Table 2.
Changes from initial regimens to new regimens that are considered switchesa
| Regimen classification | Switch from (PI + ≥ 2 NRTI)? | Switch from (bPI + ≥ 2 NRTI)? | Switch from (NNRTI + ≥ 2 NRTI)? | Switch from (< 6 drugs including FI/INSTI + (entry inhibitors))? |
|---|---|---|---|---|
| PI + ≥ 2 NRTI | Nob | No | Yes | Yes |
| bPI + ≥ 2 NRTI | Yes | Yes if PI changesb | Yes | Yes |
| NNRTI + ≥ 2 NRTI | Yes | Yes | Yes if NNRTI to etravirine (ETV)b | Yes |
| bPI + PI/NNRTI (+ other) | Yes | Yes | Yes if NNRTI to etravirine (ETV)b | Yes |
| < 6 drugs including FI/INSTI (+ entry inhibitors) | Yes | Yes | Yes | Yes if FI/II/entry inhibitor changes or addition of a FI/II/entry inhibitorb |
If the cell reads ‘no’, this type of change is never considered a switch. Changes to regimen classifications other than those in the table are never switches. If the cell reads ‘yes’, this type of change is always considered a switch. If the cell reads ‘yes if …’, the condition(s) listed must be met for the change to be considered a switch. Other aspects of the regimen may also change or stay the same.
Individuals must change to regimens that do not include any of the following drugs: zalcitabine (DDC), alovudine (ALO), capravirine (CPV), DPC 083 (DPC083), delavirdine (DLV), emivirine (EMV), lodenosine (DDA or LDN), loviride (LOV), mozenavir (MOZ), vicriviroc (VIC) or any unspecified drugs (ART, PI, NNRTI, NRTI).
PI, protease inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; bPI, boosted protease inhibitor; NNRTI, nonnucleoside reverse transcriptase inhibitor; FI, fusion inhibitor; INSTI, integrase strand transfer inhibitor.
aEligible regimens were determined by a panel of clinicians on the basis of treatment guidelines.
bOur primary definition of switching above does not include NRTI-only changes. An alternative definition includes some NRTI-only changes (i.e. any NRTI to tenofovir (TNV) and tenofovir (TNV) to zidovudine (AZT)). According to this alternative definition, a change where the regimen classification does not change is considered a switch if any part of the regimen changes (according to the conditions above).