Search

Competing Interests: Last year, we organized a gathering of RPT expert physicians and scientists from academia and industry. The objective of the workshop was to propose how to replace existing absorbed dose constraints adopted from EBRT with new constraints and strategies derived from recent RPT experience. We aim to create normal tissue complication probability (NTCP) curves similar to those in Figure 1D for specific toxicities and types of RPT. However, in our examination of the literature, we found that most clinical trial reports unfortunately provide little or no information regarding tissue absorbed doses and insufficient detail regarding toxicities.6,13,23-25 We are actively collecting available patient-level data through data sharing and use agreements with our industry and academic partners, including coauthors and others, and we will analyze the data independently to limit potential bias and conflict of interest. We believe that routine reporting of estimates of absorbed dose delivered to tumors and organs at risk (eg, using single-photon emission computed tomography [SPECT]/computed tomography imaging-based methods) would improve analysis of the factors that might affect the efficacy of RPT agents for a given indication. Beyond this, it would provide the data needed for analysis of absorbed dose versus response or toxicity to better compare different agents and regimens.

Purpose: The use of biopsy-derived pharmacodynamic biomarkers is increasing in early-phase clinical trials. It remains unknown whether drug development is accelerated or enhanced by their use. We examined the impact of biopsy-derived pharmacodynamic biomarkers on subsequent drug development through a comprehensive analysis of phase I oncology studies from 2003 to 2010 and subsequent publications citing the original trials., Methods: We conducted a search to identify and examine publications of phase I oncology studies including the use of biopsy-derived pharmacodynamic biomarkers between 2003 and 2010. Characteristics of those studies were extracted and analyzed, along with outcomes from the biomarker data. We then compiled and reviewed publications of subsequent phase II and III trials citing the original phase I biomarker studies to determine the impact on drug development., Results: We identified 4,840 phase I oncology publications between 2003 and 2010. Seventy-two studies included a biopsy-derived pharmacodynamic biomarker. The proportion of biomarker studies including nondiagnostic biopsies increased over time (P = .002). A minimum of 1,873 tumor biopsies were documented in the 72 studies, 12 of which reported a statistically significant biomarker result. Thirty-three percent of studies (n = 24) were referenced by subsequent publications specifically with regard to the biomarkers. Only five positive biomarker studies were cited subsequently, and maximum tolerated dose was used for subsequent drug development in all cases., Conclusion: Despite their increased use, the impact of biopsy-derived pharmacodynamic biomarkers in phase I oncology studies on subsequent drug development remains uncertain. No impact on subsequent dose or schedule was demonstrated. This issue requires further evaluation, given the risk and cost of such studies., Competing Interests: Authors' disclosures of potential conflicts of interest are found in the article online at www.jco.org. Author contributions are found at the end of this article., (© 2015 by American Society of Clinical Oncology.)

Purpose: Patients with high-grade gliomas (HGG) are frequently excluded from first-in-human solid tumor trials because of perceived poor prognosis, excessive toxicities, concomitant drug interactions, and poor efficacy. We conducted an analysis of outcomes from select, single-agent phase I studies in patients with HGG. We compared outcomes to pooled analysis of published studies in solid tumors with various molecular and cytotoxic drugs evaluated as single agents or as combinations., Patient and Methods: Individual records of patients with recurrent HGG enrolled onto Adult Brain Tumor Consortium trials of single-agent, cytotoxic or molecular agents from 2000 to 2008 were analyzed for baseline characteristics, toxicities, responses, and survival., Results: Our analysis included 327 patients with advanced, refractory HGG who were enrolled onto eight trials involving targeted molecular (n=5) and cytotoxic (n=3) therapies. At enrollment, patients had a median Karnofsky performance score of 90 and median age of 52 years; 62% were men, 63% had glioblastoma, and the median number of prior systemic chemotherapies was one. Baseline laboratory values were in an acceptable range to meet eligibility criteria. Patients were on the study for a median of two cycles (range,

Purpose: We provide a comprehensive review of adaptive phase I clinical trials in oncology that used a statistical model to guide dose escalation to identify the maximum-tolerated dose (MTD). We describe the clinical setting, practical implications, and safety of such applications, with the aim of understanding how these designs work in practice., Methods: We identified 53 phase I trials published between January 2003 and September 2013 that used the continual reassessment method (CRM), CRM using escalation with overdose control, or time-to-event CRM for late-onset toxicities. Study characteristics, design parameters, dose-limiting toxicity (DLT) definition, DLT rate, patient-dose allocation, overdose, underdose, sample size, and trial duration were abstracted from each study. In addition, we examined all studies in terms of safety, and we outlined the reasons why escalations occur and under what circumstances., Results: On average, trials accrued 25 to 35 patients over a 2-year period and tested five dose levels. The average DLT rate was 18%, which is lower than in previous reports, whereas all levels above the MTD had an average DLT rate of 36%. On average, 39% of patients were treated at the MTD, and 74% were treated at either the MTD or an adjacent level (one level above or below)., Conclusion: This review of completed phase I studies confirms the safety and generalizability of model-guided, adaptive dose-escalation designs, and it provides an approach for using, interpreting, and understanding such designs to guide dose escalation in phase I trials., (© 2014 by American Society of Clinical Oncology.)

