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.

Phase II multicenter, two-stage study of E7389 in patients with hormone refractory prostate cancer with advanced and/or metastatic disease stratified by prior chemotherapy

15513

Background: E7389 is a synthetic macrocyclic ketone derivative of the marine sponge product halichondrin B. A unique tubulin depolymerizer, E7389 induces nonproductive tubulin aggregates and inhibits tubulin polymerization. E7389 has demonstrated activity in refractory breast cancer and non small cell lung cancer with response rates of 14.7% and 9.7%, respectively. E7389 inhibits the growth of prostate cancer cell lines, including those (DU145) with over-expression of beta-tubulin III, which may confer resistance to taxanes. Methods: Phase II Simon two-stage study explores the activity and safety of E7389 as monotherapy without concomitant steroids in patients with histologically proven adenocarcinoma of the prostate that has progressed despite maintained castration. Patients are stratified into two groups that are analyzed separately, including those who failed either no prior chemotherapy (except mitoxanthrone or estramustine) or no more than one prior regimen with a tubulin binding agent, such as docetaxel. E7389 1.4 mg/m2 is administered as a 2 to 5 minute bolus IV infusion on Days 1 and 8 of 21-day cycles. PSA measurements are obtained at the end of each cycle. The primary objective is to assess PSA response using Bubley criteria. Results: Thus far, 57 patients (37 taxane pretreated and 20 taxane naïve) have been treated. The median age is 71 (range 48–91) with 43% of patients over 75. A total of 160 treatment cycles have been given (median: 2; range: 2–7). Twelve study drug related serious adverse events have been reported in 9 patients: PE (2), melena (2), fever, neutropenia, febrile neutropenia, UTI, anemia, DVT, chest pain, and renal failure (1). Based on preliminary data, the taxane-treated group has 2 PSA responses in the first 21 patients, and the taxane-naïve group has 4 PSA responses in the first 14 patients, allowing both groups to progress to Stage 2 with further accrual. Conclusions: In patients with hormone refractory prostate cancer, there is some evidence of single agent activity for E7389 in taxane naïve and taxane pretreated patients with acceptable toxicity. Preliminary results of activity allow further recruitment to proceed.

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Romidepsin (FK228), a histone deacetylase inhibitor: Final results of a phase II study in metastatic hormone refractory prostate cancer (HRPC)

15507

Background: Romidepsin is a bicyclic depsipeptide that inhibits histone deacetylase (HDAC). Translocations fusing TMPRSS2 gene and ERG oncogenic factor is associated with elevated HDAC-1 expression. HDAC inhibition results in accumulation of hyperacetylated histone proteins resulting in G1 and G2/M arrest, differentiation of transformed cells and apoptosis. Romidepsin can also inhibit HSP90, ablating androgen receptor expression. This is the 1st study to report activity of an HDAC inhibitor in HRPC. Methods: Romidepsin was administered intravenously at 13mg/m2 on days 1, 8 and 15 of a 28-day schedule. A 2-stage design was used. Eligibility criteria included: no prior chemotherapy, metastatic disease, QTcB <470msec, Karnofsky PS =80. The primary endpoint was to determine rate of disease control (complete response [CR], partial response [PR], stable disease [SD] for 6 months). Secondary endpoints were PSA response rate (RR), time to PSA and objective disease progression, safety profile, effect on disease related symptoms and pharmacokinetics (PK) of romidepsin. Results: Thirty-one patients were enrolled. Median age: 64 years (range 43–82). Twenty-one patients are evaluable for radiological and PSA response: 1 patient achieved a confirmed radiological PR lasting >6 months (m), and 2 confirmed SD for 6m. Four patients had SD lasting 5m (n=2) and 4m (n=2). The PSA RR was 7%. A 3rd patient had a 40% fall in PSA lasting 5m. The most common drug related adverse events were (all grades, %): nausea (84%), fatigue (77%), vomiting (65%), anorexia (61%), constipation (45%), dysguesia (35%), diarrhea (32%), thrombocytopaenia (32%), anemia (28%) and neutropenia (25%). There were no grade 4 events. Non-specific asymptomatic ST segment changes on ECG were seen in 15 % of patients; there was no evidence of significant QTc prolongation on ECG confirmed by manual calculation. Conclusions: Treatment with single agent romidepsin is associated with a disease control rate of 14% and a PSA RR of 7%. Constitutional toxicities are prominent, no grade 4 events have been observed and only minimal cardiac toxicity has been reported. Further investigation in combination with other active agents in HRPC is warranted.

