Tens of thousands of Americans will soon be forced by their heath insurance to switch from one popular obesity drug to another that produces less weight loss.
It is the latest example of the consequences of secret deals between drugmakers and middlemen, known as pharmacy benefit managers, that are hired by employers to oversee prescription coverage for Americans. Employers pay lower drug prices but their workers are blocked from getting competing treatments, a type of insurance denial that has grown much more common in the past decade.
One of the largest benefit managers, CVS Health’s Caremark, made the decision to exclude Zepbound in spite of research that found that it resulted in more weight loss than Wegovy, which will continue to be covered.
Those research findings, first announced in December, were confirmed in an article published on Sunday in The New England Journal of Medicine. The study involved a large clinical trial comparing the drugs that was funded by Eli Lilly, the maker of Zepbound. Earlier research not financed by Eli Lilly reached similar conclusions.
Ellen Davis, 63, of Huntington, Mass., is one of the patients affected by Caremark’s decision. “It feels like the rug is getting pulled out from under my feet,” she said.
After taking Zepbound for a year, she has lost 85 pounds and her health has improved, she said. She retired after working for 34 years at Verizon, which hired Caremark for her drug coverage.
In a letter to Verizon, she complained, “This is forcing patients to switch medications against their will, and without medical justification, to a less effective medication.”
Verizon did not respond to requests for comment.
Word spread quickly online about the change after Caremark announced it this month. A physician assistant at a weight-loss clinic in New Hampshire set up a change.org petition urging the company to reverse course. It had more than 2,700 signatures as of Sunday afternoon. Caremark intends to stop coverage for Zepbound in July.
Doctors say that Wegovy, made by Novo Nordisk, and Zepbound are both good drugs, but that they prefer Zepbound for most patients. Now they will have far less ability to tailor obesity drug prescriptions to individuals.
It is not clear whether excluding Zepbound will lead to higher profits for Caremark.
Executives at Novo Nordisk said they did not seek to block Zepbound. They have distanced themselves from Caremark’s move, saying that patients and doctors should be able to choose which drug to use.
David Whitrap, a spokesman for Caremark, said the company made the decision in an effort to lower drug prices. He said the deal would reduce the price that Caremark’s employer clients paid for obesity drugs by 10 to 15 percent compared with the previous year.
“CVS Caremark was able to do what P.B.M.s do best: compete clinically similar products against one another, and choose the option that delivers the lowest net cost for our clients,” Mr. Whitrap said.
Asked about the research showing an advantage for Zepbound, Mr. Whitrap said that both drugs are highly effective and that clinical trial results often differ from the results seen in the real world.
The exact prices employers pay for the drugs are secret. A typical monthly price for large employers is between $550 and $650, according to the Health Transformation Alliance, a group of large employers.
Without using insurance, patients can get the drugs for $500 a month in most cases. They recently lost a cheaper option when regulators halted sales of copycat versions that sometimes cost under $200 a month.
Many employers won’t pay for either Zepbound or Wegovy because they’re so expensive. Medicare does not cover the drugs for most patients with obesity, and the Trump administration recently rejected a Biden plan for expanded coverage.
Caremark and two other benefit managers together control 80 percent of the prescription market. The others, Cigna’s Express Scripts and UnitedHealth’s Optum Rx, have not taken similar actions to block either of the weight-loss drugs.
Starting in 2012, the large benefit managers have increasingly used these moves for a range of medications, upsetting patients and disrupting treatments. Drugs are suddenly dropped from the benefit managers’ periodically updated lists of covered medicines, known as a formulary.
In an analysis funded by drugmakers, researchers found that the number of medications excluded from at least one P.B.M. list increased to 548 in 2022 from 50 in 2014. The researchers counted only cases in which patients were forced to use a wholly different drug, not just moved to a generic version or other replica.
The restrictions frequently change, and patients aren’t told why. One P.B.M. will cover one drug but not another, while a competing benefit manager will do the opposite.
Most of the time exclusions don’t harm patients, according to experts. In some cases, they can even be beneficial, if patients are forced to switch to a drug that ends up working better for them.
But some exclusions spark uproars among patients and doctors.
