A phase I study of prolonged ambulatory infusion carboplatin with oral etoposide showing activity in prostate cancer

Anti-tumour activity of platinum compounds in advanced prostate cancer-a systematic literature review

BACKGROUND

For men with advanced castration-resistant prostate cancer (CRPC), several treatment options are available, including androgen receptor (AR) pathway inhibitors (abiraterone acetate, enzalutamide), taxanes (docetaxel, cabazitaxel) and the radionuclide (radium-223). However, cross-resistance is a clinically relevant problem. Platinum compounds have been tested in a number of clinical trials in molecularly unselected prostate cancer patients. Advances in CRPC molecular profiling have shown that a significant proportion of patients harbour DNA repair defects, which may serve as predictive markers for sensitivity to platinum agents.

OBJECTIVE

To systematically identify and analyse clinical trials that have evaluated platinum agents in advanced prostate cancer patients.

METHODS

PubMed was searched to identify published clinical trials of platinum agents in advanced prostate cancer. The PRIMSA statement was followed for the systematic review process. Identified trials are analysed for study design, statistical plan, assessments of anti-tumour activity and the potential value of predictive biomarkers.

RESULTS

A total of 163 references were identified by the literature search and 72 publications that met the selection criteria were included in this review; of these 33 used carboplatin, 27 cisplatin, 6 satraplatin, 4 oxaliplatin and 2 other platinum compounds. Overall, anti-tumour activity varies in the range of 10%-40% for objective response and 20%-70% for PSA decline ≥50%. Response seemed highest for the combinations of carboplatin with taxanes or oxaliplatin with gemcitabine. The interpretation of the clinical data is limited by differences in response criteria used and patient populations studied.

CONCLUSION

Platinum compounds have moderate anti-tumour activity in molecularly unselected patients with advanced prostate cancer. Translational evidence of DNA repair deficiency should be leveraged in future studies to select prostate cancer patients most likely to benefit from platinum-based therapy.

Isoxazole derivatives of 6-fluoro-N-(6-methoxybenzo[d]thiazol-2-yl)benzo[d]thiazol-2-amine and N-(pyrimidin-2-yl)benzo[d]thiazol-2-amine: regulation of cell cycle and apoptosis by p53 activation via mitochondrial-dependent pathways

The compounds depicted were shown to induce DNA damage and activate p53, which in turn activates Bax and decreases Bcl2 levels. This resulted in apoptosis in Colo205 cells.

Phase II study of prolonged ambulatory infusion carboplatin and oral etoposide for patients progressing through hormonal therapy for prostate cancer

AIM

To develop a well-tolerated outpatient chemotherapy regimen for hormone-insensitive prostate cancer.

METHOD

Forty patients received carboplatin 20 mg/m2 by continuous ambulatory infusion with oral etoposide 50 mg/day for 21 days repeated every 6 weeks.

RESULTS

Four patients had a partial response and 16 patients had stable disease. Two of the partial responders and three additional patients recorded falls in prostate specific antigen of 50% or more. The median freedom from progression was 24 weeks and median survival 32 weeks. Twenty-four of 31 patients had decreasing pain scores and 20 of 34 patients recorded improved quality of life with at least one cycle of treatment. The main toxicity occurred in seven patients with World Health Organization (WHO) grade 4 neutropenia and in four patients with WHO grade 3 neutropenia. Only one patient developed febrile neutropenia. Six patients had grade 3 anaemia and three patients had grade 3 thrombocytopenia. Two patients reported grade 3 lethargy whereas 11 patients had grade 2 lethargy.

CONCLUSION

This was a well-tolerated regimen that improved symptomatic control of hormone-insensitive prostate cancer.

Enhanced transgene expression in androgen independent prostate cancer gene therapy by taxane chemotherapeutic agents

PURPOSE

Chemotherapy is often used as a primary therapy for metastatic cancer because it kills cells en masse. However, high doses of chemotherapeutic drugs can cause toxicity in nontarget organs. Gene therapy may provide a better alternative to chemotherapy because its targeting of specific genes may reduce the undesirable toxicity associated with chemotherapy. We evaluated whether the chemotherapeutic agent docetaxel or paclitaxel may be combined with gene therapy to create a new therapeutic regimen for metastatic androgen independent prostate cancer.

MATERIALS AND METHODS

The 2 androgen independent prostate cancer cell lines PC-3 and DU 145 were treated with docetaxel or paclitaxel. Three recombinant adenoviruses containing p21WAF-1/CIP1, p53 protein or beta-galactosidase complementary DNA under the control of cytomegalovirus promoter were used to determine transgene expression. They were evaluated by Western blot analysis, beta-galactosidase activity or in vitro growth assays. The [(3)H] labeled E1 deleted adenovirus dl312 was used to determine adenovirus uptake into cells.

RESULTS

Docetaxel and paclitaxel enhanced adenovirus mediated transgene expression. Docetaxel appears to be a more potent growth inhibitor in vitro. Elevated transgene expression in virus infected cells induced by these 2 drugs was produced by increased cytomegalovirus promoter activity rather than increased virus uptake.

CONCLUSIONS

The potential synergy of gene therapy with docetaxel and paclitaxel may be an important direction for future therapy for metastatic androgen independent prostate cancer.