[Show abstract][Hide abstract] ABSTRACT: PURPOSEAs part of the ENTHUSE (Endothelin A Use) program, the efficacy and safety of zibotentan (ZD4054), an oral specific endothelin A receptor antagonist, has been investigated in combination with docetaxel in patients with metastatic castration-resistant prostate cancer (CRPC).Patients And methodsIn this randomized, double-blind, placebo-controlled, phase III study, patients received intravenous docetaxel 75 mg/m(2) on day 1 of 21-day cycles plus oral zibotentan 10 mg or placebo once daily. The primary end point was overall survival (OS). Secondary end points included time to pain and prostate-specific antigen (PSA) progression, pain and PSA response, progression-free survival, health-related quality of life, and safety.ResultsA total of 1,052 patients received study treatment (docetaxel-zibotentan, n = 524; docetaxel-placebo, n = 528). At the time of data cutoff, there had been 277 and 280 deaths, respectively. There was no difference in OS for patients receiving docetaxel-zibotentan compared with those receiving docetaxel-placebo (hazard ratio, 1.00; 95% CI, 0.84 to 1.18; P = .963). No significant differences were observed on secondary end points, including time to pain progression (median 9.3 v 10.0 months, respectively) or pain response (odds ratio, 0.84; 95% CI, 0.61 to 1.16; P = .283). The median time to death was 20.0 and 19.2 months for the zibotentan and placebo groups, respectively. The most commonly reported adverse events in zibotentan-treated patients were peripheral edema (52.7%), diarrhea (35.4%), alopecia (33.9%), and nausea (33.3%). CONCLUSION
Docetaxel plus zibotentan 10 mg/d did not result in a significant improvement in OS compared with docetaxel plus placebo in patients with metastatic CRPC.
[Show abstract][Hide abstract] ABSTRACT: Background:
Standard treatment options are limited for the management of non-metastatic castration-resistant prostate cancer (CRPC). This study, part of the ENTHUSE (EndoTHelin A USE) phase III programme, evaluated the efficacy and safety of the oral specific endothelin (ET)A receptor antagonist zibotentan vs placebo in patients with non-metastatic CRPC (non-mCRPC).
This was a multicentre, randomized, double-blind, phase III study. Patients (n=1421) with non-mCRPC and biochemical progression (determined by rising serum PSA levels) were randomized to receive zibotentan 10 mg or placebo once daily. Based on the lack of efficacy signal in another ENTHUSE phase III study, an interim analysis was performed to determine whether the study was likely to achieve the co-primary objectives of improved overall survival (OS) and progression-free survival (PFS).
Criteria for continuation of this study were not met. A total of 79 deaths and 293 progression events were recorded at final data cutoff. Zibotentan-treated patients did not significantly differ from placebo-treated patients for OS (hazard ratio (HR): 1.13; 95% confidence interval (CI): 0.73-1.76, P=0.589) or PFS (HR: 0.89; 95% CI: 0.71-1.12, P=0.330). The most commonly reported adverse events in zibotentan-treated patients were peripheral oedema (37.7%), headache (26.2%) and nasal congestion (24.9%); each occurred with >15% higher incidence than in the placebo group.
This trial was terminated early because of failure at interim analysis of the efficacy data to meet the defined criteria for continuation. Owing to the absence of demonstrable survival benefits in the ENTHUSE clinical studies, zibotentan is no longer under investigation as a potential treatment for prostate cancer.
Full-text · Article · Feb 2013 · Prostate cancer and prostatic diseases
[Show abstract][Hide abstract] ABSTRACT: Endothelin-1 and the endothelin A (ETA) receptor have been implicated in prostate cancer progression in bone. This study aimed to determine whether the specific ETA receptor antagonist, zibotentan, prolonged overall survival (OS) in patients with castration-resistant prostate cancer and bone metastases who were pain-free or mildly symptomatic for pain.
Patients were randomized 1:1 to zibotentan 10 mg/day or placebo, plus standard prostate cancer treatment. The primary endpoint was OS. Secondary endpoints included times to pain progression, chemotherapy use, new bone metastases, and safety. Efficacy endpoints were analyzed using a log-rank test.
