Are experimental treatments for cancer in children superior to established treatments? Observational study of randomised controlled trials by the Children's Oncology Group

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.

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.

Using numerical modeling and simulation to assess the ethical burden in clinical trials and how it relates to the proportion of responders in a trial sample

In order to propose a more precise definition and explore how to reduce ethical losses in randomized controlled clinical trials (RCTs), we set out to identify trial participants who do not contribute to demonstrating that the treatment in the experimental arm is superior to that in the control arm. RCTs emerged mid-last century as the gold standard for assessing efficacy, becoming the cornerstone of the value of new therapies, yet their ethical grounds are a matter of debate. We introduce the concept of unnecessary participants in RCTs, the sum of non-informative participants and non-responders. The non-informative participants are considered not informative with respect to the efficacy measured in the trial in contrast to responders who carry all the information required to conclude on the treatment's efficacy. The non-responders present the event whether or not they are treated with the experimental treatment. The unnecessary participants carry the burden of having to participate in a clinical trial without benefiting from it, which might include experiencing side effects. Thus, these unnecessary participants carry the ethical loss that is inherent to the RCT methodology. On the contrary, responders to the experimental treatment bear its entire efficacy in the RCT. Starting from the proportions observed in a real placebo-controlled trial from the literature, we carried out simulations of RCTs progressively increasing the proportion of responders up to 100%. We show that the number of unnecessary participants decreases steadily until the RCT's ethical loss reaches a minimum. In parallel, the trial sample size decreases (presumably its cost as well), although the trial's statistical power increases as shown by the increase of the chi-square comparing the event rates between the two arms. Thus, we expect that increasing the proportion of responders in RCTs would contribute to making them more ethically acceptable, with less false negative outcomes.

Are survival and mortality rates associated with recruitment to clinical trials in teenage and young adult patients with acute lymphoblastic leukaemia? A retrospective observational analysis in England

OBJECTIVE

Participation rates in clinical trials are low in teenagers and young adults (TYA) with cancer. Whilst the importance of clinical trials in informing best practice is well established, data regarding individual patient benefit are scarce. We have investigated the association between overall survival and trial recruitment in TYA patients with acute lymphoblastic leukaemia (ALL).

DESIGN

Retrospective.

SETTING

National (England) TYA patients treated for ALL.

PARTICIPANTS

511 patients aged 15-24 years diagnosed with ALL between 2004 and 2010 inclusive, of whom 239 (46.7%) participated in the UKALL2003 trial.

OUTCOME MEASURES

Patients were identified using National Clinical Trial (UKALL2003) and Cancer Registry (National Cancer Data Repository, English National Cancer Online Registration Environment) Databases. Relative survival rates were calculated for trial and non-trial patients and observed differences were modelled using a multiple regression approach. The numbers and percentages of deaths in those patients included in the survival analysis were determined for each 3-month period, p values were calculated using the two-tailed z-test for difference between proportions and 95% CIs for percentage deaths were derived using the binomial distribution based on the Wilson Score method.

RESULTS

Patients treated on the trial had a 17.9% better 2-year survival (85.4% vs 67.5%, p<0.001) and 8.9% better 1-year survival (90.8% vs 81.9%, p=0.004) than those not on the trial. 35 (14.6%) patients recruited to the trial died in the 2 years following diagnosis compared with 86 (32.6%) of those not recruited (p<0.001).

CONCLUSIONS

TYA patients recruited to the clinical trial UKALL 2003 in England had a lower risk of mortality and a higher overall survival than contemporaneous non-trial patients. These data underline the potential for individual patient benefit in participating in a clinical trial and the importance of international efforts to increase trial participation in the TYA age group.

TRIAL REGISTRATION NUMBER

ISRCTN07355119.

A qualitative study of decision-making on Phase III randomized clinical trial participation in paediatric oncology: Adolescents' and parents' perspectives and preferences

AIM

To explore parents' and adolescents' motives for accepting/declining participation in the ALL2008 trials and adolescents' involvement in the decision-making process.

BACKGROUND

Children and adolescents with acute lymphoblastic leukaemia treated on the Nordic Society of Paediatric Haematology and Oncology ALL2008 protocol were eligible for two randomizations testing 6-mercaptopurine treatment intensifications to improve efficacy and Asparaginase de-escalation to reduce toxicity. We recently reported that while adolescents favoured treatment reduction, parents of young children favoured treatment intensification.

DESIGN

A qualitative, exploratory study.

METHODS

A maximum variation sampling strategy was used. Five adolescents aged 12-17 years, six parents of adolescents and five parents of children aged 1-12 years were interviewed in the period March-May 2015. Data were analysed using content analysis.

FINDINGS

Adolescents and parents emphasized the importance of adolescents' active participation in decisions regarding enrolment into clinical trials. A majority of adolescents were either final or collaborative decision-makers. Parents stated that in case of disagreement, they would overrule the adolescents' decision. There were no differences between motivations of preferences held by parents of children or adolescents, respectively. Decisions were based on subjective values attributed to cure contra toxicity and individual preferences for either standard or experimental treatment. The possibility of a negative outcome induced fear of decisional regret and distress by the parents, yet they invested considerable trust in the physician's expertise.

CONCLUSION

Our findings highlight the importance of adolescents' active involvement in consent conferences. Research on management of disagreements between adolescents and parents in trial decisions is needed.

Access to clinical trials for adolescents with soft tissue sarcomas: Enrollment in European pediatric Soft tissue sarcoma Study Group (EpSSG) protocols

BACKGROUND

Adolescents with cancer are enrolled in clinical trials at far lower rates than children. This report compares the number of adolescents (15-19-year-olds) and children (0-14-year-olds) enrolled in the protocols of the European pediatric Soft tissue sarcoma Study Group (EpSSG) with the number of cases expected to occur.

