Fc Multisite Conjugation and Prolonged Delivery of the Folate-Targeted Drug Conjugate EC140

Area of Science:

• Biotechnology
• Drug Delivery Systems
• Oncology

Background:

• Small molecule-drug conjugates (SMDCs) offer targeted drug delivery but face pharmacokinetic challenges, including short in vivo half-lives.
• Limited circulation time restricts SMDC exposure to tumor tissues, reducing therapeutic effectiveness.

Purpose of the Study:

• To engineer a novel SMDC with an extended half-life and improved anti-tumor efficacy.
• To chemically conjugate the folate-targeted SMDC EC140 to a long-circulating Fc protein.

Main Methods:

• Developed a high-drug-antibody ratio (DAR) Fc-SMDC conjugate (Fc-EC140) by chemically linking EC140 to an Fc protein.
• Assessed Fc-EC140's potency in folate receptor (FR)-positive tumor cells and its pharmacokinetics, including FcRn-mediated recycling and half-life in mice.
• Evaluated in vivo anti-tumor efficacy of Fc-EC140 in KB tumor models.

Main Results:

• Fc-EC140 demonstrated enhanced potency in FR-positive tumor cells compared to EC140 alone.
• The conjugate exhibited an extended half-life of 28 hours in mice, attributed to FcRn-mediated recycling.
• Intravenous administration of Fc-EC140 resulted in near-complete tumor eradication in KB xenografts, significantly outperforming the EC140 comparator.

Conclusions:

• The developed Fc-SMDC conjugate (Fc-EC140) represents a promising strategy for overcoming the pharmacokinetic limitations of SMDCs.
• This approach enhances targeted drug delivery and significantly improves anti-tumor efficacy in vivo.
• Fc-EC140 offers a potential advancement in cancer therapy through improved SMDC design.