New drug-chemo combo offers promise for aggressive breast cancers

Washington, July 19 (ANI): Researchers at Melbourne's Walter and Eliza Hall Institute have found that combining a new class of anti-cancer agent with conventional chemotherapy offers improved results for some of the most aggressive breast cancer.

ABT-737 is one of a new class of anti-cancer agents called BH3 mimetics that target and neutralise the so-called Bcl-2 proteins in cancer cells. Bcl-2 proteins act to 'protect' the cells after they have been damaged by chemotherapy drugs, and prevent the cancer cells from dying.

Professor Geoff Lindeman and his colleagues said that the BH3 mimetics showed promise for treating breast cancers, including 'triple negative' cancers.

Around 20 percent of breast cancers are known as 'triple negative' cancers, which test negative for oestrogen, progesterone and HER2 receptors, and are notoriously hard to tackle with regular anti-cancer treatments or trastuzumab.

Dr Lindeman said that early results suggest navitoclax (an orally-available BH3 mimetic) could provide new hope for treating some breast cancers that are not candidates for other currently available treatments.

"ABT-737 targets proteins from the Bcl-2 family, which are found at high levels in up to 70 per cent of breast cancers," Dr Lindeman said.

"We have shown that breast tumours that have high levels of Bcl-2 respond well to treatment with ABT-737 when used in combination with a conventional chemotherapy drug," he added.

Co-author Jane Visvader said combined treatment with ABT-737 and docetaxel (a commonly used chemotherapy drug for treating breast cancer) in mice transplanted with human breast cancer cells improved tumour response and survival rates, when compared to docetaxel as a single agent.

ABT-737 alone was not effective in treating cancers with high levels of Bcl-2, nor was it effective in treating cancers that did not express Bcl-2.

"The research suggests that these agents make the cancer cells more vulnerable to chemotherapy," Dr Visvader said.

"We are particularly excited that the research shows a good response in Bcl-2-expressing breast cancer, including basal-like breast cancer, which is often the most aggressive and hardest to treat," she added.

The finding is published in the current issue of the Proceedings of the National Academy of Sciences USA. (ANI)