Prostate cancer cells survive anti-androgen and mitochondrial metabolic inhibitors by modulating glycolysis and mitochondrial metabolic activities.

BACKGROUND: Most cancer cells are more glycolytic even under aerobic conditions compared with their normal counterparts. Recent evidence of tumor cell metabolism, however, shows that some tumors also increase mitochondrial oxidative phosphorylation (ox-phos) at some disease states during progression and/or development of drug resistance. Our data show that anti-androgen enzalutamide (ENZA) resistant prostate cancer (PCa) cells use more mitochondrial metabolism leading to higher ox-phos as compared to the ENZA-sensitive cells and can become vulnerable to mitochondrial metabolism targeted therapies. METHODS: Seahorse assay, mass spectrometry and high resolution fluorescence confocal microscopy coupled with image analysis has been used to compare mitochondrial metabolism in ENZA-treated and -untreated anti-androgen-sensitive LNCaP and -resistant C4-2, CWR22ν1, and PCa2b cells. Ex vivo fluorescence microscopy and image analysis has been standardized to monitor mitochondrial electron transport (ETS) activity that likely increases ox-phos in circulating tumor cells (CTCs) isolated fom patients undergoing AR-targeted therapies. RESULTS: Our data show that PCa cells that are resistant to anti-androgen ENZA switch from glycolysis to ox-phos leading to an increased ETS activity. ENZA pretreated cells are more vulnerable to ETS component complex I inhibitor IACS-010759 (IACS) and mitochondrial glutaminase inhibitor CB-839 that reduces glutamate supply to tricarboxylic acid cycle. CTCs isolated from 6 of 20 patient blood samples showed relatively higher ETS activity than the rest of the patients. All six patients have developed ENZA resistance within less than 6 months of the sample collection. CONCLUSION: The enhanced growth inhibitory effects of mitochondrial metabolic inhibitors IACS and CB-839 in ENZA pretreated PCa cells provides a rationale for designing a drug combination trial. Patients can be selected for such trials by monitoring the mitochondrial ETS activities in their CTCs to maximize success.

Assessment of adherence and relative dose intensity with oral chemotherapy in oncology clinical trials at an academic medical center.

Background/Aims Oral chemotherapy is increasingly utilized leaving the patient responsible for self-administering an often complex regimen where adverse effects are common. Non-adherence and reduced relative dose intensity are both associated with poorer outcomes in the community setting but are rarely reported in clinical trials. The purpose of this study is to quantify adherence and relative dose intensity in oncology clinical trials and to determine patient and study related factors that influence adherence and relative dose intensity. Methods Patients were identified from non-industry-funded clinical trials conducted between 1 January 2009 and 31 March 2013 at the University of Wisconsin Carbone Cancer Center. Data were extracted from primary research records. Descriptive statistics and linear regression modeling was performed using SAS 9.4. Results A total of 17 clinical trials and 266 subjects were included. Mean adherence was greater than 97% for the first eight cycles. Mean relative dose intensity was less than 90% for the first cycle and declined over time. Male gender, a performance status of 1 or 2, metastatic disease, and traveling more than 90 miles to reach the cancer center were associated with higher relative dose intensity. Conclusions Patients with cancer enrolled in clinical trials are highly adherent but unlikely to achieve protocol specified relative dose intensity. Given that determining the phase II dose is the primary endpoint of phase I trials, incorporating relative dose intensity into this determination should be considered.

Leinamycin E1 acting as an anticancer prodrug activated by reactive oxygen species.

Leinamycin (LNM) is a potent antitumor antibiotic produced by Streptomyces atroolivaceus S-140, featuring an unusual 1,3-dioxo-1,2-dithiolane moiety that is spiro-fused to a thiazole-containing 18-membered lactam ring. Upon reductive activation in the presence of cellular thiols, LNM exerts its antitumor activity by an episulfonium ion-mediated DNA alkylation. Previously, we have cloned the lnm gene cluster from S. atroolivaceus S-140 and characterized the biosynthetic machinery responsible for the 18-membered lactam backbone and the alkyl branch at C3 of LNM. We now report the isolation and characterization of leinamycin E1 (LNM E1) from S. atroolivacues SB3033, a ΔlnmE mutant strain of S. atroolivaceus S-140. Complementary to the reductive activation of LNM by cellular thiols, LNM E1 can be oxidatively activated by cellular reactive oxygen species (ROS) to generate a similar episulfonium ion intermediate, thereby alkylating DNA and leading to eventual cell death. The feasibility of exploiting LNM E1 as an anticancer prodrug activated by ROS was demonstrated in two prostate cancer cell lines, LNCaP and DU-145. Because many cancer cells are under higher cellular oxidative stress with increased levels of ROS than normal cells, these findings support the idea of exploiting ROS as a means to target cancer cells and highlight LNM E1 as a novel lead for the development of anticancer prodrugs activated by ROS. The structure of LNM E1 also reveals critical new insights into LNM biosynthesis, setting the stage to investigate sulfur incorporation, as well as the tailoring steps that convert the nascent hybrid peptide-polyketide biosynthetic intermediate into LNM.

