A randomized, non-inferiority trial conducted by the French National Cancer Institute ( INCa ) has compared a shorter Trastuzumab ( Herceptin ) exposure of 6 months versus the standard 12 months treatment.
The PHARE trial addressed the question of duration of adjuvant treatment by Trastuzumab in HER2-positive early breast cancer.
More than 150 cancer care centers all over France participated, recruiting more than 3380 patients representative of the French population.
The trial's primary objective was to compare 6 months versus 12 months of adjuvant Trastuzumab therapy in terms of disease free-survival according to a non-inferiority schema.
The trial results are inconclusive for this non-inferiority hypothesis. Nevertheless, there is a trend in favor of 12 months treatment for the overall population.
The median follow-up in the trial was 42.5 months and at the time of the analysis 395 disease-free survival events were reported.
According to the design of this trial, which allowed for a non-inferiority hazard ratio margin of 1.15, the 6-month Trastuzumab arm ( arm B ) was not demonstrated to be significantly inferior to 12-month Trastuzumab ( arm A ), since the confidence interval contains the 1.15 non inferiority margin ( hazard ratio, HR=1.28; 95%CI: 1.04 – 1.56, p = 0.29 ).
However despite the inconclusive result in terms of non-inferiority, the hazard ratio of 1.28 suggests a trend favoring 12 months, according to the study researchers interpretation. ( Xagena )
Source: Congress of the European Society for Medical Oncology ( ESMO ), 2012