Gavin M. Marx

Phase II study of thalidomide in the treatment of recurrent glioblastoma multiforme.

Treatment options and prognosis remains poor for patients with recurrent glioblastoma multiforme. These tumors are highly vascularised and over express angiogenic factors such as vascular endothelial growth factor and may potentially be responsive to antiangiogenic therapies. We present the results of a phase II trial of Thalidomide, an antiangiogenic agent, in the treatment of recurrent glioblastoma multiforme. Patients were treated with 100u2009mg/day of Thalidomide, increased at weekly intervals by 100u2009mg to a maximum tolerated dose of 500u2009mg/d.Forty-two patients were enrolled, with 38 patients being assessable for response and 39 for toxicity. Two patients (5%) achieved a partial response and 16 (42%) had stable disease. The median survival was 31 weeks and the 1-year survival was 35%. Patients who had a partial response or stable disease had either a stabilisation or improvement in quality of life scores or performance status. Overall Thalidomide was well tolerated with no grade 4 toxicities and no treatment related deaths. The median maximum tolerated dose was 300u2009mg/day. The most common toxicity was fatigue to which patients developed tachyphylaxis. There was no correlation demonstrated with plasma vascular endothelial growth factor levels and response or survival.Thalidomide is a well-tolerated drug that may have some activity in the treatment of recurrent glioblastoma. Optimum dosing with antiangiogenic agents is currently under investigation. Chronic low dose therapy may be required to see conventional responses or improvements in time to progression. The dose required to achieve optimal biological impact may be better defined once we have established reliable surrogate endpoints.

Denosumab and Bone Metastasis–Free Survival in Men With Nonmetastatic Castration-Resistant Prostate Cancer: Exploratory Analyses by Baseline Prostate-Specific Antigen Doubling Time

PURPOSEnDenosumab, an anti-RANK ligand monoclonal antibody, significantly increases bone metastasis-free survival (BMFS; hazard ratio [HR], 0.85; P = .028) and delays time to first bone metastasis in men with nonmetastatic castration-resistant prostate cancer (CRPC) and baseline prostate-specific antigen (PSA) ≥ 8.0 ng/mL and/or PSA doubling time (PSADT) ≤ 10.0 months. To identify men at greatest risk for bone metastasis or death, we evaluated relationships between PSA and PSADT with BMFS in the placebo group and the efficacy and safety of denosumab in men with PSADT ≤ 10, ≤ 6, and ≤ 4 months.nnnPATIENTS AND METHODSnA total of 1,432 men with nonmetastatic CRPC were randomly assigned 1:1 to monthly subcutaneous denosumab 120 mg or placebo. Enrollment began February 2006; primary analysis cutoff was July 2010, when approximately 660 men were anticipated to have developed bone metastases or died.nnnRESULTSnIn the placebo group, shorter BMFS was observed as PSADT decreased below 8 months. In analyses by shorter baseline PSADT, denosumab consistently increased BMFS by a median of 6.0, 7.2, and 7.5 months among men with PSADT ≤ 10 (HR, 0.84; P = .042), ≤ 6 (HR, 0.77; P = .006), and ≤ 4 months (HR, 0.71; P = .004), respectively. Denosumab also consistently increased time to bone metastasis by PSADT subset. No difference in survival was observed between treatment groups for the overall study population or PSADT subsets.nnnCONCLUSIONnPatients with shorter PSADT are at greater risk for bone metastasis or death. Denosumab consistently improves BMFS in men with shorter PSADT and seems to have the greatest treatment effects in men at high risk for progression.

Identification of candidate biomarkers of therapeutic response to docetaxel by proteomic profiling.