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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 1, pharmacokinetic (PK) and pharmacodynamic (PD) study of CHIR-258, a novel oral multiple receptor tyrosine kinase (RTK) inhibitor

3043

Background: CHIR-258 is a potent small molecule inhibitor of VEGF, FGF, PDGF and c-KIT RTKs with IC50≤10nM that demonstrates activity in a variety of angiogenesis, tumour and metastasis models. Methods: Patients (pts) with histologically confirmed advanced solid tumors, ECOG PS 0–2 were treated in cohorts of 3–6 with CHIR-258. Treatment was as single daily doses on a repeated 7 days (d) on/7d off schedule (25–100mg), with a subsequent protocol amendment to continuous (cont) daily dosing. The objectives were to determine maximum tolerated dose (MTD) and dose limiting toxicity (DLT), evaluate PK and PD endpoints - ERK phosphorylation in PBL - and describe anti-tumour activity. Results: 35pts (median age 56.5 yrs; 15F/20M) were treated in 4 intermittent dosing cohorts (25, 50, 75, 100 mg/d) and 3 continuous dosing cohorts (100,125, 175 mg/d). The most common drug related adverse events were (grade [gr], number of pts): nausea (gr 1–3, 12); fatigue (gr 1–2, 9); headache (gr 1–3, 8); vomiting (gr 1–2, 7); anorexia (gr 1–2, 7); diarrhoea (gr 1–2, 6); dysgeusia (gr1–2, 6); anaemia (gr 2–3, 4); hypertension (gr 1–3, 3) and reversible asymptomatic drop in left ventricular ejection fraction (gr 2, 2). DLTs were gr 3 hypertension (HTN) in 1 pt with pre-existing HTN (100mg, cont); asymptomatic uncomplicated grade 2 elevation in cardiac troponin I (125mg); gr 3 anorexia/fatigue and gr 3 rise in alkaline phosphatase (both at 175mg). 3 pts have had prolonged stable disease (all 4m+; parotid, renal and imatinib-refractory GIST). The plasma PKs of CHIR-258 were linear over the dose range of 25–175 mg with respect to Cmax and AUC. On d1, the mean Cmax was 13.5(5.3) ng/mL to 109 (26) ng/mL, the mean AUC (0–24) was 224(97.4)ng*h/mL to 1740(466)ng*h/mL, and the t½ was 17h. Trough CHIR-258 concentrations at doses >50 mg/d were above the concentrations known to inhibit target receptor activation in vitro. Data on evaluable samples demonstrate up to 90% inhibition of basal ERK phosphorylation. Conclusions: CHIR-258 was safely administered at continuous daily doses up to 175mg/d. Modulation of p-ERK was demonstrated. Treatment is associated with disease stabilization.

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Phase I dose-escalation study of ZK 304709, an oral multi-target tumor growth inhibitor (MTGI), administered for 14 days of a 28-day cycle

2076

Background: ZK 304709 is a novel oral MTGI that induces cell cycle arrest and inhibits tumour angiogenesis by selectively inhibiting Cyclin Dependent Kinases (CDKs) 1, 2, 4, 7 and 9,VEGF-R 1, 2 and 3, and PDGF-Rβ tyrosine kinases. Methods: Adult patients (pts) (WHO PS ≤2) with a histologically or cytologically confirmed solid tumor, resistant or refractory to conventional therapy, were eligible. ZK304709 was administered orally, once daily, at a 15 mg starting dose, on days 1–14 of a 28-day cycle, then escalated by 33–100% depending on incidence of drug-related toxicity ≥ grade (gr) 2 (CTC v2.0). At least 3 pts were treated at each dose level. The primary objective was to identify the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT). Secondary objectives were to determine the tolerability, pharmacokinetic (PK) profile, and preliminary efficacy. Results: Interim results were available for 24 pts (19 M/5 F; median age 56.5) at 5 dose levels (15–120 mg qd). Pts received a median of 2 cycles (range 0–10). Common drug related toxicities were nausea, vomiting, and fatigue. Two DLT were observed: dizziness and hypertension. However, the MTD has yet to be established. The PK profile for dose levels up to 90 mg demonstrated rapid absorption and a dose-dependent increase of exposure and Cmax. Disease stabilization for ≥4 cycles has been observed. Conclusions: ZK 304709 was rapidly absorbed and has been tolerated on this schedule at up to 120 mg qd. The MTD has not been reached and enrolment is ongoing. These preliminary data demonstrate that oral delivery on this schedule of an agent that inhibits both cell cycle and angiogenesis is feasible.

