First-in-India Experience with 90Y-BhabhaSphere: An Indigenous 90Y-TheraSphere Biosimilar for Transarterial radioembolization of Hepatic Malignancies.

Objective: Primary and secondary hepatic malignancies are a significant cause of cancer-related mortality worldwide. Radioembolization with yttrium-90 (90Y) microspheres has emerged as a promising treatment option for unresectable hepatic tumors. However, the high cost of commercially available Y-90 microspheres, such as 90Y-TheraSphere or 90Y-SirSphere, limits their accessibility in developing countries. We present the first Indian clinical experience of indigenously developed [90Y] Yttria Alumino Silicate glass microspheres, known as "90Y-BhabhaSphere," for radioembolization of hepatic malignancies.

Methods: "90Y-BhabhaSphere" formulation developed at XXXXXX XXXXXX XXXXXXXX XXXXXX (XXXX), XXXXX, was used to treat a small cohort of five patients with unresectable hepatic malignancies. The 90Y-BhabhaSphere delivery system was developed through a rigorous process and in vitro tested using a microcatheter connection to simulate the TARE procedure. Feasibility, safety, delivery efficiency and preliminary efficacy of treatment using 90Y-BhabhaSphere were assessed.

Results: Our initial clinical experience with 90Y-BhabhaSphere demonstrates its safety and feasibility in treating hepatic malignancies. 90Y-BhabhaSphere demonstrated excellent delivery efficiency, reaching 99% in vitro (dummy run) and 97% in vivo (clinical delivery) 90Y-BhabhaSphere was successfully administered to four patients, whereas in one patient the delivery had to be terminated due to a leakage in the delivery system. The treatment was well-tolerated, with minimal adverse effects. Preliminary efficacy analysis shows promising results, with a significant reduction in tumor size and improvement in liver function.

Conclusion: 90Y-BhabhaSphere offers a cost-effective alternative to commercially available 90Y-microspheres. Our initial clinical experience demonstrates its safety, feasibility, and preliminary efficacy in treating hepatic malignancies. Large clinical trials need to be conducted to establish the long-term efficacy and safety of 90Y-BhabhaSphere.

Advances in knowledge: This study highlights a key advantage of 90Y-BhabhaSphere: its significantly higher specific activity (approximately 6000 Bq/sphere) compared to commercially available 90Y-TheraSphere (2700 Bq/sphere). This suggests a potential for delivering higher tumor doses whileminimizing radiation exposure to healthy liver tissue, thereby reducing the risk of radiation-induced liver damage.