Adjuvant sunitinib or sorafenib for high-risk, non-metastatic renal-cell carcinoma (ECOG-ACRIN E2805): a double-blind, placebo-controlled, randomised, phase 3 trial.

BACKGROUND: Renal-cell carcinoma is highly vascular, and proliferates primarily through dysregulation of the vascular endothelial growth factor (VEGF) pathway. We tested sunitinib and sorafenib, two oral anti-angiogenic agents that are effective in advanced renal-cell carcinoma, in patients with resected local disease at high risk for recurrence. METHODS: In this double-blind, placebo-controlled, randomised, phase 3 trial, we enrolled patients at 226 study centres in the USA and Canada. Eligible patients had pathological stage high-grade T1b or greater with completely resected non-metastatic renal-cell carcinoma and adequate cardiac, renal, and hepatic function. Patients were stratified by recurrence risk, histology, Eastern Cooperative Oncology Group (ECOG) performance status, and surgical approach, and computerised double-blind randomisation was done centrally with permuted blocks. Patients were randomly assigned (1:1:1) to receive 54 weeks of sunitinib 50 mg per day orally throughout the first 4 weeks of each 6 week cycle, sorafenib 400 mg twice per day orally throughout each cycle, or placebo. Placebo could be sunitinib placebo given continuously for 4 weeks of every 6 week cycle or sorafenib placebo given twice per day throughout the study. The primary objective was to compare disease-free survival between each experimental group and placebo in the intention-to-treat population. All treated patients with at least one follow-up assessment were included in the safety analysis. This trial is registered with ClinicalTrials.gov, number NCT00326898. FINDINGS: Between April 24, 2006, and Sept 1, 2010, 1943 patients from the National Clinical Trials Network were randomly assigned to sunitinib (n=647), sorafenib (n=649), or placebo (n=647). Following high rates of toxicity-related discontinuation after 1323 patients had enrolled (treatment discontinued by 193 [44%] of 438 patients on sunitinib, 199 [45%] of 441 patients on sorafenib), the starting dose of each drug was reduced and then individually titrated up to the original full doses. On Oct 16, 2014, because of low conditional power for the primary endpoint, the ECOG-ACRIN Data Safety Monitoring Committee recommended that blinded follow-up cease and the results be released. The primary analysis showed no significant differences in disease-free survival. Median disease-free survival was 5·8 years (IQR 1·6-8·2) for sunitinib (hazard ratio [HR] 1·02, 97·5% CI 0·85-1·23, p=0·8038), 6·1 years (IQR 1·7-not estimable [NE]) for sorafenib (HR 0·97, 97·5% CI 0·80-1·17, p=0·7184), and 6·6 years (IQR 1·5-NE) for placebo. The most common grade 3 or worse adverse events were hypertension (105 [17%] patients on sunitinib and 102 [16%] patients on sorafenib), hand-foot syndrome (94 [15%] patients on sunitinib and 208 [33%] patients on sorafenib), rash (15 [2%] patients on sunitinib and 95 [15%] patients on sorafenib), and fatigue 110 [18%] patients on sunitinib [corrected]. There were five deaths related to treatment or occurring within 30 days of the end of treatment; one patient receiving sorafenib died from infectious colitis while on treatment and four patients receiving sunitinib died, with one death due to each of neurological sequelae, sequelae of gastric perforation, pulmonary embolus, and disease progression. Revised dosing still resulted in high toxicity. INTERPRETATION: Adjuvant treatment with the VEGF receptor tyrosine kinase inhibitors sorafenib or sunitinib showed no survival benefit relative to placebo in a definitive phase 3 study. Furthermore, substantial treatment discontinuation occurred because of excessive toxicity, despite dose reductions. These results provide a strong rationale against the use of these drugs for high-risk kidney cancer in the adjuvant setting and suggest that the biology of cancer recurrence might be independent of angiogenesis. FUNDING: US National Cancer Institute and ECOG-ACRIN Cancer Research Group, Pfizer, and Bayer.

Intermittent versus continuous androgen deprivation in prostate cancer.

