Gemcitabine uptake in glioblastoma multiforme: potential as a radiosensitizer.

Glioblastoma multiforme (GBM), the most frequent malignant brain tumor, has a poor prognosis, but is relatively sensitive to radiation. Both gemcitabine and its metabolite difluorodeoxyuridine (dFdU) are potent radiosensitizers. The aim of this phase 0 study was to investigate whether gemcitabine passes the blood-tumor barrier, and is phosphorylated in the tumor by deoxycytidine kinase (dCK) to gemcitabine nucleotides in order to enable radiosensitization, and whether it is deaminated by deoxycytidine deaminase (dCDA) to dFdU. Gemcitabine was administered at 500 or 1000 mg/m(2) just before surgery to 10 GBM patients, who were biopsied after 1-4 h. Plasma gemcitabine and dFdU levels varied between 0.9 and 9.2 microM and 24.9 and 72.6 microM, respectively. Tumor gemcitabine and dFdU levels varied from 60 to 3580 pmol/g tissue and from 29 to 72 nmol/g tissue, respectively. The gene expression of dCK (beta-actin ratio) varied between 0.44 and 2.56. The dCK and dCDA activities varied from 1.06 to 2.32 nmol/h/mg protein and from 1.51 to 5.50 nmol/h/mg protein, respectively. These enzyme levels were sufficient to enable gemcitabine phosphorylation, leading to 130-3083 pmol gemcitabine nucleotides/g tissue. These data demonstrate for the first time that gemcitabine passes the blood-tumor barrier in GBM patients. In tumor samples, both gemcitabine and dFdU concentrations are high enough to enable radiosensitization, which warrants clinical studies using gemcitabine in combination with radiation.

No evidence of gemcitabine accumulation during weekly administration.

Some anticancer agents tend to accumulate during repeated administration. We determined whether gemcitabine or its metabolites would accumulate during repeated administration. Gemcitabine was administered over two courses with each course consisting of a 30-min infusion at 1000 mg/m(2) weekly for 3 weeks followed by 1 week of rest. In 14 patients we evaluated eventual accumulation by comparing the concentrations in blood samples taken before, and at 30 and 60 min after the start of infusion on days 1, 8 and 15, in both cycles. At the end of the infusion gemcitabine concentrations at day 1 of both courses varied between 18 and 77 microM and at day 15 between 13 and 90 microM. The mean ratios day 8/day 1 and day 15/day 1 varied from 0.94 to 1.18. For the inactive metabolite 2',2'-difluoro-2'-deoxyuridine (dFdU) these values varied between 54 and 152 microM and 55 and 157, respectively, and the ratios from 0.96 to 1.08. The concentration of the active metabolite of gemcitabine, gemcitabine triphosphate (dFdCTP) in peripheral white blood cells, ranged between 37 and 283 pmol/10(6) cells at the end of infusion on day 1 and 35 and 115 pmol/10(6) cells on day 15. Potential accumulation was evaluated using a mixed effects model and no evidence was observed of accumulation for either gemcitabine or its metabolites. Gemcitabine can be administered safely without the risk that the drug will accumulate.

Phase II trial of cisplatin and gemcitabine in patients with advanced gastric cancer.

BACKGROUND: This phase II study was performed to determine the efficacy and toxicity of cisplatin and gemcitabine in patients with advanced gastric cancer. PATIENTS AND METHODS: Forty chemo-naïve patients with measurable locoregionally advanced or metastatic gastric cancer were included; the median patient age was 53 years (range 35-71). Cisplatin was administered at a dose of 50 mg/m2, given in 1 h intravenously (i.v.) on days 1 and 8, followed after 24 h by gemcitabine at a dose of 800 mg/m2 given in 30 min i.v. on days 2, 9 and 16, every 28 days. RESULTS: A median number of four therapy cycles were given (range 2-8). Myelosuppresion was the most important toxicity. Grade 3-4 thrombopenia was observed in 19 patients (48%) and grade 3-4 leukopenia was observed in 23 (58%). Myelotoxicity was cumulative and caused omission of gemcitabine on day 16 in 55% of cycles. Non-haematological toxicity consisted mainly of grade 1-2 nausea and vomiting. Objective responses were observed in 30% of patients including two complete remissions and 10 partial remissions. Median survival was 11 months (range 3-27+). CONCLUSIONS: This cisplatin-gemcitabine regimen had moderate efficacy in patients with advanced gastric cancer, with manageable toxicity. Further studies with this combination may be warranted.

Gemcitabine-radiotherapy in patients with locally advanced pancreatic cancer.

A feasibility study was performed to assess the toxicity and efficacy of a combination of gemcitabine-radiotherapy in patients with locally advanced pancreatic cancer (LAPC). 24 patients (15 females and 9 males) with measurable LAPC were included; the median age of the patients was 63 years (range 39-74 years). The performance status ranged from 0 to 2. Gemcitabine was administered at a dose of 300 mg/m(2), concurrent with radiotherapy, three fractions of 8 Gy, on days 1, 8 and 15. When compliance allowed, gemcitabine alone was continued thereafter, at 1000 mg/m(2), weekly times 3, every 4 weeks, depending on the response and toxicity. All patients were evaluable for toxicity and response. The objective response rate was 29.2% (1 complete remission+6 partial remissions); 12 patients had stable disease. However, 2 of the radiological partial remissions were shown to be complete remissions by pathology assessment. Median duration of response was 3 months (range 1-35+months). Median time to progression was 7 months (range 2-37+months). Median survival was 10 months (range 3-37+months). Dose reduction or omission of gemcitabine was necessary in 10 patients. Non-haematological toxicity consisted of 87.5% nausea and vomiting grade I-II, diarrhoea 54%, ulceration in stomach and duodenum 37.5% (20.8% ulceration with bleeding); 1 patient developed a fistula between the duodenum and aorta, 5 months after treatment. Anaemia grade III-IV was observed in 8.3% of the patients. Neutropenia grade III-IV was observed in 8.3%, thrombocytopenia grades III-IV in 16.7%. In 1 patient who underwent resection postchemoradiation, no viable tumour cells were found. In addition, in the patient who suddenly died of a fistula between the duodenum and aorta, no viable tumour cells were detectable at autopsy. Although the toxicity of this treatment was occasionally severe, the response and survival are encouraging and warrant further studies of this combination.

[Team care: a necessity for a child with HIV infection]. / Teamzorg: een noodzaak voor het met HIV geïnfecteerde kind.

In four children, a boy aged 2.5 years, a girl of 4, her brother of 7 years and a girl aged 10 months, HIV infection was diagnosed. Since 1996 HIV-infected children in the Netherlands are treated with a combination of two nucleoside analogs and a protease-inhibitor. This therapy improves the quality of life, increases the life expectancy of HIV-infected children and is generally well tolerated. However, the current combination therapy is complex and puts a burden on the child and the family. Therefore, long term compliance will be difficult. Moreover, the majority of the families have extremely difficult social circumstances which interfere with an optimal medical treatment for the child. The parents of three of the children were refugees from African countries. Intensive support of the family by a team of health care and social workers is usually necessary to make antiretroviral combination therapy possible. Care directed at the individual needs of the child and family is crucial to help this vulnerable group of children and families in our society.