Efficacy and Safety of 177Lu-DOTA-IBA in Tumor Bone Metastasis Treatment: A Prospective Clinical Trial.

Purpose: The aim of this study was to evaluate the efficacy and safety of 177Lu-DOTA-IBA for pain palliation in participants with bone metastases and confirm its potential for treating bone metastasis.

Patients and methods: Overall, 69 participants with bone metastases were included. 68Ga-DOTA-IBA PET/CT was performed within 1 week before treatment. Vital signs, blood markers, electrocardiogram, Karnofsky Performance Status (KPS), and pain scores were evaluated within 7 days before treatment. Postadministration of 177Lu-DOTA-IBA, participants' vital signs and general conditions were monitored. Follow-up evaluations of KPS, pain scores, and blood biomarkers were performed within 8 weeks. 68Ga-DOTA-IBA PET/CT was repeated to evaluate imaging responses at 8 weeks. Imaging responses were defined as complete response, partial response, stable disease, and disease progression. Subsequent treatments were administered based on participants' agreement and clinical conditions.

Results: Sixty-nine participants received at least 1 dose of 177Lu-DOTA-IBA treatment; 22 received 38 reinjected doses, totaling 107 treatments. The median injection dose of 177Lu-DOTA-IBA was 1110 MBq. The pain remission rates after first treatment, retreatment, and total treatment were 82.5%, 72.4%, and 79.3%, respectively. The improvement rates in KPS for first treatment, retreatment, and total treatment were 81.3%, 60.6%, and 74.2%, respectively. The total incidence of the pain flare reaction (temporary aggravation of pain intensity after treatment) was 16.8%. Comparative analysis of 68Ga-DOTA-IBA PET/CT showed a 27.1% rate of partial response imaging response. The total incidence of adverse hematological events was 15%.

Conclusions: 177Lu-DOTA-IBA is a promising bone-seeking radiopharmaceutical with a considerable pain relief rate and safety. It also can benefit some participants with bone metastases in imaging response.