Prev Res; 3(1); 35–47

A pilot, first-in-human, pharmacokinetic study of 9cUAB30 in healthy volunteers.

9cUAB30 is a synthetic analog of 9-cis -retinoic acid with chemopreventive activity in cell lines and in animal models. The purpose of this first-in-human evaluation of 9cUAB30 was to evaluate the single-dose pharmacokinetic profile and toxicity of the compound in healthy volunteers at 3 dose levels. This study enrolled 14 patients to receive a single dose of 5, 10, or 20 mg of 9cUAB30. Plasma and urine samples were collected to assess 9cUAB30 concentrations by a validated LC/MS MS method. 9cUAB30 was well tolerated, with 1 patient experiencing grade 2 toxicity and no grade 3 or 4 toxicities reported. T max occurred approximately 3 hours after dose administration with the plasma half-life ranging from 2.79 to 7.21 hours. AUC increased linearly across the examined dose range of 5 to 20 mg; C max was proportional to the log of the dose. The plasma clearance ranged from 25 to 39 L/h compared to the renal clearance which ranged from 0.018 to 0.103 L/h. 9cUAB30 has a favorable toxicity and pharmacokinetic profile, with oral availability and primarily hepatic metabolism. Further dose ranging studies with once a day dosing are underway.Cancer Prev Res; 3(12); 1565–70. ©2010 AACR.

Stability of unused reconstituted bortezomib in original manufacturer vials

Background. Bortezomib is a modified dipeptidyl boronic acid analogue used to treat multiple myeloma, mantle cell lymphoma, and, more recently, renal transplantation graft rejection. As per manufacturer recommendations, bortezomib is to be administered within 8 h of preparation or may be stored for up to 8 h in the vial or a syringe following reconstitution. Preserving unused reconstituted bortezomib beyond these 8 h may allow for cost savings. This study aims to examine the stability of unused reconstituted bortezomib when stored at 4°C for up to 15 days. Methods. Using an LC-MS/MS assay, the concentration of reconstituted bortezomib was measured at predetermined time points following storage at 4°C in the manufacturer vial. Percent bortezomib remaining at a time point was calculated versus initial bortezomib concentration. Results. The concentrations of bortezomib were found to be 51.93 ng/mL ± 4.60 after 1 day of storage, 57.40 ng/mL ± 4.77 after 8 days of storage, and 49.43 ng/mL ± 2.85 after 15 days of storage. The percent of bortezomib remaining was 110.53% and 95.19% after 8 days and 15 days, respectively. Conclusion. Unused reconstituted bortezomib is stable for up to 15 days stored at 4°C in the original manufacturer vial. Such use of bortezomib may improve cost efficiency by reducing bortezomib waste.

Phase I Trial of the Polyamine Analog N1,N14-Diethylhomospermine (DEHSPM) in Patients with Advanced Solid Tumors

Background: This phase I study was conducted to determine maximal tolerated dose (MTD) and dose-limiting toxicities (DLT) in patients with advanced solid tumors treated with the polyamine analog N1,N14-diethylhomospermine (DEHSPM). Methods: Patients were treated with DEHSPM administered as a subcutaneous (SC) injection daily for five consecutive days repeated every 4 weeks. Three dose levels were examined starting at 12.5 mg/m2/day, escalating to 37.5 mg/m2/day. Results: A total of 15 patients were enrolled. Dose limiting toxicities (grade 3 or 4) included nausea, vomiting, constipation, ileus, elevations of aspartate aminotransferase (AST) and alkaline phosphatase, hyperbilirubinemia, and ventricular bigeminy. Conclusion: DEHSPM given as a SC injection is overall well tolerated at lower doses, but significant toxicities were observed at the 37.5mg/m2/day dose level. MTD was established at 25 mg/m2/day but further investigation with this study drug is not recommended secondary to the potential for neurotoxicities and hepatic damage as a result of cumulative doses.

Stability of a heparin-free 50% ethanol lock solution for central venous catheters.