METHODS

The observed-to-expected (O/E) ratio was detected in the EpSSG countries contributing most of the cases, that is, Italy, France, Spain, the Netherlands, United Kingdom, and Ireland. The observed cases included patients enrolled in any of the EpSSG protocols from October 2008 to October 2015, when all EpSSG protocols were open in these countries. The number of expected cases was calculated from the incidence rates estimated throughout the RARECAREnet database in the countries' population-based cancer registries.

RESULTS

In the countries considered, 2,118 cases aged 0-19 years were enrolled in the EpSSG trials from 2008 to 2015: 82.8% were children and 17.2% were adolescents. The O/E ratio was 0.30 among patients 15-19 years old, as opposed to 0.64 for those 0-14 years old. The O/E ratio differed for the different subtypes: in adolescents, it was 0.64 and 0.18 for rhabdomyosarcoma (RMS) and non-rhabdomyosarcoma soft tissue sarcomas (NRSTS), respectively; in children, it was 0.77 and 0.50, respectively. The O/E ratios differed across the countries considered.

CONCLUSIONS

Adolescents were less well represented than children on the EpSSG protocols, with better enrolment for RMS than for NRSTS for all age groups.

Parents' and Adolescents' Preferences for Intensified or Reduced Treatment in Randomized Lymphoblastic Leukemia Trials

BACKGROUND

When offered participation in clinical trials, families of children with cancer face a delicate balance between cure and toxicity. Since parents and children may perceive this balance differently, this paper explores whether adolescent patients have different enrollment patterns compared to younger children in trials with different toxicity profiles.

PROCEDURE

Age-dependent participation rates in three consecutive, randomized childhood leukemia trials conducted by the Nordic Society of Paediatric Haematology and Oncology were evaluated. The ALL2000 dexamethasone/vincristine (Dx/VCR) trial tested treatment intensifications to improve cure, and the back-to-back ALL2008 6-mercaptopurine (6MP) and ALL2008 PEG-asparaginase (ASP) trials tested treatment intensifications (6MP) and toxicity reduction without compromising survival (ASP). Patient randomization and toxicity data were prospectively registered by the treating physicians.

RESULTS

Parents of young children favored treatment intensifications (Dx/VCR: 12% refusal; 6MP: 14%; ASP: 21%), whereas parents of adolescents favored treatment reductions (Dx/VCR: 52% refusal; 6MP: 30%; ASP: 8%). Adolescents were more likely to refuse intensification trials than young children (adjusted ORs 6.3; P < 0.01 [Dx/VCR] and 2.1; P = 0.04 [6MP]). Adolescents were less likely to refuse the ASP trial, with varying effect size depending on the length of the preceding consolidation treatment (adjusted OR for median consolidation length 0.15; P = 0.01). Younger children participated more frequently in only 6MP than in only ASP (14% vs. 5%), and adolescents vice versa (2% vs. 17%; P = 0.001).

CONCLUSIONS

Parents' and adolescents' divergent inclinations toward intensified or reduced therapy emphasize the necessity of actively involving adolescents in the informed consent process, which should also address motives for trial participation.

The Rise of Consumer Health Wearables: Promises and Barriers

Lukasz Piwek and colleagues consider whether wearable technology can become a valuable asset for health care.

Case-linked analysis of clinical trial enrollment among adolescents and young adults at a National Cancer Institute-designated comprehensive cancer center

BACKGROUND

Poor accrual to cancer clinical trials may contribute to the lower improvement in survival observed for adolescents and young adults (AYAs) (those aged 15-39 years) with cancer. This has been difficult to quantify without reliable mechanisms to link incident cases with study enrollments. Using unique resources available at their National Cancer Institute-designated comprehensive cancer center, the authors compared the percentage of AYAs, children, and older adults enrolled onto cancer clinical trials and determined predictors of enrollment.

METHODS

Patients diagnosed with cancer from January 2008 through December 2012 at 1 pediatric and 2 adult University of Southern California hospitals were identified through the California Cancer Registry and individually linked to institutional trial enrollment databases. The availability of clinical trials was assessed.

RESULTS

Across the center, the enrollment percentage for AYAs (6%) was equal to that of older adults (6%), but was less than that for children (22%) (P < .01). Within the children's hospital, the AYA enrollment percentage was also less than that for children (15% vs 23%, respectively; P<.01). On multivariate analysis, diagnosis and site of care were found to be predictive of AYA enrollment onto therapeutic and nontherapeutic studies. Hispanic and Asian/Pacific Islander individuals were more likely to enroll onto nontherapeutic studies compared with non-Hispanic whites, but no racial/ethnic difference was observed for therapeutic studies.

CONCLUSIONS

In the current study, the percentages of AYAs and older adults enrolled onto therapeutic trials were low but similar. Diagnosis, site of care, and race/ethnicity appear to be predictive of enrollment. Prospective mechanisms must be instituted to capture reasons for nonenrollment of AYAs and develop corrective interventions.

Control treatments in biologics trials of rheumatoid arthritis were often not deemed acceptable in the context of care

OBJECTIVES

Control treatments in randomized controlled trials (RCTs) should not deliberately disadvantage patients. The objectives of the study were to compare (1) willingness to include vs. (2) willingness to prescribe control treatment among physicians randomized to assess, respectively, either (1) enrollment in a trial or (2) appropriateness of control treatment in a care context for the same fictional patient.

