NEW YORK (Reuters Health) – More than one in 10 patients taking a generic medicine for HIV preexposure prophylaxis (PrEP) switched to an equally effective but more expensive version, often without a documented clinical reason, a study from Boston has found.
When taken as prescribed, antiretroviral PrEP is 99% effective in preventing HIV infection. It is available in two forms: co-formulated tenofovir disoproxil fumarate and emtricitabine (TDF/FTC, or Truvada, generic) and the newer tenofovir alafenamide with emtricitabine (TAF/FTC, or Descovy).
Both medications are equally safe and effective. The older version has been associated with small decreases in renal function and bone-mineral density, while the newer one has been associated with minor weight gain and lipid changes, but these small differences have not translated to differences in adverse clinical events.
Cost is the big difference. Generic TDF/FTC costs as little as $30 per month, compared with about $1,800 per month for TAF/FTC.
“We wanted to understand how often PrEP users were switching from the old PrEP medication, TDF/FTC or Truvada, to the much more expensive new one, TAF/FTC or Descovy, and how often there were documented clinical reasons to make that switch,” Dr. Julia Marcus of Harvard Medical School and Harvard Pilgrim Health Care Institute, in Boston, told Reuters Health by email.
Using electronic health record data, the study team evaluated 2,892 men (mean age, 38 years) who were prescribed TDF/FTC for PrEP in the year before U.S. approval of TAF/FTC, and had at least one PrEP prescription in the following year.
All of the men were seen at Fenway Health, a Boston community health center that specializes in care for sexual and gender minorities.
According to the Open Forum Infectious Diseases report, 343 men (12%) switched to the newer TAF/FTC in the first year it was available.
Based on documented renal, bone, and cardiovascular risk factors, only 24 (7%) of those who switched to TAF/FTC had clinical indications to do so; 271 (79%) cases involved “potentially unnecessary switching” and 48 (14%) involved “potentially harmful switching.”
When indications for switching also included hypertension, diabetes and creatine clearance 60 to 70 mL/min, which are risk factors for developing renal dysfunction, 27% of switching was clinically indicated, the team reports.
“Given its robust evidence base and cost-effectiveness, some community advocates and health professionals have recommended that TDF/FTC remain first-line for PrEP. But as a result of intensive marketing, clinicians or PrEP users may favor switching to Descovy even when TDF/FTC would be just as safe and effective,” Dr. Marcus told Reuters Health.
“Even when we defined clinical indications generously, we still found that only a minority had a documented clinical reason to switch to Descovy. Some PrEP users may prefer Descovy because of its smaller pill size, but others may be making the switch because of a perception that Descovy is a superior medication,” she noted.
“Our findings suggest that the marketing of Descovy has been successful, driving pharmaceutical profits rather than broader or more equitable access to PrEP,” Dr. Marcus added. “Given the two medications that have comparable safety and effectiveness, it makes good sense to prioritize the much cheaper one for most patients.”
The study was supported in part by the National Institute of Allergy and Infectious Diseases. Dr. Marcus has previously consulted for Kaiser Permanente Northern California on a research grant from Gilead Sciences unrelated to the submitted work. Gilead Sciences makes Descovy.
SOURCE: https://bit.ly/3jkA7cY Open Forum Infectious Diseases, online August 5, 2021.
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