Patients have raised concern after the cost to the NHS of a life-saving drug for people with a rare genetic liver disorder rocketed by around 600% in two years.
Hundreds of people have signed a petition calling for fairer drug pricing regulations and protesting against the steep rise in the price of trientine dihydrochloride in light of the case.
The British Liver Trust said some pharmacies have been reluctant to dispense the drug due to the hikes, and some patients have been referred to their hospital pharmacy to access it.
And the Wilson's Disease Support Group - UK said in its recent AGM summary that the 600% rise in the cost to the NHS of the drug in two years was causing concern to patients and clinicians.
Univar, which has been manufacturing and supplying trientine dihydrochloride for Wilson's Disease patients since 1985, said the size of its business and number of patients taking trientine in the UK is small.
It also said it is investing to provide access to trientine for more Wilson's Disease patients who need it most, has recently made investments in extensive clinical trials and is involved in "compassionate use" programmes through support groups to provide access to the drug at discounted prices.
Jude Pearson, 39, of Brighton, East Sussex, who is behind the online campaign highlighting the issue, said the rises have been imposed by part of an "ugly, greedy" pharmaceutical industry driven by profit.
For 30 years, Mr Pearson has been taking trientine dihydrochloride to successfully control his disorder, Wilson's Disease, which affects around one in 30,000 worldwide.
Diagnosed early enough, Wilson's Disease can be effectively treated. But left untreated and the disease proves almost always fatal.
Mr Pearson said that it used to cost the NHS around £400 for 100 trientine capsules - equivalent to around 16 days' use for him. But he says it now costs the NHS nearly £3,400 for the same amount.
Mr Pearson said the incremental rises have resulted in the NHS being unable to provide him with his prescription for short periods of time. And he sees no justification for the "astronomical" rises as it is a long-established drug that has remained unchanged.
Now Mr Pearson - a St John Ambulance campaign manager - said he and others with Wilson's Disease face concern over how they control the disease amid fears prices will continue to creep up.
He said: "I'm worried really. I have lived totally happily and normally, not really thinking about the disease for 30 years, and now this happens. I worry about what the future holds.
"Can the NHS keep justifying the increased cost when we all know how it is struggling? They are being hit financially from all angles and there will come a breaking point.
"The drug now costs more than I earn. I'm totally dependent on the NHS to provide it for me.
"I understand new drugs cost a lot of money to develop but with long-established drugs such as mine, I find it a bit scandalous that its cost has risen so dramatically."
In its AGM report summary, the Wilson's Disease Support Group - UK said options were limited to challenge Univar, but members were urged to sign Mr Pearson's petition.
There has been a public backlash in the generic drug industry in recent months against "price gouging", when sellers price above the market price when no alternative is available.
The most high profile case involved ex-hedge fund manager Martin Shkreli who was vilified for hiking the price of the only approved drug for a parasitic infection by 5,000% after acquiring its rights.
Shkreli was dubbed "the most hated man in America" and was condemned by figures including Hillary Clinton and Donald Trump, who described him as a "spoiled brat".
Health Secretary Jeremy Hunt in June asked the competition watchdog to look at claims that drug companies were exploiting the NHS to raise the price of generic medicines.
It followed claims that suppliers were able to introduce large price rises by dropping the brand name and taking the medicines outside NHS profit controls.
Andrew Langford, chief executive of the British Liver Trust, said the NHS should not be held "to ransom" by makers of long-established drugs. He was not aware of any patient being denied access to trientine dihydrochloride.
"However, we do know that some pharmacies are reluctant to dispense the drug due to the huge increases in price that we have seen in the last two years and some patients have been referred to their hospital pharmacy to access it," he said.
"Anyone who has had problems accessing the drug should contact the British Liver Trust through their helpline or website.
"The British Liver Trust feels strongly that the makers of long-established drugs that also face very limited competition, such as trientine dihydrochloride, should not be able to hold the NHS to ransom and we would urge the Government to ensure that these drugs are supplied to our health service at affordable levels."
Alastair Kent OBE, director of the charity Genetic Alliance UK, said: "It is difficult to imagine the circumstances that would justify a 600% price hike.
"It seems likely that an increase of this magnitude will make it difficult for patients currently on this medication to receive it and for newly-diagnosed patients to be able to benefit."
Under current arrangements, the Department of Health does not agree the selling price of generic medicines as it is believed competition between suppliers typically keeps prices down.
Officials said there are systems to ensure the NHS gets the best value from buying medicines. The Government has voluntary and statutory schemes in place to consider the prices of branded and generic medicines rather than consider each product individually.
And Government officials believe that while the system works well for most products, they acknowledge there are anomalies, and the system is kept under review.
A Department of Health spokesman said: "No pharmaceutical company should exploit the NHS. They have an obligation to patients to ensure medicines are available and priced fairly.
"Jeremy Hunt has already asked the Competition and Markets Authority to urgently look into allegations of excessive pricing of generic medicines, and will refer future cases as needed."
NHS England said that while the NHS was making big investments in drug treatments this year, it was vital drug firms priced their products responsibly.
An NHS England spokesman said: "The recent public backlash against price gouging in various countries, including the United States, has underlined the need for continuing vigilance on this issue.
"Although the responsibility for reimbursement prices for these medicines lies with the Department of Health, and in general their system delivers value for money for patients, we are concerned about these type of anomalies at a time when the NHS needs to make significant savings which suggests further regulatory action may be needed."
In a statement, Univar said: "While the size of our business and number of patients taking trientine in the UK is very small, for those who may be non-responsive to other therapies, trientine is an important Wilson's Disease treatment alternative.
"We are investing to provide access to trientine for more Wilson's Disease patients who need it most. Recently, we have made investments in extensive clinical trials, which are necessary to meet the evidentiary standards of the European Medicines Agency.
"Working successfully through these clinical and regulatory milestones, in partnership with local health ministries, will enable patients with Wilson's Disease to have increased access to trientine in other EU countries.
"And, if the investment in these broadened evidentiary and clinical studies is successful, we expect a broader acceptance of trientine for health insurance and health plan reimbursement, reducing the financial exposure for patients.
"We also recognise the economic realities of healthcare systems in many parts of the world, and are committed to and actively participate in 'compassionate use' programmes through various Wilson's Disease support organisations that provide access to trientine at discounted prices.
"Within this commitment, we anticipate more than 1,000 bottles of trientine will be allocated in total to compassionate use programs in 2016. Additionally, we have built strong relationships with the Wilson's Disease UK Support Group and continue to contribute to their work in providing patients and caregivers with information and support."