BACKGROUND: Castration resistance occurs in most patients with metastatic hormone-sensitive prostate cancer who are receiving androgen-deprivation therapy. Replacing androgens before progression of the disease is hypothesized to prolong androgen dependence. METHODS: Men with newly diagnosed, metastatic, hormone-sensitive prostate cancer, a performance status of 0 to 2, and a prostate-specific antigen (PSA) level of 5 ng per milliliter or higher received a luteinizing hormone-releasing hormone analogue and an antiandrogen agent for 7 months. We then randomly assigned patients in whom the PSA level fell to 4 ng per milliliter or lower to continuous or intermittent androgen deprivation, with patients stratified according to prior or no prior hormonal therapy, performance status, and extent of disease (minimal or extensive). The coprimary objectives were to assess whether intermittent therapy was noninferior to continuous therapy with respect to survival, with a one-sided test with an upper boundary of the hazard ratio of 1.20, and whether quality of life differed between the groups 3 months after randomization. RESULTS: A total of 3040 patients were enrolled, of whom 1535 were included in the analysis: 765 randomly assigned to continuous androgen deprivation and 770 assigned to intermittent androgen deprivation. The median follow-up period was 9.8 years. Median survival was 5.8 years in the continuous-therapy group and 5.1 years in the intermittent-therapy group (hazard ratio for death with intermittent therapy, 1.10; 90% confidence interval, 0.99 to 1.23). Intermittent therapy was associated with better erectile function and mental health (P<0.001 and P=0.003, respectively) at month 3 but not thereafter. There were no significant differences between the groups in the number of treatment-related high-grade adverse events. CONCLUSIONS: Our findings were statistically inconclusive. In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20% greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy. Intermittent therapy resulted in small improvements in quality of life. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00002651.).

A multicenter phase 1/2a dose-escalation study of the antioxidant moiety of vitamin E 2,2,5,7,8-pentamethyl-6-chromanol (APC-100) in men with advanced prostate cancer.

BACKGROUND: A phase 1/2a dose escalation study of APC-100 (2,2,5,7,8-Pentamethyl-6-chromanol) was conducted to determine maximum tolerated dose (MTD), recommended phase 2 dose, toxicities and efficacy in men with castrate-resistant prostate cancer (CRPC). METHODS: This open label phase 1/2a study utilizes a time-to-event reassessment method (TITE-CRM) design. Patients in cohorts of 3 were treated with escalating doses of APC-100 (900 mg-2400 mg) orally once daily continuously. Cycles were 28 days. RESULTS: Twenty patients with CRPC were enrolled in the dose escalation cohort. One possible DLT (elevated ALT) was seen at dose level 1. No other DLTs were seen and no dose reductions were required. Most frequent AEs included nausea (grade 1 in 6 patients) and elevated transaminases (grade 1-3 in 5 patients). After enrolment of 20 patients the MTD was not reached, however the maximal feasible dose was exceeded due to the number of capsules ingested. Five of the 20 patients had stable disease as their best response. The median progression free survival (PFS) for the cohort was 2.8 months (range 1-8). CONCLUSIONS: APC-100 is a novel agent with dual mechanism of action functioning both as potent antioxidant as well as antiandrogen. No detectable APC-100 was found in the plasma at dose level 5 (2100 mg) and it was felt that maximal feasibility was nearly reached. APC-100 is being reformulated as a tablet to allow further dose escalation. Once a recommended phase 2 dose is established, future studies in prostate cancer chemoprevention should be conducted.

A phase I study of selumetinib (AZD6244/ARRY-142866), a MEK1/2 inhibitor, in combination with cetuximab in refractory solid tumors and KRAS mutant colorectal cancer.

BACKGROUND: KRAS mutations are clinically important predictors of resistance to EGFR-directed therapies in colorectal cancer (CRC). Oncogenic activation of the RAS/RAF/MEK/ERK signaling cascade mediates proliferation independent of growth factor signaling. We hypothesized that targeting MEK with selumetinib could overcome resistance to cetuximab in KRAS mutant CRC. METHODS: A phase I study (NCT01287130) was undertaken to determine the tolerability, and pharmacokinetic profiles of the combination of selumetinib and cetuximab, with an expanded cohort in KRAS-mutant CRC. RESULTS: 15 patients were treated in the dose escalation cohort and 18 patients were treated in the expansion cohort. Two dose-limiting toxicities were observed. One grade 3 acneiform rash and one grade 4 hypomagnesemia occurred. The most common grade 1 and 2 adverse events included rash, nausea/vomiting, diarrhea, and fatigue. The maximum tolerated dose was established at selumetinib 75 mg p.o. BID and cetuximab 250 mg/m(2) weekly following a 400 mg/m(2) load. Best clinical response in the dose escalation group included 1 unconfirmed partial response in a patient with CRC and stable disease (SD) in 5 patients (1 squamous cell carcinoma of the tonsil, 1 non-small cell lung cancer, and 3 CRC), and in the KRAS-mutant CRC dose expansion cohort, of the 14 patients who were evaluable for response, 5 patients had SD and 9 patients had progressive disease. CONCLUSIONS: The combination of selumetinib and cetuximab is safe and well tolerated. Minimal anti-tumor activity was observed in KRAS-mutant refractory metastatic CRC. Further investigations might be warranted in other cancer subtypes.

Expression of spermidine/spermine N(1) -acetyl transferase (SSAT) in human prostate tissues is related to prostate cancer progression and metastasis.

