Levoketoconazole, the 2S,4R Enantiomer of Ketoconazole, a New Steroidogenesis Inhibitor for Cushing's Syndrome Treatment.

INTRODUCTION: Racemic ketoconazole (RK) is a steroidogenesis inhibitor used for treatment of Cushing's syndrome. Levoketoconazole (COR-003), the pure 2S,4R enantiomer, is potentially more potent and safe compared to RK. We compared in vitro effects of levoketoconazole and RK on adrenocortical and pituitary adenoma cells. MATERIALS AND METHODS: HAC15 cells and 15 primary human neoplastic adrenocortical cultures (+/- ACTH), and murine (AtT20) and human corticotroph adenoma cultures were incubated with levoketoconazole or RK (0.01-10 µM). Cortisol and ACTH were measured using a chemiluminescence immunoassay system, and steroid profiles by liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: In HAC15, levoketoconazole inhibited cortisol at lower concentrations (IC50: 0.300 µM) compared to RK (0.611 µM; P < 0.0001). IC50 values of levoketoconazole for basal cortisol production in primary adrenocortical cultures varied over a 24-fold range (0.00578-0.140 µM), with 2 patients having a higher sensitivity for levoketoconazole vs RK (2.1- and 3.7-fold). LC-MS/MS analysis in selected cases revealed more potent inhibition of cortisol and other steroid profile components by levoketoconazole vs RK. In AtT20, levoketoconazole inhibited cell growth and ACTH secretion (10 µM: -54% and -38%, respectively), and levoketoconazole inhibited cell number in 1 of 2 primary human corticotroph pituitary adenoma cultures (-44%, P < 0.001). CONCLUSION: Levoketoconazole potently inhibits cortisol production in adrenocortical cells, with a variable degree of suppression between specimens. Levoketoconazole inhibits adrenal steroid production more potently compared to RK and might also inhibit ACTH secretion and growth of pituitary adenoma cells. Together with previously reported potential advantages, this indicates that levoketoconazole is a promising novel pharmacotherapy for Cushing's syndrome.

Abiraterone acetate plus prednisone in patients with newly diagnosed high-risk metastatic castration-sensitive prostate cancer (LATITUDE): final overall survival analysis of a randomised, double-blind, phase 3 trial.

