August 14, 2012
Generic-Based Regimen in U.S. Could Save Nearly $1 Billion in First Year of Use
by Tim Horn
Though it won’t be quite as convenient and could have a slight negative effect on HIV survival expectations, prescribing a generic equivalent to Atripla (efavirenz plus tenofovir and emtrictabine) could end up saving United States drug-coverage entities close to $1 billion in the first year alone. This is the conclusion of mathematical modeling conducted by Rochelle Walensky, MD, of Harvard Medical School and her colleagues, presented Friday, July 27, at the XIX International AIDS Conference (AIDS 2012) in Washington, DC.
"A switch from first-line branded to generic antiretrovirals will result in a lifetime average savings of $42,500 [per patient] and a modest survival loss of 0.37 quality-adjusted life years [roughly four months]," said Walensky, who noted that the estimates are based on very conservative modeling and may therefore downplay the actual cost savings and over-estimate the survival loss.
Walensky’s group used Atripla as an example for a variety of reasons. First, because it has long been a Department of Health and Human Services-preferred treatment regimen for people initiating therapy for the first time because of its strong long-term efficacy, overall safety profile and ease of use. Second, because a generic version of lamivudine—a nucleoside analog that works similarly to the emtricitabine in Atripla—is currently available and a generic equivalent of efavirenz is expected to be approved within the next year.
“We’re looking at the possibility of a potent, largely generic, first-line regimen in the U.S.,” Walensky explained. Generic efavirenz and lamivudine, she added, would be combined with Viread-brand tenofovir (Viread's patent does not expire until 2017).
Though Walensky and her colleagues note that the cost of the regimen will be less than Atripla—the average wholesale price (AWP) of which is currently $2,080 a month—some drawbacks are possible.
“Though still once-daily,” Walensky said, “a generic regimen will have an increased pill burden—three versus one pill—which may result in poorer adherence and virologic outcomes.” Additionally, replacement of emtricitabine with lamivudine may diminish the potency as a first line-regimen. It may also diminish the potency of second-line regimens, assuming that lamivudine, compared with emtricitabine, is more likely to lead to resistance mutations that can hinder the use of other nucleoside analogs.
Taking these variables into consideration, Walensky’s group performed some mathematical modeling that assumed the worst in terms of treatment adherence and regimen potency. The model compared outcomes for hypothetical patients starting therapy for the first time—averaging 43 years of age and a pre-treatment CD4 count of 317 cells—using Atripla or Viread plus generic efavirenz and lamivudine.
Worst-case scenario—assuming there really is a potency difference between Atripla and generic efavirenz and lamivudine plus Viread—78 percent of people living with HIV starting the generic regimen would have undetectable viral loads within 24 weeks (dubbed “early suppression” by the researchers) compared with 85 percent of those receiving Atripla. Long-term treatment failure, defined as those who achieved undetectable viral loads within 24 weeks but experienced a virologic rebound after six months of therapy, could potentially occur in 5.41 patients for every 100 patient-years of generic-equivalent treatment, compared with 2.5 per 100 patient-years of Atripla treatment.
Considering a 75 percent price reduction for the two generic drugs—an assumption based on price reductions seen when other drugs became available generically, notably Zocor-brand simvastatin for high cholesterol (66 percent), Methylin-brand methylphenidate for ADHD (72 percent) and Coumadin-brand warfarin for blood clots (85 percent)—Viread plus efavirenz and lamivudine would cost $9,200 a year ($766 a month).
This, Walensky said, would save the U.S. health care system $920 million in the first year alone.
If the price reduction for the two generics didn’t exceed 20 percent, the U.S. health care system would still save $200,000 in the first year. And if there was a 95 percent reduction in the price for the two generic drugs, the system would save approximately $1.1 billion in the first year.
Atripla’s annual price was calculated at $15,900, with the model including a 23 percent price reduction to entice U.S. health care systems to cover its cost.
Over the span of a lifetime, the total cost to the health care system for someone living with HIV not started on antiretroviral treatment would be $131,200. Among those who begin therapy with brand-name Atripla, the lifetime cost was calculated to be $342,800. For those who begin therapy with the generic-based regimen, the lifetime cost was calculated to be $300,300—a savings of approximately $42,500 per person.
Walensky’s team also calculated patients’ quality-adjusted life-years (QALYs), which take into account both the quantity and quality of life generated by a specific health care intervention. Without the use of any antiretrovirals, the hypothetical patients used in the model could expect a little more than four years of healthy living (4.05 QALY). With the generic regimen, the worst-case scenario QALY is bumped up to 12.05. With the use of Atripla, the calculated QALY is somewhat higher at 12.45—a 4.5-month survival advantage.
These findings, while economically encouraging, raised some important questions for Walensky and her colleagues. “Are we, as a society, ready to forgo small individual survival benefits for large national savings? Do we recognize that economic savings will vary among payers—for example state AIDS Drug Assistance Programs, state Medicaid programs and the U.S. Veterans Administration? Are we prepared for the fact there is no guarantee that money saved will be reinvested in HIV care?”
Such reinvestment, Walensky noted, is an important issue. She explained that President Obama’s 2012 National HIV/AIDS Strategy is explicitly financed, not by new funds, but by “repurposed” money. “If investment in the national HIV mission required ‘redirected’ financing, $1 billion saved from use of generic drugs might be an attractive source for this national reinvestment.”
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