There is a drug for one particular kind of incurable breast cancer that, in the trial that made its name, gave women roughly six extra months of life compared with standard chemotherapy. Six months does not sound like a headline. If you are the one counting, it is a school year, a wedding, a grandchild, an entire summer you were told you would not get.
Patients in Scotland have been able to receive that drug on the health service since the end of 2023. Patients in England could not. Same country, same health service in name, same disease, different answer. The medicine was approved there and refused here, and the refusal was not about whether it worked. Nobody ever argued it did not work. The argument was about the price.
That standoff ended recently. The National Institute for Health and Care Excellence, the body that decides which medicines the health service in England will pay for, reversed a rejection it had published two years earlier, and the drug went into use. The people who spent those two years campaigning did not celebrate cleanly. They said out loud what everyone involved already knew, which is that thousands of people were eligible during the gap and a number of them are not here to hear the news.
The drug is trastuzumab deruxtecan, sold as Enhertu, made by Daiichi Sankyo and marketed with AstraZeneca. It is worth being precise about who it is for, because health stories get blurred into false hope faster than almost any other kind, and this one has already been blurred enough.
It is not for everyone with breast cancer. It is not a cure. It is approved for adults with HER2-low breast cancer that is metastatic or cannot be removed by surgery, meaning the disease has spread beyond the breast or sits somewhere an operation cannot reach, and it is for people who have already had chemotherapy for that advanced disease. HER2 is a protein that sits on the surface of some cancer cells. For years the test was treated as a yes or a no. You were HER2 positive, which opened the door to targeted drugs, or you were HER2 negative, which did not. HER2-low describes the large group in the middle, people whose tumours carry some of the protein but not enough to have counted under the old line. For that group there had never been a licensed targeted treatment. There was chemotherapy, and then there was more chemotherapy.
How the drug works is easier to picture than the name suggests. An antibody finds the HER2 protein on a cancer cell and attaches to it, and bolted to that antibody is a chemotherapy payload that gets delivered at the cell rather than sprayed across the whole body. Patients receive it as a drip, roughly once every three weeks, for as long as it keeps working and they can tolerate it. Like any cancer treatment it has side effects, some of them serious, and whether it is suitable for any individual is a conversation for that person and their oncologist rather than anything that can be settled by an article.
The evidence came from a trial called DESTINY-Breast04. Reported figures vary slightly depending on which analysis and which write-up you read, which is normal as trial data matures. Broadly, women receiving the drug lived for something in the region of 23 to 24 months, against roughly 17 months for those on the chemotherapy they would otherwise have been given. The time before the disease started growing again was close to ten months, against about five. Call the survival benefit somewhere around six months on average. Some people get less than that. Some get a great deal more, and it is the people who get a great deal more who make the averages feel so inadequate to the individuals living inside them.
So why did England say no in the first place, when Scotland, which runs its own appraisal system through the Scottish Medicines Consortium, had already said yes at the end of 2023?
Because the two systems asked slightly different questions and arrived at different answers, and because of a piece of arithmetic almost nobody outside the field had heard of until this drug ran into it.
Health systems that pay for medicines out of a fixed public budget have to have some way of deciding what a treatment is worth, since every pound spent on one drug is a pound not spent on another. In England the unit used is the quality-adjusted life year, one extra year of life in good health. The appraisal body works out roughly how much a new medicine costs per quality-adjusted life year it delivers, and compares that against a threshold. For a long time that threshold sat at around 20,000 to 30,000 pounds, which is very roughly 27,000 to 40,000 US dollars. Above the top of the range, a medicine is generally judged too expensive for what it gives.
There have always been exceptions for the most desperate cases. Until a few years ago there was a specific end-of-life allowance that let terminal treatments be valued more generously. That was replaced with something called a severity modifier, which weights the threshold according to how severe the condition is, and which was designed to spread the flexibility more evenly across diseases rather than concentrating it at the very end of life.
Enhertu was one of the first end-of-life breast cancer treatments assessed under the new arrangement, and the arithmetic went against it. It did not qualify for the highest severity weighting. Without that weighting, at the price the manufacturers were offering, the appraisal committee judged that the cost was too high relative to the benefit.
The process dragged. A provisional rejection came in late 2023. Talks were paused so the companies and the health service could negotiate. By spring 2024 no agreement had been reached, and after pressure from a parliamentary committee the two sides were given more time. That extra time did not produce a deal either, and the final guidance was published in the summer of 2024. The body’s director of medicines evaluation, Helen Knight, said plainly that the companies had not put forward a new price, so there was no choice but to publish the decision, and that the fastest and only guaranteed route to patients was for manufacturers to offer a fair one. AstraZeneca’s UK president blamed the outcome on rigid application of a flawed methodology. Both of those positions are exactly what you would expect each side to say, and both of them contain something true.