Docetaxel chemotherapy improves symptoms and survival in men with metastatic hormone-refractory prostate cancer (HRPC). However, approximately 50% of patients do not respond to Docetaxel and are exposed to significant toxicity without direct benefit. This study aimed to identify novel therapeutic targets and predictive biomarkers of Docetaxel resistance in HRPC. We used iTRAQ-mass spectrometry analysis to identify proteins associated with the development of Docetaxel resistance using Docetaxel-sensitive PC3 cells and Docetaxel-resistant PC3-Rx cells developed by Docetaxel dose escalation. Functional validation experiments were performed using recombinant protein treatment and siRNA knockdown experiments. Serum/plasma levels of the targets in patient samples were measured by ELISA. The IC(50) for Docetaxel in the PC3-Rx cells was 13-fold greater than the parent PC-3 cell line (P = 0.004). Protein profiling identified MIC-1 and AGR2 as respectively up-regulated and down-regulated in Docetaxel-resistant cells. PC-3 cells treated with recombinant MIC-1 also became resistant to Docetaxel (P = 0.03). Conversely, treating PC3-Rx cells with MIC-1 siRNA restored sensitivity to Docetaxel (P = 0.02). Knockdown of AGR2 expression in PC3 cells resulted in Docetaxel resistance (P = 0.007). Furthermore, increased serum/plasma levels of MIC-1 after cycle one of chemotherapy were associated with progression of the cancer (P = 0.006) and shorter survival after treatment (P = 0.002). These results suggest that both AGR2 and MIC-1 play a role in Docetaxel resistance in HRPC. In addition, an increase in serum/plasma MIC-1 level after cycle one of Docetaxel may be an indication to abandon further treatment. Further investigation of MIC-1 as a biomarker and therapeutic target for Docetaxel resistance in HRPC is warranted.

Circulating microRNAs are associated with docetaxel chemotherapy outcome in castration-resistant prostate cancer.

Background:Docetaxel is the first-line chemotherapy for castration-resistant prostate cancer (CRPC). However, response rates are ∼50% and determined quite late in the treatment schedule, thus non-responders are subjected to unnecessary toxicity. The potential of circulating microRNAs as early biomarkers of docetaxel response in CRPC patients was investigated in this study.Methods:Global microRNA profiling was performed on docetaxel-resistant and sensitive cell lines to identify candidate circulating microRNA biomarkers. Custom Taqman Array MicroRNA cards were used to measure the levels of 46 candidate microRNAs in plasma/serum samples, collected before and after docetaxel treatment, from 97 CRPC patients.Results:Fourteen microRNAs were associated with serum prostate-specific antigen (PSA) response or overall survival, according to Mann–Whitney U or log-rank tests. Non-responders to docetaxel and patients with shorter survival generally had high pre-docetaxel levels of miR-200 family members or decreased/unchanged post-docetaxel levels of miR-17 family members. Multivariate Cox regression with bootstrapping validation showed that pre-docetaxel miR-200b levels, post-docetaxel change in miR-20a levels, pre-docetaxel haemoglobin levels and visceral metastasis were independent predictors of overall survival when modelled together.Conclusions:Our study suggests that circulating microRNAs are potential early predictors of docetaxel chemotherapy outcome, and warrant further investigation in clinical trials.

Primary treatment of the prostate improves local palliation in men who ultimately develop castrate‐resistant prostate cancer

To determine whether local treatment of primary prostate cancer gives palliative benefit to men who later develop castrate‐resistant prostate cancer (CRPC). Local treatments of primary prostate cancer are defined as radical retropubic prostatectomy (RRP) or external beam radiation therapy (EBRT).

Pain and health-related quality of life in patients with advanced solid tumours and bone metastases: integrated results from three randomized, double-blind studies of denosumab and zoledronic acid.

PurposeThis analysis evaluated patient-reported outcomes and analgesic use in patients with bone metastases from solid tumours across three comparative studies of denosumab and zoledronic acid.MethodsPooled data were analysed from three identically designed double-blind phase III studies comparing subcutaneous denosumab 120xa0mg with intravenous zoledronic acid 4xa0mg monthly in patients with bone metastases from breast cancer (nu2009=u20092,046), castration-resistant prostate cancer (nu2009=u20091,901) or other solid tumours (nu2009=u20091,597). Pain severity, pain interference, health-related quality of life and analgesic use were quantified.ResultsAt baseline, approximately half of patients had no/mild pain (53xa0% [1,386/2,620] denosumab; 50xa0% [1,297/2,578] zoledronic acid). Denosumab delayed onset of moderate/severe pain by 1.8xa0months (median, 6.5 vs 4.7xa0months; hazard ratio, 0.83; 95xa0% CI, 0.76–0.92; pu2009<u20090.001; 17xa0% risk reduction) and clinically meaningful increases in overall pain interference by 2.6xa0months (median, 10.3 vs 7.7xa0months; hazard ratio, 0.83; 95xa0% CI, 0.75–0.92; pu2009<u20090.001; 17xa0% risk reduction) compared with zoledronic acid. Strong opioid use and worsening of health-related quality of life were less common with denosumab.ConclusionsAcross three large studies of patients with advanced solid tumours and bone metastases, denosumab prevented progression of pain severity and pain interference more effectively than zoledronic acid.