INTRODUCTION: Prostate cancer (PCa) in many patients remains indolent for the rest of their lives, but in some patients, it progresses to lethal metastatic disease. Gleason score is the current clinical method for PCa prognosis. It cannot reliably identify aggressive PCa, when GS is ≤ 7. It is shown that oxidative stress plays a key role in PCa progression. We have shown that in cultured human PCa cells, an activation of spermidine/spermine N(1) -acetyl transferase (SSAT; EC 2.3.1.57) enzyme initiates a polyamine oxidation pathway and generates copious amounts of reactive oxygen species in polyamine-rich PCa cells. METHOD: We used RNA in situ hybridization and immunohistochemistry methods to detect SSAT mRNA and protein expression in two tissue microarrays (TMA) created from patient's prostate tissues. We analyzed 423 patient's prostate tissues in the two TMAs. RESULTS: Our data show that there is a significant increase in both SSAT mRNA and the enzyme protein in the PCa cells as compared to their benign counterpart. This increase is even more pronounced in metastatic PCa tissues as compared to the PCa localized in the prostate. In the prostatectomy tissues from early-stage patients, the SSAT protein level is also high in the tissues obtained from the patients who ultimately progress to advanced metastatic disease. DISCUSSION: Based on these results combined with published data from our and other laboratories, we propose an activation of an autocrine feed-forward loop of PCa cell proliferation in the absence of androgen as a possible mechanism of castrate-resistant prostate cancer growth.

A phase I study to determine the maximum tolerated dose and safety of oral LR-103 (1α,24(S)Dihydroxyvitamin D2) in patients with advanced cancer.

BACKGROUND: The objective of this study was to determine the maximum tolerated dose and safety of LR-103, a Vitamin D analogue, in patients with advanced cancer. METHODS: In Step A, patients received oral LR-103 once daily in 14-day cycles with intra-patient dose escalation per accelerated dose escalation design. Dose limiting toxicity for Step A was defined as ≥grade 2 hypercalcemia and/or >grade 2 other toxicities. Starting dose was 5 µg/day. Step B used a 3+3 design starting at Step A maximum tolerated dose with 28-day cycles. Dose limiting toxicity was defined as ≥grade 3 hypercalcemia or any grade 3 or 4 non-hematologic toxicity, except hypercalciuria. RESULTS: Twenty-one patients were enrolled; eight were treated in Step A. At dose level 3 (15 µg/day), two patients had dose limiting toxicity. One had grade 4 hyperuricemia. The other had grade 4 GGT plus grade 3 alkaline phosphatase, fatigue and urinary tract infection (UTI). Dose level 2 (10 µg/day) was the maximum tolerated dose for Step A and was starting dose for Step B. The dose was escalated to dose level 5 (30 µg/day) with a patient experiencing grade 3 dose limiting toxicity of hypercalcemia. The study was discontinued before reaching the maximum tolerated dose due to sponsor decision. Modest increases in serum osteocalcin and calcium and decrease in parathyroid hormone were noted. Best response was stable disease; four patients were on therapy for six months or longer. CONCLUSION: Step A dose limiting toxicities limited accelerated dose escalation. The maximum tolerated dose of LR-103 was not reached prior to study termination and this agent is no longer being developed.

Targeting androgen receptor and JunD interaction for prevention of prostate cancer progression.

BACKGROUND: Multiple studies show that reactive oxygen species (ROS) play a major role in prostate cancer (PCa) development and progression. Previously, we reported an induction of Spermidine/Spermine N(1) -Acetyl Transferase (SSAT) by androgen-activated androgen receptor (AR)-JunD protein complex that leads to over-production of ROS in PCa cells. In our current research, we identify small molecules that specifically block AR-JunD in this ROS-generating metabolic pathway. METHODS: A high throughput assay based on Gaussia Luciferase reconstitution was used to identify inhibitors of the AR-JunD interaction. Selected hits were further screened using a fluorescence polarization competitor assay to eliminate those that bind to the AR Ligand Binding Domain (LBD), in order to identify molecules that specifically target events downstream to androgen activation of AR. Eleven molecules were selected for studies on their efficacy against ROS generation and growth of cultured human PCa cells by DCFH dye-oxidation assay and DNA fluorescence assay, respectively. In situ Proximity Ligation Assay (PLA), SSAT promoter-luciferase reporter assay, and western blotting of apoptosis and cell cycle markers were used to study mechanism of action of the lead compound. RESULTS: Selected lead compound GWARJD10 with EC(50) 10 µM against ROS production was shown to block AR-JunD interaction in situ as well as block androgen-induced SSAT gene expression at IC(50) 5 µM. This compound had no effect on apoptosis markers, but reduced cyclin D1 protein level. CONCLUSIONS: Inhibitor of AR-JunD interaction, GWARJD10 shows promise for prevention of progression of PCa at an early stage of the disease by blocking growth and ROS production.

A Phase I study of intermittently dosed vorinostat in combination with bortezomib in patients with advanced solid tumors.

