[Molecular bases of platinum-resistance in testicular cancer]. / Bases moleculares de la resistencia a cisplatino en cáncer de testículo.

Cisplatin has been the cornerstone of germ cell testicular tumors therapy since its introduction more tan 30 years ago, and a basic part of the schemes given to multiple ovarian, lung, head and neck, and bladder tumors among others. Some tumors present primary resistance to this drug, others will develop it despite good initial response. In the case of testicular germ cell tumors most of them are very sensitive to this drug but up to 20% of patients with metastatic disease will present resistance, most of them secondary after a very good initial response. Cisplatin acts by binding to DNA to activate genetic damage recognition mechanisms and apoptosis through the mitochondrial pathway. Resistance mechanisms to cisplatin have been classified in those that happen (1) before its binding to DNA and (2) once it binds to DNA. Most advances in their discovery have used other neoplasias as models, mainly ovarian and lung tumors. In this review we will describe the biological mechanisms behind resistance to cisplatin from the global perspective but trying to focus in testicular germ cell tumors.

A phase I clinical and pharmacokinetic study of paclitaxel and docetaxel given in combination in patients with solid tumours.

The aim of this study was to determine the safety and feasibility profile of paclitaxel (PTX) and docetaxel (DTX) in combination and the pharmacokinetic and pharmacodynamic interaction between these two drugs in two different alternated sequences of administration. The starting dose was PTX (100 mg/m(2)) as a 3-h IV infusion followed by DTX (50 mg/m(2)) as 1-h IV infusion or the alternative sequence in every other patient. The sequence was alternated in the second course in each patient treated. Cycle duration was 21 days. Twenty patients received 103 cycles of treatment through three dose levels. Febrile neutropenia and grade 4 neutropenia lasting longer than 7 days were dose-limiting and defined the toxic dose of DTX (50 mg/m(2)) and PTX (135 mg/m(2)) in patients with prior treatment and the recommended dose in patients without prior treatment. Non-hematological toxicities included asthenia, neuropathy, arthralgia/myalgia and stomatitis. Pharmacokinetics of DTX were significantly affected by the sequence. Nadir ANC was more profound when DTX was administered first (P=0.022). There were one complete response and six partial responses, giving an overall response rate of 35%. DTX (50 mg/m(2)) followed by PTX (135 mg/m(2)) can be administered safely and it is an active regimen. The pharmacokinetics of PTX are not influenced by DTX but DTX pharmacokinetics depend on the sequence of administration, which influences its haematological toxicity profile.

Phase II multicentre study of temozolomide in combination with interferon alpha-2b in metastatic malignant melanoma.

OBJECTIVE: Temozolomide is a novel oral alkylating agent, active against metastatic melanoma. Combinations of chemotherapy and biological response modifiers have been associated with increased antitumour activity. A multicentre phase II study was performed to assess the activity and toxicity of temozolomide in combination with interferon alpha-2b. PATIENTS AND METHODS: Eligible patients had histologically confirmed metastatic melanoma. Previously untreated patients received temozolomide administered orally at a dose of 150 mg/m/day for 5 days every 4 weeks, in combination with interferon given continuously subcutaneously twice a week at a dose of 10 MU/m. Treatment continued until disease progression or for a maximum of 12 months. RESULTS: From June 1999 to August 2002, 27 eligible patients were included in the study at six centres. Median age was 59 (28-77) years; 17 male and 10 female patients were recruited; the median Karnofsky performance score was 90 (70-100); three patients had received prior adjuvant interferon; the majority of patients had fewer than three involved sites. A total of 96 cycles were administered; there were one complete response, four partial response and five stable disease (overall response rate: 18.5%, 95% confidence interval: 6.3-38.1). All responses were seen in patients with exclusively lymph node and pulmonary disease [M1a (one patient); M1b (four patients)]. The median response duration was 6.9 months. One patient remains in complete remission at 4 years. The median time to progression and the median survival were 1.87 and 9.5 months, respectively. Haematological toxicity was neutropenia G-IV: 1, G-III: 4, thrombocytopenia G-III: 2, and anaemia G-III: 2. Predominant non-haematological toxicity was hepatotoxicity G-III: 4. Other toxicities were mild or moderate. Dose reduction was required for nine cycles of interferon, one of temozolomide and two of both drugs. CONCLUSIONS: Temozolomide in combination with interferon is a well-tolerated palliative regimen that has moderate activity against metastatic melanoma. Further evaluation of this regimen in comparative studies or in combination with other drugs is warranted.

Pre-clinical validation of early molecular markers of sensitivity to aromatase inhibitors in a mouse model of post-menopausal hormone-sensitive breast cancer.

INTRODUCTION: Changes in breast cancer cell biology following hormonal treatment have been claimed as promising predictor markers of clinical benefit even outperforming clinical response. From previous work we selected 10 genes showing both a well known regulation by oestrogen and a high level of early transcriptional regulation following therapy with aromatase inhibitors. Here we use an animal breast cancer model to explore the feasibility of the determination of their expression in minimally invasive samples and to further assess the magnitude of their regulation by letrozole. ANIMAL AND METHODS: Aromatase inhibitor sensitive breast cancer tumours were grown in athymic mice under supplement with androstenedione. Following initial tumour growth animals were assigned to a control group or to receive letrozole at two different dosages. Fine needle aspirates were obtained at the moment of treatment assignation and one week later. Expression of the following genes at both time points was determined: Ki-67, Cyclin D1, pS2, Trefoil Factor 3, PDZ domain containing 1, Ubiquitin-conjugating enzyme E2C, Stanniocalcin 2, Topoisomerase 2 alfa, MAN1A1 and FAS. RESULTS: Fine needles aspirates were found to be a feasible and reproducible technique for RNA extraction. Trefoil Factor 3, pS2, Cyclin D1 and Stanniocalcin 2 were significantly downregulated by letrozole. Among them pS2 appears to be most sensitive to aromatase inhibitor treatment even differentiating sub-optimal from optimal letrozole dosage. DISCUSSION: We present pre-clinical evidence to justify the exploration in clinical trials of pS2, Trefoil factor 3, Cyclin D1 and Stanniocalcin as dynamic markers of oestrogen-driven pathway activation.