A raft of new cancer drugs promise better, longer-lasting treatments with fewer adverse side effects -- but their high cost is a growing concern.
Drugs that help the body's own immune cells fight tumors are expected to be used in multi-drug cocktails, pushing the price of therapies costing more than $100,000 a year even higher.
At the same time, other expensive medicines are being combined to produce impressive results fighting diseases including breast and skin cancer.
Price -- just as much as safety and efficacy -- has proved a hot topic for nearly 20,000 oncology experts at the European Society for Medical Oncology (ESMO) annual congress in Madrid.
"It's going to be a real problem for society," said Solange Peters, a cancer specialist at the University Hospital of Lausanne and a member of ESMO's educational program. "We are working to make oncologists more aware of the costs."
It all spells an increased financial burden for healthcare systems already struggling to meet the demands of aging populations, and for individuals who have to pay out-of-pocket costs in markets such as the United States.
"Financial toxicity, or more generally the financial burden of disease, is a side effect just as potent as fatigue or nausea in patients," consultancy IMS Health said in a report last week, noting the average price of cancer drugs had almost doubled in the past decade to $10,000 a month.
America's Health Insurance Plans, representing U.S. insurers, says it is alarmed by a coming flood of new cancer treatments that will carry "astronomical price tags", while pricing rows have also flared in Britain, France and Italy.
By blocking a tumor's ability to camouflage itself from attack by the immune system's cells, immunotherapy has the potential to send cancer into long-term remission.
The approach has come of age this month with the first U.S. approval of a drug blocking a protein known as Programmed Death receptor, or PD-1, from Merck and the first late-stage trial results for another PD-1 drug from Bristol-Myers Squibb presented at ESMO.
High prices are central to forecasts that sales of these new immune-boosting drugs from companies like Bristol-Myers Squibb, Merck & Co, Roche and AstraZeneca may top $30 billion a year.
But an ESMO survey showed patients in poorer parts of Europe already lack access to existing drugs such as Roche's Herceptin for breast cancer, so immunotherapies are likely to be out of reach in most of the 131 countries represented in Madrid.
Immunotherapies seem to work in more and more cancers, suggesting they could become the backbone of treatment in much the same way that chemotherapy is today.
Clinical updates in Madrid showed the efficacy of such therapies extending well beyond melanoma -- the initial focus -- to lung, kidney, bladder, head and neck, and stomach cancer.
ESMO president Rolf Stahel said they were likely to prove especially useful in diseases such as kidney and lung cancer, where slow growth favors the immunological approach.
Still, the new immunotherapies only help some patients and they do not act as quickly as other targeted drugs, suggesting the best approach will be to develop cocktails of medicines.
"Our vision is combinations," said Johann de Bono from Britain's Royal Marsden Hospital and head of ESMO's scientific committee. "We have new avenues for really changing practice globally, though there are obviously fiscal costs and concerns."
So far, doctors only have access to two types of immune system checkpoint inhibitors -- PD-1, plus the related target PD-L1, and CTLA4. But there are many other brakes and accelerators on the immune system that may be targeted. Some, like OX40, are already the subject of early trials.
Jeffrey Weber, a cancer doctor at the Moffitt Cancer Center in Florida, who has led much of the research on Bristol-Myers' immune system drug Opdivo, is a big believer in the potential of immunotherapy but shares the concerns about costs.
"We've kind of maxed out what we're either willing or able to pay for these kinds of drugs, so it's a problem when you start combining them," he said.
"It can't just keep going exponentially, so that eventually it will be $1 million a year to get treated -- that's crazy."
Competition between companies may help drive down the cost, he believes, since there is no strong evidence as yet to differentiate the new PD-1 or PD-L1 drugs, which he expects to play a central in future drug combinations.
There is also debate as to whether cancer patients should be tested before treatment to see if their tumors carry biological markers that would make them more likely to respond, thereby limiting the numbers eligible for therapy.
Such biomarkers are already used for other cancer drugs that only work if there is a specific gene mutation. But the situation is not black and white with the new treatments and some oncologists worry it could exclude patients who might benefit.
Drugmakers argue they need a fair price as reward for their investment, with cancer accounting for 23 percent of the $70 billion spent by the industry on research last year, according to Thomson Reuters unit CMR International.
But they acknowledge the public purse is not bottomless.
"The willingness to pay in oncology will remain higher than in other therapeutic areas, because of the high need, but there will be a ceiling," said Joerg Barth, head of oncology at Germany's Boehringer Ingelheim.