New hope for women with triple negative breast cancer

Researchers hope that three new breakthrough drugs designed to target triple negative breast cancer could potentially transform therapy for those with the hard-to-treat disease.

There are currently no targeted therapies for those with triple negative breast cancer leaving medical care reliant on traditional treatments such as chemotherapy and radiotherapy.

Now, the recent American Society for Clinical Oncology Annual Meeting has been told that new options are on the horizon that aim to target the triple-negative cancer cells directly.

A researcher involved with all three studies, Dr Jennifer Diamond of the University of Colorado Cancer Centre, says triple negative breast cancer is in need of a breakthrough treatment.

“There's really not any drug specifically approved for triple-negative breast cancer and patients and doctors have been waiting for these targeted therapies.

“Now the first ones are in the clinic. I can’t tell you how exciting this is. These drugs or ones very much like them could be game-changers for triple-negative breast cancer,” Dr Diamond says.  

The three new drugs are currently being tested in clinical trial and include:

  • IMMU-132

This drug was granted “breakthrough” status by the US Federal Drug Administration which means it has shown promising early results. IMMU-132 works in conjunction with the chemotherapy agent, irinotecan. It attaches to a particular protein (Trop2) that is found in around 80 per cent of all triple negative breast cancers and delivers the chemotherapy drug directly to the cancer cells.

Studies found the disease stabilised in 74 per cent of patients with triple negative breast cancer who were treated with IMMU-132.  After six months, the disease was stable or better in 37 per cent of patients.

  • Vantictumab

Vantictumab also targets certain proteins on the triple negative cancer cells and works by blocking signals which tell the cancer cells to grow, survive and reproduce. Around a third of patients responded to this new therapy when treated in a clinical trial.

  • Atezolizumab

This new drug works in conjunction with the chemotherapy drug, nab-paclitaxel. It works by preventing the triple negative cancer cells from hiding from the body’s own immune system meaning the body’s immune system is more effective at fighting the cancer cells.   

A clinical trial has found that the disease stabilised in around 40 per cent of patients treated with atezolizumab.

All three drugs are still being trialled, with IMMU-132 the closest to approval. However, Dr Diamond says the results so far are positive and represent a giant step forward.

"Many cancers are slow-growing and so when you see stable disease in trials, you don't know if it's due to the treatment or to the fact that the cancer was going through a more dormant period. That's not the case with triple negative breast cancer. This is a fast-growing disease and so seeing prolonged periods of stability is a very positive result," she says.

BCAC chair Libby Burgess says she’s excited to see such progress in the treatment of triple negative breast cancer.

“We have been waiting so long for a breakthrough treatment that will help those with triple negative breast cancer and at last it seems like we have something.

“Anything that will help to effectively treat this aggressive disease is going to make a huge difference to the lives of women with triple negative breast cancer,” she says.

14 June 2016

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