A drug that starves cancer cells could be the first breakthrough in treating brain tumors in two decades, experts hope.
Imperial College London Scientists conducted tests in mice that had glioblastoma (GBM) – one of the most aggressive forms of brain cancer.
They gave the rodents an experimental drug that robbed them of arginine – an important nutrient used to keep tumors from growing.
Treated mice lived for about 47 days, almost twice as long (27 days) as those left to fend for themselves. For comparison, mice given radiotherapy live an average of 37 days.
When the drug was combined with radiotherapy, all the mice relapsed and remained cancer-free for about a year before being killed.
Study author Dr Tim Crook, a consultant in medical oncology at Cromwell Hospital, said: ‘We hope that our work will transform the treatment of GBM and become a new standard of care for this devastating disease.’
Wanted singer Tom Parker died in March after 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 that ‘massive correction’ was needed.
Cancer, which affects about 2,000 people in England and 12,000 Americans a year, is still treated the same way it was in the early 2000s.
A team from Imperial College London conducted clinical trials in mice that had glioblastoma (GBM) – one of the most aggressive forms of brain cancer. They gave mice a drug that reduced levels of arginine – an important nutrient that tumors use to grow. Image: Tumor cells derived from glioblastoma multiforme
Wanted singer Tom Parker has died at the age of 33 after an 18-month battle with the deadly and aggressive brain cancer glioblastoma
Diagnosed patients usually undergo surgery to remove as much of the tumor as possible.
This is followed by daily radiation and chemo drugs for about six weeks, after which the drugs are scaled back.
Radiation may be used to destroy excess tumor cells and to treat those that are not large enough for surgery.
Cancer is one of the most aggressive brain tumors and can double in size in just seven weeks. For comparison, the fastest growing lung cancer takes 14 weeks to double.
Some people with GBM can go into remission – where symptoms subside or disappear for a period of time. But the cancer often regresses.
Arginine encourages cancer cells to grow.
It is also used by cells that suppress the immune system – suppressor cells, which suppress disease-fighting T cells before they have a chance to act.
For this exact reason, the team led by Dr. Nelofer Syed believed that targeting arginine would stop glioblastoma tumors from growing.
Five mice with GBM were given weekly injections of ADI-PEG20 – an enzyme that breaks down arginine in the body. He also received a weekly dose of radiotherapy for four weeks.
Another group of the exact same size was given just injections, while some had only radiotherapy.
A fourth group of five rats served as a control group, which received no treatment.
As thought, reducing arginine levels weakened the effects of the suppressor cells and boosted the T cells of the mice.
The treatment – combined with ADI-PEG20 radiotherapy – caused no significant side effects and cured the mice of their tumors. None of the rats in the other groups went into remission, the researchers said.
in the conclusion Journal of Clinical Investigationsuggests that depriving tumors of arginine may be a new anti-cancer strategy.
The researchers will now explore further studies using ADI-PEG20 on a different set of GBM tumors.
If these trials are successful, it means that all patients with aggressive cancer can be treated with the drug, he said.
The team hopes to test the drug in humans to find out if it even works.
Dr Nel Syed, who led the trial, said laboratory results showed that when combined with radiotherapy, the cancer response was boosted and the mice’s lifespan increased.
Hugh Adams, Head of Stakeholder Relations in Brain Tumor Research, which funded the research, said: ‘This is an important and exciting discovery.
‘There is an urgent need for new methods to treat GBM, which is fatal in most cases.
‘There has been no improvement in the treatment options for this type of tumor in two decades.’