The study was initiated in March of 2007 and completed accrual in July, 2010. Fifty-two subjects were consented with two ultimately found to not meet inclusion criteria. Fifty subjects were randomized with 25 receiving Polyphenon E and 25 receiving placebo. One subject in each group subsequently cancelled their planned surgery, leaving 24 subjects in each group who completed intervention. A Consort flow diagram of the study is shown in .
The two groups were well matched for demographics with age, race, and body mass index being similar between those who received Polyphenon E and placebo. Mean age was 63.4 years versus 61.3 years respectively (p=0.25). The majority of subjects in both groups were White (96% versus 92% respectively) with 1 multiracial subject in the Polyphenon E group and 1 Native American and 1 multiracial subject in the placebo group. The mean body mass index was 26.9 and 28.1 in each group respectively (p=0.25). The time period between original diagnosis and start of intervention varied among study subjects (from 21 days to a year).
Clinical characteristics of pre-study PSA and biopsy Gleason score were similar between the groups. The mean PSA in the Polyphenon E group was 6.71 with a standard deviation of 4.04 versus 7.90 with a standard deviation of 5.54 in the placebo group (p=0.38). Most subjects in both groups had biopsy Gleason scores of 3+3=6 (70.8% versus 70.8%) while 16.7% and 20.8% had Gleason's score 7 disease on biopsy, respectively (p=1.00). Details of the demographic and clinical characteristics in each group are shown in .
Clinical characteristics of the study subjects who completed the intervention
Polyphenon E was well tolerated with minimal adverse events and no withdrawals from the study secondary to adverse events. A total of 18 and 39 adverse events occurred in the Polyphenon E and placebo groups, respectively. summarizes the adverse events occurring in greater than 4 percent of subjects treated with Polyphenon E or placebo (more than 1 subject experiencing the event in either group). Nausea was the most common event, with a similar incidence rate in each group (16% vs. 16%). Other common AEs in the Polyphenon E group include diarrhea (8% vs. 20% for Polyphenon E vs. placebo), and headache (4% vs. 8% for Polyphenon E vs. placebo). These were all Grade 1 or Grade 2 events based on the NCI Common Terminology Criteria for Adverse Events (CTCAE) version 3.0. One subject in the Polyphenon E group had a mild ALT elevation (4%) while no ALT elevation was noted in the placebo group (data not shown). One subject in the placebo group had a grade 4 neutropenia in the end-of-study lab, however, this was most likely a lab error because the pre-op (3 days before the end- of-study lab) and post-op (3 days after the end-of-study lab) lab values were within normal range (data not shown).
Summary of adverse events occurring in greater than 4 percent of subjects treated with Polyphenon E or placebo, regardless of attribution.
Post-intervention plasma green tea polyphenol concentrations following 3–6 weeks of Polyphenon E intervention are shown in . EGCG, the main component catechin in Polyphenon E, reached average plasma levels of 146.6 pmol/ml in subjects given Polyphenon E while lower levels were achieved for the other catechins. The large inter-individual variation in plasma concentrations of tea polyphenols is mostly attributed to the difference in timing of blood collection in relation to the intake of the Polyphenon E. Eighteen of the twenty-hour subjects receiving Polyphenon E had measurable plasma green tea polyphenol concentrations. Five of six Polyphenon E subjects who had no detectable post-intervention plasma green tea polyphenol concentrations had their post-intervention samples collected more than 16 hours after the previous Polyphenon E dose. None of the subjects receiving placebo had detectable plasma green tea polyphenol concentrations.
Figure 2 Post-intervention plasma green tea polyphenol concentrations following 3–6 weeks of Polyphenon E intervention. EGC: epigallocatechin; EC: epicatechin; ECG: epicatechin gallate; EGCG: epigallocatechin gallate; 4″-MeEGCG: 4″-O-methyl (more ...)
