Pharmacokinetic and pharmacodynamic properties of an oral formulation of the histone deacetylase inhibitor Belinostat (PXD101).

PURPOSE: The primary objective of this sub-study, undertaken as an extension to the previously reported phase-I study, was to explore the feasibility, tolerability and pharmacokinetics (PK) of belinostat when administered by the oral route. Preliminary pharmacodynamic (PD) studies were also performed to enable comparison of the biological effects of the oral and intravenous formulations. PATIENTS AND METHODS: Oral belinostat was administered in a range of doses and schedules (once, twice or thrice daily), on either day 1 or days 1-5, of the second or a subsequent treatment cycle in 15 patients who were included in the phase-I trial of intravenous belinostat. Serial blood samples were collected for PK and PD (histone acetylation) analyses, and the results compared with corresponding analyses following intravenous administration. RESULTS: A total mean daily AUC of 2,767 ± 1,453 ng h/ml (8.7 ± 4.6 µM h) resulted from a dose of 1,000 mg/m(2) once daily (qd). There was no clear evidence of drug accumulation on twice daily dosing (bid); however, a trend towards accumulation was apparent when belinostat was given three times daily (tid). Mean half-life (T½) of a single dose of 1,000 mg/m(2) was 1.5 h (± 0.3 h) and peak levels were reached in an average of 1.9 h (± 0.3 h). The half-life was found to be independent of dose, but a trend towards increasing half-life following multiple dosing was observed. Histone H4 hyperacetylation in PBMCs estimated after oral dosing was comparable to that achieved after intravenous administration. CONCLUSIONS: High doses of oral belinostat, up to 1,000 mg/m(2) bid for 5 consecutive days, have been tolerated in this small study. An oral formulation could lead to enhanced drug exposure and, more importantly, prolonged effects on the intended drug target. Future trials are required to establish the optimal dose and schedule of oral administration of belinostat.

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.

Participation of patients with gynecological cancer in phase I clinical trials: two years experience in a major cancer center.

OBJECTIVES: This study aims at analyzing the clinico-demographic features that influence the recruitment of gynecological cancer (GC) patients to phase I trials. The possible clinical benefit to patients resulting from the participation in these trials has been also investigated. METHODS: We performed a retrospective analysis of GC patients referred to the Phase I Unit of the Royal Marsden Hospital in Sutton (Surrey, UK), over 2 years. RESULTS: Overall 68 GC patients were referred, and subsequently 32 (47.1%) enrolled. The percentage of patients enrolled increased as the distance to travel between the patient's residence and the hospital shortened (8.3% through 47.8% to 60.8%, for travel time >2, 1-2 or < or =1 h, respectively; p=0.008). Better performance status (PS) was found to be associated with higher enrollment rate with percentages increasing from 0 through 51.2 to 58.8 in cases with PS> or =2, PS=1, PS=0, respectively (p=0.015). Among the biochemical parameters, only hepatobiliary dysfunction was found to be associated with lower enrollment (p=0.012). Minimal response/disease stabilization was observed in 11 patients (34.4%). An increased median survival following the first visit was observed in patients enrolled compared to those not enrolled (8 versus 4 months, respectively, p=0.0055). In the multivariate analysis, only PS and enrollment in trials retained an independent prognostic role (p=0.031 and p=0.040, respectively). CONCLUSIONS: This study, suggesting liver function and PS as important factors influencing the recruitment of GC patients to phase I trials could guide referral of patients to phase I Units. Moreover, the practical limitations imposed by long distance travel, together with the potential clinical benefit due to the participation to these trials, should encourage more investigators to develop phase I units in major cancer centers.

Improving the outcome of patients with castration-resistant prostate cancer through rational drug development.

Castration-resistant prostate cancer (CRPC) is now the second most common cause of male cancer-related mortality. Although docetaxel has recently been shown to extend the survival of patients with CRPC in two large randomised phase III studies, subsequent treatment options remain limited for these patients. A greater understanding of the molecular causes of castration resistance is allowing a more rational approach to the development of new drugs and many new agents are now in clinical development. Therapeutic targets include the adrenal steroid synthesis pathway, androgen receptor signalling, the epidermal growth factor receptor family, insulin growth factor-1 receptor, histone deacetylase, heat shock protein 90 and the tumour vasculature. Drugs against these targets are giving an insight into the molecular pathogenesis of this disease and promise to improve patient quality of life and survival. Finally, the recent discovery of chromosomal translocations resulting in the upregulation of one of at least 3 ETS genes (ERG, ETV1, ETV4) may lead to novel agents for the treatment of this disease.

A phase I study of intravenous TZT-1027 administered on day 1 and day 8 of a three-weekly cycle in combination with carboplatin given on day 1 alone in patients with advanced solid tumours.