BACKGROUND: In the interim analyses of the LATITUDE study, the addition of abiraterone acetate plus prednisone to androgen deprivation therapy (ADT) led to a significant improvement in overall survival and radiographic progression-free survival compared with placebos plus ADT in men with newly diagnosed high-risk metastatic castration-sensitive prostate cancer (mCSPC). Here, we present long-term survival outcomes and safety of abiraterone acetate plus prednisone and ADT from the final analysis of the LATITUDE study. METHODS: This is a multicentre, randomised, double-blind, phase 3 trial done at 235 sites in 34 countries. Eligible patients (men aged ≥18 years) had newly diagnosed, histologically or cytologically confirmed prostate cancer with metastases, Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, and at least two of the three high-risk prognostic factors (Gleason score of ≥8, presence of three or more lesions on bone scan, or presence of measurable visceral metastasis except lymph node metastasis). Patients were randomly assigned (1:1) to receive abiraterone acetate (1000 mg) once daily orally plus prednisone (5 mg) once daily orally and ADT (abiraterone acetate plus prednisone group) or matching placebos plus ADT (placebo group); each treatment cycle was 28 days. Randomisation was done by a centralised interactive web response system in a country-by-country scheme using permuted block randomisation, stratified by presence of visceral disease and ECOG performance status. The coprimary endpoint of overall survival was assessed in the intention-to-treat population. This study is registered at ClinicalTrials.gov, number NCT01715285 and is complete. FINDINGS: Between Feb 12, 2013, and Dec 11, 2014, 1209 patients were screened, of whom ten were ineligible because of study site violations. 1199 patients were randomly assigned to either the abiraterone acetate plus prednisone group (n=597) or placebo group (n=602). After the results of the first interim analysis (cutoff date Oct 31, 2016), the study was unmasked to patients and investigators, and patients in the placebo group were allowed to cross over to receive abiraterone acetate and prednisone plus ADT treatment as per a protocol amendment (Feb 15, 2017) in an open-label extension phase of the study (up to 18 months from the protocol amendment). This final analysis (data cutoff Aug 15, 2018) was done after a median follow-up of 51·8 months (IQR 47·2-57·0) and 618 deaths (275 [46%] of 597 in the abiraterone acetate plus prednisone group and 343 [57%] of 602 in the placebo group). Overall survival was significantly longer in the abiraterone acetate plus prednisone group (median 53·3 months [95% CI 48·2-not reached]) than in the placebo group (36·5 months [33·5-40·0]), with a hazard ratio of 0·66 (95% CI 0·56-0·78; p<0·0001). The most common grade 3-4 adverse events were hypertension (125 [21%] in the abiraterone acetate plus prednisone group vs 60 [10%] in the placebo group vs three [4%] in the 72 patients who crossed over from placebo to abiraterone acetate plus prednisone) and hypokalaemia (70 [12%] vs ten [2%] vs two [3%]). Serious adverse events of any grade occurred in 192 (32%) of 597 patients in the abiraterone acetate plus prednisone group, 151 (25%) of 602 in the placebo group, and four (6%) of 72 in the crossover group. The most common treatment-related serious adverse event was hypokalaemia (four [1%] patients in the abiraterone acetate plus prednisone group and none in the other groups). Treatment-related deaths occurred in three (<1%) patients each in the abiraterone acetate plus prednisone group (gastric ulcer perforation, sudden death, and cerebrovascular accident) and the placebo group (sudden death, cerebrovascular accident, and pneumonia), with none in the crossover group. INTERPRETATION: The combination of abiraterone acetate plus prednisone with ADT was associated with significantly longer overall survival than placebos plus ADT in men with newly diagnosed high-risk mCSPC and had a manageable safety profile. These findings support the use of abiraterone acetate plus prednisone as a standard of care in patients with high-risk mCSPC. FUNDING: Janssen Research & Development.

Pharmacokinetics and bioequivalence of generic and branded abiraterone acetate tablet: a single-dose, open-label, and replicate designed study in healthy Chinese male volunteers.

PURPOSE: Abiraterone acetate is a highly variable drug and has been approved for the treatment of patients with metastatic castration-resistant prostate cancer in many countries. This study was conducted to compare the pharmacokinetic profile between the test product (abiraterone acetate tablet) and reference product ZYTIGA® (250 mg) mainly. METHODS: To overcome the high intra-subject variability of abiraterone, a two-sequence and four-period crossover study was designed to assess bioequivalence between the two products in 32 healthy male Chinese subjects under fasting conditions. The plasma concentration of abiraterone was analyzed by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) assay and the reference-scaled procedure was used to determine bioequivalence for the pharmacokinetics parameters. RESULTS: The point estimate of geometric mean ratios with 90% confidence interval (CI) of maximum observed concentration (Cmax) and the area under the concentration-time curve (AUC0t) for abiraterone in the test and reference products were 100.19% (90% CI 87.05-115.32%) and 105.99% (90% CI 96.34-116.62%), respectively, and were both within the range of 80.00-125.00%. The 95% confidence upper limit bound for [Formula: see text] was - 0.1079 for Cmax and was - 0.0515 for AUC0t. CONCLUSIONS: Bioequivalence was demonstrated between the two abiraterone acetate products. The study also confirmed high intra-subject variability, for abiraterone: coefficient of variation (CV, %) of Cmax values for the test and reference products were 40.33% and 46.58%, while for AUC0t were 24.02% and 34.16%, respectively. TRIAL REGISTRATION: http://www.chinadrugtrials.org.cn/ : CTR20170997.

Abiraterone acetate plus LHRH therapy versus abiraterone acetate while sparing LHRH therapy in patients with progressive, metastatic and chemotherapy-naïve, castration-resistant prostate cancer (SPARE): study protocol for a randomized controlled trial.

