HIV Viral Suppression Accelerated with Monoclonal Antibody

Theratechnologies Inc. recently presented data from a study in which the use of Trogarzo® (ibalizumab), a monoclonal antibody antiretroviral therapy (ART), was associated with favorable virologic outcomes compared to non-ibalizumab regimens used in routine care in heavily treatment-experienced people with HIV.

In the new study, using ibalizumab resulted in a statistically significant doubling of the likelihood of viral undetectability and a much longer duration of undetectability and viral suppression compared to a real-world, non-ibalizumab control group from the Observational Pharmaco-Epidemiology Research & Analysis (OPERA®) database.

The ibalizumab study is thought to be the first matching-adjusted indirect treatment comparison study in HIV, an approach designed to facilitate a closely matched comparison from a synthesized, real-world population when randomization to a control arm would be impractical or unethical.

Christian Marsolais, Ph.D., Senior Vice President and Chief Medical Officer of Theratechnologies, stated in a press release on May 4, 2023, “This is the largest dataset and longest follow-up for Trogarzo® since our Phase 3 study, and reinforces its importance in a patient population that historically has had limited novel treatment options.”

The study evaluated data from 76 participants in two clinical trials (Phase 2b and Phase 3) who received 800 mg of ibalizumab every two weeks (treatment arm) and compared those data to outcomes from 65 individuals treated with non-ibalizumab-containing regimens as routine care in the OPERA® cohort (control arm).

Standardized mortality rate weighting ensured a balance between the treatment and control groups regarding baseline age, CD4 cell count, viral load, and susceptibility to specific ART agents.

At 24 weeks, investigators observed a statistically significant doubling of the likelihood of viral undetectability (defined as VL <50 c/mL) in the treatment arm versus the control arm (SMR-weighted hazard ratio [HR]: 1.98; 95% confidence interval [CI]: 1.02, 3.69).

Achievement of viral suppression (defined as VL <200 c/mL) was also more likely with ibalizumab, though this finding did not reach statistical significance (SMR-weighted HR: 1.28; 95% CI: 0.82, 2.06).

Among those who achieved undetectability on ibalizumab, 95% maintained undetectability through the end of follow-up.

Additionally, the exact significance emerged for maintaining viral suppression, which was 18 times lower for real-world non-ibalizumab regimens.

For both durability analyses, confidence intervals were wide but statistically significant (SMR-weighted HR: 18.36; 95% CI: 2.48, 135.68).

Note: Monoclonal antibody antiretroviral therapy is not an HIV vaccine candidate.