BACKGROUND: TZT-1027 is a tubulin-binding drug and synthetic derivative of dolastatin-10 with cytotoxic and antivascular activity in vitro and in vivo. Studies have demonstrated anti-tumour activity in several tumour types. METHODS: Patients were treated with escalating doses of TZT-1027 and carboplatin at doses from 1.6 to 2.0 mg/m2 and AUC 4 and 5 respectively. For pharmacokinetic analysis, plasma sampling was done during the first course using a high-performance liquid chromatographic assay. RESULTS: 14 patients received a total of 55 cycles at three dose levels. Dose limiting toxicities (DLTs) were first observed with 1.6 mg/m2 TZT-1027 and carboplatin AUC 5; 1 patient had grade 4 neutropenia and a delay in day 8 treatment occurred in two patients (gr 2 fatigue, gr 3 diarrhoea). At TZT-1027 2 mg/m2 and carboplatin AUC 5, one patient experienced grade 3 paralytic ileus. The most frequent toxicities were neutropenia, anaemia, fatigue, constipation, infection and vomiting. Peripheral neuropathy was reported in 36% of patients. One patient (pancreatic adenocarcinoma) achieved a partial response lasting 181 days. Pharmacokinetic analysis did not demonstrate any interaction between TZT-1027 and carboplatin. CONCLUSIONS: The recommended phase II dose is TZT-1027 1.6 mg/m2 and carboplatin AUC 5. No evidence of a PK interaction between these agents was observed.

Phase II study of docetaxel in patients with relapsed or refractory malignant lymphoma.

We report the activity and toxicity of docetaxel in 12 evaluable heavily pretreated patients with relapsed and refractory non-Hodgkin's lymphoma and Hodgkin's disease. In all, 42% achieved a partial response, 25% achieved stable disease. Median duration of response was 16 (10-21) weeks. The median overall survival was 70 (9-178) weeks and for responders it was 120 (22-178) weeks. One patient developed one episode of neutropenic sepsis. Docetaxel has limited activity in this group of patients.

Adjuvant therapy of malignant melanoma.

High risk surgically resected melanoma is associated with a less than 50% 5-year survival. Adjuvant therapy is an appropriate treatment modality in this setting, and is more likely to be effective as the tumour burden here is small. Clinical observations of spontaneous tumour regressions and a highly variable rate of disease progression suggest a role of the immune system in the natural history of melanoma. Biological agents have therefore been the subjects of numerous adjuvant studies. Early, randomised controlled trials (RCTs) of Bacillus Calmette-Guerin (BCG), levamisole, Corynebacterium parvum, chemotherapy, isolated limb perfusion (ILP), radiotherapy, transfer factor (TF), megestrol acetate and vitamin A yielded largely negative results. Current trials focus on vaccines and the interferons. To date the latter is the only therapy to have shown a significant benefit in the prospective randomised controlled phase III setting. This report represents a systematic review of studies in adjuvant therapy in melanoma. Data from ongoing studies is awaited before a role for adjuvant agents in high risk melanoma is confirmed.

Gender and survival in malignant tumours.

BACKGROUND: Epidemiological evidence supports the existence of a survival advantage for female patients with melanoma. This survival advantage often persists when other prognostic variables are taken into account. The basis for this female advantage or male disadvantage is not established although female sex steroids can retard melanoma invasion in vitro. DESIGN: In considering the mechanisms involved, we have examined the literature to establish whether this female survival advantage is shared by other solid tumours. The tumours selected were breast, lung, colorectal, oesophageal, gastric, pancreatic and soft tissue sarcoma. A Medline database search was carried out to identify those studies in which gender was investigated as a prognostic indicator. RESULTS: Results from large, mostly retrospective series show that for 5 of these 7 tumour groups, there is evidence for a female survival advantage. In particular, this survival advantage is usually more prominent in early stage disease. CONCLUSION: Melanoma is not unique in showing a female survival advantage. Although the current literature does not address the mechanisms involved, we suggest that these are worth investigating as they may contribute to new treatment modalities aimed at preventing metastatic spread.

Oestrogenic steroids and melanoma cell interaction with adjacent skin cells influence invasion of melanoma cells in vitro.

The invasion of melanoma is complex and multi-staged and involves changes in both cell/extracellular matrix (ECM) and cell/cell interactions. Female steroids and alpha-MSH have also been reported to influence metastatic melanoma progression, but their mechanisms of action are unknown. Accordingly, our aim was to establish in vitro models to examine (a) the influence of sex steroids and alpha-melanocyte-stimulating hormone (alpha-MSH) on tumour invasion and the influence of (b) ECM proteins and (c) adjacent cells on melanoma invasion. In the first model, melanoma cell invasion through fibronectin over 20 hr under serum-free conditions was used to investigate the effects of 17beta-oestradiol and oestrone on the invasion of human melanoma cell lines, A375-SM and HBL. A375-SM, but not HBL cells, proved very susceptible to inhibition by female steroids. However, invasion of the HBL line was inhibited by alpha-MSH. Using the second model of reconstructed human skin based on de-epidermised acellular dermis, we found that the HBL cells on their own failed to invade into the dermis (irrespective of the presence or absence of the basement membrane). However, there was a significant synergistic interaction between keratinocytes, fibroblasts and HBL cells, such that a modest invasion of HBLs into the dermis was seen within 2 weeks when other skin cells were present. In contrast, A375-SM cells showed a significant ability to invade the dermis in the absence of other cells, with less invasion when other skin cells were present. In summary, these models have provided new information on the extent to which melanoma cell invasion is sensitive to oestrogenic steroids and to alpha-MSH and to interaction, not only with adjacent skin cells but also to the presence of basement membrane antigens.