Treatment success in cancer: industry compared to publicly sponsored randomized controlled trials

The Benefits and Risks of Receiving Investigational Solid Tumor Drugs in Randomized Trials : A Systematic Review and Meta-analysis

BACKGROUND

Many patients participate in cancer trials to access new therapies. The extent to which new treatments produce clinical benefit for trial participants is unclear.

PURPOSE

To estimate the progression-free survival (PFS) and overall survival (OS) advantage of assignment to experimental groups in randomized trials for 6 solid tumors.

DATA SOURCES

ClinicalTrials.gov was searched for trials of investigational drugs with results posted between 2017 and 2021.

STUDY SELECTION

Investigational drugs were defined as those not yet having full approval from the U.S. Food and Drug Administration for the study indication. Trials were included if they were randomized and tested drugs or biologics.

DATA EXTRACTION

Data extraction was completed by 2 independent reviewers. Data were pooled using a random-effects model.

DATA SYNTHESIS

The sample included 128 trials comprising 141 comparisons of a new drug and a comparator. These comparisons included 47 050 patients. The pooled hazard ratio for PFS was 0.80 (95% CI, 0.75 to 0.85), indicating statistically significant benefit for patients in experimental groups. This corresponded to a median PFS advantage of 1.25 months (CI, 0.80 to 1.68 months). The pooled hazard ratio for OS was 0.92 (CI, 0.88 to 0.95), corresponding to a survival gain of 1.18 months (CI, 0.72 to 1.71 months). The absolute risk for a serious adverse event for comparator group patients was 29.56% (CI, 26.64% to 32.65%), with an increase in risk of 7.40% (CI, 5.66% to 9.14%) for patients in experimental groups.

LIMITATIONS

Trials in this sample were heterogeneous. Comparator group interventions were assumed to reflect standard of care.

CONCLUSION

Assignment to experimental groups produces statistically significant survival gains. However, the absolute survival gain is small, and toxicity is statistically significantly greater. The findings of this review provide reassuring evidence that patients are not meaningfully disadvantaged by assignment to comparator groups.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research.

Accuracy of Event Rate and Effect Size Estimation in Major Cardiovascular Trials: A Systematic Review

Importance

For the design of a randomized clinical trial (RCT), estimation of the expected event rate and effect size of an intervention is needed to calculate the sample size. Overestimation may lead to an underpowered trial.

Objective

To evaluate the accuracy of published estimates of event rate and effect size in contemporary cardiovascular RCTs.

Evidence Review

A systematic search was conducted in MEDLINE for multicenter cardiovascular RCTs associated with MeSH (Medical Subject Headings) terms for cardiovascular diseases published in the New England Journal of Medicine, JAMA, or the Lancet between January 1, 2010, and December 31, 2019. Identified trials underwent abstract review; eligible trials then underwent full review, and those with insufficiently reported data were excluded. Data were extracted from the original publication or the study protocol, and a random-effects model was used for data pooling. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline. The primary outcome was the accuracy of event rate and effect size estimation. Accuracy was determined by comparing the observed event rate in the control group and the effect size with their hypothesized values. Linear regression was used to determine the association between estimation accuracy and trial characteristics.

Findings

Of the 873 RCTs identified, 374 underwent full review and 30 were subsequently excluded, resulting in 344 trials for analysis. The median observed event rate was 9.0% (IQR, 4.3% to 21.4%), which was significantly lower than the estimated event rate of 11.0% (IQR, 6.0% to 25.0%) with a median deviation of -12.3% (95% CI, -16.4% to -5.6%; P < .001). More than half of the trials (196 [61.1%]) overestimated the expected event rate. Accuracy of event rate estimation was associated with a higher likelihood of refuting the null hypothesis (0.13 [95% CI, 0.01 to 0.25]; P = .03). The median observed effect size in superiority trials was 0.91 (IQR, 0.74 to 0.99), which was significantly lower than the estimated effect size of 0.72 (IQR, 0.60 to 0.80), indicating a median overestimation of 23.1% (95% CI, 17.9% to 28.3%). A total of 216 trials (82.1%) overestimated the effect size.

Conclusions and Relevance

In this systematic review of contemporary cardiovascular RCTs, event rates of the primary end point and effect sizes of an intervention were frequently overestimated. This overestimation may have contributed to the inability to adequately test the trial hypothesis.