STUDY DESIGN AND SETTING

Physicians were authors of articles about rheumatoid arthritis (RA), involved in RA patient care, and used to enrolling patients in trials. The outcomes were willingness to give control treatment: trial enrollment or control-treatment appropriateness in care context. We derived three case vignettes of fictional standard eligible patients for each of 30 RCTs assessing biologics in RA. Physicians were randomly allocated to the "trial" or "care" arm. For each of the 90 fictional patients, physicians assigned to the trial arm were asked if they would enroll the patient in the RCT the patient was derived from. For the same 90 fictional patients, physicians assigned to the care arm were asked if the control treatment of the RCT was appropriate in a context of usual care.

RESULTS

Of the 1,779 physicians invited to participate, 151 were randomized. Half of the fictional patients {41/90; 45% [95% confidence interval (CI): 37%, 53%]} would be enrolled in the RCT although the control-arm treatment of the RCT was not considered appropriate for them in the context of care. This rate differed by type of comparator [55% for non-head-to-head RCTs vs. 6% for head-to-head RCTs; adjusted odds ratio (aOR), 23.9 (95% CI: 5.5, 92.7)] and duration of trial control treatment [56% for ≤24 weeks and 15% for >24 weeks; aOR, 10.7 (95% CI: 2.8, 63.9)] but not patient RA activity [aOR, 2.5 (95% CI: 1.0, 6.6)]. The limitation of this study was that physicians gave their opinion on fictional patients with only RA.

CONCLUSIONS

Control treatments in RCTs of biologics in RA are often deemed not acceptable in the context of usual care, especially those for non-head-to-head RCTs. These findings raise ethical concerns and challenge the choice of the comparator in RCTs.

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.

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.

Attitudes Toward Cancer Clinical Trial Participation in Young Adults with a History of Cancer and a Healthy College Student Sample: A Preliminary Investigation

Purpose: Adolescents and young adults (AYAs) aged 15-39 at diagnosis have very low cancer clinical trial accrual rates. To date, no studies have examined attitudes toward clinical trial participation in this age range to determine if certain individuals are less likely to enroll if offered participation. The current study assessed attitudes toward participation using the Cancer Treatment Subscale of the Attitudes toward Cancer Trials Scales. Methods: Data were collected from a sample of leukemia and lymphoma survivors (n=99) and a healthy college student sample (n=397). Following a principal components analysis, two subscales-Personal Barriers/Safety and Personal Benefits-were retained for analysis. Results: In the cancer survivor group, only 14 (13.3%) reported being offered participation in a cancer clinical trial, and only 8 of those 14 (7.6% of survivors) participated. Responses from leukemia and lymphoma survivors revealed no significant relationships between age, gender, race/ethnicity, clinical trial participation, insurance status, or social class with Personal Benefits or Personal Barriers/Safety. Healthy college females had more negative Personal Barriers/Safety attitudes compared to males after adjusting for race/ethnicity and social class (p=0.01), but no associations were present when examining Personal Benefits as an outcome. Conclusion: This preliminary investigation suggests that drivers of attitudes toward clinical trial participation in AYAs are not well understood and may impact cancer trial participation. Future work should focus on defining attitudes toward cancer clinical trials in the AYA population and developing interventions to increase awareness, knowledge, and positive attitudes toward participating in cancer research.

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

OBJECTIVE

To assess if commercially sponsored trials are associated with higher success rates than publicly-sponsored trials.

STUDY DESIGN AND SETTINGS

We undertook a systematic review of all consecutive, published and unpublished phase III cancer randomized controlled trials (RCTs) conducted by GlaxoSmithKline (GSK) and the NCIC Clinical Trials Group (CTG). We included all phase III cancer RCTs assessing treatment superiority from 1980 to 2010. Three metrics were assessed to determine treatment successes: (1) the proportion of statistically significant trials favouring the experimental treatment, (2) the proportion of the trials in which new treatments were considered superior according to the investigators, and (3) quantitative synthesis of data for primary outcomes as defined in each trial.

RESULTS

GSK conducted 40 cancer RCTs accruing 19,889 patients and CTG conducted 77 trials enrolling 33,260 patients. 42% (99%CI 24 to 60) of the results were statistically significant favouring experimental treatments in GSK compared to 25% (99%CI 13 to 37) in the CTG cohort (RR = 1.68; p = 0.04). Investigators concluded that new treatments were superior to standard treatments in 80% of GSK compared to 44% of CTG trials (RR = 1.81; p<0.001). Meta-analysis of the primary outcome indicated larger effects in GSK trials (odds ratio = 0.61 [99%CI 0.47-0.78] compared to 0.86 [0.74-1.00]; p = 0.003). However, testing for the effect of treatment over time indicated that treatment success has become comparable in the last decade.

CONCLUSIONS

While overall industry sponsorship is associated with higher success rates than publicly-sponsored trials, the difference seems to have disappeared over time.

Unblinding following trial participation: qualitative study of participants' perspectives

BACKGROUND

The implications of offering unblinding to trial participants to treatment arm after trial completion have been little explored.

PURPOSE

We sought to explore trial participants' perspectives on whether they would like to be unblinded as to the treatment arm to which they were allocated following involvement in a large randomised controlled trial (RCT).

METHODS

We conducted semi-structured interviews with 38 women who had participated in a trial during suspected preterm labour and had received the results of a long-term follow-up study that identified adverse outcomes for children in some of the treatment groups. Participants were sampled purposively. Analysis was based on the constant comparative method.

