Roche announced Sunday final survival results from a Phase III trial demonstrating that the addition of Perjeta (pertuzumab) to Herceptin (trastuzumab) and docetaxel increased overall survival (OS) in patients with previously untreated HER2-positive metastatic breast cancer (mBC) by 15.7 months compared to Herceptin and chemotherapy. "The survival improvement...is unprecedented among studies of metastatic breast cancer," commented lead researcher Sandra Swain.
The CLEOPATRA trial included 808 patients with previously untreated HER2-positive mBC, or with HER2-positive mBC that had come back after prior therapy in the adjuvant or neoadjuvant setting. Subjects were randomised to receive the combination of Perjeta, Herceptin and docetaxel or Herceptin and chemotherapy. The trial's main goal was progression-free survival, which Roche reported was met in 2011, while secondary endpoints included OS and safety.
An interim analysis from the study announced in 2012 showed that median OS had not yet been reached for people receiving the Perjeta regimen as more than half of the patients continued to survive. The new data presented at the European Society for Medical Oncology (ESMO) congress indicated that patients receiving the Perjeta regimen lived a median of 56.5 months compared to 40.8 months for people who received Herceptin and chemotherapy. Meanwhile, no new safety signals were observed in the trial.
"The median survival of nearly five years for people who received the Perjeta regimen is 15.7 months longer than for people who received Herceptin and chemotherapy alone, a magnitude of improvement we rarely see in clinical trials in advanced cancer," remarked Sandra Horning, Roche's chief medical officer. Roche noted that the updated OS data will be submitted to regulatory authorities for inclusion in the prescribing information for the drug.
Perjeta in combination with Herceptin and docetaxel is approved in the US and the EU for patients with previously untreated HER2-positive mBC. The Perjeta regimen has also been granted accelerated approval by the FDA as a neoadjuvant treatment for HER2-positive early breast cancer. An application in this indication has also recently been submitted to the European Medicines Agency.
Javier Cortes, another researcher on the CLEOPATRA study, called the results "remarkable," suggesting that Perjeta should be the standard of care for HER2-positive breast cancer patients. Roche spokesman Edward Lang Jr. noted that currently only around half of eligible women are being treated with the drug in the US. According to Lang, Perjeta costs about $5900 a month and Herceptin about $5300 a month. The company reported Perjeta sales of 388 million Swiss francs ($407 million) in the first half of the year, with approximately $250 million of that from the US. Analysts expect the product to generate annual sales of $3.1 billion by 2018.
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