Devita, Hellman, and Rosenberg's Cancer

LWBK1006-16 LWW-Govindan-Review December 12, 2011 18:55

194 DeVita, Hellman, and Rosenberg’s CANCER: Principles and Practice of Oncology Review

way to identify and eliminate this bias in the context of the trial, so the

intention-to-treat analysis includes all consenting, randomized patients in

the study arm to which they were randomized.

Answer 16.19. The answer is D.

For Phase III trials, it is mandatory to have an independent data-safety

committee that has the power to recommend termination of the study

based on safety concerns, outstanding benefit, or futility. Because the study

leaders have a conflict of interest with respect to the decision to continue

the study, they are not part of the committee.

Answer 16.20. The answer is C.

Even if survival data have no censoring, a survival curve still provides a

better approach for data summary because it takes the length of follow-up

time into consideration. In addition, survival times are usually skewed to

the right, and the conventional means and standard deviations may not

be adequate for data description.

Answer 16.21. The answer is B.

For this study, noninformative censoring means that the probability dis-

tributions of cancer-specific survival are similar for both censored and

noncensored patients. However, patients who have experienced disease

progression are more likely to have a poor prognosis.

Answer 16.22. The answer is B.

Phase 0 trials are first in human trials that help eliminate ineffective and

toxic drugs at a very early stage of clinical development. A small sample

of patients receive a onetime low dose of the study drug at which it is

not expected to cause toxic adverse effects. These trials provide prelimi-

nary pharmacokinetic and pharmcodynamic information that enable the

go/no-go decisions on further evaluation of the study drug. These studies

do require the prior development of an assay to measure the pharmaco-

dynamic end point for the study drug.

Answer 16.23. The answer is B.

In a 2009 review of the ClinicalTrials.gov website, response rate was the

most frequent (37%) end point in Phase II clinical trials. Universities were

listed as the sponsor for 45% of all clinical trials. Only 7% of all clinical

trials utilized biomarker testing for patient selection.

Answer 16.24. The answer is B.

Meta-analysis allows for combining and summarizing the results from

several therapeutic trials. To achieve meaningful results and avoid bias,

meta-analysis includes only randomized clinical trials including unpub-

lished studies. Studies are not restricted to any particular geographic

region. Furthermore, access to individual patient data and collaboration

of the individual study investigators is required for meta-analysis.