Rob and Tanya Ritchie want to raise £5 million — an unprecedented sum for an area that receives a small fraction of that invested in other cancers.
Their son Toby was diagnosed aged five with a slow-growing tumour “the size of a golf ball” on his brain stem, which connects to the spinal cord and controls motor skills and breathing.
About 500 children a year in the UK are diagnosed with brain tumours but treatments — a combination of radiotherapy, chemotherapy and neurosurgery — have not changed for decades.
Toby, now 10, has had chemotherapy and two rounds of life-threatening surgery but the location of the tumour means it cannot be entirely removed.
In 2015 Mr Ritchie led a challenge to ski 8,848 metres — the height of Everest — uphill in the Alps in four days, raising £3 million from friends and colleagues at Goldman Sachs, where he worked.
Next month Mrs Ritchie will lead a 30-strong team, including Mr Ritchie and many of her friends, on the second Everest In The Alps expedition, in a bid to raise a further £2 million.
The “Everest” element reflects the mountain Toby has to climb in relation to the disease.
The couple’s efforts have enabled the Brain Tumour Charity to set up a research centre, drawing on expertise at Great Ormond Street Hospital and Queen Mary University of London.
In one initiative, the Everest Centre, led by Dr David Jones, hopes to launch international trials on “repurposing” adult drugs for melanoma and bowel cancer for children.
Toby’s diagnosis in 2013 was followed by 18 months of chemotherapy. This slowed the tumour but it continued to grow.
He became confused at school, his balance got worse and one of his eyes began to close.
Last year Toby, who has two elder brothers, underwent a seven-hour operation to de-bulk the tumour.
Mr Ritchie, 44, co-head of HSBC’s global banking business in the UK, said: “That was a very dramatic operation when they took out just over half of the tumour, next to his brain stem.
"It’s a very complicated place and he needed to learn to walk again.
“All the things that mattered most have improved, however — his balance may be worse but his eye is open again. His breathing is also better.
"By and large he has done brilliantly although he gets frustrated when he can’t play sport as his friends can.”
Dr Jones said there was a lack of knowledge about how best to treat the tumours but that the funding “changes the scope of what we can aim for”.
He said: “Previously it was not realistic to think you could apply for this sort of money for low-grade brain tumour research.
“It was something not seen as ‘sexy’ when you have other tumours that children are dying from very quickly.
"But if you think of the longer-term, terrible effects that children and their families have to suffer, this is one of the areas that the research can have a massive impact.”