Purpose: All patients in phase I trials do not have equivalent susceptibility to serious drug-related toxicity (SDRT). Our goal was to develop a nomogram to predict the risk of cycle-one SDRT to better select appropriate patients for phase I trials., Patients and Methods: The prospectively maintained database of patients with solid tumor enrolled onto Cancer Therapeutics Evaluation Program-sponsored phase I trials activated between 2000 and 2010 was used. SDRT was defined as a grade ≥ 4 hematologic or grade ≥ 3 nonhematologic toxicity attributed, at least possibly, to study drug(s). Logistic regression was used to test the association of candidate factors to cycle-one SDRT. A final model, or nomogram, was chosen based on both clinical and statistical significance and validated internally using a bootstrapping technique and externally in an independent data set., Results: Data from 3,104 patients enrolled onto 127 trials were analyzed to build the nomogram. In a model with multiple covariates, Eastern Cooperative Oncology Group performance status, WBC count, creatinine clearance, albumin, AST, number of study drugs, biologic study drug (yes v no), and dose (relative to maximum administered) were significant predictors of cycle-one SDRT. All significant factors except dose were included in the final nomogram. The model was validated both internally (bootstrap-adjusted concordance index, 0.60) and externally (concordance index, 0.64)., Conclusion: This nomogram can be used to accurately predict a patient's risk for SDRT at the time of enrollment. Excluding patients at high risk for SDRT should improve the safety and efficiency of phase I trials.

Purpose: To evaluate the use and objectives of expansion cohorts in phase I cancer trials and to explore trial characteristics associated with their use., Methods: We performed a systematic review of MEDLINE and EMBASE, limiting studies to single-agent phase I trials recruiting adults and published after 2006. Eligibility assessment and data extraction were performed by two reviewers. Data were assessed descriptively, and associations were tested by univariable and multivariable logistic regression., Results: We identified 611 unique phase I cancer trials, of which 149 (24%) included an expansion cohort. The trials were significantly more likely to use an expansion cohort if they were published more recently, were multicenter, or evaluated a noncytotoxic agent. Objectives of the expansion cohort were reported in 74% of trials. In these trials, safety (80%), efficacy (45%), pharmacokinetics (28%), pharmacodynamics (23%), and patient enrichment (14%) were cited as objectives. Among expansion cohorts with safety objectives, the recommended phase II dose was modified in 13% and new toxicities were described in 54% of trials. Among trials aimed at assessing efficacy, only 11% demonstrated antitumor activity assessed by response criteria that was not previously observed during dose escalation., Conclusion: The utilization of expansion cohorts has increased with time. Safety and efficacy are common objectives, but 26% fail to report explicit aims. Expansion cohorts may provide useful supplementary data for phase I trials, particularly with regard to toxicity and definition of recommended dose for phase II studies.

The 3 + 3 design is the most common choice among clinicians for phase I dose-escalation oncology trials. In recent reviews, more than 95% of phase I trials have been based on the 3 + 3 design. Given that it is intuitive and its implementation does not require a computer program, clinicians can conduct 3 + 3 dose escalations in practice with virtually no logistic cost, and trial protocols based on the 3 + 3 design pass institutional review board and biostatistics reviews quickly. However, the performance of the 3 + 3 design has rarely been compared with model-based designs in simulation studies with matched sample sizes. In the vast majority of statistical literature, the 3 + 3 design has been shown to be inferior in identifying true maximum-tolerated doses (MTDs), although the sample size required by the 3 + 3 design is often orders-of-magnitude smaller than model-based designs. In this article, through comparative simulation studies with matched sample sizes, we demonstrate that the 3 + 3 design has higher risks of exposing patients to toxic doses above the MTD than the modified toxicity probability interval (mTPI) design, a newly developed adaptive method. In addition, compared with the mTPI design, the 3 + 3 design does not yield higher probabilities in identifying the correct MTD, even when the sample size is matched. Given that the mTPI design is equally transparent, costless to implement with free software, and more flexible in practical situations, we highly encourage its adoption in early dose-escalation studies whenever the 3 + 3 design is also considered. We provide free software to allow direct comparisons of the 3 + 3 design with other model-based designs in simulation studies with matched sample sizes.

