CYP17 blockade by abiraterone: further evidence for frequent continued hormone-dependence in castration-resistant prostate cancer.

The limited prognosis of patients with castration-resistant prostate cancer (CRPC) on existing hormonal manipulation therapies calls out for the urgent need for new management strategies. The novel, orally available, small-molecule compound, abiraterone acetate, is undergoing evaluation in early clinical trials and emerging data have shown that the selective, irreversible and continuous inhibition of CYP17 is safe with durable responses in CRPC. Importantly, these efficacy data along with strong preclinical evidence indicate that a significant proportion of CRPC remains dependant on ligand-activated androgen receptor (AR) signalling. Coupled with the use of innovative biological molecular techniques, including the characterisation of circulating tumour cells and ETS gene fusion analyses, we have gained insights into the molecular basis of CRPC. We envision that a better understanding of the mechanisms underlying resistance to abiraterone acetate, as well as the development of validated predictive and intermediate endpoint biomarkers to aid both patient selection and monitor response to treatment, will improve the outcome of CRPC patients.

A feasibility study of sequential doublet chemotherapy comprising carboplatin-doxorubicin and carboplatin-paclitaxel for advanced endometrial adenocarcinoma and carcinosarcoma.

BACKGROUND: Platinum compounds, taxanes and anthracyclines provide the major effective drug classes in the treatment of advanced and recurrent endometrial cancer and carcinosarcoma. PATIENTS AND METHODS: A total of 52 women with advanced or recurrent endometrial cancer and carcinosarcoma were treated with four cycles of carboplatin area under the curve (AUC) 5 and doxorubicin (50 mg/m(2)) for four cycles before or after four cycles of carboplatin AUC5 and paclitaxel (175 mg/m(2)) with each cycle administered at 21-day intervals. RESULTS: Thirty-seven patients (71.2%) completed all planned treatment. Excluding six patients who did not complete treatment for non-drug-related causes, 80.4% completed all planned treatment. Three hundred and seventy-one treatment cycles were administered and 303 (81.7%) occurred on time. Common Toxicity Criteria grade 3/4 haematological toxic effects, particularly neutropenia and thrombocytopenia, were the predominant cause of treatment delays and dose reductions. A low incidence of grade 3 neurotoxicity and no cardiac toxicity were observed. The overall response rates for patients with evaluable disease were 82.1% and 66.7% for endometrial and carcinosarcoma, respectively. At a median follow-up of 21 months, the median progression-free survival for the endometrial adenocarcinoma and carcinosarcoma cohorts were 15.3 and 12.0 months, respectively. CONCLUSION: This regimen is generally well tolerated with encouraging efficacy.

Circulating tumour cell (CTC) counts as intermediate end points in castration-resistant prostate cancer (CRPC): a single-centre experience.

BACKGROUND: The purpose of this study was to evaluate the association of circulating tumour cell (CTC) counts, before and after commencing treatment, with overall survival (OS) in patients with castration-resistant prostate cancer (CRPC). EXPERIMENTAL DESIGN: A 7.5 ml of blood was collected before and after treatment in 119 patients with CRPC. CTCs were enumerated using the CellSearchSystem. RESULTS: Higher CTC counts associated with baseline characteristics portending aggressive disease. Multivariate analyses indicated that a CTC >or=5 was an independent prognostic factor at all time points evaluated. Patients with baseline CTC >or=5 had shorter OS than those with <5 [median OS 19.5 versus >30 months, hazard ratio (HR) 3.25, P=0.012]; patients with CTC >50 had a poorer OS than those with CTCs 5-50 (median OS 6.3 versus 21.1 months, HR 4.1, P<0.001). Patients whose CTC counts reduced from >or=5 at baseline to <5 following treatment had a better OS compared with those who did not. CTC counts showed a similar, but earlier and independent, ability to time to disease progression to predict OS. CONCLUSION: CTC counts predict OS and provide independent prognostic information to time to disease progression; CTC dynamics following therapy need to be evaluated as an intermediate end point of outcome in randomised phase III trials.

A phase I study of daily afatinib, an irreversible ErbB family blocker, in combination with weekly paclitaxel in patients with advanced solid tumours.

