Clinical Trial Clarification - 1263833

sawyer6
Posts:45

I have been looking through the abstracts posted ahead of the ASCO conference at the end of the month and have been wondering what definition is typically used for overall survival. The FDA website (to paraphrase) says that overall survival is from the date at which randomization began. To me this means survival from the date the investigational therapy was started, i.e. if therapy began on 1/1/14 and you lived until 1/1/15 overall survival would be 1 year, even if you might have been diagnosed with disease being studied 10 years previously and had received 5 previous treatments, for example, in those 10 years. Is my understanding correct? Thanks,

Seth

Forums
Full Archive

Reply # - May 16, 2014, 04:07 PM

JimC
Posts: 2753

Hi Seth,

That's correct. And that's why you really can't compare the survival results from one trial to another, because the starting points for each may be quite different, not to mention that the trial cohorts can be very different as well.

JimC
Forum moderator

Reply # - May 16, 2014, 04:21 PM

sawyer6
Posts: 45

Thanks Jim.

Well, that's encouraging, although I know Dr. West posted previously to proceed with caution when looking at early stage clinical trials as the response rates will likely trend downward as the number of patients enrolled increases. So, that tempers my excitement a bit with some of the numbers I saw.

Best,

Seth

Reply # - May 16, 2014, 07:36 PM

Dr West
Posts: 4735

Yes. The key is to just interpret results relative to comparable patients - within limits. So you can compare overall survival results obtained in various second line NSCLC trials to each other, which is far more appropriate than comparing results of a second line therapy trial to one of first lime treatment. However, some second line trials may enroll more fit, younger patients or more who responded well to first line treatment than another trial, so "cross trial comparisons" must be taken with a grain of salt, since they are not treating the exact same patients under the same conditions.

-Dr. West

Previous PostNext Post