Design Issues of Randomized Phase II Trials and a Proposal for Phase II Screening Trials

Gabapentin for smoking cessation

INTRODUCTION

We conducted a preliminary proof-of-concept study evaluating gabapentin for the treatment of tobacco dependence.

METHODS

Subjects (N = 80) were randomized to gabapentin (600 mg three times per day or 900 mg three times per day) or placebo. After a 2-week dose titration, the target dose was maintained for 9 weeks and then tapered over 1 week. Follow-up was for 12 weeks after the medication phase.

RESULTS

The study had high dropout rates with more than one half of participants in each arm discontinuing study. Gabapentin-treated participants exhibited lower abstinence rates than placebo-treated participants; however, this difference was not significant. Smoking reduction was observed across all treatment arms compared with baseline (p < .01) but did not differ across treatment groups.

DISCUSSION

Although not definitive, our findings suggest that gabapentin administered at these doses with this dosing regimen holds little promise for the treatment of tobacco dependence in a population of smokers seeking treatment.

High-dose cytarabine plus high-dose methotrexate versus high-dose methotrexate alone in patients with primary CNS lymphoma: a randomised phase 2 trial

BACKGROUND

Chemotherapy with high-dose methotrexate is the conventional approach to treat primary CNS lymphomas, but superiority of polychemotherapy compared with high-dose methotrexate alone is unproven. We assessed the effect of adding high-dose cytarabine to methotrexate in patients with newly diagnosed primary CNS lymphoma.

METHODS

This open, randomised, phase 2 trial was undertaken in 24 centres in six countries. 79 patients with non-Hodgkin lymphoma exclusively localised into the CNS, cranial nerves, or eyes, aged 18-75 years, and with Eastern Cooperative Oncology Group performance status of 3 or lower and measurable disease were centrally randomly assigned by computer to receive four courses of either methotrexate 3.5 g/m(2) on day 1 (n=40) or methotrexate 3.5 g/m(2) on day 1 plus cytarabine 2 g/m(2) twice a day on days 2-3 (n=39). Both regimens were administered every 3 weeks and were followed by whole-brain irradiation. The primary endpoint was complete remission rate after chemotherapy. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00210314.

FINDINGS

All randomly assigned participants were analysed. After chemotherapy, seven patients given methotrexate and 18 given methotrexate plus cytarabine achieved a complete remission, with a complete remission rate of 18% (95% CI 6-30) and 46% (31-61), respectively, (p=0.006). Nine patients receiving methotrexate and nine receiving methotrexate plus cytarabine achieved a partial response, with an overall response rate of 40% (25-55) and 69% (55-83), respectively, (p=0.009). Grade 3-4 haematological toxicity was more common in the methotrexate plus cytarabine group than in the methotrexate group (36 [92%] vs six [15%]). Four patients died of toxic effects (three vs one).

INTERPRETATION

In patients aged 75 years and younger with primary CNS lymphoma, the addition of high-dose cytarabine to high-dose methotrexate provides improved outcome with acceptable toxicity compared with high-dose methotrexate alone.

FUNDING

Swiss Cancer League.

Consensus report of the national cancer institute clinical trials planning meeting on pancreas cancer treatment

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer mortality, despite significant improvements in diagnostic imaging and operative mortality rates. The 5-year survival rate remains less than 5% because of microscopic or gross metastatic disease at time of diagnosis. The Clinical Trials Planning Meeting in pancreatic cancer was convened by the National Cancer Institute's Gastrointestinal Cancer Steering Committee to discuss the integration of basic and clinical knowledge in the design of clinical trials in PDAC. Major emphasis was placed on the enhancement of research to identify and validate the relevant targets and molecular pathways in PDAC, cancer stem cells, and the microenvironment. Emphasis was also placed on developing rational combinations of targeted agents and the development of predictive biomarkers to assist selection of patient subsets. The development of preclinical tumor models that are better predictive of human PDAC must be supported with wider availability to the research community. Phase III clinical trials should be implemented only if there is a meaningful clinical signal of efficacy and safety in the phase II setting. The emphasis must therefore be on performing well-designed phase II studies with uniform sets of basic entry and evaluation criteria with survival as a primary endpoint. Patients with either metastatic or locally advanced PDAC must be studied separately.

