Cancer Chemotherapy and Pharmacology

The aim of this study was to evaluate the efficacy of irinotecan (CPT-11) monotherapy and CPT-11 plus 5-fluorouracil (5-FU)/leucovorin (LV) combination (mFOLFIRI) as second-line treatment in patients with advanced gastric cancer (AGC). A total of 59 patients were randomly assigned to either CPT-11 (150 mg/m2 iv on day 1) or mFOLFIRI (CPT-11 150 mg/m2 plus LV 20 mg/m2 on day 1 followed by 5-FU 2,000 mg/m2 over 48 h), every 2 weeks. The primary end point was objective response rate (ORR). Following random assignment, 29 patients received CPT-11 and 30 patients mFOLFIRI. The ORR was 17.2 % [95 % confidence interval (CI) 3.4–30.9] and 20.0 % (95 % CI 5.6–34.3) for the CPT-11 and mFOLFIRI arms, respectively (P = 0.525). There was no significant difference in median progression-free survival: 2.2 months (95 % CI 0.2–4.3) for CPT-11 versus 3.0 months (95 % CI 2.0–3.7) for mFOLFIRI (P = 0.481) or in median overall survival: 5.8 months (95 % CI 3.0–8.7), compared with 6.7 months (95 % CI 5.3–8.2) (P = 0.514). Grade 3/4 toxicity was observed in 21 and 28 events in the CPT-11 and mFOLFIRI arms, respectively. Although this study had a small sample size and limited statistical power, CPT-11 monotherapy and mFOLFIRI appear to be equally active and tolerable as second-line chemotherapy for AGC. The addition of 5-FU/LV to CPT-11 did not significantly improve efficacy.

We conducted a phase I study to determine the recommended dose of selenomethionine (SLM) in combination with irinotecan that consistently results in a protective plasma selenium (Se) concentrations > 15 μM after 1 week of SLM loading. A 3-3 standard escalation design was followed. SLM was given orally twice daily (BID) for one week (loading) followed by continuous once daily (QD) dosing (maintenance). Seven dose levels of selenomethionine were investigated. Irinotecan was given intravenously at a fixed standard weekly dose, starting on the first day of maintenance SLM. Thirty-one patients were treated on study. Dose limiting diarrhea complicated by sepsis was noted in one of six patients at each of the dose-levels 1 and 7. Dose-levels ≥ 5 (4,800 mcg/dose loading maintenance) resulted in day 8 Se concentrations >15 μM while dose-level 7 (7,200 mcg/dose loading and maintenance) resulted in day 8 Se concentrations > 20 μM. No significant variations in SN-38 or biliary index were noted between weeks 1 and 4 of treatment. Despite achieving target Se concentrations, gastrointestinal and bone marrow toxicities were common and irinotecan dose modification was prevalent. Objective responses were seen in two patients and nine patients had disease control for 6 months or longer. Selenomethionine can be escalated safely to 7,200 mcg BID × 1 week followed by 7,200 mcg QD in combination with a standard dose of irinotecan. No major protection against irinotecan toxicity was established; however, interesting clinical benefits were noted-supporting the investigation of this combination in future efficacy trials.

Glioma, especially glioblastoma (GBM), is the most aggressive malignant brain tumor and its standard therapy is often ineffective because of temozolomide (TMZ) resistance. Reversal of the TMZ resistance might improve the prognosis of glioma patients. We previously found that interferon-α (IFN-α) and anti-epileptic drug levetiracetam (LEV) could sensitize glioma to TMZ, respectively. In this study, we further investigated the efficiency of combining of LEV and IFN-α for improving the efficacy of TMZ. We evaluated whether LEV and IFN-α could increase TMZ efficacy using colony formation assay and cell viability assay with MGMT-positive and MGMT-negative glioma cell lines in vitro. Subcutaneous xenografts and orthotopic xenografts mice models were used in vivo to observe the tumor growth and mice survival upon treatments with TMZ, TMZ + IFN-α, TMZ + LEV, or TMZ + LEV + IFN-α. The expression levels of MGMT, markers of pro-apoptotic and anti-apoptotic in tumor samples were analyzed by Western blotting. The combinational use of IFN-α, LEV, and TMZ showed the best anti-tumor activity in MGMT-positive cell lines (U138, GSC-1, U118, and T98 G). TMZ + LEV + IFN-α further obviously increased TMZ + LEV or TMZ + IFN-α efficiency in MGMT-positive cell lines, while not in negative cell lines (SKMG-4, U87, U373, and U251) in vitro, which were also observed in subcutaneous mice models (U138, GSC-1 compared to SKMG-4, U87) and orthotopic models (GSC-1) in vivo. Strikingly, the combination of LEV and IFN-α together with TMZ significantly prolonged the survival of mice with orthotopic GSC-1 glioma. Furthermore, we confirmed that the combination of LEV and IFN-α enhanced the inhibition of MGMT and the activation of apoptosis in U138 tumor on the basis of TMZ treatment. The combination use of LEV and IFN-α could be an optimal method to overcome TMZ resistance through obvious MGMT inhibition in MGMT-positive glioma.

