Isaac was first offered an NHS clinical trial at The Royal Marsden in Sutton, Surrey, which was tailored to the results of his genome sequencing.
Genome sequencing is the laboratory technique used to determine the sequence of nucleotides or bases in a DNA molecule.
According to Harriet, “for a few months, it appeared to be working, with Isaac’s tumour shrinking by 40%”.
“Sadly, a few months into the trial, Isaac became unwell and deteriorated very quickly.
“The tumour had spread to his spine, and he was no longer able to travel to Germany for immunotherapy.”
She described how “devastating” it was to see her brother’s hopes and dreams of getting married to his childhood sweetheart and starting a family slip away, following the deterioration.
Harriet said: “Being told there is nothing more they can do is the worst thing you can possibly hear.
“You feel helpless, especially for my parents – when you have a child and if they have an issue, you just want to solve it, and being told there is nothing you can do, is the worst.”