Understanding common key indicators of successful and unsuccessful cancer drug trials using a contrast mining framework on ClinicalTrials.gov

Clinical trials are essential to the process of new drug development. As clinical trials involve significant investments of time and money, it is crucial for trial designers to carefully investigate trial settings prior to designing a trial. Utilizing trial documents from ClinicalTrials.gov, we aim to understand the common characteristics of successful and unsuccessful cancer drug trials to provide insights about what to learn and what to avoid. In this research, we first computationally classified cancer drug trials into successful and unsuccessful cases and then utilized natural language processing to extract eligibility criteria information from the trial documents. To provide explainable and potentially modifiable recommendations for new trial design, contrast mining was applied to discoverhighly contrasted patterns with a significant difference in prevalence between successful (completion with advancement to the next phase) and unsuccessful (suspended, withdrawn, or terminated) groups. Our method identified contrast patterns consisting of combinations of drug categories, eligibility criteria, study organization, and study design for nine major cancers. In addition to a literature review for the qualitative validation of mined contrast patterns, we found that contrast-pattern-based classifiers using the top 200 contrast patterns as feature representations can achieve approximately 80% F₁ score for eight out of ten cancer types in our experiments. In summary, aligning with the modernization efforts of ClinicalTrials.gov, our study demonstrates that understanding the contrast characteristics of successful and unsuccessful cancer trials may provide insights into the decision-making process for trial investigators and therefore facilitate improved cancer drug trial design.

The Impact of Industry Funding on Randomized Controlled Trials of Biologic Therapies

Background: There has been substantial interest from the pharmaceutical industry to study and develop new biologic agents. Previous studies outside of the biologics field have demonstrated that industry funding has the potential to impact the design and findings of clinical trials. The objective of this study was to evaluate the impact of industry funding on randomized controlled trials (RCTs) that investigated the efficacy of biologic therapies. Methods: A review of all RCTs involving biologic therapies in top impact factor medical journals from January 2018 to December 2020 was performed. The relationship between industry funding and the presence of statistically significant primary outcomes and the use of active comparators were analyzed. Results: Among the 157 RCTs included, 120 (76%) were industry funded and 37 (24%) declared no industry funding. Industry-funded studies were significantly more likely to report a statistically significant positive primary outcome compared to studies without industry funding (85% vs. 67%, χ² = 5.867, p = 0.015) and were significantly more likely to utilize placebo or no comparator than non-industry-funded trials (78% vs. 49%, χ² = 4.430, p = 0.035). Conclusions: Industry-funded trials investigating biologic therapies are more likely to yield statistically significant positive outcomes and use placebo comparators when compared to non-industry-funded biologic therapy trials in high-impact medical journals.

IDENTIFICATION OF THRESHOLD FOR LARGE (DRAMATIC) EFFECTS THAT WOULD OBVIATE RANDOMIZED TRIALS IS NOT POSSIBLE

OBJECTIVE

To analyze distribution of "dramatic", large treatment effects.

STUDY DESIGN & SETTING

Pareto distribution modeling of previously reported cohorts of 3,486 randomized trials (RCTs) that enrolled 1,532,459 patients and 730 non-randomized studies (NRS) enrolling 1,650,658 patients.

RESULTS

We calculated the Pareto α parameter, which determines the tail of the distribution for various starting points of distribution [odds ratio_min (OR_min)]. In default analysis using all data at OR_min ≥1, Pareto distribution fit well to the treatment effects of RCTs favoring the new treatments (P = 0.21, Kolmogorov-Smirnov test) with best α = 2.32. For NRS, Pareto fit for OR_min ≥2 with best α = 1.91. For RCTs, theoretical 99th percentile OR was 32.7. The actual 99th percentile OR was 25; which converted into relative risk (RR) = 7.1. The maximum observed effect size was OR = 121 (RR = 11.45). For NRS, theoretical 99th percentile was OR = 315. The actual 99th percentile OR was 294 (RR = 13). The maximum observed effect size was OR = 1473 (RR = 66).

CONCLUSIONS

The effects sizes observed in RCTs and NRS considerably overlap. Large effects are rare and there is no clear threshold for dramatic effects that would obviate future RCTs.

Design of placebo-controlled randomized trials of anticancer agents: Ethical considerations based on a review of published trials

BACKGROUND

Limited information exists about the design of placebo-controlled cancer trials. Through a systematic review of trials published in 2013, we describe placebo use in randomized trials testing anticancer agents and analyze strategies that increase exposure to the experimental regimen.