A total of 594 patients were randomized (zibotentan, n = 299; placebo, n = 295). Median OS was 24.5 months in zibotentan-treated patients versus 22.5 months for placebo, but the difference did not reach statistical significance (hazard ratio, 0.87; 95.2% confidence interval, 0.69-1.10; P = .240). No statistically significant differences were observed for any secondary efficacy endpoints. Peripheral edema (44%) and headache (31%) were the most commonly reported adverse events in the zibotentan group. Cardiac failure events were higher in the zibotentan group than placebo (any grade, 5.7% and 1.7%; Common Terminology Criteria for Adverse Events grade ≥3, 3.0% and 1.0%, respectively); these were manageable and reversible.
In this large, randomized, placebo-controlled phase 3 trial, treatment with zibotentan 10 mg/day did not lead to a statistically significant improvement in OS in this patient population. Zibotentan had an acceptable safety profile. Cancer 2012.
[Show abstract][Hide abstract] ABSTRACT: This two-part study assessed the safety and tolerability of combined treatment with zibotentan (ZD4054), a specific endothelin A receptor antagonist, plus docetaxel in patients with metastatic castration-resistant prostate cancer.
Part A was an open-label, dose-finding phase to determine the safety and toxicity profile of zibotentan in combination with docetaxel. Patients received once-daily oral zibotentan 10 mg (initial cohort) or 15 mg in combination with docetaxel 75 mg/m(2) (administered on day 1 of each 21-day cycle) for up to 10 cycles. Part B was a double-blind phase which evaluated the safety and preliminary activity of zibotentan plus docetaxel. Patients were randomized 2:1 to receive zibotentan (at the highest tolerated dose identified in part A) plus docetaxel or placebo plus docetaxel.
Six patients were enrolled in part A (n = 3, zibotentan 10 mg; n = 3, zibotentan 15 mg). No dose-limiting toxicity was observed, thus zibotentan 15 mg in combination with docetaxel was evaluated in part B (n = 20, zibotentan plus docetaxel; n = 11, placebo plus docetaxel). CTCAE grade ≥3, most commonly neutropenia or leucopenia, were reported in 10 (50%) and nine (82%) patients in the zibotentan and placebo groups, respectively. One (17%) patient receiving placebo achieved complete response, two (22%) patients receiving zibotentan achieved partial response and stable disease occurred in six (67%) and three (50%) patients receiving zibotentan and placebo, respectively.
The tolerability of zibotentan plus docetaxel was consistent with the known profiles of each drug. Sufficient preliminary activity was seen with this combination to merit continued development.
[Show abstract][Hide abstract] ABSTRACT: Zibotentan (ZD4054) is a specific endothelin A (ETA) receptor antagonist being investigated for the treatment of prostate cancer. As zibotentan is eliminated by renal and metabolic routes, clearance may be reduced in patients with hepatic or renal impairment, leading to greater drug exposure.
Open-label studies investigated the PK and tolerability of zibotentan in subjects with hepatic or renal impairment, compared with those with normal organ function. In the hepatic and renal studies, respectively, subjects were divided into categories using Child-Pugh classification or 24-hour urine creatinine clearance (mild, moderate, or severe impairment and normal function). Each subject received a single oral dose of zibotentan 10 mg and PK sampling was undertaken. Within the hepatic study, AUC and Cmax were expressed as the ratio of geometric means and 90% CI for each impairment group compared with the normal function group. The possibility that hepatic impairment had a clinically relevant effect on exposure was considered if the upper 90% CI for the ratio exceeded 2. In the renal study, AUC, Cmax and t1/2 were analyzed using linear regression fitting effects for creatinine clearance and age.
In the hepatic and renal studies respectively, 32 subjects (eight per group) and 48 subjects received treatment (n = 18 normal, n = 12 mild, n = 9 moderate, n = 9 severe). Zibotentan Cmax was not significantly affected by hepatic or renal impairment. Compared with the normal function group, zibotentan AUC was 40% (1.40; 90% CI 0.91-2.17), 45% (1.45; 90% CI 0.94-2.24) and 190% (2.90; 90% CI 1.88-4.49) higher in subjects with mild, moderate and severe hepatic impairment, respectively, and 66% (1.66; 90% CI 1.38-1.99), 89% (1.89; 90% CI 1.50-2.39) and 117% (2.17; 90% CI 1.64-2.86) higher in subjects with mild, moderate and severe renal impairment, respectively. In both studies mean t1/2 increased and zibotentan clearance decreased with the degree of impairment. Headache was the most common AE in all groups.
