715P Nivolumab in pretreated metastatic penile squamous cell carcinoma: Results of the penile cohort from the French AcSé prospective program

Abstract

Cisplatin-based chemotherapy has shown benefits in the first line setting in patients (pts) with advanced or metastatic penile squamous cell carcinoma (PSCC). However, there is no standard second line treatment. AcSé Nivolumab (N) is a French exploratory program assessing the value of anti-PD1 immunotherapy in pts with rare cancers (NCT03012581). AcSé N is a single arm basket phase II multicentric study aiming to investigate efficacy and safety of N monotherapy. Pts with relapsing/refractory PSCC were eligible after at least 1 line of chemotherapy in radical or palliative settings in a dedicated cohort. Primary endpoint was objective response rate (ORR) at 12 weeks according to RECIST v1.1. Pts received N 240mg IV q2w for a max of 2 years, until disease progression (PD) or intolerable toxicity. Secondary endpoints included progression free survival (PFS), overall survival (OS), best ORR, and safety. 43 PSCC pts were enrolled. Median age was 63, ECOG PS 0/1 in 24%/76% of pts. N was used in 2nd line (35% of pts), 3rd line (44%), and 4th line or beyond (19%). The median number of previous lines of chemotherapy was 2. Metastastic sites were lymph nodes (47%), lung (24%), liver (8%), and bone (6%). The median number of cycles was 5. With a median follow up of 7.9 months (mo), 40 pts (93%) had discontinued N. The 12-week ORR was 14% (4 partial response [PR]), 32% of pts had stable disease (SD), and 54% PD. In intention-to-treat population, the best ORR was 14% (2 CR + 4 PR) with SD in 16% of pts. At the time of analysis, 39 pts (90%) had PD, the 6-month PFS rate was 27.9% (95% CI [17.3; 45.1]), and median PFS 2.9 mo (95% CI [2.3; 5.3]). Moreover, 28 pts (65%) had died (all in PD), the 12-month OS rate was 34.5% (95% CI [22.1; 53.7]), and median OS 8.5 mo (95% CI [4.5; 18.4]). Overall, 3 pts (7%) had at least one grade ≥3 AE. We report the largest prospective study of anti-PD1 immunotherapy in advanced PSCC. Despite a low ORR of 14%, the median OS of 8.5 mo is higher than reported in most studies. These results are encouraging for pts without alternative validated treatments. The value of HPV status as predictive factor will be investigated.