Caitlin Leggett was diagnosed with acute myeloid leukaemia in April 2025 (Image: PA Real Life)
A 24-year-old twin given just six months to live after her leukaemia returned is attempting to raise £500,000 for potentially life-saving treatment abroad, saying the prospect of leaving her identical sister behind is “unthinkable”. Caitlin Leggett, from Cardiff, was diagnosed with acute myeloid leukaemia – an aggressive cancer of the white blood cells – in April 2025, with a persistent rash being the only indication that something was seriously wrong.
A 24-year-old woman from Cardiff, facing a terminal leukaemia diagnosis, is striving to gather £500,000 to fund potentially life-saving treatment abroad. Caitlin Leggett, whose cancer has returned, finds the idea of leaving her twin sister behind “unthinkable.” Diagnosed with acute myeloid leukaemia—an aggressive white blood cell cancer—in April 2025, Caitlin only became aware of her condition due to a persistent rash.
After enduring rigorous chemotherapy sessions and undergoing a stem cell transplant in December 2025, Caitlin initially entered complete remission. Unfortunately, by May 2026, her cancer had returned, and the treatment options available through the NHS offered little hope for a cure.
Faced with a prognosis of having just six months to live under her current treatment plan, Caitlin has decided to explore potentially curative treatment options abroad, likely in the US. The cost of treatment, along with associated expenses, is estimated at £500,000. Caitlin’s twin sister, Grace Leggett, has left her job as a complex care personal assistant in Bristol to be closer to the family in Cardiff. Grace describes the situation as heartbreakingly difficult as she grapples with the possibility of losing her sister.
“We’re only 24 – nobody expects this to happen,” Grace shared with PA Real Life. “As twins, you’re not supposed to imagine life without the other,” Caitlin echoed. “We’ve navigated life side by side, and I can’t bear the thought of our journey ending here.”
The bond between Caitlin and Grace has always been exceptionally strong, even leading them to share a home during their university days at the University of Bristol. After Caitlin graduated in July 2024, she had ambitions of pursuing a career in the Army with plans to train as an intelligence officer.
Caitlin has been told that she has six months to live (Image: PA Real Life)
She had her mandatory medical assessment scheduled for April 2025, but in March that year she said she developed a rash that persisted despite applying over-the-counter creams from the chemist. Several weeks later, she said she visited her GP, who suspected she might have a virus and requested blood tests to examine further, which were conducted on April 3 2025.
She said she was told to attend the Llewellyn Teenage Cancer Trust unit at University Hospital of Wales in Cardiff the next day, and instantly recognised it was serious. At the appointment on April 4, 2025, she received a diagnosis of acute myeloid leukaemia (AML) – an aggressive cancer affecting the white blood cells.
She was set to undergo her mandatory medical assessment in April 2025, but in March, a stubborn rash appeared, persisting despite using over-the-counter treatments. Concerned, Caitlin visited her GP, who suspected a viral infection and ordered blood tests for further investigation, conducted on April 3, 2025.
According to blood cancer and blood disorder charity DKMS, more than 2,000 people each year in the UK require a blood stem cell transplant, yet just 7% of the entire eligible population in the UK are registered as potential donors. Both Caitlin and her sister Grace had signed up as stem cell donors “years and years ago”, with Grace initially told she would likely be a compatible match for her sister.
Throughout their lives, the pair had believed themselves to be fraternal twins, meaning there was a strong possibility that Grace’s stem cells would be accepted by Caitlin’s body and assist in her recovery. However, genetic testing carried out in June 2025 revealed they were in fact monozygotic twins — meaning they were identical.
Caitlin’s stem cell transplant was delayed due to difficulties finding a donor (Image: PA Real Life)
“I always wished I was an identical twin – I liked being a twin, but being an identical twin is a bit cooler,” Grace said. “It’s really weird to think that I’m basically Caitlin!”
This revelation proved to be a significant setback for Caitlin’s treatment — given their near-identical DNA, Caitlin explained that “the whole concept of the transplant wouldn’t work” as the body must recognise the stem cells as foreign in order for them to target the cancerous cells. Sadly, no other family members proved to be a suitable match either.
While awaiting an alternative donor from the register, Caitlin achieved remission in May 2025 following two months of chemotherapy. However, in August 2025, she learnt that the cancer had returned to her skin – an unusual relapse which, she said, was worsened by challenges in locating a suitable stem cell donor.
Caitlin subsequently participated in a menin inhibitors clinical trial in Manchester to eradicate the leukaemia in her skin, which proved successful and placed her into complete remission – precisely what her consultants required before her stem cell transplant, as it provides a greater chance of success. She was allocated another transplant date in December 2025 with a different donor.
However, a week prior to this second transplant date, the cancer reappeared in her skin. She was still able to undergo the transplant, which occurred in December 2025, but required additional full-body radiotherapy beforehand. The treatment was considered successful and she was informed she was in remission again in January 2026.
Caitlin was subsequently scheduled for monthly bone marrow monitoring for three months, to verify that the cancer had not returned, which were set to reduce to quarterly tests from March 2026, “but I wasn’t too happy about that”, she explained.
“I didn’t feel like it was safe to just go straight to three, so I persuaded my consultant to give me an extra one in May,” she said. “On that extra one, they found that the leukaemia had come back. Initially, the blast count came back at 5.7%, just over remission, but then about a week later it went up to 37%. So it’s quite fast-growing.”
Since May 2026, Caitlin has been participating in a further drug trial for Bleximenib and is awaiting news on whether her body will respond positively. Her medical team have confirmed there is an additional drug trial available should this prove unsuccessful – however, she has been warned that neither treatment offers a cure. She has also been informed that a second stem cell transplant cannot be carried out in the UK, with doctors estimating that her current treatment plan will extend her life by just six months.
As a result, she has resolved to seek curative treatment overseas – with specialised leukaemia care in America or CAR-T cell therapy, a form of immunotherapy, available in China or Singapore, both of which carry a price tag running into hundreds of thousands of pounds. Caitlin and Grace have launched a GoFundMe page entitled Saving Caitlin, aiming to raise £500,000 to fund the costly overseas treatment, along with travel, accommodation and living expenses for accompanying family members, and are “appealing to anyone and everyone to help us in this fight”.
Caitlin said the idea of leaving her identical sister alone is ‘unthinkable’ (Image: PA Real Life)
Without the necessary funds being raised, Caitlin faces the grim reality that she may not reach her 25th birthday. “It’s incredibly difficult to think about,” Caitlin said.
“At 24, I always assumed I had my whole life ahead of me. There are so many things I still want to do, places I want to see, and memories I want to make with the people I love.
“What I would miss most isn’t one particular event, it’s the chance to keep living an ordinary life with the people I love and growing older alongside my twin sister. Those are the things that matter most to me, and that’s why I’m doing everything I can to find another treatment option. I don’t want to miss out on the future we always thought we’d share together.”
Those wishing to support Caitlin can donate to her fundraising page.