METHODS

Trials were classified as add-on (placebo in combination with standard treatment) or placebo-only. Strategies to allow more than half of the participants to receive the experimental regimen were reviewed. The risk-benefit ratio of receiving the experimental agent was considered favorable if the difference in primary outcome was significant (p ≤ 0.05), neutral if there was no significant difference in the primary outcome and the experimental agent did not add substantial toxicity, and unfavorable otherwise.

RESULTS

Eighty trials were included (32,694 participants). Most trials were add-on (69%). The risk-benefit outcome was favorable, neutral, and unfavorable to the experimental agent in 52%, 32%, and 16% of placebo-only trials and 25%, 53%, and 22%, respectively, of add-on trials. Four strategies increased exposure to the experimental regimen: one-way crossover (23%), uneven randomization (21%), three-arms (13%), and randomized discontinuation design (4%); these strategies were used more often in placebo-only trials.

CONCLUSION

A minority of participants received placebo alone and strategies to increase experimental exposure were used commonly. Fewer than half of the studies had favorable outcomes, thus defending the use of placebo controls, when there is no established treatment. Strategies that increase patient exposure to experimental agents rather than placebo may expose them to non-beneficial, sometimes toxic, experimental agents.

Challenges of independent clinical research

Pharmaceutical companies fund most clinical trials on drugs. However, there are clinical issues that might not be a priority from a commercial point of view, but that should certainly be addressed, given their importance for patients and society in general. Independent clinical research represents a fundamental pillar here and its basic element is investigator-initiated studies/trials. In these studies, it is the researcher who conceives the idea, develops the project and also acts as the sponsor. Most researchers are familiar with participating as collaborators in studies sponsored by pharmaceutical companies. In these studies, the company is in charge of all the scientific, legal and financial aspects, leaving the responsibility of the researcher mainly limited to the inclusion of patients and compliance with the protocol. On the contrary, the start-up and development of an independent research study requires considerable resources - of knowledge, money and time - and careful planning on the part of the researcher. In this manuscript, we will review the main characteristics of the studies initiated by the researcher and their fundamental differences with those sponsored by the pharmaceutical industry. We will also outline what its strengths and limitations are. Finally, we will propose some solutions to the main challenges they pose. Our ultimate goal is to stimulate potential researchers to undertake the challenge of conducting an independent clinical research project.

Characteristics of Drug Intervention Clinical Trials and Scientific Impact of the Trial Outcome: A Bibliometric Analysis Using the Relative Citation Ratio in Non-small Cell Lung Cancer from 2007 to 2016

BACKGROUND

Although a large number of clinical trials have been conducted, the types of clinical trials that are scientifically influential, frequently utilized by society, and contribute to the progress of evidence-based medicine (EBM) have not been studied. Thus, we aimed to investigate the relationship between the characteristics of clinical trials and the scientific impact of the outcome in non-small cell lung cancer (NSCLC) by performing a bibliometric analysis using relative citation ratio (RCR), a newly developed bibliometric index by the National Institutes of Health (NIH).

METHODS

Primary publications of drug intervention clinical trials for NSCLC between 2007 and 2016 were included in the study. The characteristics of clinical trials were compared among four RCR categories with 50 trials in each [LOW50, 50 NIH percentile (50NIH%ile), 95 NIH percentile (95NIH%ile), and TOP50], totaling to 200 trials.

RESULTS

Median RCRs of LOW50, 50NIH%ile, 95NIH%ile, and TOP50 were 0.03, 1.00, 5.76, and 26.89, respectively. Publications of Phase 3, randomized, blinded, for-profit-company supported/sponsored, multi-center trials, and trials with a larger number of subjects were shown to have a higher scientific impact. Publications of clinical trials of newly developed molecular target drugs, including epidermal growth factor receptor-tyrosine kinase inhibitors, anaplastic lymphoma kinase inhibitors, and immune checkpoint inhibitors demonstrated a higher scientific impact than those of traditional chemotherapies.

CONCLUSION

Clinical trials designed to have a high evidence level would improve the scientific impact of the outcome, and novel interventions would be another factor to improve the clinical trials' influence.