Zibotentan absorption was unchanged, however, exposure was higher in subjects with hepatic or renal impairment due to slower clearance. This increased exposure did not result in differences in the range or severity of AEs observed.
ClinicalTrials.gov: NCT00672581 and AstraZeneca study number D4320C00016 (renal trial; conducted in Germany).
Full-text · Article · Mar 2011 · BMC Clinical Pharmacology
[Show abstract][Hide abstract] ABSTRACT: This study evaluated overall survival (OS) of patients with advanced non-squamous NSCLC following treatment with the specific endothelin A receptor antagonist, zibotentan in combination with pemetrexed compared with pemetrexed monotherapy.
In this double-blinded, placebo-controlled study, patients with advanced NSCLC with non-squamous histology who had failed first-line platinum-based chemotherapy were randomized to receive either once-daily zibotentan 10 mg in combination with 3-weekly pemetrexed 500 mg/m(2) or placebo plus 3-weekly pemetrexed 500 mg/m(2). OS was calculated as the interval from date of randomization to date of death from any cause. Safety and tolerability were evaluated by recording the incidence of adverse events (AE) according to Common Toxicity Criteria for AE (CTCAE).
Sixty-six patients were randomized and completed the study (zibotentan plus pemetrexed, n = 30; placebo plus pemetrexed, n = 36). At the data cutoff, a total of 44 deaths had occurred, 20 and 24 in the zibotentan and placebo groups, respectively. No significant difference in OS was observed between the zibotentan and placebo treatment groups (HR, 1.13; 80% CI 0.77, 1.67; P = 0.69). The majority of AE were of CTCAE grade 1 or 2, and the most commonly reported AE in both treatment groups was anemia (23 and 25% of patients in the zibotentan and placebo groups, respectively).
There was no survival signal in patients with NSCLC following treatment with zibotentan in combination with pemetrexed. No new issues related to safety for either zibotentan or pemetrexed were identified.
No preview · Article · Dec 2010 · Cancer Chemotherapy and Pharmacology
[Show abstract][Hide abstract] ABSTRACT: To report the final analysis of a Phase II trial, which investigated the safety and efficacy of the specific endothelin A receptor antagonist zibotentan (AstraZeneca, Macclesfield, UK) in patients with metastatic castration-resistant prostate cancer (CRPC).
Patients with CRPC and bone metastases who were pain free or mildly symptomatic for pain were randomized to receive once-daily oral tablets of zibotentan 10 mg, 15 mg or placebo. The primary endpoint was the time to progression and secondary endpoints included overall survival, change in the number of bone metastases, and safety.
In total, 312 patients were randomized (placebo, n= 107; zibotentan 10 mg, n= 107; zibotentan 15 mg, n= 98). The median duration of study treatment and median follow-up time were 4 and 22 months, respectively. At the final analysis, there were no statistical differences of the primary outcome of time to progression between treatment groups, although an improvement in overall survival was observed in the zibotentan groups compared to placebo. Consistent with the previous analyses for overall survival, hazard ratios (HRs) of less than one were sustained for both zibotentan 15 mg (HR, 0.76; 80% CI, 0.61-0.94; P= 0.103) and 10 mg (HR, 0.83; 80% CI, 0.67-1.02; P= 0.254). The most commonly reported adverse events considered to be related to zibotentan treatment were peripheral oedema, headache and nasal congestion.
The results obtained in the present study support endothelin A receptor antagonism as an approach for treating patients with CRPC. To confirm the survival signal observed in the present study, zibotentan is being investigated further in the ENdoTHelin A USE (ENTHUSE) Phase III clinical trial programme.
No preview · Article · Oct 2010 · BJU International
[Show abstract][Hide abstract] ABSTRACT: Zibotentan (ZD4054) is an oral, specific endothelin A receptor antagonist presently under investigation for the treatment of hormone-resistant prostate cancer. Preclinical in vitro studies suggest that zibotentan has the potential to act as a time-dependent inhibitor of the cytochrome P450 isozyme 3A4 (CYP3A4) metabolic pathway. In clinical practice, it is likely that zibotentan will be coadministered with drugs metabolized by this pathway; the potential exists, therefore, that zibotentan-induced drug interactions could occur.
