Seymour, Lesley

10602 Background: Progressive disease (PD) according to RECIST 1.1 (Eisenhauer et al, 2009) is defined as one or more of (1) PD of measurable target lesions, (2) the presence of a new lesion (NL) or (3) the unequivocal PD of non-target disease (NT-PD). We explored the impact of these components, varying over time, on predicting overall survival (OS) in the RECIST database residing at EORTC (Bogaerts et al, 2009). Methods: Data was selected from 12 randomized clinical trials (3530 patients with breast, lung or colorectal cancer). A maximum of 5 target lesions was used to determine the sum of diameters. The following were calculated or assigned at each measurement time t: best response (BR) was best % improvement from baseline up to t (0% if no improvement - 100% if complete response (CR)); tumor growth (TG) was the weekly rate of increase from nadir to t (0 if no increase; irrespective of prior shrinkage), presence of NL (yes/no), and occurrence of NT-PD (yes/no); categories were not mutually exclusive. OS was analyzed by tumor type using a Cox regression model, adjusting for baseline sum, and including BR, TG, presence of NL and NT-PD as time dependent covariates. Results: Thirty-six percent of patients had NL, 26% had NT-PD, 11% achieved CR and 14% did not have shrinkage of target lesions, while 46% experienced TG (median strongest growth per patient of 0.5 mm/week). Regardless of tumor type, the presence of NL (Hazard Ratio (HR) ranging 1.4-2.5), NT-PD (HR 1.2-2.5) and TG (per 1mm/week increase; HR 1.1-1.4) were associated with worse OS, while achieving CR was associated with a longer OS (HR 0.2-0.8). Further analyses exploring the functional shape of the association between BR and TG, and OS are ongoing. This includes putting TG in contrast with the more usual % cutoff defining target PD. Conclusions: All three components of PD according to RECIST are independently strongly associated with OS. Quantification such as this will enable a better understanding of the role of each component (e.g. clinical aspect of NT-PD assessment) in PD evaluation. Work is ongoing to incorporate this information into an updated RECIST with enhanced prediction of subsequent survival.

Abstract Purpose: To review key aspects of the design and conduct of early clinical trials (ECT) of immunotherapy agents. Experimental Design: The Methodology for the Development of Innovative Cancer Therapies Task Force 2019 included experts from academia, nonprofit organizations, industry, and regulatory agencies. The review focus was on methodology for ECTs testing immune-oncology therapies (IO) used in combination with other IO or chemotherapy. Results: Although early successes have been seen, the landscape continues to be very dynamic, and there are ongoing concerns regarding the capacity to test all new drugs and combinations in clinical trials. Conclusions: Optimization of drug development methodology is required, taking into account early, late, and lower grade intolerable toxicities, novel response patterns, as well as pharmacodynamic data.

PURPOSE The mode of action of targeted cancer agents (TCAs) differs from classic chemotherapy, which leads to concerns about the role of RECIST in evaluating tumor response in trials with TCAs. We investigated the performance of RECIST using a pooled database from 50 clinical trials with at least one TCA. METHODS We examined the impact of the number of target lesions (TLs) on within-patient variability of tumor response. The prognostic effect of TL response (at 12 weeks or on study on the basis of a maximum five TLs) on survival was studied through landmark and time-dependent Cox models adjusted for baseline tumor load, occurrence of new lesions, or unequivocal progression of nontarget disease. RESULTS Data were obtained from 23,259 patients with cancer (36% lung, 28% colorectal, 11% breast, and 25% other); 15,620 received TCAs, predominantly transduction or angiogenesis inhibitors, as a single agent (37%), combined with other TCAs (7%), or as chemotherapy (56%); 28% received chemotherapy only; and 5% received best supportive care or placebo. A total of 17,222 patients contributed to the analyses. Within-patient variability decreased with increasing number of TLs, similarly for TCAs (with/without chemotherapy) and chemotherapy only. Mixed responses occurred proportionally in all treatment classes. Landmark analyses showed an ordinal relationship between percentage change from baseline to 12 weeks and overall survival, and demonstrated a clear distinction between tumor shrinkage and progressive disease according to RECIST. Time-dependent analysis showed no marked improvement in the ability to predict survival on the basis of TL tumor growth compared with nontarget progression or new lesion occurrence, regardless of treatment. Similar results were seen for major tumor types and different classes of TCAs. CONCLUSION This work reinforces that RECIST version 1.1 perform well for response assessment of TCAs.

