Methodological Issues in Conducting Pilot Trials in Chronic Pain as Randomized, Double-blind, Placebo-controlled Studies

BACKGROUND

The efficacy of tapentadol extended release (ER) for managing chronic pain has been demonstrated in large-scale, randomized, controlled, phase 3 studies (N=318-1,030) in patients with chronic osteoarthritis (OA) pain, low back pain (LBP), and pain related to diabetic peripheral neuropathy (DPN), which led to registration in many regions, including the United States and Europe. 2 pilot 12-week, randomized, double-blind, placebo-controlled phase 2 studies of tapentadol ER for chronic pain (OA knee pain or LBP, n=91; DPN or peripheral herpetic neuralgia [PHN] pain; n=91) were conducted in Japan. These small exploratory studies were substantially underpowered compared with the registration trials.

METHODS

Patients in both studies were randomized (2:1) to tapentadol ER (25-250 mg) or placebo for 12 weeks (≤6-week titration plus maintenance periods).

RESULTS

For the primary efficacy endpoint (change in pain intensity from baseline to last week of treatment; last observation carried forward), both studies failed to differentiate between tapentadol ER and placebo; least-squares mean differences (95% confidence intervals) for tapentadol ER vs. placebo were -0.1 (-1.04, 0.80) in the OA/LBP study and -0.1 (-1.10, 0.99) in the DPN/PHN study. More than 80% of patients took concomitant analgesics during these studies. Tapentadol was well tolerated.

CONCLUSIONS

Both studies were associated with methodological issues, including populations with different disease entities, small sample sizes, use of concomitant analgesics, and possible placebo effect that may have led to the failure to differentiate between tapentadol ER and placebo.

A randomized controlled trial comparing a prepackaged low-residue diet with a restricted diet for colonoscopy preparation: the impact on the results of colonoscopy in adenoma detection

AIM

This study aimed to investigate the clinical utility of a prepackaged low-residue diet (PLD) compared with a restricted diet (RD) for colonoscopic bowel preparation.

METHOD

A prospective randomized controlled trial was carried out with patients undergoing colonoscopy. One hundred patients were randomly assigned to PLD and RD groups. In the RD group, the patients received an information sheet containing acceptable low-residue options and instructions from the medical staff. All patients received 10 ml sodium picosulphate the day before colonoscopy and 1 l of polyethylene glycol with ascorbic acid (PEG-A) on the day of the colonoscopy. If the bowel preparation was not adequate, an additional PEG-A solution was given. The primary outcome was the efficacy of colonic cleansing as rated by the Boston Bowel Preparation Scale (BBPS). The additional amount of PEG-A solution, adenoma detection rate and patient tolerance were assessed as secondary outcomes.

RESULTS

The BBPS score in the PLD group was 7.3 ± 1.7 compared with 6.5 ± 1.7 in the RD group. The quality of bowel preparation was significantly better in the PLD group (P < 0.05). The mean amount of additional PEG-A solution in the PLD group was smaller than in the RD group (293.8 ± 474.8 vs 444.1 ± 625.0 ml), but there was no statistical difference between the two groups. Adenoma detection rates and patient tolerance were similar in the two groups.

CONCLUSION

Prepackaged low-residue diets PLD is superior to RD for bowel preparation for colonoscopy.

Exosomal microRNA in serum is a novel biomarker of recurrence in human colorectal cancer

Background:

Functional microRNAs (miRNAs) in exosomes have been recognised as potential stable biomarkers in cancers. The aim of this study is to identify specific miRNAs in exosome as serum biomarkers for the early detection of recurrence in human colorectal cancer (CRC).

Methods:

Serum samples were sequentially obtained from six patients with and without recurrent CRC. The miRNAs were purified from exosomes, and miRNA microarray analysis was performed. The miRNA expression profiles and copy number aberrations were explored using microarray and array CGH analyses in 124 CRC tissues. Then, we validated exosomal miRNAs in 2 serum sample sets (90 and 209 CRC patients) by quantitative real-time RT–PCR.

Results:

Exosomal miR-17-92a cluster expression level in serum was correlated with the recurrence of CRC. Exosomal miR-19a expression levels in serum were significantly increased in patients with CRC as compared with healthy individuals with gene amplification. The CRC patients with high exosomal miR-19a expression showed poorer prognoses than the low expression group (P<0.001).

Conclusions:

Abundant expression of exosomal miR-19a in serum was identified as a prognostic biomarker for recurrence in CRC patients.

Performance of the EuroSCORE II and the Society of Thoracic Surgeons Score in patients undergoing aortic valve replacement for aortic stenosis

Aim. The aim of this study was to evaluate the performance of the new European System for Cardiac Operative Risk Evaluation (EuroSCORE) II and the Society of Thoracic Surgeons (STS) score in patients undergoing aortic valve replacement (AVR) for aortic stenosis (AS). This study also evaluated the performance of the EuroSCORE II in high-risk patients. Methods. Three hundred and six consecutive adult patients underwent AVR with or without coronary artery bypass grafting at our institution from August 2002 to June 2012. The cut-off value of 6% for the EuroSCORE II and 10% for the STS score was used to identify high-risk in this study. Results. Operative mortality was 3.5% (N.=11). The mean expected mortality for all patients was 3.1% (O/E ratio=1.12) for the EuroSCORE II and 5.1% (O/E ratio=0.68) for the STS score. Observed versus expected mortality for the high-risk patients was 17.2% versus 11.9% (O/E ratio=1.44) for the EuroSCORE II (N.=29) and 19.3% versus 18.5% (O/E ratio=1.04) for the STS score (N.=31), and that for the low-risk was 2.1% versus 2.2% (O/E ratio=0.95) for the EuroSCORE II and 1.8% versus 3.5% (O/E ratio=0.51) for the STS score. Discrimination power of the STS score was good (area under the receiver operating characteristics curve [AUC] 0.74), but that of the EuroSCORE II was suboptimal (AUC 0.66). Conclusion. Good calibration ability of the EuroSCORE II for low-risk patients and that of the STS score for high-risk are observed. However, the EuroSCORE II underestimates the operative mortality in high-risk patients and the STS score overestimates the risk in low-risk patients.

NFκB2 Gene as a Novel Candidate that Epigenetically Responds to Interval Walking Training

Physical fitness has been reported to decrease the risk of lifestyle-related diseases. The present study evaluated genome-wide methylation under the hypothesis that interval walking training (IWT) imparted beneficial effects on health, particularly by epigenetically ameliorating susceptibility to inflammation. We screened DNA from peripheral blood samples via genome-wide microarray for genes whose methylation was affected by IWT, paying special attention to promoter regions, and identified over 40 hyper- or hypo-methylated genes following IWT that were not witnessed in controls. We next selected genes in which the degree of methylation change in the promoter region was correlated with energy consumption following IWT. In this way, we found the NFκB2 gene to have increased methylation in multiple regions of its promoter sequence following participation in an exercise regimen. Next, IWT-induced NFκB2 hyper-methylation was confirmed by a quantitative PyroSequencing assessment of methylation in samples obtained from independent subjects who also underwent IWT. The increase in NFκB2 gene promoter methylation by IWT indicates that this regimen may suppress pro-inflammatory cytokines. Thus, these results provide an additional line of evidence that IWT is advantageous in promoting health from an epigenetic perspective by ameliorating susceptibility to inflammation.