Przemyslaw Twardowski

Circulating Tumor Cell Counts Are Prognostic of Overall Survival in SWOG S0421: A Phase III Trial of Docetaxel With or Without Atrasentan for Metastatic Castration-Resistant Prostate Cancer

PURPOSE Circulating tumor cell (CTC) enumeration has not been prospectively validated in standard first-line docetaxel treatment for metastatic castration-resistant prostate cancer. We assessed the prognostic value of CTCs for overall survival (OS) and disease response in S0421, a phase III trial of docetaxel plus prednisone with or without atrasentan. PATIENTS AND METHODS CTCs were enumerated at baseline (day 0) and before cycle two (day 21) using CellSearch. Baseline counts and changes in counts from day 0 to 21 were evaluated for association with OS, prostate-specific antigen (PSA), and RECIST response using Cox regression as well as receiver operator characteristic (ROC) curves, integrated discrimination improvement (IDI) analysis, and regression trees. RESULTS Median day-0 CTC count was five cells per 7.5 mL, and CTCs < versus ≥ five per 7.5 mL were significantly associated with baseline PSA, bone pain, liver disease, hemoglobin, alkaline phosphatase, and subsequent PSA and RECIST response. Median OS was 26 months for < five versus 13 months for ≥ five CTCs per 7.5 mL at day 0 (hazard ratio [HR], 2.74 [adjusting for covariates]). ROC curves had higher areas under the curve for day-0 CTCs than for PSA, and IDI analysis showed that adding day-0 CTCs to baseline PSA and other covariates increased predictive accuracy for survival by 8% to 10%. Regression trees yielded new prognostic subgroups, and rising CTC count from day 0 to 21 was associated with shorter OS (HR, 2.55). CONCLUSION These data validate the prognostic utility of CTC enumeration in a large docetaxel-based prospective cohort. Baseline CTC counts were prognostic, and rising CTCs at 3 weeks heralded significantly worse OS, potentially serving as an early metric to help redirect and optimize therapy in this clinical setting.

Trastuzumab Plus Docetaxel in HER-2/neu-Positive Prostate Carcinoma Final Results from the California Cancer Consortium Screening and Phase II Trial

Overexpression of the HER‐2/neu oncoprotein has been reported to occur in ≤ 60% of patients with prostate carcinoma and to correlate with shortened survival. Trastuzumab is a humanized monoclonal antibody to the HER‐2 receptor and has activity against HER‐2–positive breast carcinoma, more so when combined with a taxane. The authors screened for HER‐2 overexpression in patients developing hormone‐refractory prostate carcinoma (HRPC) and conducted a Phase II trial of trastuzumab plus docetaxel in HER‐2–positive patients.

Docetaxel and atrasentan versus docetaxel and placebo for men with advanced castration-resistant prostate cancer (SWOG S0421): A randomised phase 3 trial

BACKGROUND The endothelin pathway has a role in bone metastases, which are characteristic of advanced prostate cancer. Atrasentan, an endothelin receptor antagonist, has shown activity in prostate cancer. We therefore assessed its effect on survival in patients with castration-resistant prostate cancer with bone metastases. METHODS In a double-blind phase 3 trial, men with metastatic castration-resistant prostate cancer, stratified for progression type (prostate-specific antigen or radiological), baseline pain, extraskeletal metastases, and bisphosphonate use, were randomly assigned in a 1:1 ratio to docetaxel (75 mg/m(2) every 21 days, intravenously) with atrasentan (10 mg/day, orally) or placebo for up to 12 cycles and treated until disease progression or unacceptable toxicity. Patients who did not progress on treatment were permitted to continue atrasentan or placebo for up to 52 weeks. Coprimary endpoints were progression-free survival (PFS) and overall survival. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00134056. FINDINGS 498 patients were randomly assigned to the atrasentan group and 496 to the placebo group. The trial was halted early for futility in April, 2011, after a planned interim analysis. Median PFS was 9·2 months (95% CI 8·5-9·9) in the atrasentan group and 9·1 months (8·4-10·2) in the placebo group (hazard ratio 1·02, 0·89-1·16; p=0·81). Median overall survival was 17·8 months (16·4-19·8) in the atrasentan group versus 17·6 months (16·4-20·1) in the placebo group (1·04, 0·90-1·19; p=0·64). 278 (57%) of 492 patients in the atrasentan group had grade 3 and greater toxicity compared with 294 (60%) of 486 in the placebo group (p=0·22). Three deaths in the atrasentan group and seven in the placebo group were judged to be possibly or probably due to protocol treatment. INTERPRETATION Atrasentan, when added to docetaxel, does not improve overall survival or PFS in men with castration-resistant prostate cancer and bone metastases; therefore, single-agent docetaxel should remain as one of the standard treatments. FUNDED National Cancer Institute, Sanofi-Aventis, and Abbott Laboratories.

Results of the Southwest Oncology Group phase II evaluation (study S0031) of ZD1839 for advanced transitional cell carcinoma of the urothelium.

