Capsid-Targeting Biologic Achieves Broad HIV-1 Neutralization with a High Barrier to Resistance

Area of Science:

• Virology
• Drug Discovery
• Immunology

Background:

• Antiretroviral therapy (ART) effectively suppresses HIV-1, but drug resistance and viral adaptation necessitate new treatments.
• The HIV-1 capsid is a conserved and critical viral target for novel inhibitors.
• A novel capsid-targeting biologic has been developed for efficient degradation of newly synthesized capsid, inhibiting HIV-1 replication.

Purpose of the Study:

• To investigate the sensitivity to viral escape and the breadth of a novel capsid-targeting biologic against HIV-1 subtypes.
• To evaluate the resistance profile and neutralization potential of anti-capsid biologics.

Main Methods:

• Testing the biologic's efficacy against various primary HIV-1 isolates.
• Assessing viral breakthrough and characterizing resistance mutations upon continuous exposure.
• Evaluating the biologic's activity against diverse HIV-1 subtypes (A, B, C, D, CRF01_AE, CRF02_AG).

Main Results:

• The capsid-targeting biologic efficiently blocked replication of multiple primary HIV-1 isolates.
• Viral breakthrough occurred in two of ten isolates, with resistance mutations primarily in the matrix region, not the nanobody epitope.
• Breakthrough variants showed reduced sensitivity but remained susceptible, and demonstrated increased replication kinetics in the absence of the biologic.
• The biologic demonstrated broad specificity, blocking infection across various global HIV-1 subtypes.

Conclusions:

• Capsid-targeting biologics exhibit broad neutralization potential with a high barrier to resistance.
• These findings support the development of capsid-targeting inhibitors as crucial components of novel antiretroviral drug strategies.
• The conserved nature of the capsid target limits viral escape, underscoring the therapeutic promise of these agents.