This study aimed to estimate the rate of generic users among HIV-infected patients treated by antiretroviral (ARV) drugs potentially substitutable and to determine factors associated with switch from brand to generic ARV in real-life settings in a French region.

Cohort of HIV-infected patients aged of ≥18 years, exposed to at least one of the generic of lamivudine (3TC-150mg/300mg), zidovudine/lamivudine (AZT-200mg/3TC-150mg), nevirapine (NVP-200mg), efavirenz (EFV-600mg) and those exposed to brand 3TC, AZT/3TC, NVP, EFV, the fixed-dose combination abacavir/lamivudine (ABC/3TC) or the single-tablet regimen efavirenz/emtricitabine/tenofovir (EFV/FTC/TDF) as recorded in the French health insurance database between January 2012 and May 2015 were included. Factors associated with switch (for each generic versus its brand drug; and for situation requiring breaking the combination) were investigated through a logistic regression.

Among the 1539 patients likely to switch from brand ARV drugs, only 165 (11%) were exposed to generics. For EFV users, switch from brand to generic was associated with age (aOR=1.04 [CI: 1.00–1.08]). For ABC/3TC users, switch was significantly more frequent in patients receiving a monthly average of more than two non-ARV drugs (3.08 [1.42–6.68]) and whose regimen contained a non-nucleoside reverse transcriptase inhibitor (NNRTI) as index medication (3rd agent) (5.68 [2.68–11.39]). By contrast, switch was less frequent in AZT/3TC users exposed to drugs used in digestive disorders (0.39 [0.18–0.88]) or analgesics (0.42 [0.20–0.90]).

Treatment-experienced HIV patients whose disease has been stabilized (less comorbidities) are more likely to switch to generic antiretroviral drugs.