endpoints for immunotherapy

One interesting article regarding” Assessing oncologic benefit in clinical trials of immunotherapy agents”,


The finding below confirming a post by Southoz regarding why PFS is not efficient end-point for immunotherapy.

According to article the reasons are :-
“The initial appearance of progressive disease may occur during immunologic therapy for at least two reasons. First, immunotherapy may induce lymphocytic tumor infiltration and inflammation of the tumor, and the associated increase in tumor diameter scored as progression on radiographic imaging (i.e. ‘tumor flare’).

Second, the appearance of new lesions or growth of primary lesions may occur after immunotherapy has been administered, since the process of immune activation is complex and delayed. During this period of activation, the tumor may be able to transiently grow even when effective therapy is priming an immune system versus tumor response.”

http://annonc.oxfordjournals.org/content/early/2010/03/16/annonc.mdq048.full


Another advantage for Overall survival over PFS is listed
below:-

" many trails who had positive PFS failed to improve overall survival. it is possible that the detected PFS difference is not a true finding. Unlike with OS, in which the date of death is exact, the date of progression is subject to measurement error and other forms of bias. Differences in the timing of measurement between arms of randomized trials (resulting, for example, from differing cycle lengths) may result in an artifactual difference in progression dates."

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