Philipp Dahm

GRADE guidelines: 1. Introduction—GRADE evidence profiles and summary of findings tables

This article is the first of a series providing guidance for use of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system of rating quality of evidence and grading strength of recommendations in systematic reviews, health technology assessments (HTAs), and clinical practice guidelines addressing alternative management options. The GRADE process begins with asking an explicit question, including specification of all important outcomes. After the evidence is collected and summarized, GRADE provides explicit criteria for rating the quality of evidence that include study design, risk of bias, imprecision, inconsistency, indirectness, and magnitude of effect. Recommendations are characterized as strong or weak (alternative terms conditional or discretionary) according to the quality of the supporting evidence and the balance between desirable and undesirable consequences of the alternative management options. GRADE suggests summarizing evidence in succinct, transparent, and informative summary of findings tables that show the quality of evidence and the magnitude of relative and absolute effects for each important outcome and/or as evidence profiles that provide, in addition, detailed information about the reason for the quality of evidence rating. Subsequent articles in this series will address GRADEs approach to formulating questions, assessing quality of evidence, and developing recommendations.

GRADE guidelines: 9. Rating up the quality of evidence.

The most common reason for rating up the quality of evidence is a large effect. GRADE suggests considering rating up quality of evidence one level when methodologically rigorous observational studies show at least a two-fold reduction or increase in risk, and rating up two levels for at least a five-fold reduction or increase in risk. Systematic review authors and guideline developers may also consider rating up quality of evidence when a dose-response gradient is present, and when all plausible confounders or biases would decrease an apparent treatment effect, or would create a spurious effect when results suggest no effect. Other considerations include the rapidity of the response, the underlying trajectory of the condition, and indirect evidence.

Enhancement of vaccine-mediated antitumor immunity in cancer patients after depletion of regulatory T cells

In this study, we investigated whether elimination of CD4+/CD25+ Tregs using the recombinant IL-2 diphtheria toxin conjugate DAB(389)IL-2 (also known as denileukin diftitox and ONTAK) is capable of enhancing the immunostimulatory efficacy of tumor RNA-transfected DC vaccines. We show that DAB(389)IL-2 is capable of selectively eliminating CD25-expressing Tregs from the PBMCs of cancer patients without inducing toxicity on other cellular subsets with intermediate or low expression of CD25. DAB(389)IL-2-mediated Treg depletion resulted in enhanced stimulation of proliferative and cytotoxic T cell responses in vitro but only when DAB(389)IL-2 was omitted during T cell priming. DAB(389)IL-2 significantly reduced the number of Tregs present in the peripheral blood of metastatic renal cell carcinoma (RCC) patients and abrogated Treg-mediated immunosuppressive activity in vivo. Moreover, DAB(389)IL-2-mediated elimination of Tregs followed by vaccination with RNA-transfected DCs significantly improved the stimulation of tumor-specific T cell responses in RCC patients when compared with vaccination alone. Our findings may have implications in the design of immune-based strategies that may incorporate the Treg depletion strategy to achieve potent antitumor immunity with therapeutic impact.

GRADE guidelines: 7. Rating the quality of evidence--inconsistency

This article deals with inconsistency of relative (rather than absolute) treatment effects in binary/dichotomous outcomes. A body of evidence is not rated up in quality if studies yield consistent results, but may be rated down in quality if inconsistent. Criteria for evaluating consistency include similarity of point estimates, extent of overlap of confidence intervals, and statistical criteria including tests of heterogeneity and I(2). To explore heterogeneity, systematic review authors should generate and test a small number of a priori hypotheses related to patients, interventions, outcomes, and methodology. When inconsistency is large and unexplained, rating down quality for inconsistency is appropriate, particularly if some studies suggest substantial benefit, and others no effect or harm (rather than only large vs. small effects). Apparent subgroup effects may be spurious. Credibility is increased if subgroup effects are based on a small number of a priori hypotheses with a specified direction; subgroup comparisons come from within rather than between studies; tests of interaction generate low P-values; and have a biological rationale.