Industry sponsorship and research outcome

BACKGROUND

Clinical research affecting how doctors practice medicine is increasingly sponsored by companies that make drugs and medical devices. Previous systematic reviews have found that pharmaceutical-industry sponsored studies are more often favorable to the sponsor's product compared with studies with other sources of sponsorship. A similar association between sponsorship and outcomes have been found for device studies, but the body of evidence is not as strong as for sponsorship of drug studies. This review is an update of a previous Cochrane review and includes empirical studies on the association between sponsorship and research outcome.

OBJECTIVES

To investigate whether industry sponsored drug and device studies have more favorable outcomes and differ in risk of bias, compared with studies having other sources of sponsorship.

SEARCH METHODS

In this update we searched MEDLINE (2010 to February 2015), Embase (2010 to February 2015), the Cochrane Methodology Register (2015, Issue 2) and Web of Science (June 2015). In addition, we searched reference lists of included papers, previous systematic reviews and author files.

SELECTION CRITERIA

Cross-sectional studies, cohort studies, systematic reviews and meta-analyses that quantitatively compared primary research studies of drugs or medical devices sponsored by industry with studies with other sources of sponsorship. We had no language restrictions.

DATA COLLECTION AND ANALYSIS

Two assessors screened abstracts and identified and included relevant papers. Two assessors extracted data, and we contacted authors of included papers for additional unpublished data. Outcomes included favorable results, favorable conclusions, effect size, risk of bias and whether the conclusions agreed with the study results. Two assessors assessed risk of bias of included papers. We calculated pooled risk ratios (RR) for dichotomous data (with 95% confidence intervals (CIs)).

MAIN RESULTS

Twenty-seven new papers were included in this update and in total the review contains 75 included papers. Industry sponsored studies more often had favorable efficacy results, RR: 1.27 (95% CI: 1.17 to 1.37) (25 papers) (moderate quality evidence), similar harms results RR: 1.37 (95% CI: 0.64 to 2.93) (four papers) (very low quality evidence) and more often favorable conclusions RR: 1.34 (95% CI: 1.19 to 1.51) (29 papers) (low quality evidence) compared with non-industry sponsored studies. Nineteen papers reported on sponsorship and efficacy effect size, but could not be pooled due to differences in their reporting of data and the results were heterogeneous. We did not find a difference between drug and device studies in the association between sponsorship and conclusions (test for interaction, P = 0.98) (four papers). Comparing industry and non-industry sponsored studies, we did not find a difference in risk of bias from sequence generation, allocation concealment, follow-up and selective outcome reporting. However, industry sponsored studies more often had low risk of bias from blinding, RR: 1.25 (95% CI: 1.05 to 1.50) (13 papers), compared with non-industry sponsored studies. In industry sponsored studies, there was less agreement between the results and the conclusions than in non-industry sponsored studies, RR: 0.83 (95% CI: 0.70 to 0.98) (six papers).

AUTHORS' CONCLUSIONS

Sponsorship of drug and device studies by the manufacturing company leads to more favorable efficacy results and conclusions than sponsorship by other sources. Our analyses suggest the existence of an industry bias that cannot be explained by standard 'Risk of bias' assessments.

Impact of industry collaboration on randomised controlled trials in oncology

BACKGROUND

Industry funders can simply provide money or collaborate in trial design, analysis or reporting of clinical trials. Our aim was to assess the impact of industry collaboration on trial methodology and results of randomised controlled trials (RCT).

METHODS

We searched PubMed for oncology RCTs published May 2013 to December 2015 in peer-reviewed journals with impact factor > 5 requiring reporting of funder role. Two authors extracted methodologic (primary end-point; blinding of the patient, clinician and outcomes assessor; and analysis) and outcome data. We used descriptive statistics and two-sided Fisher exact tests to compare characteristics of trials with collaboration, with industry funding only, and without industry funding.

RESULTS

We included 224 trials. Compared to those without industry funding, trials with collaboration used more placebo control (RR 3·59, 95% CI [1·88-6·83], p < 0001), intention-to-treat analysis (RR 1·32, 95% CI [1·04-1·67], p = 02), and blinding of patients (RR 3·05, 95% CI [1·71-5·44], p < 0001), clinicians (RR 3·36, 95% CI [1·83-6·16], p≤·001) and outcomes assessors (RR 3·03, 95% CI [1·57-5·83], p = 0002). They did not differ in use of overall survival as a primary end-point (RR 1·27 95% CI [0·72-2·24]) and were similarly likely to report positive results (RR 1·11 95% CI [0·85-1·46], p = 0.45). Studies with funding only did not differ from those without funding.

