Spiro-Azetidine Oxindoles as Long-Acting Injectables for Pre-Exposure Prophylaxis against Respiratory Syncytial Virus...

Area of Science:

• Virology
• Immunology
• Medicinal Chemistry

Background:

• Respiratory syncytial virus (RSV) significantly impacts vulnerable populations, including infants, the elderly, and immunocompromised individuals, leading to substantial hospitalizations.
• Current preventive measures like monoclonal antibodies and vaccines primarily target infants and the elderly, leaving a critical gap for immunocompromised patients.
• There is an unmet need for effective strategies to prevent RSV disease in immunocompromised individuals.

Purpose of the Study:

• To develop novel small molecule inhibitors targeting RSV entry.
• To evaluate the potency and pharmacokinetic properties of spiro-azetidine oxindoles as potential RSV therapeutics.
• To assess the feasibility of long-acting formulations for sustained RSV protection in immunocompromised populations.

Main Methods:

• Synthesis and characterization of spiro-azetidine oxindoles.
• In vitro assessment of RSV entry inhibition.
• Evaluation of developability attributes and pharmacokinetic profiles.
• Formulation development for long-acting intramuscular (IM) or subcutaneous (SC) injections.

Main Results:

• Spiro-azetidine oxindoles demonstrated potent inhibition of RSV entry.
• These compounds exhibited favorable developability characteristics.
• Long-acting pharmacokinetic profiles were achieved with aqueous suspension formulations.
• Potential for 3- to 6-month protection with 1-2 IM or SC injections was suggested.

Conclusions:

• Spiro-azetidine oxindoles represent a promising class of small molecule RSV entry inhibitors.
• Long-acting formulations offer a potential strategy for sustained RSV prevention in immunocompromised patients.
• These findings may lead to new options for managing RSV complications in high-risk populations.