Although recent trial results have established the sodium glucose cotransporter 2 inhibitors dapagliflozin and empagliflozin as a key new part of the recommended multidrug treatment regimen for patients with heart failure with reduced ejection fraction, the current U.S. cost for dapagliflozin means it has merely “intermediate” value when it comes to cost-effectiveness.
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A typical regimen with dapagliflozin to treat patients with heart failure with reduced ejection fraction (HFrEF) costs about $474/month or roughly $5,700/year based on Medicare pricing. After factoring in the incremental clinical benefits producing by dapagliflozin seen in the DAPA-HF pivotal trial that helped establish its role, this price produces a cost per quality-adjusted life-year (QALY) gain of about $84,000, which puts dapagliflozin squarely in the intermediate range for value set in 2014 by a task force of the American College of Cardiology and the American Heart Association.
This cost-effectiveness value depends largely on the proven efficacy of dapagliflozin (Farxiga) for decreasing the incidence of cardiovascular death among treated patients with HFrEF, and puts the drug’s value roughly on par with another agent recently approved to treat such patients, sacubitril/valsartan (Entresto), which carries a cost-effectiveness value of about $45,000/QALY.
The U.S. cost per QALY for dapagliflozin treatment of patients with HFrEF dwarfed the value numbers calculated for several other countries that were generally one-tenth this size. This disparity stemmed from both the relatively high price for dapagliflozin in the U.S. compared with other countries – nearly tenfold higher – and relatively higher costs for all types of U.S. medical care, Justin T. Parizo, MD, and coauthors said in a recent report. But the cost, and hence the cost per QALY, of dapagliflozin may soon drop because certain patents on the drug expired in October 2020, added Dr. Parizo, a cardiologist at Stanford (Calif.) University, and associates. Despite the expired patents, as of June 2021 no generic form of dapagliflozin appeared available for U.S. sale.
Medicare patients pay about $1,630/year out-of-pocket
“A key caveat” to this finding for dapagliflozin is that being cost-effective “is not by itself a mandate for routine clinical use,” Derek S. Chew, MD, and Daniel B. Mark, MD, said in an editorial that accompanied the report.
A major stumbling block for widespread U.S. prescribing of dapagliflozin to patients with HFrEF is its overall price tag for U.S. patients, estimated at $12 billion/year, as well as an out-of-pocket annual cost for individual Medicare patients of roughly $1,630/year. Adding this out-of-pocket cost to the copay for sacubitril/valsartan and two other much less expensive drug classes that together form the current mainstay, quadruple-drug regimen for HFrEF treatment means a potential annual cost paid by each Medicare patient of about $3,000, wrote Dr. Chew, a cardiologist, and Dr. Mark, a cardiologist and professor, both at Duke University, Durham, N.C.
They cited the precedent of the “unexpectedly slow” and “anemic” uptake of sacubitril/valsartan since its U.S. approval in 2015, a cost-effective agent with “comparable clinical effectiveness” to dapagliflozin. “Even with full inclusion [of sacubitril/valsartan] on formularies and elimination of preapproval requirements, use remains very low, and patient-borne out-of-pocket costs may be a key factor,” wrote Dr. Chew and Dr. Mark. They cited a results from a study that showed abandonment of new prescriptions at retail U.S. pharmacies spiked to a 60% rate when out-of-pocket cost exceeded $500.