A comparison of phase II study strategies

The traditional oncology drug development paradigm of single arm phase II studies followed by a randomized phase III study has limitations for modern oncology drug development. Interpretation of single arm phase II study results is difficult when a new drug is used in combination with other agents or when progression-free survival is used as the endpoint rather than tumor shrinkage. Randomized phase II studies are more informative for these objectives but increase both the number of patients and time required to determine the value of a new experimental agent. In this article, we compare different phase II study strategies to determine the most efficient drug development path in terms of number of patients and length of time to conclusion of drug efficacy on overall survival.

A randomized, double-blind, placebo-controlled phase II study of vandetanib plus docetaxel/prednisolone in patients with hormone-refractory prostate cancer

Vandetanib (ZACTIMA) is a once-daily oral anticancer drug that selectively inhibits vascular endothelial growth factor receptor, epidermal growth factor receptor, and rearranged during transfection signaling. This randomized (1:1), double-blind study evaluated vandetanib (100 mg/day) or placebo in combination with docetaxel (D; 75 mg/m(2) every 3 weeks) and prednisolone (P; 2 x 5 mg/day) in 86 patients with metastatic hormone-refractory prostate cancer (mHRPC). The primary assessment was prostate-specific antigen (PSA) response (confirmed reduction of >or=50% from baseline) and a greater number of patients showed a PSA response with placebo + DP (67%) versus vandetanib + DP (40%); hazard ratio = 2.23 (one-sided 80% confidence limit = 2.90; one-sided p = 0.99). More patients experienced progression events (disease progression or death from any cause) with vandetanib + DP (65%) versus placebo + DP (60%); hazard ratio = 1.13 (one-sided 80% confidence limit = 1.44; one-sided p = 0.67). The overall incidence of adverse events was similar in both groups, although more patients experienced adverse events, leading to permanent discontinuation with vandetanib + DP (28%) versus placebo + DP (12%). However, the safety and tolerability profile for vandetanib was similar to that previously reported; adverse events that occurred more frequently in the vandetanib + DP arm were hypertension (14% vs. 2%), erythematous rash (14% vs. 2%), and exfoliative rash (12% vs. 2%). In this study of patients with mHRPC, vandetanib + DP did not demonstrate any efficacy benefit, compared with placebo + DP.

Comparison of power between randomized discontinuation design and upfront randomization design on progression-free survival

PURPOSE

Enrichment based on molecular characteristics has emerged as an important inclusion criterion in phase II trials of targeted anticancer agents. In this study, we evaluate a well-described method of population enrichment by tumor growth characteristics in the early development stage of targeted cytostatic agents.

METHODS

For some solid tumors, such as pancreatic carcinoma, using a time-to-event end point (eg, time to disease progression) to evaluate the efficacy of a cytostatic agent in a phase II trial is more relevant than clinical response by Response Evaluation Criteria in Solid Tumors. In this setting, we compared the power of the randomized discontinuation and upfront randomization designs under two previously proposed tumor growth models for treatment effect when the end point is time-to-event.

RESULTS

By selecting patients with more homogeneous tumor growth characteristics, the randomized discontinuation design is more efficient than the upfront randomization design when treatment benefit is restricted to slow-growing tumors. Under a model where only a subset of patients expressing the molecular target are sensitive to the agent, the randomized discontinuation design is more powerful than the upfront randomization design when the treatment effect is small; and vice versa when the treatment effect is moderate to large.

CONCLUSION

For selected targeted agents where a bioassay to select patients expressing the specific molecular target is not available, the randomized discontinuation design is a feasible alternative patient enrichment strategy in certain disease settings and provides a reasonable platform to evaluate drugs before phase III testing.

