Herceptin Prolongs Progression Free Survival Of HER2 Breast Cancer Patients

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Main Category: Breast Cancer
Also Included In: Pharma Industry / Biotech Industry;  Clinical Trials / Drug Trials
Article Date: 30 May 2008 - 8:00 PDT

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The results of a phase III trial comparing Herceptin with chemo against chemo on its own showed that Herceptin helped women with aggressive metastatic HER2-positive breast cancer live nearly three months longer without their cancer progressing. The findings are being presented this weekend at the 44th annual meeting of the American Society for Clinical Oncology (ASCO) in Chicago.

The phase III randomized German Breast Group (GBG-26) trial was led by the Managing Director of the German Breast Group, Professor von Minckwitz of the University Women's Hospital in Frankfurt, Germany. The results are also published in a supplement to the May 20th issue of the Journal of Clinical Oncology.

"It is rewarding to see that trastuzumab [Herceptin] keeps working in women whose aggressive HER2-positive breast cancer progresses," said von Minckwitz.

The GBG-26 phase III trial's final results showed that Herceptin continued to be effective in women given additional treatment after their cancer progressed during previous Herceptin treatment.

Unfortunately, for most women with advanced breast cancer, the disease continues to spread after initial treatment and they are likely to need several more treatments of different types. So this study addressed a very important question: should Herceptin be continued beyond progression? And the results suggest, yes, it should, because it extends progression free survival.

The study's key findings showed that Herceptin with Xeloda (capecitabine) extended life without cancer progression by nearly 3 months (from 5.6 to 8.5 months) compared to Xeloda chemotherapy alone.

Another important result was that staying on Herceptin nearly doubled the proportion of patients responding to treatment from 27 to 48 per cent.

For this trial, patients with HER-2 positive, locally advanced or metastatic breast cancer that progressed during treatment with Herceptin, with or without adjuvant and/or first line metastatic chemotherapy were randomized to receive either Xeloda (2500 mg/m2 on days 1-14) on its own, or Xeloda plus continuation of Herceptin (6 mg/kg body weight every 3 weeks).

The primary end point of the trial was time to progression (TTP) and the final analysis included 156 patients.

Analysis of the results (median follow up 11.8 months) showed progression-free survival of 5.6 months with 53 events for the Xeloda-only group, and 8.5 months with 48 events for the Xeloda plus Herceptin group. Overall survival was 19.9 months with 31 events for Xeloda and 20.3 months with 26 events for Xeloda plus Herceptin.

Adverse events, but no therapy related deaths occurred.

"The GBG-26 study results confirm that trastuzumab continues to target and shrink the cancer even beyond progression when combined with another chemotherapy," said von Minckwitz.

William M Burns, CEO of the Pharmaceuticals Division of Roche, the drug company that makes Herceptin and is based in Basel, Switzerland, said:

"The GBG-26 study adds to the existing strong evidence that Herceptin extends survival throughout all stages of HER2-positive breast cancer."

"These results provide new hope for women whose breast cancer is difficult to treat," he added.

Breast cancer is the most common cancer among women worldwide. More than 1 million new cases, and more than 400,000 people die, of breast cancer every year.

In HER-2 positive breast cancer, the tumours have a much greater amount of a protein called HER-2 on the surfaces of the cancer cells. Around 20 to 30 per cent of women with breast cancer show HER-2 positive symptoms.

Herceptin is a "humanized antibody", designed to block the HER-2 protein, which is coded by a particular gene that causes cancer. Herceptin has shown effective results with both early and advanced (metastatic - where the cancer has spread to other organs) breast cancers.

On its own and with standard chemotherapy, Herceptin has shown improvements in response rates, disease-free survival and overall survival, while maintaining quality of life for women with the HER-2 form of breast cancer, said Roche in a prepared statement.

"Capecitabine vs. capecitabine + trastuzumab in patients with HER2-positive metastatic breast cancer progressing during trastuzumab treatment: The TBP phase III study (GBG 26/BIG 3-05)."
G. Von Minckwitz, C. Zielinski, E. Maarteense, P. Vogel, M. Schmidt, H. Eidtmann, T. Cufer, F. E. de Jongh, M. Kaufmann, S. Loibl.
J Clin Oncol 26: 2008 (May 20 suppl; abstr 1025).
Presented as Abstract No 1025, at 44th Annual Meeting of American Society of Clinical Oncology (ASCO), May 30th - June 3rd, 2008, Chicago.

Click here to view Abstract (ASCO).

Source: Roche press release, conference abstract.

Written by: Catharine Paddock, PhD


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