In 2022, Caremark forced patients to switch from one widely used blood thinner, Eliquis, to Xarelto. There were a few anecdotal reports of blood clots in patients whose treatment was interrupted by the change. Doctors groups sharply criticized Caremark’s move. The company reinstated coverage of Eliquis six months later.
People with autoimmune conditions like arthritis are also frequently forced to change drugs. People with asthma must move to a different inhaler, and then switch to another one.
“It has just become increasingly intrusive,” said Dr. Robyn Cohen, an asthma specialist at Boston Medical Center.
Patients who have Caremark are already inundating employers with calls and emails, asking whether they will be affected, according to representatives of employers. They sign off on the benefit managers’ lists of medicines, but do not play an active role in creating them.
Caremark’s change applies only to some people with private insurance whose employer opted for the benefit manager’s most popular list of medicines. The move will not affect patients who take versions of the drugs for diabetes.
Patients will have the option of switching to Wegovy or one of three other weight-loss drugs that are not popular because they are not very effective.
Mr. Whitrap said Caremark would offer a “case-by-case medical exception process for individuals who may need an alternative,” such as patients who previously took Wegovy and did not lose much weight.
But many people will not qualify for an exemption. In interviews, patients said that they had specifically sought out Zepbound and didn’t want to switch.
“I chose Zepbound with my doctor,” said Carl Houde, 49, of Saugus, Mass. “For that to then be taken away, it’s distressing.”
Some patients said they were considering using their own money to stay on Zepbound. For Victoria Bello, 28, of Syracuse, N.Y., Zepbound has brought substantial health benefits and she is concerned about losing it.
“I didn’t expect it to change out of nowhere,” she said. “I’m worried about the future of my health and that my health progress will stall.”
The Eli Lilly-funded study directly compared the drugs in a clinical trial of 750 people over more than 16 months.
People on a high dose of Zepbound lost 50 pounds on average, compared with 33 pounds for people taking Wegovy. Both drugs, which patients take as injections, cause side effects like nausea, vomiting, diarrhea and constipation. In the study, the rates of those side effects were generally similar between the two drugs. In both groups, a small number of patients stopped taking the medicines because of side effects.
The two drugs work in a similar way but have an important difference. Wegovy mimics the effects of just one hormone involved in appetite. Zepbound does so with two. Scientists believe that imitating more hormones will lead to more weight loss.
Dr. Jason Brett, an executive at Novo Nordisk, said in an interview on Friday that the number of pounds patients lose is only one part of treating obesity. Both drugs have shown they can improve heart health, but only Novo Nordisk has won regulatory approval to market its drug that way.
Doctors argue that both drugs should remain available because some patients in fact do better on Wegovy than on Zepbound, losing more weight or experiencing fewer or milder side effects.
Doctors say that because of the variation in how patients respond to either Wegovy or Zepbound, having both available is optimal.
Caremark’s defenders say it was just doing its job in deciding to block Zepbound.
Benefit managers negotiate with drug manufacturers to get payments, known as rebates, that ultimately reduce prescription drug costs for employers. As part of these deals, manufacturers also pay fees to P.B.M.s. Those fees can add up to hundreds of million of dollars for the biggest blockbusters. Caremark stood to receive substantial fees for the weight-loss drugs even without excluding Zepbound.
Novo Nordisk and Eli Lilly have a duopoly in the booming market for weight-loss drugs, but Novo Nordisk has been losing market share to Eli Lilly.
Caremark negotiated with both drugmakers about how much they would pay in rebates to keep their product available. Neither Novo Nordisk nor Eli Lilly would say how much it offered. Novo Nordisk said it did not ask or pay to block Zepbound, contending that the exclusion was entirely Caremark’s decision.
“We believe it’s in the best interest of patients and physicians that they can make the choice,” Novo Nordisk’s chief executive, Lars Fruergaard Jorgensen, told Wall Street analysts this month.
Elisabeth Degallier, 56, of Rochester, Minn., said Zepbound had been life-changing. She is angered by Caremark’s decision. “I felt that they weren’t looking at the science,” she said. “They were looking at the dollars.”
She added, “It makes me scared for the future. I’m on a couple other expensive medications that I really depend on. Are they just going to cut those too?”