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Fresh excitement about cancer immunotherapy: checkpoint inhibitors

21
Apr
2016

New clinical data from immunotherapy trials involving researchers from the Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust were presented at the AACR conference in New Orleans this week. Dr Claire Hastings looks at where this exciting research is headed.

Posted on 21 April, 2016 by Dr Claire Hastings

Researcher and a microscope (photo: Clare Turnbull)

Photo: Clare Turnbull

There has been a lot of interest over the past year in cancer immunotherapies — treatments that harness the body’s own immune system to destroy tumours.

Immune checkpoint inhibitors in particular have shown impressive response rates in clinical trials, and are currently regarded as the most successful class of cancer immunotherapy.

The immunotherapy star of the American Association for Cancer Research (AACR) Annual Meeting 2016 in New Orleans, Louisiana this week was nivolumab — an antibody that targets a checkpoint protein on the surface of immune cells called PD-1.

Immune checkpoints act as an ‘off-switch’ that prevent the immune system from damaging healthy cells during an immune response to infection. Cancer cells can interact with immune checkpoints such as PD-1 to avoid destruction. But by using antibodies to block this interaction, immune cells are kept active and free to kill cancerous cells.

Researchers from The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust were involved in checkpoint inhibitor clinical trials for melanoma and head and neck cancers presented at this year’s AACR meeting.

Remarkable results

Results presented on Monday from the Checkmate-069 trial showed that a whopping 69% of patients who received nivolumab in combination with ipililumab (an antibody that targets the immune checkpoint protein CTLA-4) survived more than two years.

Remarkably, 22% of the patients had no detectable tumours after receiving the combination.

Dr James Larkin, Consultant Medical Oncologist at The Royal Marsden and Reader at the ICR, was involved in the trial. Talking to the BBC, he said: "It is very encouraging to see that survival rate. It will be important in terms of working out the benefit of these treatments in the longer term, but nevertheless it's a relatively small study."

The data presented was from a trial of 142 patients: however, a much larger trial involving nearly 1,000 patients is in progress.

Nivolumab and ipililumab are approved separately for treating advanced melanoma on the NHS. The combination is being assessed by NICE, and a decision is expected in June.

'Game-changer'

New data presented this week at the conference saw the repertoire of nivolumab expand to head and neck cancer, a disease that was attributed to around 11,000 new cases and 3,300 deaths in the UK in 2012 — and cases are on the rise.

Nivolumab is now the first immunotherapy to show a survival benefit in head and neck cancer patients. The drug was shown to double the likelihood of surviving the disease – with 36% of patients alive after one year compared with 17% of patients who received docetaxyl chemotherapy.

The ICR’s Professor Kevin Harrington, who led the UK arm of the trial, said: “This new trial is a potential game changer for head and neck cancer, introducing a new drug treatment into our armoury that at last is better than standard chemotherapy.

“Once it has relapsed or spread, head and neck cancer is extremely difficult to treat, with surgery and radiotherapy often impossible. So it’s very good news for patients that these interim results indicate we now have a new treatment that works, and can significantly extend life.”

Nivolumab will now have to go through approval process of the European Medicines Agency (EMA) and NICE before it is available for head and neck cancer patients on the NHS.

More to come

Checkpoint inhibitors, including nivolumab, have been approved by the EMA for advanced melanoma and squamous non-small cell lung cancer, yet only melanoma patients can currently receive them on the NHS.

But the situation is unlikely to stay that way. With impressive trial results and multiple pharmaceutical companies fighting to get their checkpoint inhibitors to market, we shouldn’t have to wait too long before patients with different types of cancer can benefit from these therapies.

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head and neck cancer
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