Drug Resistant HIV May Be Overcome With Long-Acting ART

Results from a phase 3 study of the investigational antiretroviral ibalizumab for multi-drug resistant (MDR) HIV showed significant promise fighting the disease.

Findings showed that ibalizumab met its primary endpoint by significantly reducing the viral load in patients with MDR HIV-1. The results came from the 24-week, single-arm, phase 3 TMB-301 study of ibalizumab plus optimized background regimen in treatment-experienced patients infected with MDR HIV-1.

Researchers enrolled a total of 40 patients into the study. The primary objective of TMB-201 was to demonstrate the antiviral activity of ibalizumab 7 days after the first dose. During a 7-day control period, researchers monitored participants who were receiving their current failing antiretroviral therapy (ART) or no therapy.

Participants were then administered a loading dose of 2000-mg of ibalizumab intravenously, which was the only ART added to their regimen. The primary efficacy endpoint of the study is the proportion of patients who achieved a ≥ 0.5 log decrease in HIV-1 RNA 7 days after the start of treatment with ibalizumab and day 14 of the study.

Ibalizumab was continued at 800-mg IV doses every 2 weeks through 24 weeks. Upon completion of treatment, participants are offered participant in the expanded access TMB-311 study. Additional results from the trial showed that MDR HIV-1 patients experienced a significant decrease in viral load after receiving a loading dose of 2000-mg ibalizumab intravenously, in addition to failing ART therapies or no therapy.

The findings were statistically significant in demonstrating that 7 days after the loading dose, 83% of patients achieved a ≥ 0.5 log decrease from baseline compared with 3% during the 7-day control period. During this same period, 60% of participants achieved a decrease of ≥ 1.0 log (p<0.0001). For the total population, the average viral load decrease was 1.1 log (p<0.0001). Researchers reported no treatment-related adverse events and no discontinuations during the initial 7-day treatment period.

“These results are particularly exciting as ibalizumab, if approved by the FDA, would be the first long-acting biologic to show such efficacy in patients with highly resistant HIV-1,” said Jacob Lalezari, Medical Director, Quest Clinical Research. “The study suggests that when combined with other agents, ibalizumab could help these patients in dire need of new treatment options, and could change the way multi-drug resistant HIV is managed in the future.”

So far the FDA has granted ibalizumab Breakthrough Therapy designation and Orphan Drug designation. Now, with the completion of the study, Theratechnologies Inc plans to move forward with the filing of a Biologics License Application to the FDA.

“We understand the challenges faced by people living with HIV and are committed to improving their lives,” said Luc Tanguay, president and ceo of Theratechnologies. “We are excited about the potential benefits ibalizumab represents in the fight against HIV, and we will continue to work with our partner, TaiMed Biologics, towards the potential launch of ibalizumab in a timely manner.”