Pembrolizumab combined with cisplatin or carboplatin and etoposide in treatment naïve advanced Merkel cell carcinoma (MCC): The phase II PANDORA Trial

#4601

Introduction: MCC is a rare and aggressive skin neuroendocrine tumour with high metastatic potential and mortality. Therapeutic options in metastatic/unresectable MCC are based on immunotherapy or platinum-based chemotherapy. However, a subgroup of patients (pts) has primary immunoresistance disease, so it would be important discover active upfront combinations. PANDORA trial [NCT 06086288] is an open-label, multicentre, single-arm phase II trial evaluating the activity and safety of pembrolizumab (PEM) combined with platinum-based chemotherapy as 1st line treatment in pts with metastatic, unresectable or recurrence MCC. Supported in part by a research grant from Investigator-Initiated Studies Program of MSD.

Aim(s): Primary endpoint is objective response rate. Secondary objectives are overall survival, progression-free survival and duration of response.

Materials and methods: Study design includes an induction phase with 4 cycles of PEM 200mg plus carbo/cisplatin and etoposide every 3 weeks, following by maintenance therapy with PEM 400mg every 6 weeks (for a maximum of 24 months). A minimax Simon two-stage design will be applied. We planned to enrol 35 pts: 24 in 1st stage and 11 in 2nd one. If complete (CR) or partial response (PR) is assessed in at least 15 pts in the 1st stage, the 2nd stage will be performed, otherwise the study will be closed. If CR o PR is assessed in at least 23 pts, this combination will be considered worthy of further investigation.

Conference:

Presenting Author: Oldani S

Authors: Oldani S, Morano F, Cingarlini S, Di Giacomo A, Borghesani M,

Keywords: Pembrolizumab, clinical trial, Merkel cell carcinoma, chemio-immunotherapy,