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Objective: To investigate the prevalence and characteristics of gemcitabine-based chemotherapy-induced thrombocytopenia in Chinese patients with nonsmall cell lung cancer (NSCLC)., Materials and Methods: Medical records of 197 patients with histologically proven NSCLC received gemcitabine-based chemotherapy from June 2011 to June 2013 in our hospital were collected. The relative risk factors were identified and evaluated by univariate and multivariate analyses., Results: The incidence of gemcitabine-based chemotherapy-induced thrombocytopenia in these NSCLC patients was 85.8%. Between thrombocytopenia and nonthrombocytopenia patients, in patients with thrombocytopenia and thrombocytopenia, we found Stage III/IV patients got more probabilities for thrombocytopenia (P < 0.01). In addition, patients who received gemcitabine and cisplatin (GP) regimen resulted in more thrombocytopenia than gemcitabine and carboplatin (GC) and other regimens (P < 0.001). In addition, majority of the thrombocytopenia patients presented thrombocytopenia in their first cycle (P < 0.001). Whereas, other potential risk factors such as age, gender, performance status value, diabetes mellitus or not, and other underlying disease (hypertension and hepatopathy) were not showed such significance in this study. Further, the multivariate analysis revealed that stage (odds ratio [OR] 7.113, P < 0.01) and chemotherapy cycles (OR 0.543, P < 0.01) were also statistically significant independent risk factors for gemcitabine-based chemotherapy-induced thrombocytopenia., Conclusion: This study shows that thrombocytopenia is common in Chinese NSCLC patients receiving gemcitabine-based regimens. Chemotherapy cycles and stage might be the important factors influencing the occurrence of gemcitabine-based regimens-induced thrombocytopenia., Competing Interests: There are no conflicts of interest

The Bcl-2 antagonist ABT-737 targets Bcl-2/Bcl-xL, but not Mcl-1, which may confer resistance to this agent in various cancers with high levels of Mcl-1. Here, we showed that the combination of gemcitabine and ABT-737 exhibited synergistic cytotoxicity and induced significant apoptosis in multiple cancer types, including lung, renal, bladder, and prostate cancers. The enhanced apoptosis induced by gemcitabine plus ABT-737 was accompanied by the greater extent of mitochondrial depolarization, caspases-3 activation, and PARP cleavage in 95-D and 5637 cell lines. Importantly, in ABT-737-resistant cancer cells, the interaction between USP9X and Mcl-1, which was increased by ABT-737 treatment, could be disrupted by gemcitabine, thus resulting in enhanced ubiquitination and the subsequent degradation of Mcl-1 and ultimately in the synergism of these two drugs. Moreover, the increased anticancer efficacy of gemcitabine combined with ABT-737 was further validated in a human lung cancer 95-D xenograft model in nude mice. Taken together, our data first showed the synergistic anticancer capabilities achieved by combining gemcitabine and ABT-737 and, second, opened new opportunities to use antiapoptotic Bcl-2 family members, which drive tumor cell resistance in current anticancer therapies, therapeutically., (© 2011 American Association for Cancer Research.)

Aim: To investigate the pharmacodynamics and pharmacokinetics of gemcitabine (dFdC) administered on d 1 and 5 plus cisplatin administered on d 1 in chemonaive patients with stage IIIB or IV non-small cell lung cancer (NSCLC)., Methods: In each combination cycle, gemcitabine was administered at a dose of 1250 mg/m(2) as a 30 min intravenous (iv) infusion on d 1 and 5 followed by cisplatin at a dose of 75 mg/m(2) as a 3 h iv infusion on d 1 every 3 weeks. There was an interval of 1 h between the two infusions. Clinical response and toxicity of the regimen were observed. Furthermore, the plasma concentrations of gemcitabine (dFdC) and its metabolite (dFdU) at different time points were detected during the first cycle of infusion. Pharmacokinetic software (PKS) was used to estimate the pharmacokinetic parameters of gemcitabine and its metabolite dFdU., Results: A total of 28 patients was enrolled in the study. The median age was 54 years (range 27-75 years), and most patients were in good clinical condition. Twenty-seven patients received two or more treatment cycles. The overall clinical response rate was 33.3%. The median overall survival time was 13 months. The estimated median time to tumor progression (TTP) was 6.2 months, and the 1-year survival rate was 55.6%. Toxicities were tolerated. The main toxicity was myelosuppression; 35.7% of patients had grade 3/4 hematologic toxicities and 28.6% had grade 3/4 non-hematologic toxicities, which were commonly gastrointestinal responses. The pharmacokinetic parameters of dFdC and dFdU were not different between pre- and post-administration of gemcitabine on d 1 and 5. dFdU was minimal (0.729+/-0.637 microg/mL) before gemcitabine was infused on d 5, and gemcitabine was not present., Conclusion: The regimen is active and well tolerated in chemonaive patients with advanced NSCLC. After gemcitabine was administered on d 1 and 5, the pharmacokinetic parameters of dFdC and dFdU showed no difference from those before the infusion, and dFdU was minimal before gemcitabine was administered on d 5.

Aim: To establish a high-pressure liquid chromatography (HPLC) method for determination of the concentration of gemcitabine (dFdC) and its metabolite (dFdU) in human plasma., Methods: Plasma 1.0 mL spiked with floxuridine as an internal standard was extracted with 3.0 mL of methanol-acetonitrile (v/v, 1:9). The supernatant was evaporated at 60 centigrade and the residue was reconstituted with 0.5 mL of the solution used as the mobile phase. After centrifugation, 50 microL of the supernatant was injected into the HPLC system. Separation was achieved on a C18 (4.6 mm multiply 50 mm, 5 microm) column at 25 centigrade with the flow rate of the mobile phase set to 0.8 mL/min. The compounds were detected at 268 nm. The mobile phase consisted of 40.0 mmol/L acetate ammonium buffer solution (pH 5.5) and acetonitrile (v/v, 97.5:2.5)., Results: The linear range was 0.20-10.0 mg/L (r=0.9999) for dFdC and 0.50-50.0 mg/L (r=0.9999) for dFdU. The limit of detection (LOD) was 0.10 mg/L for dFdC and 0.25 mg/L for dFdU, while the limit of quantification (LOQ) was 0.20 mg/L (RSD<10 %) for dFdC and 0.50 mg/L (RSD<3 %) for dFdU. The average recovery of dFdC and dFdU by this method were 103.3 % and 98.7 %, respectively. For intra-day and inter-day, the corresponding standard deviations of the measurements of dFdC and dFdU were both less than 5.5 %., Conclusion: An analytical method was established to measure the concentrations of dFdC and dFdU in human plasma and was effectively applied to the dFdC and dFdU pharmacokinetic studies of 8 Chinese patients with malignant tumors.