RESULTS

Most women reported that they wanted to know the treatment arm to which they had been allocated. While the primary motive for some was curiosity, many others wanted to know as part of an attempt to understand or explain their child's current health problems. These women were motivated by a search for a coherent causal narrative, even though unblinding was unlikely to be able to meet their aspirations. Some participants identified potential disadvantages in discovering their treatment allocation, including feeling responsible for their child's health status, and some women were very clear that they did not want to know their treatment group.

LIMITATIONS

A purposive sample was used and the extent to which it represents the views of all participants in the study is not established.

CONCLUSIONS

Important challenges arise in offering to unblind trial participants, whatever the trial results. Participants may need help and support to understand the limitations of the knowledge they gain through being unblinded and to decide whether they wish to know to which treatment arm they were allocated.

New treatments compared to established treatments in randomized trials

BACKGROUND

The proportion of proposed new treatments that are 'successful' is of ethical, scientific, and public importance. We investigated how often new, experimental treatments evaluated in randomized controlled trials (RCTs) are superior to established treatments.

OBJECTIVES

Our main question was: "On average how often are new treatments more effective, equally effective or less effective than established treatments?" Additionally, we wanted to explain the observed results, i.e. whether the observed distribution of outcomes is consistent with the 'uncertainty requirement' for enrollment in RCTs. We also investigated the effect of choice of comparator (active versus no treatment/placebo) on the observed results.

SEARCH METHODS

We searched the Cochrane Methodology Register (CMR) 2010, Issue 1 in The Cochrane Library (searched 31 March 2010); MEDLINE Ovid 1950 to March Week 2 2010 (searched 24 March 2010); and EMBASE Ovid 1980 to 2010 Week 11 (searched 24 March 2010).

SELECTION CRITERIA

Cohorts of studies were eligible for the analysis if they met all of the following criteria: (i) consecutive series of RCTs, (ii) registered at or before study onset, and (iii) compared new against established treatments in humans.

DATA COLLECTION AND ANALYSIS

RCTs from four cohorts of RCTs met all inclusion criteria and provided data from 743 RCTs involving 297,744 patients. All four cohorts consisted of publicly funded trials. Two cohorts involved evaluations of new treatments in cancer, one in neurological disorders, and one for mixed types of diseases. We employed kernel density estimation, meta-analysis and meta-regression to assess the probability of new treatments being superior to established treatments in their effect on primary outcomes and overall survival.

MAIN RESULTS

The distribution of effects seen was generally symmetrical in the size of difference between new versus established treatments. Meta-analytic pooling indicated that, on average, new treatments were slightly more favorable both in terms of their effect on reducing the primary outcomes (hazard ratio (HR)/odds ratio (OR) 0.91, 99% confidence interval (CI) 0.88 to 0.95) and improving overall survival (HR 0.95, 99% CI 0.92 to 0.98). No heterogeneity was observed in the analysis based on primary outcomes or overall survival (I(2) = 0%). Kernel density analysis was consistent with the meta-analysis, but showed a fairly symmetrical distribution of new versus established treatments indicating unpredictability in the results. This was consistent with the interpretation that new treatments are only slightly superior to established treatments when tested in RCTs. Additionally, meta-regression demonstrated that results have remained stable over time and that the success rate of new treatments has not changed over the last half century of clinical trials. The results were not significantly affected by the choice of comparator (active versus placebo/no therapy).

AUTHORS' CONCLUSIONS

Society can expect that slightly more than half of new experimental treatments will prove to be better than established treatments when tested in RCTs, but few will be substantially better. This is an important finding for patients (as they contemplate participation in RCTs), researchers (as they plan design of the new trials), and funders (as they assess the 'return on investment'). Although we provide the current best evidence on the question of expected 'success rate' of new versus established treatments consistent with a priori theoretical predictions reflective of 'uncertainty or equipoise hypothesis', it should be noted that our sample represents less than 1% of all available randomized trials; therefore, one should exercise the appropriate caution in interpretation of our findings. In addition, our conclusion applies to publicly funded trials only, as we did not include studies funded by commercial sponsors in our analysis.

Flexible trial design in practice - stopping arms for lack-of-benefit and adding research arms mid-trial in STAMPEDE: a multi-arm multi-stage randomized controlled trial

BACKGROUND

Systemic Therapy for Advanced or Metastatic Prostate cancer: Evaluation of Drug Efficacy (STAMPEDE) is a randomized controlled trial that follows a novel multi-arm, multi-stage (MAMS) design. We describe methodological and practical issues arising with (1) stopping recruitment to research arms following a pre-planned intermediate analysis and (2) adding a new research arm during the trial.

METHODS

STAMPEDE recruits men who have locally advanced or metastatic prostate cancer who are starting standard long-term hormone therapy. Originally there were five research and one control arms, each undergoing a pilot stage (focus: safety, feasibility), three intermediate 'activity' stages (focus: failure-free survival), and a final 'efficacy' stage (focus: overall survival). Lack-of-sufficient-activity guidelines support the pairwise interim comparisons of each research arm against the control arm; these pre-defined activity cut-off becomes increasingly stringent over the stages. Accrual of further patients continues to the control arm and to those research arms showing activity and an acceptable safety profile. The design facilitates adding new research arms should sufficiently interesting agents emerge. These new arms are compared only to contemporaneously recruited control arm patients using the same intermediate guidelines in a time-delayed manner. The addition of new research arms is subject to adequate recruitment rates to support the overall trial aims.

RESULTS

(1) Stopping Existing Therapy: After the second intermediate activity analysis, recruitment was discontinued to two research arms for lack-of-sufficient activity. Detailed preparations meant that changes were implemented swiftly at 100 international centers and recruitment continued seamlessly into Activity Stage III with 3 remaining research arms and the control arm. Further regulatory and ethical approvals were not required because this was already included in the initial trial design.(2) Adding New Therapy: An application to add a new research arm was approved by the funder, (who also organized peer review), industrial partner and regulatory and ethical bodies. This was all done in advance of any decision to stop current therapies.