Current issues in oncology drug development, with a focus on Phase II trials

In this commentary we discuss several challenges that are of current relevance to the design of clinical trials in oncology. We argue that the compartmentalization of trials into the three standard phases, with non overlapping aims, is not necessary and in fact may slow the clinical development of agents. Combined Phase I/II trials and/or Phase I trials that at minimum collect efficacy data and more optimally include a preliminary measure of efficacy in dosing determination should be more widely utilized. Similarly, we posit that randomized Phase II trials should be used more frequently, as opposed to the traditional historical single arm Phase II trial that usually does not have a valid comparison group. The use of non binary endpoints is a simple modification that can improve the efficiency of early phase trials. The heterogeneity in scientific goals and contexts in early phase oncology trials is considerable, and the potential to improve the design to match these goals is great. We review these and other issues in the context of 5 manuscripts related to Phase II trials published in this volume. Our overall premise is that the potential benefits associated with the oncology clinical trial community moving away from the one size fits all paradigm of trial design are great, and that more flexible and efficient designs tailored to match the goals of each study are currently available and being used successfully.

Suggested response criteria for phase II antitumor drug studies for neurofibromatosis type 2 related vestibular schwannoma

Neurofibromatosis type 2 (NF2) is a tumor suppressor gene syndrome characterized by multiple schwannomas, especially vestibular schwannomas (VS), and meningiomas. Anticancer drug trials are now being explored, but there are no standardized endpoints in NF2. We review the challenges of NF2 clinical trials and suggest possible response criteria for use in initial phase II studies. We suggest two main response criteria in such trials. Objective radiographic response is defined as a durable 20% or greater reduction in VS volume based on post-contrast T1-weighted MRI images collected with 3 mm or finer cuts through the internal auditory canal. Hearing response is defined as a statistically significant improvement in word recognition scores using 50-word recorded lists in audiology. A possible composite endpoint incorporating both radiographic response and hearing response is outlined. We emphasize pitfalls in response assessment and suggest guidelines to minimize misinterpretations of response. We also identify research goals in NF2 to facilitate future trial conduct, such as identifying the expectations for time to tumor progression and time to measurable hearing loss in untreated NF2-related VS, and the relation of both endpoints to patient prognostic factors (such as age, baseline tumor volume, and measures of disease severity). These data would facilitate future use of endpoints based on stability of tumor size and hearing, which might be more appropriate for testing certain drugs. We encourage adoption of standardized endpoints early in the development of phase II trials for this population to facilitate comparison of results across trials of different agents.

Alternate endpoints for screening phase II studies

Phase II trials are screening trials that seek to identify agents with sufficient activity to continue development and those for which further evaluation should be halted. Although definitive phase III trials use progression-free or overall survival to confirm clinical benefit, earlier endpoints are preferable for phase II trials. Traditionally, tumor shrinkage of a predetermined degree (response) has been used as a surrogate of eventual survival benefit based on the observation that high response rates (RR), and particularly complete responses, in the phase II setting resulted in survival benefit in subsequent phase III trials. Recently, some molecularly targeted agents have shown survival and clinical benefit despite very modest RRs in early clinical trials. These observations provide a major conundrum, with concerns of inappropriate termination of development for active agents with low RRs being balanced by concerns of inactive agents being taken to late-phase development with resultant increases in the failure rate of phase III trials. Numerous alternate or complementary endpoints have been explored, incorporating multinomial endpoints (including progression and response), progression-free survival, biomarkers, and, more recently, evaluation of tumor size as a continuous variable. In this review, we discuss the current status of phase II endpoints and present retrospective analyses of two international gastrointestinal cancer studies showing the potential utility of one novel approach. Alternate endpoints, although promising, require additional evaluation and prospective validation before their use as a primary endpoint for phase II trials.