BACKGROUND: The value of continuation of luteinizing hormone-releasing hormone (LHRH) therapy in castration-resistant prostate cancer (CRPC) remains controversial and clear evidence is lacking. Argumentation for cessation of LHRH therapy is the prolonged suppression of testosterone levels after the withdrawal of LHRH analogues and the fact that disease progression occurs despite castration levels of testosterone. Especially upon treatment with the life-prolonging cytochrome P450 17-alpha-hydroxylase (Cyp17)-inhibitor, abiraterone, which has the ability to further suppress testosterone serum levels over LHRH therapy alone, continuation of LHRH therapy seems to be negligible. However, the proven increase of luteinizing hormone levels after LHRH withdrawal, which is even further increased by abiraterone, may counteract the effects of abiraterone by the induction of enzymes of steroidogenesis. Therefore, cessation of LHRH therapy when starting treatment with abiraterone in CRPC may display an unpredictable hazard to the patients. This study will explore the role of continuation of LHRH therapy when starting treatment with abiraterone in patients with asymptomatic or mildly symptomatic, chemotherapy-naïve CPRC. METHODS/DESIGN: The trial will assess radiographic progression-free survival after 12 months of treatment with abiraterone/prednisone in patients who will be randomized to receive continuing LHRH therapy versus LHRH withdrawal at the time of starting abiraterone therapy. DISCUSSION: This multicenter, prospective, randomized, exploratory phase-II trial will bring about new data regarding the efficacy and safety of abiraterone/prednisone treatment with or without continuation of LHRH therapy. In addition, further insight into the complex hormonal changes under treatment will be gained and the results of this trial may give rise to a larger phase-III trial to examine the possibility of withdrawing LHRH therapy in patients with CRPC. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02077634 . Registered on 9 December 2013.

Sequential use of the androgen synthesis inhibitors ketoconazole and abiraterone acetate in castration-resistant prostate cancer and the predictive value of circulating androgens.

PURPOSE: Patients previously treated with ketoconazole were excluded from phase III trials of abiraterone acetate due to potential overlapping mechanism of action. The purpose of this study was to determine the clinical utility of abiraterone and its impact on circulating androgens following ketoconazole. EXPERIMENTAL DESIGN: Chemotherapy-naïve patients with progressive metastatic castration-resistant prostate cancer (mCRPC) and prior ketoconazole therapy ≥28 days received abiraterone acetate 1,000 mg daily and prednisone 5 mg twice daily. The primary endpoint was the proportion of patients with PSA response, defined as ≥30% PSA decline at 12 weeks. H0 = 0.30 versus H1 = 0.50 (α = 0.05, power = 0.83). Circulating androgen levels were measured using liquid chromatography tandem mass spectrometry. RESULTS: Thirty-nine patients were included in the final analysis. Twenty (51%; 95% confidence interval, 36%-66%) patients had ≥30% PSA decline; the null hypothesis was rejected. Sixteen (41%) had ≥50% PSA decline. Median PFS (progression-free survival) was 16 weeks; median radiographic PFS (rPFS) was 36 weeks. Samples for measurement of baseline androgens were available in 37 patients. The PSA response proportion was 59% in 29 patients with DHEA ≥ limit of quantitation (LOQ), compared with 13% in 8 patients with DHEA < LOQ (P = 0.042). Median PFS was 6 and 16 weeks in DHEA < LOQ and DHEA ≥ LOQ patients, respectively (P = 0.017); median rPFS was 14 and 36 weeks in DHEA < LOQ and DHEA ≥ LOQ patients, respectively (P < 0.001). CONCLUSIONS: Abiraterone demonstrates modest clinical efficacy in mCRPC patients previously treated with ketoconazole. Patients with DHEA ≥ LOQ were more likely to demonstrate PSA responses and longer PFS. Analysis of circulating androgens merits further investigation as a biomarker for response to androgen synthesis inhibitor therapy.