Fresh frozen tissue was available from 15 subjects receiving Polyphenon E and from 19 subjects receiving placebo for green tea polyphenol analysis. Two of the placebo subjects had detectable epicatechin gallate (ECG) peak in the prostate tissue, suggesting that the ECG peak identified in our system for the prostate tissue may not be specific to ECG. Alternatively, the ECG peak detected could be derived from other sources of intake. No other green tea polyphenols were detected in the placebo group. Five of the 15 Polyphenon E subjects had detectable ECG peak, ranging from 17.77 to 59.67 pmol/g. One of the 15 Polyphenon E subjects had detectable concentrations of each of the green tea polyphenols analyzed; epigallocatechin (EGC) 88.71 pmol/g, epicatechin (EC) 226.74 pmol/g, ECG 37.35 pmol/g, EGCG 36.05 pmol/g, and 4″-O-methyl-EGCG (4″-MeEGCG) 12.33 pmol/g. One subject had detectable tissue EC concentrations (83.06 pmol/g).
Systemic biomarker endpoints are summarized in . Note that PSA values collected pre-intervention were lower than those at diagnosis because of variations between values obtained from ELISA testing in our lab for pre-intervention testing and clinical lab results used for PSA values at diagnosis. PSA values demonstrated a greater decrease for those on Polyphenon E than those on placebo but this did not reach statistical significance (−0.66 ±2.56 and −0.08 ±1.28, ng/ml, p=0.26). When comparing the proportion of those who had a decrease in PSA to those that did not, 58.3% of Polyphenon E subjects versus 36.4% of placebo patients experienced a decrease after intervention (p=0.15). The 8OHdG to dG ratio, a marker of oxidative DNA damage, showed a greater mean decrease for those on Polyphenon E but this again did not reach statistical significance (−0.79 ±6.75 versus 1.81±8.37, p=0.17). The percentage of those with a decrease in 8OHdG was 65.0% versus 35.3% for those on Polyphenon E and placebo, respectively (p=0.10). Serum insulin-like growth factor-1 (IGF-1) levels, which have been correlated with increased prostate cancer risk, showed a greater decrease among those on Polyphenon E but this did not reach statistical significance (−6.90 ±20.97 versus −1.20±21.82 ng/ml, p=0.53). The proportion of subjects with a decrease in IGF-1 was likewise greater in those on Polyphenon E (54.2% versus 36.4%, p=0.25). Levels of insulin-like growth factor binding protein-3 (IGFBP-3), which modulates the bioavailability and ligand function of IGF-1, showed a greater but non-statistically significant increase in subjects on Polyphenon E intervention (20.38±289.3 versus −74.76±238.11 ng/ml, p=0.24). The proportion of those who had an increase in IGFBP-3 levels was 54.2% versus 36.4% for Polyphenon E and placebo subjects, respectively (p=0.25). The ratio of IGF-1 to IGFBP-3 similarly showed a favorable but non-significant decrease for the treatment arm (−0.003±0.011 versus 0.002±0.012, p=0.16, and 62.5% versus 45.5% showing a decrease, p=0.37).
Intervention induced changes in systemic biomarkers
summarizes the IHC data on tissue biomarker endpoints determined in the prostatectomy tissue. Tissue levels of the cellular marker for proliferation, Ki-67, did not differ significantly between the Polyphenon E and placebo arms (5.65±9.47 versus 4.37±6.11 % staining, p=0.68). We measured apoptosis by determining the percentage of cells staining for cleaved caspase 3 and found no difference between the two arms (0.39±0.57 versus 0.46±0.64, p=0.29, respectively). Angiogenesis, as measured by determining microvessel density was similar between the Polyphenon E and placebo groups (22.43±9.93 versus 23.04±10.40 average number of microvessels in five random 40× fields, p=0.89).
Tissue biomarkers in prostatectomy specimens
A greater proportion of subjects on Polyphenon E showed a decrease in Gleason score between prostate biopsy and surgical specimens but this again did not reach statistical significance (20.8% versus 8.3% showing a decrease, p=0.22 for those on Polyphenon E versus placebo). 16.7% of Polyphenon E and 37.5% of placebo subjects experienced an increase in Gleason score.