P. de Souza

Multicentre phase I/II study of PI-88, a heparanase inhibitor in combination with docetaxel in patients with metastatic castrate-resistant prostate cancer

BACKGROUND Docetaxel (Taxotere) improve survival and prostate-specific antigen (PSA) response rates in patients with metastatic castrate-resistant prostate cancer (CRPC). We studied the combination of PI-88, an inhibitor of angiogenesis and heparanase activity, and docetaxel in chemotherapy-naive CRPC. PATIENTS AND METHODS We conducted a multicentre open-label phase I/II trial of PI-88 in combination with docetaxel. The primary end point was PSA response. Secondary end points included toxicity, radiologic response and overall survival. Doses of PI-88 were escalated to the maximum tolerated dose; whereas docetaxel was given at a fixed 75 mg/m(2) dose every three weeks RESULTS Twenty-one patients were enrolled in the dose-escalation component. A further 35 patients were randomly allocated to the study to evaluate the two schedules in phase II trial. The trial was stopped early by the Safety Data Review Board due to a higher-than-expected febrile neutropenia of 27%. In the pooled population, the PSA response (50% reduction) was 70%, median survival was 61 weeks (6-99 weeks) and 1-year survival was 71%. CONCLUSIONS The regimen of docetaxel and PI-88 is active in CRPC but associated with significant haematologic toxicity. Further evaluation of different scheduling and dosing of PI-88 and docetaxel may be warranted to optimise efficacy with a more manageable safety profile.

Predictive and prognostic biomarkers for neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Locally advanced rectal cancer is regularly treated with trimodality therapy consisting of neoadjuvant chemoradiation, surgery and adjuvant chemotherapy. There is a need for biomarkers to assess treatment response, and aid in stratification of patient risk to adapt and personalise components of the therapy. Currently, pathological stage and tumour regression grade are used to assess response. Experimental markers include proteins involved in cell proliferation, apoptosis, angiogenesis, the epithelial to mesenchymal transition and microsatellite instability. As yet, no single marker is sufficiently robust to have clinical utility. Microarrays that screen a tumour for multiple promising candidate markers, gene expression and microRNA profiling will likely have higher yield and it is expected that a combination or panel of markers would prove most useful. Moving forward, utilising serial samples of circulating tumour cells or circulating nucleic acids can potentially allow us to demonstrate tumour heterogeneity, document mutational changes and subsequently measure treatment response.

Phase II study of gemcitabine and oxaliplatin in patients with recurrent ovarian cancer: an Australian and New Zealand Gynaecological Oncology Group study

Gemcitabine and oxaliplatin have shown single-agent activity in relapsed ovarian cancer. This combination was used to determine response rates, time-to-event efficacy measures, and toxicity in patients with recurrent ovarian cancer. Patients with prior platinum-based chemotherapy who had measurable lesions and/or elevated CA-125 levels were identified as group A (platinum-refractory/platinum-resistant patients) and group B (platinum-sensitive patients). All patients received gemcitabine 1000 mg/m2 on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8 every 21 days for up to eight cycles. Seventy-five patients (21 in group A and 54 in group B), with a median age of 58 years (range, 37–78), were enrolled. A median of six cycles (range, 1–8) was administered. By intent-to-treat analysis, 15 patients with measurable disease achieved partial response for an overall best response rate of 20.0% (9.5% in group A and 24.1% in group B). CA-125 response was observed in 48.4% patients (30.0% in group A and 57.1% in group B). Median time to progressive disease was 7.1 months (95% CI, 5.6–9.0 months) with 5.0 months in group A and 8.3 months in group B. Median overall survival was 17.8 months (95% CI, 12.9–21.3 months) with 9.2 months for group A and 20.0 months for group B. Major grade 3/4 toxicities were neutropenia (61.3%), leukopenia (24.0%), nausea (16.0%), and vomiting (22.7%). We conclude that the combination of oxaliplatin and gemcitabine is active in patients with recurrent ovarian cancer, but the regimen is unsatisfactory for further study due to modest response and relatively high toxicity.

Upregulated Polo-Like Kinase 1 Expression Correlates with Inferior Survival Outcomes in Rectal Cancer.