CONCLUSIONS

Oncology RCTs with industry collaboration were more likely to use some high-quality methods than those without industry funding, with similar rates of positive results. Our findings suggest that collaboration is not associated with trial outcomes and that mandatory disclosure of funder roles may mitigate bias.

Network meta-analyses performed by contracting companies and commissioned by industry

BACKGROUND

Industry commissions contracting companies to perform network meta-analysis for health technology assessment (HTA) and reimbursement submissions. Our objective was to estimate the number of network meta-analyses performed by consulting companies contracted by industry, to assess whether they were published, and to explore reasons for non-publication.

METHODS

We searched MEDLINE for network meta-analyses of randomized trials. Papers were included if they had authors affiliated with any contracting company. All identified contracting companies as well as additional ones from the list of the exhibitors at the International Society for Pharmacoeconomics and Outcomes Research, an annual meeting that representatives from many contracting companies attend and exhibit at, were surveyed regarding conduct and publication of network meta-analyses.

RESULTS

In 162 of 822 (20%) network meta-analysis papers, authors were affiliated to 66 contracting companies. Another 36 contracting companies were identified by the exhibitors list. Three companies had no contact information and six merged with others, therefore 93 companies were contacted. Thirty seven out of ninety three (40%) companies responded, and 19 indicated that they had performed a total of 476 network meta-analyses, but only 102 (21%) papers were published. Thirteen companies that disclosed to have conducted 174 network meta-analyses (45 published) provided reasons for non-publication. Of the 129 still unpublished meta-analyses, for 40 there were plans for future publication, for 37 the sponsor did not allow publication, for 16 the contracting companies did not plan to publish the meta-analysis, for another 23 plans were unclear, and the remaining 13 were used as HTA submission. The protocol of the network meta-analysis was publically available from 11/162 (6.8%) network meta-analyses published by authors affiliated with contracting companies.

CONCLUSIONS

There is a prolific sector of professional contracting companies that perform network meta-analyses. Industry commissions many network meta-analyses, but most are not registered before or published after analyses in the scientific literature. Mechanisms to improve publication rates of network meta-analysis commissioned by industry are warranted.

Registered Randomized Trials Comparing Generic and Brand-Name Drugs: A Survey

OBJECTIVES

To evaluate the research agenda of registered randomized trials comparing generic and brand-name drugs in terms of who sponsors them, whether they are published promptly, and whether they find favorable results.

METHODS

We included randomized trials comparing the safety or efficacy of brand-name vs generic medications that were registered in ClinicalTrials.gov or other registries from January 1, 2000, through July 31, 2015. To identify published articles or results generated from such trials, we searched PubMed, Scopus, Google, and registry databases. Data were compared across sponsorship categories ("inbred" if the compared drugs were owned by the same company or its partners/subsidiaries, "competitive" if the compared drugs were owned by competing companies, and "apparently nonprofit"), and time to publication was evaluated with Cox analysis.

RESULTS

We found 207 registered protocols reporting on 186 completed trials. Among those trials, 37 had published their results and another 56 had posted results in registries, for a total of 93 trials with available results. Four years after trial completion, results were available for 64 of 138 trials (46.4%), with substantial differences by sponsor: 70.8% (34 of 48), 28.1% (18 of 64), and 46.2% (12 of 26) of the inbred, competitive, and nonprofit trials, respectively. In multivariate modeling, inbred trials had a 1.73-fold risk of having results available compared with competitive trials (P=.04). Almost all trials reported favorable results, with the exception of 4 (4.3% of the 93 trials with results).

CONCLUSION

Despite the importance of generic drugs, relatively few registered randomized trials have compared the health effects of generic vs brand-name medicines, and there is an associated unsatisfactory publication rate and almost ubiquitous favorable results. The overall literature on the topic is at high risk of bias, possibly in favor of generic drugs. Higher nonprofit funding and stronger pressure to register trials and publish results are needed.

