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Pragmatic dose-escalation methods incorporating relative dose intensity assessment for molecularly targeted agents in phase I trials.

ABSTRACT: The recommended phase 2 doses of molecularly targeted agents, determined by using an ordinal dose-finding method that only uses toxicity data at first cycle, may not be optimal. Some researchers have proposed the use of relative dose intensity that can account for late-onset, cumulative, and low-grade toxicities to determine the recommended phase 2 dose (RP2D). In this study, we proposed two dose escalation methods based on the observed relative dose intensities (RDIs) between the pre-specified intervals (cycles) for toxicity evaluation used in combination with DLT evaluation in the first cycle. First, we propose the modified 3 + 3 design that incorporates longitudinal RDI assessment. Second, we propose the sequential assessment method for longitudinal RDI (SARDI) to achieve faster dose escalation compared to that of the modified 3 + 3 design. Simulation studies demonstrated that the SARDI was, in many cases, superior to the ordinal and modified 3 + 3 designs in respect to the selection rate of true RP2D and study period. The two proposed methods could also in some cases decrease the average number of patients enrolled in the trial compared to that of the ordinary 3 + 3 design. Incorporation of the RDI assessment into the 3 + 3 design is not difficult and does not require the use of complex statistical techniques. Therefore, we believe that investigators who routinely use the 3 + 3 design in practice can easily use our proposed methods.

SUBMITTER: Hirakawa A

PROVIDER: S-EPMC6883296 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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Pragmatic dose-escalation methods incorporating relative dose intensity assessment for molecularly targeted agents in phase I trials.

Hirakawa Akihiro A Tanaka Yuichi Y Kaneko Shuhei S

Contemporary clinical trials communications 20191112

The recommended phase 2 doses of molecularly targeted agents, determined by using an ordinal dose-finding method that only uses toxicity data at first cycle, may not be optimal. Some researchers have proposed the use of relative dose intensity that can account for late-onset, cumulative, and low-grade toxicities to determine the recommended phase 2 dose (RP2D). In this study, we proposed two dose escalation methods based on the observed relative dose intensities (RDIs) between the pre-specified ...[more]

PMID: 31799475

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Project description:BackgroundA key challenge in phase I trials is maintaining rapid escalation in order to avoid exposing too many patients to sub-therapeutic doses, while preserving safety by limiting the frequency of toxic events. Traditional rule-based designs require temporarily stopping recruitment whilst waiting to see whether enrolled patients develop toxicity. This can be both inefficient and introduces logistic challenges to recruitment in the clinic. We describe a novel two-stage dose assignment procedure designed for a phase I clinical trial (STARPAC), where a good estimation of prior was possible.MethodsThe STARPAC design uses rule-based design until the first patient has a dose limiting toxicity (DLT) and then switches to a modified CRM, with rules to handle patient recruitment during follow-up of earlier patients. STARPAC design is compared via simulations with the TITE-CRM and 3 + 3 methods in various toxicity estimate (T1-5), rate of recruitment (R1-2), and DLT events timing (DT1-4), scenarios using several metrics: accuracy of maximum tolerated dose (MTD), numbers of DLTs, number of patients enrolled and those missed; duration of trial; and proportion of patients treated at the therapeutic dose or MTD.ResultsThe simulations suggest that STARPAC design performed well in MTD estimation and in treating patients at the highest possible therapeutic levels. STARPAC and TITE-CRM were comparable in the number of patients required and DLTs incurred. The 3 + 3 design often had fewer patients and DLTs although this is due to its low escalation rate leading to poor MTD estimation. For the numbers of declined patients and MTD estimation 3 + 3 is uniformly worse, with STARPAC being better in those metrics for high toxicity scenarios and TITE-CRM better with low toxicity. In situations including doses with toxicities both above and below 30%, the STARPAC design outperformed TITE-CRM with respect to every metric.ConclusionWhen considering doses with toxicities both above and below the target of 30% toxicities, the two-stage STARPAC dose escalation design provides a more efficient phase I trial design than either the traditional 3 + 3 or the TITE-CRM design. Trialists should model various designs via simulation to adopt the most efficient design for their clinical scenario.Trial registrationClinical Trials NCT03307148 (11 October 2017).

