Intraperitoneal Alpha-Radioimmunotherapy of Advanced Ovarian Cancer in Nude Mice Using Different High Specific...

Area of Science:

• Oncology
• Radiotherapy
• Immunotherapy

Background:

• Advanced ovarian cancer remains a significant therapeutic challenge.
• Alpha-radioimmunotherapy (α-RIT) offers a targeted approach for cancer treatment.
• The monoclonal antibody (mAb) MX35 F(ab')2 labeled with 211At is a promising agent for α-RIT.

Purpose of the Study:

• To investigate the therapeutic efficacy of α-radioimmunotherapy with varying specific activities of 211At-MX35 F(ab')2 in a preclinical model of advanced ovarian cancer.
• To determine the impact of specific activity on the reduction of macroscopic ovarian tumors.

Main Methods:

• Ovarian cancer cell line NIH:OVCAR-3 was used to establish tumors in mice.
• Mice received intraperitoneal injections of 211At-MX35 F(ab')2 at different doses (25, 50, 400 kBq) and specific activities (1/80, 1/500, 1/1200).
• Tumor presence was assessed macroscopically, and statistical analysis (logistic regression) was performed to evaluate the effect of specific activity.

Main Results:

• A significant trend was observed where higher specific activity correlated with a lower probability of macroscopic tumors (P = 0.02).
• Across different activity levels, increasing specific activity led to a reduction in the number of animals with macroscopic tumors.
• The study demonstrated a dose-dependent relationship between specific activity and therapeutic effectiveness.

Conclusions:

• Increasing the specific activity of 211At-MX35 F(ab')2 is a viable strategy to improve therapeutic outcomes in advanced ovarian cancer, specifically in reducing macroscopic tumor burden.
• Further research into the role of specific activity in α-RIT is warranted to optimize treatment protocols.
• This preclinical study supports the potential of tailored α-RIT for ovarian cancer management.