A framework to assess the value of application of formal criteria to check clinical relevance in RCTs as part of a benefit assessment strategy

Recently, the topic of assessing clinical relevance on top of statistical significance in the analysis of randomized control trials (RCTs) has got increasing attention, in particular as part of benefit assessments. Several formal criteria to serve this purpose have been published. In this paper, we present a framework to assess the value of the application of such criteria. We propose to quantify the need for the assessment of clinical relevance by the actual risk of having accepted a benefit for a treatment with an irrelevant effect in a successful RCT. We then study how this risk can be controlled by two popular criteria based on comparing the effect estimate or the lower bound of the confidence interval with a given threshold. We further propose to quantify the impact of using formal criteria by considering the expected costs when specifying error-specific costs for each of the three possible types of errors: A benefit may be accepted for a treatment, which is actually inferior, or which is not inferior, but only implies an irrelevant improvement, or a benefit may be rejected for a treatment implying a relevant improvement. This way we can demonstrate that the impact depends on parameters which are typically not explicitly defined in the frame of benefit assessments. Depending on the values of these parameters, formal checks of clinical relevance may imply better decisions on average, but they may also imply more harm than good on average.

Strengths and limitations of industry vs. academic randomized controlled trials

Clinical research has evolved substantially over the last two decades, but industry-sponsored research is still substantially superior to academic research in preparing, organizing and monitoring studies. Academics have to realize that conducting clinical research has become a real job with professionalism requirements. The primary objectives of research and development clearly differ between industry and academics. In the first case, new drug development is expected to generate profit, whereas in the latter case, research is aimed at understanding mechanisms of disease, promoting evidence-based medicine, and improving public health and care. However, a large number of clinical studies do not achieve their goals, and the reasons for failure may also differ between sponsored and academic studies. Industry and academics should develop better constructive partnerships and learn from each other. Academics should guide industry in study design and in investigator site selection, and academics should benefit from industry's expertise in improving monitoring and reporting processes. Finally, the existing database from former studies should be opened and shared with academics, to enable the exploration of additional scientific questions and the generation of new hypotheses. The two types of research should not be opposed, but should take the form of a constructive collaboration, increasing the chances of reaching each individual goal.

A framework to assess the value of subgroup analyses when the overall treatment effect is significant

Although subgroup analysis has been developed and widely used for many years, it is still not clear whether we should perform and how to perform such subgroup analyses when the overall treatment effect is significant. In this paper, we develop a framework to assess and compute the long-term impact of different strategies to perform subgroup analysis. We propose two performance measures: the average gain for patients in the future (E) and the probability of recommending a change to a worse treatment at individual patient level (P). Five families of decision rules are applied under different assumptions for the individual treatment effect (TE) variation. Three distributions reflecting optimistic, moderate, and pessimistic scenarios are assumed for true treatment effects across studies. This framework allows us to compare subgroup analyses decision rules, and we demonstrate through simulation studies that there are decision rules for subgroup analysis which can decrease P and increase E simultaneously compared to the situation of no subgroup analysis. These rules are much more liberal than the usual superiority testing. The latter typically implies a dramatic decrease in E.

Janus kinase-1 and Janus kinase-2 inhibitors for treating myelofibrosis

BACKGROUND

Myelofibrosis is a bone marrow disorder characterized by excessive production of reticulin and collagen fiber deposition caused by hematological and non-hematological disorders. The prognosis of myelofibrosis is poor and treatment is mainly palliative. Janus kinase inhibitors are a novel strategy to treat people with myelofibrosis.

OBJECTIVES

To determine the clinical benefits and harms of Janus kinase-1 and Janus kinase-2 inhibitors for treating myelofibrosis secondary to hematological or non-hematological conditions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library 2014, Issue 11), Ovid MEDLINE (from 1946 to 13 November 2014), EMBASE (from 1980 to 12 January 2013), and LILACS (from 1982 to 20 November 2014). We searched WHO International Clinical Trials Registry Platform and The metaRegister of Controlled Trials. We also searched for conference proceedings of the American Society of Hematology (from 2009 to October 2013), European Hematology Association (from 2009 to October 2013), American Society of Clinical Oncology (from 2009 to October 2013), and European Society of Medical Oncology (from 2009 to October 2013). We included searches in FDA, European Medicines Agency, and Epistemonikos. We handsearched the references of all identified included trials, and relevant review articles. We did not apply any language restrictions. Two review authors independently screened search results.

SELECTION CRITERIA

We included randomized clinical trials comparing Janus kinase-1 and Janus kinase-2 inhibitors with placebo or other treatments. Both previously treated and treatment naive patients were included.