Purpose: To describe current referral practices of oncologists to specialized palliative care (SPC) and define demographic characteristics, practice situations, and opinions associated with referral., Methods: Physician members of the Canadian Association of Medical Oncologists, Canadian Association of Radiation Oncologists, and Canadian Society of Surgical Oncology were invited to participate in an anonymous survey assessing SPC referral practices. Participants received two e-mailed and two mailed invitations., Results: The response rate was 72% (603 of 839 physicians); 37% were medical oncologists/hematologists, 50% were radiation oncologists, and 12% were surgical oncologists. Ninety-four percent reported that SPC was available to them, but only 37% reported that these services accepted patients on chemotherapy. Eighty-four percent referred terminally ill patients usually/always, but generally for uncontrolled symptoms or discharge planning late in the disease course. One third would refer to SPC earlier if it was renamed supportive care. Predictors of higher referral frequency included comprehensiveness of available SPC services (P = .004), satisfaction with SPC availability (P < .001), SPC acceptance of patients receiving chemotherapy (P < .001), and oncologist ease with referring patients to a palliative care service before they were close to death (P < .001). Controlling for specialty, predictors of referral at diagnosis or during chemotherapy, rather than later, included satisfaction with SPC service availability (P < .001) and SPC service acceptance of patients on chemotherapy (P < .001)., Conclusion: Oncologists referred patients frequently to SPC, but generally late in the disease course for patients with uncontrolled symptoms. Availability of comprehensive SPC, especially for patients receiving chemotherapy, and persisting definitional issues seem to be the main barriers preventing timely referral.

Unlabelled: PURPOSE; Evaluation of the communication and informed consent process in phase I clinical trial interviews to provide authentic, practice-based content for inclusion in a communication skills training intervention for health care professionals., Patients and Methods: Seventeen oncologists and 52 patients from five United Kingdom cancer centers consented to recording of phase I trial discussions. Following each consultation, clinicians completed questionnaires indicating areas they felt they had discussed, and researchers conducted semistructured interviews with patients examining their recall and understanding. Patients and oncologists also completed the Life Orientation Test-Revised questionnaire, measuring predisposition toward optimism. Independent researchers coded the consultations identifying discussion of key information areas and how well this was done. Observed levels of agreement were analyzed for each consultation between oncologist-coder, oncologist-patient, and patient-coder pairs., Results: In several key areas, information was either missing or had been explained but was interpreted incorrectly by patients. Discussion of prognosis was a frequent omission, with patients and coders significantly more likely to agree that oncologists had not discussed it (odds, 4.8; P < .001). In contrast, coders and oncologists were more likely to agree that alternate care plans to phase I trial entry had been explained (odds, 2.5; P = .023)., Conclusion: These data indicate that fundamental components of communication and information sharing about phase I trial participation are often missing from interviews. Important omissions included discussion of prognosis and ensuring patient understanding about supportive care. These findings will inform educational initiatives to assist communication about phase I trials.

Purpose: Physicians involved in the conduct of phase I studies of novel anticancer agents have raised concerns about the emergence of multi-institutional phase I trials and about using the optimal biologic dose (OBD) as an alternative to the maximum-tolerated dose (MTD) as the primary end point in early drug development. We sought to determine the factors associated with multi-institutional phase I studies and OBD determination., Patients and Methods: We reviewed all published phase I trials between January 1998 and June 2006 from two major clinical cancer journals. The following components from each trial were determined: number of participating sites, sponsor, nation where study was conducted, MTD or OBD established, number of patients accrued, mechanism of action of the studied agent, accrual time, and tumor type., Results: We identified 463 trials. Fifty-six percent were performed in single institutions. Only 30% reported accrual time. The number of patients enrolled on single institution studies was significantly lower than on multi-institutional studies (P < .05), but there was no difference in accrual time. There was no association between the number of institutions and the sponsor or the mechanism of drug action. National Institutes of Health-sponsored trials enrolled fewer patients per trial than pharmaceutical-sponsored trials (P < .05). Although 99% of trials with cytotoxic agents determined an MTD, only 64% of trials with targeted agents did., Conclusion: Multi-institutional phase I studies do not decrease the time to study completion and result in an increase in number of patients per trial. One third of trials with targeted agents failed to determine an MTD.

