Tibotec Pharmaceuticals announced results from two pivotal phase-3, double-blind, randomized clinical trials comparing the efficacy, safety and tolerability of its investigational non-nucleoside reverse transcriptase inhibitor (NNRTI) TMC278 (rilpivirine) versus efavirenz (EFV), each administered once daily with a nucleoside/nucleotide background regimen in treatment-naive, HIV-1-infected adults.

These global trials, known as ECHO and THRIVE, reached their primary objective, which was to demonstrate non-inferiority of TMC278 vs. EFV in the proportion of patients achieving an undetectable viral load (less than 50 copies/mL) at week 48 (with a maximum allowable difference of 12 per cent). A pooled analysis of ECHO and THRIVE was presented at the XVIII International AIDS Conference in Vienna, Austria.

ECHO and THRIVE pooled results showed that 84.3 per cent of patients (n=686) in the TMC278 group reached an undetectable viral load, compared with 82.3 per cent of patients (n=682) in the EFV group. The difference between the treatment groups was not significant. Patients received TMC278 (25 mg) or EFV (600 mg), each administered once daily in combination with a nucleoside/nucleotide background regimen. The virologic failure rate was 9 percent in the TMC278 group and 4.8 percent in the EFV group.

TMC278 is an investigational product, and the safety and efficacy has not yet been established. Tibotec plans to submit these results to the US Food and Drug Administration (FDA) to support approval of TMC278 for use in treatment-naive adult patients.

"I'm very excited by the findings of these phase-3 results for TMC278," said Calvin J Cohen, lead clinical investigator and Research Director at Community Research Initiative of New England and Harvard Vanguard Medical Associates. "These studies provide valuable information on the safety and tolerability of TMC278 and, specifically, its metabolic and CNS side effect profiles."

Adverse events (AEs) leading to discontinuation in the TMC278 group were 3.4 per cent compared to 7.6 per cent in the EFV group, and Grade 2-4 AEs at least possibly related to treatment were 15.9 per cent in the TMC278 group versus 31.1 per cent in the EFV group. Grade 2-4 AEs of interest by organ class reported among patients in the TMC278 group versus the EFV group were psychiatric (14.9 percent vs. 22.7 per cent), neurological (17.1 per cent vs. 37.8 per cent) and rash-all types (3.1 per cent vs. 13.6 per cent). Grade 3/4 lipid abnormalities were also reported among patients in the TMC278 group versus the EFV group for increases in total cholesterol (0.1 per cent vs. 2.5 per cent), LDL-cholesterol (0.7 per cent vs. 4.1 per cent) and triglycerides (0.3 per cent vs. 2.2 per cent).

Tibotec Pharma is a pharmaceutical research and development company. The company's main research and development facilities are in Beerse, Belgium, with offices in Titusville, New Jersey, USA.