DATA COLLECTION AND ANALYSIS

We used the hazard ratio (HR) and 95% confidence interval (95% CI) for overall survival, progression-free survival and leukemia-free survival, risk ratio (RR) and 95% CI for reduction in spleen size and adverse events binary data, and standardized mean differences (SMD) and 95% CI for continuous data (health-related quality of life). Two review authors independently extracted data and assessed the risk of bias of included trials. Primary outcomes were overall survival, progression-free survival and adverse events.

MAIN RESULTS

We included two trials involving 528 participants, comparing ruxolitinib with placebo or best available therapy (BAT). As the two included trials had different comparators we did not pool the data. The confidence in the results estimates of these trials was low due to the bias in their design, and their limited sample sizes that resulted in imprecise results.There is low quality evidence for the effect of ruxolitinib on survival when compared with placebo at 51 weeks of follow-up (HR 0.51, 95% CI 0.27 to 0.98) and compared with BAT at 48 weeks of follow-up (HR 0.70, 95% CI 0.20 to 2.47). Similarly there was very low quality evidence for the effect of ruxolitinib on progression free survival compared with BAT (HR 0.81, 95% CI 0.47 to 1.39).There is low quality evidence for the effect of ruxolitinib in terms of quality of life. Compared with placebo, the drug achieved a greater proportion of patients with a significant reduction of symptom scores (RR 8.82, 95% CI 4.40 to 17.69), and treated patients with ruxolitinib obtained greater MFSAF scores at the end of follow-up (MD -87.90, 95% CI -139.58 to -36.22). An additional trial showed significant differences in EORTC QLQ-C30 scores when compared ruxolitinib with best available therapy (MD 7.60, 95% CI 0.35 to 14.85).The effect of ruxolitinib on reduction in the spleen size of participants compared with placebo or BAT was uncertain (versus placebo: RR 64.58, 95% CI 9.08 to 459.56, low quality evidence; versus BAT: RR 41.78, 95% CI 2.61 to 669.75, low quality evidence).There is low quality evidence for the effect of the drug compared with placebo on anemia (RR 2.35, 95% CI 1.62 to 3.41), neutropenia (RR 3.57, 95% CI 1.02 to 12.55) and thrombocytopenia (RR 9.74, 95% CI 2.32 to 40.96). Ruxolitinib did not result in differences versus BAT in the risk of anemia (RR 1.35, 95% CI 0.91 to 1.99, low quality evidence) or thrombocytopenia (RR 1.20; 95% CI 0.44 to 3.28, low quality evidence). The risk of non-hematologic grade 3 or 4 adverse events (including fatigue, arthralgia, nausea, diarrhea, extremity pain and pyrexia) was similar when ruxolitinib was compared with placebo or BAT. The rate of neutropenia comparing ruxolitinib with standard medical treatment was not reported by the trial.

AUTHORS' CONCLUSIONS

Currently, there is insufficient evidence to allow any conclusions regarding the efficacy and safety of ruxolitinib for treating myelofibrosis. The findings of this Cochrane review should be interpreted with caution as they are based on trials sponsored by industry, and include a small number of patients. Unless powered randomized clinical trials provide strong evidence of a treatment effect, and the trade-off between potential benefits and harms is established, clinicians should be cautious when administering ruxolitinib for treating patients with myelofibrosis.

Benchmarks for detecting 'breakthroughs' in clinical trials: empirical assessment of the probability of large treatment effects using kernel density estimation

OBJECTIVE

To understand how often 'breakthroughs,' that is, treatments that significantly improve health outcomes, can be developed.

DESIGN

We applied weighted adaptive kernel density estimation to construct the probability density function for observed treatment effects from five publicly funded cohorts and one privately funded group.

DATA SOURCES

820 trials involving 1064 comparisons and enrolling 331,004 patients were conducted by five publicly funded cooperative groups. 40 cancer trials involving 50 comparisons and enrolling a total of 19,889 patients were conducted by GlaxoSmithKline.

RESULTS

We calculated that the probability of detecting treatment with large effects is 10% (5-25%), and that the probability of detecting treatment with very large treatment effects is 2% (0.3-10%). Researchers themselves judged that they discovered a new, breakthrough intervention in 16% of trials.

CONCLUSIONS

We propose these figures as the benchmarks against which future development of 'breakthrough' treatments should be measured.

Angioplasty versus bare metal stenting for superficial femoral artery lesions

BACKGROUND

Lower limb peripheral arterial disease (PAD) is a common, important manifestation of systemic atherosclerosis. Stenoses or occlusions in the superficial femoral artery may result in intermittent claudication or even critical ischaemia, which may be treated by balloon angioplasty with or without stenting. This is the first update of a review published in 2009.

