Drug that starves cancer cells could be first breakthrough against brain tumours for 20 years

A drug which starves cancer cells could be the first breakthrough in brain tumour treatment for two decades, experts hope. 

Imperial College London scientists conducted tests in mice who had glioblastoma (GBM) — one of the most aggressive forms of brain cancer. 

They gave rodents an experimental drug which robbed them of arginine — a vital nutrient tumours use to grow.

Treated mice lived for around 47 days, almost twice as long (27 days) as ones left to fend for themselves. For comparison, mice given radiotherapy lived for 37 days, on average.

When the drug was combined with radiotherapy, all of the mice went into remission and lived cancer-free for around a year before being killed. 

Study author Dr Tim Crook, a consultant in medical oncology at Cromwell Hospital, said: ‘We expect our work to change treatment of GBM and become a new standard of care for this devastating disease.’

The Wanted singer Tom Parker died in March following an 18-month battle with stage four glioblastoma. 

He said after his diagnosis that he was ‘shocked’ at the limited treatment options for GBM and ‘massive improvements’ were needed.

The cancer, which strikes around 2,000 people in England and 12,000 Americans a year, is still treated in the same way it was in the early 2000s.

The Wanted singer Tom Parker has died aged 33 after an 18-month battle with deadly and aggressive brain cancer glioblastoma

Diagnosed patients usually undergo surgery to remove as much of the tumour as possible.

This is followed by daily radiation and chemo drugs for around six weeks, after which the drugs are scaled back.

Radiation can be used to destroy additional tumour cells and treat those who are not well enough for surgery. 

The cancer is one of the most aggressive brain tumours and can double in size in just seven weeks. For comparison, the fastest-growing lung cancers take 14 weeks to double.

Some people may go into remission with GBM — where symptoms ease or disappear for a time. But the cancer often regrows.  

Arginine encourages cancerous cells to grow.

It is also used by cells which suppress the immune system — suppressor cells, which stifle disease-fighting T cells before they have a chance to act. 

For this exact reason, Dr Crook and his team believed targeting arginine would stop glioblastoma tumours growing. 

Five mice with GBM were given a weekly injection of ADI-PEG20 — an enzyme which breaks down arginine in the body. They also received a weekly dose of radiotherapy for four weeks.

Another group of the exact same size were given just the injection, while some only had radiotherapy. 

A fourth group of five mice acted as a control group, receiving no treatment at all.

As thought, reducing arginine levels weakened the effects of suppressor cells and gave the mice’s T cells a boost. 

The treatment — ADI-PEG20 coupled with radiotherapy — triggered no significant side effects and cured the mice of their tumours. None of the mice in the other groups went into remission, the researchers said.

The findings, in the Journal of Clinical Investigation, suggests depriving tumours of arginine could be a new anti-cancer strategy.

The researchers will now explore further studies using ADI-PEG20 on a different set of GBM tumours.

If these trials are successful, it means all patients with the aggressive cancer could be treated with the drug, they said.

The team hopes to trial the drug in humans to find out if it works as well. 

Dr Nel Syed, who led the trial, said the lab results showed the drug, when combined with radiotherapy, boosted cancer response and increased the lifespan of the mice.

Hugh Adams, head of stakeholder relations at Brain Tumour Research, which funded the research, said: ‘This is a significant and exciting finding. 

‘There is an urgent need for novel approaches to treat GBM which, in the majority of cases, is fatal. 

‘There have been no improvements to treatment options for this type of tumour in two decades.’