Research data presented Thursday at the European Breast Cancer Conference indicate that combination treatment of Novartis' Tykerb (lapatinib) and Roche's Herceptin (trastuzumab) dramatically shrank tumours in women with HER2-positive breast cancer. Study investigators found that after 11 days of treatment with the drug combination, the remaining tumour was too small for a measurement of cell proliferation in about 25 percent of women. Study co-leader Judith Bliss stated "our results are a strong foundation on which to build further trials of combination anti-HER2 therapies prior to surgery – which could reduce the number of women who require subsequent chemotherapy, which is also very effective but can lead to long-term side effects."
In the study, 257 women with HER2-positive breast cancer with tumours measuring between 1 cm and 3 cm in size were initially randomised to receive either Tykerb, Herceptin or no treatment in the 11-day period between the initial diagnosis and surgery to remove the tumours. Halfway through the period, the investigators adjusted the study design so that additional women allocated to the Tykerb arm also received Herceptin.
The researchers observed that among the 66 women who were treated with both Tykerb and Herceptin, 17 percent displayed only minimal residual disease, defined as a residual tumour size of less than 5 mm in diameter, while an additional 11 percent experienced a pathological complete response. Conversely, 3 percent of women in the Herceptin-only group exhibited residual disease or a complete response.
Chief investigator Nigel Bundred noted "these early and significant tumour regressions seen on dual anti-HER2 therapy suggest that we will be able to personalise treatment for these cancers on the basis of early response, allowing us to identify patients who in the future may avoid treatment morbidity or avoid chemotherapy."
Commenting on the findings, Breast Cancer Now chief executive Delyth Morgan remarked "we hope this particularly impressive combination trial will serve as a stepping stone to an era of more personalised treatment for HER2 positive breast cancer," adding "such a rapid response to treatment could soon give doctors the unprecedented ability to identify women responding so well that they would not need gruelling chemotherapy."
Meanwhile, Arnie Purushotham of Cancer Research UK, which funded the study, explained "these results are very promising if they stand up in the long run and could be the starting step of finding a new way to treat HER2 positive breast cancers." Purushotham continued "this could mean some women can avoid chemotherapy after their surgery - sparing them the side-effects and giving them a better quality of life."
In March last year, Novartis gained rights to Tykerb from GlaxoSmithKline as part of an asset-swap deal that included the sale of the UK company's oncology business to the Swiss drugmaker for $16 billion in cash.
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