Weight Gain After Switch from Efavirenz-Based to Integrase Inhibitor-Based Regimens

BACKGROUND: Integrase strand transfer inhibitor (INSTI)-based antiretroviral therapy (ART) offers persons living with HIV a potent new treatment option. Recently, local HIV clinicians noted weight gain in patients who switched from daily, fixed-dose efavirenz/tenofovir disoproxil fumarate/emtricitabine (EFV/TDF/FTC) to fixed-dose dolutegravir/abacavir/lamivudine (DTG/ABC/3TC). To assess whether regimen switch was significantly associated with weight gain, we evaluated body weight over time among patients with sustained virologic suppression who switched from EFV/TDF/FTC to an INSTI-containing regimen, including DTG/ABC/3TC. METHODS: We analyzed data from adult patients on EFV/TDF/FTC for >=2 years with consistent plasma HIV-1 RNA <1000 copies/mL prior to date of switch (or date of sham switch for those who remained on EFV/TDF/FTC). All maintained HIV-1 RNA <1000 copies/mL for >=18 months post-switch. We assessed weight change over 18 months in patients switched to an INSTI-containing regimen or a protease inhibitor (PI)-containing regimen vs. those remaining on EFV/TDF/FTC over the same period. In a sub-group analysis, we compared patients switched to DTG/ABC/3TC vs. raltegravir- or elvitegravir-containing regimens. Linear mixed effects models assessed mean differences in weight over time, adjusting for baseline age, sex, race, CD4+ count and weight. RESULTS: Among 495 patients, 136 switched to an INSTI-containing regimen, 34 switched to a PI-containing regimen, and 325 remained on EFV/TDF/FTC. Patients switched to an INSTI-containing regimen gained an average of 2.9 kilograms (kg) at 18 months compared with 0.9 kg among those continued on EFV/TDF/FTC (P = 0.003, Figure a), while those switched to a PI regimen gained 0.7 kg (P = 0.81, Figure b). Among INSTI regimens, those switched to DTG/ABC/3TC gained 5.3 kg at 18 months, which was more than raltegravir or elvitegravir regimens (P = 0.19, Figure c) and significantly more than those continued on EFV/TDF/FTC (P = 0.001, Figure d). CONCLUSION: Switching from daily, fixed-dose EFV/TDF/FTC to an INSTI-containing regimen among patients with virologic control was associated with weight gain at 18 months. This weight gain was particularly profound among those switching to DTG/ABC/3TC. DISCLOSURES: All authors: No reported disclosures.