Express Scripts, one of the largest pharmacy benefit managers (PBMs) in the U.S., recently updated its list of preferred medicines to exclude seven common HIV drugs, swapping those drugs for 18 "preferred alternatives."

Following the Express Scripts announcement, a nonprofit advocacy group called The AIDS Institute published a scathing, three-page letter that criticized the formulary change as "bad medicine."

Starting on July 1, Express Scripts' formulary will exclude emtricitabine/rilpivirine/tenofovir disoproxil fumarate (Complera), cobicistat/darunavir (Prezcobix), and cobicistat/elvitegravir/emtricitabine/tenofovir disoproxil fumarate (Stribild). The formulary changes add to prior exclusions that already took effect January 1.

This is "probably one of the most aggressive examples of commercial insurers -- or, in this case, their [PBM] -- attempting to get at drug pricing through formulary design," said Tim Horn, director of medication access and pricing at NASTAD.

Among the issues raised by the AIDS Institute letter, written by deputy executive director Carl Schmid, are that one of the drugs on the preferred alternatives list is no longer available in the United States, and that the formulary changes might lead to disruptions in care.

Published June 3, the AIDS Institute letter ignited a flurry of tit-for-tat accusations between the PBM and The AIDS Institute, with an Express Scripts spokesperson stating that the letter is "full of misinformation," while Schmid accused the PBM of "lying" about its policies.

One of the more stinging accusations in the letter focuses on a drug called delavirdine (Rescriptor) -- one of the "preferred alternatives" for doravirine (Pifeltro). Delavirdine is an NNRTI that was approved in 1997 but is no longer recommended because of issues of cross-resistance, drug interactions, and dosing schedule, according to AIDSMap.

According to the AIDS Institute letter, "One of these 'preferred alternative' drugs was even removed from the market." Schmid confirmed that the letter is referring to delavirdine, and that its status as a "preferred" HIV medication is ultimately useless for patients.

But according to Express Scripts' spokesperson Jennifer Luddy, "That is not true," and the PBM still has "active claims for all the preferred alternatives." A spokesperson for ViiV, the company that sells the drug, confirmed Rescriptor is currently available in the U.S.

The AIDS Institute also accused Express Scripts of implementing policies that will disrupt patient care. The PBM's formulary change announcement specifically instructs patients to speak to their doctors and switch to a preferred alternative "to avoid paying full price."

Meanwhile, The AIDS Institute also argued that creating a rigid list of "preferred" and "excluded" HIV medications may also create disruptions in care -- particularly for patients who may need to switch HIV meds suddenly if they develop resistance or some other problem with a preferred regimen.

On June 5, Steve Miller, M.D., the chief medical officer of Express Scripts, published a response to the AIDS Institute letter, promising that people currently taking an excluded drug would be grandfathered in indefinitely, and that there would be an appeal process for providers who need to prescribe excluded drugs to patients who are new to antiretroviral therapy.

Express Scripts also touted the fact that its preferred formulary list contains drugs that include tenofovir alafenamide (TAF), a safer version of tenofovir disoproxil fumarate (TDF, Viread). Because it is a newer drug, TAF is patent-protected, meaning drugs containing it are likely to be more expensive than TDF-containing regimens.

But the recent formulary change "has less to do with TAF and more to do with Express Scripts playing hardball with all HIV drug product manufacturers," explains Horn. In the future, he adds, "it's possible that we'll see more of this by other PBMs representing other commercial insurers -- safety, efficacy, simplicity, and cost are all now factors on the table."

This messy confrontation between Express Scripts and The AIDS Institute comes at a time when drug prices in the U.S. are at an all-time high. Within HIV, recent new drug approvals mean that patients should have more treatment options than ever before.

Though The AIDS Institute took direct aim at Express Scripts' strategy of using market competition to negotiate steeper rebates with pharmaceutical companies, Express Scripts readily embraced the idea that these negotiations can and should be used to lower drug prices.

"If we are able to get a better rate by excluding another [drug] without compromising patient care -- we think that's a win for the patient," said Luddy, noting that these formula decisions are reviewed by a panel of independent physicians and pharmacists.

Ultimately, said Horn, "what we're likely looking at here is the result of Express Scripts … deciding to cut some older drug products and neglecting to add some of the newer drug products because the manufacturers wouldn't [meet] their rebating demands.

"It's an ugly battle between two health care industry titans, with people living with HIV increasingly caught in the middle," he said.

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