1076 - Early Results from a Randomized Phase II Trial Testing Apalutamide and Stereotactic Body Radiation Therapy for Low-Burden Mhspc (NCT05717660)
Presenter(s)
G. Francolini1, M. Loi1, V. Di Cataldo1, P. Garlatti1, S. Caini2, A. Bruni3, N. Simoni4, M. Augugliaro5, L. Tagliaferri6, G. Ingrosso7, G. Vullo8, G. C. Iorio9, A. Reali10, A. Guarneri11, M. F. Osti12, A. Di Grazia13, M. Aquilano14, G. Simontacchi1, D. Greto1, and L. Livi1; 1Radiation Oncology Unit, Azienda Ospedaliero Universitaria Careggi, University of Florence, Florence, Italy, 2Cancer Risk Factors and Lifestyle Epidemiology Unit, Institute for Cancer Research, Prevention and Clinical Network (ISPRO), Florence, Italy, 3Radiation Oncology Unit, Department of Oncology and Hematology, University Hospital of Modena, Modena, Italy, 4Radiotherapy Unit, Azienda Ospedaliera Universitaria, Parma, Parma, Italy, 5Unit of Radiotherapy, Azienda USL-IRCCS di Reggio Emilia, Reggio emilia, Italy, 6Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy, 7Hospital S.Maria della Misericordia, Perugia, Perugia, Italy, 8Department of Radiation Oncology, University General Hospital, Udine, Udine, Italy, 9Department of Oncology, Radiation Oncology, University of Turin, turin, Italy, 10Radiation Oncology Department, Michele e Pietro Ferrero Hospital, Verduno, Italy, 11Radiation Oncology, Candiolo Cancer Institute, FPO-IRCCS, turin, Italy, 12Radiotherapy Department, St. Andrea Hospital, Sapienza University of Rome, Rome, Italy, 13Radioterapia Humanitas, Istituto Clinico Catanese, Catania, Italy, 14Cyberknife Unit, Istituto Fiorentino di Cura ed Assistenza, IFCA, Florence, Italy
Purpose/Objective(s):
Overall survival of metastatic hormone sensitive prostate cancer (mHSPC) patients was significantly improved by the addition of Apalutamide to standard androgen deprivation therapy (ADT) alone. Moreover, concomitant use of Stereotactic body radiotherapy (SBRT) and Androgen Receptor Pathway inhibitors (ARPIs) showed to improve clinical outcomes of oligometastatic castrate resistant prostate cancer in a randomized phase II trial (ARTO, NCT03449719). Nonetheless, concomitant use of SBRT and ARPIs in oligometastatic HSPC currently relies on sparse literature evidences. PERSIAN (NCT 05717660) is a trial aiming to test the hypothesis that SBRT will improve outcomes in oligometastatic HSPC undergoing Apalutamide+ADT.Materials/Methods:
PERSIAN is a phase II randomized trial including oligometastatic HSPC (< 5 distant metastases) affected by metachronous disease. Patients with de novo metastatic disease or visceral metastases are excluded from the trial. Patients are randomized to Apalutamide+ADT alone (ARM A: Control) or Apalutamide+ADT+SBRT on all sites of metastatic disease evidenced on conventional imaging (ARM B: Treatment). Here is presented an early analysis focusing on complete biochemical response (defined as PSA<0.2 ng/ml) after 3 months from systemic treatment start.Results:
Overall, 180 patients have been enrolled within the trial, of whom 87 reached a minimum follow up of 3 months. Of these, complete biochemical response was detected in 91.1 vs 92.9% cases in the control vs treatment arm, respectively (OR 1.27, 95% CI 0.27-6.03, p=0.765). No association between response and site of metastases (nodal only vs bone) was detected (OR 1.39, 95%CI 0.29-6.67, p-value 0.678). Presence of a consistent number of lesions on PSMA and conventional imaging was not associated with response (OR 0.74, 95%CI 0.08-6.94, p=0.791). When adjusted for number of lesions, a significant benefit in favour of experimental arm was detected for patients with <3 metastatic sites (OR 5.88, 95%CI 1.13-33.3, p=0.03).Conclusion:
Despite the early phase of the trial, a non significant trend in favour of SBRT addition was found, with a 21% odds increase in the overall sample. Patients with lower burden of disease (< 3 distant metastases) may gain significant advantage from concomitant treatment. PERSIAN trial completed the accrual in November 2024, early results about complete biochemical response at 6 months in the complete cohort will be available in the second half of 2025.