why are there so few generic hiv drugs

When Advancing Sciences Hamper Generic Drug Development

Typically speaking, when a patent of a drug expires (usually 20 years after the patent was first filed), the right to copy that drug will be open to anyone who chooses to create a generic version.

The goal of the generic is to compete with the original product on price, with more players spurring greater competition and, more often than not, lower costs.

So why haven’t we seen this with HIV drugs? After all, the patents for a long list of antiretrovirals have either expired or are soon to expire, including such former “superstar” drugs as Sustiva (efavirenz) and tenofovir (TDF).

But when you check the registry of the Food and Drug Administration (FDA), generic formulations have only been submitted and approved for six drug agents. Of these, a third are infrequently used in the treatment of HIV in the U.S. (stavudine and didanosine), while all but two (abacavir and lamivudine) are falling out of favor.

And therein lies one of the challenges facing generic manufacturers in the HIV space: Fast-changing science can make certain drug agents obsolete.

Waning Demand Diminishes Generic Competition

Take, for example, Rescriptor (delavirdine) and Aptivus (tipranavir), two fine HIV medications whose patents expired in 2013 and 2015, respectively. While both are still used in the treatment of HIV, other, newer-generation drugs (particularly integrase inhibitors) have been granted preferred status. These drugs, meanwhile, have been downgraded to alternate status.

As a result, Rescriptor and Aptivus will more often be used as a “fall-back” when other treatments fail. This alone decreases the incentive for manufacturers to jump into generic production when there is less assurance of volume sales.

Similarly, while a drug like TDF is still among the most widely used in the world, an improved version—called tenofovir alafenamide (TAF)—was introduced in 2016 just as TDF’s patent was set to expire.

A conspiracy perhaps? Not really, given that the newer form offers far fewer side effects and higher, steady-state blood concentration levels (meaning that the drug stays in your system longer). In the end, TAF is a superlative drug that will rightly supplant TDF, particularly in newer combination tablets.

So, does that mean we won’t be seeing generic forms of TDF anytime soon? Most believe that we will. Even in the face of waning demand, a TDF generic still has a place in the current HIV regimen and may be aggressively embraced by insurers and other providers wanting to trim medication costs. And, ultimately, the more generic competitors there are in a market, the lower the prices will go.

That has certainly been the case with the generic version of Epzicom, a two-in-one option containing abacavir and lamivudine. With both drug components still recommended for first-line therapy, four manufacturers have jumped on the generic bandwagon and have managed to offer savings of up to 70 percent off that of the brand name version.

HIV Drug Manufacturers Shielded From Generic Price Pressures

U.S. HIV drug manufacturers are in the unique position of having little competitive pressure from generic companies that might otherwise be nipping at their heels.

Firstly, the consumer demand for one-pill options has made individual tablets far less attractive in anything but later-stage therapy. Not surprisingly, the patents for many of these combination tablets are nowhere near the end of their lifespan, with some like Truvada (TDF plus emtricitabine) only due to expire in 2021.

So even if individual drug components are available to generic manufacturers, the consumer will more often opt for the brand name combination tablet (unless, of course, an insurer forces them to do otherwise).

But, even beyond the issue of consumer demand, the competitive playing field in the U.S. has long been slanted in the direction of the non-generic HIV drug manufacturer. This is due in large part to the fact that the U.S. government is the single largest purchaser of antiretroviral drugs today.

Through the federally mandated AIDS Drug Assistance Program (ADAP), state governments are directed to buy HIV drugs directly from wholesalers. Prices are set through the Federal 340B Drug Pricing Program, which discounts the average wholesale price by anywhere from 60 to 70 percent. After factoring in rebates, the brand name drugs almost always end up being cheaper than their generic counterpart.

Another factor shielding pharmaceuticals is the way in which treatment is dispensed. Unlike private health insurance, ADAP treatment choice is directed solely by guidelines issued by the Department of Health and Human Services, which currently place all-in-one combination tablets—the very drugs protected by patents—as the preferred option in first-line therapy.

In the end, it is not “collusion” driving these directives. Studies have long shown that people on a one-pill therapy are more likely to remain adherent compared to those taking several pills. This, in turn, translates into higher rates of sustained viral suppression, meaning that the virus is unable to replicate and you are far less likely to develop drug resistance.

Fair or not, these policies can’t help but favor the non-generic manufacturer, making it far more difficult for generic companies to compete on anything but a tangential level.

To further protect their market position, almost all brand name manufacturers have agreed to offer financial support to those who cannot afford their drugs, either in the form of co-pay assistance or the subsidization of care for those who don’t qualify for insurance. It’s an offering generic manufacturers are hard-pressed to match.

But, as valuable as these incentives are, they still don’t address the generally high cost of HIV drugs when compared to the same medications available outside of the U.S.