First experiences with Lu-177 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 e.g. olaparib could be used to overcome the limitations of radioligand therapy (RLT) with Lu-177 prostate specific membrane antigen (PSMA) in metastasized castrate resistant prostate cancer (mCRPC) patients. Here, we present two patients receiving such combination / sequential therapies. Methods: RLT was performed at 6-8 week intervals after they either exhausted or were considered unfit for all approved conventional treatment. Patient 1 was on pembrolizumab for his squamous cell carcinoma of the skin whereas patient 2 received RLT sequentially 4 weeks after a 3 months monotherapy with olaparib. Results: Both patients tolerated RLT without any significant hematotoxicity. Patient 2 showed radiological and biochemical response whereas patient 1 achieved PSA stabilization after 3 therapy cycles. Conclusion: These cases indicate that RLT in combination with pembrolizumab or sequentially after olaparib might be well tolerated in single patients.