TY - JOUR T1 - <strong>Re-challenge [<sup>177</sup>Lu]Lu-PSMA-617 in patients with advanced prostate cancer: outcome and safety</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 526 LP - 526 VL - 59 IS - supplement 1 AU - Anna Yordanova AU - Markus Essler AU - Stefan Hauser AU - Georg Feldmann AU - Hojjat Ahmadzadehfar Y1 - 2018/05/01 UR - http://jnm.snmjournals.org/content/59/supplement_1/526.abstract N2 - 526Objectives: There is a sparse data regarding the feasibility of radioligand therapy (RLT) with [177Lu]Lu-PSMA-617 as a retreatment. We aimed to assess the outcome and safety of re-challenge RLT in patients with progressive prostatic cancer who previously benefited from the therapy. Materials and methods: Assessed were patients who received re-challenge therapy at our department from January 2015 to December 2017. Nonhematological and hematological adverse events were evaluated from laboratory data and clinical reports and were graded according to the Common Terminology Criteria for Adverse Events (CTCAE v. 4.02). Time to prostate-specific-antigen (PSA) progression and overall survival of the study patients were calculated from the date of the first re-challenge cycle. The response data was determined using [68Ga]Ga-PSMA-PET/CT and measurements of the tumor marker PSA. Results: Included in this retrospective study were 30 patients, who were initially treated with a median of 3 cycles (range 1-5) RLT and were eventually retreated after a median of 6 months (range 2 - 26). Each patient received a median of 2 (range 1-6) re-challenge cycles. None of the patients experienced a disabling or life-threatening adverse event (CTC-4). Grade 3 toxicity occurred in 7 patients (23%). Serious adverse events included leucopenia (n=2), anemia (n=3), thrombopenia (n=3) and elevated renal parameters (n=1). According to PSA-measurements at least 4 weeks after the RLT-application between re-challenge-cycle 1 to 5 at least 75% of patients showed a response (PSA-decrease &gt;= 25%) or stable PSA-levels (change &lt; 25%). Sixteen patients (53%) are alive; the median overall survival is still not reached. Conclusion: Re-challenge PSMA therapy is with an acceptable safety profile. The majority of the re-treated patients showed a benefit. ER -