Study Type – Prognosis (inception cohort)
 Level of Evidence 1b

The AKT inhibitor perifosine in biochemically recurrent prostate cancer: a phase II California/Pittsburgh cancer consortium trial.

BACKGROUND Perifosine is an oral alkylphospholipid that inhibits cancer cell growth through decreased Akt phosphorylation. We conducted a phase II trial of perifosine in patients with biochemically recurrent, hormone-sensitive prostate cancer. PATIENTS AND METHODS Eligible patients had histologically confirmed prostate cancer, previous prostatectomy and/or radiation therapy, and rising prostate-specific antigen (PSA) without radiographic evidence of metastasis. Previous androgen deprivation therapy < 9 months in duration (completed >or= 1 year before registration) was allowed. The primary endpoint was PSA response, defined as a decrease by >or= 50% from the pretreatment value. Treatment was composed of a loading dose of perifosine 900 mg orally on day 1, then 100 mg daily starting 24 hours later. RESULTS Of 25 patients, 24 were evaluable for response. After a median follow-up of 8 months, 5 patients (20%) had a reduction in serum PSA levels, but none met criteria for PSA response. Three patients immediately progressed with no response to therapy. Median progression-free survival was 6.64 months (range, 4.53-12.81 months). No change in the PSA doubling time (7 months) was observed before and after treatment initiation. Dose-limiting toxicities (all grade 3) included hyponatremia, arthritis, hyperuricemia, and photophobia. CONCLUSION Although well tolerated, perifosine did not meet prespecified PSA criteria for response as a single agent in biochemically recurrent prostate cancer. However, 20% of patients had evidence of PSA reduction, suggesting modest single-agent clinical activity. The role of perifosine in combination with androgen deprivation or chemotherapy is currently under investigation.

A phase II trial of the Src-kinase inhibitor AZD0530 in patients with advanced castration-resistant prostate cancer: A California Cancer Consortium study

Prostate cancer cells undergo neuroendocrine differentiation during androgen deprivation and secrete neuropeptides, hence activating androgen receptor-regulated genes. Src-family protein kinases are involved in neuropeptide-induced prostate cancer growth and migration. A phase II trial of AZD0530, an oral Src-family kinase inhibitor, in patients with advanced castration resistant prostate cancer was conducted. The primary endpoint was prostate cancer-specific antigen (PSA) response rate, defined as a 30% or greater decrease. A two-stage Simon design was used. Eligibility criteria included documentation of castration resistance (including antiandrogen withdrawal), adequate end-organ function, and performance status, and not more than one prior taxane-based chemotherapy regimen. AZD0530 was given at 175 mg orally once daily continuously. Rapid accrual led to 28 patients registering in the first stage. Median age was 67 years. Sixteen patients had performance status (PS) 0, eight patients had PS 1, and four patients had PS 2. Nine patients (32%) had prior docetaxel-based chemotherapy. Five patients had transient PSA reductions not meeting PSA response criteria. Median progression-free survival time was 8 weeks. Treatment was generally well tolerated. AZD0530, a potent oral Src kinase inhibitor, is feasible and tolerable in this pretreated patient population but possessed little clinical efficacy as monotherapy. Strong preclinical evidence warrants further investigation of AZD0530 in earlier-stage prostate cancer or as combination therapy.

Phase II Study of Aflibercept (VEGF-Trap) in Patients With Recurrent or Metastatic Urothelial Cancer, a California Cancer Consortium Trial

OBJECTIVES To determine whether aflibercept, a recombinant fusion protein that binds and neutralizes multiple vascular endothelial growth factor isoforms, is effective in the treatment of urothelial cancer. The efficacy of systemic therapies for advanced urothelial cancer after failure of front-line platinum-based chemotherapy is limited. Evidence has shown that vascular endothelial growth factor is important in the pathophysiology of urothelial cancer. METHODS Patients with measurable, metastatic, or locally advanced urothelial cancer previously treated with 1 platinum-containing regimen were enrolled. Aflibercept was administered at 4 mg/kg intravenously every 2 weeks. The response rate (RR) and progression-free survival (PFS) were assessed in a 2-stage accrual design (22 + 18). A maximum of 40 patients were to be accrued to rule out a null hypothesis RR of 4% and PFS of 3 months versus an alternative RR of 15% and PFS of 5.4 months, with α = 0.12 and β = 0.19. RESULTS A total of 22 patients were accrued. One partial response (4.5% RR, 95% confidence interval 0.1%-22.8%) was seen. The median PFS was 2.79 months (95% confidence interval 1.74-3.88). Attributable Grade 3 toxicities included fatigue, hypertension, proteinuria, pulmonary hemorrhage, pain, hyponatremia, anorexia, and lymphopenia. No treatment-related Grade 4 or greater toxicities occurred. CONCLUSIONS Aflibercept was well tolerated, with toxicity similar to those seen with other vascular endothelial growth factor pathway inhibitors; however, it had limited single-agent activity in patients with urothelial carcinoma previously treated with platinum-containing chemotherapy.

