Optimal biological dose: a systematic review in cancer phase I clinical trials.

BACKGROUND: Classical phase 1 dose-finding designs based on a single toxicity endpoint to assess the maximum tolerated dose were initially developed in the context of cytotoxic drugs. With the emergence of molecular targeted agents and immunotherapies, the concept of optimal biological dose (OBD) was subsequently introduced to account for efficacy in addition to toxicity. The objective was therefore to provide an overview of published phase 1 cancer clinical trials relying on the concept of OBD. METHODS: We performed a systematic review through a computerized search of the MEDLINE database to identify early phase cancer clinical trials that relied on OBD. Relevant publications were selected based on a two-step process by two independent readers. Relevant information (phase, type of therapeutic agents, objectives, endpoints and dose-finding design) were collected. RESULTS: We retrieved 37 articles. OBD was clearly mentioned as a trial objective (primary or secondary) for 22 articles and was traditionally defined as the smallest dose maximizing an efficacy criterion such as biological target: biological response, immune cells count for immunotherapies, or biological cell count for targeted therapies. Most trials considered a binary toxicity endpoint defined in terms of the proportion of patients who experienced a dose-limiting toxicity. Only two articles relied on an adaptive dose escalation design. CONCLUSIONS: In practice, OBD should be a primary objective for the assessment of the recommended phase 2 dose (RP2D) for a targeted therapy or immunotherapy phase I cancer trial. Dose escalation designs have to be adapted accordingly to account for both efficacy and toxicity.

GUIP1: a R package for dose escalation strategies in phase I cancer clinical trials.

BACKGROUND: The main objective of phase I cancer clinical trials is to identify the maximum tolerated dose, usually defined as the highest dose associated with an acceptable level of severe toxicity during the first cycle of treatment. Several dose-escalation designs based on mathematical modeling of the dose-toxicity relationship have been developed. The main ones are: the continual reassessment method (CRM), the escalation with overdose control (EWOC) method and, for late-onset and cumulative toxicities, the time-to-event continual reassessment method (TITE-CRM) and the time-to-event escalation with overdose control (TITE-EWOC) methods. The objective of this work was to perform a user-friendly R package that combines the latter model-guided adaptive designs. RESULTS: GUIP1 is an R Graphical User Interface for dose escalation strategies in Phase 1 cancer clinical trials. It implements the CRM (based on Bayesian or maximum likelihood estimation), EWOC and TITE-CRM methods using the dfcrm and bcrm R packages, while the TITE-EWOC method has been specifically developed. The program is built using the TCL/TK programming language, which can be compiled via R software libraries (tcltk, tkrplot, tcltk2). GUIP1 offers the possibility of simulating and/or conducting and managing phase I clinical trials in real-time using file management options with automatic backup of study and/or simulation results. CONCLUSIONS: GUIP1 is implemented using the software R, which is widely used by statisticians in oncology. This package simplifies the use of the main model-based dose escalation methods and is designed to be fairly simple for beginners in R. Furthermore, it offers multiple possibilities such as a full traceability of the study. By including multiple innovative adaptive methods in a free and user-friendly program, we hope that GUIP1 will promote and facilitate their use in designing future phase I cancer clinical trials.

Contrast-enhanced intra-operative ultrasound as a clinical decision making tool during surgery for colorectal liver metastases: The ULIIS study.

BACKGROUND: Detecting more colorectal liver metastases (CRLMs) during surgery may help optimise strategy and improve outcomes. Our objective was to determine clinical utility (CU) of contrast-enhanced intra-operative ultrasound (CE-IOUS) using sulphur hexafluoride microbubbles during CRLM surgery. METHOD: A prospective phase II trial performed at two comprehensive cancer research centres. Patients operated for CRLMs were eligible and assessable if intra-operative ultrasound (IOUS) and CE-IOUS had been performed and pathological results were available and/or 3-month imaging. CU was defined as the justified change in planned surgical strategy or procedure using CE-IOUS. RESULTS: Out of the 68 patients enrolled, 54 were eligible and assessable. 43 patients underwent pre-operative chemotherapy. The median number of CRLMs was 2 (range, 1-11). Pre-operative staging was performed using MRI. IOUS allowed identification of 45 new CRLMs in 13 (24.7%) patients. Compared to IOUS, CE-IOUS allowed identification of 10 additional CRLMs in 9 (16.7%) patients. Surgery was altered and justified in 4 patients only, leading to a CU rate of 7.70% (95 CI, [3.2, 18.6]). No missing CRLMs were identified by CE-IOUS. CONCLUSIONS: Although the primary endpoint was not met for one protocol violation, secondary endpoints indicate that CE-IOUS has an intermediate added-value for surgeons treating CRLMs. TRIAL REGISTRATION: NCT01880554 (https://clinicaltrials.gov/).