The addition of pertuzumab to trastuzumab and docetaxel prolonged OS by nearly 16 months in patients with HER-2–positive metastatic breast cancer, according to final OS results of the CLEOPATRA study presented at the European Society for Medical Oncology Annual Congress in Madrid.
“The results of the CLEOPATRA study suggest that all patients who have newly diagnosed metastatic or advanced HER-2–positive breast cancer should be given the opportunity to have treatment with dual antibody therapy with trastuzumab and pertuzumab with chemotherapy,” Sandra M. Swain, MD, FACP, medical director of Washington Cancer Institute of the MedStar Washington Hospital Center, told HemOnc Today. “These results are phenomenal. We have not seen these kind of survival results in the metastatic disease setting in the past. The other very important aspect is that this could predict a mortality reduction in the adjuvant setting which will be reported in the APHINITY trial sometime in the next couple of years.”
Sandra M. Swain
Swain and colleagues evaluated data from 808 patients assigned to receive trastuzumab (Herceptin, Genentech) and docetaxel with either pertuzumab (Perjeta, Genentech) or placebo.
An interim analysis presented in May 2012 showed the addition of pertuzumab extended OS compared with trastuzumab and docetaxel alone; however, median OS had not yet been reached in the intervention arm (HR=0.66; 95% CI, 0.52-0.84).
The final OS analysis was planned after 385 deaths had occurred in the study population. Median follow-up at this time was 50 months.
Median OS was 56.5 months in the pertuzumab arm vs. 40.8 months in the placebo arm (HR=0.68; 95% CI, 0.56-0.84).
These data include 48 patients who had crossed over to treatment with pertuzumab from the placebo arm after the interim OS analysis.
“The survival improvement of nearly 16 months observed in CLEOPATRA is unprecedented among studies of metastatic breast cancer,” Swain said in a press release. “This is the kind of survival improvement for which we have worked, and this data will be incredibly meaningful to patients and their families.”
Researchers observed the survival benefit associated with pertuzumab in all subgroup analyses.
Adverse events that occurred in the pertuzumab arm were consistent with those that had been previously reported, and long-term cardiac safety was maintained in this arm, researchers wrote.
“This is one of the biggest steps toward making this disease a chronic condition in the near future,” researcher Javier Cortes, MD, PhD, director of the Breast Cancer Program at Vall d’Hebron Institute of Oncology in Barcelona, Spain, said in the press release. “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 OS 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.”
For more information:
Swain SM. Abstract #3500_PR. Presented at: European Society for Medical Oncology Annual Congress; Sept. 26-30, 2014; Madrid, Spain.
Disclosure: Swain reports an uncompensated consultant role with Genentech/Roche, and funding for her institution from Bristol-Myers Squibb, Genentech/Roche, Pfizer, Puma and Sanofi-Aventis. Cortes reports consultant roles with and honoraria from Celgene, Eisai, Novartis and Roche. See the abstract for a list of the other researchers’ relevant financial disclosures.