The Food and Drug Administration on Thursday approved Bristol Myers Squibb's Camzyos, the first drug to treat the cause of an inherited form of heart failure known as obstructive hypertrophic cardiomyopathy.
Wall Street analysts, as well as Bristol Myers itself, expect the approval to add billions of dollars of sales to the company's cardiovascular franchise, which is led by the blood thinner Eliquis. The FDA nod also helps validate Bristol Myers' $13 billion buyout of the drug's original developer, MyoKardia.
Obstructive hypertrophic cardiomyopathy is a condition in which the heart muscle thickens and impairs its ability to pump blood. Patients often have symptoms like those seen with heart failure, such as shortness of breath, and until now have been treated similarly, with beta blockers and calcium channel blockers.
Camzyos, previously known as mavacamten, helps heart muscle fibers relax more in between beats, allowing more blood entering the ventricles to be pumped out when they contract and leading to a resolution of symptoms.
With approval in hand, Bristol Myers expects a "bolus" of already diagnosed patients to seek treatment. But the company will face challenges as it seeks to expand Camzyos' use to symptomatic but undiagnosed patients, said Chief Medical Officer Samit Hirawat, in an interview.
Since the symptoms are so similar to diabetes and other cardiovascular conditions, obstructive cardiomyopathy is usually diagnosed when many others have been ruled out, he said in an interview. "Because it’s such a prevalent disease, it should be one of the first thing [doctors] think about when people show up with shortness of breath," Hirawat said.
In order to find patients who need treatment, Hirawat added, cardiologists should look at how such early diagnostic tools as electrocardiograms and echocardiograms might do a better job of identifying the characteristics of the disorder. "If you have a diagnosis it is better to know it, and manage it and follow [treatment] and make sure you’re being assessed," he said.
Camzyos won approval on the basis of a 251-patient study called EXPLORER, in which patients randomized to take the drug had significantly better peak oxygen consumption and improved on a widely used measurement of heart failure when compared to those who got a placebo. Hirawat pointed to a share of patients taking the drug, 27%, whose heart failure symptoms "normalized" when referencing symptoms on the scale.
The drug has a list price of $89,500 for a year of treatment, according to a company spokesperson. That figure is well above the $12,000-$15,000 a year "health-benefit price benchmark" set by the Institute for Clinical and Economic Review, an influential group that evaluates the cost effectiveness of drugs. ICER based its conclusion on the additional benefits of Camzyos over a drug called disopyramide. Moreover, the group said that at a price of $75,000 a year — what Camzyos was assumed to command before approval — two types of surgical interventions delivered a similar health benefit at a lower annual cost.
Bristol Myers said the drug's price "is reflective of its value" as the first and only approved drug for adults with symptomatic, obstructive hypertrophic cardiomyopathy to "improve functional capacity and symptoms," the spokesperson said in an email.
Notably, the approval came with a warning for the risk of heart failure and an FDA-mandated plan to manage that risk. Because Camzyos relaxes heart muscles, patients may experience reduced "ejection fraction," or the amount of blood in the left ventricle of the heart that gets pumped into the arteries.
Patients whose ejection fraction drops below 50% should be taken off the drug, under the risk management plan. The monitoring requirements could become a barrier to use if patients have to make frequent hospital visits, Bernstein analyst Ronny Gal wrote in a January note to clients.
In addition, Gal wrote that a complex dosing protocol and close monitoring as patients begin treatment, designed to keep blood concentrations at a certain range, may mean only heart specialists will be willing to prescribe Camzyos.
The treatment is one of several that Bristol Myers has forecast as reaching $4 billion in sales by 2029, a needed revenue stream as some of the company's top-selling medicines, such as Eliquis and the cancer drugs Revlimid and Opdivo, will lose patent protection later this decade.
Gal forecasts $2.1 billion in 2029 sales, while the consensus of Wall Street analysts is $2.5 billion, he wrote.
While Camzyos will have the market all to itself for now, it could soon be joined by another drug of its type being developed by Cytokinetics. That drug is in a Phase 3 trial in obstructive cardiomyopathy, with data expected sometime in mid- to late-2023.