The infliximab-dyyb biosimilar was only moderately less expensive than the originator infliximab product Remicade in the United States in 2017 under Medicare Part D, an analysis shows.
Infliximab-dyyb (Inflectra) cost 18% less than infliximab, with an annual cost exceeding $14,000 in an analysis published online inby , of the division of rheumatology at the University of California, San Francisco, and her coauthors.
However, “without biosimilar gap discounts in 2017, beneficiaries would have paid more than $5,100 for infliximab-dyyb, or nearly $1,700 more in projected out-of-pocket costs than infliximab,” Dr. Yazdany and her coauthors wrote.
Biologics represent only 2% of U.S. prescriptions but made up 38% of drug spending in 2015 and accounted for 70% of growth in drug spending from 2010 to 2015, according to Dr. Yazdany and her colleagues.
Biologics for rheumatoid arthritis (RA) and gastroenterology cost more than $14,000 per year, and in 2015, 3 were among the top 15 drugs in terms of Medicare expenditures, they added.
While biosimilars are supposed to increase competition and lower prices, it’s an open question whether they actually reduce out-of-pocket expenditures for the 43 million individuals with drug benefits under Medicare Part D.
That uncertainty is due in part to the complex cost-sharing design of Part D, which includes an initial deductible, a coverage phase, a coverage gap, and catastrophic coverage.
In 2017, the plan included an initial $400 deductible, followed by the coverage phase, in which the patient paid 25% of drug costs. In the coverage gap, which started at $3,700 in total drug costs, the patient’s share of drug costs increased to 40% for biologics, and 51% for biosimilars. In the catastrophic coverage phase, triggered when out-of-pocket costs exceeded $4,950, the patient was responsible for 5% of drug costs.
“Currently, beneficiaries receive a 50% manufacturer discount during the gap for brand-name drugs and biologics, but not for biosimilars,” Dr. Yazdany and her coauthors noted.
To evaluate cost-sharing for infliximab-dyyb, the authors analyzed data for all Part D plans in the June 2017 Medicare Prescription Drug Plan Formulary, Pharmacy Network, and Pricing Information Files.
Out of 2,547 plans, only 10% covered the biosimilar, while 96% covered infliximab, the authors found.
The mean total cost of infliximab-dyyb was “modestly lower,” they reported. Eight-week prescription costs were $2,185 for infliximab-dyyb versus $2,667 for infliximab, while annual costs were $14,202 for the biosimilar and $17,335 for infliximab.
However, all plans required coinsurance cost-sharing for the biosimilar, they said. The mean coinsurance rate was 26.6% of the total drug cost for the biosimilar and 28.4% for infliximab.
For beneficiaries, projected annual out-of-pocket costs without the gap discount were $5,118 for infliximab-dyyb and $3,432 for infliximab, the researchers said.
Biosimilar gap discounts are set to start in 2019, according to the authors. However, they said those discounts may not substantially reduce out-of-pocket costs for Part D beneficiaries because of the high price of infliximab-dyyb and a coinsurance cost-sharing rate similar to that of infliximab. Because the RA starting dose is typically 3 mg/kg, compared with the 5-mg/kg starting dose for patients with inflammatory bowel disease, cost issues may be worse for GI patients.
“Further policies are needed to address affordability and access to specialty drugs,” Dr. Yazdany and her coauthors concluded.
The study was funded in part by grants from the Agency for Healthcare Research and Quality, the Robert L. Kroc Endowed Chair in Rheumatic and Connective Tissue Diseases, and other sources. Dr. Yazdany reported receiving an independent investigator award from Pfizer. Her coauthors reported no conflicts of interest.