Three cases of possible acute cardiopulmonary toxicity following the administration of vinorelbine are reported. The symptoms mimicked acute cardiac ischemia. However, neither ECG changes nor elevations of serum enzymes were observed. The outcome is favorable in 90% of patients developing this adverse event. The putative mechanism remains to be elucidated.

To investigate the associations of ANLN expression with prognosis of breast cancer and clinical outcome of anthracycline-based chemotherapy. This study enrolled 308 breast cancer patients in which 264 of them received anthracycline-based chemotherapy. Immunohistochemistry was used to detect ANLN expression level of the patients. Clinical characteristics of the patients were collected, and associations of ANLN expression with prognosis were analyzed. Our results showed that ANLN expression was associated with survival of breast cancer patients, and it was also related to clinical outcome of patients received anthracycline-based chemotherapy. Breast cancer patients with high expression of ANLN would have poor prognosis and poor clinical outcome to anthracycline-based chemotherapy. ANLN could be an independent prognosis predictor for breast cancer, and its expression might be used to predict the anthracycline-based chemotherapy clinical outcome in breast cancer patients.

To test the anticancer properties of a nonhydrolyzable ether-linked acetic acid analogue of vitamin E, 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxyacetic acid (α-TEA), and a derivative of camptothecin, 9-nitrocamptothecin (9-NC) singly and in combination against mouse mammary tumor cells (line 66 clone 4 stably transfected with green fluorescent protein; 66c1-4-GFP) cultured in vitro or transplanted subcutaneously into the inguinal region of female BALB/c mice to form established tumors. Following in vitro treatment of 66cl-4-GFP cells with α-TEA and suboptimal concentrations of 9-NC, singly or in combination, apoptosis was measured by morphological evaluation of nuclei stained with 4′,6-diamidino-2-phenylindole (DAPI), and DNA synthesis arrest was measured by tritiated thymidine uptake. For in vivo analyses α-TEA and 9-NC, both water-insoluble compounds, were formulated into liposomes using dilauroylphosphatidylcholine and administered by aerosol to deliver doses calculated to be 36 and 0.4 μg/mouse per day, respectively, (singly or each separately for combined treatments) 7 days per week. Treatment of 66cl-4-GFP cells in culture for 3 days with a combination of α-TEA (10 μg/ml; singly produces 38% apoptosis), and suboptimal concentrations of 9-NC (15.6, 31.3, 62.5, or 125 ng/ml; singly produce 2–7% apoptosis), produced 47%, 58%, 64%, and 69% apoptosis. Likewise, combinations of α-TEA + 9-NC inhibited DNA synthesis more than either agent administered singly. A significant reduction (P<0.001) in growth of subcutaneous transplanted tumors was observed with liposome-formulated and aerosolized delivery of α-TEA + 9-NC to BALB/c mice. The incidence of macroscopic lung metastasis was 83% in control vs 8% in α-TEA-, 9-NC-, or combination-treated mice. Fluorescence microscopic examination of lungs and axillary and brachial lymph nodes showed a statistically significant decrease in metastasis observed in α-TEA-, 9-NC-, and combination- vs control-treated animals. Analyses of primary tumor tissue for proliferation and apoptosis showed treatment groups to have lower Ki-67 and higher terminal deoxynucleotidyl transferase-mediated nick end labeling, respectively. Treatments showed no measurable effects on two angiogenesis parameters, namely intratumoral blood volume as assessed by hemoglobin content and intratumoral blood vessel density as assessed with CD31 staining. Combination treatments enhanced antiproliferative and proapoptotic activities in cell culture, and when formulated in liposomes and delivered via aerosolization to treat an aggressive and metastatic syngeneic murine mammary tumor, the combination treatment showed a significant reduction in tumor volume in comparison to either treatment alone. Mechanistically, it appears that neither enhanced apoptosis, reduced cell proliferation, nor reduced blood vessel density can fully account for the enhanced effects of the combination treatment.