Effective incorporation of biomarkers into phase II trials

The incorporation of biomarkers into the drug development process will improve understanding of how new therapeutics work and allow for more accurate identification of patients who will benefit from those therapies. Strategically planned biomarker evaluations in phase II studies may allow for the design of more efficient phase III trials and better screening of therapeutics for entry into phase III development, hopefully leading to increased chances of positive phase III trial results. Some examples of roles that a biomarker can play in a phase II trial include predictor of response or resistance to specific therapies, patient enrichment, correlative endpoint, or surrogate endpoint. Considerations for using biomarkers most effectively in these roles are discussed in the context of several examples. The substantial technical, logistic, and ethical challenges that can be faced when trying to incorporate biomarkers into phase II trials are also addressed. A rational and coordinated approach to the inclusion of biomarker studies throughout the drug development process will be the key to attaining the goal of personalized medicine.

Randomized phase II designs

As the use of molecularly targeted agents, which are anticipated to increase overall survival (OS)and progression-free survival (PFS) but not necessarily tumor response, has increased in oncology, there has been a corresponding increase in the recommendation and use of randomized phase II designs. Such designs reduce the potential for bias, existent in comparisons with historical controls, but also substantially increase the sample size requirements. We review the principal statistical designs for historically controlled and randomized phase II trials, along with their advantages, disadvantages, and statistical design considerations. We review the arguments for and against the use of randomization in phase II studies, the situations in which the use of historical controls is preferred, and the situations in which the use of randomized designs is preferred. We review methods used to calculate predicted OS or PFS values from historical controls, adjusted so as to be appropriate for an experimental sample with particular prognostic characteristics. We show how adjustment of the type I and type II error bounds for randomized studies can facilitate the detection of appropriate target increases in median PFS or OS with sample sizes appropriate for phase II studies. Although there continue to be differences among investigators concerning the use of randomization versus historical controls in phase II trials, there is agreement that each approach will continue to be appropriate, and the optimal approach will depend upon the circumstances of the individual trial.

Optimising the design of phase II oncology trials: the importance of randomisation

Oncology trial end-points continue to receive considerable attention, as illustrated by the development and revisions to the RECIST criteria. In this article, we focus the reader away from the issue of end-points for phase II trials and towards what we believe to be an even more important issue, the fundamental need for randomisation in phase II oncology trials, ideally with blinding and dose-ranging. We present arguments to support the proposition that randomisation will enable greater clarity in the interpretation of the phase II trial results, as well as allowing for more precise estimates of the effect size and sample size requirements for definitive phase III trials. Randomisation will also reduce potential bias resulting from inter-trial variability, which inflates both type I and II errors if historical controls are utilised. In the context of a randomised blinded trial, the exact choice of end-point is less critical, although we favour end-points such as the change in tumour size or progression status at a fixed early time point (i.e. 8-12 weeks after randomisation). Although end-points based on RECIST criteria can and should be utilised in randomised phase II trials, we do not believe that revision of the RECIST criteria will result in a fundamental improvement in drug development decisions in the absence of randomised clinical trials at the phase II stage of drug development.

Statistics in brief: the importance of sample size in the planning and interpretation of medical research

The increasing volume of research by the medical community often leads to increasing numbers of contradictory findings and conclusions. Although the differences observed may represent true differences, the results also may differ because of sampling variability as all studies are performed on a limited number of specimens or patients. When planning a study reporting differences among groups of patients or describing some variable in a single group, sample size should be considered because it allows the researcher to control for the risk of reporting a false-negative finding (Type II error) or to estimate the precision his or her experiment will yield. Equally important, readers of medical journals should understand sample size because such understanding is essential to interpret the relevance of a finding with regard to their own patients. At the time of planning, the investigator must establish (1) a justifiable level of statistical significance, (2) the chances of detecting a difference of given magnitude between the groups compared, ie, the power, (3) this targeted difference (ie, effect size), and (4) the variability of the data (for quantitative data). We believe correct planning of experiments is an ethical issue of concern to the entire community.

Found in translation: Integrating laboratory and clinical oncology research

Translational research in medicine aims to inform the clinic and the laboratory with the results of each other’s work, and to bring promising and validated new therapies into clinical application. While laudable in intent, this is complicated in practice and the current state of translational research in cancer shows both striking success stories and examples of the numerous potential obstacles as well as opportunities for delays and errors in translation. This paper reviews the premises, promises, and problems of translational research with a focus on radiation oncology and suggests opportunities for improvements in future research design.

