A mum has said she will be forced to watch her baby daughter die if certain cystic fibrosis medicines are axed.
The National Institute for Health and Care Excellence (NICE) has withdrawn its recommendation for a number cystic fibrosis (CF) medicines due to cost.
Charlotte Perkins, 38, whose 17-month-old daughter Delilah has had CF since birth, said she was "devastated".
NICE said it is evaluating the "cost effectiveness" of the medicines so that "taxpayers continue to get value".
"We are being forced into a situation where we are going to have to watch our daughter deteriorate year on year until she dies at a very young age. I just can't do that," said Charlotte, from Laleston, Bridgend.
Cystic Fibrosis is an inherited condition that leads to problems with breathing and digestion, and affects about one in every 2,500 babies born in the UK.
The lungs of those with the condition become damaged over a number of years and may eventually stop working.
NICE's draft guidance, which is open for consultation until 24 November, said it would not recommend the use of Kaftrio, Symkevi and Orkambi for new cystic fibrosis patients.
However, existing patients will continue to receive the drugs.
Delilah's six-year-old sister has even written to NICE to encourage them to keep her baby sibling's life-saving medicine available.
She wrote that "even though she is still small, she should still get the medicine that bigger kids and grown ups can have".
She added that it was her writing the letter as "Delilah can't write or talk properly yet, so it's my job to be her big sister and stand up for her".
Charlotte said: "It's just unthinkable that they can take these children's lives away from them, when there is a drug that can stop it, give them a full and healthy life.
"Our children deserve their lives, they didn't ask to be born with this condition… she's an innocent baby."
Charlotte said she was told that Delilah would have access to Kaftrio when she turned six, which would "change her life".
"We were told to ignore the life expectancies that we were reading online, we were told that children weren't going to die of this disease anymore," she added.
She said when she first heard the news of the possible withdrawal of the medication she "couldn't do anything for two days".
"I tried to do some things, but we just absolutely fell apart as a family," she said.
Catherine Mayor, 37, whose five-year-old daughter Charli was due to begin receiving the medication for her CF before Christmas, has now been told that may not happen.
"Knowing that this drug is out there, ready for her, but we can't have it potentially because of the cost. It's absolutely, it's just disgusting. It's mind blowing," said Catherine, who lives in Porthcawl, Bridgend county.
"It's absolutely devastating, to be told that everything's going to be okay, your daughter will have a long, healthy life... now to be told, 'oh actually, these drugs are really, really expensive, and we may not be able to afford them'.
"The drugs can add on potentially 30 plus years to the lives of children born now with cystic fibrosis, and they can massively change the quality of life.
"It's absolutely essential for these children to have a chance at life."
Catherine, who is an NHS nurse herself, said she "cannot describe" the feeling of being told the reason the medication for her daughter may be withdrawn is due to cost.
"The only thing I can compare it to is taking your child to the hospital and the treatment is there, it's been developed, it's for her age, but the hospital can't give it to you because of the cost."
Charity Cystic Fibrosis Trust said it is important to remember that the draft guidance from NICE is "not a final decision" and does not affect anyone currently taking the medication.
A spokesperson for the charity said: "We are hopeful that this uncertainty will get resolved in the coming weeks and we have written to the secretary of state and are urging Vertex, NICE, and the NHS to swiftly work together to find a solution.
"We want to urge that the best thing people can do right now is to submit evidence to the NICE consultation before 17:00 on 24 November, and encourage others to do so as well."
'Evaluating the cost-effectiveness'
The Welsh government said it relies "on the advice of independent appraisal bodies including NICE to determine how NHS resources are best utilised".
Helen Knight, director of medicines evaluation at NICE said: "We are evaluating the cost-effectiveness of these cystic fibrosis medicines to ensure that taxpayers continue to get value for money.
"The committee want to hear from stakeholders through consultation on important aspects of its draft conclusions.
"Existing patients and new patients who are started on treatment while the NICE evaluation is ongoing will continue to have access to the treatments."