45% of women with pre-surgery early-stage HER2-positive breast cancer experienced a complete tumor reduction when given Pertuzumab and Herceptin plus chemotherapy (docetaxel) during a Phase II study evaluation, the NEOSPHERE trial. Researchers presented their finding at the CTRC-AACR San Antonio Breast Cancer Symposium (SABCS).

Pertuzumab and Herceptin plus docetaxel was considerably more effective in reducing tumors compared to just Herceptin plus docetaxel.

Professor Luca Gianni, Principal Investigator of the study and Director of Medical Oncology at the National Cancer Institute in Milan, Italy, said:

    “The findings of the NEOSPHERE study suggested that this new approach was effective for early HER2-positive breast cancer. The combination of pertuzumab and Herceptin plus chemotherapy had a substantial effect on HER2-positive breast cancer tumours after just four cycles (12 weeks)of neoadjuvant use.”

The scientists added that side effect or cardiac risks were similar for Pertuzumab and Herceptin plus docetaxel as with Herceptin plus docetaxel, which included low white blood cell count (neutropenia), elevated body temperature, and diarrhea.

Hal Barron, Head of Global Development and Chief Medical Officer at Roche, said:

    “We are committed to developing new medicines that make a difference for people living with cancer and to advancing personalized treatments. The clinical data presented today (at SABCS) add to the body of evidence that this novel targeted regimen plus chemotherapy may improve outcomes in women with HER2-positive breast cancer.”

A Phase III trial in HER2-positive adjuvant breast cancer is planned for 2011, Roche added.

The Neoadjuvant Study of Pertuzumab and Herceptin in an Early Regimen Evaluation (NEOSPHERE) study is an international, Phase II, multicenter trial that was carried out in 78 centers worldwide, not including the USA, involving 417 adult female participants, all of whom had been diagnosed with early stage HER2-positive breast cancer and had never been given Herceptin. The trial’s primary endpoint was complete tumor disappearance at time of surgery.

The following percentages had a complete tumor disappearance (pathological complete response, pCR):

  • 45,8% for Herceptin, pertuzumab and docetaxel
  • 29,0% for Herceptin and docetaxel
  • 24,0% for pertuzumab and docetaxel
  • 16,8% for Herceptin and pertuzumab

Both Pertuzumab and Herceptin are designed to block the function of HER2. HER2 is a protein caused by a potentially cancer-causing gene that exists in about 1 in every 4 breast cancer cases. The proteins Pertuzumab and Herceptin bind to different parts of the HER2 receptor, therefore increasing the likelihood of total blocking of the pathway.

A follow-up trial on women who have already undergone surgery is also planned.

Source: Roche

Written by Christian Nordqvist