The primary objective of this study was to evaluate the effect of zibotentan on the pharmaco-kinetics of a clinically relevant dose of midazolam in healthy volunteers. Secondary objectives were to evaluate exposure to zibotentan, ensure the safety of the healthy volunteers dosed, and investigate the effect of zibotentan on the pharmacokinetics of the midazolam metabolites 1-hydroxy midazolam and 4-hydroxy midazolam. The potency of zibotentan as a CYP3A4 inhibitor was also assessed.
This was an open-label, randomized, singlecenter, 2-period, Phase I, crossover study. Volunteers were randomized in a 1:1 ratio to 1 of 2 cohorts. In cohort 1, volunteers received a single dose of midazolam 7.5 mg on day 1 (treatment A) of a 2-day study period. After a minimum 7-day washout period, volunteers received zibotentan 10 mg once daily on days 1 through 7, plus a single dose of midazolam 7.5 mg on day 6 (treatment B) of a 7-day study period. In cohort 2, volunteers received treatment B followed by treatment A, with a minimum 7-day washout period between treatments. AUC(0-infinity) and C(max) data were expressed as geometric least squares mean ratios and 90% CIs for midazolam + zibotentan:midazolam. A moderate interaction between midazolam and zibotentan was predefined to have occurred if the upper 90% CI of the ratio was >1.5. Adverse events (AEs) were assessed according to the National Cancer Institute's Common Terminology Criteria for Adverse Events version 3. AE data were assessed based on information provided by the volunteer, through open-ended and nonleading verbal questions to the volunteer at each visit, and through observation by the investigational team, other care providers, or relatives.
Six volunteers (all white) were included in each cohort (cohort 1, mean [SD] age, 48  years; mean weight, 74  kg; cohort 2, mean age, 51  years; mean weight, 75  kg). Steady-state levels of zibotentan, achieved over 7 days, increased the midazolam AUC(0-infinity) by 1.2-fold compared with midazolam alone. The upper limits of the 90% CIs for the AUC(0-infinity) and C(max) ratios were below the predefined level of 1.5 (1.37 and 1.32, respectively). Zibotentan had no apparent effect on the pharmacokinetics of 1-hydroxy midazolam and 4-hydroxy midazolam. Fatigue was reported in 11 volunteers (92%) receiving midazolam monotherapy and 10 (83%) receiving midazolam combined with zibotentan. Headache was reported in all 12 volunteers after zibotentan monotherapy.
In this population of healthy male volunteers, once-daily zibotentan 10 mg increased the AUC(0-infinity) of midazolam 1.2-fold; however, the treatment ratio was below the predefined limit for clinical significance. Zibotentan was well tolerated when given alone or in combination with midazolam. The results indicate that once-daily zibotentan 10 mg acted as a weak inhibitor of the CYP3A4 pathway. ClinicalTrials. gov identifier: NCT00709553.
No preview · Article · Jul 2010 · Clinical Therapeutics
[Show abstract][Hide abstract] ABSTRACT: To assess the maximum well-tolerated dose (MWTD), dose limiting toxicity (DLT), pharmacokinetics (PK) and pharmacodynamics of zibotentan, a novel specific endothelin-A receptor antagonist, in patients with metastatic prostate cancer.
Patients with metastatic, castrate-resistant prostate cancer (CRPC) were treated with escalating doses of oral zibotentan (ZD4054) 10-200 mg once daily. The initial cohort received 28 daily doses (Period 1). Patients who had evidence of clinical benefit and who had not met any of the criteria for withdrawal were allowed to receive zibotentan at their current dose level until they no longer derived clinical benefit (Period 2). PK of zibotentan and changes in prostate-specific antigen and bone markers were also assessed.
Sixteen patients were evaluable for the safety and single-dose PK analyses. Eleven patients completed Period 1, and nine patients proceeded to Period 2. DLTs were encountered at 22.5 mg; one patient had grade 3 dyspnea and peripheral edema and a second patient had grade 3 headache and intraventricular hemorrhage. Enrollment was expanded at the 15 mg dose level to further determine the safety and tolerability of zibotentan. No DLTs were seen at 15 mg, and the most frequent adverse events were headache, peripheral edema, fatigue, nasal congestion and nausea.
