Figure 7: Survival and disease-free survival in patients grouped according to their DTH response to the third vaccine. In the ECOG study 5283, there was inadequate quality control of the vaccine specifications and a percentage of the patients received inadequate vaccines, based on the potency with respect to live tumor cell count. This inadequate potency among a group of vaccines was reflected in failure to induce a significant T-cell mediated immune response as measured by DTH. This lack of vaccine potency correlated to clinical benefit as reflected in significant differences in recurrencefree- and overall-survival.