BACKGROUND: Accumulating evidence shows evidence of efficacy with the combination of vorinostat and bortezomib in solid tumors. We previously examined a once-daily continuous dosing schedule of vorinostat in combination with bortezomib which was well tolerated in cycles 1 and 2; however, there was concern regarding the tolerability through multiple cycles. This study was conducted to evaluate an intermittent dosing schedule of vorinostat with bortezomib. METHODS: Vorinostat was initially administered orally twice daily on days 1-14 with bortezomib IV on days 1, 4, 8, and 11 of a 21 day cycle. Two DLTs (elevated ALT and fatigue) were observed at dose level 1, thus the protocol was amended to administer vorinostat intermittently twice daily on days 1-4 and 8-11. RESULTS: 29 patients were enrolled; 13 men and 16 women. Common cancer types included sarcoma, pancreatic, colorectal, GIST, and breast. The most common Grade 3-4 toxicities at any dose level included thrombocytopenia, fatigue, increased ALT, elevated INR, and diarrhea. DLTs in the intermittent dosing scheduled included thrombocytopenia and fatigue. The Cmax and AUC for the intermittent dosing regimen were similar to those observed in the daily dosing. In this heavily pretreated population, stable disease was observed in patients with sarcoma, colorectal adenocarcinoma and GIST. CONCLUSIONS: The MTD was established at vorinostat 300 mg BID on days 1-4 and 8-11 and bortezomib 1.3 mg/m(2) IV on days 1, 4, 8, and 11 of a 21 day cycle. Tolerability was not improved with the intermittent dosing schedule of vorinostat when compared to continuous dosing.

A phase I study of AT-101 with cisplatin and etoposide in patients with advanced solid tumors with an expanded cohort in extensive-stage small cell lung cancer.

BACKGROUND: A phase I, dose-escalation study of AT-101 with cisplatin and etoposide was conducted to determine the maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D), safety and pharmacokinetics in patients with advanced solid tumors, with an expanded cohort in patients with extensive-stage small cell lung cancer (ES-SCLC) to assess preliminary activity. METHODS: In the dose escalation portion, increasing doses of AT-101 were administered orally BID on days 1-3 along with cisplatin on day 1 and etoposide on days 1-3 of a 21 day cycle. At the RP2D, an additional 7 patients with untreated ES-SCLC were enrolled. RESULTS: Twenty patients were enrolled in the dose-escalation cohort, and 7 patients with ES-SCLC were enrolled in the expanded cohort. The MTD/RP2D was established at AT-101 40 mg BID days 1-3 with cisplatin 60 mg/m2 and etoposide 120 mg/m2 on day 1 of a 21 day cycle with pegfilgrastim support. Two DLTs of neutropenic fever were seen at dose level 1. After the addition of pegfilgrastim, no additional DLTs were observed. Grade 3/4 treatment-related toxicities included: diarrhea, increased AST, neutropenia, hypophosphatemia, hyponatremia, myocardial infarction and pulmonary embolism. No apparent PK interactions were observed between the agents. Preliminary activity was observed with PRs in patients with ES-SCLC, high-grade neuroendocrine tumor, esophageal cancer and NSCLC. CONCLUSIONS: AT-101 with cisplatin and etoposide is well tolerated with growth factor support. Anti-tumor activity was observed in a variety of cancers including ES-SCLC, supporting further investigation with BH-3 mimetics in combination with standard chemotherapy for ES-SCLC.

Docetaxel and dasatinib or placebo in men with metastatic castration-resistant prostate cancer (READY): a randomised, double-blind phase 3 trial.

BACKGROUND: Src kinase-mediated interactions between prostate cancer cells and osteoclasts might promote bone metastasis. Dasatinib inhibits tyrosine kinases, including Src kinases. Data suggests that dasatinib kinase inhibition leads to antitumour activity, affects osteoclasts, and has synergy with docetaxel, a first-line chemotherapy for metastatic castration-resistant prostate cancer. We assessed whether dasatinib plus docetaxel in chemotherapy-naive men with metastatic castration-resistant prostate cancer led to greater efficacy than with docetaxel alone. METHODS: In this double-blind, randomised, placebo-controlled phase 3 study, we enrolled men of 18 years or older with chemotherapy-naive, metastatic, castration-resistant prostate cancer, and adequate organ function from 186 centres across 25 countries. Eligible patients were randomly assigned (1:1) via an interactive voice response system to receive docetaxel (75 mg/m(2) intravenously every 3 weeks, plus oral prednisone 5 mg twice daily), plus either dasatinib (100 mg orally once daily) or placebo until disease progression or unacceptable toxicity. Randomisation was stratified by Eastern Cooperative Oncology Group performance status (0-1 vs 2), bisphosphonate use (yes vs no), and urinary N-telopeptide (uNTx) value (<60 µmol/mol creatinine vs ≥60 µmol/mol creatinine). All patients, investigators, and personnel involved in study conduct and data analyses were blinded to treatment allocation. The primary endpoint was overall survival, analysed by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00744497. FINDINGS: Between Oct 30, 2008, and April 11, 2011, 1522 eligible patients were randomly assigned to treatment; 762 patients were assigned to dasatinib and 760 to placebo. At final analysis, median follow-up was 19·0 months (IQR 11·2-25·1) and 914 patients had died. Median overall survival was 21·5 months (95% CI 20·3-22·8) in the dasatinib group and 21·2 months (20·0-23·4) in the placebo group (stratified hazard ratio [HR] 0·99, 95·5% CI 0·87-1·13; p=0·90). The most common grade 3-4 adverse events included diarrhoea (58 [8%] patients in the dasatinib group vs 27 [4%] patients in the placebo group), fatigue (62 [8%] vs 42 [6%]), and asthenia (40 [5%] vs 23 [3%]); grade 3-4 pleural effusions were uncommon (ten [1%] vs three [<1%]). INTERPRETATION: The addition of dasatinib to docetaxel did not improve overall survival for chemotherapy-naive men with metastatic castration-resistant prostate cancer. This study does not support the combination of dasatinib and docetaxel in this population of patients. FUNDING: Bristol-Myers Squibb.

