Offered that vemurafenib and ipilimumab are at present acce

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Offered that vemurafenib and ipilimumab are at present acce

Post  wangqian on Wed Nov 19, 2014 10:04 am

An indirect comparison of RADIANT 3 and A6181111 without adjustment for baseline differences, based only on comparing HRs across trials, would have been topic to confounding by observed baseline differences in between tri als. In advance of matching, notable distinctions had been observed in efficiency status [You must be registered and logged in to see this link.] and prior treatments. These along with other baseline distinctions could have impacted PFS and OS out comes, even if measured as HRs. Such as, HRs for that impact of everolimus versus placebo on PFS ranged from 0. 21 to 0. 47 across patient subgroups reported for RADIANT three and HRs for PFS with sunitinib versus placebo ranged from 0. 22 to 0. 75 across subgroups re ported for A6181111. Because baseline traits modify HRs, they could confound a cross trial comparison of HRs.

It must be mentioned that statistical significance of HR modification or of baseline variations is not really needed for significant confounding to arise. By balancing [You must be registered and logged in to see this link.] ob served baseline characteristics across trials, the matching adjustment applied during the current examine decreases the po tential for observed characteristics to bias the cross trial comparison of outcomes, even though they do modify HRs rela tive to placebo. Matching adjustment was also applied in the existing study to examine OS outcomes concerning active therap ies, and concerning everolimus as well as placebo arm while in the sunitinib trial. In these comparisons, relative result mea sures for instance the HR couldn't be employed as a result of cross overs on the placebo arms of the two trials.

On the other hand, it was attainable to assess outcomes among trial populations that had been balanced for all observed baseline characteris tics, and also to test the balance by evaluating placebo arm PFS [You must be registered and logged in to see this link.] between trials. Matching adjusted indirect compari sons versus external trial data might be viewed as an adjusted strategy to comparisons towards historical controls, which have a prolonged history in oncology. This review has many limitations. Most significantly, while this review employed information from randomized managed trials, the cross trial comparisons are akin to observational studies, and also have comparable limitations. In particular, as in any observational examine, distinctions in unobserved pa tient qualities or other systematic distinctions be tween trials could confound cross trial comparisons of outcomes, in spite of matching around the observed characteris tics.

A connected limitation is that the current research could only modify for baseline qualities that had been avail able for both trials. There have been also post randomization differences in scheduled imaging assessments to detect disease progression. The influence of those variations is constrained since comparisons were based mostly on hazard ra tios relative to placebo. The energetic and placebo arms shared the same imaging protocol inside of every single trial. Comparisons of OS were not right impacted by vary ences in imaging schedules. After adjusting for accessible traits, residual imbalance in placebo arm PFS, however not statistically major, recommended prolonged PFS for placebo A6181111 versus placebo in RADIANT three. A considerable head to head randomized trial of everolimus versus sunitinib can be necessary to compare outcomes with no the possible for unobserved confounding.

wangqian

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