Project description:Recently, it has been reported that the relative dose intensity (RDI) of adjuvant chemotherapy (AC) influences survival in various cancers, but there are very few reports about RDI in pancreatic ductal adenocarcinoma (PDAC). The optimal timing for initiation of AC for PDAC also remains unknown. The aim of this study was to identify the significance of RDI and the time interval between surgery and initiation of AC on survival of patients with PDAC. Clinicopathological factors that affect RDI were also investigated.A total of 311 consecutive PDAC patients who underwent curative resection between May 2005 and January 2015 were enrolled. Patients who underwent neoadjuvant chemoradiation, had UICC stage IV disease, or had early recurrences within 6 months were excluded, and the remaining 168 cases were analyzed.Patients with RDIs ≥80% (n = 79) showed significantly better overall survival (OS) compared to patients with RDIs <80% (n = 55) (median survival time (MST): 45.6 months, 26.0 months, P < 0.001). Patients with no AC (n = 34) showed the worst OS (MST: 20.8 months). Whether the AC was initiated earlier or later than 8 weeks after surgery did not influence survival, either in patients with RDIs ≥80% (P = 0.79) or in those with <80% (P = 0.73). Patients in the S-1 monotherapy group (n = 49) showed significantly better OS than patients in the gemcitabine monotherapy group (n = 51) (MST: 95.0 months, 26.0 months, respectively; P = 0.001). Univariate analysis conducted after adjusting for the chemotherapeutic drug used identified several prognostic factors; male gender (P = 0.01), intraoperative blood transfusion (P = 0.005), lymph node metastasis (P = 0.03), and postoperative WBC count (P = 0.03). Multivariate analysis identified intra-plus postoperative blood transfusion (P = 0.002) and high postoperative platelet-to-lymphocyte ratios (PLR) (P = 0.04) as independent predictors of poor RDI.Efforts to maintain RDI had a greater impact on survival than the struggle to start AC early after surgery. Intra-plus postoperative blood transfusion and a high postoperative PLR could be predictive markers of reduced RDI in AC of PDAC patients. Avoidance of perioperative blood transfusions where possible and nutritional support during the perioperative period could maintain adequate RDI and may lead to improved long-term outcome.

Project description:BACKGROUND:Concomitant chemo-radiotherapy is the reference treatment for non-resectable locally-advanced Non-Small Cell Lung Cancer (NSCLC). Increasing radiotherapy total dose in the whole tumour volume has been shown to be deleterious. Functional imaging with positron emission tomography (PET/CT) offers the potential to identify smaller and biologically meaningful target volumes that could be irradiated with larger doses without compromising Organs At Risk (OAR) tolerance. This study investigated four scenarios, based on 18FDG and 18F-miso PET/CT, to delineate the target volumes and derive radiotherapy plans delivering up to 74Gy. METHOD:Twenty-one NSCLC patients, selected from a prospective phase II trial, had 18FDG- and 18F-miso PET/CT before the start of radiotherapy and 18FDG PET/CT during the radiotherapy (42Gy). The plans were based planned on a standard plan delivering 66 Gy (plan 1) and on three different boost strategies to deliver 74Gy total dose in pre-treatment 18FDG hotspot (70% of SUVmax) (plan 2), pre-treatment 18F-miso target (SUVmax?>?1.4) (plan 3) and per-treatment 18FDG residual (40% of SUVmax). (plan 4). RESULTS:The mean target volumes were 4.8 cc (± 1.1) for 18FDG hotspot, 38.9 cc (± 14.5) for 18F-miso and 36.0 cc (± 10.1) for per-treatment 18FDG. In standard plan (66 Gy), the mean dose covering 95% of the PTV (D95%) were 66.5 (± 0.33), 66.1 (± 0.32) and 66.1 (± 0.32) Gy for 18FDG hotspot, 18F-miso and per-treatment 18FDG. In scenario 2, the mean D95% was 72.5 (± 0.25) Gy in 18FDG hotspot versus 67.9 (± 0.49) and 67.9 Gy (± 0.52) in 18F-miso and per-treatment 18FDG, respectively. In scenario 3, the mean D95% was 72.2 (± 0.27) Gy to 18F-miso versus 70.4 (± 0.74) and 69.5Gy (± 0.74) for 18FDG hotspot and per-treatment 18FDG, respectively. In scenario 4, the mean D95% was 73.1 (± 0.3) Gy to 18FDG per-treatment versus 71.9 (± 0.61) and 69.8 (± 0.61) Gy for 18FDG hotspot and 18F-miso, respectively. The dose/volume constraints to OARs were matched in all scenarios. CONCLUSION:Escalated doses can be selectively planned in NSCLC target volumes delineated on 18FDG and 18F-miso PET/CT functional images. The most relevant strategy should be investigated in clinical trials. TRIAL REGISTRATION:(RTEP5, NCT01576796 , registered 15 june 2012).

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Pragmatic dose-escalation methods incorporating relative dose intensity assessment for molecularly targeted agents in phase I trials.

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Pragmatic dose-escalation methods incorporating relative dose intensity assessment for molecularly targeted agents in phase I trials.

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