Formulary attributes: An influencer of drug access

A review of  2019 prescription drug sales in the United States reveals Humira, Enbrel, Revlimid, Imbruvica and Keytruda to be on top of the chart (DRG Sales data).

Their specialty status and utilization volume make these drugs ideal candidates to ascertain relation between formulary management in commercial plans and drug access.  Highlights of the analysis are:

  • Utilization management through prior authorization and step therapy will determine access to drugs more so than coverage status.
  • Humira’s preferred status on formularies coupled with its unrestricted status in an additional 7 percent of formularies promote the drug’s access over Enbrel.
  • Although Keytruda’s pharmacy coverage has shrunk by 25 percent from January 2019, the drug continues to enjoy less restrictive coverage over Opdivo. 


TNF inhibitors: HUMIRA, ENBREL

In the United States, Humira has earned the highest revenue for 2019 and has been a consistent performer, but the drug approaches its peak with impending biosimilar entry. Enbrel has long been Humira’s competitor and ranks 5th as per U.S. drug sales for 2019.
As of December 2020, Humira has favorable formulary placement over Enbrel in more than 700 commercial plan formularies. Humira also has lower instances of prior authorization requirements and has fewer utilization management tools applied to the drug. Humira’s superior formulary status combined with its less restrictive position enables the drug to outperform Enbrel in sales.

Both TNF inhibitors are covered primarily under pharmacy benefits with hardly any difference when covered through the medical benefit (DRG Formulary Analytics). Enbrel and Humira have been successful at wa rding off biosimilar entry short-term. However, biosimilars of other biologics and new classes like JAK inhibitors threaten Enbrel’s market position.



Revlimid is typically covered under pharmacy benefit and remains at a preferred tier or a specialty tier in about 90 percent of commercial formularies. Revlimid, which treats multiple myeloma, mantle cell lymphoma and myelodysplastic syndromes, continues to be an elite seller after multiple price increases. After pushing the launch of its generic to 2026, Revlimid has received additional use cases. With indication expansion and a possible biosimilar out of the way, Revlimid’s formulary presence may be secure, so should its revenue.

Imbruvica, which is on most formularies, has obtained eleven FDA approvals in the past six years.  A long-standing therapy for Chronic Lymphocytic Leukemia, Imbruvica still manages to hold on to major revenue share. But competition from Calquence and other prospective competitors could challenge its position. Currently, Imbruvica continues to have preferred tier and reduced restrictions as compared to Calquence, which lags in formulary coverage by a little over 5 percent (DRG Account Management Dashboard). Also, Calquence has not been successful in improving its formulary positioning since January 2019 and has lost preferred status in some commercial formularies.

Keytruda is an antineoplastic being used for several conditions. The drug, which has very few competitors, is almost always covered through medical benefit and when covered through pharmacy benefits and is preferred for over 18 percent commercial lives. Opdivo, one of Keytruda’s competitors has secured better formulary placement over Keytruda. However, when covered through pharmacy benefits, Keytruda has less restrictions, like prior authorization, imposed (DRG Account Management Dashboard). Expect Tecentriq and Imfinzi to emerge as direct competitors for Keytruda as these drugs come up in the anti-PD-(L)1 market.


Formulary management determines drug access on paper and acts as a precursor to utilization driven sales of drug. For all five drugs considered, formulary placement and utilization management are foundational to their market presence in the U.S. Thus, as specialty and emerging therapy spend experiences an upward trend, focus on utilization monitoring and formulary design will intensify.