The MWTD for zibotentan was 15 mg orally daily. The predominant adverse events observed were consistent with those reported for this class of drugs, and prolonged stable disease was noted in some patients. Phase III studies with zibotentan in men with metastatic CRPC are ongoing.
Full-text · Article · Sep 2009 · Investigational New Drugs
[Show abstract][Hide abstract] ABSTRACT: ZD4054 is an oral specific endothelin-A receptor antagonist in development for the treatment of hormone-resistant prostate cancer. Both renal and metabolic processes contribute to its overall clearance. Two preclinical in vitro studies investigated the metabolism of ZD4054 using human liver microsomes, individual cytochrome P450 (CYP) isozymes, and flavin-containing monooxygenase isoforms. Two Phase I open-label crossover volunteer studies subsequently investigated in vivo drug interactions between ZD4054 and the CYP450 inducer rifampicin or CYP3A4 inhibitor itraconazole. The most abundant metabolite produced in in vitro incubations accounted for 12.8% of radioactivity after ZD4054 was incubated with CYP3A4. No significant flavin-containing monooxygenase metabolism of ZD4054 was observed. In the in vivo studies, rifampicin co-administration reduced the area under the concentration-time curve and maximum plasma concentration of ZD4054 by 68% and 29%, respectively, whilst co-administration with itraconazole was associated with an increase in ZD4054 area under the curve of approximately 28%. While co-administration of CYP450 inducers might be associated with reduced efficacy of ZD4054, dose reduction is unlikely to be required with concomitant administration of CYP3A4 inhibitors.
[Show abstract][Hide abstract] ABSTRACT: The endothelin-A receptor (ETAR) has been implicated in the progression of prostate cancer.
To investigate the safety and efficacy of the specific ETAR antagonist ZD4054 in patients with metastatic hormone-resistant prostate cancer (HRPC).
Double-blind, placebo-controlled, randomised, parallel-group, multicentre, phase 2 trial in patients attending cancer centres with HRPC and bone metastases who were pain free or mildly symptomatic for pain.
Patients were randomised to receive once-daily oral tablets of ZD4054 10 mg, or ZD4054 15 mg, or placebo.
The primary end point was time to progression, defined as clinical progression, requirement for opiate analgesia, objective progression of soft-tissue metastases, or death in the absence of progression. Secondary end points included overall survival, time to prostate-specific antigen (PSA) progression, and safety. Statistical significance was preset at 20%.
A total of 312 patients were randomised (ZD4054 10 mg, n=107; ZD4054 15 mg, n=98; placebo, n=107). At the primary analysis, median time to progression was 3.6 mo, 4.0 mo, and 3.8 mo in the placebo, ZD4054 10 mg, and ZD4054 15 mg groups, respectively, with no statistically significant difference between ZD4054 groups and placebo (hazard ratio [HR] vs placebo for the ZD4054 10mg group: 0.88 [80% CI: 0.71-1.09]; HR vs placebo for the ZD4054 15 mg group: 0.83 [80% CI: 0.66-1.03]). However, a signal for prolonged overall survival was observed in the ZD4054 treatment groups versus placebo, based on 40 deaths. At a subsequent analysis after 118 deaths, this survival benefit was confirmed (HR vs placebo for the ZD4054 10 mg group, 0.55 [80% CI: 0.41-0.73], p=0.008; HR vs placebo for the ZD4054 15 mg group, 0.65 [80% CI: 0.49-0.86], p=0.052) but the differences in time to progression remained nonsignificant. Median overall survival was 17.3 mo, 24.5 mo, and 23.5 mo in the placebo group, the ZD4054 10 mg group, and the ZD4054 15 mg group, respectively. Discordance between results for time to progression and overall survival may be due to the sensitivity of the definition of progression. Adverse events were in line with the expected pharmacologic effects of an ETAR antagonist.
The primary end point of time to progression was not achieved in this study, but an improvement was seen in overall survival in both active treatment arms. ZD4054 was well tolerated.