A new non-nucleoside reverse transcriptase inhibitor, rilpivirine, has been approved for first-line antiretroviral treatment by the United States Food and Drug Administration.
Rilpvirine (brand name Edurant) is licensed for use in combination with other antiretroviral drugs, and manufacturer Johnson & Johnson/Tibotec is partnering with Gilead to develop a three-drug combination pill that will allow rilpivirine to be taken in one tablet with tenofovir and FTC.
Rilpivirine, previously known as TMC-278, was licensed on the basis of clinical trials that compared the drug with efavirenz, the most commonly prescribed first-line NNRTI. In one study the drugs were tested in combination with tenofovir and FTC; in the other, the drugs were tested in combination with one of three nucleoside analogue combinations (tenofovir/FTC, AZT/3TC or abacavir/3TC).
In a press release announcing the approval of rilpivirine, the US Food and Drug Administration noted that the clinical trials that led to the licensing of rilpivirine had demonstrated a similar rate of viral load suppression after 48 weeks of treatment.
However, patients with viral load above 100,000 copies/ml at the beginning of treatment were less likely to achieve undetectable viral load than those with lower viral load when treated with rilpivirine. As a consequence a higher rate of viral failure was observed in patients who received rilpivirine (13% vs 9%).
Patients who experienced viral failure were also much more likely to develop drug resistance, both to NNRTIs and to 3TC or FTC.
In patients receiving efavirenz there was no difference in viral load response according to the level of viral load at the beginning of treatment.
These studies also showed that patients taking rilpivirine were less likely to stop treatment due to central nervous system side-effects such as insomnia, depression, dizziness, or due to rash, when compared to patients taking efavirenz.
Rilpivirine is taken once daily with food.
European marketing authorisation is likely to be granted in the second half of 2011.