The HIV medication tenofovir alafenamide fumarate (TAF), which is a new, safer version of Viread (tenofovir disoproxil fumarate, or TDF), offers premium benefits such that its average wholesale would be worth no more than an extra $1,000 per year, aidsmap reports. Researchers used a mathematical model to weigh the relative benefits of the two antiretrovirals and published their findings in Clinical Infectious Diseases.

The analysis assumed that all Americans taking TDF-containing regimens could switch immediately to comparable TAF-containing regimens. The researchers further assumed that 0.5 percent of those taking TDF would experience toxicities in their kidneys and have to stop taking the drug. One in four of those individuals would then need dialysis, which would cost $87,600 per year. Kidney disease and dialysis were both presumed to significantly impact quality of life.

The researchers also presumed that one in three people on TDF would experience bone loss at the hip, and 19 percent would do so at the vertebrae. An assumed 5 percent of those experiencing such bone loss would suffer a fracture in the current year, one that would significantly impact quality of life.

Given all these assumptions, the researchers calculated that TAF offered a maximum premium value of $1,000 per person per year over TDF.

To read the aidsmap article, click here.

To read the paper’s abstract, click here.