The poly(ADP-ribose) polymerase inhibitor niraparib (MK4827) in BRCA mutation carriers and patients with sporadic cancer: a phase 1 dose-escalation trial.

BACKGROUND: Poly(ADP-ribose) polymerase (PARP) is implicated in DNA repair and transcription regulation. Niraparib (MK4827) is an oral potent, selective PARP-1 and PARP-2 inhibitor that induces synthetic lethality in preclinical tumour models with loss of BRCA and PTEN function. We investigated the safety, tolerability, maximum tolerated dose, pharmacokinetic and pharmacodynamic profiles, and preliminary antitumour activity of niraparib. METHODS: In a phase 1 dose-escalation study, we enrolled patients with advanced solid tumours at one site in the UK and two sites in the USA. Eligible patients were aged at least 18 years; had a life expectancy of at least 12 weeks; had an Eastern Cooperative Oncology Group performance status of 2 or less; had assessable disease; were not suitable to receive any established treatments; had adequate organ function; and had discontinued any previous anticancer treatments at least 4 weeks previously. In part A, cohorts of three to six patients, enriched for BRCA1 and BRCA2 mutation carriers, received niraparib daily at ten escalating doses from 30 mg to 400 mg in a 21-day cycle to establish the maximum tolerated dose. Dose expansion at the maximum tolerated dose was pursued in 15 patients to confirm tolerability. In part B, we further investigated the maximum tolerated dose in patients with sporadic platinum-resistant high-grade serous ovarian cancer and sporadic prostate cancer. We obtained blood, circulating tumour cells, and optional paired tumour biopsies for pharmacokinetic and pharmacodynamic assessments. Toxic effects were assessed by common toxicity criteria and tumour responses ascribed by Response Evaluation Criteria in Solid Tumors (RECIST). Circulating tumour cells and archival tumour tissue in prostate patients were analysed for exploratory putative predictive biomarkers, such as loss of PTEN expression and ETS rearrangements. This trial is registered with ClinicalTrials.gov, NCT00749502. FINDINGS: Between Sept 15, 2008, and Jan 14, 2011, we enrolled 100 patients: 60 in part A and 40 in part B. 300 mg/day was established as the maximum tolerated dose. Dose-limiting toxic effects reported in the first cycle were grade 3 fatigue (one patient given 30 mg/day), grade 3 pneumonitis (one given 60 mg/day), and grade 4 thrombocytopenia (two given 400 mg/day). Common treatment-related toxic effects were anaemia (48 patients [48%]), nausea (42 [42%]), fatigue (42 [42%]), thrombocytopenia (35 [35%]), anorexia (26 [26%]), neutropenia (24 [24%]), constipation (23 [23%]), and vomiting (20 [20%]), and were predominantly grade 1 or 2. Pharmacokinetics were dose proportional and the mean terminal elimination half-life was 36·4 h (range 32·8-46·0). Pharmacodynamic analyses confirmed PARP inhibition exceeded 50% at doses greater than 80 mg/day and antitumour activity was documented beyond doses of 60 mg/day. Eight (40% [95% CI 19-64]) of 20 BRCA1 or BRCA2 mutation carriers with ovarian cancer had RECIST partial responses, as did two (50% [7-93]) of four mutation carriers with breast cancer. Antitumour activity was also reported in sporadic high-grade serous ovarian cancer, non-small-cell lung cancer, and prostate cancer. We recorded no correlation between loss of PTEN expression or ETS rearrangements and measures of antitumour activity in patients with prostate cancer. INTERPRETATION: A recommended phase 2 dose of 300 mg/day niraparib is well tolerated. Niraparib should be further assessed in inherited and sporadic cancers with homologous recombination DNA repair defects and to target PARP-mediated transcription in cancer. FUNDING: Merck Sharp and Dohme.

Mediator kinase inhibition reverses castration resistance of advanced prostate cancer.