Randomized phase II trials with a prospective control

We consider phase II trials randomizing patients between a prospective control and an experimental therapy. Proposed are two-stage designs allowing for early termination of the study when the experimental arm does not show promising efficacy at the interim analysis. By using exact binomial distributions, the design characteristics, such as type I error and power, are exactly calculated. Given response probabilities for two arms, we define minimax and optimal designs that satisfy a prespecified restriction on type I and II error probabilities. These designs are randomized phase II trial analogs of Simon's designs that were proposed for single-arm phase II trials. The methods for two-arm trials are easily extended to multi-arm trials with one control and K (> or =2) experimental arms. Some phase II trials are taken as real examples.

A review of phase 2-3 clinical trial designs

This article reviews phase 2-3 clinical trial designs, including their genesis and the potential role of such designs in treatment evaluation. The paper begins with a discussion of the many scientific flaws in the conventional phase 2 --> phase 3 treatment evaluation process that motivate phase 2-3 designs. This is followed by descriptions of some particular phase 2-3 designs that have been proposed, including two-stage designs to evaluate one experimental treatment, a design that accommodates both frontline and salvage therapy in oncology, two-stage select-and-test designs that evaluate several experimental treatments, dose-ranging designs, and a seamless phase 2-3 design based on both early response-toxicity outcomes and later event times. A general conclusion is that, in many circumstances, a properly designed phase 2-3 trial utilizes resources much more efficiently and provides much more reliable inferences than conventional methods.

Meta-analysis of phase II cooperative group trials in metastatic stage IV melanoma to determine progression-free and overall survival benchmarks for future phase II trials

PURPOSE

Objective tumor response rates observed in phase II trials for metastatic melanoma have historically not provided a reliable indicator of meaningful survival benefits. To facilitate using overall survival (OS) or progression-free survival (PFS) as an endpoint for future phase II trials, we evaluated historical data from cooperative group phase II trials to attempt to develop benchmarks for OS and PFS as reference points for future phase II trials.

PATIENTS AND METHODS

Individual-level and trial-level data were obtained for patients enrolled onto 42 phase II trials (70 trial arms) that completed accrual in the years 1975 through 2005 and conducted by Southwest Oncology Group, Eastern Cooperative Oncology Group, Cancer and Leukemia Group B, North Central Cancer Treatment Group, and the Clinical Trials Group of the National Cancer Institute of Canada. Univariate and multivariate analyses were performed to identify prognostic variables, and between-trial(-arm) variability in 1-year OS rates and 6-month PFS rates were examined.

RESULTS

Statistically significant individual-level and trial-level prognostic factors found in a multivariate survival analysis for OS were performance status, presence of visceral disease, sex, and whether the trial excluded patients with brain metastases. Performance status, sex, and age were statistically significant prognostic factors for PFS. Controlling for these prognostic variables essentially eliminated between-trial variability in 1-year OS rates but not in 6-month PFS rates.

CONCLUSION

Benchmarks are provided for 1-year OS or OS curves that make use of the distribution of prognostic factors of the patients in the phase II trial. A similar benchmark for 6-month PFS is provided, but its use is more problematic because of residual between-trial variation in this endpoint.

Cetuximab plus gemcitabine and cisplatin compared with gemcitabine and cisplatin alone in patients with advanced pancreatic cancer: a randomised, multicentre, phase II trial

BACKGROUND

Preclinical data have suggested a synergistic effect of cetuximab combined with gemcitabine and cisplatin and clinical data have shown a substantial improvement in response and survival when gemcitabine is combined with a platinum analogue compared with gemcitabine alone. The aim of this study was to assess the activity and feasibility of a combination of cetuximab with gemcitabine and cisplatin compared with use of gemcitabine and cisplatin alone for the treatment of advanced pancreatic cancer.

