The potential savings from prescribing generic antiretrovirals predicted by economic models may be overstated and numerous barriers need to be overcome to bring down the cost of HIV treatment in higher-income countries, according to the findings of several recently published analyses.
Switching to cheaper generic versions of some antiretrovirals has been proposed as a means of freeing up money to treat more people with HIV in the United States and other higher-income countries where generics are beginning to become available. One modelling study estimated that nearly $1 billion would be saved in a single year if everyone taking Atripla (efavirenz/tenofovir/emtricitabine) switched to generic efavirenz and lamivudine plus branded tenofovir (Viread).
But in an article for the New England Journal of Medicine, Erika Martin of the State University of New York and Bruce Schackman of Weill Cornell Medical College identify a number of barriers that stand in the way of the more optimistic scenarios.
Scepticism among healthcare providers, patients and pharmacists about the safety and efficacy of generic medications is an important barrier, the authors say. A systematic review of studies of perceptions of generic medications in the general population found that around one in three lay people viewed generic medicines as less effective. Similarly, one in three lay people had a negative attitude towards generic substitution. Pharmacists were significantly more likely to view generics as inferior quality products compared to doctors or lay people, even though generic drugs must pass stringent quality tests to be approved for use in the United States and European Union.
In the United States, the financial incentives to switch to generic drugs are not consistent, unlike in single-payer systems. England’s National Health Service can phase out the use of branded products by tendering for drug supplies and by setting targets for switching patients from branded products to generics. For example, NHS England decided in 2016 to switch at least 95% of patients from branded abacavir/lamivudine to a generic equivalent to save £15 million over two years.
In the United States, on the other hand, the potential incentives for using generic drugs will depend on who is paying for antiretroviral drugs. Whereas generic substitution is likely to save money for privately insured patients and insurers, it may not do so for treatment covered by AIDS Drug Assistance Programs (ADAP), by Medicaid or in clinics eligible for the federal government 340B drug pricing programme. This is because these payers qualify for discounted federal prices on some branded products.
To show how this works, the authors compare the potential costs of several recommended first-line regimens. Whereas the average monthly wholesale acquisition cost of Triumeq, the branded single-tablet regimen containing dolutegravir/abacavir/lamivudine is $2599, the average monthly cost of branded dolutegravir (Tivicay) plus generic abacavir/lamivudine is $1932. Government programmes would achieve a similar saving by using generics with Tivicay.
In contrast, use of generic lamivudine instead of emtricitabine would be no cheaper for government programmes if prescribing raltegravir (Isentress) and tenofovir/emtricitabine (Truvada) or tenofovir alafenamide/emtricitabine (Descovy), owing to the discount on branded drugs given to these programmes. This may be an example of generic competition pushing down the price of branded products, but new and superior entrants to the market and a succession of co-formulations have postponed the day when the standard first-line regimen in higher-income countries will consist entirely of generic drugs and cost less than $90 a year.
Willingness to switch to generics among patients will also be affected by the structure of health insurance co-payments: if patients must co-pay for each drug prescribed, switching from a branded single-tablet regimen to a multi-pill will increase their out-of-pocket costs.