Background Human polo-like kinase 1 (PLK1) expression has been associated with inferior outcomes in colorectal cancer. Our aims were to analyse PLK1 in rectal cancer, and its association with clinicopathological variables, overall survival as well as tumour regression to neoadjuvant treatment. Methods PLK1 expression was quantified with immunohistochemistry in the centre and periphery (invasive front) of rectal cancers, as well as in the involved regional lymph nodes from 286 patients. Scores were based on staining intensity and percentage of positive cells, multiplied to give weighted scores from 1–12, dichotomised into low (0–5) or high (6–12). Results PLK1 scores in the tumour periphery were significantly different to adjacent normal mucosa. Survival analysis revealed that low PLK1 score in the tumour periphery had a hazard ratio of death of 0.59 in multivariate analysis. Other predictors of survival included age, tumour depth, metastatic status, vascular and perineural invasion and adjuvant chemotherapy. There was no statistically significant correlation between PLK1 score and histological tumour regression in the neoadjuvant cohort. Conclusion Low PLK1 score was an independent predictor of superior overall survival, adjusting for multiple clinicopathological variables including treatment.

Circulating tumour cells and circulating nucleic acids as a measure of tumour dissemination in non-metastatic colorectal cancer surgery.

There is accumulating evidence for circulating tumour cells (CTCs) and circulating tumour nucleic acids (ctNAs) as prognostic and predictive biomarkers in colorectal cancer. Their role in the perioperative setting is evolving. These blood-borne biomarkers can potentially demonstrate tumour dissemination at time of colorectal cancer surgery and estimate the completeness of a surgical resection. CTCs and circulating ctNA levels at time of surgery, and persistent levels post-surgery, may correlate with poorer patient outcomes. These biomarkers can be utilised to refine surgical techniques to minimise tumour dissemination and determine the need for adjuvant therapy.

Phase II study of carboplatin followed by sequential gemcitabine and paclitaxel as first-line treatment for advanced ovarian cancer

The aim of this exploratory phase II study was to evaluate sequential chemotherapy with carboplatin followed by gemcitabine–paclitaxel combination in chemonaive patients with advanced ovarian cancer. The primary objective was to evaluate time to progressive disease (TTPD); secondary objectives included the evaluation of 1- and 3-year survival, response rates, and toxicity. Following initial debulking surgery or biopsy, patients with FIGO stage IIC–IV disease received four cycles of carboplatin area under the curve (AUC) 6 (day 1) every 21 days, followed by four cycles of gemcitabine 1000 mg/m2 (days 1 and 8) and paclitaxel 175 mg/m2 (day 8) every 21 days. A total of 47 patients enrolled, 44 (93.6%) completed the initial four cycles, and 39 patients (82.9%) completed the planned eight cycles. The median and maximum lengths of follow-up were 31.2 and 43.7 months, respectively. Median TTPD was 13.8 months (95% CI, 11.6–21.0 months), and median survival time was 31.2 months (95% CI, 25.2–39.6 months). Survival at 1 and 3 years was 95.7% and 44.2%, respectively. Of the 43 evaluable patients, most (95.3%) of them achieved a CA-125 marker response based on Gynecologic Cancer Intergroup (GCIG) definition. The partial response rate in the seven patients with measurable disease was 46.4%. Myelosuppression was the major toxicity, with grade 3 and 4 neutropenia observed in 76.6% patients and thrombocytopenia in 12.8% patients. The sequential approach of carboplatin followed by gemcitabine–paclitaxel as first-line treatment for patients with ovarian cancer is feasible and well tolerated, and depending upon the findings from other major trials, it may merit further evaluation.

Enhancement of the activity of phenoxodiol by cisplatin in prostate cancer cells

Phenoxodiol is a novel isoflav-3-ene, currently undergoing clinical trials, that has a broad in vitro activity against a number of human cancer cell lines. Phenoxodiol alone inhibited DU145 and PC3 in a dose- and time-dependent manner with IC50 values of 8±1 and 38±9 μM, respectively. The combination of phenoxodiol and cisplatin was synergistic in DU145, and additive in PC3, as assessed by the Chou–Talalay method. Carboplatin was also synergistic in combination with phenoxodiol in DU145 cells. The activity of the phenoxodiol and cisplatin combination was confirmed in vivo using a DU145 xenograft model in nude mice. Pharmacokinetic data from these mice suggest that the mechanism of synergy may occur through a pharmacodynamic mechanism. An intracellular cisplatin accumulation assay showed a 35% (P<0.05) increase in the uptake of cisplatin when it was combined in a ratio of 1 μM: 5 μM phenoxodiol, resulting in a 300% (P<0.05) increase in DNA adducts. Taken together, our results suggest that phenoxodiol has interesting properties that make combination therapy with cisplatin or carboplatin appealing.