People with HER-2 positive metastatic breast cancer (mBC) lived significantly longer (overall survival) when treated with the combination of Perjeta (pertuzumab), Herceptin (trastuzumab) and docetaxel chemotherapy, compared to Herceptin and docetaxel chemotherapy alone in the phase III CLEOPATRA study. Roche will be submitting this data for presentation at an upcoming medical meeting.

“We are pleased that Perjeta helped people with HER2-positive metastatic breast cancer live longer and lengthened the time they lived without their disease worsening,” said Hal Barron, MD, chief medical officer and Head, Global Product Development.  “The improvement in survival seen in the CLEOPATRA study is great news for patients and doctors, and reinforces our belief that Perjeta will improve the outlook for people with this devastating disease.”

Perjeta is a personalised medicine that targets the HER2 receptor, a protein found in high quantities on the outside of cancer cells in HER2-positive cancers. Perjeta is believed to work in a way that is complementary to Herceptin, as the two medicines target different places on the HER2 receptor.

The FDA recently approved Perjeta in combination with Herceptin and docetaxel chemotherapy for the treatment of people with HER2-positive mBC who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease, based on the results of the CLEOPATRA study. Roche has also submitted a Marketing Authorisation Application to the European Medicines Agency (EMA) for Perjeta for people with previously untreated HER2-positive mBC.

This analysis of overall survival in the CLEOPATRA study crossed the pre-specified boundary showing that the combination of Perjeta, Herceptin and docetaxel chemotherapy significantly improved overall survival in people with HER2-positive mBC, compared with Herceptin and chemotherapy.  Overall survival is a secondary endpoint of the CLEOPATRA study.

The final progression free survival (PFS, the primary endpoint) and safety profile data from the CLEOPATRA study were published in December 2011 in the New England Journal of Medicine and demonstrated that people who received Perjeta in combination with Herceptin and docetaxel chemotherapy had a statistically significant 38 percent reduction in the risk of their disease worsening or death (progression-free survival; PFS, HR=0.62, p-value=<0.0001) compared to people who received Herceptin and chemotherapy plus placebo. The median PFS improved by 6.1 months from 12.4 months for people who received Herceptin and chemotherapy  plus placebo to 18.5 months for those who received Perjeta, Herceptin and chemotherapy.

In CLEOPATRA, the most common adverse reactions (rate greater than 30 percent) seen with Perjeta in combination with Herceptin and docetaxel chemotherapy were diarrhoea, hair loss, low white blood cell count with or without fever, upset stomach, fatigue, rash and peripheral neuropathy (numbness, tingling or damage to the nerves). The most common Grade 3–4 adverse reactions (rate greater than two per cent) were low white blood cell count with or without fever, decrease in a certain type of white blood cell, diarrhoea, damage to the nerves, decrease in red blood cell count, weakness and fatigue.

CLEOPATRA (CLinical Evaluation Of Pertuzumab And TRAstuzumab) is an international, phase III, randomised, double-blind, placebo-controlled study. The study evaluated the efficacy and safety profile of Perjeta combined with Herceptin and docetaxel chemotherapy compared to Herceptin and chemotherapy plus placebo in 808 people with previously untreated HER2-positive mBC or with HER2-positive mBC that that had recurred after prior therapy in the adjuvant or neo-adjuvant setting.

The primary endpoint of the study was PFS as assessed by an independent review committee. Secondary endpoints were overall survival, PFS by investigator assessment, safety profile, overall response rate (ORR), duration of response and time to symptom progression.

Perjeta is designed specifically to prevent the HER2 receptor from pairing (or ‘dimerising’) with other HER receptors (EGFR/HER1, HER3 and HER4) on the surface of cells, a process that is believed to play a role in tumour growth and survival. Binding of Perjeta to HER2 may also signal the body’s immune system to destroy the cancer cells. The mechanisms of action of Perjeta and Herceptin are believed to complement each other, as both bind to the HER2 receptor, but to different places. The combination of Perjeta, Herceptin and docetaxel chemotherapy is thought to provide a more comprehensive blockade of HER signalling pathways.

Breast cancer is the most common cancer among women worldwide. In HER2-positive breast cancer, increased quantities of the human epidermal growth factor receptor 2 (HER2) are present on the surface of the tumour cells. This is known as “HER2 positivity” and affects approximately 15-20 per cent of women with breast cancer HER2-positive cancer is a particularly aggressive form of breast cancer.

Herceptin (trastuzumab) is a humanised monoclonal antibody, designed to target and block the function of HER2, a protein produced by a specific gene with cancer-causing potential when it is overexpressed. The mode of action of Herceptin is unique in that it activates the body’s immune system and suppresses HER2 signalling to target and destroy the tumour. Herceptin has demonstrated unprecedented efficacy in treating both early and advanced (metastatic) HER2-positive breast cancer. Given on its own as monotherapy as well as in combination with or following standard chemotherapy, Herceptin has been shown to improve overall survival, response rates and disease-free survival while maintaining quality of life in women with HER2-positive breast cancer. Herceptin is marketed in the United States by Genentech, in Japan by Chugai and internationally by Roche.