Mediator kinases CDK19 and CDK8, pleiotropic regulators of transcriptional reprogramming, are differentially regulated by androgen signaling, but both kinases are upregulated in castration-resistant prostate cancer (CRPC). Genetic or pharmacological inhibition of CDK8 and CDK19 reverses the castration-resistant phenotype and restores the sensitivity of CRPC xenografts to androgen deprivation in vivo. Prolonged CDK8/19 inhibitor treatment combined with castration not only suppressed the growth of CRPC xenografts but also induced tumor regression and cures. Transcriptomic analysis revealed that Mediator kinase inhibition amplified and modulated the effects of castration on gene expression, disrupting CRPC adaptation to androgen deprivation. Mediator kinase inactivation in tumor cells also affected stromal gene expression, indicating that Mediator kinase activity in CRPC molded the tumor microenvironment. The combination of castration and Mediator kinase inhibition downregulated the MYC pathway, and Mediator kinase inhibition suppressed a MYC-driven CRPC tumor model even without castration. CDK8/19 inhibitors showed efficacy in patient-derived xenograft models of CRPC, and a gene signature of Mediator kinase activity correlated with tumor progression and overall survival in clinical samples of metastatic CRPC. These results indicate that Mediator kinases mediated androgen-independent in vivo growth of CRPC, supporting the development of CDK8/19 inhibitors for the treatment of this presently incurable disease.

Phase II open label, multi-center clinical trial of modulation of intermediate endpoint biomarkers by 1α-hydroxyvitamin D2 in patients with clinically localized prostate cancer and high grade pin.

BACKGROUND: Prostate cancer is the most common malignancy and second leading cause of cancer related deaths in American men supporting the study of prostate cancer chemoprevention. Major risk factors for this disease have been associated with low serum levels of vitamin D. Here, we evaluate the biologic activity of a less calcemic vitamin D analog 1α-hydroxyvitamin D2 [1α-OH-D2] (Bone Care International, Inc.) in patients with prostate cancer and high grade prostatic intraepithelial neoplasia (HG PIN). METHODS: Patients with clinically organ-confined prostate cancer and HG PIN were randomized to 1α-OH-D2 versus placebo for 28 days prior to radical prostatectomy. Intermediate endpoint biomarkers included serum vitamin D metabolites, TGFß 1/2, free/total PSA, IGF-1, IGFBP-3, bFGF, and VEGF. Tissue endpoints included histology, MIB-1 and TUNEL staining, microvessel density and factor VIII staining, androgen receptor and PSA, vitamin D receptor expression and nuclear morphometry. RESULTS: The 1α-OH-D2 vitamin D analog was well tolerated and could be safely administered with good compliance and no evidence of hypercalcemia over 28 days. While serum vitamin D metabolite levels only slightly increased, evidence of biologic activity was observed with significant reductions in serum PTH levels. TGF-ß2 was the only biomarker significantly altered by vitamin D supplementation. Whether reduced TGF-ß2 levels in our study is an early indicator of response to vitamin D remains unclear. CONCLUSIONS: While further investigation of vitamin D may be warranted based on preclinical studies, results of the present trial do not appear to justify evaluation of 1α-OH-D2 in larger clinical prostate cancer prevention studies.

A phase I study of vorinostat in combination with bortezomib in patients with advanced malignancies.

BACKGROUND: A phase I study to assess the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), pharmacokinetics (PK) and antitumor activity of vorinostat in combination with bortezomib in patients with advanced solid tumors. METHODS: Patients received vorinostat orally once daily on days 1-14 and bortezomib intravenously on days 1, 4, 8 and 11 of a 21-day cycle. Starting dose (level 1) was vorinostat (400 mg) and bortezomib (0.7 mg/m(2)). Bortezomib dosing was increased using a standard phase I dose-escalation schema. PKs were evaluated during cycle 1. RESULTS: Twenty-three patients received 57 cycles of treatment on four dose levels ranging from bortezomib 0.7 mg/m(2) to 1.5 mg/m(2). The MTD was established at vorinostat 400 mg daily and bortezomib 1.3 mg/m(2). DLTs consisted of grade 3 fatigue in three patients (1 mg/m(2),1.3 mg/m(2) and 1.5 mg/m(2)) and grade 3 hyponatremia in one patient (1.5 mg/m(2)). The most common grade 1/2 toxicities included nausea (60.9%), fatigue (34.8%), diaphoresis (34.8%), anorexia (30.4%) and constipation (26.1%). Objective partial responses were observed in one patient with NSCLC and in one patient with treatment-refractory soft tissue sarcoma. Bortezomib did not affect the PKs of vorinostat; however, the Cmax and AUC of the acid metabolite were significantly increased on day 2 compared with day 1. CONCLUSIONS: This combination was generally well-tolerated at doses that achieved clinical benefit. The MTD was established at vorinostat 400 mg daily × 14 days and bortezomib 1.3 mg/m(2) on days 1, 4, 8 and 11 of a 21-day cycle.

Predicting Response of Triple-Negative Breast Cancer to Neoadjuvant Chemotherapy Using a Deep Convolutional Neural Network-Based Artificial Intelligence Tool.