HER-2/neu is overexpressed infrequently in patients with prostate carcinoma: Results from the California Cancer Consortium Screening Trial

The overexpression of HER‐2/neu is found in 20–30% of patients with breast carcinoma and is an adverse prognostic factor. HER‐2 overexpression also has been reported in up to 60% of patients with hormone‐refractory prostate carcinoma (HRPC) and was correlated with shortened survival. Trastuzumab (Herceptin®) is a humanized monoclonal antibody that binds to the HER‐2 receptor and has antitumor activity in patients with HER‐2‐overexpressing breast carcinoma. The authors report the results of HER‐2 screening from a Phase II trial of chemotherapy with trastuzumab and docetaxel in patients with HER‐2‐overexpressing prostate carcinoma.

A Randomized Phase II Trial of the Matrix Metalloproteinase Inhibitor BMS-275291 in Hormone-Refractory Prostate Cancer Patients with Bone Metastases

Background: BMS-275291 is a selective matrix metalloproteinase inhibitor (MMPI) that does not inhibit sheddases implicated in the dose-limiting arthritis of older MMPIs. We conducted a randomized phase II trial of two doses of BMS-275291 (1,200 versus 2,400 mg) in hormone-refractory prostate cancer (HRPC) patients with bone metastases to probe for a dose-response relationship and to assess differential toxicities. Serial serum and urine specimens were collected to assess for markers of bone metabolism. Methods: The primary end point was 4-month progression-free survival (PFS). Eligibility criteria included documentation of androgen-independent disease (including anti-androgen withdrawal), skeletal metastasis, adequate end-organ function and performance status, and no more than one prior chemotherapy regimen. Patients were randomized to 1,200 mg orally once daily (arm A) or 1,200 mg orally twice daily (arm B). Response was assessed every 56 days. Results: Eighty patients were enrolled: 39 in arm A and 41 in arm B. There were no responders by prostate-specific antigen or measurable disease to treatment. Stable disease was noted at 8 weeks in 39% of patients in arm A and in 17% of patients in arm B. Progression of disease at 8 weeks was seen in 61% of patients in arm A versus 83% of patients in arm B. Median survival time was 21.6 months (95% confidence interval, 17.5; not reached), whereas median PFS time was 1.8 months (95% confidence interval 1.74; 2) for all patients. Patients in arm A had a median survival time that was not reached, whereas patients on arm B has a median survival time of 21 months (P = 0.2). PFS at 4 months favored arm A: 22% versus 10% (log-rank, P = 0.008). Grade 3 toxicities occurred in 5 (13%) patients in arm A and in 9 (22%) patients in arm B. Grade 4 toxicities were uncommon (only 4% of patients): one each of thrombosis, fatigue, and motor neuropathy was seen in the arm B. Bone marker studies showed that baseline serum levels of N-telopeptide, osteocalcin, procollagen I NH2-terminal propeptide, and PICP had prognostic significance for PFS and/or overall survival. Conclusions: Regardless of dose schedule, BMS-275291 was well tolerated in HRPC patients and had no dose-limiting arthritis. Toxicities differed modestly according to the dose schedule employed. As overall survival and PFS favored the once daily schedule, this dose schedule is recommended for future studies. Baseline markers of bone metabolism may have prognostic value in HRPC patients with bone metastases.

A Phase II Trial of Flavopiridol (NSC #649890) in Patients with Previously Untreated Metastatic Androgen-Independent Prostate Cancer

Purpose: Flavopiridol is a cyclin-dependent kinase inhibitor with preclinical activity against prostate cancer cell lines. A Phase II trial was conducted to determine the activity of flavopiridol in patients with metastatic hormone-refractory prostate cancer. Experimental Design: A total of 36 patients was enrolled from several institutions and treated with a 72-h continuous infusion of flavopiridol every 14 days at the eventual starting dose of 40 mg/m2/day. Dose escalation up to 60 mg/m2/day was permitted if no significant toxicity was observed. Responses were assessed every 12 weeks. Only those patients completing four courses of the 72-h infusion were considered evaluable for response because the primary objective was to determine progression-free survival at 6 months given the cytostatic nature of the agent. Results: This study was conducted in a two-stage fashion. During the first stage, at least 20 evaluable patients needed to be enrolled to assess response. There were 22 of 36 patients evaluable for response. No objective responses were observed. Only 4 patients had stable disease for 16, 26, 29, and 48 weeks, respectively, stopping the trial by design as only 3 of 22 (14%) of the patients met the 6-month progression-free survival end point. The most common toxicities were diarrhea (grade 1 and 2) and nausea, although some grade 3 and 4 diarrhea (11 and 6%, respectively) were evident. Conclusions: Flavopiridol has disappointing single-agent activity in hormone-refractory prostate cancer when administered at this dose and schedule. Its use in prostate cancer should be reserved for evaluation in combination therapies or alternative schedules.