In the Specialty Drug Spend, Biologics Rule

Biologics are among the highest priced drugs, so even if they account for a relatively small proportion of the prescriptions, they have an outsize effect on drug expenditures.

The report on specialty drugs issued by the Pharmaceutical Strategies Group (PSG) last week adds just a bit more evidence to support this fundamental math about U.S. drug expenditures.

Although there is some shuffling among the rankings among them, 9 of the top 10 drugs by expenditure in 2023 were biologics, according to the report, which is based on datafrom PSG clients that allow their data to be used for research and benchmarking purposes. The lone exception is Trikafta, a drug used to treat cystic fibrosis that consists of three related small molecules: elexacaftor, tezacaftor, ivacaftor.

The other nine drugs on the PSG’s top 10 list in rank order of expenditure, a function of utilization and price, is Humira (adalimumab),Stelara (ustekinumab), Skyrizi (risankizumab), Dupixent (dupilumab),Keytruda (pembrolizumab), Enbrel (etanercept), Tremfya (guselkumab), Taltz (ixekizumab) and Ocrevus (ocrelizumab). Trikafta is in number 8 position, between Tremfya and Taltz.

Humira’s position at the top of this list is not a surprise, although biosimilars are making a dent in Humira sales this year. The PSG report notes that Skyrizi moved up from number 6 on this list in 2022 to number 3 in 2023. Humira and Skyrizi are both made and marketed by AbbVie. Tremfya also moved up, from 10th in 2022 to seventh while Keytruda slid from third to fifth and Enbrel from fifth to sixth.

Seven of these top 10 drugs, all of them biologics, are used to treat inflammatory disorders, such as Crohn’s disease, atopic dermatitis and psoriasis: Humira, Stelara, Skyrizi, Dupixent, Enbrel, Tremfya and Taltz. The exceptions among the biologics are Keytruda, a cancer drug, and Ocrevus, a multiple sclerosis drug.

Although the overall math of the specialty drug spend is the same, the PSG report points to some shifts. The percentage of people being prescribed at least one specialty drug is creeping up. According to the report, 5.3% of the members of the PSG clients included in the report were using at least one specialty drug in 2021. In 2023, that proportion had grown to 5.9%.

The other specialty drug shift described by PSG from the medical benefit to the pharmacy benefit. In 2021, 60.2% of specialty drug spend was through the pharmacy benefit. In 2023, that proportion edged up to 63.8%. PSG said the change is the result of fewer special handling requirements for specialty drugs and more self-administered formulations.

The report also notes that plan sponsors are using strategies to move drugs to the pharmacy benefit to maximize rebates and “optimize utilization management, which can be done more robust [sic] within pharmacy.”