Abstract CT167: Neoadjuvant ipilimumab/nivolumab in locally advanced or oligometastatic melanoma: An open label, single arm, multi-institutional clinical study with molecular and immunological biomarker’s analysis

Abstract

Abstract Efficacy, safety, together with molecular and immunological biomarkers were studied in a sequential clinical trial of neoadjuvant immunotherapy, surgery and adjuvant immunotherapy in locally advanced or oligometastatic melanoma patients (pts), within an open label, single arm and two sites study. Treatment schedule consisted in four primary cycles of inverted dose ipilimumab 1 mg/kg and nivolumab 3 mg/kg every 3 weeks, followed by radical surgery and adjuvant nivolumab 480 mg every 4 weeks for 6 cycles. Primary objective was pathological complete remission (pCR) rate, according to International Neoadjuvant Melanoma Consortium (INMC) criteria, while secondary objectives were: safety, feasibility and efficacy; QoL; identification of biomarkers of response and resistance; degree of immune activation; longitudinal evaluation of the gut microbiome. From March 2019 to April 2021, 43 pts were enrolled in the trial and, with an intent to treat of 35 pts, 34 completed the primary phase, 31 received surgery and 28 completed the adjuvant phase. Four pts were withdrawn during primary phase for progression (2), toxicity (1) and consent withdrawal (1). Study primary endpoint has been met since 20/31 pts undergoing surgery reached a pCR/near pCR (65%), 4/31 (13%) a pathological partial remission (pPR) and 7/31 (22%) pts a pathological no response. With a median follow-up of 17 months, 33/35 pts are alive. Treatment failure occurred in 9 pts: 2 pts progressed during primary phase and did not undergo surgery; 7 pts progressed during adjuvant (3 pts) or follow-up phase (4 pts). Six out of these 7 pts were classified as pNR at surgery, while the other, classified as pCR, did not receive adjuvant therapy. Both pts in stage IV relapsed. Unfortunately, one pt died for ischemic stroke after 5 months from adjuvant therapy while on CR. Treatment related toxicities were mainly G1-2 and only 6 pts (17%) developed G3-4 adverse events (AE): 3 transaminitis, 1 pneumonitis, 1 myocarditis, 1 CPK increase and 1 dermatomyositis. Translational studies on samples collected before, during therapy and at progression have been performed: whole exome sequencing and gut microbiota dynamics on longitudinal samples showed some relationships with responses and developing resistances. These data, never presented elsewhere previously, are in part new and in part confirmatory of immunological or molecular signatures described by other groups. In conclusion, primary immunotherapy with Ipilimumab/Nivolumab in pts affected by locally advanced/oligometastatic melanoma is able to achieve an elevated pCR/near pCR rate which appears to be predictive of long term relapse free survival. Translational data analyzed longitudinally on each patient can allow for a better selection of pts, giving new insight on the mechanisms of melanoma progression and resistance. Citation Format: Pier Francesco Ferrucci, Bruno Achutti Duso, Luigi Nezi, Luca Mazzarella, Fiorenza Lotti, Sara Gandini, Gianmarco Orsolini, Elisabetta Pennacchioli, Patrizia Gnagnarella, Teresa Manzo, Simone Ribero, Maria Teresa Fierro, Rebecca Senetta, Concetta Riviello, Virginia Caliendo, Pietro Quaglino, Massino Barberis, Giuseppina Bonizzi, Emilia Cocorocchio. Neoadjuvant ipilimumab/nivolumab in locally advanced or oligometastatic melanoma: An open label, single arm, multi-institutional clinical study with molecular and immunological biomarker’s analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT167.