Autologous dendritic cells transfected with prostate-specific antigen RNA stimulate CTL responses against metastatic prostate tumors

Autologous dendritic cells (DCs) transfected with mRNA encoding prostate-specific antigen (PSA) are able to stimulate potent, T cell-mediated antitumor immune responses in vitro. A phase I trial was performed to evaluate this strategy for safety, feasibility, and efficacy to induce T cell responses against the self-protein PSA in patients with metastatic prostate cancer. In 13 study subjects, escalating doses of PSA mRNA-transfected DCs were administered with no evidence of dose-limiting toxicity or adverse effects, including autoimmunity. Induction of PSA-specific T cell responses was consistently detected in all patients, suggesting in vivo bioactivity of the vaccine. Vaccination was further associated with a significant decrease in the log slope PSA in six of seven subjects; three patients that could be analyzed exhibited a transient molecular clearance of circulating tumor cells. The demonstration of vaccine safety, successful in vivo induction of PSA-specific immunity, and impact on surrogate clinical endpoints provides a scientific rationale for further clinical investigation of RNA-transfected DCs in the treatment of human cancer.

Telomerase mRNA-Transfected Dendritic Cells Stimulate Antigen-Specific CD8+ and CD4+ T Cell Responses in Patients with Metastatic Prostate Cancer

Telomerase reverse transcriptase (hTERT) represents an attractive target for cancer immunotherapy because hTERT is reactivated in most human tumors. A clinical trial was initiated in which hTERT mRNA-transfected dendritic cells (DC) were administered to 20 patients with metastatic prostate cancer. Nine of these subjects received DC transfected with mRNA encoding a chimeric lysosome-associated membrane protein-1 (LAMP) hTERT protein, allowing for concomitant induction of hTERT-specific CD8+ and CD4+ T cell responses. Treatment was well tolerated. Intense infiltrates of hTERT-specific T cells were noted at intradermal injection sites after repeated vaccination. In 19 of 20 subjects, expansion of hTERT-specific CD8+ T cells was measured in the peripheral blood of study subjects, with 0.9–1.8% of CD8+ T cells exhibiting Ag specificity. Patients immunized with the chimeric LAMP hTERT vaccine developed significantly higher frequencies of hTERT-specific CD4+ T cells than subjects receiving DC transfected with the unmodified hTERT template. Moreover, CTL-mediated killing of hTERT targets was enhanced in the LAMP hTERT group, suggesting that an improved CD4+ response could augment a CTL response. Vaccination was further associated with a reduction of prostate-specific Ag velocity and molecular clearance of circulating micrometastases. Our findings provide a rationale for further development of hTERT-transfected DC vaccines in the treatment of prostate and other cancers.

GRADE guidelines: 11. Making an overall rating of confidence in effect estimates for a single outcome and for all outcomes

GRADE requires guideline developers to make an overall rating of confidence in estimates of effect (quality of evidence-high, moderate, low, or very low) for each important or critical outcome. GRADE suggests, for each outcome, the initial separate consideration of five domains of reasons for rating down the confidence in effect estimates, thereby allowing systematic review authors and guideline developers to arrive at an outcome-specific rating of confidence. Although this rating system represents discrete steps on an ordinal scale, it is helpful to view confidence in estimates as a continuum, and the final rating of confidence may differ from that suggested by separate consideration of each domain. An overall rating of confidence in estimates of effect is only relevant in settings when recommendations are being made. In general, it is based on the critical outcome that provides the lowest confidence.

A retrospective comparison of anesthetic management of robot-assisted laparoscopic radical prostatectomy versus radical retropubic prostatectomy