METHODS

In a multicentre, randomised phase II trial, 84 patients with advanced pancreatic cancer were randomly assigned to either 250 mg/m2 cetuximab weekly, after a loading dose of 400 mg/m2, plus 1000 mg/m2 gemcitabine and 35 mg/m2 cisplatin on days 1 and 8 of a 21-day cycle or to the same chemotherapeutic regimen without cetuximab. The primary endpoint was objective response (defined as the proportion of patients whose best response was either partial response or complete response). Secondary endpoints included disease control (defined as the proportion of patients whose best response was either partial response, complete response, or stable disease), progression-free survival, and overall survival. All assessments of response at each site were done blindly by a local experienced radiologist who was not directly involved in the trial. Responses were measured according to an intention-to-treat analysis. This trial is registered with the Clinical Trial registry, number NCT00536614.

FINDINGS

29 men and 13 women were randomly assigned to cetuximab plus gemcitabine and cisplatin (median age 61 years [range 38-78]) and 22 men and 20 women were randomly assigned to gemcitabine and cisplatin (median age 64 years [range 40-76]). Seven of 40 (17.5%) patients had an objective response in the cetuximab group (95% CI 7.3-32.8) and five of 41 (12.2%) patients had an objective response in the non-cetuximab group (95% CI 4.1-26.2). No significant difference was noted between the groups both for objective response (5.3% higher in the cetuximab group [95% CI -16.5 to 27.1]; chi2 test=0.360; p=0.549) or for disease control (3.5% higher in the non-cetuximab group [-34.0% to 27.0%]; 0.446; p=0.504). Overall median follow-up was 11.8 months (range 2.5-18.5). No significant differences between the groups were noted in median progression-free survival (hazard ratio 0.96, 95% CI 0.60-1.52, p=0.847) or in median overall survival (0.91, 0.54-1.55, p=0.739): median progression-free survival was 3.4 months (95% CI 2.4-5.1) in the cetuximab group and 4.2 months (2.6-5.4) in the non-cetuximab group; median overall survival was 7.5 months (5.1-8.8) and 7.8 months (5.3-15.0), respectively. 33 patients from both groups had at least one grade 3-4 toxic effect.

INTERPRETATION

The addition of cetuximab to a combination of gemcitabine and cisplatin does not increase response or survival for patients with advanced pancreatic cancer. Although toxic effects were not increased by cetuximab, this combination should not be further assessed in phase III trials.

Blood and Marrow Transplant Clinical Trials Network State of the Science Symposium 2007

Outcomes of hematopoietic cell transplantation are steadily improving. New techniques have reduced transplant toxicities, and there are new sources of hematopoietic stem cells from unrelated donors. In June 2007 the Blood and Marrow Transplant Clinical Trials Network convened a State of the Science Symposium of more than 200 participants in Ann Arbor to identify the most compelling clinical research opportunities in the field. This report summarizes the symposium's discussions and identifies eleven high priority clinical trials that the network plans to pursue over the course of the next several years.

A three-outcome design for randomized comparative phase II clinical trials

Randomized designs have been increasingly called for use in phase II oncology clinical trials to protect against potential patient selection bias. However, formal statistical comparison is rarely conducted due to the sample size restriction, despite its appeal. In this paper, we offer an approach to sample size reduction by extending the three-outcome design of Sargent et al. (Control Clin. Trials 2001; 22:117-125) for single-arm trials to randomized comparative trials. In addition to the usual two outcomes of a hypothesis testing (rejecting the null hypothesis or rejecting the alternative hypothesis), the three-outcome comparative design allows a third outcome of rejecting neither hypotheses when the testing result is in some 'grey area' and leaves the decision to the clinical judgment based on the overall evaluation of trial outcomes and other relevant factors. By allowing a reasonable region of uncertainty, the three-outcome design enables formal statistical comparison with considerably smaller sample size, compared to the standard two-outcome comparative design. Statistical formulation of the three-outcome comparative design is discussed for both the single-stage and two-stage trials. Sample sizes are tabulated for some common clinical scenarios.