CONCLUSIONS

The STAMPEDE experience shows that recruitment to a MAMS trial and mid-flow changes its design are achievable with good planning. This benefits patients and the scientific community as research treatments are evaluated in a more efficient and cost-effective manner.

TRIAL REGISTRATION

ISRCTN78818544, NCT00268476. First patient into trial: 17 October 2005. First patient into abiraterone comparison: 15 November 2011.

Perceived information gain from randomized trials correlates with publication in high-impact factor journals

OBJECTIVE

To examine whether perceived information gain (IG) drives the publication of randomized trials in high-impact factor (IF) journals.

STUDY DESIGN AND SETTING

We estimated IG as the Kullback-Leibler divergence, quantifying how much a new finding changes established knowledge. We used 67 meta-analyses (964 randomized trials) that include one or more trials from any of the three highest IF general medical journals (NEJM, JAMA, and Lancet). We calculated IG for the presence of a non-null effect (IG(1)) and IG for the effect size magnitude (IG(2)).

RESULTS

Across meta-analyses, the summary correlation coefficient of IF was 0.23 (95% confidence interval [CI]: 0.14, 0.31) for IG(1) and 0.35 (95% CI: 0.25, 0.46) for IG(2). IF also correlated with the P-value of the results (r=0.18), order of publication (r=-0.13), and number of events in the trial (r=0.36). Multivariate regression including IG, order of publication, P-value, and the number of events showed that IG is an independent correlate of IF. IG(2) explained a substantially larger proportion of the variance in IF than IG(1).

CONCLUSION

Publication in journals with high IF is driven by how extensively the results of a study change prior perceptions of the evidence, independently of the statistical significance and size of the study.

Ancillary care in public health intervention research in low-resource settings: researchers' practices and decision-making

Little is known about researchers' practices regarding the provision of ancillary care (AC) in public health intervention studies they have conducted and the factors that influence their decisions about whether to provide ancillary care in low-resource settings. We conducted 52 in-person in-depth interviews with public health researchers. Data analysis was iterative and led to the identification of themes and patterns among themes. We found that researchers who conduct their research in the community setting are more likely to identify and plan for the AC needs of potential research subjects before a study begins, whereas those affiliated with a permanent facility are more likely to deliver AC to research subjects on an ad hoc basis. Our findings suggest that on the whole, at least for public health intervention research in low-resource settings, researchers conducting research in the community setting confront more complex ethical and operational challenges in their decision-making about AC than do researchers conducting facility-based studies.

Ethical issues at the interface of clinical care and research practice in pediatric oncology: a narrative review of parents' and physicians' experiences

BACKGROUND

Pediatric oncology has a strong research culture. Most pediatric oncologists are investigators, involved in clinical care as well as research. As a result, a remarkable proportion of children with cancer enrolls in a trial during treatment. This paper discusses the ethical consequences of the unprecedented integration of research and care in pediatric oncology from the perspective of parents and physicians.

METHODOLOGY

An empirical ethical approach, combining (1) a narrative review of (primarily) qualitative studies on parents' and physicians' experiences of the pediatric oncology research practice, and (2) comparison of these experiences with existing theoretical ethical concepts about (pediatric) research. The use of empirical evidence enriches these concepts by taking into account the peculiarities that ethical challenges pose in practice.

RESULTS

Analysis of the 22 studies reviewed revealed that the integration of research and care has consequences for the informed consent process, the promotion of the child's best interests, and the role of the physician (doctor vs. scientist). True consent to research is difficult to achieve due to the complexity of research protocols, emotional stress and parents' dependency on their child's physician. Parents' role is to promote their child's best interests, also when they are asked to consider enrolling their child in a trial. Parents are almost never in equipoise on trial participation, which leaves them with the agonizing situation of wanting to do what is best for their child, while being fearful of making the wrong decision. Furthermore, a therapeutic misconception endangers correct assessment of participation, making parents inaccurately attribute therapeutic intent to research procedures. Physicians prefer the perspective of a therapist over a researcher. Consequently they may truly believe that in the research setting they promote the child's best interests, which maintains the existence of a therapeutic misconception between them and parents.

CONCLUSION

Due to the integration of research and care, their different ethical perspectives become intertwined in the daily practice of pediatric oncology. Increasing awareness of what this means for the communication between parents and physicians is essential. Future research should focus on efforts that overcome the problems that the synchronicity of research and care evokes.

Optimism bias leads to inconclusive results-an empirical study

OBJECTIVE

Optimism bias refers to unwarranted belief in the efficacy of new therapies. We assessed the impact of optimism bias on a proportion of trials that did not answer their research question successfully and explored whether poor accrual or optimism bias is responsible for inconclusive results.

STUDY DESIGN

Systematic review.

SETTING

Retrospective analysis of a consecutive-series phase III randomized controlled trials (RCTs) performed under the aegis of National Cancer Institute Cooperative groups.

RESULTS

Three hundred fifty-nine trials (374 comparisons) enrolling 150,232 patients were analyzed. Seventy percent (262 of 374) of the trials generated conclusive results according to the statistical criteria. Investigators made definitive statements related to the treatment preference in 73% (273 of 374) of studies. Investigators' judgments and statistical inferences were concordant in 75% (279 of 374) of trials. Investigators consistently overestimated their expected treatment effects but to a significantly larger extent for inconclusive trials. The median ratio of expected and observed hazard ratio or odds ratio was 1.34 (range: 0.19-15.40) in conclusive trials compared with 1.86 (range: 1.09-12.00) in inconclusive studies (P<0.0001). Only 17% of the trials had treatment effects that matched original researchers' expectations.

