  The landscape of dose-finding designs for phase I clinical trials is rapidly
shifting in the recent years, noticeably marked by the emergence of
interval-based designs. We categorize them as the iDesigns and the IB-Designs.
The iDesigns are originated by the toxicity probability inter- val (TPI)
designs and its two modifications, the mTPI and mTPI-2 designs. The IB-Designs
started as the cumulative cohort design (CCD) and is recently extended by the
BOIN design. We discuss the differences and similarities between these two
classes of interval-based designs, and compare their simulation performance
with popular non-interval designs, such as the CRM and 3+3 designs. We also
show that in addition to the population-level operating characteristics from
simulated trials, investigators should also assess the dose-finding decision
tables from the implemented designs to better understand the per-trial and
per-patient behavior. This is particularly important for nonstatisticians to
assess the designs with transparency. We pro- vide, to our knowledge, the most
comprehensive simulation-based comparative study on various interval-based
dose-finding designs.