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Phase I trial involving the pharmacodynamic (PD) study of circulating tumour cells, of CP-751,871 (C), a monoclonal antibody against the insulin-like growth factor 1 receptor (IGF-1R), with docetaxel (D) in patients (p) with advanced cancer

3023

Background: C is the first specific, fully human, monoclonal antibody to target IGF-1R in clinical trials. It potently inhibits IGF-1R signaling, enhancing D antitumour activity. This trial investigated the safety, feasibility, dose limiting toxicity (DLT), PK and antitumor activity of D administered with C every 3 weeks. PD studies evaluated circulating tumor cell (CTC) IGF-1R expression and CTC counts pre- and post-treatment. Methods: The C doses tested were 0.1, 0.4, 0.8, 1.5, 3.0, 6.0 and 10 mg/kg in sequential cohorts of 3–6 p. D was fixed at 75mg/m2. P achieving disease control continued on C alone if experiencing D toxicity. Results: 21 p (20 male) have received 100 courses of C with D. 7 p received 8 or more courses of the combination. A further 21 courses of C alone have been administered. No toxicity has been attributed to C to date with the observed toxicities being attributable to D. Grade 3/4 toxicities were neutropenia (16/21 p) and neutropenic fever in 2/21 p. Grade 3 diarrhea was reported in 3 p, but this was easily controlled with antidiarrheals. Transient grade 1 hyperglycaemia was noted largely on day 1, following steroid premedication (14 p), but no significant C related hyperglycemia has been observed. An MTD has not been reached. Serial echocardiograms demonstrated no cardiac toxicity. Of 18 castration resistant prostate cancer (CRPC) p treated, 4 have had a confirmed PR, with 2 unconfirmed PR and 2 having disease stabilization for > 6 months (median number of courses: 10; range: 3–12). 5 p have maintained SD with C alone for 2–7 courses. CTC were detected in 16 of 18 p (CTC numbers ranged from 1 to 202 in 7.5ml of blood). IGF-1R expression was detected in 12 p. CTC IGF-1R was undetectable following treatment with C at doses above 3 mg/kg. Conclusions: This combination is safe and feasible with no toxicity attributed to C and encouraging antitumor activity in CRPC.

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Phase II study of FK228 in patients with hormone refractory prostate cancer (HRPC)

14554

Background: FK228 is a bicyclic depsipeptide that inhibits histone deacetylase (HDAC). HDAC inhibition results in accumulation of hyperacetylated histone proteins resulting in G1 and G2/M arrest, differentiation of transformed cells and apoptosis. FK228 can also inhibit HSP90, ablating androgen receptor expression. Methods: FK228 was administered intravenously at 13mg/m2 on days 1, 8 and 15 of a 28-day schedule for up to 6 cycles. Sixteen patients were treated in stage 1. If ≥ 1 response was seen, an additional 9 patients were to be recruited. Eligibility criteria included: no prior chemotherapy, metastatic disease, ≤3 lines of hormonal therapy, QTcB <500 msec, Karnofsky PS ≥80. The primary endpoint was to measure rate of disease control (complete response [CR], partial response [PR], stable disease [SD] for 6 months). Secondary endpoints were PSA response rate, time to PSA and objective disease progression, safety profile, effect on disease related symptoms and pharmacokinetics (PK) of FK228. Results: Interim results are available after 16 patients were enrolled in stage 1 and 5 patients in stage 2. Median age (n = 21): 65 years (range 43–77). 3 patients have completed 6 cycles of treatment, 4 are ongoing and 14 have discontinued. 16 patients are evaluable for radiological response and 18 for PSA response: 1 has achieved a confirmed radiological PR (6 months [m]), and 6 have confirmed SD (2 for 6m, 1 for 5 m, 1 for 4 m+, 1 for 3 m+). 2 of 18 have had a 50% fall in PSA (6 m, 4 m+) and another a 40% fall (5m). Most common drug related adverse events are (grade [gr],%): fatigue (gr 1–2, 88%), nausea (gr 1–2, 77%; gr 3, 10%), anorexia (gr 1–2, 72%), vomiting (gr 1–2, 55%; gr 3, 10%), non-specific asymptomatic ECG changes (gr 1–3, 44%), diarrhoea (gr 1–2, 38%), thrombocytopaenia (gr 1–2, 33%) and weight loss (gr 1, 20%). Conclusions: Interim results of treatment with FK228 suggest clinically relevant antitumor activity with an 18% disease control rate and a 11% PSA response rate. Toxicity is manageable. Accrual into the study continues.

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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.