Denosumab reduces breast cancer relapse rate

Denosumab reduces breast cancer relapse rate

9 Dec 2015

Giving a monoclonal antibody (denosumab) as adjuvant therapy with aromatase inhibitors in postmenopausal, hormone-receptor-positive breast cancer patients reduces the relapse rate by 18%. This is the central finding of the ABCSG 18 breast cancer study regarding disease-free survival.

The results of the placebo-controlled, adjuvant study ABCSG 18, involving 3,425 postmenopausal breast cancer patients indicate a further important benefit of treatment with the monoclonal antibody denosumab, which was administered as an adjuvant therapy to aromatase inhibitors within the framework of the ABCSG 18 study. The results of the primary study endpoint -- the effect of denosumab on bone health -- showed that drug-related osteoporosis and bone fractures can be reduced by a remarkable 50% as a side-effect of the adjuvant therapy, without any additional toxicity.

Fewer breast cancer relapses with denosumab

The data have now been determined for an additional study endpoint, the impact of denosumab on disease-free survival. A total of 370 disease-free survival events were recorded during the four-year period, 203 of these in the placebo group and 167 in the denosumab arm. This reduction in the recurrence rate of breast cancer is barely at the statistical significance threshold.

"This result is very pleasing, because it shows that adjuvant denosumab not only halves the number of bone fractures but also reduces the rate of recurrence of breast cancer," said Michael Gnant, Head of the University Department of Surgery at MedUni Vienna, Deputy Head of the Comprehensive Cancer Center (CCC) and President of the Austrian Breast & Colorectal Cancer Study Group (ABCSG) in his assessment of the results.

A practically side-effect-free treatment

Explorative subgroup analyses indicate that some patients in particular benefit from the practically side-effect-free administration of denosumab in addition to the standard aromatase inhibitor treatment: There is a clearly significant result, especially in the case of tumors of more than 2 cm in size and early start of treatment and in tumors with a particularly high receptor density.

"This means that denosumab, which hardly has any side-effects, is generally superior to bisphosphonates as an adjuvant therapy and, in my opinion, should be offered to all postmenopausal, hormone-receptor-positive breast cancer patients." We know that bisphosphonates, which are used for treating osteoporosis, can have a positive impact upon disease-free survival. Denosumab acts in a similar way to bisphosphonates but is more effective and less toxic and can easily be given as a subcutaneous injection (60 mg subcutaneously 2x year)” Gnant commented.

Source: Science Daily