Is response rate relevant to the phase II trial design of targeted agents?

A Review of Perspectives on the Use of Randomization in Phase II Oncology Trials

Historically, phase II oncology trials assessed a treatment's efficacy by examining its tumor response rate in a single-arm trial. Then, approximately 25 years ago, certain statistical and pharmacological considerations ignited a debate around whether randomized designs should be used instead. Here, based on an extensive literature review, we review the arguments on either side of this debate. In particular, we describe the numerous factors that relate to the reliance of single-arm trials on historical control data and detail the trial scenarios in which there was general agreement on preferential utilization of single-arm or randomized design frameworks, such as the use of single-arm designs when investigating treatments for rare cancers. We then summarize the latest figures on phase II oncology trial design, contrasting current design choices against historical recommendations on best practice. Ultimately, we find several ways in which the design of recently completed phase II trials does not appear to align with said recommendations. For example, despite advice to the contrary, only 66.2% of the assessed trials that employed progression-free survival as a primary or coprimary outcome used a randomized comparative design. In addition, we identify that just 28.2% of the considered randomized comparative trials came to a positive conclusion as opposed to 72.7% of the single-arm trials. We conclude by describing a selection of important issues influencing contemporary design, framing this discourse in light of current trends in phase II, such as the increased use of biomarkers and recent interest in novel adaptive designs.

Reporting trends of outcome measures in phase II and phase III trials conducted in advanced-stage non-small-cell lung cancer

BACKGROUND

The methodology of conducting clinical trials in lung cancer has been challenged by the particular characteristics of new targeted agents. Thus, the choice of correct outcome measures and selection of best study designs are essential. We assessed the trends in reporting of outcome measures in phase II and phase III trials conducted in advanced non-small-cell lung cancer (NSCLC) patients.

METHODS

Data from September 2000 to September 2012 were extracted from the ClinicalTrials.gov database, and a descriptive-comparative analysis was performed to evaluate outcome-measures reporting for the two phases.

RESULTS

We identified 459 phase II and 128 phase III trials that met our inclusion criteria. The frequently reported primary outcomes in phase II trials were progression-free survival (PFS; 32%), response rate (RR; 21.4%), and safety and toxicity (adverse events [AEs]; 14.6%). In contrast, overall survival (OS; 60.9%) and PFS (26.6%) were frequently reported primary outcomes in phase III trials. AEs were reported as a secondary outcome measure in 50.1 and 64.8% of phase II and phase III trials, respectively. Improvement in quality of life was identified as a secondary outcome measure significantly more frequently in phase III than in phase II trials.

CONCLUSIONS

Our study identified recent trends in reports of outcome measures in advanced-stage NSCLC phase II and phase III trials. The outcomes of this study can be valuable for investigators with minimal or some experience in the field of oncology who are conducting clinical research.

Role of Biomarkers in the Clinical Management of Glioblastomas: What are the Barriers and How Can We Overcome Them?

Thousands of articles describing biomarkers predictive of treatment and prognostic of survival in cancer have been published, yet only a handful of biomarkers are currently used routinely in the clinic. Biomarkers need to be analytically standardized, validated, and clinically useful. This review will address the challenges and ways in which we can improve our discovery and translation of prospective biomarkers from the lab into validated diagnostic tests with a specific focus on patients diagnosed with glioblastoma and MGMT promoter methylation status. There has been long-held enthusiasm to use MGMT promoter methylation as a predictive biomarker for patients treated with the alkylating agent, temozolomide; however in the majority of centers around the world, this has not yet transpired.

Other paradigms: better treatments are identified by better trials: the value of randomized phase II studies

The emergence of many newer, molecularly targeted anticancer drugs requires that we rethink the way that we conduct phase II trials in oncology. In particular, we can no longer afford to advance drugs (or combinations) to phase III trials with a high risk of failure to improve on outcomes. Drawing on phase II trials of therapeutics for other chronic and progressive diseases in medicine, we find that a randomized design is essential not only for selecting agents for further study but also for optimizing the design (dose, patient population, and endpoints) of the subsequent phase III trials. We use the example of advanced nonsmall cell lung cancer to demonstrate how randomized phase II trials have already made an impact in oncology, whereas single-arm phase II trials have led to negative phase III trials in the same disease. Finally, we make the case that randomized phase II trials are feasible, as long as reasonable statistical standards are applied.