OBJECTIVES

The primary aim was to determine the effect of percutaneous transluminal angioplasty (PTA) compared with PTA with bare metal stenting for superficial femoral artery (SFA) stenoses on vessel patency in people with symptomatic (Rutherford categories1 to 6; Fontaine stages II to IV) lower limb peripheral vascular disease.In addition, we assessed the efficacy of PTA and stenting in improving quality of life, ankle brachial index and treadmill walking distance.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched August 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 6).

SELECTION CRITERIA

Randomised trials of angioplasty alone versus angioplasty with bare metal stenting for the treatment of superficial femoral artery stenoses.

DATA COLLECTION AND ANALYSIS

Two review authors (MC, CT) independently selected suitable trials, assessed trial quality and extracted data. Furthermore, these two review authors performed assessments of methodological quality and wrote the final manuscript. The third review author (ADM) cross-checked all stages of the review process.

MAIN RESULTS

We include three new studies in this update, making a total of 11 included trials with 1387 participants. The average age was 69 years and all trials included men and women. Participants were followed for up to two years. There was an improvement in primary duplex patency at six and 12 months in participants treated with PTA plus stent over lesions treated with PTA alone (six months: odds ratio (OR) 2.90, 95% confidence interval (CI) 1.17 to 7.18, P = 0.02, six studies, 578 participants; 12 months: OR 1.78, 95% CI 1.02 to 3.10, P = 0.04, nine studies, 858 participants). This was lost by 24 months (P = 0.06). There was a significant angiographic patency benefit at six months (OR 2.49, 95% CI 1.49 to 4.17, P = 0.0005, four studies, 329 participants) which was lost by 12 months (OR 1.30, 95% CI 0.84 to 2.00, P = 0.24, five studies, 384 participants). Ankle brachial index (ABI) and treadmill walking distance showed no improvement at 12 months (P = 0.49 and P = 0.57 respectively) between participants treated with PTA alone or PTA with stent insertion. Three trials (660 participants) reported quality of life, which showed no significant difference between participants treated with PTA alone or PTA with stent insertion at any time interval. Antiplatelet therapy protocols and inclusion criteria regarding affected arteries between trials showed marked heterogeneity.

AUTHORS' CONCLUSIONS

Although there was a short-term gain in primary patency there was no sustained benefit from primary stenting of lesions of the superficial femoral artery in addition to angioplasty. Future trials should focus on quality of life for claudication and limb salvage for critical ischaemia.

Description of the protocols for randomized controlled trials on cancer drugs conducted in Spain (1999-2003)

OBJECTIVE

To describe the characteristics of randomized controlled clinical trials (RCT) on cancer drugs conducted in Spain between 1999 and 2003 based on their protocols.

METHODS

We conducted an observational retrospective cohort study to identify the protocols of RCTs on cancer drugs authorized by the Agencia Española del Medicamento y Productos Sanitarios (AEMPS) (Spanish Agency for Medicines and Medical Devices) during 1999-2003. A descriptive analysis was completed and the association between variables based on the study setting and sponsorship were assessed.

RESULTS

We identified a total of 303 protocols, which included 176,835 potentially eligible patients. Three-quarter of the studies were internationally-based, 61.7% were phase III, and 76.2% were sponsored by pharmaceutical companies. The most frequently assessed outcomes were response rate (24.7%), overall survival (20.7%), and progression-free survival (14.5%). Of all protocols, 10.6% intended to include more than 1000 patients (mean: 2442, SD: 2724). Compared with their national counterparts, internationally-based studies were significantly larger (p<0.001) and were more likely to implement centralized randomization (p<0.001), blinding of the intervention (p<0.001), and survival as primary outcome (p<0.001). Additionally, most internationally-based studies were sponsored by pharmaceutical companies (p<0.01). In a high percentage of protocols, the available information was not explicit enough to assess the validity of each trial. Compared to other European countries, the proportion of Spanish cancer drugs protocols registered at www.clinicaltrials.gov (7%) was lower.

CONCLUSION

RCTs on cancer drugs conducted in Spain between 1999 and 2003 were more likely to be promoted by pharmaceutical companies rather than by non-profit national groups. The former were more often part of international studies, which generally had better methodological quality than national ones. There are some worldwide on-going initiatives that aim to increase the transparency and quality of future research.