PURPOSE: Achieving a pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) is associated with improved patient outcomes in triple-negative breast cancer (TNBC). Currently, there are no validated predictive biomarkers for the response to NAC in TNBC. We developed and validated a deep convolutional neural network-based artificial intelligence (AI) model to predict the response of TNBC to NAC. MATERIALS AND METHODS: Whole-slide images (WSIs) of hematoxylin and eosin-stained core biopsies from 165 (pCR in 60 and non-pCR in 105) and 78 (pCR in 31 and non-pCR in 47) patients with TNBC were used to train and validate the model. The model extracts morphometric features from WSIs in an unsupervised manner, thereby generating clusters of morphologically similar patterns. Downstream ranking of clusters provided regions of interest and morphometric scores; a low score close to zero and a high score close to one represented a high or low probability of response to NAC. RESULTS: The predictive ability of AI score for the entire cohort of 78 patients with TNBC ascertained by receiver operating characteristic analysis demonstrated an area under the curve (AUC) of 0.75. The AUC for stages I, II, and III disease were 0.88, 0.73, and 0.74, respectively. Using a cutoff value of 0.35, the positive predictive value of the AI score for pCR was 73.7%, and the negative predictive value was 76.2% for non-pCR patients. CONCLUSION: To our knowledge, this study is the first to demonstrate the use of an AI tool on digitized hematoxylin and eosin-stained tissue images to predict the response to NAC in patients with TNBC with high accuracy. If validated in subsequent studies, these results may serve as an ancillary aid for individualized therapeutic decisions in patients with TNBC.

Overall Survival and Updated Results for Sunitinib Compared With Interferon Alfa in Patients With Metastatic Renal Cell Carcinoma.

PURPOSE: A randomized, phase III trial demonstrated superiority of sunitinib over interferon alfa (IFN-α) in progression-free survival (primary end point) as first-line treatment for metastatic renal cell carcinoma (RCC). Final survival analyses and updated results are reported. PATIENTS AND METHODS: Seven hundred fifty treatment-naïve patients with metastatic clear cell RCC were randomly assigned to sunitinib 50 mg orally once daily on a 4 weeks on, 2 weeks off dosing schedule or to IFN-α 9 MU subcutaneously thrice weekly. Overall survival was compared by two-sided log-rank and Wilcoxon tests. Progression-free survival, response, and safety end points were assessed with updated follow-up. RESULTS: Median overall survival was greater in the sunitinib group than in the IFN-α group (26.4 v 21.8 months, respectively; hazard ratio [HR] = 0.821; 95% CI, 0.673 to 1.001; P = .051) per the primary analysis of unstratified log-rank test (P = .013 per unstratified Wilcoxon test). By stratified log-rank test, the HR was 0.818 (95% CI, 0.669 to 0.999; P = .049). Within the IFN-α group, 33% of patients received sunitinib, and 32% received other vascular endothelial growth factor-signaling inhibitors after discontinuation from the trial. Median progression-free survival was 11 months for sunitinib compared with 5 months for IFN-α (P < .001). Objective response rate was 47% for sunitinib compared with 12% for IFN-α (P < .001). The most commonly reported sunitinib-related grade 3 adverse events included hypertension (12%), fatigue (11%), diarrhea (9%), and hand-foot syndrome (9%). CONCLUSION: Sunitinib demonstrates longer overall survival compared with IFN-α plus improvement in response and progression-free survival in the first-line treatment of patients with metastatic RCC. The overall survival highlights an improved prognosis in patients with RCC in the era of targeted therapy.

Phase I trial of tremelimumab in combination with short-term androgen deprivation in patients with PSA-recurrent prostate cancer.

CTLA-4 blockade has demonstrated antitumor efficacy in human clinical trials. The antitumor mechanism is presumably mediated in part by the expansion of tumor-specific T cells. Androgen deprivation, the cornerstone of treatment for patients with metastatic prostate cancer, has been shown to elicit prostate tissue apoptosis and lymphocytic inflammation. We hypothesized that treatment with androgen deprivation, followed by an anti-CTLA-4 antibody, could augment a tumor-specific immune response elicited by androgen deprivation. We report here the results of a phase I trial evaluating a humanized monoclonal antibody targeting CTLA-4, CP-675,206 (tremelimumab), in combination with androgen deprivation using an antiandrogen. Eligible patients were those with PSA-recurrent prostate cancer after primary surgery and/or radiation therapy, not previously treated with androgen deprivation, and without radiographic evidence of metastatic disease. Subjects were treated in two cycles, 3 months apart, in which they received bicalutamide 150 mg daily days 1-28 and tremelimumab on day 29. The primary endpoint of the trial was safety. Secondary endpoints included measures of PSA kinetics and identification of a maximum tolerated dose. Eleven patients were enrolled and completed at least 1 year of follow-up. Dose-limiting toxicities included grade 3 diarrhea and skin rash. No favorable changes in PSA doubling time were observed in a period shortly after completing treatment; however, three patients experienced a prolongation in PSA doubling time detectable several months after completing treatment. The identification of delayed, prolonged favorable changes in serum PSA suggests that future studies could explore this combination in studies evaluating time to disease progression.