Purpose: We sought to describe complementary and alternative medicine (CAM) usage among phase I trial participants and to describe these patients' treatment decision-making preferences, awareness of prognosis, survival, and quality of life., Patients and Methods: Advanced cancer patients enrolling onto phase I trials were surveyed regarding biologically based CAM use. Decision-making preferences and awareness of prognosis were assessed using validated and/or standardized instruments. The Functional Assessment of Cancer Therapy-General instrument was used to assess quality of life. Univariate and multivariate analyses were performed to detect differences between CAM users and nonusers., Results: Of 212 interviewed patients, 34% (n = 72) described taking biologically based CAM. Median age of those taking biologically based CAM was 55 years, compared with 62 years for nonusers (P < .005). There were no statistically significant differences found between CAM usage and preferences for degree of patient involvement in medical decision making. Those patients who acknowledged that their deaths were likely to occur within 1 year were more likely to admit to prior CAM use (70% v 34%; P = .02). CAM users had poorer overall quality of life compared with nonusers (87.0 +/- 12.4 v 91.2 +/- 14.7; P = .007). No differences in survival were identified., Conclusion: Prior CAM use among phase I cancer trial patients studied was common and associated with age, stated acknowledgment of prognosis, and quality of life. Patients enrolling onto early-phase trials should be questioned about CAM use. Additional study is needed to determine the frequency of use of those biologically based CAM agents that threaten the accuracy of early-phase cancer trial data.

Purpose: The standard design for phase I trials of combined chemotherapy and radiation, which enters either three or six patients per dose level, has little statistical basis and is subject to opening and closing because of delayed toxicities that disrupt patient accrual. We compared the operating characteristics of this standard design and the time-to-event continual reassessment method (TITE-CRM) for dose-escalation trials of combination chemotherapy and radiation., Methods: The operating characteristics were determined by Monte Carlo simulation of 60,000 phase I trials., Results: Compared with the standard trial design, in studies with delayed toxicity (ie, where four or more patients are expected to enter onto the study during a single previously enrolled patient's observation for toxicity), TITE-CRM trials are significantly shorter when toxicity observation times are long, treat more patients at or above the maximum-tolerated dose, identify the maximum-tolerated dose (MTD) more accurately, and provide phase II information, but do not expose patients to significant additional risk. Estimation precision and overdose control of TITE-CRM increase as the design assumptions more closely resemble the true state of nature, but are reduced if, for instance, the toxicity of treatment has been grossly underestimated., Conclusion: Compared with the standard design, if there is any prior knowledge concerning the toxicity profile of a treatment, TITE-CRM can leverage it to produce more accurate estimates of the MTD and does not expose patients to significant excess risk, but requires timely communication between clinical investigators, data managers, and study statisticians.

Purpose: Alternatives to the standard design for conducting phase I trials are proposed with increasing frequency. This study was undertaken to determine how phase I trials are currently conducted and to provide a basis for evaluation of evolving methodology., Subjects and Methods: All published phase I trials from a single institution over a 3-year period were reviewed to determine the method of selection of the recommended dose for a phase II trial of a new agent, type and extent of toxicity, number of patients treated at the recommended dose, and clinical response., Results: All 23 published trials used the standard method of entering cohorts of patients at increasing dose levels and observing toxic effects to determine the dose recommended for phase II study. Among 610 patients, 26% were treated at or within 10% of the recommended dose and 35% were treated with less than 50% of the recommended dose or on a trial that yielded no recommended dose. Among 18 trials using agents previously tested in humans, fewer patients were treated at much less than the recommended dose. For trials in which myelosuppression was dose-limiting, the estimated probability of serious myelosuppression associated with the recommended dose ranged from 23% to 66%. Nineteen patients (3%) responded to therapy., Conclusion: This summary of phase I trials recently conducted at M.D. Anderson Cancer Center confirms the need for alternative methods, provides baseline information against which alternatively conducted trials can be compared, and demonstrates some practical clinical trial issues not generally considered when alternative methods are proposed.

Purpose: Choosing maximum-tolerated doses (MTDs) of agents to be administered in combination is more complicated than choosing the MTD for a single agent. This is because there are many combinations of doses that will be tolerated. We offer guidance in targeting specific MTD combinations, and suggest trial designs to achieve these targets., Methods: A graphical method based on a simple, previously described mathematical model is used to guide the phase I trial design. The method involves constructing a tolerable-dose diagram, which displays the toxicities that are expected to occur at various dose combinations. The data required for the method are the single-agent toxicity profiles of the agents. Designs for combinations of taxol with fluorouracil, carboplatin, doxorubicin, cyclophosphamide, and cisplatin are used to demonstrate the methods., Results: For all of the drugs considered here, leukopenia is dose-limiting or nearly dose-limiting. Consequently, no major improvement in total dose-intensity is achievable by combining these drugs. If leukopenia can be eliminated or substantially reduced by use of chemoprotective agents, then a cyclophosphamide/taxol combination appears promising from a dose-intensity point of view. For other combinations, the doses must be reduced from single-agent MTD levels. In the absence of biologic information such as concentrations needed for optimal modulation, it is suggested that single-agent MTDs be reduced approximately proportionately for each drug in the combination., Conclusion: Tolerable-dose diagrams are useful for planning phase I trials of combinations of agents. They can suggest which combinations are promising from a dose-intensity perspective, as well as dose-escalation schemes for combinations to be pursued for dose-intensity or other considerations.