It is worth sitting with what that decision meant at the time, because it was not an ordinary one. This was the first breast cancer medicine the English appraisal body had turned down in years, after a long unbroken run of approvals. Breast Cancer Now, the charity that led the campaign, called it a dark day and later described it as an avoidable tragedy. Around a thousand people a year in England were estimated to be eligible. Meanwhile the drug was funded in Scotland, and across more than two dozen European countries, and in Canada, which meant a woman with exactly the same diagnosis could be receiving it or not receiving it depending on which side of an internal border her postcode fell on.
That is the part that made people furious, and it is the part that kept the campaign alive for two years when most campaigns of this kind quietly fade.
Paula Van Santen was diagnosed with metastatic breast cancer four years ago. She has three children. When the approval finally came she said there were not enough words for how she felt, and the things she listed as what she wanted more time for were ordinary in the way that only becomes extraordinary when you might miss them, seeing a daughter graduate, becoming a grandmother, staying present in her children’s lives rather than being a person they remember.
Kathryn Hulland was diagnosed the same year. Her daughter Grace is nine. At the point of diagnosis she was told she would be lucky to see twelve months, and she is now three years past that conversation, which is why she talks about extra months the way other people talk about money. She knows the exact denomination.
Another campaigner, a 62-year-old woman from the south coast of England, put the cost of the delay in the only unit that really counts. Since the campaign began, four of the people she had been campaigning alongside had died. Those were not strangers to her. They were the people she sat with in meetings about a drug none of them could get.
What finally broke the deadlock was not a change of heart about the medicine. It was a change to the arithmetic, plus a price.
Earlier this year the thresholds the appraisal body works to were lifted, from roughly 20,000 to 30,000 pounds per quality-adjusted life year up to roughly 25,000 to 35,000, which is about 34,000 to 47,000 US dollars. That change came out of a pharmaceutical pricing agreement between the UK and the United States, in which American pressure over drug pricing played a significant part. The way quality of life is assessed within appraisals was also revised. On top of that, the manufacturers and the health service reached a commercial agreement. The terms of that agreement are confidential, as these deals routinely are, so nobody outside the negotiation knows what the health service is actually paying, and it would be irresponsible to guess.
With the threshold higher and a new price on the table, the same drug that had failed the test in 2024 passed it, and the guidance was reversed. The medicine became available through the health service in England, for that same group of around a thousand people a year.
There is a genuine argument on the other side of this, and it deserves to be stated rather than waved away, because the people making it are not villains either.
Raising the threshold does not create money. It moves it. Every medicine now approved under the more generous arithmetic is funded from the same finite budget that pays for nurses, scanners, hip replacements and mental health services. Members of parliament have estimated that the wider pricing arrangement could cost the health service in the region of a billion pounds over three years, something close to 1.3 billion US dollars, and the chairs of six parliamentary committees asked the national audit body to examine it. Their concern is not that women with secondary breast cancer should go without. It is that a threshold raised under trade pressure from another country is a strange way to decide domestic health spending, and that the money has to come from somewhere, and that whoever it comes from will never be identifiable the way Paula and Kathryn are identifiable.
Both things are true at once. A person who gets six more months with their nine-year-old is visible and named and photographable. The person who quietly waits longer for something else because the budget went elsewhere is a statistic nobody will ever interview. Systems like this exist precisely because somebody has to make that trade deliberately rather than by accident, and the people who do it are not enjoying it.
The charity’s chief executive, Claire Rowney, called the approval a momentous day for thousands of people, and in the same breath acknowledged those who had died since the rejection. Helen Knight, the official who had announced the original refusal, said openly that the decision had come too late for many families. That is a rare thing to hear from an institution, and it was the correct thing to say.
Where it stands now is not tidy. The drug is available on the health service in England and in Scotland. Wales and Northern Ireland were still working through their own arrangements when the English decision landed, which means the geography problem has not disappeared so much as shifted. The campaigners who spent two years on this immediately turned to that.
And the women at the centre of it are doing the thing that is easy to write and impossible to live, which is getting on with it. Kathryn is three years past a twelve-month prognosis, raising a nine-year-old who is old enough now to understand some of it. Paula is counting toward a graduation. Neither of them has been cured, and neither of them has claimed to be. What they have is a treatment that was always going to work as well as it works, held up for two years by a disagreement over what it should cost, and then released by a change to a formula.
The uncomfortable thing about the ending is that nothing about the science changed in those two years. The drug did the same thing in 2024 that it does now. What changed was the number it was measured against, and the number the companies were willing to accept. That is how medicines actually reach people, and it is worth knowing, because the next time a treatment is turned down the question to ask is not whether it works. It is what it costs, who decided, and what they measured it against.