STUDY OBJECTIVE To compare anesthetic management and postoperative outcomes in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALP) and radical retropubic prostatectomy (RRP) with general anesthesia. DESIGN Retrospective database study of RALP and RRP patients at Duke University Medical Center from 6/2003 to 6/2006. SETTING University teaching hospital. PATIENTS 541 ASA physical status I, II, and III men, 280 of whom were RRP patients and 256 RALP patients. MEASUREMENTS Patient demographics, intraoperative fluids and blood products, hemodynamic parameters, pain scores in the Postanesthesia Care Unit (PACU), intraoperative and postoperative analgesic consumption, need for rescue antiemetics in the PACU, and intraoperative use of vasopressors and antihypertensives, were all recorded. Additional data included postoperative transfusion data; clinical status of the patients cancer preoperatively and postoperatively; hematocrit, platelet count, and creatinine levels; and length of hospital stay. MAIN RESULTS Estimated blood loss (EBL) was higher for RRP than RALP patients (mean +/- SD; 1,087 +/- 853 mL vs. 287 +/- 317 mL; P < 0.0001). Likewise, 24% of RRP patients received red blood cell (RBC) transfusions intraoperatively, compared with 0.4% RALP patients (P < 0.0001). Intraoperatively, RALP patients received more antihypertensive agents (37% vs. 21%; P < 0.0001), and fewer vasopressors (63% vs. 78%; P < 0.0001) than did RRP patients. The two groups had similar morphine-equivalent opioid use intraoperatively, but in the PACU, RALP patients required fewer morphine equivalents (mean +/- SD; 11.4 +/- 7.7 mg vs. 14.9 +/- 9.8 mg; P < 0.0001). The RALP patients had longer surgical times (mean +/- SD; 296 +/- 76 vs.193 +/- 69 min; P < 0.0001) but shorter PACU stays (mean +/- SD; 113 +/- 55 min vs. 143 +/- 58 min; P < 0.0001) and shorter hospital stays (mean +/- SD; 44 +/- 77 hrs vs. 56 +/- 26 hrs; P = 0.009). CONCLUSIONS Duration of surgery was greater with RALP, but it was associated with less EBL, fewer transfusions of blood products, and shorter PACU and hospital stays.

Screening for prostate cancer: systematic review and meta-analysis of randomised controlled trials

Objective To examine the evidence on the benefits and harms of screening for prostate cancer. Design Systematic review and meta-analysis of randomised controlled trials. Data sources Electronic databases including Medline, Embase, CENTRAL, abstract proceedings, and reference lists up to July 2010. Review methods Included studies were randomised controlled trials comparing screening by prostate specific antigen with or without digital rectal examination versus no screening. Data abstraction and assessment of methodological quality with the GRADE approach was assessed by two independent reviewers and verified by the primary investigator. Mantel-Haenszel and inverse variance estimates were calculated and pooled under a random effects model expressing data as relative risks and 95% confidence intervals. Results Six randomised controlled trials with a total of 387 286 participants that met inclusion criteria were analysed. Screening was associated with an increased probability of receiving a diagnosis of prostate cancer (relative risk 1.46, 95% confidence interval 1.21 to 1.77; P<0.001) and stage I prostate cancer (1.95, 1.22 to 3.13; P=0.005). There was no significant effect of screening on death from prostate cancer (0.88, 0.71 to 1.09; P=0.25) or overall mortality (0.99, 0.97 to 1.01; P=0.44). All trials had one or more substantial methodological limitations. None provided data on the effects of screening on participants’ quality of life. Little information was provided about potential harms associated with screening. Conclusions The existing evidence from randomised controlled trials does not support the routine use of screening for prostate cancer with prostate specific antigen with or without digital rectal examination.

Human Dendritic Cells Transfected with RNA Encoding Prostate-Specific Antigen Stimulate Prostate-Specific CTL Responses In Vitro

Although immunological tolerance to self Ags represents an important mechanism to prevent normal tissue injury, there is growing evidence that tolerance to tumor Ags, which often represent normal peripherally expressed proteins, is not absolute and can be effectively reverted. Prostate-specific Ag (PSA) is a self Ag expressed by both normal and malignant prostatic epithelium, and therefore offers a unique opportunity to examine the ability of self Ags to serve as specific CTL targets. In this study, we investigated the efficacy of autologous dendritic cells (DC) transfected with mRNA encoding PSA to stimulate CTL against PSA Ags in vitro. Ag in form of RNA carries the advantage to encode multiple epitopes for many HLA alleles, thus permitting induction of CTL responses among many cancer patients independent of their HLA repertoire. In this study, we show that PSA mRNA-transfected DC were capable of stimulating primary CTL responses against PSA Ags in vitro. The PSA-specific CTL did not cross-react with kallikrein Ags, a protein, which shares significant homology with PSA, suggesting that harmful autoimmune toxicity may not represent a significant problem with this approach. PSA RNA-transfected DC generated from male or female healthy volunteers or from cancer patients were equally effective in stimulating PSA-specific CTL in vitro, implying that neither natural tolerance to PSA Ags nor tumor-mediated T cell anergy may represent major barriers for CTL generation against the self Ag PSA. This study provides a preclinical rationale for using PSA RNA-transfected DC in active or adoptive immunization protocols.