CONCLUSION

Formal statistical inference is sufficient to answer the research question in 75% of RCTs. The answers to the other 25% depend mostly on subjective judgments, which at times are in conflict with statistical inference. Optimism bias significantly contributes to inconclusive results.

Treatment success in pragmatic randomised controlled trials: a review of trials funded by the UK Health Technology Assessment programme

BACKGROUND

Previous research reviewed treatment success and whether the collective uncertainty principle is met in RCTs in the US National Cancer Institute portfolio. This paper classifies clinical trials funded by the UK HTA programme by results using the method applied to the US Cancer Institute trials, and compares the two portfolios.

METHODS

Data on all completed randomised controlled trials funded by the HTA programme 1993-2008 were extracted. Each trial's primary results was classified into six categories; 1) statistically significant in favour of the new treatment, 2) statistically significant in favour of the control treatment 3) true negative, 4) truly inconclusive, 5) inconclusive in favour of new treatment or 6) inconclusive in favour of control treatment. Trials were classified by comparing the 95% confidence interval for the difference in primary outcome to the difference specified in the sample size calculation. The results were compared with Djulbegovic's analysis of NCI trials.

RESULTS

Data from 51 superiority trials were included, involving over 48,000 participants and a range of diseases and interventions. 85 primary comparisons were available because some trials had more than two randomised arms or had several primary outcomes. The new treatment had superior results (whether significant or not) in 61% of the comparisons (52/85 95% CI 49.9% to 71.6%). The results were conclusive in 46% of the comparisons (19% statistically significant in favour of the new treatment, 5% statistically significant in favour of the control and 22% true negative). The results were classified as truly inconclusive (i.e. failed to answer the question asked) for 24% of comparisons (20/85). HTA trials included fewer truly inconclusive and statistically significant results and more results rated as true negative than NCI trials.

CONCLUSIONS

The pattern of results in HTA trials is similar to that of the National Cancer Institute portfolio. Differences that existed were plausible given the differences in the types of trials -HTA trials are more pragmatic. The results indicate HTA trials are compatible with equipoise. This classification usefully summarises the results from clinical trials and enables comparisons of different portfolios of trials.

Statistically significant meta-analyses of clinical trials have modest credibility and inflated effects

OBJECTIVE

To assess whether nominally statistically significant effects in meta-analyses of clinical trials are true and whether their magnitude is inflated.

STUDY DESIGN AND SETTING

Data from the Cochrane Database of Systematic Reviews 2005 (issue 4) and 2010 (issue 1) were used. We considered meta-analyses with binary outcomes and four or more trials in 2005 with P<0.05 for the random-effects odds ratio (OR). We examined whether any of these meta-analyses had updated counterparts in 2010. We estimated the credibility (true-positive probability) under different prior assumptions and inflation in OR estimates in 2005.

RESULTS

Four hundred sixty-one meta-analyses in 2005 were eligible, and 80 had additional trials included by 2010. The effect sizes (ORs) were smaller in the updating data (2005-2010) than in the respective meta-analyses in 2005 (median 0.85-fold, interquartile range [IQR]: 0.66-1.06), even more prominently for meta-analyses with less than 300 events in 2005 (median 0.67-fold, IQR: 0.54-0.96). Mean credibility of the 461 meta-analyses in 2005 was 63-84% depending on the assumptions made. Credibility estimates changed >20% in 19-31 (24-39%) of the 80 updated meta-analyses.

CONCLUSIONS

Most meta-analyses with nominally significant results pertain to truly nonnull effects, but exceptions are not uncommon. The magnitude of observed effects, especially in meta-analyses with limited evidence, is often inflated.

Pediatric oncologists' attitudes towards involving adolescents in decision-making concerning research participation

BACKGROUND

Various regulations and guidelines stipulate the importance of involving adolescents in decision-making concerning research participation. Several studies have shown that in the context of pediatric oncology this involvement is difficult to achieve due to emotional stress, the complexity of research protocols and limited time. Still, up to 80% of adolescents with cancer enter onto a trial during their illness. The aim of this study was to determine clinicians' views and attitudes towards enrolling adolescents in research, considering the difficulties surrounding their involvement in decision-making.

METHODS

A qualitative multicenter study was performed, using in-depth semi-structured interviews on the informed consent process with 15 pediatric hemato-oncologists.

RESULTS

Four central themes emerged that characterize clinicians' attitudes towards involving adolescents in the decision-making process: (1) clinicians regard most adolescents as not capable of participating meaningfully in discussions regarding research; (2) clinicians do not always provide adolescents with all information; (3) proxy consent from parents is obtained and is deemed sufficient; (4) clinician-investigator integrity: clinicians judge research protocols as not being harmful and even in the best interest of the adolescent.

CONCLUSIONS

Clinicians justify not involving adolescents in research discussions by referring to best interest arguments (adolescents' incompetence, proxy consent, and investigator integrity), although this is not in line with legal regulations and ethical guidelines.

The paradox of equipoise: the principle that drives and limits therapeutic discoveries in clinical research

BACKGROUND

Progress in clinical medicine relies on the willingness of patients to take part in experimental clinical trials, particularly randomized controlled trials (RCTs). Before agreeing to enroll in clinical trials, patients require guarantees that they will not knowingly be harmed and will have the best possible chances of receiving the most favorable treatments. This guarantee is provided by the acknowledgment of uncertainty (equipoise), which removes ethical dilemmas and makes it easier for patients to enroll in clinical trials.