Objectives. To determine the stability of a compounded 50% ethanol solution (v/v) in syringes used for ethanol locks for central venous catheters. Design. Syringes were compounded with 50% ethanol solution (v/v) and were tested for ethanol concentration over a 28 day period. Syringes were stored at room temperature not protected from light and assayed on days 0, 1, 2, 3, 6, 7, 10, 15, 17, 21, and 28. Ethanolic content was determined using gas chromatography/flame ionization detection (GC/ FID) Varian CP-WAX58 (FFAP) CB capillary column. Setting. University of Wisconsin Comprehensive Cancer Center. Results. The mean value for all samples over 28 days was found to be 47.08% with a standard deviation of 2.72. Mean ethanol concentrations ranged from 43 to 52% over the 28 day period and did not vary with time. Conclusions. Ethanol is an effective disinfectant against a broad range of micro-organisms, including bacteria and fungi. Retrospective trials have suggested that the efficacy of an ethanol lock solution is superior to systemic antibiotics to treat and/or prevent central line venous infections; however, there is not a commercially available pharmaceutical product and ethanol 50% solutions are currently compounded. These findings suggest that a 50% (v/v) ethanol solution stored in a syringe at room temperature, not protected from light is stable over a 28 day period. J Oncol Pharm Practice (2007) 13: 33–37.

Establishment and characterization of irinotecan-resistant human non-small cell lung cancer A549 cells

Irinotecan (CTP-11) is a topoisomerase I inhibitor used in the treatment of colorectal cancer and non-small cell lung cancer (NSCLC). Despite an initial response to therapy, resistance to irinotecan reduces its efficacy. We isolated irinotecan-resistant human NSCLC A549 cells, termed A549/CTP-11R cells. A549/CTP-11R cells were resistant to irinotecan, as well as paclitaxel, gemcitabine and carboplatin. Curcumin, a nuclear factor-κB (NF-κB) inhibitor, increased the sensitivity to irinotecan of A549/CTP-11R cells. The expression level of Bcl-XL and X-linked inhibitor of apoptosis protein, target genes of NF-κB, in A549/CTP-11R cells was higher than that in A549 cells. Our result suggests that the addition of curcumin to irinotecan reverses irinotecan resistance in NSCLC.

Soy food frequency questionnaire does not correlate with baseline isoflavone levels in patients with bladder cancer

Background The isoflavone genistein, a natural soy product with receptor tyrosine kinase-inhibiting activity, as well as phytoestrogenic and other potential anticarcinogenic effects, is being studied as an anticancer agent. Since isoflavones are commonly consumed in food products containing soy proteins, a method to control for baseline isoflavone consumption is needed. Methods HPLC was used to evaluate baseline plasma and urine concentrations of isoflavone in fifty-four participants with bladder cancer enrolled on a phase II chemoprevention study of G-2535. The soy food frequency questionnaire was used to assess participant’s baseline soy intake. The association between baseline isoflavone concentrations and intakes for genistein and daidzein was assessed by the Spearman’s rank correlation coefficient. Results The majority of participants had no detectable genistein or daidzein in plasma at baseline. The median and range of values were 0 (0–1480) nmol/L for genistein, and 0 (0–1260) nmol/L for daidzein. In urine, the median and range of values were 91.0 (0–9030) nmol/L for genistein and 623 (0–100,000) nmol/L for daidzein. The median and range of weekly estimated genistein intake was 0 (0–236) mg/wk; the median and range of weekly estimated daidzein intake was 0 (0–114) mg/wk. There was no relationship to soy intake as measured by the food frequency questionnaire and baseline isoflavone levels in plasma or urine and the Spearman’s rank correlation coefficients were not significant. Conclusion The soy food frequency questionnaire did not correlate with plasma or urine concentrations of either isoflavone. Impact Alternative methods for controlling for soy consumption, including measuring plasma and urine concentrations, in isoflavone chemoprevention trials should be considered.