Authors: Georgia Patey, Future Science Group
Updated results from the CLEOPATRA study reveal that patients with HER2-positive breast cancer that has spread to other parts of the body live approximately 16 months longer if treated with a combination of pertuzumab, trastuzumab and chemotherapy compared with those treated with trastuzumab and chemotherapy alone.
The pivotal Phase III CLEOPATRA study evaluated the safety and efficacy of pertuzumab, trastuzumab and chemotherapy in 808 patients with previously untreated HER2-positive metastatic breast cancer, one of the most aggressive forms of the disease.
“In CLEOPATRA we evaluated whether dual HER2 blockade by combining the antibody pertuzumab with trastuzumab and chemotherapy would help people live longer (overall survival; OS) or live longer without their disease worsening (progression-free survival; PFS),” explained lead author Sandra Swain from Medstar Washington Hospital Center (Washington DC, USA). The study authors had previously reported that the pertuzumab regimen significantly extended PFS and OS, and the new data reports the results of the final analysis of survival after a median of 50 months follow-up.
The new results were presented at the 2014 European Society for Medical Oncology Congress (26–30 September 2014, Madrid, Spain), and show that individuals treated with the pertuzumab combination lived 15.7 months longer than those who received trastuzumab and chemotherapy alone (median OS: 56.5 vs 40.8 months, respectively).
“The survival improvement of nearly 16 months observed in CLEOPATRA is unprecedented among studies of metastatic breast cancer,” commented Swain. Furthermore, the results are likely to be conservative, as OS was analyzed using all randomized patients, with no adjustments for cross-over once the study treatments were unblinded. Patients who crossed over to the pertuzumab arm from placebo were analyzed as part of the placebo arm: “As such, this is a very conservative final analysis of survival,” Swain commented.
The OS benefit witnessed was consistent across all patient subgroups, and the previously observed benefit in PFS was maintained after long-term follow-up. In addition, the long-term safety profile of the combination regimen was unchanged from previous analyses and the long-term cardiac safety profile was maintained. “This is the kind of survival improvement for which we have worked, and this data will be incredibly meaningful to patients and their families,” Swain remarked.
Javier Cortes, Director of the Breast Cancer Program at Vall D’Hebron Institute of Oncology (Barcelona, Spain), another author of the study, commented: “We should consider this combination as the standard of care for our patients … I can see no reason to justify the use of trastuzumab without pertuzumab. The impressive overall survival data we have observed at ESMO 2014 will help us, as physicians, to continue working; it will help patients, to fight against their disease; and it will help society to understand that people will not die of cancer in the future.”
Source: ESMO 2014 Press Release