METHODS

Since the design of clinical trials is mostly affected by clinical equipoise, the "clinical equipoise hypothesis" has been postulated. If the uncertainty requirement holds, this means that investigators cannot predict what they are going to discover in any individual trial that they undertake. In some instances, new treatments will be superior to standard treatments, while in others, standard treatments will be superior to experimental treatments, and in still others, no difference will be detected between new and standard treatments. It is hypothesized that there must be a relationship between the overall pattern of treatment successes and the uncertainties that RCTs are designed to address.

RESULTS

An analysis of published trials shows that the results cannot be predicted at the level of individual trials. However, the results also indicate that the overall pattern of discovery of treatment success across a series of trials is predictable and is consistent with clinical equipoise hypothesis. The analysis shows that we can discover no more than 25% to 50% of successful treatments when they are tested in RCTs. The analysis also indicates that this discovery rate is optimal in helping to preserve the clinical trial system; a high discovery rate (eg, a 90% to 100% probability of success) is neither feasible nor desirable since under these circumstances, neither the patient nor the researcher has an interest in randomization. This in turn would halt the RCT system as we know it.

CONCLUSIONS

The "principle or law of clinical discovery" described herein predicts the efficiency of the current system of RCTs at generating discoveries of new treatments. The principle is derived from the requirement for uncertainty or equipoise as a precondition for RCTs, the precept that paradoxically drives discoveries of new treatments while limiting the proportion and rate of new therapeutic discoveries.

Childhood and adolescent cancer survival in the US by race and ethnicity for the diagnostic period 1975-1999

BACKGROUND

Survival trends provide a measure of improvement in detection and treatment over time. In the current study, updated childhood and adolescent cancer survival statistics are presented, overall and among demographic subgroups, including Hispanics, for whom to the authors' knowledge national rates have not been previously reported. These results extend those provided by the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program in their detail and interpretation.

METHODS

Survival trends of primary cancers in children and adolescents (ages birth to 19 years) were evaluated using SEER 9 data. Five-year and 10-year relative survival rates across 5-year (1975-1979, 1985-1989, and 1995-1999) and 10-year (1975-1984 and 1985-1994) cohorts were compared via Z-tests. Annual percent change (APC) in survival was computed via weighted least-squares regression. Rates in Hispanic children and adolescents were compared with those in non-Hispanic whites and blacks (SEER 13, 1995-1999).

RESULTS

Five-year survival rates increased significantly overall (1975-1979: 63% vs 1995-1999: 79%; P< .0001) and for nearly all histologic types examined; increases were greatest for ependymoma (+37%; P< .0001) and non-Hodgkin lymphoma (+34%; P< .0001). Hispanic children and adolescents had somewhat poorer 5-year rates than non-Hispanic whites overall (74% vs 81%; P< .0001) and for Ewing sarcoma, leukemia, central nervous system tumors, and melanoma. Ten-year rates also increased significantly overall (1975-1984: 61% vs 1985-1994: 72%; P< .0001) and for a majority of cancer types. The largest improvements were noted for acute lymphoblastic leukemia (+19%; P< .0001) and non-Hodgkin lymphoma (+19%; P< .0001).

CONCLUSIONS

Observed trends reinforce the need for resources devoted to advancing treatment modalities, reducing disparities among racial/ethnic groups and adolescents, and providing long-term care of survivors.

Speeding up the evaluation of new agents in cancer

Despite both the increase in basic biologic knowledge and the fact that many new agents have reached various stages of development during the last 10 years, the number of new treatments that have been approved for patients has not increased as expected. We propose the multi-arm, multi-stage trial design as a way to evaluate treatments faster and more efficiently than current standard trial designs. By using intermediate outcomes and testing a number of new agents (and combinations) simultaneously, the new design requires fewer patients. Three trials using this methodology are presented.

The challenges of clinical trials for adolescents and young adults with cancer

In the United States, Europe, and Australia, and probably all countries of the world, older adolescents and young adults with cancer are under-represented in clinical trials of therapies that could improve their outcome. Simultaneously, the survival and mortality rates in these patients have mirrored the clinical trial accrual pattern, with little improvement compared with younger and older patients. This suggests that the relative lack of participation of adolescent and young adult patients in clinical trials has lessened their chances for as good an outcome as that enjoyed by patients in other age groups. Thus, increased availability of and participation in clinical trials is of paramount important if the current deficits in outcome in young adults and older adolescents are to be eliminated. Regardless of whether there is a causal relationship, the impact of low clinical trial activity on furthering our scientific knowledge and management of cancer during adolescence and early adulthood is detrimental.

Treatment success in cancer: new cancer treatment successes identified in phase 3 randomized controlled trials conducted by the National Cancer Institute-sponsored cooperative oncology groups, 1955 to 2006

BACKGROUND

The evaluation of research output, such as estimation of the proportion of treatment successes, is of ethical, scientific, and public importance but has rarely been evaluated systematically. We assessed how often experimental cancer treatments that undergo testing in randomized clinical trials (RCTs) result in discovery of successful new interventions.

METHODS

We extracted data from all completed (published and unpublished) phase 3 RCTs conducted by the National Cancer Institute cooperative groups since their inception in 1955. Therapeutic successes were determined by (1) assessing the proportion of statistically significant trials favoring new or standard treatments, (2) determining the proportion of the trials in which new treatments were considered superior to standard treatments according to the original researchers, and (3) quantitatively synthesizing data for main clinical outcomes (overall and event-free survival).

