First Experiences with ¹⁷⁷Lu-PSMA Therapy in Combination with Pembrolizumab or After Pretreatment with Olaparib in Single Patients.

Abstract

Synergistic effects of immunotherapy with pembrolizumab or drugs targeting DNA damage, such as olaparib, might be used to overcome the limitations of radioligand therapy (RLT) with ¹⁷⁷Lu-prostate-specific membrane antigen (PSMA) in metastasized castration-resistant prostate cancer. Here, we present 2 patients receiving such combination or sequential therapies. <b>Methods:</b> RLT was performed at 6- to 8-wk intervals after the patients either exhausted or were considered unfit for all approved conventional treatments. Patient 1 was on pembrolizumab for his squamous cell carcinoma of the skin, whereas patient 2 received RLT sequentially 4 wk after 3 mo of monotherapy with olaparib. <b>Results:</b> Both patients tolerated RLT without any significant hematotoxicity. Patient 2 showed a radiologic and biochemical response, whereas patient 1 achieved prostate-specific antigen stabilization after 3 therapy cycles. <b>Conclusion:</b> These cases indicate that RLT in combination with pembrolizumab or sequentially after olaparib might be well tolerated in single patients.