Women with an aggressive form of breast cancer could live longer if treated with a combination of Tyverb (lapatinib) plus Herceptin (trastuzumab), recent trial data suggests.
The median survival time for those taking the investigational combination treatment was 14 months, compared to 9.5 months on monotherapy lapatinib.
The results of the Phase III study were presented during the 32nd Annual CTRC-AACR San Antonio Breast Cancer Symposium, held in Texas, USA.
The study included 296 women with ErbB2-positive breast cancer, which is characterised by an overexpression of the ErbB2 protein in the cancer cells. Patients enrolled in the study had experienced recurrence of breast cancer despite a median of three prior trastuzumab-based therapies.
The data presented at the San Antonio congress showed that patients overcame resistance to trastuzumab with the introduction of the lapatinib-trastuzumab combination.
“The clinical benefits brought forth by the lapatinib and trastuzumab combination are quite compelling and lead me to believe the agents may be acting together to form a sort of ‘dual blockade’ to obstruct the ErbB2 pathway necessary for the tumour to thrive,” said primary investigator Kimberly Blackwell, MD, Duke University Medical Center.
Patients in the study received either single-agent lapatinib or a combination of lapatinib and trastuzumab, though patients in the first group were able to switch to combination therapy if their disease progressed after four weeks. Women treated with monotherapy lapatinib experienced a median overall survival time of 9.5 months compared with 14 months when treated with the combination.
“It’s possible that, by lapatinib working inside the cell and trastuzumab working outside the cell, the combination of agents is able to provide a more complete anti-tumour attack,” said Blackwell. “To achieve a survival advantage of greater than one year for this aggressive form of breast cancer is very encouraging.”