Influenza vaccination and chemotherapy: a shot in the dark?

Influenza infection is a potential cause of excess morbidity in patients who are immunosuppressed because of haemato-oncological malignancy or its treatment. Therefore vaccination against influenza is recommended in these patient groups. This systematic review of the literature and vaccine manafacturers data assesses the current levels of knowledge concerning influenza vaccination in this patient group. There is a paucity of data, and the patient groups in the studies are heterogeneous. Serological responses are generally lower than expected in healthy controls and may be critically dependent on the timing of vaccination relative to chemotherapy. Antibody levels considered protective in healthy individuals may not prevent clinical infection in those with malignant disease. There are no data on protection from clinical infection. The vaccine appears to be well tolerated in this patient group. It is reasonable to offer vaccination to patients receiving treatment for haemato-oncological disorders. However, the degree of clinical protection afforded may be inferior to that experienced by healthy individuals. Further trials are warranted to assess the magnitude of benefit and optimal schedules of vaccination.

Methylated Glutathione S-transferase 1 (mGSTP1) is a potential plasma free DNA epigenetic marker of prognosis and response to chemotherapy in castrate-resistant prostate cancer.

Background:Glutathione S-transferase 1 (GSTP1) inactivation is associated with CpG island promoter hypermethylation in the majority of prostate cancers (PCs). This study assessed whether the level of circulating methylated GSTP1 (mGSTP1) in plasma DNA is associated with chemotherapy response and overall survival (OS).Methods:Plasma samples were collected prospectively from a Phase I exploratory cohort of 75 men with castrate-resistant PC (CRPC) and a Phase II independent validation cohort (n=51). mGSTP1 levels in free DNA were measured using a sensitive methylation-specific PCR assay.Results:The Phase I cohort identified that detectable baseline mGSTP1 DNA was associated with poorer OS (HR, 4.2 95% CI 2.1–8.2; P<0.0001). A decrease in mGSTP1 DNA levels after cycle 1 was associated with a PSA response (P=0.008). In the Phase II cohort, baseline mGSTP1 DNA was a stronger predictor of OS than PSA change after 3 months (P=0.02). Undetectable plasma mGSTP1 after one cycle of chemotherapy was associated with PSA response (P=0.007).Conclusions:We identified plasma mGSTP1 DNA as a potential prognostic marker in men with CRPC as well as a potential surrogate therapeutic efficacy marker for chemotherapy and corroborated these findings in an independent Phase II cohort. Prospective Phase III assessment of mGSTP1 levels in plasma DNA is now warranted.

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

BACKGROUNDnDocetaxel (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.nnnPATIENTS AND METHODSnWe 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 weeksnnnRESULTSnTwenty-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%.nnnCONCLUSIONSnThe 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.

Risk of arterial thromboembolic events in patients with advanced colorectal cancer receiving bevacizumab

BACKGROUNDnBevacizumab is an antiangiogenic mAb with efficacy against several cancers, but it is associated with risk of arterial thromboembolism (ATE). Further data are needed to determine the safety of bevacizumab.nnnPATIENTS AND METHODSnWe recorded grade 3, 4, or 5 ATE events and other data (including age, baseline cardiovascular risk factors, history of ATE, and aspirin use) from 471 patients with metastatic colorectal cancer in the MAX (Mitomycin, Avastin, Xeloda) trial of capecitabine monotherapy versus capecitabine with bevacizumab with or without mitomycin C.nnnRESULTSnBevacizumab-treated patients had 12 grade 3, 4, or 5 ATEs (3.8% incidence). ATEs occurred in 2.1% of patients >65 years, 5% of those with a history of ATE, and 5% of those with cardiac risk factors. Age, history of ATE, or vascular risk factors did not increase risk. Aspirin users had a higher incidence than nonusers (8.9% versus 2.7%) but had higher rates of vascular risk factors.nnnCONCLUSIONSnBevacizumab was associated with a modestly higher risk of ATE, but safety was not significantly worse in older patients or patients with a history of ATE or vascular risk factors. The effect of aspirin in preventing ATE in patients receiving bevacizumab could not be determined from this study.