BACKGROUND: This phase I study evaluated afatinib, an irreversible ErbB family blocker, plus paclitaxel in patients with advanced solid tumours likely to express human epidermal growth factor receptor (HER1/EGFR) or HER2. METHODS: Oral afatinib was combined with intravenous paclitaxel (80mg/m(2); days 1, 8 and 15 every four weeks) starting at 20mg once daily and escalated to 40 and 50mg in successive cohorts of ⩾3 patients. The primary objective was to determine the maximum tolerated dose (MTD) of afatinib combined with paclitaxel. Secondary objectives included safety, pharmacokinetics and antitumour activity. RESULTS: Sixteen patients were treated. Dose-limiting toxicities with afatinib 50mg were fatigue and mucositis. The MTD was determined as afatinib 40mg with paclitaxel 80mg/m(2), which proved tolerable with repeated dosing. Frequent adverse events (AEs) included diarrhoea (94%), fatigue (81%), rash/acne (81%), decreased appetite (69%) and inflammation of mucosal membranes (69%); no grade 4 treatment-related AEs were observed. Five (31%) confirmed partial responses were observed in patients with non-small cell lung cancer (n=3), oesophageal cancer and cholangiocarcinoma; eight (50%) patients remained on study for ⩾6months. Pharmacokinetic parameters of afatinib and paclitaxel were similar for single administration or in combination. CONCLUSIONS: The MTD and recommended phase II dose of once-daily afatinib combined with paclitaxel 80mg/m(2) (days 1, 8 and 15 every four weeks) was 40mg. AEs at or below this dose were generally manageable with repeated dosing. No pharmacokinetic interactions were observed. This combination demonstrated promising antitumour activity. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00809133.

Dissecting prostate carcinogenesis through ETS gene rearrangement studies: implications for anticancer drug development.

The discovery of ETS gene fusions as common events in prostate cancer represents a paradigmatic shift in the significance attributed to chromosomal translocations as a key mechanistic player in carcinogenesis. However, these chromosomal fusion events are poorly understood, as their functional significance and therapeutic potential remain unclear. Nonetheless, they have generally been used as novel molecular handles to sub-categorise the broad diversity of prostate cancers mainly via the use of fluorescence in-situ hybridisation-based "break-apart assays". Thus, the potential roles of these ETS gene fusion events are being actively explored and are discussed in this review within the context of the existing scientific and clinical climates. Examples include their possible utilities as screening tools, markers for risk stratification and predictors of responses to therapies (in particular hormonal manipulation), biomarkers to guide early phase clinical trials, as well as therapeutic targets. Work is ongoing to address the many questions surrounding these pursuits in a very rapidly evolving area of research, and it is believed that an improved understanding of the biology underpinning these genetic events is vital in order to optimise their use in anticancer drug development.

Clinical outcome and prognostic factors for patients treated within the context of a phase I study: the Royal Marsden Hospital experience.

The main aim of phase I trials is to evaluate the tolerability and pharmacology of a new compound. However, investigating the potential for clinical benefit is also a key objective. Our phase I trial portfolio incorporates a range of new drugs, including molecular targeted agents, sometimes given together with cytotoxic agents. We performed this analysis of response rate, progression-free (PFS) and overall survival (OS) to assess the extent of clinical benefit rate (CBR: partial response (PR)+stable disease (SD)) derived from current trials. We analysed 212 consecutive patients who were treated in 29 phase I studies, from January 2005 to June 2006. All patients had progression of disease prior to study entry. The median age was 58 years (range: 18-86) with a male/female ratio of 2 : 1. A total of 148 patients (70%) were treated in 'first in human trials' involving biological agents (132 patients) or new cytotoxic compounds (16 patients) alone, and 64 patients (30%) received chemotherapy-based regimens with or without biological agents. After a median follow-up time of 34 weeks, the median PFS and OS were 11 and 43 weeks, respectively. The CBR was 53% (9% PR and 44% SD) after the first tumour evaluation after two cycles (between weeks 6 and 8) and has been maintained at 36 and 26% at 3 and 6 months, respectively. Treatment related deaths occurred in 0.47% of our patients and treatment had to be withdrawn in 11.8% of patients due to toxicity. A multivariate analysis (MVA) of 13 factors indicated that low albumin (<35 g l(-1)), lactate dehydrogenase>upper normal limit and >2 sites of metastasis were independent negative prognostic factors for OS. A risk score based on the MVA revealed that patients with a score of 2-3 had a significantly shorter OS compared to patients with a score of 0-1 (24.9 weeks, 95% CI 19.5-30.2 vs 74.1 weeks, 95% CI 53.2-96.2). This analysis shows that a significant number of patients who develop disease progression while receiving standard therapy derived benefit from participation in phase I trials. Risk scoring based on objective clinical parameters indicated that patients with a high score had a significantly shorter OS, and this may help in the process of patient selection for phase I trial entry.