ECO-4601 is a structurally novel farnesylated dibenzodiazepinone discovered through DECIPHER® technology, Thallion’s proprietary drug discovery platform. The compound was shown to have a broad cytotoxic activity in the low micromolar range when tested in the NCI 60 cell line panel. In the work presented here, ECO-4601 was further evaluated against brain tumor cell lines. Preliminary mechanistic studies as well as in vivo antitumor evaluation were performed. Since ECO-4601 has a benzodiazepinone moiety, we first investigated if it binds the central and/or peripheral benzodiazepine receptors. ECO-4601 was tested in radioligand binding assays on benzodiazepine receptors obtained from rat hearts. The ability of ECO-4601 to inhibit the growth of CNS cancers was evaluated on a panel of mouse, rat and human glioma cell lines using a standard MTT assay. Antitumor efficacy studies were performed on gliomas (rat and human), human breast and human prostate mouse tumor xenografts. Antitumor activity and pharmacokinetic analysis of ECO-4601 was evaluated following intravenous (IV), subcutaneous (SC), and intraperitoneal (IP) bolus administrations. ECO-4601 was shown to bind the peripheral but not the central benzodiazepine receptor and inhibited the growth of CNS tumor cell lines. Bolus SC and IP administration gave rise to low but sustained drug exposure, and resulted in moderate to significant antitumor activity at doses that were well tolerated. In a rat glioma (C6) xenograft model, ECO-4601 produced up to 70% tumor growth inhibition (TGI) while in a human glioma (U-87MG) xenograft, TGI was 34%. Antitumor activity was highly significant in both human hormone-independent breast (MDA-MB-231) and prostate (PC-3) xenografts, resulting in TGI of 72 and 100%, respectively. On the other hand, IV dosing was followed by rapid elimination of the drug and was ineffective. Antitumor efficacy of ECO-4601 appears to be associated with the exposure parameter AUC and/or sustained drug levels rather than C max. These in vivo data constitute a rationale for clinical studies testing prolonged continuous administration of ECO-4601.

To characterize the pharmacokinetics of oral trametinib, a first in class MEK inhibitor, identify covariates, and describe the relationship between exposure and clinical effects in patients with BRAF V600 metastatic melanoma. Trametinib concentrations obtained in three clinical studies were included in the population pharmacokinetic analysis. Trametinib 2 mg once daily was administered in the Phase 2 and 3 studies. The impact of exposure [trough (C min) or average concentration] on response rates and progression-free survival (PFS) was examined. Plasma concentrations (n = 3120) obtained in 493 patients were described using a two-compartment model. Trametinib oral clearance was lower in women relative to men (1.26-fold) and increased with body weight. There was no significant effect of age, mild or moderate renal impairment, or mild hepatic impairment on oral clearance. Between-subject variability was low (24 %). The number of responders was consistent across median exposure range, although tended to be lower at trough concentration <10 ng/mL. Disease stage was found to be a significant predictor of response with a lower response rate in patients with disease stage of M1c. Lactate dehydrogenase was significant in the analysis of PFS. Patients with observed C min above the median had longer PFS than those below median based on Phase 2 study (median 10.6 ng/mL), while the effect of exposure was not statistically significant in the Phase 3 study (median 13.6 ng/mL). No dosage adjustments are required with any of the covariates tested. Clinical efficacy was associated with trametinib trough concentrations greater than 10 ng/mL.

Multidrug resistance (MDR) is one of the main obstacles in tumor chemotherapy. A promising approach to solving this problem is to utilize a nontoxic and potent modulator able to reverse MDR, which in combination with anticancer drugs increases the anticancer effect. Experiments were carried out to examine the potential of tetrandrine (Tet) as a MDR-reversing agent. Survival of cells incubated with Tet at 2.5 μmol/l for 72 h was over 90%. Tet at 2.5 μmol/l almost completely reversed resistance to vincristine (VCR) in KBv200 cells. Tet at a concentration as low as 0.625 μmol/l produced a 7.6-fold reversal of MDR, but showed no effect on the sensitivity of drug-sensitive KB cells in vitro. In the KBv200 cell xenograft model in nude mice, neither Tet nor VCR inhibited tumor growth. However, VCR and Tet combined inhibited tumor growth by 45.7%, 61.2% and 55.7% in three independent experimental settings. In the KB cell xenograft model in nude mice, Tet did not inhibit tumor growth, but VCR and the combination of VCR and Tet inhibited tumor growth by 40.6% and 41.6%, respectively. Mechanism studies showed that Tet inhibited [3H]azidopine photoaffinity labeling of P-gp and increased accumulation of VCR in MDR KBv200 cells in a concentration-dependent manner. The results suggest that Tet is a potent MDR-reversing agent in vitro and in vivo. Its mechanism of action is via directly binding to P-gp and increasing intracellular VCR accumulation.