2534 Background: The Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 were derived from an international collaborative effort supported by data from clinical trials (16 studies, 9147 patients) on cytotoxic chemotherapy (CT), providing a standard tool for response assessment. RECIST’s role has been questioned for TCA. Using a pooled individual patient database (IPD) from clinical trials performed by industry and cooperative groups, we assessed whether modifications to RECIST are required to evaluate antitumor activity of TCA. Methods: Data were collected from phase 2 and 3 clinical trials testing TCA in solid tumors. To study the occurrence of mixed responses, the variability of response of lesions within patients was studied. Furthermore, response was correlated with survival through landmark analyses and time dependent Cox models. Results: Clinical data were obtained from 23,259 patients, mainly with lung (36%), colorectal (28%) or breast cancer (11%). 15,620 patients (67%) received a TCA, mainly transduction or angiogenesis inhibitors, either as single agent (37%) or combined with other TCAs (7%) or CT (56%); 28% received CT only and 5% best supportive care or placebo. Within-patient variability reduced as the number of lesions used for response assessment increased, and did so similarly for TCAs (+/- CT) and CT. Mixed responses seemed to occur similarly across these treatment categories as well. Landmark analyses showed improving overall survival by % tumor shrinkage and a clear distinction between the effect of tumor shrinkage and progressive disease (PD) according to RECIST 1.1. This was confirmed by time dependent analysis. In addition target lesion growth showed no marked improvement in overall survival prediction over and above the other components of RECIST 1.1 PD (new lesions, non-target PD), regardless of treatment (TCA, CT or both) received. Similar results were seen focusing on major tumor types and classes of TCA. Conclusions: Using a large IPD dataset we demonstrated that RECIST 1.1 performs equally well for response assessment of TCA as for CT. No modifications are required.

Abstract Anticancer drugs are combined in an effort to treat a heterogeneous tumor or to maximize the pharmacodynamic effect. The development of combination regimens, while desirable, poses unique challenges. These include the selection of agents for combination therapy that may lead to improved efficacy while maintaining acceptable toxicity, the design of clinical trials that provide informative results for individual agents and combinations, and logistic and regulatory challenges. The phase I trial is often the initial step in the clinical evaluation of a combination regimen. In view of the importance of combination regimens and the challenges associated with developing them, the Clinical Trial Design (CTD) Task Force of the National Cancer Institute Investigational Drug Steering Committee developed a set of recommendations for the phase I development of a combination regimen. The first two recommendations focus on the scientific rationale and development plans for the combination regimen; subsequent recommendations encompass clinical design aspects. The CTD Task Force recommends that selection of the proposed regimens be based on a biologic or pharmacologic rationale supported by clinical and/or robust and validated preclinical evidence, and accompanied by a plan for subsequent development of the combination. The design of the phase I clinical trial should take into consideration the potential pharmacokinetic and pharmacodynamic interactions as well as overlapping toxicity. Depending on the specific hypothesized interaction, the primary endpoint may be dose optimization, pharmacokinetics, and/or pharmacodynamics (i.e., biomarker). Clin Cancer Res; 20(16); 4210–7. ©2014 AACR.

AbstractWe compiled and analyzed a database of cooperative group trials in advanced pancreatic cancer to develop historical benchmarks for overall survival (OS) and progression-free survival (PFS). Such benchmarks are essential for evaluating new therapies in a single-arm setting. The analysis included patients with untreated metastatic pancreatic cancer receiving regimens that included gemcitabine, between 1995 and 2005. Prognostic baseline factors were selected by their significance in Cox regression analysis. Outlier trial arms were identified by comparing individual 6-month OS and PFS rates against the entire group. The dataset selected for the generation of OS and PFS benchmarks was then tested for intertrial arm variability using a logistic-normal model with the selected baseline prognostic factors as fixed effects and the individual trial arm as a random effect. A total of 1,132 cases from eight trials qualified. Performance status and sex were independently significant for OS, and performance status was prognostic for PFS. Outcomes for one trial (NCCTG-034A) were significantly different from the other trial arms. When this trial was excluded, the remaining trial arms were homogeneous for OS and PFS outcomes after adjusting for performance status and sex. Benchmark values for 6-month OS and PFS are reported along with a method for using these values in future study design and analysis. The benchmark survival values were generated from a dataset that was homogeneous between trials. The benchmarks can be used to enable single-arm phase II trials using a gemcitabine platform, especially under certain circumstances. Such circumstances might be when a randomized control arm is not practically feasible, an early signal of activity of an experimental agent is being explored such as in expansion cohorts of phase I studies, and in patients who are not candidates for combination cytotoxic therapy. Clin Cancer Res; 20(16); 4176–85. ©2014 AACR.

Abstract The optimal design of phase II studies continues to be the subject of vigorous debate, especially studies of newer molecularly targeted agents. The observations that many new therapeutics “fail” in definitive phase III studies, coupled with the numbers of new agents to be tested as well as the increasing costs and complexity of clinical trials, further emphasize the critical importance of robust and efficient phase II design. The Clinical Trial Design Task Force (CTD-TF) of the National Cancer Institute (NCI) Investigational Drug Steering Committee (IDSC) has published a series of discussion papers on phase II trial design in Clinical Cancer Research. The IDSC has developed formal recommendations about aspects of phase II trial design that are the subject of frequent debate, such as endpoints (response versus progression-free survival), randomization (single-arm designs versus randomization), inclusion of biomarkers, biomarker-based patient enrichment strategies, and statistical design (e.g., two-stage designs versus multiple-group adaptive designs). Although these recommendations in general encourage the use of progression-free survival as the primary endpoint, randomization, inclusion of biomarkers, and incorporation of newer designs, we acknowledge that objective response as an endpoint and single-arm designs remain relevant in certain situations. The design of any clinical trial should always be carefully evaluated and justified based on characteristic specific to the situation. Clin Cancer Res; 16(6); 1764–9

Abstract 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.