RESULTS

Data from 624 trials (781 randomized comparisons) involving 216 451 patients were analyzed. In all, 30% of trials had statistically significant results, of which new interventions were superior to established treatments in 80% of trials. The original researchers judged that the risk-benefit profile favored new treatments in 41% of comparisons (316 of 766). Hazard ratios for overall and event-free survival, available for 614 comparisons, were 0.95 (99% confidence interval [CI], 0.93-0.98) and 0.90 (99% CI, 0.87- 0.93), respectively, slightly favoring new treatments. Breakthrough interventions were discovered in 15% of trials.

CONCLUSIONS

Approximately 25% to 50% of new cancer treatments that reach the stage of assessment in RCTs will prove successful. The pattern of successes has become more stable over time. The results are consistent with the hypothesis that the ethical principle of equipoise defines limits of discoverability in clinical research and ultimately drives therapeutic advances in clinical medicine.

Observational research, randomised trials, and two views of medical science

Two views exist of medical science, says the author, one emphasizing discovery and explanation, the other emphasizing evaluation of interventions.

Participation of adolescents with cancer in clinical trials

Adolescent patients with cancer reside in a "no-man's land" between the world of pediatric oncology and that of "adult" medical oncology. As compared to younger and older patients, adolescents and young adults are under-represented on clinical trials. This relative lack of participation in clinical protocols has been associated to a lack of progress in survival improvement over the last years. One of the main reasons for the deficit in protocol enrolment and the worse outcome of adolescents (when compared in particular to children) is the lack of awareness by the public, community and healthcare systems that cancer may occur in this age group. However, physicians--inadequately trained or reluctant to care for adolescents--have important responsibilities. Most 15- to 19-year-olds diagnosed with cancer are treated at adult facilities, although two-thirds to three-fourths of their cancers are typical of those that occur in the pediatric age range. The best choice may be to treat them according to their type of tumor, not according to their age: "pediatric" tumors treated by pediatric oncologists, "adult" tumors by adult medical oncologists, regardless of the patient's age. This solution, however, is probably appropriate for the tumor, but not necessarily for the patient. Adolescents are neither old children nor young adults, and are very complicated individuals, with unique socio-psychological problems and needs, that may be addressed only by dedicated professionals, adequately trained and supported. The ultimate challenge is the development of a new discipline, adolescent/teenage and young adult oncology, devoted to the care of these patients.

Randomized controlled trials of treatments for hematologic malignancies: study characteristics and outcomes

BACKGROUND

Although randomized controlled trials (RCTs) require a great deal of time, money, and effort, the majority of them have resulted in failure to verify a priori hypotheses. Therefore, the intention in the current study was to clarify the differential elements of studies with 'positive' and 'negative' outcomes.

METHODS

The authors performed a comprehensive search of RCT reports on treatments for hematologic malignancies published between 1995 and 2004, with 264 reports eventually identified. The expected rate and the observed rate for the primary endpoint were compared for 70 studies with all relevant information available.

RESULTS

Of all the superiority trials (n = 256), positive studies accounted for 33%. Most of the major study characteristics were not found to be associated with the study outcome except for the primary endpoint. Studies evaluating event-free survival were more likely to report positive results than were those evaluating overall survival (P = .061). For the experimental treatment arm, the mean difference between the expected and observed rates was -10.1% (standard deviation [SD], 10.1%) in the negative studies, which indicates a rate lower than expected, and was 1.3% (SD, 9.2%) in the positive studies (P < .0001). In contrast, no statistical significance was observed for the standard treatment arm because the mean difference was 6.3% (SD, 10.7%) for the negative studies and 3.0% (SD, 9.0%) for the positive studies (P = .1885). The journal impact factor was statistically significantly higher for the positive than for the negative reports (P < .0001).

CONCLUSIONS

Giving adequate consideration to the estimated effect of an experimental therapy may be critical when planning an RCT.

Treatment tolerance and efficacy in geriatric oncology: a systematic review of phase III randomized trials conducted by five National Cancer Institute-sponsored cooperative groups

PURPOSE

Elderly patients share the majority of the disease burden in cancer. Although 61% of new cancer cases occur among elderly, they comprise only 25% of the patients enrolled onto randomized clinical trials (RCTs). A systematic review to assess the accurate participation of elderly patients in RCTs has not been performed.

PATIENTS AND METHODS

We reviewed all consecutively completed phase III RCTs conducted by five National Cancer Institute-sponsored cooperative groups. Published papers and study protocols were used for data extraction. We used a cutoff age of 65 years to define elderly patients. For trials that did not exclusively enroll elderly, data were extracted on number of participants 65 years of age. Outcome between the innovative and the standard treatment was compared.

RESULTS

Of 345 studies, only one trial exclusively enrolled elderly patients (0.28%); 57% of the trials (n = 197) had no stratification by age, and 12% of the studies had a stratification age 65 years (n = 42). Overall survival in the trial exclusively enrolling elderly favored the newer treatments (hazard ratio [HR], 0.69; 95% CI, 0.47 to 1.02; P = .06). Additionally, in trials enrolling more than 40% of elderly, survival and event-free survival favored the innovative treatments (HR for survival, 0.91; 95% CI, 0.84 to 0.99; P = .03; HR for event-free survival, 0.85; 95% CI, 0.72 to 1.01; P = .07). Treatment-related mortality was similar in both the innovative and standard treatment groups (HR, 0.91; 95% CI, 0.47 to 1.78; P = .8).

CONCLUSION

Our data indicate that enrollment of elderly in experimental RCTs is not associated with increased harm to this patient population. Increased participation of elderly may help in finding new treatments that are clinically applicable specifically to this cohort of patients.