Design and conduct of phase II studies of targeted anticancer therapy: recommendations from the task force on methodology for the development of innovative cancer therapies (MDICT)

The Methodology for the Development of Innovative Cancer Therapies (MDICT) task force considered aspects of the design and conduct of phase II studies for molecular targeted agents during their 2007 meeting. The task force recommended that multinomial endpoints and designs should be considered for phase II studies of targeted agents, that both single arm as well as randomised designs remain appropriate in certain settings, and that further assessment of novel endpoints (tumour growth kinetic assessment, biomarker or functional imaging) and designs (randomised discontinuation or Bayesian adaptive design) be encouraged. The MDICT cautioned on the use of small randomised trials which have a number of statistical pitfalls and dangers and strongly encouraged the complete reporting, including negative trials, in the scientific literature.

Clinical trials of active cancer immunotherapy

Active immunotherapy of cancer needs its own clinical trials' methodology. The standard methodology paradigm for clinical trials in oncology was developed for cytotoxic drugs, which differ dramatically from cancer vaccines in their mode of action and toxicity profile. To minimize the risk of overlooking benefits for patients, Mackiewicz and Nawrocki invite to open discussion on vaccine trials' methodology. Our point of view is based on several Phase I and II trials with hundreds of melanoma patients treated with allogenic cellular vaccine genetically modified with cytokine genes. We feel that a simplified two-stage clinical trial design without a separate Phase I is justified. In the first stage, preliminary efficacy together with proof-of-principle and feasibility issues could be addressed. For real efficacy assessment, careful consideration of end points is necessary. Immunologic responses and objective clinical responses are not the best measures of vaccine efficacy for many patients who benefit from treatment. Randomized single institution studies with time-to-event end points are probably well suited for such combined Phase I/II studies. In the second stage trial (Phase III), the final efficacy analysis with comparator arm is needed.

Are There Circumstances in Which Phase 2 Study Results Should Be Practice-Changing?

New pharmaceuticals, innovative combinations of approved agents, and novel treatment modalities have resulted in a marked increase in the need for clinical trials. Evidence for treatment efficacy is best derived from large phase 3 randomized, controlled clinical trials. However, phase 3 investigations are lengthy and expensive, and consume patient resources. Furthermore, some diseases and treatment indications are rare, and adequate numbers of patients for a definitive phase 3 trial do not exist. Consequently, it is imperative for clinicians to understand phase 2 trial design, since their interpretation is required to apply the findings in clinical practice appropriately. The complexity of phase 2 studies is explored, including unique designs, possible use of randomization, and other key elements necessary for interpretation of phase 2 trials. Specific examples and application of these concepts are discussed in this review.

Current therapeutic strategies for acute myeloid leukaemia

Improvements in survival in adult acute myeloid leukaemia (AML) have yet to be gleaned from either refinements in the understanding of the pathophysiology of the disease or from the expanding pool of targeted therapies. Outcomes have remained particularly dismal in older patients. Ongoing and planned trials will assess the effects of drugs targeting biological pathways whose clinical importance may vary as a function of the unique genotype and phenotype of each case of AML. The success of these ventures will ultimately require well-designed clinical trials in subsets of patients with risk being dependent not only on age and cytogenetics, but on additional, increasingly quantifiable biological variables. Inhibitors of fms-like tyrosine kinase-3, farnesyl transferase, apoptotic and angiogenic pathways are being studied alone and in combination with chemotherapy. Biological therapies, including monoclonal antibodies, peptide vaccines and interleukin-2, are undergoing evaluation. The role of autologous as well as allogeneic myeloablative and reduced-intensity transplantation continues to be defined. Several potentially useful new cytotoxic agents are being introduced. Critically important to advancing the field in light of such an increasing number of choices is a reassessment of traditional phase II trial designs so that more efficient evaluation of new therapies may take place, even as well-designed phase III trials continue to be performed.

Improving the design of phase II trials of cytostatic anticancer agents

This paper examines the design of phase II trials in oncology and recommends departing from the traditional uncontrolled trial design. Entrance into phase II clinical evaluation represents a key milestone in the development of any new cancer therapy. As novel molecular-targeted therapies are introduced, whose primary action is to slow the growth of tumors, it will be important to ensure that the clinical trial design will effectively capture any clinical benefit of these agents. The objective of a phase II trial should, in addition to identifying active therapies, be extended to identifying those that are likely to be successful in pivotal trials. It is therefore necessary to quantify the likelihood of either incorrectly halting the development of an active agent or continuing development of an ineffective agent. We believe only randomized studies with comparative intent and including a concurrent active control, can reliably assess these risks corresponding to significance and power. Given that the objective of phase II studies is to identify promising treatments, it is important not be constrained by conventional levels of significance. This paper will review the various approaches to phase II trial design in oncology and provide a framework for fully powered randomized trials of a moderate size. For example, a randomized trial of just 100 patients could lead to the termination of development of 90% of inactive agents whereas at least 80% of agents with a meaningful and realistic increase in progression-free survival would be identified for confirmatory study. We believe randomized studies with progression-free survival endpoints are the most powerful and economical method of determining the clinical activity of new cytostatic agents.

Drug development in oncology: classical cytotoxics and molecularly targeted agents

There is an apparent need to improve the speed and efficiency of oncological drug development. Furthermore, strategies traditionally applied to the development of standard cytotoxic chemotherapy may not be appropriate for molecularly targeted agents. This is particularly the case for exploratory Phase 1 and 2 trials. Conventional approaches to determine dose based on maximum tolerability and efficacy based on objective tumour response may not be suitable for targeted agents, since many of them have a wide therapeutic index and inhibit tumour growth without demonstrable cytotoxicity. Instead, exploratory trials of targeted agents may have to focus on other end-points such as pharmacological effects and disease stabilization. Thus, there is an increasing interest in making the best possible use of biomarkers and pharmacogenomics in early phases of drug development.

Measuring response in a post-RECIST world: from black and white to shades of grey

The unprecedented pace of therapeutic development in oncology has created a climate in which the traditional methods of evaluating agent activity might no longer be adequate. How is the field transitioning to new endpoints in early drug development and what are the difficulties in this transition? Here, we will explore the historical context for the current criteria for tumour response evaluation and some of the pitfalls in using these standards when testing newer anticancer agents for activity. We will argue that the current drug development environment dictates different outcome measurements and therefore more imaginative and rigorous early-phase trial designs.

Acute myeloblastic leukemia in patients with multiple myeloma

Background

The continuum of anti-HER2 agents is a standard treatment of HER2 + metastatic breast cancer (MBC). This study evaluated the efficacy of lapatinib plus vinorelbine in patients progressed on both trastuzumab and lapatinib treatments.

Methods

A total of 149 patients were randomly assigned to lapatinib with vinorelbine (LV) (n = 75; lapatinib, 1000 mg daily; vinorelbine 20 mg/m² D1, D8 q3w) or vinorelbine (V) (n = 74; 30 mg/m² D1, D8 q3w). The primary endpoint was progression-free survival (PFS) rate at 18 weeks.

Results

The median number of previous anti-HER2 therapies was 2 (range 2–5). There was no significant difference in PFS rate at 18 weeks between LV and V arms (45.9% vs 38.9%, p = 0.40). ORR was 19.7% in LV arm, and 16.9% in V arm (p = 0.88). PFS and OS did not differ between two arms (LV vs V; median PFS, 16 vs 12 weeks, HR = 0.86, 95% CI 0.61–1.22; median OS, 15.0 vs 18.9 months, HR = 1.07, 95% CI 0.72–1.58). Toxicity profiles were similar in both arms and all were manageable.

Conclusions

Lapatinib plus vinorelbine treatment was tolerable; however, it failed to demonstrate the clinical benefits over vinorelbine alone in patients with HER2 + MBC after progression on both trastuzumab and lapatinib.

Clinical trial registration

ClinicalTrials.gov number NCT01730677.